Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 01/31/07

.SHORT TERM /TONIGHT THROUGH TUESDAY/...

WATER VAPOR LOOP SHOWS A TROUGH MOVING INTO THE ATLANTIC...AS THE NEXT UPPER LOW DROPS SOUTH INTO THE UPPER MIDWEST. ACARS 400-250MB WIND OBSERVATIONS REVEAL A NORTHWESTERLY 120-160KT JET FROM THE PLAINS THROUGH THE SOUTHEAST CONUS. 11Z SURFACE ANALYSIS PLACED THE ARCTIC BOUNDARY FROM A 1000MB OCCLUDED CYCLONE IN NORTHERN MINNESOTA EAST THROUGH THE UPPER GREAT LAKES AND NEW ENGLAND. A 1028MB ANTICYCLONE DOMINATED THE GULF STATES. A TROUGH WAS LOCATED IN LEE OF THE APPALACHIANS.

WARM ADVECTION WILL BE INCREASING WITHIN THE MID LEVELS OVERNIGHT AS THE NEXT WAVE ROTATES EAST FROM THE UPPER MIDWEST. THIS WILL BRING PERIODS OF MID LEVEL CLOUDS OVERNIGHT ON NEARLY ZONAL FLOW ALOFT. THERE WILL BE SEVERAL HOURS OF CLEAR SKY DURING THE EVENING...ALLOWING TEMPERATURES TO FALL EFFICIENTLY WITH DECOUPLING IN THE DRY AIRMASS. EXPECT TEMPERATURES TO RISE IN THE HIGHER TERRAIN AS SOUTHWEST WINDS BRING IN WARMER AIRMASS ALOFT OVERNIGHT.

THE NEXT WAVE WILL BE SHEARING INTO THE REGION THROUGH THE DAY TUESDAY. THIS WILL ALLOW CLOUDS TO THICKEN ACROSS THE REGION...AND THEREFORE WENT A FEW DEGREES BELOW MOS GUIDANCE FOR HIGH TEMPERATURES. EXPECT WESTERLY FLOW TO INDUCE SOME UPSLOPE PRECIPITATION ACROSS THE MOUNTAINS BY THE END OF THE DAY. 12Z NAM/GFS BUFKIT FORECAST SOUNDINGS INDICATE STEEPENING MID LEVEL LAPSE RATES WITHIN THE CLOUD LAYER...AND HAVE INTRODUCED LOW CHANCE OF SNOW SHOWERS AS FAR SOUTH AS WASHINGTON DC...AND FLURRIES INTO CENTRAL VIRGINIA DURING THE LATE AFTERNOON.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...

12Z GFS MODEL COMING MORE IN LINE WITH EUROPEAN MODEL IN RESPECT TO TIMING AND TRACK OF COASTAL LOW EXPECTED TO IMPACT THE AREA ON THU-THU NIGHT. LATEST ENSEMBLE PLOT ALSO SHOWS GOOD CLUSTERING WITH THIS LOW INCREASING CONFIDENCE ON A WINTER PRECIP EVENT ACROSS THE AREA THU-THU NIGHT. THIS IS ABOUT 24 HRS FASTER THAN RUNS FROM 24 HRS AGO. TREND IN THE MODELS IS ALSO FOR A FURTHER EAST TRACK AND TO HOLD THE COLD AIR AT THE SFC LONGER RESULTING IN A MOSTLY FROZEN PRECIP EVENT. WILL CONTINUE TO USE GENERIC RAIN/SNOW WORDING AS THIS EVENT IS STILL MORE THAN 72 HRS AWAY AND THERE IS STILL PRECIP TYPE ISSUES. LOW IS WELL OFFSHORE BY 12Z FRI.

REST OF THE EXTENDED...CONTINUED COLD PATTERN AND MAINLY DRY AS SVRL SURGES OF ARCTIC AIR MOVE SOUTH FROM CANADA.

&&

.AVIATION /20Z-18Z/...

WARM ADVECTION WILL ALLOW MID LEVEL CLOUDS TO STREAM IN FOR PERIODS OF THE OVERNIGHT AS WINDS DECOUPLE. WINDS WILL BECOME SW TUESDAY WITH MIXING.

&&

.MARINE...

SMALL CRAFT ADVISORY IN EFFECT...WINDS EXPECTED TO DECOUPLE THIS EVENING.

12Z ETA/MAV MOS AT THOMAS POINT INDICATE SUSTAINED WINDS FALL BELOW 10KT THIS EVENING...AND INCREASE TO 15KT TUESDAY AFTERNOON. 12Z NAM/GFS PROXIMITY BUFKIT FORECAST SOUNDINGS SHOW ADDITIONAL MOMENTUM TRANSFER OF UP TO 25KT TUESDAY AFTERNOON.

WATER LEVELS ARE CURRENTLY ABOUT A HALF FOOT TO A FOOT BELOW ASTRONOMIC PREDICTIONS. THE LUNAR CYCLE IS WAXING TOWARD A FULL MOON IN EARLY FEBRUARY.

THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND THE NOAA EXTRATROPICAL STORM SURGE MODEL BOTH SUGGEST TIDAL DEPARTURES GRADUALLY RETURN TO ASTRONOMIC PREDICTIONS LATE TONIGHT AND TOMORROW MORNING.

&&

.LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR ANZ530>537.

SMALL CRAFT ADVISORY FROM 12 PM TUESDAY TO 12 PM EST WEDNESDAY FOR ANZ530>537.

&&

$$

SHORT TERM...ROGOWSKI LONG TERM...ROSA AVIATION...ROGOWSKI MARINE...ROGOWSKI

.SHORT TERM... WATER VAPOR LOOP SHOWS A TROUGH MOVING INTO THE ATLANTIC...AS THE NEXT UPPER LOW DROPS SOUTH INTO THE UPPER MIDWEST. ACARS 400-250MB WIND OBSERVATIONS REVEAL A NORTHWESTERLY 120-160KT JET FROM THE PLAINS THROUGH THE SOUTHEAST CONUS. 11Z SURFACE ANALYSIS PLACED THE ARCTIC BOUNDARY FROM A 1000MB OCCLUDED CYCLONE IN NORTHERN MINNESOTA EAST THROUGH THE UPPER GREAT LAKES AND NEW ENGLAND. A 1028MB ANTICYCLONE DOMINATED THE GULF STATES. A TROUGH WAS LOCATED IN LEE OF THE APPALACHIANS.

DRY AIRMASS IN PLACE AIDED BY DOWNSLOPE COMPONENT. WINDS WILL BE WANING DURING THE AFTERNOON AS BUILDING HEIGHTS ALLOWS A RIDGE TO BUILD INTO THE REGION. UPSLOPE SNOW SHOWERS WILL DIMINISH AS A RESULT.

VERY DRY 12Z KIAD RAOB (0.11" PRECIPITABLE WATER)...AND THUS BELIEVE IT WILL BE TOUGH TO GET CUMULUS GROWTH AS SUGGESTED BY THE 06Z NAM/GFS BUFKIT FORECAST SOUNDINGS. THE BEST CUMULUS GROWTH POTENTIAL WILL BE WEST OF THE BLUE RIDGE WHERE THERE IS SOME RESIDUAL UPSLOPE MOISTURE IN PLACE. SOME MID LEVEL MOISTURE WILL ARRIVE LATE IN THE DAY FROM THE WEST ON FAIRLY ZONAL FLOW ALOFT.

WENT BELOW MOS HIGH TEMPERATURE GUIDANCE GIVEN RECENT PERFORMANCE...STRONG COLD ADVECTION...AND THERMAL PROFILE OF 12Z KIAD RAOB.

&&

.AVIATION... GRADIENT WILL CONTINUE TO SUPPORT GUSTY WNW WINDS...TENDING TO SLACKEN DURING THE AFTERNOON AS THE HIGH BUILDS IN. BEST CHANCE FOR SCATTERED CUMULUS WILL BE WEST OF THE BLUE RIDGE...CLOSER TO THE UPSLOPE MOISTURE SOURCE.

