Forecast Discussions mentioning "ACARS", "MDCRS", "AIRCRAFT", "TAMDAR", or "AMDAR" received at FSL on 02/28/07


AREA FORECAST DISCUSSION
NWS SAN DIEGO CA
230 PM PST TUE FEB 27 2007 .SYNOPSIS... RESIDUAL MOISTURE AND UPPER LEVEL LOW PRESSURE WILL CONTINUE SHOWERS THROUGH WEDNESDAY ALONG WITH LOCAL STRONG GUSTY WINDS IN THE MOUNTAINS AND DESERTS. PARTLY CLOUDY THURSDAY IN DRIER NORTHWEST FLOW. FAIR AND WARMER THIS WEEKEND UNDER HIGH PRESSURE. COOLER WITH MORE CLOUDS EARLY NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (TONIGHT-FRI)... THE COLD FRONT BROUGHT MODERATE TO BRIEFLY HEAVY SHOWERS EARLIER TODAY. EARLY AFTERNOON ACARS SOUNDINGS SHOWED VERY STRONG WLY WINDS ALOFT. ONSHORE GRADIENTS WITH ABOUT 6 MB SAN-IPL AND 11 MB SAN-TPH AND THERE WERE LOCAL STRONG GUSTY WINDS IN THE MOUNTAINS AND DESERTS. SHOWERS THROUGH WED IN MOIST CYCLONIC FLOW ALOFT COMBINED WITH ISLAND EFFECT AND OROGRAPHICS. A SECONDARY VORT MAX COULD CAUSE ANOTHER PERIOD OF MODERATE SHOWERS TONIGHT TURNING TO SCT SHOWERS AND GENERALLY TAPERING OFF WED. THE WINDS ALOFT AND ONSHORE GRADIENTS WILL CAUSE LOCAL STRONG GUSTY WINDS...ESPECIALLY NEAR THE MOUNTAIN RIDGES AND TO A LESSER EXTENT IN THE DESERTS. LOCAL REDUCED VISIBILITY IN THE DESERTS DUE TO BLOWING DUST. RAINFALL TOTALS SHOULD RANGE FROM UP TO ABOUT HALF AN INCH AT THE COAST TO ONE AND ONE HALF INCH ON THE COASTAL SLOPES. HOURLY RAINFALL RATES OF UP TO ONE HALF INCH PER HOUR WILL BE POSSIBLE THIS MORNING AND AGAIN TONIGHT. SNOW LEVEL NEAR 4500 TO A LITTLE BELOW 4000 FT WED MORNING WITH AREAS OF BLOWING SNOW AND DENSE FOG IN THE MOUNTAINS. DRIER NW FLOW ALOFT WITH HIGHER HEIGHTS THU AND FRI FOR DECREASING CLOUDS AND WINDS AND A LITTLE WARMER DAYS. HOWEVER...THERE COULD BE A BRIEF INCREASE IN CLOUDINESS FRI AFTERNOON AS A WEAK SHORT WAVE MOVES THROUGH. .LONG TERM (SAT-TUE)... HIGH PRESSURE ALOFT AND OFFSHORE FLOW THIS WEEKEND FOR FAIR AND WARMER WEATHER WITH LOCAL BREEZY CONDITIONS THROUGH AND BELOW MOUNTAIN CANYONS AND PASSES. A UPPER TROUGH WILL BRING MORE CLOUDS AND COOLING EARLY NEXT WEEK. && .AVIATION... 272100Z...INITIAL COLD FRONT NOW EAST OF THE AREA WITH MAIN UPPER TROUGH AXIS WELL OFF THE COAST THIS AFTERNOON. SKIES HAVE SCATTERED OVER THE COASTAL WATERS...BUT THE DEEP MOIST LAYER AND INSTABILITY OVER LAND HAS KEPT CLOUDS ON THE FOOTHILLS AND BACKED UP AGAINST THE COASTAL SLOPES. CIGS SHOULD REMAIN SCATTERED TO BROKEN W OF THE FOOTHILLS UNTIL AFTER 08Z...THEN THICKEN AND LOWER WITH AREAS OF CIGS BETWEEN 1.5K AND 3K FT MSL AND VISIBILITY 3-5SM IN SHOWERS THROUGH 15Z ASSOCIATED WITH SECOND WEAK COLD FRONT AND PASSAGE OF MAIN UPPER TROUGH AXIS. CLOUDS AND PRECIPITATION WILL REMAIN BACKED UP ALONG THE COASTAL SLOPES THROUGH WED OBSCURING THE TERRAIN...DUE TO CONTINUED STRONG ONSHORE FLOW. FREEZING LEVEL SHOULD DROP TO FL040 AFTER 03Z. WINDS WEST 15 TO 25 KT BELOW FL050...INCREASING TO 27040KT NEAR FL100. THE STRONG WESTERLY WINDS WILL CAUSE MOUNTAIN WAVE/ROTOR ACTIVITY WITH STRONG UDDFS OVER THE MOUNTAINS AND IN THE DESERTS THROUGH WEDNESDAY. SURFACING WAVE ACTIVITY EAST OF THE CRESTS COULD GENERATE SEVERE TURBULENCE WITH LOCAL SURFACE WIND GUSTS IN EXCESS OF 50 KT...AND REDUCED VISIBILITY IN AREAS OF BLOWING DUST IN THE DESERTS. && .SGX WATCHES/WARNINGS/ADVISORIES... HIGH WIND WARNING UNTIL 10 PM PST WEDNESDAY FOR THE HIGHER MOUNTAINS AND DESERTS. SEE LAXNPWSGX. SNOW AND BLOWING SNOW ADVISORY UNTIL 10 PM WEDNESDAY FOR THE HIGHER MOUNTAINS. SEE LAXWSWSGX. && $$ PUBLIC...DVA AVIATION...JAD
AREA FORECAST DISCUSSION...UPDATED
NWS MOUNT HOLLY NJ
930 PM EST TUE FEB 27 2007 .UPDATE... A MID LEVEL SHORT WAVE WAS PASSING OVERHEAD THIS EVENING. THE APPROACHING SHORT WAVE HAS BEEN ENHANCING AN AREA OF LIGHT SNOW IN NORTHEASTERN PENNSYLVANIA SINCE EARLY THIS EVENING. MEANWHILE, ANOTHER AREA OF LIGHT PRECIP WAS BLOSSOMING OVER THE MIDDLE DELMARVA REGION. BOTH THE NAM AND THE GFS ARE INDICATING LIGHT MEASURABLE PRECIP IN THAT AREA THROUGH ABOUT MIDNIGHT. IT SHOULD BE IN THE FORM OF LIQUID, SO WE`VE INCLUDED SCATTERED RAIN SHOWERS FOR OUR FAR SOUTHERN COUNTIES UNTIL AROUND MIDNIGHT. FOR THE AREA BETWEEN THE SNOW IN THE NORTH AND THE RAIN SHOWERS IN THE SOUTH, WE`VE SIMPLY GONE WITH SCATTERED SPRINKLES UNTIL AROUND MIDNIGHT WITH THE MENTION OF SOME FLURRIES AS WELL TO THE NORTH OF PHL. RECENT ACARS DATA FROM THE PHL REGION INDICATED THAT THE FREEZING LEVEL WAS UP AROUND 2500 FEET AT 9:00 PM. WITH THE LIGHT INTENSITY OF THE PRECIP, IT SHOULD REACH THE GROUND AS LIQUID FOR THE MOST PART. IN THE WAKE OF THE MID LEVEL SHORT WAVE THERE IS ANOTHER WEAK IMPULSE DROPPING DOWN IN THE NORTHWEST FLOW. THAT FEATURE SHOULD PASS OVER OUR FORECAST AREA AROUND DAYBREAK. AS A RESULT, WE`VE KEPT THE MENTION OF SCATTERED FLURRIES FOR THE HOURS AFTER MIDNIGHT AS THE ATMOSPHERE COOLS A BIT. HOWEVER, ANY PRECIP MAY STILL FALL AS LIQUID IN OUR FAR SOUTHERN COUNTIES AT THAT TIME, SO WE`VE WORDED THE FORECAST ACCORDINGLY. AS FAR AS TEMPS ARE CONCERNED, WE`VE RAISED THEM A FEW NOTCHES IN THE GRIDS FOR THE VERY NEAR TERM. THE FORECAST MINIMA CONTINUED TO SEEM REASONABLE. $$ .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...NONE. DE...NONE. MD...NONE. MARINE...NONE. && $$ UPDATE...IOVINO
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
606 AM CST MON FEB 26 2007 .DISCUSSION... 313 AM CST THE 1500 METER AGL WIND PLOT SHOWS THE CENTER OF THE CIRCULATION OVER EASTERN WISCONSIN BETWEEN SHEBOYGAN AND MILWAUKEE. THE SURFACE LOW WAS OVER MILWAUKEE AT 08 UTC. THE ACARS SOUNDING AT ORD AT 0601 UTC SHOWS SOME VEERING BELOW 1.2 KILOMETERS. THERE IS STILL SOME WARM AIR ADVECTION IN THE LOWEST LAYER OF THE ATMOSPHERE. THERE IS SOME AREAS OF LIGHT PATCHY FOG IN THE MORNING. WATER VAPOR LOOP SHOWS THIS CIRCULATION HAS BEEN DRIFTING NORTH. THIS CIRCULATION OR UPPER AIR LOW IS FORECAST TO MOVE NORTH AND JOIN THE CIRCULATION OF A 500 MB LOW CENTERED OVER NEWFOUNDLAND. THAT WILL OCCUR THURSDAY NIGHT. THE SURFACE LOW WILL MOVE INTO MICHIGAN AND SLOWLY DISSIPATE. BY MONDAY EVENING THE LOW LEVEL WIND FROM THE SURFACE TO 1.2 KILOMETER ARE EXPECTED TO BECOME WESTERLY. THIS IS SEEN ON THE LOCAL WRF ARW MODEL FORECAST. THE TEMPERATURE DEWPOINT SPREAD IS EXPECTED TO REMAIN VERY LOW THROUGH THIS EVENING. WE EXPECT THE SKY TO BE OVERCAST WITH A CHANCE OF LIGHT SNOW SHOWERS TODAY. THERE WILL BE SOME FOG THIS MORNING. THERE IS VERY WET SNOW AND WATER ON THE GROUND WILL ADD TO THE LOW LEVEL MOISTURE. A GRADUAL CLEARING OF THE SKY WILL TAKE PLACE TUESDAY AND TUESDAY NIGHT. A HIGH MOVES INTO THE REGION. BOTH THE GFS AND WRF BRING A 500 MB RIDGE INTO ILLINOIS BY EARLY WEDNESDAY MORNING. ON THURSDAY A TROUGH MOVES INTO THE GREAT PLAINS WITH A SURFACE CYCLONE IN WESTERN MISSOURI. THE HIGH TEMPERATURE ON THURSDAY IS EXPECTED TO CLIMB INTO THE MIDDLE 40S. THERE WILL BE RAIN ON THURSDAY AS THE CYCLONE MOVES INTO IOWA. THIS CYCLONE WILL MOVE INTO WISCONSIN BY FRIDAY MORNING. THE CURRENT FORECAST REFLECTS THIS SYNOPTIC TREND THROUGH THE WEEK. ONLY MADE SOME MINOR ADJUSTMENTS ON THE TEMPERATURE FORECAST AND WEATHER FORECAST. && .AVIATION... 