Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 01/09/07

...STRONG OFFSHORE WINDS AND VERY DRY WEATHER WILL START THE WEEK...

...INSIDE SLIDER FOR LATE WEEK...WITH POSSIBLE RETURN TO STRONG OFFSHORE WINDS FOR NEXT WEEKEND...

.SHORT TERM... STRONG HIGH PRESSURE SYSTEM OVER THE GREAT BASIN WILL LINGER THROUGH MONDAY. THIS WILL KEEP A TIGHT OFFSHORE PRESSURE GRADIENT PATTERN OVER THE REGION TODAY AND MONDAY. CURRENT LAX GRADIENTS ARE 8.7 MB OFFSHORE TO DAGGETT...8.8 MB OFFSHORE TO BAKERSFIELD AND 12.7 MB AND INCREASING TO TONOPAH. THIS IS PRODUCING WIDESPREAD OFFSHORE WINDS OVER MUCH OF THE REGION...WITH THE STRONGEST WINDS OCCURRING OVER PORTIONS OF LA AND VENTURA COUNTIES. STRONGEST WINDS AT THIS TIME WERE NORTHEAST 53 GUSTING TO 85 AT CHILAO. HOWEVER...THE GRADIENT TREND IS ONSHORE AT LAX-BFL...HOLDING LAX-DAG...AND INCREASING LAX-TPH. THIS IS EXPECTED AS THE FOCUS OF THE STRONGEST WINDS SHIFTS FROM NORTHERLY TO MORE NORTHEASTERLY.

THE COMBINATION OF DRY AIR...LOTS OF SUNSHINE...AND COMPRESSIONAL WARMING OF THE NORTHEAST WINDS WILL GIVE US A NICE WARM DAY TODAY. TEMPERATURES ALMOST EVERYWHERE ARE UP 5 TO 10 DEGREES THIS MORNING COMPARED TO YESTERDAY...WITH SOME AREAS UP 10 TO 20 DEGREES INCLUDING REDONDO...UCLA...PORTIONS OF MALIBU AND EVEN AVALON. THESE WARM TEMPERATURES ARE EXPECTED TO CONTINUE THROUGH MONDAY.

THE GREAT BASIN HIGH SHIFTS TO COLORADO LATE TUESDAY AS GRADIENTS BEGIN TRENDING ONSHORE OVER THE REGION. TUESDAY WILL STILL BE WARM...BUT A FEW DEGREES COOLER THAN MONDAY. GRADIENTS BECOME ONSHORE ON WEDNESDAY EVERYWHERE AND TEMPERATURES ARE EXPECTED TO DROP 5 TO 12 DEGREES FROM TUESDAYS HIGHS JUST ABOUT EVERYWHERE.

REGARDLESS....THE PATTERN REMAINS DRY THROUGH THE SHORT TERM.

.LONG TERM... MEDIUM RANGE MODEL AGREEMENT LOOKS GOOD RIGHT THROUGH THE WEEK... BEFORE SOLUTIONS BEGIN TO DIVERGE NEXT WEEKEND. THIS SHOULD GIVE GOOD CONFIDENCE IN THE FORECAST FOR THE WEEK. BOTH THE ECMWF AND THE GFS HAVE A DOMINANT UPPER RIDGE OVER THE EASTERN PACIFIC TODAY. THIS HIGH SHIFTS ONSHORE AND FLATTENS TUESDAY WITH THE UPPER LEVEL FLOW BECOMING MORE ZONAL. ON WEDNESDAY...BOTH MODELS SHOW A TROUGH DEVELOPING OVER MUCH OF THE WEST...AS AN INSIDE SLIDER DEVELOPS OVER THE PACNW. THIS INSIDE SLIDER MOVES SOUTHWARD TOWARDS THE REGION ON THURSDAY AND PASSES OVER LAS VEGAS BY LATE FRIDAY. THE UPPER LOW THEN SHIFTS TO OUR EAST AND SETS UP STRONG UPPER LEVEL SUPPORT FOR A POTENTIALLY VERY WINDY NEXT WEEKEND...AGAIN.

OVERALL...THE PATTERN LOOKS MAINLY DRY FOR THE WEEK...EXCEPT FOR THURSDAY AND FRIDAY WHEN THERE IS A CHANCE FOR SOME SHOWERS. AT THIS TIME...THIS ONLY LOOKS LIKE A SLIGHT CHANCE AT THAT.

&&

.AVIATION...STRONG OFFSHORE FLOW WILL CONTINUE ACROSS THE SOUTHLAND S OF POINT CONCEPTION...AS WELL AS N OF POINT CONCEPTION BUT MUCH WEAKER TO THE NORTH. S OF POINT CONCEPTION...EXPECT STG UDDF AND LLWS ACROSS MANY AIR FIELDS THROUGH MONDAY AFTERNOON...ESPECIALLY KBUR AND KVNY. SOME SPEED SHEAR COULD AFFECT SOME AIRCRAFT NEAR LAX...BUT THE FOCUS SHOULD REMAIN OVER THE MOUNTAINS AND VALLEYS WITH THE GREATEST UDDF AND LLWS.

KLAX WILL EXPERIENCE NORTHEAST WINDS BETWEEN 6 TO 12 KT AT THE SURFACE. SOME SOME SPEED SHEAR COULD AFFECT AIRCRAFT BELOW 10K FT.

&&

.LOX WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING (SEE LAXNPWLOX). RED FLAG WARNING (SEE LAXRFWLOX). WIND ADVISORY (SEE LAXNPWLOX). GALE WARNING (SEE LAXCWFLOX). SMALL CRAFT ADVISORY (SEE LAXCWFLOX). MARINE WEATHER STATEMENT (SEE LAXMWSLOX).

&&

$$

PUBLIC...DANIELSON AVIATION...KAPLAN

.SYNOPSIS...HIGH PRESSURE OVER THE INTERIOR AND STRONG UPPER LEVEL FLOW WILL CAUSE LOCAL STRONG GUSTY OFFSHORE WINDS...MAINLY THROUGH AND BELOW MOUNTAIN CANYONS AND PASSES THROUGH MONDAY. OTHERWISE...FAIR WITH WARMER DAYS...ESPECIALLY WEST OF THE MOUNTAINS. LOW PRESSURE WILL BRING MUCH COOLER WEATHER WITH A CHANCE OF SHOWERS TOWARD THE END OF THE WEEK.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES...

.SHORT TERM (TODAY-TUESDAY)...CLEAR SKIES EARLY THIS MORNING EXCEPT FOR A FEW HIGH CLOUDS. EARLY MORNING ACARS SOUNDINGS INDICATED WEAK NE WINDS IN THE LOW LEVELS WITH MODERATELY STRONG NLY WINDS ALOFT. OFFSHORE GRADIENTS WITH ABOUT -10 MB SAN-TPH.

THERE WILL CONTINUE TO BE ENOUGH UPPER LEVEL...THERMAL AND GRADIENT SUPPORT FOR LOCAL STRONG OFFSHORE WINDS AT TIMES INTO MON. THE WINDS WILL BE STRONGEST IN THE MORNINGS THROUGH AND BELOW MOUNTAIN CANYONS AND PASSES. WIND WARNINGS IN EFFECT FOR THE MOUNTAINS AND INLAND EMPIRE WITH WIND ADVISORIES FOR THE ORANGE COUNTY COASTAL AREAS AND SAN DIEGO INLAND VALLEYS INTO MON. THE DRY OFFSHORE FLOW WILL MAINTAIN A HIGH FIRE WEATHER THREAT AND A RED FLAG WARNING REMAINS IN EFFECT FOR THE MOUNTAINS AND INLAND VALLEYS THROUGH MON AFTERNOON. RIDGING ALOFT WILL BRING INCREASING HEIGHTS INTO MON FOR WARMING IN ALL AREAS. MORE WARMING W OF THE MOUNTAINS DUE TO THE OFFSHORE FLOW WITH SOME MAX TEMPS IN THE 80S LIKELY BY MON. A LITTLE COOLER IN MOST AREAS TUE AS THE HIGH ALOFT AND OFFSHORE FLOW WEAKEN. MOSTLY CLEAR SKIES EXCEPT FOR HIGH CLOUDS AT TIMES.

.LONG RANGE (WEDNESDAY-SATURDAY)...A COLD UPPER TROUGH OF LOW PRESSURE WILL DIG S OVER THE SW WED THROUGH FRI. MOISTURE IS LIMITED WITH THIS SYSTEM BUT THERE COULD BE ENOUGH COLD AIR ALOFT AND OVER WATER TRAJECTORY FOR A CHANCE OF A FEW LIGHT SHOWERS THU THROUGH SAT. MUCH COLDER DURING THE END OF THE WEEK. GUSTY OFFSHORE WINDS SHOULD DEVELOP AS THE TROUGH SHIFTS E NEXT WEEKEND.

&&

.AVIATION... CLEAR SKIES AND VFR CONDITIONS WITH UNRESTRICTED VISIBILITIES WILL PREVAIL UNDER CONTINUED OFFSHORE FLOW TODAY...EXCEPT LOCALLY IN AREAS OF BLOWING DUST. NE WINDS 10 TO 15 KT THROUGH 7K FT EARLY THIS MORNING...WILL GRADUALLY INCREASE TO NEAR 30 KT BY THIS EVENING. STRONGER GRADIENT FLOW WILL FUNNEL THROUGH MOUNTAIN PASSES AND CANYONS LATER THIS MORNING...CREATING LOCALLY STRONGER AND GUSTY WINDS IN EXCESS OF 40 KT...WITH ASSOCIATED AREAS OF TURBULENCE...LOW LEVEL WIND SHEAR...AND STRONG UP AND DOWN DRAFTS. ALSO MOUNTAIN WAVE AND ROTOR ACTIVITY COULD OCCUR ON THE COASTAL SIDE OF MOUNTAIN RANGES AS THE WINDS INCREASE.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...

HIGH WIND WARNING UNTIL 2 PM MONDAY FOR THE MOUNTAINS AND INLAND EMPIRE. SEE LAXNPWSGX.

WIND ADVISORY UNTIL 2 PM MONDAY FOR ORANGE COUNTY COASTAL AREAS AND SAN DIEGO COUNTY VALLEYS. SEE LAXNPWSGX.

RED FLAG WARNING FOR THE MOUNTAINS AND INLAND VALLEYS THROUGH MONDAY AFTERNOON. SEE LAXRFWSGX.

$$

PUBLIC...DVA AVIATION...JAD

.SHORT TERM...

SOUTHERN STREAM SHORT WAVE QUICKLY LIFTING NORTHEAST THIS AFTERNOON ACROSS THE OH VALLEY. WATER VAPOR SHOWS DRYING MOVING INTO SOUTHWEST FORECAST AREA ALREADY. THIS IS MUCH FASTER THAN 12Z MODEL DEPICTION. RADAR ALSO CONFIRMS THIS WITH BACK EDGE OF RAIN INTO CENTRAL INDIANA. NORTHERN STREAM SHORT WAVE APPROACHING FOR THIS EVENING. REGIONAL RADAR MOSAIC SHOWS SOME LIGHT PCPN DEVELOPING AHEAD OF THIS FEATURE ALONG LEADING EDGE OF SURFACE COLD FRONT. MODELS LOOK LIKE THEY HAVE FAILED TO CAPTURE DRY SLOT BETWEEN THESE TWO SYSTEMS. FEEL MOISTURE MAY BE OVERDONE SLIGHTLY. HOWEVER...NAM-WRF DOES BRING A 150KT 300MB JET MAX INTO THE OH VALLEY THIS EVENING WITH OUR EASTERN AREA IN FAVORABLE LEFT FRONT QUAD. CROSS SECTIONS FROM NAM-WRF ALSO SHOW A FAVORABLE NEGATIVE POTENTIAL VORTICITY AREA OVER TOP OF FRONTOGENETICAL FORCING AND DENDRITIC GROWTH AREA. 850-925MB LAYER FAVORABLE FOR SNOW BUT BOUNDARY LAYER BORDERLINE. MODELS HAVE BEEN TOO WARM TODAY WITH THIS NEAR SURFACE LAYER AND ALL SNOW REPORTED THIS AFTERNOON ACROSS FAR NORTH. WITH 1000-850MB THICKNESS VALUES NEAR 1300M FEEL MIX OF SNOW AND RAIN WILL CONTINUE FAR NORTH INTO THIS EVENING. REST OF AREA SHOULD SEE MAINLY RAIN EARLY THIS EVENING BUT QUICK TRANSITION TO SNOW AS NORTHERN WAVE MOVES IN. FAR NORTHEAST HAS BEST CHANCE FOR ACCUMULATION WITH ONE TO MAYBE TWO INCHES POSSIBLE. REST OF AREA SHOULD SEE A QUICK SHOT WITH LIGHT ACCUMS OF A DUSTING TO LOCALLY AN INCH. DRIER AND COLDER AIR TO MOVE IN BEHIND SURFACE FRONT OVERNIGHT. TEMPS IN WEST TO DROP WITH PARTIAL CLEARING POSSIBLE LATE. HAVE CUT MOS WEST BUT STAYED CLOSE IN THE EAST. MAV MOS LOOKS TOO WARM MONDAY GIVEN COLD AIR ADVECTION AND INCREASING CLOUDS IN THE AFTERNOON AHEAD OF NEXT CLIPPER. CONTINUED WITH COLDER MAX TEMPS. COULD ALSO BE SOME LIGHT LAKE EFFECT SNOW SHOWERS OR FLURRIES BUT LOW LEVEL MOISTURE IS MEAGER AND FLOW QUICKLY BACKING. STAYED WITH LOW CHANCE POPS.

&&

.LONG TERM... MONDAY NIGHT THROUGH SUNDAY...CONCERNS/CHALLENGES ARE MAINLY AT THE BEGINNING AND END OF THIS PERIOD. A CLIPPER TYPE OF SYSTEM WILL DESCEND INTO THE MIDWEST MONDAY NIGHT. HAVE USED NGM/NAMWRF/GFS BLEND AND GONE WITH LIKELY SNOW CHANCES EVERYWHERE WITH AROUND AN INCH OF SNOW AS THE SYSTEM MOVES ACROSS THE FORECAST AREA. 850 MB TEMPS COLDER THAN -5C AND 1000/850 THICKNESSES BELOW 1300 METERS INDICATE ALL SNOW. LEFT SOME LINGERING LAKE EFFECT SNOW SHOWERS IN TUESDAY WITH DELTA T VALUES RISING TO NEAR 17. TEMPERATURES SHOULD RECOVER TO MUCH ABOVE NORMAL THURSDAY AND FRIDAY AS A DEEP TROF DIGS OVER THE WEST CONUS WITH AN AMPLIFYING RIDGE DOWNSTREAM OVER THE EAST CONUS. THE EVENTUAL EJECTION OF THIS UPPER LEVEL SYSTEM AND THE AMOUNT OF COLD AIR IN THE LOWER LEVELS WILL BE THE KEY TO TIMING...AMOUNTS AND TYPE OF PRECIPITATION FRIDAY THROUGH SUNDAY. THE GFS HAD BEEN ADVERTISING THIS SYSTEM TAKING ON A NEGATIVE TILT WITH LARGE AMOUNTS OF RAIN ESPECIALLY SOUTH OF THE FORECAST AREA. LATER RUNS ABANDONED THIS SOLUTION...ONLY TO RETURN AGAIN WITH LATER RUNS. FOR THIS PACKAGE...HAVE GONE WITH A CHANCE FOR RAIN FRIDAY...AND A MIX OF RAIN AND SNOW POSSIBLE FRIDAY NIGHT THROUGH SUNDAY. FREEZING RAIN IS ALSO POSSIBLE IF ENOUGH SHALLOW COLD IS ABLE TO SPREAD OVER THE AREA...BUT IT IS JUST TOO EARLY TO TRY TO PIN DOWN A LOCATION. IF THIS SYSTEM TAKES ON MORE OF A NEGATIVE TILT...EXPECT HEAVY PRECIPITATION WILL BE POSSIBLE.

&&

.AVIATION... AN UPPER LEVEL SYSTEM WILL RACE ACROSS THE REGION THIS AFTERNOON AND EARLY TONIGHT. ACARS SOUNDINGS INDICATED LOW LEVELS VERY CLOSE TO SUPPORTING A MIX OF RAIN AND SNOW...SO HAVE STARTED PCPN WITH A MIX AT SBN. NOTICED ASW WITH LIGHT SNOW...BUT A CALL TO WARSAW INDICATED JUST RAIN. OTHERWISE...AN UPPER LEVEL TROF WILL IMMEDIATELY FOLLOW THE FIRST SYSTEM TONIGHT WITH WINDS BECOMING WEST. ANY SNOW OR MIX SHOULD END OVERNIGHT WITH CONDITIONS IMPROVING SOME.

&&

.IWX WATCHES/WARNINGS/ADVISORIES... IN...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR INZ005. MI...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR MIZ078-MIZ079. OH...NONE. LM...SMALL CRAFT ADVISORY TONIGHT THROUGH MONDAY AFTERNOON. &&

$$

SHORT TERM...LASHLEY AVIATION...LASHLEY/SKIPPER LONG TERM...SKIPPER

.AVIATION... AN UPPER LEVEL SYSTEM WILL RACE ACROSS THE REGION THIS AFTERNOON AND EARLY TONIGHT. ACARS SOUNDINGS INDICATED LOW LEVELS VERY CLOSE TO SUPPORTING A MIX OF RAIN AND SNOW...SO HAVE STARTED PCPN WITH A MIX AT SBN. NOTICED ASW WITH LIGHT SNOW...BUT A CALL TO WARSAW INDICATED JUST RAIN. OTHERWISE...AN UPPER LEVEL TROF WILL IMMEDIATELY FOLLOW THE FIRST SYSTEM TONIGHT WITH WINDS BECOMING WEST. ANY SNOW OR MIX SHOULD END OVERNIGHT WITH CONDITIONS IMPROVING SOME.

&&

.PREV DISCUSSION...

UPDATE... AREAS OF FOG HAVE FORMED QUICKLY THIS MORNING MAINLY ALONG AND NORTH OF U. S. 30. SOME VSBYS ACROSS THE REGION HAVE BEEN REPORTED AS LOW AS A QUARTER OF A MILE. HAVE SENT AN UPDATE TO THE ZONES/GRIDS TO REFLECT THIS CHANGE. WILL ALSO ISSUE A NOWCAST...HIGHLIGHTING THE POTENTIAL FOR SOME OF THE FOG TO FREEZE ON SURFACES...RESULTING IN BLACK ICE.

SHORT TERM... TODAY AND TONIGHT.

THE SHORT TERM FCST WILL BE COMPLEX OVER THE NEXT 24 HOURS. 00Z NAM-WRF AND 00Z GFS ARE FAIRLY SIMILAR IN THEIR SYNOPTIC SOLUTIONS. THUS...A BLEND OF THE TWO MODELS WILL BE USED.