&&

.MARINE... SMALL CRAFT ADVISORY IN EFFECT. 30KT WINDS WERE OBSERVED ATOP THE MIX LAYER ON THE 12Z KIAD RAOB.

00Z ETA/06Z MAV MOS AT THOMAS POINT INDICATE SUSTAINED WINDS AROUND 20KT DECREASE TO 15KT THIS AFTERNOON. 06Z NAM/GFS PROXIMITY BUFKIT FORECAST SOUNDINGS SHOW ADDITIONAL MOMENTUM TRANSFER OF UP TO 25KT THIS MORNING.

&&

.TIDES... WATER LEVELS ARE CURRENTLY ABOUT A HALF FOOT TO A FOOT BELOW ASTRONOMIC PREDICTIONS DUE TO A BLOWOUT. THE LUNAR CYCLE IS WAXING TOWARD A FULL MOON IN EARLY FEBRUARY.

THE CHESAPEAKE BAY OPERATIONAL FORECAST SYSTEM AND THE NOAA EXTRATROPICAL STORM SURGE MODEL BOTH SUGGEST TIDAL DEPARTURES GRADUALLY RETURN TO ASTRONOMIC PREDICTIONS LATE TONIGHT AND TOMORROW MORNING.

&&

.LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST MONDAY FOR ANZ530>537.

&&

$$

SHORT TERM/AVIATION/MARINE/TIDES...ROGOWSKI

.UPDATE... MAIN FCST CONCERN IS LOCATION/STRENGTH OF LES BANDS.

RADAR INDICATED A PROMINENT WEST TO EAST LES BAND FROM JUST SOUTH OF STANNARD ROCK TO WHITEFHISH POINT. SIGNFICANT LOW LVL CONVERGENCE WAS EVIDENT WITH W OR SW WINDS FROM MARQUETTE TO GRAND MARAIS AND NW WINDS FROM THE KEWEENAW AND STANNARD ROCK. OVER THE WEST...SFC OBS SUGGEST LOW LVL CONV WAS FOCUSED BETWEEN ONTONAGON AND KCMX. 00Z TAMDAR SNDG SHOWED TEMPS TO NEAR -19C AT 850 MB (5K FT) INVERSION WHILE UPSTREAM KDLH SNDG SHOWED A LOWER INVERSION(AROUND 900 MB) AND A SIGNIFICANTLY DRIER PROFILE.

MESO MODELS SHOWED SLIGHTLY DIFFERENT POSITION FOR BEST LOW LVL CONV AND LIKELY LOCATION FOR STRONGEST LES OVER THE WEST. THE NAM CONTINUED TO FOCUS LES BAND FARTHER NORTH...INTO HOUGHTON...THAN THE LAPS WRF-ARW (JUST N OF M-38) OR THE RUC13(SOUTH OF M-38). THE GOING FCST ADEQUATELY REFLECTS POTENTIAL FOR 3-6 INCH FROM ROCKLAND TO CALUMET. HOWEVER...ONLY MORE LOCALIZED HEAVIER AMOUNTS ARE EXPECTED...MOST LIKELY S OF HOUGHTON.

RADAR TREND AND MESO MODELS STILL SUGGEST SIGNFICANT LES POTENTIAL ALONG THE LAKE SUPERIOR SHORE E OF GRAND MARAIS THAT EVENTUALLY WOULD SAG FARTHER S INTO ERN ALGER COUNTY AND NRN LUCE COUNTY BY DAYBREAK. AGAIN...THERE IS LITTLE NEED AT THIS POINT TO ALTER GOING FCST AS POTENTIAL REMAINS FOR LOCAL 4-8 INCH AMOUNTS BY DAYBREAK.

&&

JLB

.PREV DISCUSSION...ISSUED 325 PM EST TUE JAN 30 2007

...ARCTIC AIR TO INVADE WEST AND CENTRAL UPPER MICHIGAN THIS WEEKEND...

.SYNOPSIS... 20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED UPPER TROUGHING COVERING MUCH OF SE CANADA INTO THE GREAT LAKES...WITH THE CENTER BEING A 498 DAM POLAR VORTEX OVER HUDSON BAY. ON THE WEST SIDE OF THE VORTEX WAS A SHRTWV OVER FAR NORTHERN ONTARIO... ACCOMPANIED BY A 90 KT JET STREAK NEAR THE TROPOPAUSE. THIS SHRTWV IS ALSO ASSOCIATED WITH A LOW PRESSURE TROUGH...WHICH EXTENDS FROM NE MANITOBA INTO NORTHERN ONTARIO JUST N OF PICKLE LAKE. ALTHOUGH 12Z SOUNDINGS FROM NEARBY CANADIAN RAOBS DO NOT INDICATE A LOT OF MOISTURE WITH THE SHRTWV...SURFACE OBS AND VISIBLE SATELLITE IMAGERY DOES SHOW A STRATUS DECK ALONG AND BEHIND THIS TROUGH...WITH OVERCAST CEILINGS BETWEEN 5000-8000 FT. EVEN A LITTLE LIGHT SNOW HAS BEEN REPORTED...WITH A 2 1/2 SM VISIBILITY RECENTLY AT PICKLE LAKE. 850MB TEMPS ARE STILL CHILLY NEAR THIS TROUGH...WITH THE PICKLE LAKE ONTARIO 12Z SOUNDING REPORTING AROUND -17C. CLOSER TO HOME...A 1018MB HIGH PRESSURE RIDGE AXIS IS BUILDING OVER UPPER MICHIGAN... WHICH EXTENDS WESTWARD TO A 1034MB HIGH CENTERED OVER NEBRASKA. THE COMBINATION OF DRIER AIR (SEE 12Z INL SOUNDING) AND DEVELOPING ANTICYCLONIC FLOW ASSOCIATED WITH THE SURFACE RIDGE HAS HELPED TO GREATLY DIMINISH THE LAKE EFFECT SNOW FROM WHAT OCCURRED LAST NIGHT. HOWEVER...WEAK RETURN FLOW ON THE BACK SIDE OF THE RIDGE AXIS HAS ALLOWED LAKE EFFECT TO RAPIDLY DEVELOP ON WESTERN LAKE SUPERIOR. FARTHER TO THE WEST...A STRONG SHRTWV CAN BE SEEN DIVING SOUTHWARD THROUGH SASKATCHEWAN ON THE EAST SIDE OF A VERY AMPLIFIED RIDGE WHEICH EXTENDS UP INTO ALASKA. ON THE NORTH SIDE OF THIS RIDGE OVER THE ARCTIC OCEAN IS YET A STRONGER SHRTWV...AND THIS IS THE ONE THAT WILL BRING THE ARCTIC AIR IN FOR THE WEEKEND.

&&

.SHORT TERM (TONIGHT AND WED)... MAIN FORECAST CONCERN IS LES WITH APPROACHING SHRTWV.