606 AM CST DRIZZLE FALLING AT KMDW AND KGYY EXPECTED TO END IN THE NEXT FEW HOURS AS TREND UPSTREAM HAS BEEN IMPROVING VISIBILITY. IR SATELLITE LOOP SHOWS A WEAK MID LEVEL CIRCULATION OVER SOUTHERN MN WHILE COMPOSITE RADAR LOOP AND SURFACE OBS PLOTS SHOW AN AREA OF LIGHT SNOW EXTENDING ACROSS NORTHEAST IA AND SW WI. 06Z GFS RUN INITIALIZED THE CIRCULATION WELL AND INDICATES THAT THIS MINOR DISTURBANCE WILL WEAKEN AS IT MOVES INTO NORTHERN IL THIS AFTERNOON...SIMILAR TO 00Z MODEL OUTPUT SHOWED. EXPECT SNOW OCCURING UPSTREAM TO SPREAD ACROSS TERMINALS MID-LATE MORNING BUT DECREASING IN INTENSITY. LIGHT SNOW TO END LATE AFTERNOON AS MINOR WAVE MOVES ACROSS NORTHEAST IL. LOW LEVEL MOISTURE REMAINS TRAPPED UNDER INVERSION TONIGHT SO EXPECT MVFR CEILINGS TO PREVAIL WITH MODEL SOUNDINGS SHOWING BASE OF INVERSION AROUND 3000FT AGL. SURFACE LOW PRESSURE NEAR KMKE WILL CONTINUE TO VERY GRADUALLY WEAKEN AND MOVE NORTHEASTWARD TO WEST CENTRAL LOWER MI BY 00Z TUE. THIS WILL MAINTAIN W TO WSW SURFACE WINDS ACROSS THE TERMINALS THRUOUGH THE PERIOD. TRS && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
313 AM CST MON FEB 26 2007 .DISCUSSION... THE 1500 METER AGL WIND PLOT SHOWS THE CENTER OF THE CIRCULATION OVER EASTERN WISCONSIN BETWEEN SHEBOYGAN AND MILWAUKEE. THE SURFACE LOW WAS OVER MILWAUKEE AT 08 UTC. THE ACARS SOUNDING AT ORD AT 0601 UTC SHOWS SOME VEERING BELOW 1.2 KILOMETERS. THERE IS STILL SOME WARM AIR ADVECTION IN THE LOWEST LAYER OF THE ATMOSPHERE. THERE IS SOME AREAS OF LIGHT PATCHY FOG IN THE MORNING. WATER VAPOR LOOP SHOWS THIS CIRCULATION HAS BEEN DRIFTING NORTH. THIS CIRCULATION OR UPPER AIR LOW IS FORECAST TO MOVE NORTH AND JOIN THE CIRCULATION OF A 500 MB LOW CENTERED OVER NEWFOUNDLAND. THAT WILL OCCUR THURSDAY NIGHT. THE SURFACE LOW WILL MOVE INTO MICHIGAN AND SLOWLY DISSIPATE. BY MONDAY EVENING THE LOW LEVEL WIND FROM THE SURFACE TO 1.2 KILOMETER ARE EXPECTED TO BECOME WESTERLY. THIS IS SEEN ON THE LOCAL WRF ARW MODEL FORECAST. THE TEMPERATURE DEWPOINT SPREAD IS EXPECTED TO REMAIN VERY LOW THROUGH THIS EVENING. WE EXPECT THE SKY TO BE OVERCAST WITH A CHANCE OF LIGHT SNOW SHOWERS TODAY. THERE WILL BE SOME FOG THIS MORNING. THERE IS VERY WET SNOW AND WATER ON THE GROUND WILL ADD TO THE LOW LEVEL MOISTURE. A GRADUAL CLEARING OF THE SKY WILL TAKE PLACE TUESDAY AND TUESDAY NIGHT. A HIGH MOVES INTO THE REGION. BOTH THE GFS AND WRF BRING A 500 MB RIDGE INTO ILLINOIS BY EARLY WEDNESDAY MORNING. ON THURSDAY A TROUGH MOVES INTO THE GREAT PLAINS WITH A SURFACE CYCLONE IN WESTERN MISSOURI. THE HIGH TEMPERATURE ON THURSDAY IS EXPECTED TO CLIMB INTO THE MIDDLE 40S. THERE WILL BE RAIN ON THURSDAY AS THE CYCLONE MOVES INTO IOWA. THIS CYCLONE WILL MOVE INTO WISCONSIN BY FRIDAY MORNING. THE CURRENT FORECAST REFLECTS THIS SYNOPTIC TREND THROUGH THE WEEK. ONLY MADE SOME MINOR ADJUSTMENTS ON THE TEMPERATURE FORECAST AND WEATHER FORECAST. && .AVIATION DISCUSSION FOR 06Z TAFS... 1100 PM CST SFC LOW OVER SRN WI CONTINUES FILLING AND MOVING TOWARD MIKE OVERNIGHT. NEW BAND OF SNOW INTENSIFIED THIS EVENING AND IS SWEEPING EAST THRU COOK CNTY TO NW INDIANA. REMAINDER OF NIGHT SHUD HAVE MORE MVFR TO VFR VSBY. HOWEVER IFR CIGS ADVECTING ACRS NRN IL FROM IA ON WEST WINDS WRAPPING AROUND SFC LOW IN SRN WI. HOWEVER CIGS QUITE VARIABLE FROM IFR TO HIGH MVFR AND DIFFICULT TO COVER ALL BASES OF CIGS THRU NEXT 24 HRS. HAVE OPTED TO BRING CIGS UP TO MVFR BFR MRNG AND REMAIN THERE THRU 06Z AS CYCLONIC FLOW AROUND THIS SLOW MOVING SFC LOW CONTINUES INTO TUESDAY. THIS SFC LOW TRACKS SLOWLY ACRS SRN LK MICH MON MRNG TO SWRN MICH BY EVENING...THEN TO CNTL LOWER MICH BY 06Z MON NGT. FLURRIES OR SNOW SHOWERS WILL ALSO PLAGUE TERMINALS ALTHO VSBY SHUD NOT DROP TO IFR. WEST TO SW WINDS GENERALLY 10 TO 12 KTS SHUD PREVAIL THRU 06Z. RLB && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...NONE. .IN...NONE. .LM...NONE. && $$
AREA FORECAST DISCUSSION
NWS MARQUETTE MI
1020 PM EST TUE FEB 27 2007 .UPDATE... TRANQUIL EVENING IS UNDERWAY ACROSS FCST AREA UNDER CLOUDY SKIES/LIGHT WINDS. KMQT RADAR SUGGESTS THERE ARE STILL SOME FLURRIES OCCURRING OVER PARTS OF THE FCST AREA...BUT THAT MAY NOT BE ALL THERE WILL BE FOR PCPN DURING THE OVERNIGHT. THE POTENTIAL OF FZDZ IS THE MAIN FCST ISSUE JUST AS IT WAS LAST NIGHT. 00Z KGRB SOUNDING SHOWED MOISTURE EXTENDING TO JUST -11C...RAISING CONCERN FOR FZDZ. MEANWHILE...PIREPS THIS EVENING FROM FLIGHTS OVER KESC/KIMT INDICATE CLOUD TOPS IN THE 7-8.4KFT RANGE. THIS IS ROUGHLY SIMILAR TO 18Z NAM FCST SOUNDINGS FOR THIS EVENING. ACCORDING TO NAM FCST SOUNDINGS...TEMPS SHOULD BE AS LOW AS -15C WITHIN THAT MOISTURE DEPTH...AND THAT ACTUALLY MATCHES WELL WITH TAMDAR SOUNDINGS FROM KSAW THIS EVENING. 18Z GFS/NAM FCST SOUNDINGS SUGGEST TOP OF THE MOISTURE LAYER OVER THE SCNTRL/SW FCST AREA WILL THIN SOME DURING THE NIGHT WHICH MAY BE SUFFICIENT TO TAKE MOISTURE DEPTH OUT OF THE COLDER AIR TO AROUND -10C...SIMILAR TO 00Z KGRB SOUNDING. HOWEVER... SINCE CIGS IN GENERAL HAVE RISEN DURING THE LATE AFTN AND EVENING (THERE ARE NO IFR CIGS ACROSS FCST AREA RIGHT NOW)...WILL HOLD OFF ON ANY FZDZ MENTION. A FEW BREAKS IN THE CLOUD DECK ARE SHOWING UP IN NRN WI AND ADJACENT UPPER MI...SO THERE MAY BE SOME PATCHY RADIATION FOG DEVELOP OVER THE SW PART OF FCST AREA WHERE CLOUDS BREAK FOR A TIME. AS FOR TEMPS...WILL BUMP MINS UP SLIGHTLY IN MOST LOCATIONS BASED ON CURRENT SFC DWPT READINGS AND EXPECTED CLOUD COVER. && .PREV DISCUSSION (ISSUED AT 430 PM EST)... ...SIGNIFICANT SNOWFALL POSSIBLE WED NIGHT INTO SAT... SYNOPSIS... 