WATER VAPOR IMAGERY THIS MORNING DEPICTED A S/WV TROF ACRS THE WRN HIGH PLAINS. THIS S/WV IS FCST TO MOVE EAST OVER THE NEXT 24 HOURS...WITH THE TROF AXIS PASSING ACRS THE WRN GREAT LAKES REGION BETWEEN 06Z AND 12Z MONDAY MORNING. THIS SYSTEM WILL INTERACT WITH A PLUME OF SUBTROPICAL MOISTURE WHICH WAS RAPIDLY MOVING NE INTO THE MID MS AND LOWER OHIO RIVER VLYS. THIS SUBTROPICAL MOISTURE WAS AHEAD OF ANOTHER S/WV LOCATED OVER THE SRN PLAINS/NRN TEXAS. THIS S/WV WILL BECOME ABSORBED INTO THE MAIN AFOREMENTIONED S/WV. AS THIS HAPPENS...AN AREA OF SFC LOW PRESSURE WILL MOVE RAPIDLY NE OUT OF THE LOWER MS RIVER VLY INTO ERN OHIO BY 06Z MONDAY. WAA/ISENTROPIC LIFT IN ASSOCIATION WITH THIS LOW WILL CAUSE SHOWERS TO DEVELOP THIS AFTN ACRS THE SE CWFA. THEN...AS THE MAIN S/WV APPROACHES THIS EVENING...DYNAMICAL LIFT FROM THE S/WV...COMBINED WITH 850 MB TO 700 MB FRONTOGENETICAL FORCING ON THE BACK SIDE OF THE SFC LOW...WILL OCCUR...WHICH WILL RESULT IN A FAIRLY SUBSTANTIAL AREA OF RAIN/SHOWERS. THE HIGHEST LOW LVL THETA E AIR IS EXPECTED TO REMAIN TO THE SE OF THE FCST AREA. THUS...RAINFALL AMOUNTS TODAY INTO TONIGHT WILL RANGE FROM 0.15 TO 0.30 INCHES...WHICH IS GOOD CONSIDERING THE AMOUNT OF RIVER FLOODING THAT IS ONGOING. EVEN THOUGH IT APPEARS AT THIS POINT THAT A BASIN AVERAGE OF A QUARTER INCH WILL NOT BE ENOUGH TO PUSH THE SAINT JOSEPH RIVER ABOVE ITS FLOOD STAGE BY MONDAY AFTERNOON...IT WOULD BE PRUDENT TO KEEP CURRENT FLOOD WATCH GOING JUST TO MAKE SURE SUBSEQUENT MODEL RUNS DO NOT INDICATE HEAVIER RAINFALL. THE UPR TROF AXIS WILL BE ACCOMPANIED BY A COLD FRONT AS IT CROSSES THE FCST AREA BETWEEN 06Z AND 12Z. COLDER AIR WILL FILTER INTO THE REGION QUICKLY BEHIND FRONTAL PASSAGE...WHICH WILL CHANGE PCPN TO SNOW SHOWERS. SNOW ACCUMULATIONS ARE EXPECTED TO BE LESS THAN AN INCH BY MONDAY MORNING. WINDS WILL INCREASE LATE TONIGHT AS THE SFC PRESSURE GRADIENT TIGHTENS. HIGHS TODAY WILL RANGE FROM THE LOWER TO MID 40S. LOWS TONIGHT WILL FALL INTO THE UPPER 20S TO THE LOWER 30S.

LONG TERM... MONDAY THROUGH SATURDAY

MUCH COOLER AND MORE SEASONABLE AIR ON THE WAY FOR A FEW DAYS AT THE START OF THE LONG TERM BEFORE ANOTHER WARMUP FOR THE SECOND HALF OF THE WEEK...THEN POTENTIAL FOR A MORE LASTING PATTERN CHANGE TO COLDER MORE WINTRY WEATHER STARTING NEXT WEEKEND. PRIMARY FOCUS FOR THE LONG TERM REVOLVES AROUND SNOW POTENTIAL WITH A CLIPPER MON NGT THEN LAKE EFFECT POTENTIAL BEHIND IT TUE AND TUE NGT.

WATER VAPOR IMAGERY EARLY THIS MORNING SHOWS MAIN PLAYER IN THE FORM OF A WELL DEFINED SHORTWAVE MAKING LANDFALL ALONG THE BRITISH COLUMBIA COAST. BOTH NAM/GFS APPEAR TO HAVE A DECENT HANDLE ON INITIALIZATION OF THIS FEATURE IN H5 HEIGHT FIELDS...AND HAVE BEEN QUITE CONSISTENT THE PAST FEW RUNS ON TRACK/AMPLITUDE. GFS CONTINUES TO BE A LITTLE STRONGER WITH THIS WAVE...AND PREFER THIS STRONGER SPECTRAL MODEL SOLUTION OVER THE NAM GIVEN SATELLITE PRESENTATION OF THIS WAVE THE PAST FEW DAYS. AS THE POTENT SHORTWAVE APPROACHES SHOULD SEE A BRIEF SURGE OF LOW/MID LEVEL WAA/ISENTROPIC UPGLIDE. A SIMPLE GARCIA METHOD WOULD SUGGEST POTENTIAL FOR AN INCH OR SO OF ACCUM GIVEN FAST MOVEMENT AND LIMITED MOISTURE. CROSS SECTIONAL ANALYSIS SHOWING RATHER WELL DEFINED...ALBEIT WEAK FRONTAL CIRCULATION WITH WEAK FRONTOGENESIS AND THE UPWARD BRANCH OF THE AGEOSTROPHIC VERTICAL CIRCULATION PROGGED TO PASS OVER MOST OF THE CWA. ALSO SOME INDICATION OF WEAK BANDING POTENTIAL WITH A SMALL AREA OF NEGATIVE SATURATED EPV ATOP FRONTOGENESIS REGION. BEST EARLY ESTIMATE IS A GENERAL INCH OR SO ACCUM...WITH LOCAL AMOUNTS OF UP TO 2 INCHES ACROSS THE SOUTHERN HALF OF THE CWA...BUT PLACEMENT AND AMOUNTS STILL SOMEWHAT UNCERTAIN AT THIS TIME FRAME.

ATTENTION THEN SHIFTS FROM THE SYNOPTIC SCALE TO THE MESOSCALE. ANOTHER CAA SURGE BEHIND CLIPPER...THIS TIME ON MORE FAVORABLE NW FLOW DEVELOPS BY TUE AM. FLOW APPEARS WELL ALIGNED...AND INSTABILITY QUITE FAVORABLE WITH A MODERATE COLLIER INDEX. MAIN CONCERN AGAIN IS SYNOPTIC SCALE MOISTURE. NAM IS QUITE DRY IN THE LOW LEVELS WHILE THE GFS SHOWS SOMEWHAT BETTER LOW LEVEL MOISTURE. GIVEN UNCERTAINTY OF QUALITY OF MOISTURE...WILL KEEP POPS IN CHANCE CATEGORY FOR AREAS FAVORED IN NW FLOW FOR TUE INTO TUE NGT.

HIGH PRESSURE BUILDS ACROSS THE TENNESSEE VALLEY ON WED WITH LOW LEVEL WAA AND BACKING FLOW SHUTTING OFF ANY LAKE EFFECT. WILL SEE A RETURN TO ABOVE NORMAL TEMPS FOR SEVERAL DAYS THE SECOND HALF OF THE WEEK WITH A FEW NEEDED DRY DAYS. AS THIS IS OCCURRING...MAJOR TROUGH RELOADS ACROSS THE WESTERN CONUS AS TRUE ARCTIC AIR PLUNGES INITIALLY INTO THE WEST...AND THEN BLEEDS SLOWLY EAST AND SOUTHEAST BY NEXT WEEKEND. STRONG BAROCLINIC ZONE FORECAST TO SET UP FROM THE SW CONUS INTO THE OHIO VALLEY OR GREAT LAKES BY FRI AND CONTINUE THROUGH AT LEAST THE WEEKEND. THIS WILL LIKELY SET THE STAGE FOR ANOTHER MAJOR QPF EVENT IN THIS REGION. INITIAL SURGE OF WAA SHOULD KEEP TEMPS WARM ENOUGH FOR ALL LIQUID THU NGT INTO FRI. AFTER THAT...STILL MUCH UNCERTAINTY AS TO PLACEMENT OF BAROCLINIC BOUNDARY AND ABILITY OF LOW LEVEL ARCTIC AIR TO PENETRATE INTO THE CWA. MODELS ARE NOTORIOUSLY BAD FOR HANDLING ARCTIC AIRMASSES SUCH AS THIS. WILL KEEP GENERIC RA/SN MENTION FOR NOW GIVEN UNCERTAINTY IN PTYPE AS TEMPS COOL CLOSER TO THE FREEZING MARK.

&&

.IWX WATCHES/WARNINGS/ADVISORIES... IN...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR INZ005.

MI...FLOOD WATCH THROUGH MONDAY AFTERNOON FOR MIZ078-MIZ079.

OH...NONE. LM...NONE. &&

$$

SHORT TERM...LASHLEY/HICKMAN UPDATE...HICKMAN/LASHLEY AVIATION...SKIPPER/LASHLEY LONG TERM...HITCHCOCK/SKIPPER

.MORNING UPDATE...

DOING A QUICK UPDATE TO INSERT ISLD THUNDER INTO SRN KY AS CURRENT DATA INDICATES SOME EMBEDDED THUNDER NEAR THE KY/TN BORDER. NONE OF THE MODELS PICKED UP ON THIS ELEVATED INSTABILITY...THOUGH SDF ACARS SOUNDING INDICATED A WEAKLY UNSTABLE LAYER FROM 800-600MB. ALSO ADJUSTED THE BWG TAF TO INCLUDE HEAVY RAIN/VICINITY THUNDER AND LOWER VIS FROM 1445-1600 UTC.

ADJUSTED DEWPOINTS/TEMPS/WINDS TO REFLECT CURRENT CONDITIONS. ALSO BUMPED UP POPS TO CATEGORICAL SOONER.

ZFP/HWO UPDATE OUT VERY SHORTLY.

AL

&&

.LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. &&

$$

.SYNOPSIS... 20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED AN UPPER LEVEL TROUGH EXTENDING FROM THE UPPER MISSISSIPPI VALLEY INTO THE CENTRAL PLAINS...SITUATED BETWEEN RIDGES OVER THE EAST PACIFIC AND EASTERN U.S.. WITHIN THE TROUGH...SHRTWVS TO NOTE WERE OVER SE MINNESOTA AND ALONG THE MINNESOTA/DAKOTAS BORDER. DPVA AHEAD OF BOTH OF THESE SHRTWVS...COMBINED WITH PLENTY OF MOISTURE SEEN ON THE 12Z INL SOUNDING AND A 17Z TAMDAR SOUNDING FROM BRAINERD...HAS HELPED SUPPORT AN AREA OF LIGHT SNOW ACROSS MUCH OF DULUTHS FORECAST AREA. SOME OF THIS LIGHT SNOW HAS ALREADY SPREAD INTO THE WESTERN U.P. PER LOWER VISIBILITIES SEEN AT IWD AND CMX. DRIER AIR TO THE EAST AS SEEN ON THE 16Z SAWYER TAMDAR SOUNDING...COMBINED WITH SUNSHINE FILTERED THROUGH HIGH CLOUDS AND BREEZY SOUTHERLY WINDS HAVE ALLOWED TEMPERATURES TO CLIMB INTO THE UPPER 30S...WITH EVEN A FEW LOW 40S READINGS IN DOWNSLOPE AREAS. LOOKING AHEAD INTO THE FORECAST...IT WILL LIKELY BE A WHILE BEFORE WE SEE THESE READINGS AGAIN. AT THE SURFACE....1000MB LOW PRESSURE WAS SITUATED NEAR PICKLE LAKE WITH A COLD FRONT EXTENDING SOUTHWARD TO NEAR DUBUQUE. 850MB TEMPS FALL NEARLY 5C BEHIND THIS FRONT...FROM THE PRESENT -4C READINGS TO AROUND -9C AS SEEN ON THE BRAINERD SOUNDING. TO THE WEST OF THIS COOLER AIR...A HIGH PRESSURE RIDGE WITH PLENTY OF DRY AIR (NOTED BY THE LACK OF CLOUD COVER AND PRECIPITABLE WATER OF 0.19 INCHES ON THE 12Z BIS SOUNDING) WAS LOCATED OVER THE PLAINS. FARTHER TO THE WEST...A SHRTWV CAN BE SEEN DROPPING THROUGH ALBERTA...WITH AN ASSOCIATED 995MB LOW PRESSURE SITUATED OVER WEST CENTRAL ALBERTA.

&&

.SHORT TERM (TONIGHT AND MONDAY)...

UPPER LEVEL TROUGH OVER MINNESOTA WILL CROSS MOST OF UPPER MICHIGAN TONIGHT...ALONG WITH THE TWO SHRTWVS. DPVA AHEAD OF THESE SHRTWVS...COMBINED WITH ADVECTION OF MOISTURE FROM NORTHERN MINNESOTA SHOULD ALLOW FOR A TRANSLATION EASTWARD OF THE SNOW OVER DULUTHS AREA ACROSS THE CWA. THE 12Z GFS...WHICH HAS HAD AN EXCELLENT HANDLE ON THE SNOW SO FAR ALSO PRESENTS THIS IDEA...AND THEREFORE HAVE FOLLOWED MOST OF IT FOR THE FORECAST. THEREFORE... HAVE INCREASED POPS TO LIKELY AS THE SYNOPTIC SNOWFALL MOVES ACROSS. IT SHOULD BE NOTED THAT THE GFS SHOWS AN INCREASE OF 700MB OMEGA OVER THE CENTRAL U.P. AT 00Z THIS EVENING...WHICH RESULTS IN THE MODEL PRODUCING AROUND A TENTH OF AN INCH OF QPF. BECAUSE OF THIS...HAVE TRENDED QPF AMOUNTS UPWARDS...BUT DID NOT GO AS HIGH SINCE THE GFS IS THE ONLY MODEL SHOWING THIS FEATURE. SINCE THIS IS A SYNOPTIC FEATURE...HAVE WENT WITH SNOW TO WATER RATIOS NEAR 10 TO 1...WHICH RESULTS UP TO AN INCH OF SNOWFALL.

AFTER THE SYNOPTIC SNOWFALL PASSES...COLDER 850MB TEMPS SEEN UPSTREAM MOVE IN (SHOWN TO COOL TO -10 TO -12C). WITH LAKE TEMPERATURES AROUND 4C...ENOUGH INSTABILITY SHOULD BE PRESENT TO GENERATE LAKE EFFECT SNOW SHOWERS. HOWEVER...SUBSIDENCE BEHIND THE UPPER LEVEL TROUGH...ALONG WITH ADVECTION OF DRIER AIR IN OVER THE PLAINS MAY HINDER THE LAKE EFFECT PRECIPITATION PRODUCTION. MODELS...EVEN HIGHER RESOLUTION RUNS...REFLECT THIS BY SHOWING VERY LITTLE IN THE WAY OF QPF. HAVE STILL KEPT AMOUNTS ON THE HIGH END OF THE MODELS FOR BOTH TONIGHT AND TOMORROW...ESPECIALLY SINCE THERE ARE HINTS OF LAND BREEZES DEVELOPING TONIGHT THAT MAY HELP TO FOCUS AREAS OF CONVERGENCE. NONETHELESS...QPF AND SNOW AMOUNTS WERE NEARLY CUT IN HALF FROM THE PREVIOUS FORECAST GIVEN THE DRIER...LOWER INVERSION LOOK TO SOUNDINGS. GIVEN WNW FLOW...THE LAKE EFFECT SHOULD MAINLY BE CONFINED TO THE WESTERN U.P. AND LOCATIONS EAST OF MARQUETTE. AWAY FROM THE LAKE EFFECT SNOW...DRY CONDITIONS SHOULD PREVAIL AS THE SURFACE HIGH PRESSURE RIDGE OVER THE PLAINS ATTEMPTS TO BUILD INTO THE CWA ON MONDAY.

.LONG TERM (MONDAY NIGHT THROUGH NEXT SUNDAY)...

GFS SHOWING THE 500 MB TROUGH AXIS TO THE EAST 00Z TUE WITH RIDGING IN THE WEST AND THIS RIDGING POKES INTO THE CWA ON WED. GFS SHOWS SOME ISENTROPIC LIFT AND MOISTURE ON I280K-I290K SURFACES 12Z WED WITH A WARM FRONT MOVING THROUGH THE AREA AND MOISTURE IS QUITE DEEP. HAVE BEEN WATCHING THIS THE PAST FEW DAYS AND HAVE BEEN WONDERING IF POPS SHOULD BE IN FOR WED. WILL PUT SOME LOW CHANCE POPS IN AS THE WARM FRONT PASSES ACROSS THE AREA. GFS IS SHOWING 850-500 MB Q-VECTOR CONVERGENCE MOVING ACROSS FOR WED. LAKE MICHIGAN LAKE EFFECT ALSO ENTERS INTO THE PICTURE FOR WED AFTERNOON WITH LAKE MICHIGAN TEMPERATURES RUNNING AROUND 5C AND GFS 850 MB TEMPERATURES -8C TO -10C WHICH IS ENOUGH FOR LAKE ENHANCEMENT ANYWAY WITH SOUTH WINDS. WILL GO HIGH CHANCE POPS ALONG THE BAY OF GREEN BAY AND LAKE MICHIGAN SHORELINES TO ACCOUNT FOR THIS.

LAKE EFFECT WILL BE THE PROBLEM FOR THIS FORECAST. GFS BUFKIT SOUNDINGS FOR KIWD...KCMX AND KMQT SHOW INVERSION HEIGHTS OF 3000-4000 FEET MON NIGHT AND TUE WHILE KERY BUFKIT SOUNDING HAS INVERSION HEIGHT 5000 FEET MON NIGHT AND TUE. ALL SOUNDINGS THOUGH HAVE AN INVERTED-V LOOK AT THE LOW LEVELS WHICH IS SHOWING SOME DRY AIR WHICH COULD BE A PROBLEM. IT WILL BE COLD ENOUGH FOR LAKE EFFECT WITH 850 MB TEMPERATURES OFF THE GFS DOWN TO -14C TO -16C WHICH COMBINED WITH THE LAKE SUPERIOR TEMPERATURE OF 3C TO 4C...IS ENOUGH LAKE-850 MB DELTA-T FOR LAKE EFFECT. THINKING RIGHT NOW IS THAT THIS EVENT WILL MEET ADVISORY CRITERIA TO THE WEST AND EAST OF MARQUETTE IN THE WEST AND NORTHWEST FAVORED LAKE EFFECT SNOW BELT AREAS AND WILL NOT PUT UP ANY WATCHES AT THIS TIME AS DRY AIR IN LOW LEVELS IS STILL TROUBLING. WHEN THE INVERTED-V SOUNDINGS HAVE HAPPENED IN THE PAST...SNOWFALL AMOUNTS ARE LESS AND SNOWFALL RATIONS ALSO TEND TO BE LESS. WILL HIGHLIGHT THIS POSSIBILITY IN THE HWO. THINKING THAT SNOWFALL AMOUNTS WILL BE UP TO 9 INCHES FOR MONDAY NIGHT THROUGH TUESDAY FOR NOW AND THIS WOULD BE SPREAD OUT THROUGH 24 HOURS.

FOR TEMPERATURES...WENT CLOSE TO ADJMVR WHICH THEY SEEMED REASONABLE. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST.