WINDS CONTINUING TO BACK TO THE WEST...ALONG WITH THE APPROACHING SHRTWV AND SURFACE TROUGHS...WILL SET UP AN INTERESTING SCENARIO FOR TONIGHT. AS TEMPERATURES COOL DOWN THIS EVENING IN THE INTERIOR AND OVER ONTARIO...LAND BREEZES ARE LIKELY TO SET UP. THESE LAND BREEZES WILL HELP TO FOCUS STRONG CONVERGENCE ALONG THE SURFACE TROUGH...WHICH IS PROGGED TO REACH THE KEWEENAW PENINSULA AND THE LAKE SUPERIOR SHORELINE NEAR GRAND MARAIS AROUND 03Z. THIS CONVERGENCE...COMBINED WITH PLENTY OF OVER-WATER INSTABILITY (AS NOTED WITH PICKLE LAKES RAOB) AND SYNOPTIC MOISTURE SHOULD HELP GENERATE SOME HEAVY LES...ESPECIALLY SINCE THE OMEGA INDUCED FROM THE LAKE EFFECT WILL INTERSECT A 50-75MB DEEP SNOW GROWTH LAYER PER MODEL SOUNDINGS. EXACTLY HOW STRONG THE LAND BREEZE IS WILL DICTATE HOW FAR SOUTH THE CONVERGENCE AND HEAVY SNOW GOES...PARTICULARLY IN THE WESTERN U.P. THE 13 KM RUC...WHICH HAS HAD A GOOD HANDLE ON LATEST LES EVENTS...SUGGESTS THE BAND WILL FOCUS IN THE AREA BETWEEN ROCKLAND AND BARAGA. HOWEVER THE NAM...REGIONAL CANADIAN AND LOCAL HIGH RESOLUTION WRF RUNS KEEP THE BAND FARTHER NORTH...ACROSS PAINESDALE AND HOUGHTON. THE LATEST 15Z AND 18Z RUC RUNS APPEAR TO BE FOLLOWING THE NAM SCENARIO TOO. SINCE ALL SOLUTIONS SEEM PLAUSIBLE...HAVE DECIDED TO FOLLOW A COMPROMISE. WHEREVER IT SETS UP...IT WILL LIKELY REMAIN NEARLY STATIONARY FOR 9 TO 12 HOURS BEFORE THE CONVERGENCE ZONE MOVES NORTHWARD...AND GIVEN GREAT SNOW GROWTH ON MODEL SOUNDINGS...DECIDED TO HOIST WARNINGS EARLIER FOR NE ONTONAGON AND NORTHERN HOUGHTON COUNTIES. ADVISORIES ARE POSTED FOR KEWEENAW AND SOUTHERN HOUGHTON FOR BOTH UNCERTAINTY REGARDING BAND PLACEMENT AND POSSIBLE OTHER BANDS THAT ARE AIDED BY UPSLOPE. KEWEENAW COUNTY WILL NEED TO BE WATCHED A LITTLE MORE TOMORROW AS THE CONVERGENCE ZONE MAY GET STUCK THERE. DECIDED NOT TO GO WITH A WARNING...THOUGH...AS THE CONVERGENCE WEAKENS DRAMATICALLY FROM THAT OBSERVED TONIGHT.

FOR THE EASTERN CWA...UPGRADED THE WATCH EARLIER TO A WARNING AS MODELS ARE IN GOOD AGREEMENT HERE WITH THE CONVERGENCE AREA. LOCAL HIGH RESOLUTION WRF RUN SUGGESTS UP TO 0.60 OF QPF UNDER THIS CONVERGENCE...WHICH GIVEN RECENT SNOW TO WATER RATIOS WOULD SUGGEST UP TO 18 INCHES OF SNOW. DID NOT GO THIS HIGH AT THE PRESENT TIME...BUT IT WOULD NOT BE A SURPRISE IF AMOUNTS THAT HIGH OCCUR...ESPECIALLY GIVEN EXTRA CONVERGENCE HELP FROM LAND BREEZES OFF ONTARIO.

AWAY FROM THE LES DURING THE SHORT TERM PERIOD...CONDITIONS LOOK FAIRLY QUIET. ALTHOUGH THE STRATUS DECK OVER ONTARIO IS EXPECTED TO MOVE OVER THE CWA THIS EVENING...MUCH OF THE SHRTWV FORCING WHICH HAS HELPED PRODUCE THE LIGHT SNOW AT PICKLE LAKE IS PROGGED TO MOVE OFF TO THE E. THEREFORE HAVE REMOVED ANY SLIGHT CHANCE POPS FOR SYNOPTIC SNOW. ALSO REMOVED POPS FOR SYNOPTIC SNOW ON WED SINCE MUCH OF THE CWA IS PROGGED TO BE IN WEAK SHRTWV RIDGING BETWEEN TONIGHTS SHRTWV AND THE SASKATCHEWAN SHRTWV TROUGH.

GOING FORECAST TEMPERATURES THROUGH WED LOOK REASONABLE AND HAVE MADE VERY FEW CHANGES TO THEM.

.LONG TERM (WED NIGHT THROUGH NEXT TUE)... ON WED NGT...SHRTWV TROF/DEEPER MSTR WL BE PUSHING TO THE E WED NGT...AND GUIDANCE SHOWS LLVL FLOW VEERING MORE W OVERNGT W-E IN ITS WAKE AND GRDLY BECMG MORE ACYC WITH APRCH OF SHRTWV RDGING/DNVA/ H85-5 QVECTOR DVGC. THESE EVENTS SHOULD CAUSE LES BANDS NEAR THE TIP OF THE KEWEENAW TO MIGRATE TO THE S IN LINE WITH GFS/NAM FCST SHARPER LLVL CNVGC. HOWEVER...SHIFTING WINDS/MORE TRANSIENT CNVGC/ NEGATIVE DYNAMICS MIGHT LIMIT SN ACCUMULATION WED NGT. WL GO WITH LIKELY POPS OVER THE W FM ONTONAGON COUNTY TO THE N. SINCE GUIDANCE SHOWS FOCUSED LLVL CNVGC REMAINING TO THE N OF THE ERN ZNS...WL GO WITH JUST CHC POPS NR LK SUP E OF P53. OTRW...ANY PTCHY -SN/ FLURRIES ACCOMPANYING SHRTWV WL TEND TO DIMINISH OVERNGT ONCE DEEPER MSTR/DYNAMICS EXIT TO THE E. PREFER LOWER GOING FCST MIN TEMPS WITH PROSPECT OF DRYING ALF LATE AS SHOWN ON GFS FCST SDNGS EVEN THOUGH BKN-OVC SC SHOULD LINGER UNDER DVLPG SUBSIDENCE INVRN.

EXPECT A RELATIVELY QUIET DAY ON THU UNDER WEAK SHRTWV RDG DOWNSTREAM OF A DEEPENING TROF IN THE NRN PLAINS AND LLVL FLOW SLOWLY BACKING MORE SW. EVEN THOUGH QUITE A BIT OF SC WL LINGER UNDER MID LVL DRY AIR/SUBSIDENCE INVRN SHOWN ON GFS FCST SDNGS....WL RESTRICT MENTION OF POPS ON THU TO AREAS DOWNWIND OF LK SUP IN EXPECTED WSW FLOW. PREFER SOMEWHAT LOWER GFS MOS TEMPS GIVEN EXPECTED CLD COVER/H85 TEMPS -15C TO -17C OR SO.

AS SHRTWV FM THE NRN PLAINS MOVES INTO THE UPR MS VALLEY BY 12Z FRI AND THEN INTO ERN LK SUP BY 00Z FRI ACCOMPANINED BY SOME FAIRLY HEALTHY DPVA/H85-5 QVECTOR CNVGC/12 HR H5 HGT FALLS APRCHG 80M... EXPECT A RELATIVELY WDSPRD SN TO DVLP...WITH THE HEAVIEST SN FALLING OVER THE NW HALF OF THE FA ON CYC SIDE OF H5 VORT TRACK WHERE LLVL NW FLOW WL OFFER THE OPPORTUNITY FOR SOME LK ENHANCEMENT AS H85 TEMPS TUMBLE IN THE AFTN AND GFS FCST SDNGS SHOW DEEP MSTR THRU THE TROP. DECIDED TO BUMP POPS UP TO LIKELY EVERYWHERE WITH CATEGORICAL POPS FM IWD-CMX-HURON MTNS ON FRI. LATER SHIFTS WL LIKELY NEED TO ISSUE HEADLINE FOR THIS EVENT EVEN THOUGH LATEST NCEP FCST SN AMTS JUST A FEW INCHES.