20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A WEAKENING UPPER LEVEL TROUGH FROM NORTHERN MN INTO LOWER MI... RIDGING BUILDING OVER THE PLAINS...AND A LARGE TROUGH MOVING INTO THE WESTERN STATES. AT THE BASE OF THIS TROUGH WAS A 150KT JET NEAR 200MB MOVING INTO SOUTHERN CALIFORNIA. IN FACT...THERE HAVE BEEN QUITE A FEW LIGHTNING STRIKES ASSOCIATED WITH THE TROUGH...SOME OVER WYOMING AND OTHERS IN OREGON AND NORTHERN CALIFORNIA. THIS TROUGH WILL BE THE MAIN FEATURE OF INTEREST FOR THE SIGNIFICANT SNOW LATER THIS WEEK. IN THE MEANTIME...CONDITIONS ARE FAIRLY QUIET ACROSS THE CWA WITH ONLY A FEW FLURRIES OCCURRING PER OBSERVATIONS AND LATEST RADAR LOOP. THESE FLURRIES ARE ASSOCIATED WITH WEAK DYNAMICS AND MID LEVEL MOISTURE ASSOCIATED WITH THE UPPER LEVEL TROUGH. ALTHOUGH LAST NIGHT THERE WERE REPORTS OF FREEZING DRIZZLE IN NORTHERN LOWER MI WITH THE SATURATED LAYER UP TO -14C...IT APPEARS NOW THAT THERE IS ENOUGH ACTIVATED ICE NUCLEI TO KEEP THE PRECIP TYPE AS SNOW...AS NOTED BY OBSERVATIONS THROUGH THE DAY TODAY. VISIBLE SATELLITE IMAGERY SHOWS PLENTY OF LOW CLOUDS...MAINLY MVFR-VFR VARIETY... COVERING MUCH OF THE WESTERN GREAT LAKES REGION...EXCEPT OVER NE LAKE SUPERIOR AND THE EASTERN U.P. WHERE DRIER NE FLOW HAS KEPT THEM AT BAY. DESPITE ALL THE CLOUD COVER...TEMPERATURES HAVE STILL MANAGED TO REACH AROUND THE 30 DEGREE MARK...WHICH IS NEAR NORMAL. AT THE SURFACE...PRESSURES ARE BEGINNING TO FALL OVER THE WESTERN SIDE OF THE PLAINS SINCE THE UPPER RIDGE AXIS IS OFF TO THE EAST. MEANWHILE...1035MB HIGH PRESSURE STILL SITS UP NEAR HUDSON BAY AND IT APPEARS IT WILL NOT BE MOVING ANYTIME SOON....WHICH WILL BE A FACTOR IN THE BREEZY CONDITIONS LATE THIS WEEK. SHORT TERM (TONIGHT AND WED)... AS THE SAYING GOES...THE QUIET BEFORE THE STORM. UPPER LEVEL RIDGING OVER THE PLAINS WILL BUILD TOWARDS UPPER MICHIGAN DURING THIS PERIOD...DUE TO THE WESTERN TROUGH MOVING FARTHER INLAND. THUS THE MID-LEVEL TROUGH OVER NORTHERN MN INTO LOWER MI IS PROGGED TO LIFT NORTH ACROSS THE CWA TONIGHT INTO TOMORROW MORNING. WEAK DYNAMICS WITH THE TROUGH ALONG WITH PLENTY OF LOW TO MID LEVEL MOISTURE SHOULD KEEP SOME SCATTERED FLURRIES GOING ACROSS MUCH IF NOT ALL OF THE CWA THROUGH WED MORNING. HAVE EVEN KEPT FLURRY CHANCES GOING INTO WED AFTERNOON SINCE A STRATUS DECK REMAINS PRESENT...HOWEVER WITH THE DYNAMICS LEAVING...THE AFTERNOON MAY END UP MOSTLY DRY. THE PREVIOUS FORECAST HAD SOME CHANCE POPS LATE ALONG THE WISCONSIN BORDER DUE TO WARM AIR ADVECTION ON THE BACK SIDE OF THE RIDGE. HAVE REMOVED MOST OF THESE SINCE THE ADVECTION IS SLOWER...HOWEVER THE GFS STILL DEPICTS THE POSSIBILITY FOR SOME LAKE ENHANCED LIGHT SNOW OVER THE SOUTH CENTRAL FROM LAKE MICHIGAN. HAVE LEFT THE PREVIOUS FORECAST LOW TEMPERATURES FOR TONIGHT ALONE AS THEY SEEM REASONABLE GIVEN PLENTY OF CLOUD COVER. COOLEST READINGS ARE EXPECTED IN LUCE COUNTY WHERE THERE ARE A FEW HOLES IN THE CLOUD DECK WHICH WOULD ALLOW FOR BETTER RADIATIONAL COOLING. SINCE THE AIRMASS ON WED LOOKS SIMILAR TO THAT OF TODAY...HAVE RAISED HIGH TEMPERATURES CLOSE TO OR JUST SLIGHTLY ABOVE TODAYS READINGS. LONG TERM(WED NIGHT THROUGH TUE)... MAIN FCST CONCERNS ARE SNOW/WIND POTENTIAL WITH THE STORM MOVING FROM THE PLAINS TOWARD THE GREAT LAKES. THE 12Z GFS AND ITS ENSEMBLE MEMBERS HAVE CONTINUED TO TREND TOWARD A MORE SRLY LOW TRACK THAN PREVIOUS RUNS. THE 00Z/12Z ECMWF HAS REMAINED FAIRLY CONSISTENT WITH KEEPING THE LOW FARTHER TO THE WEST BY 12Z FRI(WRN WI) WHILE THE UKMET IS FARTHEST SOUTH(ERN IA). MDLS CONSENSUS SFC AND UPPER LEVEL LOW POSITION SIMILAR TO THE CANADIAN GLOBAL WOULD BE OVER NE IA BY 00Z/FRI FAR SW WI BY 12Z AND TOWARD CNTRL OR NRN LK MI BY 00Z/SAT. WITH THE LOW DEEPENING TO AROUND 980 MB VERY STRONG E OR ENE WINDS ARE ALSO EXPECTED. WED NIGHT INTO THU...SIMILAR TO THE LAST STORM...EXPECT SIGNIFICANT SNOWFALL DURING A COUPLE OF SEPARATE SURGES. THE INITIAL BATCH OF WAA AND STRONG 280K-295K ISENTROPIC LIFT WILL MOVE IN LATE WED NIGHT INTO THURSDAY MORNING WITH MIXING RATIO VALUES OF 4 G/KG AVBL. A FAIRLY TIGHT MOISTURE GRADIENT IS ALSO EXPECTED ON THE LEADING EDGE OF THE SNOWFALL AS WITH DRY ERLY FLOW STILL IN PLACE INTO E UPPER MI. THE GOING WATCH WAS DELAYED SLIGHTLY TO ACCOUNT FOR THE SLOWER ARRIVAL OF ACCUMULATING SNOW. WATCHES WERE ALSO ADDED FOR MOST OF THE REST OF UPPER MI EVEN THOUGH SNOWFALL DURING THE DAY THU MAY ONLY FALL INTO THE 2-5 INCH RANGE CNTRL OR NORTH. THU NIGHT... AS THE LOW DEEPENS AND EDGES TOWARD THE AREA...VERY STRONG MOISTURE TRANSPORT FROM THE SOUTH AND EAST AS WOULD BE EXPECTED IN THE TROWAL REGION OF A STRONG OCCLUDED LOW. EVEN THOUGH THE GFS HAS TRENDED TOWARD A COLDER PROFILE WITH THE LOW TRACK FARTHER SOUTH...CANNOT RULE OUT POSSIBILITY OF AN ELEVATED WARM LAYER NEAR 800-700 MB DEPICTED IN THE 06Z GFS AND HINTED AT BY THE ECMWF. SO...MENTION OF SLEET OVER THE SE WAS RETAINED. WITH THE STRONG DYNAMICS AND MOISTURE TRANSPORT...SNOWFALL AMOUNTS OF 10 INCHES OR MORE ARE EXPECTED OVER MUCH OF THE CWA. SO...WINTER STORM WATCH WAS POSTED FOR EXPECTED HAZARDS OF HEAVY SNOW AND STRONG WINDS WITH SIGNIFICANT BLOWING AND DRIFTING SNOW WITH LCL VERY LOW VSBYS. GFS/NAM AND THE NAM SHOW ERLY 950 WINDS AOA 50KT BY 00Z/FRI. GRADIENT SHOULD BE TIGHT ENOUGH FOR A DECENT PORTION OF THESE WINDS TO MIX TO THE SFC WITH GUSTS AOA 30KT EXPECTED IN FAVORED EXPOSED LOCATIONS TO EAST WINDS. FRI INTO FRI NIGHT...IF THE LOW PATH IS NEAR THE UKMET/GFS/CANADIAN VERIFIES...A VERY FAVORABLE SCENARIO FOR LAKE ENHANCED SNOWFALL INTO N CNTRL UPR MI WILL DEVELOP WITH STRONG ENE UPSLOPE FLOW AND ADDIITONAL HEAVY SNOW OVER THE HIGHER TERRAIN. SAT-TUE...CYCLONIC NRLY FLOW WITH 850 MB TEMPS NEAR -14C SHOULD KEEP LES OR LAKE ENHANCED SNOW GOING OVER THE AREA WHICH WILL TRANSISTION TO PURE LES AND DIMINISH BY SUN AS AN UPSTREAM SHRTWV APPROACHES FROM CNTRL CANADA AND HIGH PRES TEMPORARILY BUILDS IN. THE 12Z GFS AND 12Z ECMWF BRING A SHRTWV AND ARCTIC COLD FRONT THROUGH BY MON WITH ADDITIONAL LES POTENTIAL FOR NW FLOW FAVORED LOCATIONS. UNCERTAINTY...AS EXPECTED...IS HIGH BY TUE BUT MDLS SUGGEST THAT PATTERN WILL BE PROGRESSIVE ENOUGH FOR POSSIBILITY OF A CLIPPER OR WAA -SN DEVELOPING TUE. && .MQT WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH WED NIGHT THRU FRI AFTN MIZ009-012. WINTER STORM WATCH LATE WED NIGHT THRU FRI EVENING MIZ001>005-013-084. WINTER STORM WATCH THU MORNING THRU FRI EVENING MIZ006-014-085. GALE WARNING LAKE SUPERIOR. && $$ ROLFSON (UPDATE) AJ (SHORT TERM) JLB (LONG TERM)
AREA FORECAST DISCUSSION
NWS BINGHAMTON NY