IN THE EXTENDED...GFS...ECMWF SHOW THE 500 MB PATTERN CONSISTS OF A TROUGH IN THE WESTERN U.S. AND RIDGING OVER THE ERN HALF OF THE U.S. 00Z THU. TROUGHING PUSHES FURTHER EAST 00Z FRI INTO THE NORTHERN PLAINS WITH CWA ON PERIPHERY OF RIDGE. TROUGHING STILL REMAINS OFF TO THE WEST AND NORTHWEST FOR 00Z SAT AND THE TROUGH CONTINUES TO STAY TO THE WEST THROUGH SUN. LOOKS LIKE THIS WILL BE A LAKE EFFECT EXTENDED FORECAST TO DEAL WITH WITH NORTH TO NORTHWEST WINDS DURING THE PERIOD AND COLDER AIR COMING ACROSS THE LAKE. THIS OCCURS ALMOST EVERY PERIOD...SO WILL GO WITH CHANCE POPS EXCEPT OVER THE FAR SOUTH WHERE IT SHOULD BE DRY EXCEPT FOR THU AND THU NIGHT WITH A CLIPPER TYPE SYSTEM MOVING THROUGH. FOR TEMPERATURES...WENT CLOSE TO ADJENS AND ADJMXR FOR TEMPERATURES WHICH ARE NOT AS COLD AS PREVIOUSLY THOUGHT AND EXTENDED IS NOT LOOKING AS COLD AS IT WAS YESTERDAY. TEMPERATURES STILL LOOK TO BE NEAR NORMAL THOUGH FOR THE MOST PART.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...NONE. &&

$$

AJ (SHORT TERM) MICHELS (LONG TERM)

.SYNOPSIS... 20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED AN UPPER LEVEL TROUGH EXTENDING FROM THE UPPER MISSISSIPPI VALLEY INTO THE CENTRAL PLAINS...SITUATED BETWEEN RIDGES OVER THE EAST PACIFIC AND EASTERN U.S.. WITHIN THE TROUGH...SHRTWVS TO NOTE WERE OVER SE MINNESOTA AND ALONG THE MINNESOTA/DAKOTAS BORDER. DPVA AHEAD OF BOTH OF THESE SHRTWVS...COMBINED WITH PLENTY OF MOISTURE SEEN ON THE 12Z INL SOUNDING AND A 17Z TAMDAR SOUNDING FROM BRAINERD...HAS HELPED SUPPORT AN AREA OF LIGHT SNOW ACROSS MUCH OF DULUTHS FORECAST AREA. SOME OF THIS LIGHT SNOW HAS ALREADY SPREAD INTO THE WESTERN U.P. PER LOWER VISIBILITIES SEEN AT IWD AND CMX. DRIER AIR TO THE EAST AS SEEN ON THE 16Z SAWYER TAMDAR SOUNDING...COMBINED WITH SUNSHINE FILTERED THROUGH HIGH CLOUDS AND BREEZY SOUTHERLY WINDS HAVE ALLOWED TEMPERATURES TO CLIMB INTO THE UPPER 30S...WITH EVEN A FEW LOW 40S READINGS IN DOWNSLOPE AREAS. LOOKING AHEAD INTO THE FORECAST...IT WILL LIKELY BE A WHILE BEFORE WE SEE THESE READINGS AGAIN. AT THE SURFACE....1000MB LOW PRESSURE WAS SITUATED NEAR PICKLE LAKE WITH A COLD FRONT EXTENDING SOUTHWARD TO NEAR DUBUQUE. 850MB TEMPS FALL NEARLY 5C BEHIND THIS FRONT...FROM THE PRESENT -4C READINGS TO AROUND -9C AS SEEN ON THE BRAINERD SOUNDING. TO THE WEST OF THIS COOLER AIR...A HIGH PRESSURE RIDGE WITH PLENTY OF DRY AIR (NOTED BY THE LACK OF CLOUD COVER AND PRECIPITABLE WATER OF 0.19 INCHES ON THE 12Z BIS SOUNDING) WAS LOCATED OVER THE PLAINS. FARTHER TO THE WEST...A SHRTWV CAN BE SEEN DROPPING THROUGH ALBERTA...WITH AN ASSOCIATED 995MB LOW PRESSURE SITUATED OVER WEST CENTRAL ALBERTA.

&&

.SHORT TERM (TONIGHT AND MONDAY)...

UPPER LEVEL TROUGH OVER MINNESOTA WILL CROSS MOST OF UPPER MICHIGAN TONIGHT...ALONG WITH THE TWO SHRTWVS. DPVA AHEAD OF THESE SHRTWVS...COMBINED WITH ADVECTION OF MOISTURE FROM NORTHERN MINNESOTA SHOULD ALLOW FOR A TRANSLATION EASTWARD OF THE SNOW OVER DULUTHS AREA ACROSS THE CWA. THE 12Z GFS...WHICH HAS HAD AN EXCELLENT HANDLE ON THE SNOW SO FAR ALSO PRESENTS THIS IDEA...AND THEREFORE HAVE FOLLOWED MOST OF IT FOR THE FORECAST. THEREFORE... HAVE INCREASED POPS TO LIKELY AS THE SYNOPTIC SNOWFALL MOVES ACROSS. IT SHOULD BE NOTED THAT THE GFS SHOWS AN INCREASE OF 700MB OMEGA OVER THE CENTRAL U.P. AT 00Z THIS EVENING...WHICH RESULTS IN THE MODEL PRODUCING AROUND A TENTH OF AN INCH OF QPF. BECAUSE OF THIS...HAVE TRENDED QPF AMOUNTS UPWARDS...BUT DID NOT GO AS HIGH SINCE THE GFS IS THE ONLY MODEL SHOWING THIS FEATURE. SINCE THIS IS A SYNOPTIC FEATURE...HAVE WENT WITH SNOW TO WATER RATIOS NEAR 10 TO 1...WHICH RESULTS UP TO AN INCH OF SNOWFALL.

AFTER THE SYNOPTIC SNOWFALL PASSES...COLDER 850MB TEMPS SEEN UPSTREAM MOVE IN (SHOWN TO COOL TO -10 TO -12C). WITH LAKE TEMPERATURES AROUND 4C...ENOUGH INSTABILITY SHOULD BE PRESENT TO GENERATE LAKE EFFECT SNOW SHOWERS. HOWEVER...SUBSIDENCE BEHIND THE UPPER LEVEL TROUGH...ALONG WITH ADVECTION OF DRIER AIR IN OVER THE PLAINS MAY HINDER THE LAKE EFFECT PRECIPITATION PRODUCTION. MODELS...EVEN HIGHER RESOLUTION RUNS...REFLECT THIS BY SHOWING VERY LITTLE IN THE WAY OF QPF. HAVE STILL KEPT AMOUNTS ON THE HIGH END OF THE MODELS FOR BOTH TONIGHT AND TOMORROW...ESPECIALLY SINCE THERE ARE HINTS OF LAND BREEZES DEVELOPING TONIGHT THAT MAY HELP TO FOCUS AREAS OF CONVERGENCE. NONETHELESS...QPF AND SNOW AMOUNTS WERE NEARLY CUT IN HALF FROM THE PREVIOUS FORECAST GIVEN THE DRIER...LOWER INVERSION LOOK TO SOUNDINGS. GIVEN WNW FLOW...THE LAKE EFFECT SHOULD MAINLY BE CONFINED TO THE WESTERN U.P. AND LOCATIONS EAST OF MARQUETTE. AWAY FROM THE LAKE EFFECT SNOW...DRY CONDITIONS SHOULD PREVAIL AS THE SURFACE HIGH PRESSURE RIDGE OVER THE PLAINS ATTEMPTS TO BUILD INTO THE CWA ON MONDAY.

.LONG TERM (MONDAY NIGHT THROUGH NEXT SUNDAY)...

GFS SHOWING THE 500 MB TROUGH AXIS TO THE EAST 00Z TUE WITH RIDGING IN THE WEST AND THIS RIDGING POKES INTO THE CWA ON WED. GFS SHOWS SOME ISENTROPIC LIFT AND MOISTURE ON I280K-I290K SURFACES 12Z WED WITH A WARM FRONT MOVING THROUGH THE AREA AND MOISTURE IS QUITE DEEP. HAVE BEEN WATCHING THIS THE PAST FEW DAYS AND HAVE BEEN WONDERING IF POPS SHOULD BE IN FOR WED. WILL PUT SOME LOW CHANCE POPS IN AS THE WARM FRONT PASSES ACROSS THE AREA. GFS IS SHOWING 850-500 MB Q-VECTOR CONVERGENCE MOVING ACROSS FOR WED. LAKE MICHIGAN LAKE EFFECT ALSO ENTERS INTO THE PICTURE FOR WED AFTERNOON WITH LAKE MICHIGAN TEMPERATURES RUNNING AROUND 5C AND GFS 850 MB TEMPERATURES -8C TO -10C WHICH IS ENOUGH FOR LAKE ENHANCEMENT ANYWAY WITH SOUTH WINDS. WILL GO HIGH CHANCE POPS ALONG THE BAY OF GREEN BAY AND LAKE MICHIGAN SHORELINES TO ACCOUNT FOR THIS.

LAKE EFFECT WILL BE THE PROBLEM FOR THIS FORECAST. GFS BUFKIT SOUNDINGS FOR KIWD...KCMX AND KMQT SHOW INVERSION HEIGHTS OF 3000-4000 FEET MON NIGHT AND TUE WHILE KERY BUFKIT SOUNDING HAS INVERSION HEIGHT 5000 FEET MON NIGHT AND TUE. ALL SOUNDINGS THOUGH HAVE AN INVERTED-V LOOK AT THE LOW LEVELS WHICH IS SHOWING SOME DRY AIR WHICH COULD BE A PROBLEM. IT WILL BE COLD ENOUGH FOR LAKE EFFECT WITH 850 MB TEMPERATURES OFF THE GFS DOWN TO -14C TO -16C WHICH COMBINED WITH THE LAKE SUPERIOR TEMPERATURE OF 3C TO 4C...IS ENOUGH LAKE-850 MB DELTA-T FOR LAKE EFFECT. THINKING RIGHT NOW IS THAT THIS EVENT WILL MEET ADVISORY CRITERIA TO THE WEST AND EAST OF MARQUETTE IN THE WEST AND NORTHWEST FAVORED LAKE EFFECT SNOW BELT AREAS AND WILL NOT PUT UP ANY WATCHES AT THIS TIME AS DRY AIR IN LOW LEVELS IS STILL TROUBLING. WHEN THE INVERTED-V SOUNDINGS HAVE HAPPENED IN THE PAST...SNOWFALL AMOUNTS ARE LESS AND SNOWFALL RATIONS ALSO TEND TO BE LESS. WILL HIGHLIGHT THIS POSSIBILITY IN THE HWO. THINKING THAT SNOWFALL AMOUNTS WILL BE UP TO 9 INCHES FOR MONDAY NIGHT THROUGH TUESDAY FOR NOW AND THIS WOULD BE SPREAD OUT THROUGH 24 HOURS.

FOR TEMPERATURES...WENT CLOSE TO ADJMVR WHICH THEY SEEMED REASONABLE. OVERALL...DID NOT MAKE TOO MANY CHANGES TO THE GOING FORECAST.

IN THE EXTENDED...GFS...ECMWF SHOW THE 500 MB PATTERN CONSISTS OF A TROUGH IN THE WESTERN U.S. AND RIDGING OVER THE ERN HALF OF THE U.S. 00Z THU. TROUGHING PUSHES FURTHER EAST 00Z FRI INTO THE NORTHERN PLAINS WITH CWA ON PERIPHERY OF RIDGE. TROUGHING STILL REMAINS OFF TO THE WEST AND NORTHWEST FOR 00Z SAT AND THE TROUGH CONTINUES TO STAY TO THE WEST THROUGH SUN. LOOKS LIKE THIS WILL BE A LAKE EFFECT EXTENDED FORECAST TO DEAL WITH WITH NORTH TO NORTHWEST WINDS DURING THE PERIOD AND COLDER AIR COMING ACROSS THE LAKE. THIS OCCURS ALMOST EVERY PERIOD...SO WILL GO WITH CHANCE POPS EXCEPT OVER THE FAR SOUTH WHERE IT SHOULD BE DRY EXCEPT FOR THU AND THU NIGHT WITH A CLIPPER TYPE SYSTEM MOVING THROUGH. FOR TEMPERATURES...WENT CLOSE TO ADJENS AND ADJMXR FOR TEMPERATURES WHICH ARE NOT AS COLD AS PREVIOUSLY THOUGHT AND EXTENDED IS NOT LOOKING AS COLD AS IT WAS YESTERDAY. TEMPERATURES STILL LOOK TO BE NEAR NORMAL THOUGH FOR THE MOST PART.

&&

.MQT WATCHES/WARNINGS/ADVISORIES... GALE WARNING EAST HALF LAKE SUPERIOR. &&

$$

AJ (SHORT TERM) MICHELS (LONG TERM)

.AVIATION(18Z-18Z)... LOW PRESSURE OVER WESTERN TENNESSEE WILL MOVE NORTHEAST TO NORTHEAST OHIO BY 06Z. MODELS IN AGREEMENT ON THIS. THE CEILING IN RAIN WILL START AS VFR AND THEN LOWER...WHILE THE VISIBILITY SHOULD QUICKLY GO TO MVFR AND THEN IFR. WE SHOULD GET A BREAK IN RAIN WHILE WE WAIT FOR SOME WRAP AROUND PRECIPITATION WHICH SHOULD BE MAINLY SNOW AFTER 05Z. THE TOL AND FDY AREAS MAY JUST GET BRUSHED WITH SOME RAIN AS THE MAIN IMPACT WILL BE THE EASTERN AREAS OF THE FORECAST REGION. THE FLOW WILL BE WESTERLY ON MONDAY SO ANY LAKE EFFECT WILL BE EAST OF CLEVELAND. CONDITIONS WILL BEGIN TO GO VFR EITHER LATE IN THE PERIOD OR AFTER 18Z EXCEPT IN EXTREME NORTHEAST OHIO AND NORTHWEST PA.

&&

.SHORT TERM(AFTERNOON UPDATE)... TEMPERATURES ARE SLOW TO RECOVER AS CLOUDINESS INCREASED AND THICKEN THROUGH THE MORNING. RAIN STARTING TO MOVE INTO SOUTHWEST OHIO AND TAKE A WHILE BEFORE MOVING INTO AREA THIS AFTERNOON WITH NW PA MAY NOT SEE RAIN UNTIL JUST AFTER SUNSET WHICH IS AT 5:05 PM. LATEST TAMDAR DATA INDICATED HIGH TEMPERATURES FROM 37 TO 42 DEGREES...AND ADJUSTED THE REGION IN THE UPPER 30S. &&

.SHORT TERM (TODAY THROUGH MONDAY NIGHT)... NICE JET ALOFT AND MOISTURE PLUME INCREASING FROM THE SOUTH. MID AND HIGH CLOUDS WILL BE INCREASING ACROSS WESTERN AND CENTRAL COUNTIES BY DAYBREAK WHICH WILL HELP TEMPER ANY FOG THAT IS DEVELOPING SO WILL REMOVE THREAT OF DENSE FOG ALTHOUGH SOME ISOLATED DENSE FOG NOT OUT OF THE QUESTION. WILL TAKE A WHILE TO SATURATE LOWER LAYERS AGAIN TODAY. WHILE GOOD JET DYNAMICS EXIST...DEEP GULF MOISTURE WILL NOT RETURN AND PCP WATER PROGGED TO REMAIN BELOW AN INCH. NONETHELESS...GROUND IS SATURATED AND WILL HAVE TO MONITOR RAINFALL POTENTIAL/AMOUNTS. FOR THE TIME BEING MOST MODELS ADVERTISING ABOUT A HALF INCH OR BELOW. WOULD NOT BE SURPRISED TO SEE A BIT MORE THAN THAT BUT WILL NOT ISSUE A FLOOD WATCH UNTIL I SEE A BETTER THREAT OF HEAVIER RAIN (3/4 INCH OR MORE). MODELS NOW IN CLOSER AGREEMENT ON TRACK AND STRENGTH OF SURFACE LOW PROGGED TO CROSS EASTERN OHIO SUNDAY NIGHT. NAM/WRF STILL FASTER WRAPPING IN COLDER AIR BEHIND LOW AND WILL COMPROMISE WITH WARMER GFS SOLUTION. RAIN MAY CHANGE TO SNOW AFTER MIDNIGHT NW OH AND BEFORE DAYBREAK MONDAY NE OH AND SHORTLY AFTER DAYBREAK NW PA ALTHOUGH PCPN WILL BE TRYING TO TAPER OFF AS COLDER AIR ARRIVES.

BARELY COLD ENOUGH TO SUPPORT SNOW MONDAY AND DRIER AIR WRAPPING IN SO WHILE THERE MAY BE SOME LAKE ENHANCEMENT MONDAY MORNING THERE SHOULD BE NO TRUE LAKE EFFECT. AIR DOES GET COLD ENOUGH FOR LAKE EFFECT LATER MONDAY AND A SMALL WINDOW OF OPPORTUNITY EXISTS FOR SOME SNOW BANDS TO DEVELOP. DO NOT WANT TO SOUND TOO SNOWY SINCE TEMPS WILL BE MARGINAL AND WIND WILL LIKELY BE BACKING FROM W TO SW AND THERE MAY BE SUBSIDENCE OCCURRING. WILL BACK OFF POPS MON AFTRN INTO MON EVENING TO CHANCE ACROSS THE SNOWBELT. WILL INCREASE POPS AGAIN MON NGT AS NEXT CLIPPER APPROACHES. WHILE IT SEEMS AS THOUGH EVERYONE WILL EVENTUALLY SEE SOME LIGHT SNOW I AM NOT SURE IT WILL ACCUMULATE MUCH. TRACK LOOKS PRETTY FAR SOUTH WITH LIMITED MOISTURE. CERTAINLY THERE IS THE OPPORTUNITY FOR AN INCH OR TWO THOUGH AND WILL HAVE TO TRY TO REFINE FCST AS EVENT GETS CLOSER.

GFS TEMP GUIDANCE WARMER THAN OTHER GUIDANCE TODAY AND SEEMS A CATEGORY TOO WARM AS CLOUDS WILL INCREASE AND RAIN DEVELOPS. PREFER WARMER TEMP GUIDANCE TNGT ACROSS THE EASTERN COUNTIES OR EVEN A CATEGORY ABV GUIDANCE AS TEMPS SHOULD HOLD UP UNTIL MON MORN WHEN COLDER AIR WRAPS IN. LITTLE TEMP RECOVERY MONDAY AS CAA CONTINUES.

&&

.LONG TERM(TUESDAY THROUGH SATURDAY)... EXTENDED FCST ON RECENT RUNS LOOKS RISKY BY NEXT WEEKEND AS NEXT COLD FRONT SAGS SOUTH AND WILL SEPARATE SOME TRUE ARCTIC AIR FROM SOME VERY MILD AIR. POSITION OF FRONT AND VARIOUS WAVES ON FRONT WHICH MAY DRIVE IT BACK NORTH OR SOUTH COULD MEAN THE DIFFERENCE FROM TEMPS NEAR FREEZING OR 40S/50S? WILL NOT MAKE ANY MAJOR CHANGES TO LONG TERM PORTION OF FCST AND LET DAY SHIFT LOOK AT NEW MODEL RUNS. YESTERDAYS LONG TERM DISCUSSION FOLLOWS...

A CLIPPER WILL MOVE THROUGH LATE MONDAY INTO TUESDAY AND THEN A LITTLE LAKE EFFECT SNOW. MODELS SEEM TO INDICATE A GOOD SLUG OF SNOW SHOWERS...WILL FORECAST SCATTERED SNOW SHOWERS. RIDGE BUILDS IN AND THEN A CHANCE LATE THURSDAY NIGHT INTO SATURDAY. TEMPERATURES SHOULD WARM THURSDAY NIGHT SO WILL KEEP IT RAIN. TEMPERATURES DON`T COOL OFF UNTIL SATURDAY NIGHT TO GET SOME SNOW. MODELS IN GENERAL AGREEMENT.

&&

.CLE WATCHES/WARNINGS/ADVISORIES... OH...VARIOUS RIVER FLOOD WARNINGS N CENTRAL AND NW OHIO. LE...GALE WARNING. PA...GALE WARNING.