BITTER COLD WL BE THE MAIN WX STORY THIS WEEKEND/EARLY NEXT WEEK IN PERSISENT HI AMPLITUDE NEGATIVE NAO/POSTIVE PNA DEEP UPR TROF CENTERED BTWN ERN PAC RDG NOSING INTO AK AND BLOCKING UPR HI IN THE N ATLANTIC OCEAN. ALTHOUGH THERE ARE SOME SLGT TIMING DIFFERENCES... 00Z>12Z MID RANGE GUIDANCE IN FAIRLY GOOD AGREEMENT WITH 0Z GFS REFCST ENSEMBLE MEAN DEPICTING SFC LO CROSSING LK SUP ON FRI (SEE ABV) IN ADVANCE OF INCOMING WAVE OF ARCTIC AIR. CORE OF ARCTIC COLD WITH H85 TEMPS IN THE -28C TO -32C RANGE FCST BY BOTH 06Z GFS/12Z ECMWF TO INVADE SAT AND PERSIST INTO TUE. GFS REFCST ENSEMBLE MEAN SHOWS AVERAGE H1000-5 THKNS ARND 488DM WITH H85 TEMPS FCST IN EXCESS OF 2 STANDARD DEVIATIONS BLO NORMAL. AS A COMPARISON TO RECENT COLD WAVES...H85 TEMPS IN THE EARLY FEB 1996 COLD WAVE WERE -30C TO -35C...SO THIS EVENT MAY END UP MARGINALLY WARMER THAN THE COLD OBSVD IN EARLY FEB 1996. GIVEN AGREEMENT AMONG OPS MODELS/ENSEMBLE MEAN...WL GO TOWARD THE LO END OF GFS MOS GUIDANCE FOR THE WEEKEND/EARLY NEXT WEEK... WITH SOME MIN TEMPS AOB -30F/MAX TEMPS REMAINING BLO 0F A GOOD BET FOR INTERIOR AREAS. ALTHOUGH LES WL BE ONGOING NR LK SUP WITH CORE OF COLD PASSING OVER LK SUP ESPECIALLY IN NW FLOW BELTS TO THE S OF LK INDUCED TROF NR LK SUP...SUCH FRIGID TEMPS WL NOT BE CONDUCIVE FOR FVRBL SN GROWTH.

COORDINATED WITH GRB.

&&

.MQT WATCHES/WARNINGS/ADVISORIES...

LAKE EFFECT SNOW WARNING 7 PM THIS EVENING TO 1 PM WED MIZ002-003 LAKE EFFECT SNOW WARNING 10 PM THIS EVENING TO 1 PM WED MIZ006-007 LAKE EFFECT SNOW ADVISORY 7 PM THIS EVENING TO 1 PM WED MIZ001 LAKE EFFECT SNOW ADVISORY 7 PM THIS EVENING TO 10 AM WED MIZ084 HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR.

&&

$$

AJ (SHORT TERM) KC (LONG TERM)

.AVIATION... COLD FRONT HAS PUSHED THROUGH ALL TAF SITES AS OF LATE MORNING AND WILL RESULT IN A NORTH WIND BETWEEN 10 TO 15 KTS THROUGH MID DAY. VISIBILITIES HAVE DROPPED AT KAMA TO AROUND 5SM AT TIMES IN BR BUT IT APPEARS ON VISIBLE SATELLITE THAT THIS WILL BE SHORT LIVED. HAVE PLACED VISIBILITIES DROPPING TO 6SM IN A TEMPO GROUP THROUGH 19Z... BUT THIS SHOULD NOT AFFECT AIRCRAFT OPERATIONS. MIST SHOULD CLEAR OUT AS NORTH WIND ADVECTS A BIT DRIER AIR INTO THE REGION AND AS THE MID AND HIGH LEVEL CLOUD SHIELD MOVES JUST SOUTH OF THE AREA.

JORDAN

&&

.PREV DISCUSSION... /ISSUED 553 AM CST MON JAN 29 2007/

AVIATION... COLD FRONT WILL PUSH THROUGH THE AVIATION FORECAST SITES THIS MORNING...SHIFTING WINDS BACK FROM THE NORTH THEN NORTHEAST. SUSTAINED SPEEDS SHOULD STAY BELOW 15 KT WITH GUSTS AS HIGH AS 20 KT. TEMPERATURE DEWPOINT DEPRESSION IS LOW...AND MAY RESULT IN SOME PATCHY FOG. DID NOT MENTION FOG IN THE NEW TAF PACKAGE SINCE THE FRONT ARRIVES AND DEPLETES LOW LEVEL MOISTURE.

NUNEZ

PREV DISCUSSION... /ISSUED 357 AM CST MON JAN 29 2007/

DISCUSSION... NOT MUCH REASON TO CHANGE THE PREVIOUS FORECAST. MEAN LONGWAVE TROUGH WILL CONTINUE TO BE SITUATED OVER THE CENTRAL U.S. CAUSING SEVERAL COLD FRONTS TO MOVE THROUGH THE PANHANDLES REGION. THE FIRST FRONT WILL MOVE THROUGH THE AREA TODAY KEEPING TEMPS IN CHECK. MID AND UPPER LEVEL MOISTURE JUST DOES NOT APPEAR TO BE ENOUGH TO WARRANT DECENT CHANCES FOR PRECIP. FORECAST SOUNDINGS SUGGEST THAT THE COLUMN SHOULD BE COLD ENOUGH FOR ALL SNOW BUT WE HAVE BEEN DOWN THAT PATH BEFORE AND GOTTEN BURNED...WENT AHEAD AND LEFT PRECIP TYPE AS SNOW FOR NOW BUT WOULD NOT BE SURPRISED TO SEE SOME SLEET OR FREEZING RAIN MIXED IN INITIALLY. FAVORED PRECIP AREAS WILL BE IN THE WESTERN COUNTIES TONIGHT THANKS TO OROGRAPHIC LIFTING...THEN WILL SPREAD EAST TO ENCOMPASS THE WHOLE PANHANDLES AS LIGHT ISENTROPIC LIFT TAKES OVER. AGAIN LIFT IS WEAK SO LEFT POPS AT SLT CHC.

ANOTHER FRONT IS EXPECTED WEDNESDAY KEEPING HIGHS IN THE 30S TO LOWER 40S. BEST CHANCE FOR PRECIP AT THIS TIME LOOKS LIKE WED NIGHT INTO THU WITH THE FRONT JUST SOUTH OF THE AREA AND A DECENT UPPER LEVEL DISTURBANCE MOVING ACROSS THE AREA. CURRENTLY HAVE HIGH TEMPS IN THE MID TO UPPER 30S THU BUT THIS MAY BE TOO WARM IF PRECIP EXTENDS INTO THU AFTERNOON.

GFS AND ECMWF BOTH SHOWING STRONGEST SURGE OF COLD AIR WILL BE THU NIGHT INTO FRI MORNING WITH H85 TEMPS LESS THAN -10C MAKING IT INTO THE AREA. THIS WILL BRING ANOTHER PROLONGED PERIOD OF TEMPS BELOW FREEZING STRETCHING FROM FRI MORNING INTO SUN MORNING. THIS COLD PUSH DOES NOT APPEAR AS POTENT AS THE ONE WE HAD A COUPLE OF WEEKS AGO DUE TO THE LACK OF A STRONG UPPER LOW DIGGING TO THE WEST. THE S/W TROF PUSHING THE FRONT THROUGH REMAINS WELL TO THE NORTH OF THE AREA AND WILL KEEP THE COLD AIRMASS SOMEWHAT SHALLOW. OROGRAPHIC LIFT MAY HELP DEVELOP SOME PRECIP FRI NIGHT INTO SAT BUT THE LACK OF MID AND UPPER LEVEL MOISTURE SHOULD KEEP IT AS FREEZING DRIZZLE OR LIGHT FLURRIES AND THUS HAVE NOT YET ADDED POPS FOR THIS TIME FRAME.

MODELS ARE SHOWING YET ANOTHER COLD SURGE MOVING THROUGH THE AREA ON SUNDAY THOUGH THE GFS AND ECMWF ARE QUITE DIFFERENT ON ITS STRENGTH. THE 29/00Z GFS HAS MORE NORTHWESTERLY UPPER FLOW AND THUS TAKES MOST OF THE COLD AIR TO THE EAST. THE 29/00Z ECMWF IS MORE AMPLIFIED AND BRINGS MORE COLDER AIR INTO THE SOUTHERN HIGH PLAINS...HOWEVER THIS IS DIFFERENT FROM THE 28/12Z WHICH MORE CLOSELY RESEMBLED THE LATEST GFS. SO UPPED TEMPS SLIGHTLY SUNDAY IN CASE THE COLDEST AIR DOES MISS US TO THE EAST...BUT AM STILL A GOOD 7-10F BELOW GUIDANCE.