1233 AM EST MON FEB 26 2007 .AVIATION /06Z-06Z/... PERSISTENT LIGHT SNOW WILL CONTINUE THROUGH THE MORNING HOURS. SOME MIXED PRECIPITATION IS EXPECTED NEAR AVP. EXPECT A CONTINUATION OF MVFR AND IFR CONDITIONS STRAIGHT THROUGH THE AFTERNOON, AS THE CYCLONE CAUSING THE SNOW IS BEING FOLLOWED UP A STRONG SHORT WAVE TO THE WEST. DJP && .PREV DISCUSSION... /ISSUED 957 PM EST SUN FEB 25 2007/ UPDATE... UPDATE TO ACCOUNT FOR CURRENT RADAR/OBSERVATION TRENDS WHICH SHOW STEADIEST SNOW MOVING NORTH AND EAST OF KBGM ATTM WITH MORE SHOWERY SNOW IN ITS WAKE. HAVE REMOVED MUCH OF THE MENTION OF SLEET...WITH NONE EXPECTED TO MAKE IT NORTH OF OUR NORTHERN PA BORDER COUNTIES. THIS IS IN GOOD AGREEMENT WITH CURRENT ACARS SOUNDINGS AS WELL AS NAM/RUC BUFKIT PROFILES. IN ADDITION...HAVE ADDED MENTION OF FZDZ...AS IN BETWEEN SHSN LATER TONIGHT...THE SATURATED LAYER SINKS SOMEWHAT TO LIE COMPLETELY WITHIN THE 0 - -10C ZONE...SUGGESTING FZDZ MAY PROVIDE A VERY LIGHT ICE COATING OVERNIGHT. SNOWFALL AMOUNTS SO FAR HAVE BEEN AROUND 1 INCH. IMPRESSIVE BANDING OVER THE PAST FEW HOURS YIELDED RIMED SNOW CRYSTALS HERE AT KBGM...SUGGESTING THAT MUCH OF THE LIFT IS BELOW THE BEST DENDRITIC GROWTH ZONE. THUS..EVEN WITH THE MODELS GIVING US PRETTY DECENT QPF OVERNIGHT...BELIEVE SNOW PRODUCTION WILL NOT BE PARTICULARLY EFFICIENT AND THEREFORE ACCUMS WILL SUFFER AS A RESULT. A GENERAL 1-3 LOOKS ON TRACK...WITH A SLIGHT CHANCE OF SOME 4 INCH AMOUNTS...ESPECIALLY OVER SOUTHEASTERN PORTIONS OF SULLIVAN/PIKE COUNTIES. HAVE DECIDED TO LEAVE THE ADVISORY AS IS...AS THE AREA IT COVERS HAS THE BEST SHOT OF SEEING SOME MIX...AND WILL ALSO BE THE CLOSEST TO THE DEVELOPING SFC LOW THAT WILL BE MOVING OFF THE EAST COAST OVERNIGHT. IF THAT LOW FAILS TO SEND APPRECIABLE MOISTURE TOWARDS THE SOUTHEASTERN PORTION OF THE CWA...ADVISORIES MAY NEED TO BE DROPPED. UPDATED CURRENT TEMPS/DEWPOINTS BASED ON LATEST TRENDS AS WELL. -JMA PREV DISCUSSION... /ISSUED 747 PM EST SUN FEB 25 2007/ UPDATE... UPDATE TO ACCOUNT FOR DECENT BAND OF LGT/MOD SNOW MOVING NORTHEAST THROUGH THE CWA ATTM. WILL UP POPS OVER THE NORTHEASTERN ZONES TO CATEGORICAL WITH ABOUT AN INCH OF SNOW OVERNIGHT. HAVE ALSO ELIMINATED THE CHC FOR IP OVER WESTERN ZONES THROUGH THE NIGHT AS ACARS SOUNDINGS ALONG WITH RUC SHORT TERM GUIDANCE SUGGESTS NO ABOVE FREEZING AIR IN THE COLUMN. AM THINKING THAT IP/ZR CHANCES OVER THE SOUTHEAST MAY BE A BIT OVERDONE AS WELL...BUT THE BEST CHC FOR A MIX REMAINS OVER THIS AREA. ALSO...AS THE PCP BECOMES MORE SHOWERY LATER...FZDZ IS POSSIBLE IN BETWEEN SHOWERS OF SN/IP...BUT NO MORE THAN A VERY LIGHT GLAZE IS EXPECTED. -JMA PREV DISCUSSION... /ISSUED 700 PM EST SUN FEB 25 2007/ AVIATION /260000Z - 270000Z/... FOR KSYR AND KRME...VFR WILL PERSIST THROUGH AT LEAST THE FIRST HALF OF TONIGHT. WE EXPECT LIGHT SNOW TO MOVE IN LATE TONIGHT...GENERALLY AFTER 04Z AT KSYR...AND POSSIBLY NOT UNTIL TOWARDS DAYBREAK AT KRME. ONCE SNOW STARTS...IT WILL CONTINUE MOST OF THE TIME...RIGHT THROUGH THE DAY MONDAY...WITH PREVALENT MVFR TO IFR CONDITIONS. ELSEWHERE IN CENTRAL NY/NORTHEAST PA (KELM...KITH...KBGM...AND KAVP)...IT WILL SNOW MUCH OF THE TIME...RIGHT THROUGH MONDAY EVENING. THE MOST PERSISTENT AND HEAVIEST SNOWS WILL OCCUR TONIGHT...WITH OCCASIONAL IFR/LIFR EXPECTED (UNDER 1 MILE VISIBILITY). THE SNOW SHOULD BE SOMEWHAT LIGHTER AND MORE SPORADIC DURING THE DAY MONDAY...BUT CEILINGS/VISIBILITIES WILL STILL LIKELY BE LOW ENOUGH FOR PERIODIC IFR. -MJ PREV DISCUSSION... /ISSUED 214 PM EST SUN FEB 25 2007/ SHORT TERM /TONIGHT THROUGH TUESDAY/... SLOW MOVG UPR LOW OVER THE GTLAKES WILL GRADUALLY SHEAR OUT OVER THE NXT 46-60 HRS. 2NDRY LOW DVLPS OVR THE MID ATLC CST TNGT, WITH A SURGE OF PCPN XPCTD TO WORK NWD INTO NE PA, WITH HEAVIEST PCPN SCRAPING OUR FAR SE ZONES. MDLS SUGGEST A WEAK SFC WAVE TRANSLATING EWD ACRS CNTRL NY ON MONDAY. LEADING EDGE OF PCPN HAS HAD A HARD TIME MOVG NEWD DUE TO LOW LVL DRY AIR, WITH A "SPLIT" IN THE MAIN PCPN AREA OVER WRN PA. HOWEVER, XPCT THIS AREA TO FILL IN LATER THIS AFTN AND EVNG. FAIRLY COMPLEX WX SCENARIO UNFOLDING FOR TNGT WITH MAIN CONCERNS PCPN TYPE AND AMTS ACRS THE CNTRL SRN TIER AND NE PA, AND ALSO THE NWD PROGRESSION OF THE PCPN. GFS CLEARLY SHOWS THE BEST POTNL FOR FZRA OVER THE CNTRL SRN TIER AND NE PA. LOCAL WRF MDL PROFILES MORE CLOSELY RESEMBLE THE NAM PROFILES, WHICH SUGGEST SNOW AND SOME SLEET...MAYBE SOME -FZRA ACRS PORTIONS OF NE PA. WE ARE LEANING TWDS THE COLDER SOLUTION, BUT EVNG CREW WILL HAVE TO MONITOR, AS FZRA WOULD REQUIRE THE ISSUANCE OF AN ADVISORY FOR THE CNTRL SRN TIER. SNOW ACCUMS ARE NOT XPCTD TO REACH ADVISORY LVLS ACRS THIS AREA. LATEST TRENDS ALSO INDICATE THE ADVISORY FOR NE PA MAY NOT PAN OUT WITH MAIN PCPN SHIELD ASSCD WITH MID ATLC 2NDRY LOW REMAINING TO OUR SE. FOR NOW WILL STICK WITH ADVISORY FOR 2-5 INCHES (BEST ACCUMS ACRS SRN SXNS OF THESE COUNTIES) AND MIX WITH SLEET, AND ADD SULLIVAN COUNTY TO THE ADVISORY. BEST POTNL FOR ADVISORY SNOW ACCUMS STILL APPEARS TO BE SOUTH OF A MSV-AVP LINE. FAR SRN LUZERNE AND PIKE COUNTIES MIGHT SEE A SLIGHTLY BETTER CHC FOR SOME -FZRA LATE TNGT. WE ALSO RAISED POPS FOR NRN ZONES (ONEIDA COUNTY) AS MDLS NOW IN AGREEMENT THAT NRN EDGE OF PCPN SHIELD WILL REACH THIS AREA. WE WENT WITH CAT POPS FOR MOST OF THE AREA TMRW, GIVEN THE SHEARED-OUT VORT LOBE AND WEAK SFC WAVE/TROF. PCPN TYPE LOOKS TO BE SNOW, BUT SOME PROFILES FOR NE PA INDICATES POTNL FOR -FZDZ IN THE MRNG. CONTINUED UNSETTLED CONDITIONS INTO TUES WITH PDS OF LGT SNOW OR SNOW SHOWERS, WITH ACCUMS OF 1-2 INCHES PSBL IN ANY 12-HR PD, PRIMARILY ACRS UPSTATE NY. ACTIVITY NOT XPCTD TO BE AS WDSPRD ON TUES. LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... NW FLOW BEHIND SYSTEM ON TUESDAY NIGHT COULD SPARK SOME LE SNOW SHOWERS OVER PARTS OF THE AREA. HOWEVER MOISTURE DEPTH WILL BE LACKING AND NOT LOOKING FOR MUCH IN THE WAY OF COVERAGE/INTENSITY. HIGHLY AMPLIFIED PATTERN WILL BE IN PLACE THROUGH THE REMAINDER OF THE WEEK INTO THE WEEKEND. UPPER LOW DIVES INTO MIDWEST ON THURSDAY...BRINGING H5 RIDGE AND DRYING CONDS TO CWA THRU THE DAY. YET ANOTHER SFC SYSTEM DEVELOPS WITH SFC WARM FRONT AND WAA GIVING QUICK SHOT OF PCPN LATE IN THE WEEK. ECMWF ADVERTISES THIS SYSTEM GOING WELL TO OUR WEST AS WAS THE CASE FOR THE PREVIOUS SYSTEM. GFS ALSO SHOWS THIS SOLN WITH SECONDARY LOW DEVELOPMENT ALONG THE COAST. HAVE FOLLOWED ECMWF/HPC GUIDANCE THIS PERIOD...ALTHOUGH HAVE LOWERED TEMPS A TAD EACH DAY GIVEN PRIOR HISTORY TO THESE SYSTEMS TO HAVE A TOUCH COLDER AIR THAN EXPECTED. HAVE OPTED FOR A SLOWER/MORE AMPLIFIED SCENARIO IN EXTENDED PERIOD...WITH UL LOW REMAINING OVER CENTER OF NATION UNTIL NEXT KICKER DROPS DOWN INTO PACIFIC NORTHWEST. AVIATION /18Z-18Z/... HIGH OVC DECK ARND 20KFT WILL GAVE WAY TO LOWERING CIGS THIS AFTERNOON AND EVENING AS STORM SYSTEM APPROACHES FROM THE WEST. FOUR SRN TERMINALS TO SEE MVFR CIGS MOVING IN BTWN 21Z-23Z WITH CEILINGS EXPECTED TO BE 2500FT. BY 00Z KELM/KAVP/KBGM WILL SEE 2SM VSBYS IN LIGHT SNOW...SPREADING TO KITH BY 02Z. VISIBILITIES WILL OCNLY BE REDUCED TO BLO 1SM DURING THE OVERNIGHT PERIOD. AT KELM...COULD SEE SNOW MIXING WITH -FZRA BTWN 04Z-08Z AND WITH SLEET AT KAVP BTWN 07Z-11Z. FURTHER NORTH AT KSYR/KRME...SNOW EXPECTED TO MOVE IN AFTER MIDNIGHT. LEAST LIKELY SITE WILL BE KRME WITH VSBYS RESTRICTED TO 4SM ENTIRE TAF PERIOD. ALL SITES WITH EXCEPTION OF KRME WILL SEE CIGS DROP BLO 1KFT AS LOW PRESSURE CTR APPROACHES. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR NYZ062. PA...WINTER WEATHER ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR PAZ044-047-048-072. && $$ AVIATION...DJP
AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NWS SIOUX FALLS SD
845 PM CST TUE FEB 27 2007 .DISCUSSION... PLENTY OF ECHOES HAVE BEEN DEVELOPING ON REGIONAL RADARS OVER THE PAST COUPLE OF HOURS WITH ADVANCE OF MID LEVEL FRONTAL ZONE. HOWEVER NOT A LOT OF THIS PRECIP BEING REALIZED AT THE SURFACE QUITE YET... WITH KABR/KOAX RAOBS AND RECENT TAMDAR SOUNDINGS OUT OF KSUX ALL SHOWING DEEP DRY LAYER BETWEEN 600-875MB. QUITE A BIT OF MID LEVEL LIFT MOVING INTO THE CWA...MAINLY AFTER 06Z. INITIAL LIFT WILL HAVE TO WORK TOWARD SATURATION...BUT QUICK RAMP-UP/EXPANSION OF POPS IN 06Z-12Z TIMEFRAME STILL LOOKS VERY REASONABLE. POTENTIAL FOR MIXED PRECIP LOOKS LIKE THE CORRECT CHOICE FOR MISSOURI RIVER AREA AS WELL...WITH KSUX TAMDAR SOUNDINGS SHOWING WARM LAYER AT ZERO TO +1C AT 850MB. 00Z NAM LOOKS TO HAVE INITIALIZED THIS AREA PRETTY WELL... BUT NOT QUITE COLD ENOUGH ON THE BACK SIDE WHERE 00HR 850MB TEMPS AT KUNR/KLBF ARE 2-3C TOO WARM. WILL TAKE A LITTLE CLOSER LOOK BEFORE MAKING ANY CHANGES...BUT MAY NEED TO INTRODUCE BRIEF PERIOD OF MIXED PRECIP INTO SOUTHWEST COUNTIES FOR THE LATE NIGHT HOURS AS WELL. TWEAKED HOURLY TEMPS EARLIER THIS EVENING...ESPECIALLY IN NORTHEAST AREAS WHERE THEY DID NOT WARM UP QUITE AS MUCH AS EXPECTED IN THE AFTERNOON. TEMPS SHOULD REBOUND A LITTLE OVERNIGHT AS WINDS INCREASE THOUGH...AND GOING FORECAST HAS THIS IDEA WELL HANDLED. NO UPDATES TO ZFP NEEDED AT THIS TIME...THOUGH AS MENTIONED ABOVE...MAY NEED TO BRIEFLY MENTION SOME SLEET IN FAR SOUTHWEST CWA AFTER 06Z. UPDATED GRIDS/PFM HAVE BEEN SENT. && .AVIATION... VFR CONDITIONS AT KHON/KFSD/KSUX AREAS WILL DETERIORATE QUICKLY BETWEEN 06Z-12Z AS UPPER LEVEL LIFT INCREASES AND HELPS SATURATE ATMOSPHERE BENEATH QUICK MOVING MID LEVEL FRONT. PERIOD OF MODERATE TO BRIEFLY HEAVY SNOW POSSIBLE AT KHON/KFSD AFTER 11Z...WITH VSBYS ARND 1/2SM LKLY AT KHON 11Z-14Z...AND KFSD FROM 12Z-16Z. WARMER AIR ALFT SHUD BE LIMITED TO AREAS NEAR THE MISSOURI RIVER...INCLDUING ARND KSUX AND TWB302...WITH ICING CONDITIONS MOST LIKELY FROM 11Z-17Z. && .PREV DISCUSSION... APOLOGIES FOR THE VERY LONG HEADLINE CODE BELOW...ONE OF THE HAZARDS OF DEALING WITH TWO STORM EVENTS IN THE SHORTER TERM. FOR TONIGHT AND WED MORNING...AM ANTICIPATING SOME STEADY TO SLOWLY RISING TEMPS AFTER EVENING OR MIDNIGHT AS THE SE WINDS INCREASE. WE ARE STILL ON TARGET WITH A TON OF WAA MOVG INTO THE FA LATER TONIGHT AND WED ASSOCIATED WITH A S/W. A NW TO SE BAND OF SNOW WL DEVELOP ALONG A MID LVL FRONTOGENESIS BAND ASSOCIATED WITH THE MID LVL FRONT. ONE CAN ALREADY SEE ECHOES DEVELOPING IN WRN SD...WITH REDUCED VISIBILITIES AT PLACES SUCH AS RAPID CITY AND CUSTER. THIS BAND IS BEGINNING TO TIE INTO SOME LIGHT ECHOES IN NORTH CENTRAL NEB... HOWEVER THE LOW LVLS ARE INTIALLY DRY IN OUR CWFA. IN ADDITION...WE ARE UNSTABLE TONIGHT AND WED MORNING WITH THIS WAVE. ABOVE THE MAX FRONTOGENESIS AREA IS QUITE AN UNSTABLE AREA OF NEG EPV*. SOME LTG IS NOTED ATTM IN ERN WY. SO THOUGHTS ARE...THAT THE SNOW BAND COULD POUND PRETTY GOOD AS IT LIFTS NEWD ACROSS THE FA...ESP SINCE WE DO HAVE SOME DENDRITICITY TO WORK WITH. NAM THERMAL PROFILES DO SHOW A MIX OF PCPN IN THE FAR SRN CWFA LATE TONIGHT AND WED...EVEN AFTER SUBTRACTING OFF 1 TO 2 DEGS CELSIUS OFF OF THE USUALLY TOO WARM NAM WARM PROFILE. THEREFORE ISSUED A WINTER WX ADVY FOR MIXED PCPN FM KYKN TO KSLB. SNOW ADVYS OR WINTER STORM WARNINGS ARE WARRANTED NORTH OF THERE FOR MUCH OF THE REST OF THE FA FOR THE BAND OF SNOW. LEFT THE SW CWFA FREE OF HEADLINES AS FOR NOW...AS IT LOOKS LIKE THE DYNAMICS WL LIFT TOO FAR NEWD TOO FAST WED MORNING...LEAVING THAT AREA DRY BY AFTERNOON. BY WED AFTERNOON...NOT A HUGE REBOUND IN TEMPS IS EXPECTED DUE TO LOW CLOUD COVER HANGING AROUND. LIGHT SNOW WL STILL BE LIKELY IN OUR NE SECTOR WHERE MSTR REMAINS THE DEEPEST. HOWEVER MOVG SW OF THERE... DRY AIR BEGINS TO POUR INTO THE MID LVLS. SO...IF ANY PCPN HAPPENS WED AFTERNOON IN AREAS W OF SW MN...IT SHOULD BE DRIZZLE OR FREEZING DRIZZLE. BUT WOULD BE EXTREMELY LIGHT. NEXT VERY STRONG SYSTEM THEN LIFTS NEWD ON THU INTO THE ERN PLAINS. OUR FAR SERN CWFA IN NW IA GETS SCRAPED BY SOME LOW TO MID LVL FRONTOGENESIS WED NIGHT. HOWEVER...AM NOT BUYING THE STRONG QPF IN THAT AREA WED NIGHT PER THE GFS...AS THE GFS DEVELOPS A CONVECTIVE LOOKING S/W NEAR SPENCER IA. MID LVLS PER BOTH MODELS ARE STILL RATHER DRY FOR MUCH OF THE FA...SO BELIEVE ONLY VERY LIGHT PCPN IS WARRANTED OVER OUR NE HALF. THEN AS MENTIONED...THE STRONG UPPER WAVE THEN LIFTS NEWD FM THE CENTRAL PLAINS INTO ERN PLAINS WHERE IT BOMBS. VERY WINDY CONDS WILL PREVAIL...ESP BY THU NIGHT AND FRIDAY WITH SOME POSSIBLE HEAVY SNOW IN PARTS OF OUR ERN FA BEHIND THE UPPER LOW. TROWALING IS STILL EVIDENT ON FRI AND FRI NIGHT IN ERN SD KEEPING THINGS STIRRED UP IN THIS AREA. WE MAY HAVE TO EXTEND THE WINTER STORM WATCH WWD FM ABOUT SIOUX FALLS TO BROOKINGS ON FUTURE SHIFTS BECAUSE THE WIND IS SO STRONG. BUT WERE STILL EXPECTING THE HEAVIEST SNOW AMOUNTS OF 6 TO 10 INCHES IN OUR FAR ERN CWFA ON THURSDAY...POSSIBLY THU EVENING WHEN THE MID TO UPPER LOW IN IN NRN IA. IN THE EXTENDED...BRISK NORTHWEST FLOW WILL CONTINUE INTO SATURDAY WITH AROUND 30 KNOTS OF FLOW AT 925 MB GRADUALLY DECREASING THROUGHOUT THE DAY. THERE IS THE POTENTIAL FOR A FEW FLURRIES IN THE EAST EARLY SATURDAY MORNING...BUT AS THE MID LEVELS CONTINUE TO DRY OUT WOULD NOT EXPECT FLURRIES TO LAST BEYOND MIDDAY. NOT CONFIDENT ENOUGH TO ADD TO FORECAST AT THIS POINT...BUT IS SOMETHING TO KEEP AN EYE ON. EXPECT ATMOSPHERE TO CONTINUE TO DRY OUT THROUGHOUT THE DAY ON SATURDAY...AND CLOUD SHIELD WILL GRADUALLY SHIFT EAST WITH DEPARTING UPPER LEVEL LOW. BRIEF WARMING TREND WILL ENSUE SATURDAY INTO SUNDAY...THOUGH HAVE CONTINUED CONSERVATIVE HIGHS DESPITE 925 MB RISING TO NEAR 0 C. WARMING TREND DOESN/T LAST TOO LONG THOUGH...AS ARCTIC PUSH WORKS INTO UPPER MIDWEST ON MONDAY. BELOW NORMAL TEMPERATURES WILL CONTINUE INTO TUESDAY...THOUGH HIGHS ON TUESDAY LOOK TO WARM SOME OVER MONDAY/S COOL READINGS. && .FSD WATCHES/WARNINGS/ADVISORIES... IA...SNOW ADVISORY FROM 2 AM TO 12 PM CST WEDNESDAY FOR IAZ001-012. WINTER WEATHER ADVISORY FROM 2 AM TO 12 PM CST WEDNESDAY FOR IAZ020-031. SNOW ADVISORY FROM 6 AM TO 6 PM CST WEDNESDAY FOR IAZ002-003-013-014. WINTER STORM WATCH FROM THURSDAY MORNING THROUGH FRIDAY AFTERNOON FOR IAZ001>003-012>014-021-022-032. WINTER WEATHER ADVISORY FROM 6 AM TO 4 PM CST WEDNESDAY FOR IAZ021-022-032. MN...SNOW ADVISORY FROM 2 AM TO 12 PM CST WEDNESDAY FOR MNZ098. WINTER STORM WARNING FROM 6 AM TO 6 PM CST WEDNESDAY FOR MNZ071- 072-080-081-089-090-097. WINTER STORM WATCH FROM THURSDAY MORNING THROUGH FRIDAY AFTERNOON FOR MNZ071-072-080-081-089-090-097-098. NE...WINTER WEATHER ADVISORY FROM 2 AM TO 12 PM CST WEDNESDAY FOR NEZ013-014. SD...SNOW ADVISORY FROM 2 AM TO 12 PM CST WEDNESDAY FOR SDZ052-053- 059>062-066-067. WINTER WEATHER ADVISORY FROM 2 AM TO 12 PM CST WEDNESDAY FOR SDZ065-068>071. WINTER STORM WARNING FROM 6 AM TO 6 PM CST WEDNESDAY FOR SDZ040- 056. WINTER STORM WARNING FROM 2 AM TO 12 PM CST WEDNESDAY FOR SDZ038-039-054-055. && $$ JH