&&

$$

SHORT TERM...KOSARIK/THOMPSON LONG TERM...KOSARIK/KIELTYKA AVIATION...KIELTYKA

.SHORT TERM(AFTERNOON UPDATE)... TEMPERATURES ARE SLOW TO RECOVER AS CLOUDINESS INCREASED AND THICKEN THROUGH THE MORNING. RAIN STARTING TO MOVE INTO SOUTHWEST OHIO AND TAKE A WHILE BEFORE MOVING INTO AREA THIS AFTERNOON WITH NW PA MAY NOT SEE RAIN UNTIL JUST AFTER SUNSET WHICH IS AT 5:05 PM. LATEST TAMDAR DATA INDICATED HIGH TEMPERATURES FROM 37 TO 42 DEGREES...AND ADJUSTED THE REGION IN THE UPPER 30S. && .AVIATION(12Z-12Z)... PATCHY DENSE FOG FOR A SHORT WHILE THIS MORNING. STREAMING HIGH CLOUDS AHEAD OF NEXT SYSTEM FOR LATER TODAY SHOULD AID IN A QUICK RETURN TO VFR. TOL/MFD THE LOWEST BUT EVEN THEY HAVE BEEN POPPING UP AND THEN DOWN THIS MORNING. SOME LAKE CLOUDS FOR POINTS EAST OF CLE THIS MORNING BUT THESE TOO SHOULD DISSIPATE QUICKLY THIS MORNING AS FLOW BECOMES INCREASINGLY ESE EVERYWHERE. RAIN TO ENTER THE PICTURE LATE IN THE DAY...AFT 5PM. THEN CONDITIONS GO DOWNHILL AGAIN. SYSTEM COMING UP FROM THE LOWER MISSISSIPPI VALLEY AND WITH IT A GOOD INFLUX OF MOISTURE. LOW WILL PASS RIGHT ACROSS NORTHEAST OHIO/NW PA. PERIODS OF RAIN WITH IFR CONDITIONS LIKELY IMMEDIATELY IN ADVANCE OF THE LOW. THEN ON THE BACKSIDE...BELIEVE IT OR NOT..PRECIP CHANGING OVER TO SNOW AFTER 04Z. CHANGEOVER PROBABLY WON`T MAKE IT TO POINTS EAST OF CLE BY 12Z MON THOUGH. THEN FOR MON MARGINAL TEMPS AND DECREASING MOISTURE MAY NOT MAKE IT THAT SNOWY AFTER ALL. &&

.SHORT TERM (TODAY THROUGH MONDAY NIGHT)... NICE JET ALOFT AND MOISTURE PLUME INCREASING FROM THE SOUTH. MID AND HIGH CLOUDS WILL BE INCREASING ACROSS WESTERN AND CENTRAL COUNTIES BY DAYBREAK WHICH WILL HELP TEMPER ANY FOG THAT IS DEVELOPING SO WILL REMOVE THREAT OF DENSE FOG ALTHOUGH SOME ISOLATED DENSE FOG NOT OUT OF THE QUESTION. WILL TAKE A WHILE TO SATURATE LOWER LAYERS AGAIN TODAY. WHILE GOOD JET DYNAMICS EXIST...DEEP GULF MOISTURE WILL NOT RETURN AND PCP WATER PROGGED TO REMAIN BELOW AN INCH. NONETHELESS...GROUND IS SATURATED AND WILL HAVE TO MONITOR RAINFALL POTENTIAL/AMOUNTS. FOR THE TIME BEING MOST MODELS ADVERTISING ABOUT A HALF INCH OR BELOW. WOULD NOT BE SURPRISED TO SEE A BIT MORE THAN THAT BUT WILL NOT ISSUE A FLOOD WATCH UNTIL I SEE A BETTER THREAT OF HEAVIER RAIN (3/4 INCH OR MORE). MODELS NOW IN CLOSER AGREEMENT ON TRACK AND STRENGTH OF SURFACE LOW PROGGED TO CROSS EASTERN OHIO SUNDAY NIGHT. NAM/WRF STILL FASTER WRAPPING IN COLDER AIR BEHIND LOW AND WILL COMPROMISE WITH WARMER GFS SOLUTION. RAIN MAY CHANGE TO SNOW AFTER MIDNIGHT NW OH AND BEFORE DAYBREAK MONDAY NE OH AND SHORTLY AFTER DAYBREAK NW PA ALTHOUGH PCPN WILL BE TRYING TO TAPER OFF AS COLDER AIR ARRIVES.

BARELY COLD ENOUGH TO SUPPORT SNOW MONDAY AND DRIER AIR WRAPPING IN SO WHILE THERE MAY BE SOME LAKE ENHANCEMENT MONDAY MORNING THERE SHOULD BE NO TRUE LAKE EFFECT. AIR DOES GET COLD ENOUGH FOR LAKE EFFECT LATER MONDAY AND A SMALL WINDOW OF OPPORTUNITY EXISTS FOR SOME SNOW BANDS TO DEVELOP. DO NOT WANT TO SOUND TOO SNOWY SINCE TEMPS WILL BE MARGINAL AND WIND WILL LIKELY BE BACKING FROM W TO SW AND THERE MAY BE SUBSIDENCE OCCURRING. WILL BACK OFF POPS MON AFTRN INTO MON EVENING TO CHANCE ACROSS THE SNOWBELT. WILL INCREASE POPS AGAIN MON NGT AS NEXT CLIPPER APPROACHES. WHILE IT SEEMS AS THOUGH EVERYONE WILL EVENTUALLY SEE SOME LIGHT SNOW I AM NOT SURE IT WILL ACCUMULATE MUCH. TRACK LOOKS PRETTY FAR SOUTH WITH LIMITED MOISTURE. CERTAINLY THERE IS THE OPPORTUNITY FOR AN INCH OR TWO THOUGH AND WILL HAVE TO TRY TO REFINE FCST AS EVENT GETS CLOSER.

GFS TEMP GUIDANCE WARMER THAN OTHER GUIDANCE TODAY AND SEEMS A CATEGORY TOO WARM AS CLOUDS WILL INCREASE AND RAIN DEVELOPS. PREFER WARMER TEMP GUIDANCE TNGT ACROSS THE EASTERN COUNTIES OR EVEN A CATEGORY ABV GUIDANCE AS TEMPS SHOULD HOLD UP UNTIL MON MORN WHEN COLDER AIR WRAPS IN. LITTLE TEMP RECOVERY MONDAY AS CAA CONTINUES.

&&

.LONG TERM(TUESDAY THROUGH SATURDAY)... EXTENDED FCST ON RECENT RUNS LOOKS RISKY BY NEXT WEEKEND AS NEXT COLD FRONT SAGS SOUTH AND WILL SEPARATE SOME TRUE ARCTIC AIR FROM SOME VERY MILD AIR. POSITION OF FRONT AND VARIOUS WAVES ON FRONT WHICH MAY DRIVE IT BACK NORTH OR SOUTH COULD MEAN THE DIFFERENCE FROM TEMPS NEAR FREEZING OR 40S/50S? WILL NOT MAKE ANY MAJOR CHANGES TO LONG TERM PORTION OF FCST AND LET DAY SHIFT LOOK AT NEW MODEL RUNS. YESTERDAYS LONG TERM DISCUSSION FOLLOWS...

A CLIPPER WILL MOVE THROUGH LATE MONDAY INTO TUESDAY AND THEN A LITTLE LAKE EFFECT SNOW. MODELS SEEM TO INDICATE A GOOD SLUG OF SNOW SHOWERS...WILL FORECAST SCATTERED SNOW SHOWERS. RIDGE BUILDS IN AND THEN A CHANCE LATE THURSDAY NIGHT INTO SATURDAY. TEMPERATURES SHOULD WARM THURSDAY NIGHT SO WILL KEEP IT RAIN. TEMPERATURES DON`T COOL OFF UNTIL SATURDAY NIGHT TO GET SOME SNOW. MODELS IN GENERAL AGREEMENT.

&&

.CLE WATCHES/WARNINGS/ADVISORIES... OH...VARIOUS RIVER FLOOD WARNINGS N CENTRAL AND NW OHIO. LE...GALE WARNING. PA...GALE WARNING.

&&

$$

SHORT TERM...KOSARIK/THOMPSON LONG TERM...KOSARIK/KIELTYKA AVIATION...OUDEMAN

.DISCUSSION... WINDS ARE THE PRIMARY CONCERN IN THE SHORT TERM...ALTHOUGH NOTHING SEEN TODAY WILL COMPARE TO WINDS EXPECTED ON MONDAY. FRONTAL ZONE WELL CLEAR OF CWA NOW...AND NW WINDS RUSHING IN. MAIN PRESSURE RISES NOW IN JAMES VALLEY OF AROUND 3HPA/3H... AND VARIETY OF OBS PLATFORMS SHOW ARND 40 KTS IN LOWER GATES. HOWEVER...SFC WINDS JUST NOT ABLE TO TAP FLOW ALFT AS HAVE HAD SOME CAA AT LOW LVLS THIS MORNING...WITH A BIT EXTRA DRAG FROM SNOWCOVER IN W. 1608Z TAMDAR SOUNDING FROM KSUX SHOWS EXACTLY THIS PROCESS...WITH UNDERCUTTING WEDGE OF COOLING LIMITING MIXING HEIGHT. THIS SNOWCOVER TO W ALSO LKLY TO LIMIT WHAT MIXING MIGHT OCCUR WITH INCREASED SUNSHINE...AS CLOUDS CLEAR SOMEWHAT MORE RAPIDLY W TO E. MOMENTUM TRANSFER SUGGEST THAT TOWARD E WHERE SOME BARE GROUND AND ALG/AHEAD OF PRESSURE RISES...MAY GET A COUPLE SPOTS TOWARD LOWER MO VLY INTO EARLY AFTN THAT TOUCH THE LOW END OF SUSTAINED 30 MPH...BUT DOES NOT SEEM WIDESPREAD ENOUGH TO WARRANT HOLDING ON TO ADVY. AFTER COLLABORATION...WL DROP THE SHORT TERM WIND ADVY...BUT HOLD ONTO YOUR HATS ON MONDAY. MUCH STRONGER WNDS APPEAR IN ORDER WITH LARGE SCALE SUBSIDENCE AND AGEOSTROPHIC SUPPORT TO SFC GRADIENT.

SEEDER FEEDER PROCESSES WOULD SEEM TO BE IMPORTANT TO EARLIER PRECIPITATION AND ONGOING AREA FROM AROUND KMML TOWARD KLYV... AS ONLY WHERE MID CLOUDS MOVING ACRS LOWER DECK SHOWING ANY ONGOING PCPN. WITH AREAS WELL ASSOCIATED WITH BACK EDGE OF UPR DIV Q SUPPORT...WL USE TO DEFINE DIMINISHING THREAT...WITH PERHAPS SMALL RISK OF MEASURABLE ACRS SW MN INTO MIDDAY.

PLAYED SOMEWHAT WITH NONDIURNAL TREND TO TMPS AS CONTINUED FALL RIGHT IN LOW LVL CAA ZONE. ALSO...WITH START OF STABILIZING WAA INTO W DURING AFTN OVER SNOWCOVER ALONG WITH ALBEDO EFFECT OF SUNSHINE ON SNOWCOVER...DROPPED TMPS BACK A BIT OVER W.

&&

.PREV DISCUSSION... CONTINUES TO LOOK LIKE A COUPLE WINDY DAYS FOR THE REGION. COLD FRONT CURRENTLY MOVING ACROSS CENTRAL SD WILL MOVE THROUGH SE SD THIS MORNING. WITH AND BEHIND THE FRONT...THERE HAVE BEEN SOME REPORTS OF 30 MPH SUSTAINED WINDS IN THE WEST. WILL SEE WINDS APPROACH 30 MPH SUSTAINED INTO THE WRN FSD CWA. DID ISSUE WIND ADVISORIES FOR TODAY...LARGELY FOR THE SAKE OF COLLABORATION...BUT WINDS DO LOOK MARGINAL EITHER WAY. BEST PRESSURE RISES WILL DRIVE THE WINDS IN THE WEST THIS MORNING...WHILE BETTER MIXING WILL BE THE DRIVING FORCE IN THE EAST LATER TODAY. DO EXPECT WINDS TO SLOWLY DROP IN THE WEST BY EARLY AFTERNOON...AND THEN BY EVENING IN THE EAST. OTHERWISE FOR TODAY...WILL LIKELY SEE SOME LIGHT SNOW SHOWERS ...MAINLY IN THE NORTH...BUT NOT ANTICIPATING ANY REAL ACCUMULATION.

TOMORROW WILL BE THE WINDIEST DAY...AS A QUICK MOVING LOW PRESSURE WILL DIVE SOUTH OUT OF CANADA TOMORROW MORNING AND ACROSS MINNESOTA IN THE AFTERNOON. A VERY TIGHT PRESSURE GRADIENT WILL LIKELY PRODUCE SUSTAINED WINDS OF 40 MPH THROUGH THE MISSOURI RIVER VALLEY...WITH GUSTS TO 55 MPH POSSIBLE. THE MAGNITUDE WILL BE LESS FARTHER N AND E...BUT TO WHAT EXTENT REMAINS A QUESTION...WILL LARGELY DEPEND ON THE EXACT TRACK OF THE SURFACE LOW. THERE WILL ALSO BE SOME LIGHT SNOW ON THE BACK SIDE OF THE LOW...MOST LIKELY INTO SW MN WHERE A COUPLE OF INCHES OF ACCUMULATION WILL BE POSSIBLE.

LOOKING INTO THE EXTENDED...LOOKS LIKE A MAJOR COOL DOWN BY THE END OF THE WEEK...WITH HIGH TEMPERATURES INTO THE TEENS BY WEEKS END...AND INTO THE WEEKEND.

&&

.AVIATION... LINGERING MVFR CIGS INTO EARLY AFTN ACRS TWB243 AND ERN PORTIONS OF TWB302...BUT WL BE ENDING BY 20-21Z AS CLEARING W OF INTERSTATE 29 AT 16Z MOVES STEADILY EWRD...WITH CLEARING ARND 18Z AT KFSD...AND SHORTLY BEFORE 19Z AT KSUX. SOME MVFR CIGS PSBL FOR KHON FROM 08Z-12Z AND KFSD 10Z-14Z WITH NARROW FRONTAL BAND OF POTENTIAL SNOWFALL...WHICH WL BE MORE LKLY HEADING EWRD THRU TWB243.

BIG CONCERN FOR END OF 18Z TAF PERIOD IS WIND. 16Z-18Z PD LOOKS VERY LIKELY TO SEE SIG INCREASE IN WIND SPEED. STRONGER WNDS WL BE JUST AFTER VALID TAF PD...LKLY SUSTAINED OVER 35 KTS WITH GUSTS TOWARD 50 KTS FOR KSUX.

&&

.FSD WATCHES/WARNINGS/ADVISORIES... SD...HIGH WIND WATCH LATE MONDAY MORNING THRU EARLY MONDAY EVENING FOR SDZ050-057-058-063-064-065-068>071. MN...NONE. IA...HIGH WIND WATCH LATE MONDAY MORNING THRU EARLY MONDAY EVENING IAZ031. NE...HIGH WIND WATCH LATE MONDAY MORNING THRU EARLY MONDAY EVENING NEZ013-014.

&&

$$

CHAPMAN/LIEBL/GH

.SHORT TERM (TONIGHT THROUGH TUESDAY)... WATER VAPOR LOOP SHOWS A LONG WAVE TROUGH ACROSS THE NORTH CENTRAL CONUS...WITH EMBEDDED WAVES MOVING EAST ACROSS THE TENNESSEE VALLEY AND SOUTHEAST ACROSS THE MIDWEST. ACARS 400-250MB WIND OBSERVATIONS REVEAL 140-180KT WINDS ROUND THE AFOREMENTIONED TROUGH. 04Z SURFACE ANALYSIS PLACED A TROUGH IN THE LEE OF THE APPALACHIANS. A COLD FRONT WAS CROSSING CHICAGO AND SAINT LOUIS...WITH A SECOND TRAILING COLD FRONT SINKING SOUTH THROUGH THE UPPER MIDWEST.

A CLEAR START TO THE DAY WILL QUICKLY DETERIORATE WITH THE APPROACH OF A STRONG SHORTWAVE. THE VERTICAL MOTION COUPLET OF THE WAVE ACROSS SOUTHERN ILLINOIS HAS BEEN INCREASINGLY MORE IMPRESSIVE THROUGH THE NIGHT ON WATER VAPOR IMAGERY. GFS/NAM IN AGREEMENT THAT THIS WAVE FEEDING INTO THE LONGWAVE TROUGH WILL ALLOW THE TROUGH TO BECOME NEGATIVE TILTED BEGINNING LATE TODAY...CAUSING SIGNIFICANT CYCLOGENESIS OFFSHORE TONIGHT. DEEP LAYER LAPSE RATES BETWEEN 1000MB AND 500MB ARE FORECAST TO BE STEEP...NEAR 7.5C/KM. GIVEN THE SYNOPTIC SITUATION...AM CONCERNED THAT VERTICAL MOTION CAUSED BY THE SHORT WAVE LATE THIS AFTERNOON MAY BE ENOUGH TO ALLOW A 1-2 HOUR SNOW SHOWER BURST. WITH TEMPERATURES REACHING INTO THE MID 40S...NO ACCUMULATION IS EXPECTED EAST OF THE MOUNTAINS...HOWEVER THERE MAY BE A SOCIETAL IMPACT WITH THE FIRST POSSIBILITY OF FLAKES ACROSS THE GREATER WASHINGTON METRO AREA (CLOSE TO EVENING RUSH HOUR).

OF COURSE THERE WILL BE A CHALLENGE TO SEE SNOW FLAKES THIS AFTERNOON AFTER HIGHS IN THE MID 40S (A BIT COOLER THAN MOS GIVEN RAPID INCREASE IN CLOUDS EXPECTED THIS MORNING). 0C HEIGHT IS JUST OFF THE SURFACE AT 2KFT. DRY AIRMASS (PRECIPITABLE WATER VALUE OF 0.19 AT 00Z KIAD RAOB) WILL ALLOW EVAPOARATIONAL COOLING. DYNAMICAL COOLING MAY BE A SIGNIFICANT FACTOR WITH IMPRESSIVE VERTICAL MOTION SHOWN BY THE NAM DURING THE LATE AFTERNOON. THIS VERTICAL MOTION IS WITHIN THE DENDRITIC SNOW GROWTH RANGE...WHICH WOULD FAVOR LARGE DENDRITE FORMATION WITHIN THE CLOUD LAYER (WITH A SHORT TRIP WITHIN THE WARM SUB-CLOUD LAYER TO THE GROUND). THERE IS ALSO INDICATION OF FRONTOGENESIS IN THE 700-850MB LAYER AS THE SYSTEM BEGINS TO DEEPEN...WHICH WOULD SUPPORT PRECIPITATION DEVELOPMENT EAST OF THE MOUNTAINS.

THERE IS LESS UNCERTAINTY ALONG THE WESTERN SLOPES OF THE MOUNTAINS WHERE TEMPERATURES ARE ALREADY SUPPORTIVE OF SNOW...AND IN FACT SNOW HAS ALREADY BEEN REPORTED AT KEKN AS OF 09Z. BEHIND THE WARM ADVECTION AND LEADING EDGE OF THE COLD ADVECTION PRECIPITATION...UPSLOPE SNOW WILL PERSIST THROUGH THE NIGHT...AS THE SKY EAST OF THE MOUNTAINS BECOMES MOSTLY CLEAR TO PARTLY CLOUDY. HAVE ISSUED A SNOW ADVISORY WITH 03Z SHORT RANGE ENSEMBLES AT KEKN INDICATING A MEAN OF 0.37" OF SNOW LIQUID EQUIVALENT THROUGH 12Z EARLY WEDNESDAY MORNING...AND A MAX OF 0.85". CURRENT SNOW FORECAST IN THE MOUNTAINS IS 1-3" TODAY AND 1-2" TONIGHT. WIND GUSTS OF 35 MPH ACROSS THE REGION TONIGHT WILL ALLOW WIND CHILLS TO NEAR ZERO ACROSS THE HIGHER TERRAIN LATE TONIGHT.

&&

.AVIATION... STRONG WAVE WILL ALLOW UPPER TROUGH TO GO NEGATIVE TILT BEGINNING LATE THIS AFTERNOON. MID LEVEL CLOUDS WILL MOVE IN DURING THE MORNING. THERE COULD BE A BRIEF SHOT OF IFR CLOUDS/VISIBILITIES WITH RAIN/SNOW SHOWERS ASSOCIATED WITH THE LEADING EDGE OF THE COLD ADVECTION. NORTHWEST DOWNSLOPE FLOW WILL DEVELOP BY EVENING AND ALLOW MUCH OF THE CLOUDS TO DISSIPATE.