HENNIG

AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE.

$$

&&

.AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE.

&&

$$

99/99

.SYNOPSIS...A STRONG RIDGE OF HIGH PRESSURE WILL DOMINATE THE WEATHER THROUGH THE END OF THE WEEK...CONTINUING THE DRY SPELL AND PRODUCING COLD NIGHTS. THE RIDGE WILL WEAKEN BY FRIDAY AND A WEAK WEATHER SYSTEM WILL BRING A CHANCE OF RAIN TO WESTERN WASHINGTON OVER THE WEEKEND.

&&

.SHORT TERM...THE MAIN QUESTION FOR TODAY IS HOW MUCH LOW LEVEL MIXING WILL OCCUR. ACARS SOUNDINGS INDICATE THE TOP OF THE INVERSION AROUND 2K FT WITH FOG DEPTH REMAINING QUITE SHALLOW NEAR THE SFC. N/NE GRADIENTS SHOULD BE ENOUGH TO MIX THIS OUT BY THIS AFTERNOON...EXCEPT PERHAPS SHELTERED PARTS OF THE SW INTERIOR. NE WINDS ARE ALREADY PICKING UP TO OVER 10 KT THROUGH THE INVERSION LAYER GIVING BETTER CONFIDENCE THIS WILL HAPPEN. TEMPS SHOULD RUN A GOOD 5-8 DEGREES WARMER OVER YESTERDAY SO THE FORECAST APPEARS ON TRACK. WILL ALSO LET THE CURRENT AIR STAGNATION ADVISORY EXPIRE THIS MORNING.

FOG WILL REFORM TONIGHT BUT SHOULD REMAIN MORE PATCHY AS A GOOD NE BREEZE WILL HELP LIMIT INVERSIONS. A COUPLE VERY NICE DAYS OF TAP FOR WED AND THU UNDER DRY NLY FLOW ALF. THE LATEST GFS STILL SLIDES A 1035 MB SFC HIGH FROM BC TO E OF THE CASCADES ON THU. ITS A LITTLE UNCERTAIN HOW MUCH COLD AIR MAKES IN OVER THE TERRAIN INTO WRN WA...BUT IT DOES APPEAR WE COOL OFF A FEW DEGREES AT 850 AND FILTER IN SOME DRIER AIR. THIS SHOULD ALLOW FOR SLIGHTLY COOLER TEMPS...THOUGH ELY WINDS SHOULD PICK UP PRETTY GOOD KEEPING TEMPS FROM REALLY BOTTOMING OUT OVERNIGHT. DRY WEATHER CONTINUES INTO FRI.

NEW 12Z MODELS ARE HANDLING THE WEEKEND SYSTEM DIFFERENT THAN YESTERDAYS RUNS. MAY NEED TO MAKE SOME ADJUSTMENTS THIS AFTERNOON AFTER COORDINATION. DTM

&&

.LONG TERM...PREVIOUS DISCUSSION FOLLOWS...FRI WILL BE MORE OF THE SAME. WE COULD FINALLY BEGIN TO SEE A CHANCE OVER THE WEEKEND...WITH THE LONGER RANGE MODELS IN ROUGH AGREEMENT THAT A WARM FRONT WILL MOVE THROUGH THE RIDGE AND BRING SOME LIGHT PCPN TO THE AREA. THIS IS UNCERTAIN STILL...AND THE CURRENT CHANCE WORDING IN THE EXTENDED FORECAST IS GOOD FOR NOW. MCDONNAL

&&

.AVIATION...ONLY AREAS OF FOG THIS MORNING ARE CONFINED TO A VERY THIN SURFACE LAYER AND WILL DISSIPATE MOST AREAS BY 18Z. MDT N OR NELY FLOW WILL PERSIST THROUGH THE DAY.

AT KSEA...MINOR THREAT THAT FOG TO NE OF KSEA COULD DRIFT SOUTH OVER FIELD PRIOR TO DISSIPATING HAS ENDED. EXPECT NLY WINDS OF 10-15 KT WITH SOME HIGHER GUSTS MIDDAY.

&&

.MARINE...THE OFFSHORE OR NORTHERLY GRADIENT IS STRONG ENOUGH FOR LOW END SMALL CRAFT ADVISORY SPEEDS VICINITY W ENTRANCE TO THE STRAIT AND BRIEFLY FOR THE PUGET SOUND/HOOD CANAL AREAS FOR TODAY.

STILL ON TRACK FOR STRONGER NELY GRADIENTS ON THU WITH NELY GALES POSSIBLE IN THE STRAIT AND NORTHERN INLAND WATERS.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...SMALL CRAFT ADVISORY COASTAL WATERS...WEST ENTRANCE TO THE STRAIT OF JUAN DE FUCA...AND PUGET SOUND/HOOD CANAL.

$$

.DISCUSSION... WINTER WEATHER TO CONTINUE ACROSS THE AREA...

09Z SFC ANALYSIS SHOWS A COLD FRONT STRETCHING WEST TO EAST OVER THE GREAT BASIN INTO AN AREA OF LOW PRES OVER SOUTHERN CO. A STNRY BNDRY IS DRAPED ACROSS THE E PLAINS OF NM. LATEST WV LOOP SHOWS THE SOUTHERN STREAM UPPER LOW OVER SOCA PUSHING EAST TOWARD THE BAJA AS A NORTHERN STREAM UPPER TROUGH SWINGS SOUTH ACROSS THE NORTHERN ROCKIES. IR SAT IMG SHOWS STRONG CLOUD TOP COOLING WITH UPPER DIVERGENCE INCR OVER SE CO AND NE NM. 400-200MB AIRCRAFT WINDS SHOW A 80-100 KNOT JET DIVING SOUTH BEHIND THE NORTHERN STREAM UPPER LOW AND A 130 KNOT JET STNRY ACROSS TEXAS.

00Z MREF ALONG WITH 00Z GFS/NAM/ECMWF/UKMET INDICATE THE TWO UPPER LEVEL SYSTEMS WILL PHASE OVER E AZ AND NM WED AFTERNOON AND DEEPEN INTO A LARGE SCALE UPPER TROUGH OVER THE CENTRAL US. EXPECTING NMRS RAIN/SNOW SHOWERS TO CONTINUE TODAY ESPECIALLY ALONG WEST FACING SLOPES OF THE NORTHERN AND WESTERN MTNS. ACTIVITY WILL INCR IN INTENSITY TOWARD DUSK WITH H5 HEIGHT FALLS AND INCREASING MID LEVEL LAPSE RATES. HAVE EXTENDED THE CURRENT SNOW ADVISORIES UNTIL 12Z THU FOR MOST AREAS WITH MODELS CONTINUING TO SQUEEZE OUT MOISTURE ACROSS THE REGION. 00Z NAM ALSO SUGGESTING AREA OF GOOD CSI TO SET UP ACROSS NE PLAINS OF NM AS STRONG COLD FRONT PRESSES SOUTH ACROSS THE REGION. MODEL CROSS SECTION INDICATES STRONG FRONTOGENESIS TO DEVELOP BELOW LAYER OF NEGATIVE EPV WITHIN A SATURATED COLUMN. WILL ISSUE A SNOW ADVISORY FOR NM ZONES 5...6...AND 7 TO COVER SNOWFALL THERE THRU 12Z.

MODELS CONTINUE TO SHOW COLD AIR MOVING INTO THE STATE FROM THURSDAY THROUGH THE WEEKEND...ESPECIALLY ACROSS THE E PLAINS. WENT WELL BELOW GUIDANCE PARTICULARLY DURING THE OVERNIGHT HOURS AS SNOWPACK AND CLEAR SKIES WILL CREATE STRONG RADIATIONAL COOLING. BEYOND THE WEEKEND IT APPEARS A SLOW WARM UP TO NEAR AVERAGE TEMPS AS RIDGING BUILDS OVER THE SW CONUS.