AREA FORECAST DISCUSSION
NWS MORRISTOWN TN
420 AM EST MON FEB 26 2007 .SHORT TERM (TODAY AND TONIGHT)...MOISTURE TRAPPED BELOW A MIDLEVEL INVERSION IS RESULTING IN A STRATOCU DECK ACROSS THE AREA THIS MORNING. ACARS SOUNDINGS INDICATE THAT THIS CLOUD DECK IS NOT VERY THICK...ABOUT 1000-1500 FEET. THE MODELS DO SHOW SOME MIDLEVEL DRY ADVECTION WORKING ITS WAY INTO THE AREA AFTER SUNRISE...SO EXPECT THAT THIS CLOUD DECK WILL DISSIPATE AROUND THAT TIME. CONSIDERABLE HIGH CLOUDINESS OVER THE CENTRAL US ASSOCIATED WITH THE UPPER JET AND SOME CHANNELED VORTICITY WILL MOVE INTO THE AREA BY THE AFTERNOON...GIVING MOSTLY CLOUDY SKIES. THE VORT AXIS CROSSES THE NORTHERN PORTION OF THE AREA TONIGHT...BUT PRODUCES NO LIFT...AND MOISTURE IS LACKING OUTSIDE OF A THIN MIDLEVEL LAYER. WILL REMOVE THE SLIGHT CHANCE POPS FROM THE PREVIOUS FORECAST. .LONG TERM (TUESDAY THROUGH SUNDAY)...HIGH PRESSURE BUILDS IN ON TUESDAY...BRINGING DRY WEATHER FOR TUESDAY AND WEDNESDAY. A FRONT APPROACHES ON LATE WEDNESDAY NIGHT...WILL KEEP SLIGHT CHANCE POPS FOR OUR WESTERN ZONES FOR LATE WEDNESDAY NIGHT. BEST CHANCES SHOULD HOLD OFF UNTIL THURSDAY WHEN BETTER MOISTURE AND LIFT PUSHES IN WITH IT. 50-6KT LOW LEVEL JET IS ALSO EXPECTED ON THURSDAY ALONG WITH SOME WEAK INSTABILITY...WILL ADD THUNDER TO THE FORECAST FOR THURSDAY AND THURSDAY EVENING. FRONT LINGERS INTO THURSDAY NIGHT... WILL KEEP CHANCE POPS FOR THURSDAY NIGHT. SHOULD BE WARM ENOUGH FOR ALL LIQUID PRECIPITATION. THE FRONT IS EAST OF THE AREA ON FRIDAY WITH MOISTURE DECREASING BEHIND IT. WITH UPPER LOW NEARBY...WILL KEEP CHANCE POPS IN FOR FRIDAY WITH BEST CHANCES IN THE NORTH. UPPER LOW TRACKS NORTH ON FRIDAY NIGHT...WILL KEEP FRIDAY NIGHT AND SATURDAY DRY. ANOTHER DISTURBANCE MOVES IN ON SATURDAY NIGHT AND SUNDAY. WITH STILL SOME UNCERTAINTY ON TIMING...WILL KEEP SATURDAY NIGHT AND SUNDAY DRY FOR NOW. && .PRELIMINARY POINT TEMPS/POPS... CHATTANOOGA AIRPORT, TN 61 37 63 35 65 / 0 0 0 0 10 KNOXVILLE MCGHEE TYSON AIRPORT, TN 57 35 60 33 62 / 0 10 0 0 10 OAK RIDGE, TN 56 34 58 32 61 / 0 10 0 0 10 TRI CITIES AIRPORT, TN 51 32 57 30 59 / 0 10 0 0 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DGS/GH
AREA FORECAST DISCUSSION
NWS SEATTLE WA
910 PM PST SUN FEB 25 2007 .SYNOPSIS...A COLD UPPER LEVEL TROUGH WILL REMAIN OFF THE COAST THROUGH MIDWEEK...BRINGING COOL AND SHOWERY WEATHER TO THE REGION. TEMPERATURES MAY MODERATE TOWARD THE END OF THE WEEK BUT THE THREAT OF RAIN WILL CONTINUE. && .SHORT TERM...DE-JA-VU. THINGS LOOK VERY SIMILAR TO WHEN I WAS WRITING THE DISCUSSION 24 HOURS AGO. SHOWERS ROLLING NORTH UP THROUGH WESTERN WASHINGTON WITH ENHANCEMENT IN THE CLOUD FIELD ON THE IR IMAGERY OFFSHORE...THROUGH SOUTHWEST WASHINGTON AND INTO OREGON. THIS FEATURE ROTATING NORTHWARD WHICH WILL HOLD THE SHOWERS OVER THE REGION THROUGH A GOOD CHUNK OF THE NIGHT. SHOWER WORDING PRETTY MUCH BLANKETED ACROSS THE FORECAST FOR TONIGHT SO WE ARE IN GOOD SHAPE WITH THAT. RATHER WARM AT THE MOMENT WITH A FREEZING LEVEL UP AROUND 3300 FEET OVER THE SOUND ACCORDING TO ACARS AND AROUND 2900 FEET OVER KUIL...THEREFORE NEARLY ALL THE PRECIP IS EXPECTED TO BE RAIN FOR THE LOWLANDS. BUT WITH SOME COOLING IN THE LOW LEVELS OVERNIGHT...COULD SEE A BIT OF WET SNOW MIXED IN THE HEAVIEST SHOWERS BUT NOT ENOUGH TO BRING ABOUT ANY ACCUMULATION. HOWEVER THAT MAY NOT BE THE CASE MONDAY NIGHT AND TUESDAY NIGHT AS SHOWER ACTIVITY WILL BE CONTINUING AND THE AIR MASS WILL BE COOLER OVERALL. THE SNOW WORD IS ALREADY SPRINKLED THROUGHOUT THE FORECAST THOSE TIME PERIODS SO THAT ALSO LOOKS GOOD. NOT MUCH ELSE TO DEAL WITH AT THE MOMENT. CERNIGLIA .LONG TERM...FROM PREVIOUS DISCUSSION...A DRYING TREND NOTED IN 18Z RUN OF GFS AFTER LAST TROUGH EXITS REGION WEDNESDAY NIGHT OR SO. THIS COULD MEAN A RELATIVELY DRY THURSDAY AND THURSDAY NIGHT IN COOL DRY NW FLOW. FORECAST STILL HAS HIGH POPS AS CONFIDENCE LOW. RAIN DEVELOPS FRIDAY AND CONTINUES OFF AND ON THROUGH SATURDAY NIGHT WITH SHOWERS SUNDAY. SHOULD BE WARMER THIS WEEKEND WITH TEMPS GETTING INTO THE LOW 50S...WHICH IS AROUND 10 DEGREES WARMER THAN THE FIRST PART OF THE WEEK. BURKE && .AVIATION...A WEAKENING AREA OF LOW PRESSURE REMAINS TO THE WEST OF VANCOUVER ISLAND. BANDS OF MOISTURE WILL CONTINUE TO MOVE AROUND THE LOW INTO OREGON...THEN NORTHWARD INTO WESTERN WASHINGTON THROUGH MONDAY AFTERNOON. MULTIPLE CLOUD LAYERS OVER WESTERN WASHINGTON WITH CONDITIONS REMAINING FAIRLY CONSTANT...CEILINGS BETWEEN 3500 TO 5000 FEET LOWERING TO NEAR 2000 FEET WITH THE SHOWER ACTIVITY. .KSEA...MOSTLY BROKEN LAYER 3500 TO 4500 FEET WITH ANOTHER LAYER 6000 TO 8000 FEET. CEILINGS LOWERING TO NEAR 2000 FEET WITH HEAVIER SHOWERS THROUGH MONDAY AFTERNOON. SOUTHERLY WINDS 6 TO 10 KNOTS THROUGH MONDAY AFTERNOON. FELTON $$ .SEW WATCHES/WARNINGS/ADVISORIES... .SMALL CRAFT ADVISORY COAST. .SMALL CRAFT ADVISORY FOR ROUGH BAR CONDITIONS GRAYS HARBOR BAR. $$
AREA FORECAST DISCUSSION
NWS LA CROSSE WI