&&

.MARINE... 00Z GFS/ETA MOS AT THOMAS POINT BOTH SUGGEST SUSTAINED WINDS WILL BE IN THE 10-15KT RANGE TODAY...AND 15-20KT RANGE TONIGHT. 00Z NAM PROXIMITY LAND BUFKIT FORECAST SOUNDINGS SUGGEST ADDITIONAL WIND GUST MOMENTUM OF 20 KNOTS BETWEEN 14-20Z...WHILE THE 00Z GFS INDICATES GUSTS BETWEEN 18-22 KNOTS. BOTH THE 00Z NAM AND GFS INDICATE 30KT WIND GUSTS THIS EVENING AND TONIGHT BEHIND THE COLD FRONT. SINCE THE LULL IS ONLY SEVERAL HOURS...WILL HAVE ONE SMALL CRAFT ADVISORY BEGINNING AT 14Z TODAY.

IN NW FLOW STRONG SCA WINDS ARE LIKELY TO CONTINUE ON WED. HAVE EXTENDED THE PREVIOUSLY ISSUED SCA INTO WEDNESDAY. WINDS WILL QUICKLY DIMINISH WED EVNG AS HIGH MOVES INTO THE MID ATLC.

&&

.TIDES... WATER LEVELS ARE CURRENTLY A QUARTER FOOT BELOW ASTRONOMIC PREDICTIONS. THE LUNAR CYCLE IS WANING FROM A FULL MOON (71% FULL). BLOWOUT CONDITIONS WERE EXPERIENCED YESTERDAY BEHIND THE COLD FRONT. THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM FORECASTS WATER LEVELS TO RECOVER TO PREDICTED LEVELS AGAIN TODAY...WHILE THE NOAA EXTRATROPICAL STORM SURGE MODEL IS CURRENTLY OVER-FORECASTING WATER LEVELS.

&&

.LONG TERM...WEDNESDAY THROUGH MONDAY...

UPSLOPE SNOW SHWRS SHOULD COME TO AN END BY MIDDAY WED AS UPPER TROUGH SWINGS TO THE E AND TRAJECTORIES BECOME LESS FAVORABLE OFF THE GRT LKS. HWVR COLDEST TEMPS ALOFT PERSIST THROUGH THE DAY WED. WILL INDICATE A STRONG TOPOGRAPHICAL EFFECT ON WED WITH TEMPS IN THE HIGHER TERRAIN ONLY IN THE LOWER TO MID 20S. WED NGT THE FLOW REGIME BEGINS TO BACK TO SW...THOUGH THE WARMING TREND WILL BE VERY SLOW THROUGH THE END OF THE WEEK. SFC HIGH MOVES OFFSHORE BY FRIDAY AND WARMER TEMPS SURGE N AS A RESULT. MAX TEMPS FRI-SUN WILL WARM WELL INTO THE 50S TO AROUND 60 IN THE SE CWFA (DURING THE COLDEST TIME OF THE YR...THESE TEMPS WILL BE NEARLY 20 DEG ABOVE NORMAL).

WED NGT THROUGH FRI WILL REMAIN A DRY FCST WITH HIGH PRES SLOWLY MOVING OFF THE CST.

WARM SECTOR FOR MUCH OF THE WKEND. HAVE BACKED POPS DOWN JUST A HAIR SAT-SUN WITH THE BEST CHCS RELEGATED TO W OF THE BL RIDGE. ATTM IT REALLY DOESN`T LOOK LIKE MUCH PRECIP SHOULD REACH THE I-95 CORRIDOR TIL SUN NGT WITH THE APPROACH OF A STRONG COLD FRONT. EXCELLENT RIBBON OF LIFT IN CONJ WITH THE FRONT LATE SUN NGT AND MON...WILL INDICATE 40 POPS DURING THIS GENERAL TIMEFRAME. WILL HOLD ON TO THE COOLER TEMPS BEHIND THE FRONT MON AND ESP ON TUE.

&&

.LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...SNOW ADVISORY FROM 10 AM THIS MORNING TO 4 AM EST WEDNESDAY FOR MDZ501.

VA...SNOW ADVISORY FROM 10 AM THIS MORNING TO 4 AM EST WEDNESDAY FOR VAZ021.

WV...SNOW ADVISORY FROM 10 AM THIS MORNING TO 4 AM EST WEDNESDAY FOR WVZ054-501-503.

MARINE...SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 6 PM EST WEDNESDAY FOR ANZ530>537.

&&

$$

SHORT TERM/HYDROLOGY/AVIATION/TIDES...ROGOWSKI LONG TERM...BROTHERTON MARINE...ROGOWSKI/BROTHERTON

.UPDATE #2... HAVE ISSUED AN UPDATE TO THE PUBLIC AND MARINE FCSTS AND ALL ASSOCIATED GRIDDED PRODUCTS THIS MORNING FOR SEVERAL REASONS. FIRST, HAVE REMOVED TEMPORAL REFERENCES TO MORNING. SECOND, HAVE MADE SOME ADJUSTMENTS TO CLOUD COVER BASED ON CURRENT AND EXPECTED SATELLITE TRENDS. MOST OF THE REGION ALREADY HAS A BKN MID-LEVEL DECK, SO WILL JUST GO WITH MOSTLY CLOUDY IN THESE AREAS AND INCREASING CLOUDINESS ELSEWHERE FOR BREVITY. THIRD, ADJUSTED SOME WINDS, MAINLY ON THE MARINE.

MOST IMPORTANTLY, BASED ON SOME CURRENT ACARS SOUNDINGS THAT HAVE THE FREEZING LEVEL AOA 2000 FEET AND HIGH TEMPERATURES CURRENTLY FCST TO BE IN THE 40S IN MOST LOCATIONS, HAVE OPTED TO REMOVE ALL REFERENCES TO SNOW SHOWERS OR FLURRIES FOR ALL BUT THE NWRN ZONES, WHERE TEMPS WILL BE COOLER AND ELEVATION ALSO COMES INTO PLAY.

&&

.UPDATE #1... /ISSUED 625 AM TUE JAN 9 2007/ UPDATED THE CWF TO DROP THE ONGOING SCA FLAG FOR THE WATERS. SEAS AT 44009 HAVE DECREASED TO 4 FT AND THERE ARE ONLY A FEW G25 OVER THE WATERS ATTM. THE WINDS WILL SUBSIDE FURTHER THIS MORNING AS THEY VEER AROUND TO SW. I HAVE PLACED A NEW HAZARD GRID FOR THE NEXT EXPECTED SCA FLAG FOR TONIGHT. I HAVE STARTED IT AT 10 PM.

&&

.PREV DISCUSSION... /ISSUED 355 AM EST TUE JAN 9 2007/

SYNOPSIS... AFTER YESTERDAY`S COLD FRONTAL PASSAGE, A RETURN TO COLDER WEATHER HAS ARRIVED. HOWEVER, A BIT OF WARMING WILL TAKE PLACE TODAY AS A CLIPPER SYSTEM DIVES TO OUR SOUTH THIS AFTERNOON AND EVENING. BEHIND THIS FEATURE, A SHOT OF COLD AIR WILL INTRUDE THE REGION, HOWEVER THIS WILL BE TRANSIENT AS A MILDER TREND WILL GET UNDERWAY YET AGAIN FOR THE END OF THE WEEK AND WEEKEND. A RATHER ACTIVE FRONTAL SYSTEM WILL TAKE SHAPE FROM THE GREAT LAKES ALL THE WAY TO THE CENTRAL GULF COAST STATES. THIS ENTIRE FRONTAL FEATURE WILL SERVE AS A CONDUIT FOR SOME WAVES OF LOW PRESSURE AS COLDER AND COLDER AIR GETS PULLED SOUTHWARD INTO THE PLAINS. GRADUALLY IT APPEARS A TURN TO COLDER WEATHER IS IN OUR FUTURE BEYOND THIS UPCOMING WEEKEND, BUT AT THIS POINT IN TIME THE UNCERTAINTY OF THE COLD BECOMING LOCKED IN IS LOW.

SHORT TERM /TODAY THROUGH WEDNESDAY/... ALL IS RELATIVELY QUIET TO START THINGS OFF EARLY THIS MORNING, ALTHOUGH THE WINDS HAVE HELD UP IN MOST SPOTS SO FAR. TODAY WILL FEATURE THE ARRIVAL OF ANOTHER UPPER-LEVEL TROUGH WHICH WILL DRIVE A CLIPPER SYSTEM TO OUR SOUTH. WAA OCCURRING AHEAD OF THIS FEATURE IS EVIDENT BY THE BACKING FLOW ACROSS THE OHIO VALLEY ALONG WITH AN INCREASE IN CLOUDS. CLOUDS WILL BE ON THE INCREASE TODAY ACROSS THE CWA, MAINLY IN THE MID TO HIGH LEVEL KIND, ALTHOUGH MANY AREAS SHOULD BE ABLE TO SNEAK IN A GOOD DEAL OF SUNSHINE FIRST THING THIS MORNING. THE MAIN QUESTION TODAY REVOLVES AROUND PRECIPITATION CHANCES. WITH THE CLIPPER AND ASSOCIATED DYNAMICS TAKING A TRACK FURTHER TO OUR SOUTH, THIS IS NOT ALL THAT FAVOR FOR MOST OF OUR REGION. ALSO, THE 00Z RAOBS DEPICTED A RATHER DRY AIRMASS IN PLACE WHICH IS ALSO EVIDENT BY THE LOW DEWPOINTS WHICH ADVECTED IN LATE YESTERDAY.

FORECAST SOUNDINGS FROM AROUND THE REGION THROUGH TODAY SHOW INCREASING INSTABILITY ALOFT, SEEN BY THE TOTAL TOTALS RISING INTO THE 50S THIS AFTERNOON /AROUND 60 ACROSS THE DELMARVA/. NO QUESTION THERE IS DECENT AMOUNT COLD AIR ALOFT AIDING IN THE INSTABILITY, HOWEVER THE BULK OF THE LIFT WITH THE CLIPPER CRUISES TO OUR SOUTH WHICH LEAVES NOT MUCH FOR MOST OF OUR CWA. THE BEST CHC IS TARGETED ACROSS OUR DELMARVA ZONES /SUPPORT FROM BOTH THE GFS AND NAM/ AS THEY WILL BE CLOSER TO THE STRONG DYNAMICS /UPPER TROUGH TAKING ON SOMEWHAT OF A NEGATIVE TILT/, AND PERHAPS OUR WESTERN ZONES AS ANY ACTIVITY THAT TRIES TO FORM TO OUR WEST REACHES THERE BEFORE FALLING APART. EVEN THE HIGHER RESOLUTION NAM IS NOT ALL THAT EXCITED ABOUT PRECIPITATION CHCS/COVERAGE TODAY EXCEPT ACROSS THE DELMARVA, HOWEVER AM A LITTLE WEARY GIVEN SOME INSTABILITY ALOFT. IT SHOULD BE NOTED THAT THE STRONG DYNAMICS AND INSTABILITY WILL BE BATTLING A RATHER DRY SUB CLOUD LAYER. BUFKIT SOUNDINGS ACROSS THE DELMARVA INDICATE GOOD OMEGA NEAR THE DENDRITIC ZONE LATER THIS AFTERNOON AND EARLY THIS EVENING. THE BOUNDARY LAYER COULD BE A LITTLE TO WARM TO JUSTIFY SNOW, HOWEVER BASED ON THE COLDER TEMPERATURES ALOFT AND THAT THE 0C ISOTHERM IS FORECAST NEAR 2,000 FEET, WE WILL GO WITH CHC POPS /40-ISH/ ACROSS THE DELMARVA AND INDICATE RAIN AND SNOW SHOWERS. THE WESTERN ZONES WE WILL CARRY A 30-ISH POP FOR SNOW SHOWERS PERHAPS SOME RAINDROPS MIXED IN. ELSEWHERE, WE WILL CARRY THE POTENTIAL FOR SOME FLURRIES OR SPRINKLES BASED ON THE INSTABILITY ALOFT.

FOLLOWING THE PASSAGE OF THE CLIPPER SYSTEM AND UPPER-LEVEL TROUGH, A SURFACE LOW WILL DEVELOP OFF THE COAST TONIGHT. THE MODEL GUIDANCE SHOWS PRECIPITATION NOT TO FAR OFFSHORE, AND THIS SYSTEM SHOULD TAKE OFF GIVEN THE INCREASED BAROCLINICITY THAT WILL BE DEVELOPING AS EVEN COLDER AIR ALOFT MOVES OVER THE WARMER WATERS. WE WILL HOLD ONTO A 40-ISH POP ACROSS THE DELMARVA REGION FOR A FEW HOURS THIS EVENING AS THE CLIPPER SYSTEM MOVES THROUGH AND A SURFACE LOW ORGANIZES OFF THE COAST. A SHOT OF COLDER AIR WILL THEN SETTLE IN FOR TONIGHT AND WEDNESDAY. CLOUDS MAY TEND TO LINGER FOR AWHILE TONIGHT ALONG THE COAST /SURFACE LOW DEVELOPMENT/ AND ALSO THE NORTHWEST ZONES /LAKE INDUCED/. THE HIGHER RESOLUTION MODELS ARE NOT TO EXCITED ABOUT BRINGING LAKE EFFECT FLURRIES OR SNOW SHOWERS INTO THE POCONOS, HOWEVER WITH THE WEST TO NORTHWEST FLOW AND DEEPENING COLD AIR, WE WILL KEEP FLURRIES MENTIONED.

IT WILL BE TURNING RATHER BRISK TONIGHT AND ESPECIALLY WEDNESDAY WITH CAA, A TIGHTENING PRESSURE GRADIENT, AND FORECAST SOUNDINGS SHOW GOOD MIXING. AS A RESULT, WE HAVE BUMPED UP THE SUSTAINED WINDS AND GUSTS A LITTLE MORE ESPECIALLY ON WEDNESDAY.

USED THE MAV SURFACE DEWPOINTS FOR TODAY AS THE MET VALUES WERE ALREADY A LITTLE TO HIGH EARLY THIS MORNING. AS FOR TEMPERATURES, USED A BLEND OF THE MODEL GUIDANCE, WHICH DID NOT MAKE SIGNIFICANT CHANGES TO CONTINUITY.

LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... NO MAJOR CHANGES WERE MADE TO THIS TIME FRAME. AFTER OUR QUICK SHOT OF COLD AIR TONIGHT THROUGH WEDNESDAY NIGHT, LOOKING TO THE WEST SHOWS MUCH COLDER AIR PLUNGING INTO MONTANA AND THE DAKOTAS STARTING AROUND THURSDAY. THIS ARCTIC AIR SHOULD SLOWLY DRIFT SOUTHEASTWARD WITH TIME, STRENGTHENING A BAROCLINIC ZONE IN THE CENTRAL PART OF THE NATION. MOISTURE MOVING NORTHWARD WILL CAUSE SOME ISSUES FOR THE FOLKS IN THE PLAINS AND PARTS OF THE GREAT LAKES, HOWEVER WE WILL REMAIN ON THE WARM SIDE.

HIGH PRESSURE BUILDING IN WEDNESDAY NIGHT WILL ALLOW THE PRESSURE GRADIENT TO RELAX, SETTING UP A DECENT RADIATIONAL COOLING NIGHT. A POTENTIAL FLY IN THE OINTMENT REGARDING IDEAL RADIATIONAL COOLING CONDITIONS WILL BE THE WAA THAT IS FORECAST TO BE GETTING UNDERWAY WEDNESDAY NIGHT AT 850 MB. THIS MAY GENERATE SOME HIGH LEVEL CLOUDINESS FOR AT LEAST PARTS OF OUR CWA. BELOW IS THE DISCUSSION FROM YESTERDAY`S DAY SHIFT WITH SOME ADDITIONS HERE AND THERE.

FOR THURSDAY, WE KEPT MAXIMUM TEMPERATURES ABOVE GUIDANCE AS PER PLUS 0C 850 MB TEMPERATURES FORECAST FOR THE END OF THE DAY. THERE ARE MODEL DIFFERENCES WITH RESPECT TO THE PRECIPITATION CHCS TOWARD AND DURING THE WEEKEND. A COLD FRONT IS FORECAST TO APPROACH OUR CWA ON FRIDAY BUT NOT COME CLOSE ENOUGH TO INCLUDE CHCS FOR NOW FRIDAY DAY. THIS IS A COMPROMISE BETWEEN THE MORE AND LESS AGGRESSIVE MODEL SOLUTIONS. WE DID MAINTAIN SOME LOW CHCS MAINLY THE NORTHERN HALF OF OUR CWA FOR FRIDAY NIGHT. THE FRONT IS THEN FORECAST TO STALL NORTH OR NEAR OUR CWA ON SATURDAY AND WE WILL KEEP LOW CHC POPS IN THE SAME AREAS. BEST CHCS FOR PRECIPITATION WILL COME SUNDAY INTO MONDAY AS WAVY COLD FRONT MOVES ACROSS OUR CWA. WILL HAVE TO WATCH SURFACE LOW DEVELOPMENT ALONG THIS FRONT AS THAT WILL SLOW THE EASTWARD PROGRESSION, POTENTIALLY DELAYING THE MAIN PRECIPITATION SHIELD. ANY CHC FOR SNOW ATTM WILL DEPEND UPON HOW MANY MORE FUTURE WAVES THERE WILL BE ON THE SLOW MOVING FRONT BEYOND NEXT MONDAY. THIS IS THE PATTERN CHANGE COLD FRONTAL PASSAGE AND THE MODELS HAVE DIFFERED WITH RESPECT TO HOW QUICKLY THIS FRONT MOVES INTO AND CLEARS OUR CWA. THEREFORE CONFIDENCE ABOUT THE TIMING IS SLIGHTLY LOWER THAN NORMAL. WE DID LIKE HPC/S THOUGHTS OF GOING HIGHER THAN GUIDANCE ON THE WEEKEND FOR CONSISTENCY SAKE IF WE TRULY DO GET AND REMAIN IN THE WARM SECTOR.

LONG RANGE MODELS ARE TAKING THE ENTIRE BAROCLINIC ZONE AND SLIDING IT EASTWARD MARKING A CHANGE TO COLDER WEATHER IN THE EAST AFTER ABOUT JANUARY 16TH. THE PACIFIC EXPRESS TRAIN IS FORECAST TO BE DERAILED WITH STRONG RIDGING EXPECTED BY ALL THE MEDIUM RANGE MODELS IN THE EASTERN PACIFIC. THUS THE EPO TELECONNECTION INDEX IS FORECAST TO GO NEGATIVE, A FEATURE WE HAVE NOT SEEN WE BELIEVE SINCE LATE OCTOBER/EARLY NOVEMBER. THIS IS USUALLY A COLD INDICATOR FOR THE EAST. BUT IN OUR POND THE NAO IS FORECAST TO REMAIN POSITIVE, WHICH NORMALLY MEANS A MILDER REGIME. IT LOOKS AS THOUGH THE UNSEASONABLY WARM PATTERN WILL END FOR AWHILE AFTER THIS UPCOMING WEEKEND. HOW COLD IT GETS WILL DEPEND UPON HOW MUCH RIDGING EXTENDS INTO ALASKA AND WESTERN CANADA /OR FURTHER NORTH/ VERSUS REMAINING IN THE EASTERN PACIFIC. ONE QUESTION IS REGARDING THE EXTENT OF THE SOUTHEASTWARD INTRUSION OF THE COLDER AIR MAKING IT EAST OF THE APPALACHIANS. THE MORE RIDGING THAT GETS INTO THE WESTERN U.S. AND WESTERN CANADA, THE HIGHER THE AMPLITUDE TOWARD THE POLE, THUS THE COLDER THE SHOTS WILL BE HERE. IN ADDITION, THE STRENGTH OF THE SOUTHEASTERN RIDGE MAY BE THE KEY PLAYER ON WHERE THE TRUE BAROCLINIC ZONE BECOMES SITUATED DURING THE MIDDLE TO LATE PORTION OF THIS MONTH AS MOISTURE LOOKS TO LURK CLOSE BY. STAY TUNED.