&&

.PRELIMINARY POINT TEMPS/POPS... FARMINGTON...................... 39 18 34 16 / 60 50 10 20 GALLUP.......................... 35 15 34 14 / 60 70 30 20 GRANTS.......................... 36 16 35 13 / 60 60 20 20 GLENWOOD........................ 43 29 46 26 / 50 60 40 20 CHAMA........................... 24 5 25 0 / 80 50 20 40 LOS ALAMOS...................... 33 18 34 14 / 60 60 20 20 RED RIVER....................... 22 5 22 -3 / 80 70 20 30 TAOS............................ 33 12 29 7 / 70 60 20 30 SANTA FE........................ 32 19 30 16 / 50 60 20 20 SANTA FE AIRPORT................ 34 20 32 18 / 50 50 20 20 ESPANOLA........................ 36 24 35 14 / 60 50 20 20 ALBUQUERQUE HEIGHTS............. 39 26 36 24 / 40 30 10 10 ALBUQUERQUE VALLEY.............. 41 24 38 21 / 40 30 10 10 ALBUQUERQUE FOOTHILLS........... 34 22 32 20 / 40 40 10 10 ALBUQUERQUE WEST MESA........... 37 25 35 23 / 40 40 10 10 SOCORRO......................... 44 30 44 24 / 40 20 10 5 SANDIA PARK/CEDAR CREST......... 32 20 30 17 / 50 60 20 20 MORIARTY/ESTANCIA............... 36 22 35 13 / 40 50 10 10 CARRIZOZO....................... 40 27 40 21 / 30 20 20 5 RUIDOSO......................... 35 24 33 23 / 40 40 30 20 RATON........................... 32 9 30 4 / 40 60 20 20 LAS VEGAS....................... 33 13 31 9 / 40 60 20 10 ROY............................. 32 14 30 13 / 30 60 20 10 CLAYTON......................... 28 11 25 10 / 30 60 20 30 SANTA ROSA...................... 41 22 40 22 / 30 50 20 5 TUCUMCARI....................... 37 19 36 17 / 30 60 30 10 FORT SUMNER..................... 39 24 43 21 / 20 50 20 5 CLOVIS.......................... 36 24 39 23 / 20 50 30 10 PORTALES........................ 38 25 41 22 / 20 40 30 10 ROSWELL......................... 44 29 40 29 / 20 20 10 5

&&

.ABQ WATCHES/WARNINGS/ADVISORIES... SNOW ADVISORY UNTIL 5 AM MST THURSDAY FOR THE FOLLOWING ZONES... NMZ001>004-008-010-011-014-016-017-026.

SNOW ADVISORY FROM 6 PM THIS EVENING TO 5 AM MST THURSDAY FOR THE FOLLOWING ZONES...NMZ005>007.

SNOW ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR THE FOLLOWING ZONES...NMZ009.

&&

$$

GUYER

.SYNOPSIS...A STRONG UPPER RIDGE WILL REMAIN CENTERED JUST OFF THE WASHINGTON COAST THIS WEEK WITH SURFACE HIGH PRESSURE ENTRENCHED EAST OF THE CASCADES. OFFSHORE FLOW WILL MAINTAIN MODERATE EAST WINDS NEAR THE COLUMBIA RIVER GORGE THROUGH WEDNESDAY MORNING. OFFSHORE FLOW WILL DECREASE WEDNESDAY AFTERNOON BUT CONTINUE THROUGH THE WEEK AS THE UPPER RIDGE PERSISTS. THE DRY WEATHER MAY NOT LAST THROUGH THE WEEKEND AS THE HIGH PRESSURE MAY BE DISPLACED BY THE WESTERLY JET STREAM APPROACHING THE WEST COAST.

&&

.SHORT TERM...A STRONG RIDGE OF HIGH PRESSURE ALOFT REMAINS ANCHORED OFFSHORE OF THE PACIFIC NORTHWEST BY AN UPPER LEVEL LOW WEST OF CALIFORNIA. THE UPPER LEVEL LOW WILL CONTINUE TO MOVE EASTWARD INTO SOUTHERN CALIFORNIA TONIGHT AND WEDNESDAY. THE BLOCKING PATTERN WILL PERSIST AS THE RIDGE ALOFT AMPLIFIES. WEATHER WILL REMAIN DRY WITH SEVERAL SHORTWAVES DROPPING SOUTH DOWN THE EAST SIDE OF THE UPPER RIDGE.

PORTLAND-THE DALLES GRADIENT HOLDING STEADY AT ABOUT -7 MB BRINGING PEAK GUSTS TO AROUND 35 TO 40 MPH NEAR THE WESTERN GORGE. 18Z AND 00Z WRF MODEL ARE LOOKING LESS FAVORABLE FOR WIND ADVISORY FOR EASTERN CLARK AND MULTNOMAH COUNTIES THAN YESTERDAYS RUNS BUT WILL STILL BRING WINDY CONDITIONS. WILL HAVE TO WATCH MORNING AIRCRAFT SOUNDINGS FOR STRONG INVERSION AND LOWER LEVEL WINDS THAT MAY SURFACE.

.LONG TERM...NO CHANGES. PREVIOUS DISCUSSION FOLLOWS... MODELS CONTINUE TREND OF RIDGE EVENTUALLY BEING UNDERCUT BY SUNDAY...WITH DRY WEATHER THROUGH SATURDAY. WILL CONTINUE CURRENT FORECAST OF CHANCE OF RAIN NORTH SUNDAY AS MODELS CONTINUE TO INDICATE A WARM FRONT MOVE OVER THE TOP OF THE TRUNCATED RIDGE AND BRUSH WASH AND NW OREGON. WEATHER WILL STAY DRY FROM THURSDAY THROUGH SATURDAY NIGHT. LOOKS DRY AGAIN UNTIL THE MIDDLE OF NEXT WEEK...WHEN MODELS HINT AT WESTERLIES WILL UNDERCUT THE RIDGE. A VERY STRONG 200 MB WINDS IN THE WESTERN PACIFIC MAY BE HARBINGER FOR THIS POTENTIAL CHANGE IN THE PATTERN.

&&

.AVIATION...HIGH PRESSURE BUILDING EAST OF THE CASCADES FOR MOSTLY CLEAR SKIES AND LIGHT WINDS. THE EXCEPTION TO THIS BEING LOW CLOUDS EAST OF CASCADE LOCKS AND INCREASING EAST WINDS THROUGH AND JUST WEST OF THE GORGE.

&&

.MARINE...OFFSHORE FLOW WILL REMAIN BELOW SCA THROUGH WED. SEAS NEAR 6 FT TONIGHT AND WEDNESDAY.

.PQR WATCHES/WARNINGS/ADVISORIES .OR/WA......NONE.

&&

.PRELIMINARY POINT POPS... AST 001110 PDX 001110 SLE 0011100 EUG 001100 $$

MORE WEATHER INFORMATION ONLINE AT... Http://weather.gov/portland

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.

.SYNOPSIS...DEPARTING UPPER LEVEL LOW PRESSURE AND RESIDUAL MOISTURE WILL CAUSE A FEW LINGERING SHOWERS INTO THURSDAY MORNING. PARTLY CLOUDY AND A LITTLE WARMER THURSDAY AFTERNOON THROUGH FRIDAY IN DRIER NORTHWEST FLOW ALOFT. MOSTLY CLEAR AND MUCH WARMER THIS WEEKEND AND EARLY NEXT WEEK UNDER HIGH PRESSURE WITH WEAK OFFSHORE FLOW.

&&

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

.SHORT TERM (TODAY-SAT)...THERE WAS VARIABLE CLOUDINESS TODAY WITH ISOLATED SHOWERS...MAINLY W OF THE MOUNTAINS. ACARS SOUNDINGS HAD W TO NW WINDS IN THE LOW LEVELS AND STRONG NE WINDS ALOFT. ONSHORE GRADIENTS WITH 3-4 MB SAN-IPL.