315 PM CST TUE FEB 27 2007 .SHORT TERM...THROUGH FRIDAY NIGHT PRIMARY FORECAST CONCERN REMAINS FOCUSED ON POTENTIAL FOR ANOTHER HIGH IMPACT WINTER STORM TO AFFECT THE AREA WEDNESDAY THROUGH FRIDAY. MAIN ISSUES WITH THIS STORM WILL BE MUCH LIKE THOSE OF THE 23-25FEB07 WEEKEND STORM. THEREFORE...FOCUS WAS CENTERED ON POTENTIAL FOR SIGNIFICANT SNOW AND ICE ACCUMULATIONS...ALONG WITH STRONG WINDS. MEDIA PARTNERS...EMERGENCY MANAGERS AND AVIATION INTERESTS ARE ADVISED TO ESPECIALLY KEEP ABREAST OF THE LATEST INFORMATION VIA HAZARDOUS WEATHER OUTLOOKS AND WINTER WEATHER STATEMENTS. THIS AFTERNOON...SURFACE ANALYSIS INDICATED LINGERING TROUGH OF LOW PRESSURE EXTENDING FROM LOWER MICHIGAN WESTWARD ACROSS CENTRAL PART OF WI AND INTO NORTHERN MN. WATER VAPOR IMAGERY INDICATED VIGOROUS MID LEVEL CIRCULATION OVER THE PACIFIC NORTHWEST. UPPER AIR AND ACARS DATA INDICATED STRONG 300MB JET STREAM OF 120-150KT ROTATING AROUND BASE OF TROUGH. SURFACE CYCLOGENESIS EVIDENT OVER INTERMOUNTAIN WEST AND CONFIRMED BY COMMA SHAPE CLOUD IN INFRARED SATELLITE IMAGERY. 12Z 27FEB07 SURFACE AND UPPER LEVEL FEATURES WERE INITIALIZED WELL. CLUSTER OF GFS ENSEMBLE MEMBERS INDICATED SURFACE LOW SHOULD TRACK FROM OK/TX PANHANDLE AREA INTO MID MISSISSIPPI VALLEY TO NORTHERN LAKE MICHIGAN. LATEST OPERATIONAL ECMWF AND NAM/WRF SUPPORTED A TRACK FURTHER NORTHWEST THAN GFS ENSEMBLES...WHICH STILL LENDS SOME UNCERTAINTY IN EXACT DETAILS...ESPECIALLY WITH RESPECT TO PRECIPITATION TYPE. REGARDLESS OF WHICH LOW TRACK VERIFIES...CONFIDENCE WAS HIGH ENOUGH TO UPGRADE TO WINTER STORM WARNING IN NORTHERN AND WESTERN MOST SECTIONS OF THE FORECAST AREA. WINTER STORM WATCH WAS EXPANDED A BIT FURTHER INTO CENTRAL WI...AS WELL AS PARTS OF NORTHEAST IOWA. IN SPITE OF MODEL DIFFERENCES WITH RESPECT TO TRACK OF SYSTEM... HIGHEST PROBABILITIES OF SNOW RESIDE ACROSS NORTHERN AND WESTERN MOST SECTIONS OF THE FORECAST AREA. ELSEWHERE...A WINTRY MIX APPEARS PROBABLE...WITH EVEN ALL RAIN FOR A TIME IN SOUTHERN AND EASTERN MOST PARTS OF THE FORECAST AREA. OVERALL...FORECAST CONFIDENCE REMAINS HIGH FOR POTENTIALLY SIGNIFICANT WINTER STORM TO IMPACT THE FORECAST AREA WEDNESDAY THROUGH FRIDAY. WEDNESDAY INTO WEDNESDAY NIGHT...FIRST OF TWO ROUNDS OF PRECIPITATION EXPECTED. MODELS CONTINUE TO INDICATE AN UPPER LEVEL WAVE OVER THE DAKOTAS SHOULD CUT OFF...AS MORE ENERGY UPSTREAM IN THE BASE OF THE UPPER LEVEL TROUGH EJECTS INTO THE CENTRAL PLAINS. RESULT SHOULD BE A BROAD AND EXPANDING SHIELD OF WARM AIR ADVECTION PRECIPITATION ADVANCING ACROSS THE FORECAST AREA. THIS SHOULD BE FUELED BY STRONG 850MB JET OF 50KTS...WHICH BRINGS 3-4G/KG SPECIFIC HUMIDITY VALUES NORTHWARD. ISENTROPIC LIFT IN THE 280K-290K LAYER SUPPORTS BURSTS OF HEAVIER PRECIPITATION...ESPECIALLY WITH POTENTIAL FOR CONVECTION TO ENHANCE PRECIPITATION RATES. EXACT DETAILS OF LOW LEVEL TEMPERATURE STRUCTURE AND THUS PRECIPITATION TYPE STILL A BIT OF A QUESTION MARK BASED ON VARIABILITY IN MODELS TRACK OF SURFACE LOW. GFS STILL SUPPORTS MORE SNOW...WHILE NAM/WRF SUGGESTS MORE FREEZING RAIN/SLEET POTENTIAL. AT THIS TIME...INCORPORATED A COMPROMISE APPROACH WITH MIXED PRECIPITATION ACROSS ABOUT THE SOUTH HALF OF THE FORECAST AREA WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT. IN ADDITION...THERE WAS ENOUGH CONFIDENCE TO DEPICT ALL RAIN IN SOUTHERN MOST SECTIONS WEDNESDAY NIGHT...WITH WARM AIR NOSING IN AHEAD OF APPROACHING LOW. THURSDAY INTO THURSDAY NIGHT...ROUND TWO OF THIS WINTER WEATHER EVENT SHOULD MANIFEST ITSELF...AS MAIN SYNOPTIC SCALE SYSTEM BRINGS POTENTIALLY HEAVY PRECIPITATION. TROWAL SIGNATURE REMAINS IMPRESSIVE...AS DOES AN INCREDIBLY CONSISTENT AND STRONG UPPER LEVEL DIVERGENCE SIGNAL ASSOCIATED WITH COUPLED 300MB JET. DEEP LAYERED Q-G CONVERGENCE ALSO SUGGESTS DEEP LAYERED LARGE SCALE ASCENT...WHICH SHOULD SUPPORT A BURST OF HEAVY PRECIPITATION. CATEGORICAL VALUES OF PRECIPITATION PROBABILITY MAINTAINED IN CURRENT DATA BASE ON THURSDAY AND EXPANDED INTO THURSDAY NIGHT. CONFIDENCE WAS FAIRLY HIGH THAT SNOW SHOULD BE PRIMARY PRECIPITATION TYPE ACROSS NORTH AND WEST SECTIONS OF THE FORECAST AREA ON THURSDAY. CONFIDENCE NOT QUITE AS HIGH AS ONE WOULD LIKE IN EAST AND SOUTH SECTIONS OF THE FORECAST AREA. THEREFORE...MAINTAINED A RAIN OR SNOW SCENARIO ACROSS PARTS OF CENTRAL AND SOUTHWEST WI. AS COLDER AIR FILTERS IN BEHIND DEPARTING STORM THURSDAY NIGHT...PRECIPITATION SHOULD CHANGE TO ALL SNOW FAIRLY QUICKLY. FORECAST CONFIDENCE WAS FAIRLY HIGH THAT STRONG SURFACE WINDS SHOULD ACCOMPANY STORM SYSTEM THURSDAY INTO FRIDAY. IN FACT...MODEL PROJECTION OF DEEP SURFACE LOW PRESSURE SUGGESTS WIND GUSTS OF 40 TO 45 MPH SHOULD OCCUR...ESPECIALLY IN THE WIND PRONE AREAS OF SOUTHEAST MINNESOTA...NORTHEAST IOWA...AND THE RIDGETOPS OF SOUTHWEST WI. INCORPORATED THESE WIND GUSTS INTO CURRENT DATA BASE. THESE WIND SPEEDS COULD HAVE SIGNIFICANT IMPACTS...ESPECIALLY IN NORTH AND WEST SECTIONS OF THE FORECAST AREA WHERE HEAVY SNOWFALL POTENTIAL EXISTS. .LONG TERM...SATURDAY THROUGH TUESDAY DUE TO POTENTIAL FOR ANOTHER HIGH IMPACT WINTER WEATHER EVENT IN THE SHORT TERM...DAYS 6-7...WERE GIVEN A LOW PRIORITY. HOWEVER... CURSORY LOOK AT MEDIUM RANGE MODELS INDICATED SOME DIFFERENCES BETWEEN ECMWF AND GFS...WHICH COULD AFFECT SENSIBLE WEATHER... SPECIFICALLY EARLY NEXT WEEK. BESIDES CHANCE OF SOME LIGHT SNOW LINGERING ON SATURDAY IN AFTERMATH OF DEPARTING STORM...GFS INDICATED ANOTHER CHANCE OF SNOW ON MONDAY INTO MONDAY NIGHT ASSOCIATED WITH COLD FRONT PASSAGE. ON THE OTHER HAND...ECMWF HAD SURFACE RIDGE BUILDING IN. MODEL DIFFERENCES LOWER FORECAST CONFIDENCE...THUS FOLLOWED HPC GUIDANCE AND MAINTAINED DRY WEATHER AS IN CURRENT DATA BASE SUNDAY THROUGH TUESDAY. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY AFTERNOON FOR WIZ041-WIZ042-WIZ043-WIZ044. WINTER STORM WARNING FROM 6 PM WEDNESDAY TO 6 PM CST FRIDAY FOR WIZ017-WIZ029-WIZ032-WIZ033-WIZ034. MN...WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY AFTERNOON FOR MNZ088-MNZ095-MNZ096. WINTER STORM WARNING FROM 6 PM WEDNESDAY TO 6 PM CST FRIDAY FOR MNZ079-MNZ086-MNZ087-MNZ094. IA...WINTER STORM WATCH FROM WEDNESDAY EVENING THROUGH FRIDAY AFTERNOON FOR IAZ008-IAZ009-IAZ018-IAZ019. && $$ THOMPSON

AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
420 AM CST WED FEB 28 2007 .DISCUSSION... 420 AM CST POWERFUL JET MAX OF 160KTS PER AIRCRAFT REPORTS CROSSING NORTHERN BAJA AT BASE OF WESTERN NOAM UPPER TROF. SATELITE SHOWS MULTIPLE CIRCULATIONS IN THE TROF. ONE LIFTING NORTHWARD ACROSS THE NORTHERN HI PLAINS WITH A TROF AXIS EXTENDING SOUTHEASTWARD ALL THE WAY TO THE LOWER MO VALLEY WHERE STRONG WAA HAS REGENTLY GENERATED ELEVATED TSRA. THE WAA PATTERN AND ASSOCIATED UVV WILL LIFT NORTHWARD INTO THE MID MS VALLEY BY THIS EVE AS THE JET MAX CROSSES THE SOUTHERN ROCKIES AND TURNS NORTHEASTWARD ACROSS THE SOUTHERN PLAINS. MODELS SHOW H8 WARMFRONT LIFTING INTO SOUTHERN WI AND LOWER MI BY 06Z AND EXPECT INITIAL ROUND OF PRECIP TO CONTINUE TO MOVE NORTHWARD INTO THE UPPER MIDWEST AND GREAT LAKES. LOWER LEVELS REMAIN RELATIVELY DRY AS THIS PRECIP AREA MOVES IN DURING THE LATER AFTERNOON AS H8 DEW POINT DEPRESSIONS WERE 20 TO 30 DEG C ACROSS THE LOWER MS VALLEY LAST EVE. 00Z RAOBS DID SHOW MARGINAL MID LEVEL MOISTURE OVER THE OZARKS AHEAD OF THE LEAD SHORT WAVE TROF WHILE LOWER LEVELS WERE DRY EXCEPT FOR SHALLOW MOISTURE ALONG THE WESTERN GULF COAST. THIS MOISTURE HAS SPREAD RAPIDLY INTO THE SOUTHERN PLAINS WHERE SURFACE DEW POINTS APPROACHING 60F AS