AVIATION /09Z-06Z/... CLEAR SKIES AND GENTLE WEST WINDS OVER THE TAF SITES EARLY THIS MORNING. MID LEVEL CLOUDINESS IS INDICATED ON SATELLITE OVER THE OHIO VALLEY AND IT IS EXPECTED TO CONTINUE EASTWARD OVER OUR AREA THIS MORNING AND INTO THE AFTERNOON. I HAVE SPED UP THE TIMING OF THE ARRIVAL AND AMOUNT OF CLOUDS WHEN COMPARED TO THE PREVIOUS TAFS. WRF MODEL SHOWING SOME MINOR PRECIP SOUTH OF THE TAF SITES TODAY AND THE GFS ALSO PRODUCING SOME MINOR PRECIP MAINLY SOUTH THIS EVENING. I HAVE LEFT PRECIP OUT OF MY TAFS, SINCE THE AIRMASS IS VERY DRY AND THE MOS PROBS ARE LOW. SFC WINDS WILL BACK AROUND TO SW THIS MORNING AND REMAIN THERE MUCH OF THE DAY. SPEEDS WILL INCREASE TO AROUND 10 TO 15 KT. TONIGHT THE WINDS WILL VEER TO NW AND REMAIN MODERATE. CLOUDS ARE EXPECTED TO BREAK UP TONIGHT AS HIGH PRESSURE STARTS TO BUILD IN.

MARINE... LOOKS LIKE WE WILL BE ABLE TO TAKE THE SCA FLAG DOWN AT 12Z THIS MORNING. THE FLAG WON`T HAVE TO BE STOWED TOO FAR AWAY THOUGH AS IT WILL BE FLYING AGAIN TONIGHT. PROGRESSIVE SFC RIDGE OVER THE WATERS THIS MORNING WILL MOVE OFFSHORE TODAY AS A TROUGH APPROACHES FROM THE WEST. LOOKS LIKE SUB-SCA THIS AFTERNOON WITH THE STRENGTHENING SW FLOW BUT WATER/AIR TEMP DIFFERENCES SMALL. LOW PRESSURE SHOWN BY BOTH WRF AND GFS DEVELOPING WELL OFF THE VA/NC SHORE AND DEEPENING WHILE IT MOVES OFF TO THE NE. GOOD GRADIENT OVER THE WATERS SHOULD PROVIDE GOOD 25KT WINDS WITH NEAR GALE GUSTS. IF I TAKE DOWN THE SCA AT 12Z WITH AN UPDATE...I WILL PLACE THE NEW SCA FLAG FOR TONIGHT IN THE HAZARDS GRIDS. START TIME AROUND 03Z LOOKS GOOD FOR NOW. ONCE THE GRADIENT SLACKENS ON WED...WE WILL PROBABLY GO UNTIL LATER FRI WITHOUT ANY FLAGS.

HYDROLOGY... ANY PRECIPITATION THIS AFTERNOON INTO TONIGHT SHOULD BE ON THE LIGHT SIDE. THE NEXT POTENTIALLY SIGNIFICANT QPF EVENT LOOKS LIKE LATER THIS WEEKEND AND EARLY NEXT WEEK.

&&

.PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 1 AM EST THURSDAY FOR ANZ430-431-450>455.

&&

$$

UPDATE #1...OHARA UPDATE #2...NIERENBERG

.DISCUSSION FOR MORNING GRIDS/ZONES... 330 AM CST

UPPER LEVEL SPEED MAX/SHEARED OUT VORTICITY MAX FROM THE NORTHERN PLAINS INTO THE MID MISSISSIPPI RIVER VALLEY WILL CONTINUE TO SHIFT INTO THE SOUTHERN GREAT LAKES REGION TODAY. SATELLITE IMAGERY THIS MORNING INDICATING EXPANSIVE AREA OF LOW/MID CLOUD DECK ON THE CYCLONIC SHEAR SIDE OF THIS JET STREAK. SHORT TERM MODEL PROGS DO INDICATE WEAK 700-600 HPA LAYER Q-VEC CONVG WORKING ACROSS MAINLY SOUTHERN PORTIONS OF THE FORECAST AREA THROUGH MIDDAY. EXPECTING NORTHERN HALF OF CWA TO REMAIN PARTLY CLOUDY THIS MORNING...BUT MAY SEE MORE EXTENSIVE CLOUDINESS ACROSS SOUTHERN HALF OF THE FORECAST AREA THIS MORNING...BUT THEN PARTLY SUNNY CONDITIONS ARE EXPECTED ACROSS THE ENTIRE CWA BY EARLY THIS AFTERNOON. SECONDARY TROUGH AXIS CURRENTLY EXTENDS FROM SOUTHERN WISCONSIN INTO CENTRAL IOWA WITH 3-HOURLY SFC PRESSURE RISES OF 5 MB ACROSS SERN SD/SWRN MN. RATHER DEEP MIXED LAYER TO DEVELOP TODAY AS THIS REINFORCING CAA WORKS INTO THE AREA...AND MIXING DOWN OF 900 HPA MODEL THERMAL PROGS GENERALLY RESULT IN MAX TEMPS THIS AFTERNOON FAIRLY CLOSE TO INHERITED FORECAST OF LOW 30S NORTH TO MID 30S SOUTH. QUITE BREEZY TODAY ALSO WITH GUSTS UP TO 25 TO 30 MPH DEVELOPING LATE THIS MORNING AND ESPECIALLY THIS AFTERNOON.

LARGE SCALE SUBSIDENCE TO INCREASE THIS EVENING AS TAIL OF SHEARED OUT UPPER LEVEL VORT MAX CONTINUES TO SLIDE EAST OF THE AREA...AND AS BROAD UPPER LEVEL RIDGE ACROSS THE WESTERN CONUS MOVES INTO THE NORTHERN PLAINS. SKIES SHOULD CLEAR THIS EVENING...WITH POSSIBLY SOME INCREASE IN MID/HIGH LEVEL CLOUDS TOWARD WED MORNING WITH MORE PRONOUNCED MID LEVEL WAA TRACKING INTO THE AREA IN ASSOCIATION WITH THE MID LEVEL RIDGE. TEMP FORECAST FOR WEDNESDAY SHAPING UP RATHER TRICKY RIGHT NOW GIVEN SURFACE RIDGE AXIS DEPARTING AND STRONGEST LOW LEVEL SOUTHERLIES NOT WORKING INTO NORTHERN ILLINOIS UNTIL LATE AFTERNOON. MIXING SHOULD BE RATHER POOR ON WEDNESDAY SO DID NUDGE TEMPS DOWN A FEW DEGREES WITH HIGHS GENERALLY FROM MID 30S NORTH TO AROUND 40 FAR SOUTH.

MODELS BEGIN TO DIVERGE BIT IN THE WEDNESDAY NIGHT THROUGH FRIDAY IN DEALING WITH EVOLUTION OF A NORTHERN STREAM TROUGH WORKING ACROSS SOUTHERN CANADA AND ASSOCIATED COLD FRONTAL PASSAGE TIMING. NAM/WRF IS QUITE A BIT SLOWER WITH THE PROGRESSION OF THIS FEATURE THAN THE GFS WHICH SEEMS TO HAVE SUPPORT FROM A MAJORITY OF THE OTHER MODELS AND HPC PREFERENCE. MAIN IMPACT OF THIS DIFFERENCE ON THIS FORECAST IS ON COLD FRONTAL TIMING THURSDAY NIGHT INTO FRIDAY...BUT BY THIS TIME WRF/GFS ACTUALLY BEGIN TO A CONVERGE WITH THIS TIMING AS FRONTAL PROGRESSION SLOWS WITH MAIN NORTHERN STREAM WAVE MOVING ACROSS EASTERN CANADA. THURSDAY SHOULD BE WINDY IN ADVANCE OF THIS FRONT WITH A TIGHT LOW LEVEL HEIGHT GRADIENT...AND THIS LOOKS TO BE THE WARMEST DAY OF THE FORECAST WITH TEMPS GENERALLY IN THE MID TO UPPER 40S. IT STILL APPEARS SFC FRONT SHOULD STALL OUT FRIDAY NIGHT JUST SOUTH OF THE FORECAST AREA WITH SOUTHERN STREAM UPPER TROUGH THEN BECOMING THE MAIN FEATURE OF INTEREST. MAINTAINED PROLONGED PERIOD OF HIGH CHANCE POPS FROM THUR-SUN OF RA/SN WITH A SERIES OF SHORT WAVES INTERACTING WITH THIS BAROCLINIC ZONE. THERMAL PROFILES DO SUGGEST PERIODIC POTENTIAL OF SLEET/FRZ RAIN THROUGH THIS PERIOD BEGINNING MAINLY BY FRIDAY NIGHT...BUT STILL VERY DIFFICULT TO GET TOO DETAILED IN THIS REGARD YET.

MARSILI

&&

.AVIATION...

531 AM CST

S/WV DIGGING THROUGH SRN IL EARLY THIS MRNG...ASSOCIATED WITH STRONG JET STRK...125 KTS AT 500 HPA PER PROFILERS OVR MO. SHEARED VORT CHANNEL XTNDS NORTHWEST ACROSS IA BEHIND THIS SYSTEM...AND WRF/GFS BRING THIS SHEARED VORT TAIL ACROSS FCST AREA THRU MRNG HOURS TODAY. FCST SNDGS AND TSECTS INDICATE MAIN MOISTURE ABOVE 700 HPA...AND 935Z ACARS SOUNDING FROM KRFD WITH DEWPOINT TRACE DISPLAYS THIS WELL. THEREFORE...AM EXPECTING VFR CONDITIONS TO PREVAIL ACROSS TERMINAL SITES WITH CLOUDS GENERALLY AT OR ABOVE 12 KFT. SNDGS DO INDICATE PERIOD OF VFR STRATOCU POSSIBLE THIS AFTN AS LLVL CAA REALLY KICKS IN...THOUGH LCLS AROUND 4 KFT. ONCE MID LEVEL TROF AXIS PASSES THIS AFTN...DEEP SUBSIDENCE AND DRY LLVLS ERODE STRATOCU DECK...THUS XPCT JUST SOME THIN CI ALONG ANTICYCLONIC SIDE OF UPPER JET OVRNGT.

MAIN FCST FOCUS REALLY THEN IS WINDS. RELATIVELY TIGHT SFC PRESSURE GRADIENT ACROSS WRN LAKES/MS VLY...WITH 5 MB/3 HR PRES RISE MAXIMA ACROSS SRN MN/NRN IA AT 11Z INDICATIVE OF SECONDARY SFC TROF. NW WINDS 310-320 DEG ALREADY GUSTING INTO MID/UPR 20 KT RANGE IN ISALLOBARIC GRADIENT AREA OVER NERN IA...AND ALTHOUGH THIS XPCTD TO WEAKEN A BIT NEXT SVRL HOURS NAM BUFFER SNDGS INDICATE POTENTIAL FOR MID 20 KT GUSTS ACROSS NRN IL TODAY AS WELL. GRADIENT SLOWLY RELAXES THIS EVENING ALLOWING GUSTS TO FADE...WITH SFC RIDGE AXIS APPRCHG TOWARD 12Z END OF TAF PERIOD ON WED MORNING.

RATZER

&&

.LOT WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LM...SMALL CRAFT ADV IN EFFECT WINTHROP HARBOR TO GARY THROUGH TONIGHT. SMALL CRAFT ADV IN EFFECT GARY TO MICHIGAN CITY THROUGH WEDNESDAY MORNING. GALE WARNING NORTH THIRD THIS MORNING. &&

$$

.SHORT TERM... HV TWEAKED THE ONSET OF THE CLDS IN THE ERN PART OF THE CWA BACK A FEW HRS..ALTHO THEY ARE STILL ON THE WAY. WORDING FOR DC/BALT IS "CHC OF RA/SN LATE" NO ACCUM IS ANTICIPATED...ALTHO FLAKES DURG EVE DRIVE COULD ALWAYS BE PROBLEMATIC.

LOOKED AT DOLLY SODS WX CAM...SNSH OCCURRING...BUT LGT. XPCTG THESE TO INCRS DURG AFTN AFTR CD FROPA. SNOW ADVSRY RMNS IN EFFECT.

WOODY! &&

.PREV DISCUSSION... /ISSUED 410 AM EST TUE JAN 9 2006/

SHORT TERM (TONIGHT THROUGH TUESDAY)... WATER VAPOR LOOP SHOWS A LONG WAVE TROUGH ACROSS THE NORTH CENTRAL CONUS...WITH EMBEDDED WAVES MOVING EAST ACROSS THE TENNESSEE VALLEY AND SOUTHEAST ACROSS THE MIDWEST. ACARS 400-250MB WIND OBSERVATIONS REVEAL 140-180KT WINDS ROUND THE AFOREMENTIONED TROUGH.

A CLEAR START TO THE DAY WILL QUICKLY DETERIORATE WITH THE APPROACH OF A STRONG SHORTWAVE. THE VERTICAL MOTION COUPLET OF THE WAVE ACROSS SOUTHERN ILLINOIS HAS BEEN INCREASINGLY MORE IMPRESSIVE THROUGH THE NIGHT ON WATER VAPOR IMAGERY. GFS/NAM IN AGREEMENT THAT THIS WAVE FEEDING INTO THE LONGWAVE TROUGH WILL ALLOW THE TROUGH TO BECOME NEGATIVE TILTED BEGINNING LATE TODAY...CAUSING SIGNIFICANT CYCLOGENESIS OFFSHORE TONIGHT. DEEP LAYER LAPSE RATES BETWEEN 1000MB AND 500MB ARE FORECAST TO BE STEEP...NEAR 7.5C/KM. GIVEN THE SYNOPTIC SITUATION...AM CONCERNED THAT VERTICAL MOTION CAUSED BY THE SHORT WAVE LATE THIS AFTERNOON MAY BE ENOUGH TO ALLOW A 1-2 HOUR SNOW SHOWER BURST.

0C HEIGHT IS JUST OFF THE SURFACE AT 2KFT. DRY AIRMASS (PRECIPITABLE WATER VALUE OF 0.19 AT 00Z KIAD RAOB) WILL ALLOW EVAPORATIONAL COOLING. DYNAMICAL COOLING MAY BE A SIGNIFICANT FACTOR WITH IMPRESSIVE VERTICAL MOTION SHOWN BY THE NAM DURING THE LATE AFTERNOON. THIS VERTICAL MOTION IS WITHIN THE DENDRITIC SNOW GROWTH RANGE...WHICH WOULD FAVOR LARGE DENDRITE FORMATION WITHIN THE CLOUD LAYER (WITH A SHORT TRIP WITHIN THE WARM SUB-CLOUD LAYER TO THE GROUND). THERE IS ALSO INDICATION OF FRONTOGENESIS IN THE 700-850MB LAYER AS THE SYSTEM BEGINS TO DEEPEN...WHICH WOULD SUPPORT PRECIPITATION DEVELOPMENT EAST OF THE MOUNTAINS.

THERE IS LESS UNCERTAINTY ALONG THE WESTERN SLOPES OF THE MOUNTAINS WHERE TEMPERATURES ARE ALREADY SUPPORTIVE OF SNOW...AND IN FACT SNOW HAS ALREADY BEEN REPORTED AT KEKN AS OF 09Z. BEHIND THE WARM ADVECTION AND LEADING EDGE OF THE COLD ADVECTION PRECIPITATION...UPSLOPE SNOW WILL PERSIST THROUGH THE NIGHT...AS THE SKY EAST OF THE MOUNTAINS BECOMES MOSTLY CLEAR TO PARTLY CLOUDY. HAVE ISSUED A SNOW ADVISORY WITH 03Z SHORT RANGE ENSEMBLES AT KEKN INDICATING A MEAN OF 0.37" OF SNOW LIQUID EQUIVALENT THROUGH 12Z EARLY WEDNESDAY MORNING...AND A MAX OF 0.85". CURRENT SNOW FORECAST IN THE MOUNTAINS IS 1-3" TODAY AND 1-2" TONIGHT. WIND GUSTS OF 35 MPH ACROSS THE REGION TONIGHT WILL ALLOW WIND CHILLS TO NEAR ZERO ACROSS THE HIGHER TERRAIN LATE TONIGHT.

AVIATION... STRONG WAVE WILL ALLOW UPPER TROUGH TO GO NEGATIVE TILT BEGINNING LATE THIS AFTERNOON. MID LEVEL CLOUDS WILL MOVE IN DURING THE MORNING. THERE COULD BE A BRIEF SHOT OF IFR CLOUDS/VISIBILITIES WITH RAIN/SNOW SHOWERS ASSOCIATED WITH THE LEADING EDGE OF THE COLD ADVECTION. NORTHWEST DOWNSLOPE FLOW WILL DEVELOP BY EVENING AND ALLOW MUCH OF THE CLOUDS TO DISSIPATE.

MARINE... 00Z GFS/ETA MOS AT THOMAS POINT BOTH SUGGEST SUSTAINED WINDS WILL BE IN THE 10-15KT RANGE TODAY...AND 15-20KT RANGE TONIGHT. 00Z NAM PROXIMITY LAND BUFKIT FORECAST SOUNDINGS SUGGEST ADDITIONAL WIND GUST MOMENTUM OF 20 KNOTS BETWEEN 14-20Z...WHILE THE 00Z GFS INDICATES GUSTS BETWEEN 18-22 KNOTS. BOTH THE 00Z NAM AND GFS INDICATE 30KT WIND GUSTS THIS EVENING AND TONIGHT BEHIND THE COLD FRONT. SINCE THE LULL IS ONLY SEVERAL HOURS...WILL HAVE ONE SMALL CRAFT ADVISORY BEGINNING AT 14Z TODAY.

IN NW FLOW STRONG SCA WINDS ARE LIKELY TO CONTINUE ON WED. HAVE EXTENDED THE PREVIOUSLY ISSUED SCA INTO WEDNESDAY. WINDS WILL QUICKLY DIMINISH WED EVNG AS HIGH MOVES INTO THE MID ATLC.

LONG TERM...WEDNESDAY THROUGH MONDAY...

UPSLOPE SNOW SHWRS SHOULD COME TO AN END BY MIDDAY WED AS UPPER TROUGH SWINGS TO THE E AND TRAJECTORIES BECOME LESS FAVORABLE OFF THE GRT LKS. HWVR COLDEST TEMPS ALOFT PERSIST THROUGH THE DAY WED. WILL INDICATE A STRONG TOPOGRAPHICAL EFFECT ON WED WITH TEMPS IN THE HIGHER TERRAIN ONLY IN THE LOWER TO MID 20S. WED NGT THE FLOW REGIME BEGINS TO BACK TO SW...THOUGH THE WARMING TREND WILL BE VERY SLOW THROUGH THE END OF THE WEEK. SFC HIGH MOVES OFFSHORE BY FRIDAY AND WARMER TEMPS SURGE N AS A RESULT. MAX TEMPS FRI-SUN WILL WARM WELL INTO THE 50S TO AROUND 60 IN THE SE CWFA (DURING THE COLDEST TIME OF THE YR...THESE TEMPS WILL BE NEARLY 20 DEG ABOVE NORMAL).

WED NGT THROUGH FRI WILL REMAIN A DRY FCST WITH HIGH PRES SLOWLY MOVING OFF THE CST.

WARM SECTOR FOR MUCH OF THE WKEND. HAVE BACKED POPS DOWN JUST A HAIR SAT-SUN WITH THE BEST CHCS RELEGATED TO W OF THE BL RIDGE. ATTM IT REALLY DOESN`T LOOK LIKE MUCH PRECIP SHOULD REACH THE I-95 CORRIDOR TIL SUN NGT WITH THE APPROACH OF A STRONG COLD FRONT. EXCELLENT RIBBON OF LIFT IN CONJ WITH THE FRONT LATE SUN NGT AND MON...WILL INDICATE 40 POPS DURING THIS GENERAL TIMEFRAME. WILL HOLD ON TO THE COOLER TEMPS BEHIND THE FRONT MON AND ESP ON TUE.