THE UPPER LOW WILL MOVE E OUT OF THE AREA THIS EVENING FOLLOWED BY NW TO N FLOW ALOFT THROUGH FRI. THERE WILL CONTINUE TO BE LOW LEVEL MOISTURE INTO THU FOR PARTLY CLOUDY SKIES WITH POSSIBLE UPSLOPE AND ISLAND EFFECT SHOWERS. THE CHANCE OF PRECIP WILL GENERALLY TAPER OFF AND TEND TO BE CONFINED TO SAN DIEGO COUNTY THROUGH THU MORNING. JUST SLIGHT WARMING THU. THE FLOW ALOFT WILL BECOME DRIER OUT OF THE N FRI WITH OFFSHORE GRADIENTS DEVELOPING FOR A LITTLE MORE WARMING AND DECREASING CLOUDINESS. STRONG UPPER LEVEL HIGH PRESSURE WILL BE JUST OFF THE W COAST AND THERE WILL BE WEAK OFFSHORE FLOW SAT FOR MOSTLY CLEAR SKIES AND A WARMER DAY.

.LONG TERM (SUN-WED)...STRONG HIGH PRESSURE ALOFT AND OFFSHORE FLOW FOR MOSTLY CLEAR SKIES AND MORE WARMING EARLY NEXT WEEK. THE HIGH ALOFT AND OFFSHORE FLOW WILL SLOWLY WEAKEN THROUGH THE MIDDLE OF NEXT WEEK FOR GRADUAL COOLING.

&&

.AVIATION... UNSETTLED CONDITIONS ARE EXPECTED TO CONTINUE THROUGH THE NIGHT IN THE UNSTABLE AIR MASS BEHIND THE UPPER LOW THAT MOVED ONSHORE EARLIER THIS MORNING. EXPECT MULTIPLE CU AND STRATOCU LAYERS THROUGH TONIGHT WITH THE LOWEST SCATTERED TO BROKEN LAYER AROUND 1500 FEET WITH ADDITIONAL BROKEN LAYERS AROUND 3000 FEET AND 5000 FEET. SCATTERED SHOWERS WILL REDUCE VISIBILITIES TO MVFR CONDITIONS AT TIMES. ONSHORE FLOW WILL KEEP CLOUDS IN THURSDAY MORNING BUT SHOULD BECOME SCATTERED DURING THE AFTERNOON ON THURSDAY.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...

HIGH SURF ADVISORY FOR SAN DIEGO COASTAL AREAS FROM 2 AM THU THROUGH 2 AM SAT. SEE LAXCFWSGX.

&&

$$

PUBLIC...DVA AVIATION...HORTON

.SYNOPSIS...A STRONG UPPER RIDGE WILL REMAIN JUST OFFSHORE FOR THE REST OF THE WEEK WITH SURFACE HIGH PRESSURE ENTRENCHED EAST OF THE CASCADES. THE RIDGE ALOFT WILL GRADUALLY BEGIN TO BREAK DOWN THIS WEEKEND EVENTUALLY ALLOWING A CHANCE FOR PRECIPITATION BACK INTO THE AREA BY EARLY NEXT WEEK.

&&

.SHORT TERM...THE HIGH AMPLITUDE BLOCKING RIDGE ALOFT WILL REMAIN STATIONARY JUST OFFSHORE OF THE PACIFIC NORTHWEST BRINGING DRY WEATHER THROUGH THE END OF THE WEEK. CONDITIONS THIS MORNING LOOK FAVORABLE FOR MOUNTAIN WAVE DEVELOPMENT SO ISSUED A WIND ADVISORY THIS MORNING FOR AREAS DOWNWIND OF THE COLUMBIA RIVER GORGE. CURRENTLY THERE IS A 9.1 MB PRESSURE DIFFERENCE BETWEEN ASTORIA AND THE DALLES. THE PORTLAND TO THE DALLES PRESSURE DIFFERENCE JUST INCREASED ABOVE THE TROUTDALE TO THE DALLES DIFFERENCE INDICATING THAT THE LEESIDE MESO LOW NEAR THE EXIT REGION OF THE GORGE HAS STARTED TO SHIFT TO THE WEST. ACARS SOUNDINGS THIS MORNING SHOW 40 KT EASTERLIES ABOVE THE PORTLAND AIRPORT WITH A CRITICAL LAYER AROUND 800 MB WHERE THE WINDS SHIFT FROM EASTERLY TO LIGHT NORTHERLY. WITH ALL THESE PIECES IN PLACE AND THE OFFSHORE FLOW EXPECTED TO INCREASE JUST A LITTLE MORE THIS MORNING SURFACING MOUNTAIN WAVES LOOK LIKELY. I EXPECT TO SEE THE STRONGEST WINDS CURRENTLY IN THE WESTERN COLUMBIA RIVER GORGE AND TROUTDALE AREA TO SHIFT EAST TO AROUND THE PORTLAND AIRPORT AND I-250 BRIDGE AREA BY MID MORNING.

MODELS SHOW THE PRESSURE GRADIENT ACROSS THE MOUNTAINS DECREASING RAPIDLY THIS AFTERNOON. WHILE I EXPECT THIS TO OCCUR MORE SLOWLY AND LATER IN THE DAY...THE TREND LOOKS REASONABLE. THEREFORE WE SHOULD SEE THE WINDS SLACKING THIS EVENING. A SHORTWAVE TROUGH ALOFT ACCOMPANIED BY A COLD SURFACE HIGH FROM NORTHWEST CANADA WILL MOVE DOWN THE EAST SIDE OF THE RIDGE ALOFT AND INTO THE ARE ON THURSDAY. OFFSHORE WINDS WILL INCREASE SHARPLY THURSDAY AFTERNOON AND EVENING BRINGING FALLING TEMPERATURES. COOLER TEMPERATURES AND STRONG EAST WINDS THROUGH THE GORGE WILL PERSIST THROUGH FRIDAY. RUTHFORD.

.LONG TERM...GENERAL PATTERN TO REMAIN BASICALLY UNCHANGED AT THE BEGINNING OF THE EXTENDED TIME FRAME (SAT). MEDIUM RANGE MODELS MAINTAIN STRONG UPPER RIDGE NEAR OR JUST OFF THE COAST. APPEARS THE MODELS ARE DELAYING ANY PATTERN CHANGE UNTIL EARLY NEXT WEEK. TUESDAY GFS RUNS SHOWED THE RIDGE BEGINNING TO WEAKEN SUN. NOW...IT APPEARS THE RIDGE WILL HOLD FIRM THROUGH SUN. ALL MAJOR MODELS (GFS/CANADIAN/ECMWF/NOGAPS ETC) KEEP THE RIDGE INTACT SUN. CURRENT GRIDS SHOW CHANCE-TYPE POPS SUN. THIS WILL NEED TO BE LOOKED AT AND WILL LIKELY TONE THOSE DOWN FOR THE AFTERNOON FORECAST. HARD TO IMAGING THE RIDGE MOVING ANYWHERE WITH SUCH A STRONG HUDSON BAY LOW. EVENTUALLY...SOMETHING WILL HAVE TO GIVE AND MODELS DO INDICATE THE RIDGE WEAKENING MON. GFS AND ECMWF GRUDGINGLY SLIDE THE RIDGE AXIS EAST MON AS SOME SORT OF SYSTEM TRIES TO SLIDE IN FROM THE SW. HOWEVER...MAY GET AWAY WITH A DRY DAY MON AS WELL. BEYOND MON LOOKS LIKE A TREND TOWARD CLIMATOLOGY WOULD BE THE BEST BET. GFS AND ECMWF FAIRLY SIMILAR ON TUE GRADUALLY MOVING THE RIDGE AXIS FURTHER EAST. CONFIDENCE FOR DAYS 6-7 NOT THAT IMPRESSIVE AT THE MOMENT BASED ON ENSEMBLE CHARTS. WEISHAAR

&&

.AVIATION...HIGH PRESSURE EAST OF THE CASCADES WILL MAINTAIN MODERATE TO STRONG EAST WINDS NEAR THE WEST END OF THE GORGE INTO THIS AFTERNOON. THE HIGH WILL THEN SHIFT EASTWARD WITH DECREASING EAST WINDS. OTHERWISE CLEAR SKIES AND LIGHT WINDS THROUGH THU. &&

.MARINE...GAP WINDS WILL CONTINUE THIS MORNING WITH A FEW GUSTS ABOVE 21 KT BUT WILL HOLD OFF ON SCA. OFFSHORE FLOW WILL DECREASE THIS AFTERNOON. SEAS WILL REMAIN NEAR 6 FT.