SOUTHERLY LOW LEVEL WINDS CONTINUE TO INCREASE AHEAD OF THE RAPIDLY DEVELOPING LEE SIDE LOW BUT THIS LOWER LEVEL MOISTURE DOES NOT REACH THE MID MS VALLEY UNTIL THIS EVE. AFTER THE INITIAL SHOT OF WAA PRECIP EXPECT A BREAK UNTIL INGREDENTS COME TOGETHER OVERNIGHT. THIS INCLUDES GULF MOISTURE SPREADING INTO CENTRAL IL...DIFLUENT UPPER FLOW AS TROF BECOMES NEGATIVELY TILTED AND DIVERGENCE ALOFT AT LEFT EXIT OF STRONG JET. STEEP MID LEVEL LAPSE RATES AND STRONG DYNAMICS WILL RESULT IN CONVECTIVE RAIN BREAKING OUT AND SPREADING ACROSS THE MID MS VALLEY. PRECIPITABLE WATER VALUES CLIMB TO AROUND 1 INCH AND MODERATE TO HEAVY RAINFALL POTENTIAL DUE TO EXPECTED CONVECTIVE NATURE AND FLOOD WATCH WILL BE CONTINUED GIVEN ALREADY SOME FLOODING PROBLEMS AND MOISTURE CONTENT OF SNOWPACK. UPPER LOW LINGERING OVER THE CANADIAN MARITIMES SLOWS THE PROGRESS OF THIS STORM AND IT BECOMES STACKED DURING THU AS IT LIFTS INTO IA. WINDS WILL GRADUALLY DIE DOWN AS LOW STARTS GRADUAL FILLING. DRY SLOT PUNCHES NORTHWARD DURING THU WITH OCCLUDED FRONT SWEEPING EAST AND NORTHEAST THRU THE FA. THIS WILL CURTAIL RAIN BUT WITH COLD AIR WRAPPED INTO SYSTEM AND IT/S SLOW MOVEMENT INTO THE CENTRAL GREAT LAKES THU NIGHT AND FRI WILL KEEP A CHANCE OF OCCASIONAL LIGHT SNOW AND SNOW SHOWERS GOING. TRS && .AVIATION DISCUSSION FOR 06Z TAFS... 1050 PM CST SFC HIGH OVERHEAD THIS EVENING WILL MOVE EAST OF THE LOCAL TERMINALS OVERNIGHT. WINDS NEARLY CALM AT MOST REPORTING SITES. THOSE CALM WINDS UNDER A SUBSIDENT AIRMASS ARE TRAPPING MOISTURE IN THE 2-3KFT ALTITUDE...WITH MVFR CONDITIONS PREVAILING AT MOST LOCATIONS. A FEW POCKETS OF CLEARING JUST W OF AN RFD-DPA LINE THIS EVENING SHOWING UP IN THE SATELLITE IMAGERY...BUT IS EXPANDING LITTLE. AREAS NEAR THAT CLEARING HAVE SEEN VIS DROP INTO THE 2-4SM RANGE...BUT AGAIN DON`T EXPECT THOSE TO REACH ORD OR MDW. OTHER THAN A BRIEF SCATTERING OUT OF CLOUDS...EXPECT MVFR CIGS TO HOLD THROUGH THE NIGHT AND INTO TOMORROW. WARM FRONT LIFTING NORTHWARD AHEAD OF APPROACHING AND DEEPENING LOW TOMORROW EVENING. ATMOSPHERIC COLUMN SATURATES RAPIDLY AS LEAD SHORTWAVE APPROACHES AROUND 00Z. TEMP PROFILES LOOK LIKE THEY SHOULD BE JUST WARM ENOUGH TO BEGIN AS RAIN AND NOT FREEZING RAIN GIVEN STRONG WAA AND LOW LEVEL TEMPS A DEGREE OR TWO ABV FREEZING...WHILE WET BULB AND DEWPOINT TEMPS START OUT INITIALLY AT 0C. FAIRLY STRONG FORCING...AND EVEN SOME WEAK INSTABILITY WITH THIS BAND...SO ADDED A TEMPO MDT RA TOWARD MIDNIGHT WED NT. && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...FLOOD WARNING PORTIONS KANKAKEE AND UPPER IL RIVERS. FLOOD WATCH TONIGHT THRU THU. .IN...FLOOD WARNING PORTIONS KANKAKEE RIVER. FLOOD WATCH TONIGHT THRU THU. .LM...NONE. && $$

AREA FORECAST DISCUSSION
NWS CHICAGO/ROMEOVILLE IL
630 AM CST WED FEB 28 2007 .DISCUSSION... 420 AM CST POWERFUL JET MAX OF 160KTS PER AIRCRAFT REPORTS CROSSING NORTHERN BAJA AT BASE OF WESTERN NOAM UPPER TROF. SATELITE SHOWS MULTIPLE CIRCULATIONS IN THE TROF. ONE LIFTING NORTHWARD ACROSS THE NORTHERN HI PLAINS WITH A TROF AXIS EXTENDING SOUTHEASTWARD ALL THE WAY TO THE LOWER MO VALLEY WHERE STRONG WAA HAS REGENTLY GENERATED ELEVATED TSRA. THE WAA PATTERN AND ASSOCIATED UVV WILL LIFT NORTHWARD INTO THE MID MS VALLEY BY THIS EVE AS THE JET MAX CROSSES THE SOUTHERN ROCKIES AND TURNS NORTHEASTWARD ACROSS THE SOUTHERN PLAINS. MODELS SHOW H8 WARMFRONT LIFTING INTO SOUTHERN WI AND LOWER MI BY 06Z AND EXPECT INITIAL ROUND OF PRECIP TO CONTINUE TO MOVE NORTHWARD INTO THE UPPER MIDWEST AND GREAT LAKES. LOWER LEVELS REMAIN RELATIVELY DRY AS THIS PRECIP AREA MOVES IN DURING THE LATER AFTERNOON AS H8 DEW POINT DEPRESSIONS WERE 20 TO 30 DEG C ACROSS THE LOWER MS VALLEY LAST EVE. 00Z RAOBS DID SHOW MARGINAL MID LEVEL MOISTURE OVER THE OZARKS AHEAD OF THE LEAD SHORT WAVE TROF WHILE LOWER LEVELS WERE DRY EXCEPT FOR SHALLOW MOISTURE ALONG THE WESTERN GULF COAST. THIS MOISTURE HAS SPREAD RAPIDLY INTO THE SOUTHERN PLAINS WHERE SURFACE DEW POINTS APPROACHING 60F AS SOUTHERLY LOW LEVEL WINDS CONTINUE TO INCREASE AHEAD OF THE RAPIDLY DEVELOPING LEE SIDE LOW BUT THIS LOWER LEVEL MOISTURE DOES NOT REACH THE MID MS VALLEY UNTIL THIS EVE. AFTER THE INITIAL SHOT OF WAA PRECIP EXPECT A BREAK UNTIL INGREDENTS COME TOGETHER OVERNIGHT. THIS INCLUDES GULF MOISTURE SPREADING INTO CENTRAL IL...DIFLUENT UPPER FLOW AS TROF BECOMES NEGATIVELY TILTED AND DIVERGENCE ALOFT AT LEFT EXIT OF STRONG JET. STEEP MID LEVEL LAPSE RATES AND STRONG DYNAMICS WILL RESULT IN CONVECTIVE RAIN BREAKING OUT AND SPREADING ACROSS THE MID MS VALLEY. PRECIPITABLE WATER VALUES CLIMB TO AROUND 1 INCH AND MODERATE TO HEAVY RAINFALL POTENTIAL DUE TO EXPECTED CONVECTIVE NATURE AND FLOOD WATCH WILL BE CONTINUED GIVEN ALREADY SOME FLOODING PROBLEMS AND MOISTURE CONTENT OF SNOWPACK. UPPER LOW LINGERING OVER THE CANADIAN MARITIMES SLOWS THE PROGRESS OF THIS STORM AND IT BECOMES STACKED DURING THU AS IT LIFTS INTO IA. WINDS WILL GRADUALLY DIE DOWN AS LOW STARTS GRADUAL FILLING. DRY SLOT PUNCHES NORTHWARD DURING THU WITH OCCLUDED FRONT SWEEPING EAST AND NORTHEAST THRU THE FA. THIS WILL CURTAIL RAIN BUT WITH COLD AIR WRAPPED INTO SYSTEM AND IT/S SLOW MOVEMENT INTO THE CENTRAL GREAT LAKES THU NIGHT AND FRI WILL KEEP A CHANCE OF OCCASIONAL LIGHT SNOW AND SNOW SHOWERS GOING. TRS && .AVIATION DISCUSSION FOR 06Z TAFS... 630 AM CST THE CYCLONE WAS OVER COLORADO THIS MORNING AS SEEN ON THE SURFACE MAP AT 12 UTC. THE 850 MB 12 UTC ANALYSIS SHOWS A 50 KNOT WIND IN WESTERN MISSOURI. THE WATER VAPOR LOOP SHOW THE RAPID EASTWARD MOVEMENT OF THE TROUGH INTO THE WESTERN UNITED STATES. THIS CYCLONE IS GOING TO BE A VERY DYNAMIC SYSTEM. THE LOCALLY RUN WRF ARW MODEL SHOWS THE STRONG 850 MB WIND WILL MOVE INTO ILLINOIS. THE EQUIVALENT POTENTIAL TEMPERATURE HAS A LARGE GRADIENT TONIGHT AS THE WARM AIR RETURNS TO CENTRAL ILLINOIS. THE NEGATIVE OMEGA AT 700 MB IS FORECAST TO BE LARGE BETWEEN 09 AND 12 UTC THURSDAY MORNING. THE LIFTED INDEX GRADIENT IS LARGE IN CENTRAL ILLINOIS AS WELL. WILL KEEP THE WIND FORECAST 15 KNOTS WITH GUST TO 24 KNOTS TONIGHT. WE EXPECT SOME REAL UNSTABLE AIR MOVING INTO THE TAF FORECAST AREA. SO WILL ADD THUNDERSTORMS TO THE FORECAST BETWEEN 8 TO 12 UTC. THIS EVENING... AS THE ISENTROPIC LIFT BEGINS MIXED PRECIPITATION MAY OCCUR WITH RAIN AND SNOW AND POSSIBLY ICE PELLETS. THE WRF FROM NCEP...GFS AND NGM MODELS WERE USED AND THE LOCAL WRF ARW WAS ALSO USED. && .LOT WATCHES/WARNINGS/ADVISORIES... .IL...FLOOD WARNING PORTIONS KANKAKEE AND UPPER IL RIVERS. FLOOD WATCH TONIGHT THRU THU. .IN...FLOOD WARNING PORTIONS KANKAKEE RIVER. FLOOD WATCH TONIGHT THRU THU. .LM...NONE. && $$