&&

.LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...SNOW ADVISORY UNTIL 4 AM EST WEDNESDAY FOR MDZ501.

VA...SNOW ADVISORY UNTIL 4 AM EST WEDNESDAY FOR VAZ021.

WV...SNOW ADVISORY UNTIL 4 AM EST WEDNESDAY FOR WVZ054-501-503.

MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST WEDNESDAY FOR ANZ530>537.

&&

$$

.SHORT TERM...TODAY THROUGH WEDNESDAY...FORECAST CONCERNS THIS PERIOD WINDS AND LAKE EFFECT OVER FAR NORTH CENTRAL.

UPPER FEATURES OF INTEREST THIS PERIOD...CLIPPER SYSTEM MOVING SOUTHEAST THROUGH THE LAKES TODAY AND UPPER RIDGE SHIFTING EAST INTO THE PLAINS. NORTHWEST FLOW WILL GIVE WAY TO MORE OF A ZONAL PATTERN ON WED. BRIEF COOL DOWN TODAY...WITH TEMPERATURES RETURNING TO WELL ABOVE NORMAL ON WED.

TODAYS FORECAST MORE INLINE WITH CURRENT SATELLITE TRENDS WITH LESS CLOUDINESS EXPECTED. AREA OF LOW CLOUDS AND FLURRIES MOVING THROUGH NORTHERN MN ATTM AHEAD OF SHORT WAVE MOVING SOUTHEAST OUT OF THE DAKOTAS. GIVEN DRY TAMDAR SOUNDINGS FROM LAST EVENING...EXPECT TO SEE A CONTINUED DIMINISHING TREND AS IT MOVES INTO WI...THOUGH MAY ALLOW FOR SOME MOISTENING TO ENHANCE LAKE SHOWER ACTIVITY OVER LAKE SUPERIOR... WHICH AT THIS TIME HAS NOT AMOUNTED TO MUCH. LAKE INDUCED TROUGH OVER LAKE KEEPING WINDS TOO WESTERLY...WITH SAXON HARBOR OFFSHORE AT THIS TIME. OVERALL...HAVE BACKED DOWN FROM PREVIOUS FORECAST WITH WINDS NEVER BECOMING VERY FAVORABLE FOR SHOWERS TO REACH INTO VILAS COUNTY.

LOOK FOR A RATHER COLD AND BLUSTERY DAY TODAY UNDER CAA REGIME. STRONG NW GRADIENT EXPECTED THIS MORNING AS SURFACE HIGH SHIFTS EAST. PROFILERS SUPPORT GFS WINDS WITH 925MB WINDS AROUND 30 KTS THIS MORNING. HAVE STAYED AT SCA LEVELS FOR LAKE FORECASTS.

REGARDING TEMPERATURES...HAVE STAYED CLOSED TO GFS.

.LONG TERM...WED NGT THRU NXT MON. MAIN FCST CHALLENGE CONTS TO BE SNOW TRENDS THU NGT/FRI AND AGAIN SUNDAY NGT/MON BEFORE A RETURN TO TRUE WINTER TEMPS ARRIVE EARLY NXT WEEK.

THE PRES GRAD TO REMAIN TIGHT OVR THE GREAT LKS WED NGT BETWEEN THE HI PRES LOCATED OVR THE MID-ATLANTIC STATES AND LOW PRES OVR THE UPR MIDWEST. THE GFS APRS TOO FAST BRINGING THE CDFNT INTO WI CONSIDERING THE STIFF SW WNDS ALOFT AHD OF IT. PCPN CHCS APR TO REMAIN TO OUR NORTH WHERE BETTER FORCING AND LIFT TO RESIDE...WHILE DRY MID LVL ATM REMAINS OVR NE WI. DO NOT EXPECT TEMPS TO FALL VERY MUCH WED NGT DUE TO THE STRENGTH OF THE WNDS AND WAA THRU THE NGT. A SFC LOW MOVG ACROSS ONTARIO WL DRAG THE CDFNT ACROSS MOST OF WI ON THU. PBLM REMAINS DEPTH OF MSTR INVOLVED AS BETTER GULF MSTR TO ONLY BE REACHING THE MIDWEST WHILE BETTER FORCING CONTS TO PASS BY TO OUR NORTH. NOT OVERLY IMPRESSED WITH THIS WHOLE SYSTEM AND PREFER TO LWR POPS TO ONLY SLGT CATEGORY WITH MOST OF NE WI LUCKY TO SEE MORE THAN A TRACE OF PCPN. TEMPS SEEM TO WARM UP ENUF OVR E-CNTRL WI TO HAVE ANY PCPN FALL AS A RAIN/SNOW MIX AND THIS ALREADY COVERED BY PREV FCST.

AS AN UPR TROF CONTS TO DIG ACROSS THE WRN U.S. THU NGT...THE MEAN FLOW EAST OF THE CONTINENTAL DIVIDE WL BECOME MORE SW. AS THE CDFNT TRIES TO PUSH EWD...IT WL BECOME PARALLEL WITH THIS MEAN FLOW AND SLOW DOWN. THE COLDER AIR OVERSPREADING WI THU NGT IS EXPECTED TO TIGHTEN THE BAROCLINIC ZN OVR THE RGN AND WITH THE POTENTIAL OF A SFC WAVE TO MOV NE ALONG THE CDFNT...A CHC OF LGT SNOW IS PSBL ESP OVR E-CNTRL WI. NEED TO ALSO WATCH NRN WI FOR POTENTIAL LK EFFECT SNOW SHWRS AS 8H TEMPS DROP TO AROUND -15C OVR WRN LK SUPERIOR. IF TRAJS BECOME FAVORABLE...THERE WOULD BE SOME ACCUMULATING SNOW IN THE FAVORED SNOWBELT RGNS OF NRN WI. SYNOPTIC SITN OF TIGHT BAROCLINIC ZN/SFC WAVE MOVG UP THE CDFNT CARRIES OVR INTO FRI MORNING...THUS CHC POPS NEED GENERALLY ACROSS THE SE HALF OF THE FCST AREA. ACCUMULATIONS APR TO BE MINOR AT THIS POINT AS TSTMS OVR THE OHIO RIVER VALLEY INTERCEPT GULF MSTR RETURN. NORTHERLY WNDS AND COLD 8H TEMPS WOULD KEEP A CONTINUED THREAT OF LK EFFECT SNOW SHWRS FOR NRN WI THRU FRI. AS CANADIAN HI PRES PUSHES INTO THE NRN PLAINS FRI AFTERNOON...OLD CDFNT SHOULD MOV FAR ENUF EAST SUCH THAT SNOW OVR E- CNTRL WI WL BE DIMINISHING.

THE HI PRES BUILDS TOWARD THE WRN GREAT LKS FRI NGT SENDING DRIER AIR INTO WI. TRAJS WOULD TURN NE WHICH IS NOT A GOOD DIR FOR LK EFFECT OVR NRN WI...THUS CANNOT SEE MORE THAN FLURRIES FOR VILAS CNTY. AS FOR THE REST OF NE WI...NOT CONVINCED ABT SNOW CHCS DESPITE A SOMEWHAT TIGHT BAROCLINIC ZN OVR WI. WHILE SOME FLURRIES ARE PSBL...PREFER TO TRY AND FIND A DRY PERIOD DURING THIS ACTIVE PERIOD. ENUF DRY AIR ON EASTERLY WNDS SHOULD PRECLUDE ANY PCPN GOING INTO SAT EVEN THO CLDS TO BE ON THE INCREASE AS THE UPR TROF MAKES AN EWD MOV INTO THE CNTRL U.S.

STILL APRS THAT THIS UPR TROF WL MAKE A MOV TOWARD THE WRN GREAT LKS BY SUNDAY AS A 130+ KT UPR JET ROUNDS THE BASE OF THE TROF. ANTICIPATE A SFC LOW TO DVLP OVR THE SRN PLAINS SAT NGT AND RACE NE INTO THE ERN GREAT LKS ON SUNDAY. THIS TRACK WOULD GENERALLY KEEP HEAVIER PCPN TO OUR SOUTH AND EAST...BUT ACCUMULATING SNOW ON THE ORDER OF 2 TO 4 INCHES ARE PSBL BY 00Z MON ESP OVR E-CNTRL WI. PCPN TO DIMINISH SUNDAY NGT AS THE SFC LOW HEADS TOWARD THE CANADIAN MARITIMES AND INITIAL UPR TROF ROTATES EWD. MAIN STORY BY EARLY NXT WEEK TO BE THE INFLUX OF MUCH COLDER AIR INTO THE RGN. WL HAVE TO WATCH FOR ANOTHER ROUND OF LK EFFECT SNOWS FOR NRN WI AS 8H TEMPS PLUNGE TO AT LEAST -20C.

&&

.GRB WATCHES/WARNINGS/ADVISORIES... NONE &&

$$ TE/KALLAS WEATHER.GOV/GREENBAY

.SYNOPSIS... 20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED TROUGHING DIGGING DOWN THE WEST COAST OF BRITISH COLUMBIA INTO THE PACIFIC NW...RIDGING OVER SOUTHERN ALBERTA AND SASKATCHEWAN AND A LARGE TROUGH COVERING THE GREAT LAKES. WITHIN THIS LARGE TROUGH...A 510 DAM UPPER LOW WAS LOCATED HALF WAY BETWEEN LAKE SUPERIOR AND JAMES BAY. 850MB TEMPS ARE FAIRLY COLD UNDER AND IMMEDIATELY WEST OF THE UPPER LOW...AS NOTED BY THE -27C TEMP AT PICKLE LAKE ONTARIO (CWPL) AT 12Z. EVEN AWAY FROM THE UPPER LOW...INL AND MOOSONEE ONTARIO REPORTED AROUND -18C AT 12Z. WITH 45 KT NW 850MB WINDS AT BOTH INL AND CWPL...THESE COLD READINGS CONTINUE TO FLOW INTO THE CWA... RESULTING IN PLENTY OF LAKE EFFECT SNOW SHOWERS. HOWEVER...THESE SNOW SHOWERS HAVE OVERALL BEEN WEAK DUE TO A COMBINATION OF FACTORS. FIRST IS DRY AIR ADVECTION...NOTED BY BELOW ZERO F DEWPOINTS ON THE NORTH SIDE OF LAKE SUPERIOR. SECOND...INVERSION HEIGHTS AT MOST ARE AROUND 7000 FT BASED ON THE 12Z TAMDAR SOUNDING FROM SAWYER. THIRD...THE FLOW IS MAINLY UNIDIRECTIONAL...CAUSING MULTI-PARALLEL BANDS WHICH NORMALLY DO NOT PRODUCE MUCH SNOWFALL...ESPECIALLY BY THEMSELVES. ALTHOUGH THE SNOW MAY NOT BE THAT STRONG...THE WINDS HAVE BEEN. MUCH OF THE 850MB WIND OBSERVED ON THE SOUNDINGS UPSTREAM IS BEING MIXED DOWN TO THE LAKE SUPERIOR SURFACE DUE TO THE COLD ADVECTION...AND GALE FORCE WINDS OR WIND GUSTS HAVE BEEN REPORTED AT MANY SITES OVER THE EASTERN 2/3 OF LAKE SUPERIOR TODAY. AWAY FROM THE LAKE EFFECT SNOW IN THE SOUTH CENTRAL U.P....SKIES HAVE BEEN MAINLY PARTLY CLOUDY...THANKS TO THE DRY AIR ADVECTION. AS FAR AS THE SURFACE PRESSURE PATTERN GOES...A 1028MB HIGH PRESSURE RIDGE WAS CENTERED OVER WESTERN MINNESOTA WHILE 980S MB LOW PRESSURE WAS OVER NE QUEBEC.

&&

.SHORT TERM (TONIGHT AND WED)...

UPPER TROUGH OVER THE GREAT LAKES WILL CONTINUE TO MOVE TO THE EAST OVER THE NEXT 24 HOURS DUE TO THE RIDGE OVER MONTANA BEING PUSHED EASTWARD BY THE BRITISH COLUMBIA TROUGH. BY 00Z THU...THE RIDGE AXIS IS PROGGED TO BE LOCATED OVER THE CWA...ALLOWING WARMER TEMPERATURES ALOFT TO MOVE INTO THE AREA. UNTIL THEN...HOWEVER... 850MB TEMPS ARE EXPECTED TO REMAIN ON THE COLD SIDE WITH READINGS AROUND -20C THIS EVENING ONLY WARMING TO -13 TO -17C BY 12Z WED. SINCE LAKE SURFACE TEMPERATURES ARE AROUND 4C...LAKE EFFECT SNOW SHOWERS WILL CONTINUE. ONE DIFFERENCE TONIGHT FROM TODAY... THOUGH...WILL BE THE WIND DIRECTION BACKING AS THE SURFACE RIDGE OVER WESTERN MINNESOTA MOVES TO WESTERN UPPER MICHIGAN BY 12Z. THIS BACKING...COMBINED WITH PERSISTENT DRY AIR ADVECTION SHOULD KEEP AMOUNTS DOWN IN THE WESTERN U.P.. WITH THE BETTER FETCH LENGTH ON EASTERN LAKE SUPERIOR...ALLOWING FOR A LITTLE MOISTENING...HAVE KEPT 2 TO 4 INCH AMOUNTS GOING TONIGHT IN THE UPSLOPE AREAS OF THE EASTERN U.P.. AS THE SURFACE RIDGE CONTINUES MOVING ACROSS ON WED DUE TO THE UPPER RIDGE BEING PUSHED EASTWARD...THE LAKE EFFECT SNOW IS EXPECTED TO END FOR THE NORTHERN U.P.. HOWEVER...THE SOUTHERLY WIND DEVELOPING ON THE BACK SIDE OF THE HIGH IS EXPECTED TO RESULT IN DECENT DEEP ISENTROPIC LIFTING ACROSS THE CWA...AS SHOWN BY THE NAM AND GFS. ALTHOUGH SOME DRY AIR EXISTS IN THE 750-900MB LAYER... THE VERTICAL MOTION DUE TO THE WARM ADVECTION MAY BE ENOUGH TO PRODUCE SOME LIGHT SNOW...ESPECIALLY OVER THE NW PORTION OF THE CWA IN THE AFTERNOON WHERE BETTER MOISTURE IS PRESENT. THEREFORE HAVE RAISED POPS. ALSO HAVE HIGHER POPS IN SOUTHERN SCHOOLCRAFT COUNTY WHERE SOUTHERLY WINDS AND COOL TEMPS AT 850MB (RISING TO -7C BY 00Z THU OVER NORTHERN LAKE MICHIGAN) MAY BRING LAKE EFFECT SNOW THERE.

BLUSTERY CONDITIONS OBSERVED TODAY WILL BEGIN TO DECREASE TONIGHT... AND ESPECIALLY BY WED MORNING AS THE RIDGE MOVES IN. THE DECREASE... ALONG WITH SOME CLEARING IN THE SOUTHWESTERN U.P. MAY ALLOW TEMPS TO FALL TO NEAR ZERO TONIGHT...ESPECIALLY GIVEN THE DRY ATMOSPHERE. AS THE RIDGE CROSSES THE CWA ON WED...SOUTHERLY WINDS PICKING BACK UP WILL HELP TO WARM THE TEMPERATURES...BOTH ALOFT AND AT THE SURFACE...ESPECIALLY IN DOWNSLOPE AREAS. HOWEVER...THE WIND WILL MAKE IT FEEL COOLER SINCE READINGS ARE ONLY EXPECTED IN THE 20S TO AT MOST 30F PER MET/MAV GUIDANCE.

.LONG TERM (WED NIGHT THROUGH TUE)...

WED NIGHT/THU...SHORTWAVE WILL TRACK FROM SRN SASKATCHEWAN/MANITOBA WED EVENING TO ONTARIO THU AFTN WITH ASSOCIATED SFC LOW PASSING JUST N OF LAKE SUPERIOR. STRONG ISENTROPIC ASCENT WILL BE THE RULE WED NIGHT...BUT WITH FOCUS OF STRONGEST ASCENT/DEEP LAYER MOISTENING GENERALLY ACROSS N HALF OF LAKE SUPERIOR INTO ONTARIO. CANADIAN/GFS/UKMET RUNS HAVE BEEN VERY CONSISTENT ON THIS. MIXING RATIOS OF 2-3G/KG ON 290K SFC (ROUGHLY 700-750MB) SUPPORT GENERAL 3-5 INCH SNOW ACCUMULATIONS IN AXIS OF BEST LIFT/MOISTENING WHICH WILL BE JUST N OF HERE...BUT SRN FRINGE OF SNOW SHOULD IMPACT NRN AND ERN UPPER MI. HAVE PAINTED 1 TO MAYBE 2 INCH ACCUMULATIONS ON THE KEWEENAW. SIMILAR AMOUNTS ARE POSSIBLE OVER THE E WHERE THERE MIGHT ALSO BE A BRIEF WINDOW FOR LAKE ENHANCEMENT IN SSW FLOW OFF LAKE MICHIGAN. TEMPS WED NIGHT WILL LIKELY REMAIN STEADY OR SLOWLY RISE FROM EARLY EVENING READINGS DUE TO BLUSTERY S WINDS/WAA AND CLOUD COVER. 850MB WINDS OF 50 KTS AND 8MB/6HR PRES FALL MAX PASSING JUST N OF LAKE SUPERIOR WILL WORK TO KEEP SFC WINDS GUSTY. SHOULD ESPECIALLY BE GUSTY OVER THE ERN FCST AREA WHICH IS FAVORED IN S WIND SITUATIONS (LOCATIONS SUCH AS KISQ/KERY/GRAND MARAIS AND MARQUETTE).

PERSISTENT...BUT WEAKER ISENTROPIC ASCENT WILL CONTINUE THU SO ANY LINGERING -SN SHOULD DIMINISH OR EVEN END. SHORTWAVE/SFC LOW ARE WEAKER THAN PREVIOUS MODEL RUNS...SO COLDER AIR WILL BE SLOWER TO SLIP BACK INTO THE AREA. IN FACT...IT MAY NOT BE UNTIL LATE THU NIGHT THAT AIRMASS BECOMES COLD ENOUGH TO GET LES GOING AGAIN OFF LAKE SUPERIOR.

THU NIGHT/FRI...COMBINATION OF RIGHT ENTRANCE OF JET STREAK RUNNING FROM JUST N OF LAKE SUPERIOR TO QUEBEC AND A WEAK SHORTWAVE LIFTING INTO THE GREAT LAKES SHOULD RESULT IN SOME LIGHT SNOW SPREADING N OF THE COLD FRONT THAT WILL PASS THRU UPPER MI THU AFTN/EVENING. HAVE INCLUDED MID RANGE CHC POPS LATE THU NIGHT/FRI MORNING OVER THE SE FCST AREA. MEANWHILE...LES SHOULD PICK UP A BIT OFF LAKE SUPERIOR FRI AS LAKE-850MB DELTA-T INCREASES TO 13-18C WITH DECENT MOISTURE PROFILE FOR A TIME.