&&

.PQR WATCHES/WARNINGS/ADVISORIES .OR/WA...WIND ADVISORY TODAY FOR EASTERN SECTIONS OF THE NORTHERN WILLAMETTE VALLEY AND THE GREATER VANCOUVER AREA. &&

.PRELIMINARY POINT POPS... AST 00000 PDX 00000 SLE 00000 EUG 00000 $$

MORE WEATHER INFORMATION ONLINE AT... HTTP://WEATHER.GOV/PORTLAND

THIS DISCUSSION IS FOR NORTHWEST OREGON AND SOUTHWEST WASHINGTON FROM THE CASCADE CREST TO 60 NAUTICAL MILES OFFSHORE. THE AREA IS COMMONLY REFERRED TO AS THE FORECAST AREA.

.SHORT TERM...TONIGHT/THURSDAY. HIGH CIRRUS COVERED MOST OF THE REGION THROUGHOUT THE DAY...WITH AN INCREASE IN CLOUDS ACROSS THE SW PART OF THE CWA. VERY DRY AIR HAS BEEN LINGERING OVER NE WI...WITH DEWPOINTS AT OR BELOW ZERO. -SN OVER EASTERN MN HAS BEEN STARTING TO SPREAD INTO WRN WI DURING THE MID AFTERNOON...WITH THE DRY AIR SEEMING TO BE WEAKENING THE INITIAL EASTWARD EXTENT OF THE PCPN. DEW POINTS HAVE BEEN GRADUALLY INCREASING OVER WESTERN WI...IN ADVANCE OF PCPN.

SHORT WAVE TROUGH DIVING SOUTHEAST OUT OF MN AT THIS TIME. PCPN APPEARS TO BE LOCATED IN PROXIMITY OF BEST LIFT FROM THE VORT...WHICH LOOKS TO PUSH SE ACROSS SRN WI THIS EVENING. EXISTING DRY AIR OVER THE REGION AROUND H700...COMBINED WITH MORE WSW FLOW DUE TO FLATTENING...WILL LIMIT THE NORTHWARD EXTENT OF THE MOISTURE PUSH. 12Z GRB AND 20Z CWA TAMDAR SOUNDING SHOW PLENTY OF DRY AIR THAT NEEDS TO BE OVERCOME. NAM FORECAST SOUNDING ONLY SHOWING VERY SHORT PERIOD OF DEEP MOISTURE THIS EVENING... BEFORE H500-800 DRY AIR PUSHES IN. EXPECT BEST CHANCE OF LIGHT SNOW ACROSS SRN HALF OF CWA THIS EVENING...WITH PCPN CHANCES TAPERING OFF FARTHER TO THE NORTH. HAVE BUMPED POPS UP ACROSS SRN HALF OF CWA TO REFLECT THIS. HAVE QUESTIONS ON THE AMOUNT OF MEASURABLE PRECIP...AS MODELS ARE PRETTY CONSISTENT ON ONLY 0.01 TO 0.02 QPF. WITH COLDER TEMPS AND HIGH SNOW RATIO...ABOUT 18-1...EXPECT SNOWFALL AMOUNTS TO TOP OUT AROUND 0.5 IN.

BEST H700 MOISTURE SHIFTS EAST OF THE REGION SHORTLY AFTER MIDNIGHT... WITH LINGERING H850-925 MOISTURE THROUGH THE FIRST HALF OF THURSDAY. SFC TROUGH LOOKS TO PUSH ACROSS CWA BETWEEN 06Z AND 09Z...SO HAVE LEFT PCPN CHANCES FOR MAINLY FLURRIES ACROSS SE HALF OF CWA UNTIL TROUGH PUSHES THROUGH. BACK SIDE OF SYSTEM IN ND AND MN SEEING SOME FLURRIES AND LIGHT SNOW...BUT BELIEVE IT WAS ASSOCIATED WITH BEST LIFT WITH SHORT WAVE.

WEAK RIDGE BUILDS OVER THE REGION FOR THURSDAY...COMBINED WITH DECEASING MOISTURE...EXPECT A SLIGHT DECREASE IN CLOUDS OVER THE REGION...BEFORE STARTING TO INCREASE OVER FAR NW PART OF CWA AS NEXT SHORT WAVE AND ASSOCIATED MOISTURE APPROACH THE REGION. HAVE WENT WITH TEMPS CLOSE TO GUIDANCE VALUES AND GFS AND NAM IN PRETTY GOOD AGREEMENT.

AVAIATION...EXPECT SOME MVFR CONDITIONS THIS EVENING AS THE TROUGH AND SHORT WAVE PUSH ACROSS NE WI. SW LOW LEVEL WINDS WILL INCREASE DURING THE EVENING...BUT WITH INCREASE IN SFC WINDS...SHOULD BE ENOUGH TO OFFSET WIND SHEAR POSSIBILITY.

.LONG TERM...THURSDAY NIGHT THROUGH NEXT WEDNESDAY. SNOW ASSOCIATED WITH A SURFACE LOW AND COLD FRONT IS THE MAIN CONCERN FOR THURSDAY NIGHT INTO FRIDAY. AFTER THAT...TEMPERATURES AND POTENTIAL LAKE EFFECT SNOW ARE THE FORECAST FOCUS.

AN APPROACHING COLD FRONT COMBINED WITH A MID LEVEL TROUGH AND INCREASING MOISTURE WILL BRING SNOW INTO THE REGION FOR THURSDAY NIGHT AND FRIDAY. HAVE ACCELERATED THE ONSET OF PCPN FROM THE PREVIOUS FORECAST SINCE 12Z GFS HAD QPF ACROSS THE ENTIRE AREA BY 12Z FRIDAY. 12Z NAM/WRF IS A BIT SLOWER WITH QPF BUT FAST ENOUGH TO JUSTIFY POPS ON THURSDAY NIGHT. PCPN CHANCES CONTINUE ON FRIDAY AS THE COLD FRONT AND MID LEVEL TROUGH BOTH PASS THROUGH THE AREA. A SURFACE TROUGH AND ANOTHER MID LEVEL SHORT WAVE WILL KEEP CLOUDS IN THE AREA ALONG WITH SOME FLURRIES FRIDAY NIGHT. THE AIRMASS BEHIND THE SYSTEM IS EXPECTED TO BE QUITE COLD AS IT ENTERS THE REGION. 1000-500 MB THICKNESSES BELOW 5 KFT ALONG WITH 850 MB TEMPERATURES OF -22 C OR COLDER. AM EXPECTING LOWS AROUND OR COLDER THAN GUIDANCE LOWS FOR FRIDAY NIGHT. HAVE A CHANCE OF SNOW SHOWERS IN VILAS AND ONEIDA COUNTIES THEN. DID NOT GO WITH LIKELY POPS SINCE 850 MB WINDS ARE NOT THAT FAVORABLE FOR LAKE EFFECT IN THE AREA. HAVE CHC POPS ON SATURDAY WITH ANOTHER MID LEVEL SHORT WAVE. EXPECT EVEN COLDER TEMPERATURES SATURDAY NIGHT AS CAA CONTINUES...SO HAVE CUT SEVERAL DEGREES OFF GUIDANCE LOWS THEN AND SUNDAY NIGHT. TEMPERATURES SHOULD GRADUALLY WARM DURING THE REST OF THE FORECAST PERIOD...BUT WILL STILL BE WELL BELOW NORMAL. WINDS GENERALLY NOT IN A FAVORABLE DIRECTION FOR LES.

&&

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

$$ MG/SRF WEATHER.GOV/GREENBAY