SAT THRU TUE...WILL BE A COLD PERIOD THAT COULD POTENTIALLY TURN QUITE COLD. OTHER THAN THE COLD...MAIN FCST CHALLENGE IS THE POSSIBILITY OF A WIDESPREAD SYNOPTIC SNOW OVER THE FCST AREA DURING THE WEEKEND. 00Z/12Z RUNS IN GENERAL HAVE TRENDED TOWARD A BETTER POTENTIAL FOR SNOW COMPARED TO YESTERDAY AS THERE ARE A FEW MODEL RUNS INDICATING A SIGNIFICANT SNOW EVENT NOW. ON SAT...ATTENTION WILL BE ON ENERGY OVER THE SW CONUS. AS SYSTEM LIFTS NE...ONE COMPLICATION IS THE DEGREE OF INTERACTION WITH SHORTWAVE ENERGY DROPPING S THRU CNTRL CANADA. 00Z UKMET HAS A LITTLE MORE INTERACTION THAN THE OTHER MODELS AND ACTUALLY BRINGS A STRONG NEGATIVE TILT SHORTWAVE INTO THE UPPER LAKES SUN WITH ASSOCIATED 984MB SFC LOW INTO NCNTRL WI BY 00Z MON. WOULD END UP BEING A MIXED PCPN EVENT FOR A GOOD PART OF FCST AREA WITH HVY SNOW OVER THE FAR W. GULF MOISTURE INFLOW WOULD BE EXCELLENT TO PROVIDE HVY PCPN. THIS IS A HUGE CHANGE FROM PREVIOUS UKMET RUNS WHICH EITHER HELD ENERGY BACK OVER THE SW OR BROUGHT A WEAK WAVE INTO THE OHIO VALLEY. 12Z UKMET TRENDED WEAKER...BUT STILL HAS A DECENT SFC LOW TRACKING THRU NRN LWR MI WHICH WOULD PROVIDE WIDESPREAD SIGNIFICANT SNOW TO FCST AREA SUN. ECMWF HAS TRENDED STRONGER WITH SHORTWAVE AND FARTHER N WITH SFC LOW (SRN PLAINS TO NW IL ACROSS NRN LWR MI)...BUT IT MAINTAINS THE OVERALL POSITIVE TILT TROF ORIENTATION THAT HAS BEEN THE CONSENSUS SOLUTION IN RECENT DAYS. STILL...00Z RUN OFFERS A QUICK HITTING MDT/HVY SNOW EVENT FOR FCST AREA SAT NIGHT/SUN... ESPECIALLY NW 2/3RDS. 12Z ECMWF IS NEARLY IDENTICAL TO 00Z. 00Z/06Z GFS SOLUTIONS ARE SIMILAR TO THE BULK OF ITS RUNS THE LAST FEW DAYS...WHICH IS TO BRING SFC LOW THRU SE LWR MI. THIS WOULD BRING NRN EDGE OF SYNOPTIC SNOW INTO FCST AREA WITH LAKE ENHANCEMENT UNDER N OR NE WINDS. GFS ENSEMBLES SHOW ONE MEMBER WITH SFC LOW TRACKING INTO ERN UPPER MI...BUT REMAINDER OF MEMBERS ARE CLUSTRED CLOSE TO 00Z/06Z OPERATIONAL GFS TRACK WITH ONLY TIMING ISSUES. 12Z GFS HAS SHIFTED LOW TRACK S A BIT. 00Z CANADIAN WAS MOST SUPPRESSED WITH SFC LOW TRACK...BUT 12Z RUN NOW BRINGS A 995MB SFC LOW INTO SRN LWR MI MON. OVERALL...MODEL RUNS SINCE 12Z/8JAN SUGGEST A BETTER POTENTIAL OF GETTING SYNOPTIC SNOW INTO UPPER MI...SO WILL INCLUDE CHC POPS ALL AREAS LATE SAT NIGHT/SUN. SYSTEM WILL OBVIOUSLY BE SOMETHING TO WATCH OVER THE COMING DAYS AS THERE IS POTENTIAL FOR A SIGNIFICANT SNOW. WILL MAKE A MENTION OF THIS POSSIBILITY IN HAZARDOUS WEATHER OUTLOOK. IN THE WAKE OF THE SYSTEM...COLDER AIR WILL DUMP INTO THE UPPER LAKES. 00Z GFS BROUGHT BACK THE IDEA OF 850MB TEMPS HEADING TOWARD -30C LATE MON...BUT THAT IS STILL AN OUTLIER SOLUTION. WILL MORE LIKELY SEE 850MB TEMPS OF -20 TO -25C...SO BLO NORMAL TEMPS SHOULD BE THE RULE EARLY NEXT WEEK. OF COURSE...LES WILL CONTINUE NEAR LAKE SUPERIOR.

&&

.MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW AND BLSN ADVY UNTIL 4 AM WED MIZ006-007-085. GALE WARNING LAKE SUPERIOR AND LSZ245>248. &&

$$

AJ (SHORT TERM) ROLFSON (LONG TERM)

.SYNOPSIS... 16Z WATER VAPOR LOOP AND 12Z RAOBS SHOWED UPPER TROUGHING COVERING ALL OF THE GREAT LAKES WHILE RIDGING EXTENDING FROM THE NORTHERN ROCKIES INTO ALBERTA AND SASKATCHEWAN. WITHIN THIS TROUGH...A 510 DAM UPPER LOW CAN BE SEEN MOVING ACROSS NORTHEAST ONTARIO. 850MB TEMPS ARE FAIRLY COLD UNDER AND IMMEDIATELY WEST OF THE UPPER LOW...AS NOTED BY THE -27C TEMP AT PICKLE LAKE ONTARIO (CWPL). EVEN AWAY FROM THE UPPER LOW...INL AND MOOSONEE ONTARIO REPORTED AROUND -18C. WITH 45 KT NW 850MB WINDS AT BOTH INL AND CWPL...THESE COLD READINGS CONTINUE TO FLOW INTO THE CWA...RESULTING IN PLENTY OF LAKE EFFECT SNOW SHOWERS. HOWEVER...THESE SNOW SHOWERS HAVE OVERALL BEEN WEAK DUE TO A COMBINATION OF FACTORS. FIRST IS DRY AIR ADVECTION... NOTED BY BELOW ZERO F DEWPOINTS ON THE NORTH SIDE OF LAKE SUPERIOR. SECOND...INVERSION HEIGHTS AT MOST ARE AROUND 7000 FT BASED ON THE 12Z TAMDAR SOUNDING FROM SAWYER. THIRD...THE FLOW IS MAINLY UNIDIRECTIONAL...CAUSING MULTI-PARALLEL BANDS WHICH NORMALLY DO NOT PRODUCE MUCH SNOWFALL...ESPECIALLY BY THEMSELVES. ALTHOUGH THE SNOW MAY NOT BE THAT STRONG...THE WINDS HAVE BEEN. MUCH OF THE WIND SPEED OBSERVED ON THE SOUNDINGS UPSTREAM IS BEING MIXED DOWN TO THE LAKE SUPERIOR SURFACE DUE TO THE COLD ADVECTION...AND GALE FORCE WINDS OR WIND GUSTS HAVE BEEN REPORTED AT MANY SITES OVER THE EASTERN 2/3 OF THE LAKE. AWAY FROM THE LAKE EFFECT SNOW IN THE SOUTH CENTRAL U.P....SKIES HAVE BEEN MAINLY PARTLY CLOUDY...THANKS TO THE DRY AIR ADVECTION. AS FAR AS THE SURFACE PRESSURE PATTERN GOES...A 1028MB HIGH PRESSURE RIDGE WAS CENTERED OVER THE PLAINS WHILE 980S MB LOW PRESSURE WAS OVER NE QUEBEC.

&&

.UPDATE...

THE UPPER RIDGE OVER THE NORTHERN ROCKIES WILL BE PUSHED EASTWARD TO THE PLAINS BY THIS EVENING BY A TROUGH DIGGING DOWN THE WEST COAST OF BRITISH COLUMBIA. THIS RIDGE IS PROGGED TO PUSH THE UPPER TROUGH OVER THE GREAT LAKES...AND THE UPPER LOW OVER NE ONTARIO...EASTWARD. THEREFORE UPPER MICHIGAN WILL NOT SEE THE COLD 850MB TEMPS OBSERVED AT PICKLE LAKE...BUT READINGS AROUND -20C ARE EXPECTED OVER LAKE SUPERIOR BY 22Z. THEREFORE MULTI-PARALLEL BAND LAKE EFFECT SNOW SHOWERS WILL PERSIST. INVERSION HEIGHTS SHOULD RISE AS THE COLD AIR ADVECTS IN...WHICH MAY CAUSE THE LAKE EFFECT TO INTENSIFY. HOWEVER...SINCE THE COLD AIR IS ALSO BRINGING IN DRIER DEWPOINTS... THE EFFECT OF THE INVERSION HEIGHT INCREASE MAY BE NEGATED. IN ADDITION...WITH COLDER AND DRIER AIR MOVING IN OVER THE RELATIVELY WARM WATER...CLOUD BASES MAY RISE ABOVE THE SNOW GROWTH LAYER...OR THE SNOW GROWTH LAYER WILL BECOME VERY SMALL. ANOTHER PROBLEM THAT HAS BEEN OCCURRING FOR SNOWFALL AMOUNTS THIS MORNING IS THE STRONG WINDS WHICH ARE BOTH BREAKING PART THE SNOWFLAKES AND NOT ALLOWING SNOW TO STAY IN ONE SPOT AND ACCUMULATE. FOR NOW HAVE DECIDED TO CONTINUE THE GOING FORECAST...WITH AMOUNTS NEAR THE MINIMUM FOR ADVISORY CRITERIA IN THE EASTERN U.P.. LESSER AMOUNTS ARE FORECAST IN THE WESTERN U.P. DUE TO THE SHORTER FETCH FOR NW WINDS ACROSS WESTERN LAKE SUPERIOR.

SINCE THE PRESSURE GRADIENT IS EXPECTED TO REMAIN TIGHT THROUGH THIS AFTERNOON AND COLD AIR ADVECTION IS OCCURRING...WINDS SHOULD REMAIN BLUSTERY OR EVEN INTENSIFY A BIT. BASED ON OBSERVATIONS FROM GRANITE ISLAND AND GRAND MARAIS...HAVE EXPANDED THE GALE WARNING TO INCLUDE A FEW MORE LAKE SUPERIOR NEARSHORE ZONES AND ALSO CHANGE OUR LAKE EFFECT SNOW ADVISORY TO A LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY.

AS FAR AS TEMPERATURES GO...NOT MUCH RISE IS EXPECTED GIVEN THE COLD AIR ADVECTION. THEREFORE HAVE LOWERED HIGHS A FEW DEGREES FROM THE PREVIOUS FORECAST.

ZFP...WSW AND GRID UPDATES ALREADY OUT.

&&

.PREV DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE SNOWFALL POTENTIAL FOR TODAY AND TONIGHT.

WATER VAPOR IMAGERY AND RUC DEPICT A LONGWAVE TROUGH OVER EASTERN CANADA AND A BROAD RIDGE OVER THE NORTHERN ROCKIES. WEAK SHORTWAVE SLIDING DOWN THE LEE OF THE ROCKIES RIDGE IS OVER SOUTHERN U.P. A DEEPER SHORTWAVE IS OVER THE EASTERN DAKOTAS STRETCHING INTO MISSOURI. THIS IS FOLLOWED BY ANOTHER SHORTWAVE OVER SOUTHERN SASKATCHEWAN. SURFACE ANALYSIS DEPICTS A RIDGE OVER WESTERN DAKOTAS RUNNING NORTH THROUGH SASKATCHEWAN AND A DEEP LOW OVER EASTERN QUEBEC. A SURFACE LOW IS MOVING ASHORE OVER SOUTHERN BRITISH COLUMBIA...WITH A WARM FRONT STRETCHING SOUTH FROM IT THROUGH CENTRAL MONTANA. STRONG WINDS AND LIGHT SNOW IS ACCOMPANYING THE SHORTWAVE OVER THE DAKOTAS OTHERWISE LITTLE PRECIPITATION IS OCCURRING. 850MB TEMPERATURE ANALYSIS SHOW A POCKET OF COLD AIR OVER WESTERN ONTARIO...WHERE THE TEMPERATURES DROP TO -24C. THIS IS PRODUCING A DELTA-T OVER NORTHERN LAKE SUPERIOR OF AROUND 21C. SOUNDINGS CONTINUE TO SHOW DRY BELOW 900MB. THE LOWEST INVERSION IS AROUND 3K FEET WHICH APPEARS TO BE HAMPERING LES SNOW GROWTH.

A WEAK MID LEVEL LOW ROTATING THROUGH THE BASE OF THE LONGWAVE TROUGH WILL MOVE FROM NORTHEAST MANITOBA THROUGH NORTHERN ONTARIO INTO SOUTHERN JAMES BAY TODAY. A WEAK SHORTWAVE ROTATING AROUND THE JAMES BAY LOW WILL SWEEP THROUGH EASTERN LAKE SUPERIOR INTO EASTERN U.P...WHILE THE DAKOTA SHORTWAVE SLIDES INTO EXTREME WESTERN LAKE SUPERIOR AND EASTERN WISCONSIN. THE SURFACE RIDGE WILL SLIDE INTO MINNESOTA AND WESTERN ONTARIO. A SURFACE LOW WILL BE OVER SOUTHERN BRITISH COLUMBIA MOVING INTO WESTERN ALBERTA. THE COLD POOL OF AIR WILL SLIP INTO EAST CENTRAL ONTARIO AND SPILL OVER INTO EASTERN LAKE SUPERIOR CAUSING A LAKE-850MB DELTA-T OF 24C. THE INVERSION WILL LIFT TODAY REACHING 5K FEET OVER WESTERN LAKE SUPERIOR AND TO AROUND 7K FEET OVER EAST. SOUNDING FORECAST DEPICTS A SATURATED LAYER BETWEEN 900MB AND 850MB OVER MOST OF THE FORECAST AREA. CONDITIONS ARE EXPECTED TO BE A LITTLE DRIER BELOW 900MB. SURFACE TEMPERATURES REMAIN IN THE SINGLE DIGITS OVER WESTERN ONTARIO...AND -4C TO -9C OVER NORTHERN MANITOBA. TRAJECTORY PROGS INDICATE THAT THE ONTARIO AIR MASS WILL SLIDE OVER THE FORECAST AREA. THUS...THE INSTABILITY WILL LIKELY PRODUCE SNOW AND SNOW SHOWERS...HOWEVER... THE AMOUNT OF SNOWFALL SHOULD BE FAIRLY LIMITED. SURFACE WINDS WILL REMAIN STRONG (25 TO 35 KTS) OVER LAKE SUPERIOR. THIS WILL ALSO SHORTEN THE EFFECTIVE FETCH ACROSS THE LAKE. THUS EXPECT SNOWFALL AMOUNTS TO BE ON THE ORDER TO 2 TO 4 INCHES ACROSS THE KEWEENAW PENINSULA AND OVER THE SNOW PRONE AREAS OF EASTERN U.P.

MODELS CONTINUE TO BE IN VERY GOOD AGREEMENT. THE ONTARIO SHORTWAVE WILL SWING INTO SOUTHWEST QUEBEC DRAWING THE WEAK SHORTWAVE QUICKLY ACROSS THE FORECAST AREA TONIGHT. Q-VECTORS SUGGEST MOSTLY DIVERGENCE ACROSS THE AREA BY LATE TONIGHT. THE MID LEVEL RIDGE WILL SHIFT INTO MANITOBA. THE SOUNDING FORECAST SHOW THE INVERSION WILL LOWER OVERNIGHT TO 2.5K FEET OVER THE WEST TO 4.5K FEET OVER THE EAST. WHERE LES SHOULD CONTINUE. MEANWHILE...THE SURFACE RIDGE WILL MOVE OVER THE FORECAST AREA WEAKENING THE GRADIENT WINDS. THUS THE WINDS SHOULD DIE DOWN INCREASING THE FETCH LENGTH OVER THE EASTERN PART OF THE LAKE. THIS SEEMS TO FAVOR A BETTER POTENTIAL SNOWFALL OVER THE EASTERN COUNTIES.

THE MID LEVEL RIDGE WILL SLIDE OVER THE UPPER GREAT LAKES WHILE A MID LEVEL LOW MOVES INTO SOUTHWEST MANITOBA ON WEDNESDAY. THE SURFACE LOW WILL ALSO MOVE INTO SOUTHWEST MANITOBA DRAGGING A COLD FRONT INTO THE DAKOTAS. THE SURFACE RIDGE WOULD DEVELOP OVER EASTERN U.S. SLOWING THE PROGRESSION OF THE MANITOBA LOW AND MAY EVEN DIVERT IT A LITTLE NORTHEAST. 850MB THERMAL TROUGH WILL BEGIN TO MOVE EAST. THE DELTA-T`S WILL LOWER TO AROUND 15C AS WARM AIR ADVECTS IN FROM THE SOUTHWEST IN THE FLOW AROUND THE LOW OVER MANITOBA. 290K ISENTROPIC ANALYSIS SUGGEST FAIRLY SIGNIFICANT LOW LEVEL ASCENT ACROSS THE FORECAST AREA AHEAD OF THE NEXT SYSTEM. DEEP MOISTURE IS DEPICTED TO PASS OVER NORTHERN ONTARIO. THE AVAILABLE MOISTURE... ISENTROPIC ASCENT AND LOW LEVEL ADIABATIC LIFT ASSOCIATED WITH THE COOL 850MB TEMPERATURES APPEARS TO GIVE A CHANCE OF DEVELOPING SOME SNOW ACROSS THE AREA. THE LACK OF INSTABILITY IN THE MID LEVELS... AND THE SHORT TIME PERIOD OF DEEP MOISTURE SWEEPING THROUGH THE AREA WILL SET THE PACE FOR THE AMOUNT OF LAKE EFFECT SNOWS.

THE MID LEVEL SHORTWAVE OVER WISCONSIN WILL RACE ACROSS THE FORECAST AREA WEDNESDAY NIGHT. THE SURFACE LOW WILL SPEED INTO THE CWQT AREA DRAGGING A COLD FRONT INTO WESTERN U.P. MODELS SUPPORT HAVE SIGNIFICANT AMOUNT OF LOW LEVEL MOISTURE OVER THE FORECAST AREA. ISENTROPIC ASCENT AHEAD OF THE FRONTAL BOUNDARY WILL ADD THE LIFT TO DEVELOP SNOWS ACROSS THE AREA.

THE SHORTWAVE WILL SAIL ACROSS CENTRAL ONTARIO...AND REMAIN NORTH OF THE FORECAST AREA ON THURSDAY. A COLD FRONT WILL SWEEP THROUGH THE FORECAST AREA. DELTA-T`S OVER LAKE SUPERIOR WILL BE AROUND 16C. COLD AIR WILL BE ADVECTING INTO THE AREA WITH AN 850MB THERMAL TROUGH OF AROUND -22C MOVING INTO MANITOBA AND NORTH DAKOTA. LAKE EFFECT SNOW STILL SHOULD HANG IN THERE. DRY AIR MOVING INTO THE AREA WILL BE THE LIMITING FACTOR AGAIN. THERE WILL BE ONLY A NARROW LAYER OF MOISTURE BETWEEN 850MB AND 900MB. ANY SNOW FALL SHOULD BE LIGHT.

A WEAK SHORTWAVE WILL SWEEP INTO THE SOUTHERN PART OF THE FORECAST AREA ON THURSDAY NIGHT...OTHERWISE...THE SHORTWAVES WILL STAY IN THE FLOW OVER CENTRAL ONTARIO. THE COLD FRONT WILL EXIT THE EASTERN U.P. ALLOWING COLD AIR TO ADVECT INTO THE REGION. A POOL OF COLD AIR WILL SETTLE OVER SOUTHERN MANITOBA AND WESTERN ONTARIO. A DELTA-T OF 22C WILL OCCUR OVER ALONG THE NORTHWEST SHORE OF LAKE SUPERIOR. A LARGE DOME OF HIGH PRESSURE WILL EXPAND OVER THE NORTHERN PLAINS AND SOUTH CENTRAL CANADA. THE ANTI-CYCLONIC FLOW WILL PRODUCE A NORTH WIND ACROSS THE AREA. THIS WILL PRODUCE SOME LAKE EFFECT SNOW SHOWERS ACROSS THE NORTHERN U.P. THE DRY AIR BEHIND THE FRONT WILL LIMIT THE AMOUNT OF SNOWFALL.

&&

.MQT WATCHES/WARNINGS/ADVISORIES... LAKE EFFECT SNOW AND BLOWING SNOW ADVISORY UNTIL 4 AM WED MIZ006-007-085. GALE WARNING LAKE SUPERIOR AND LSZ245>248. &&

$$

AJ (UPDATE) DLG (PREV DISCUSSION)