FLORIDA KEYS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KEY WEST FL 1015 PM EST MON JAN 27 2003 CURRENTLY... SURFACE PRESSURE ARE RISING REGIONALLY...AND WINDS HAVE RESPONDED AS FORECAST WITH NOTICEABLE INCREASES SINCE SUNDOWN. UPPER KEYS REPORTING SITES INDICATE WINDS THERE...WHICH WERE OUT-OF-LINE TOO LIGHT EARLIER...ARE NOW BLOWING FROM THE NORTH NEAR 20 KT...SAME AS OTHER MID AND LOWER KEYS SITES. NW FLORIDA BAY PLATFORM ONLY REPORTS WINDS 10 KT PAST HOUR...BUT ON THE OTHER HAND...FLAMINGO ON THE MAINLAND COAST HAS SUDDENLY PICKED UP GUSTS TO 16 KT THIS HOUR. FINALLY...TO OUR NORTH WINDS ARE QUITE STRONG AT FOWEY ROCK THIS HOUR...NORTH 26 KT GUSTS TO 32 KT. IR SATELLITE SHOWS CIRRUS FLOW STILL OVERHEAD...WITH UPSTREAM CIRRUS COMING AT US FROM THE GULF AND ACROSS MEXICO. TEMPS CONTINUE TO HOVER AT 59-60F...SINCE SUNDOWN. OVERNIGHT... 1030 PM COASTAL WATERS FORECAST CONTAINS NO CHANGES...JUST ELIMINATION OF "EARLY" TRANSITIONAL WORDING. LATEST 18Z MESOETA/GFS AND RUC TOO...CONTINUE WITH INDICATIONS OF INCREASED N WINDS TURNING MORE TO NE TOWARD SUNRISE BUT MAINTAINING SPEEDS NEAR 20 KT. PUBLIC ZONES WILL NOT BE UPDATED. ALL IS GOOD. .EYW...SCA ALL WATERS. C.B. fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 1005 PM CST MON JAN 27 2003 THANKS TO DVN FOR SUPPORING US TODAY. THE ETA NAILED THE H8 THERMAL PATTERN THIS EVENING...BTR THAN THE AVN AND RUC. WE ARE 50 DEGREES AT 3500 FEET WHICH IS QUITE IMPRSV FOR THE COLDEST TIME OF YEAR. STG FRONTOGENETIC FORCING IS ON THE HORIZON TMR AS A VRY STG H8 BNDRY SETS UP IN FAR NRN MO/XTRM SRN IA. NEW RUNS HAVE NEARLY DOUBLED THE QPF...WHICH SHOULD STILL OK CONSIDERING HOW OVERDONE THE ETA QPF HAS BEEN LATELY. STILL SOMETHING NOT TO DISPUTE LOOKING AT ALL THE HI RES MDL RUNS FM 12Z. HAVE SLIPPED THE ADVISORY TWO TIERS S FOR TMR. REMOVED THE SNOW MENTION WITH SLEET N OF HIWAY 30 AT TIMES. MORE TIMING INFO IS ALRDY IN THE ADVISORY. .DSM...WINTER WX ADV FOR FREEZING RAIN LATE TONIGHT AND TUESDAY NORTH OF I80. WINTER WX ADV S OF I80 EXCLUDING SRN TIER TUESDAY. MYERS ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 900 PM CST MON JAN 27 2003 OVERNIGHT TEMP FORECAST WILL BE TRICKY TONIGHT. WARM AIR ADVECTION AND 925 MB MOISTURE AND ASSOCIATED CLOUD DECK INVADING FROM THE SW. APPEARS SOME WESTERN PORTIONS HAVE ALREADY REACHED THE OVERNIGHT LOWS AND ON WAY UP. WILL NEED TO WORD SLOWLY RISING OR STEADY OVERNIGHT FOR MUCH OF AREA. WILL GO SOUTH WINDS 5 TO 10 MPH MOST OF AREA...AROUND 10 WEST. SKY CONDITIONS TO VARY FROM CLOUDY TO BECOMING MOSTLY CLOUDY. ACTUAL MOISTURE INVASION AT 925 MB APPEARS TO BE COMPROMISING BETWEEN FASTER MESOETA AND SLOWER RUC/NGM. VII .SHV...NONE. la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1005 PM EST MON JAN 27 2003 ...CANCELED THE WINTER WEATHER ADVISORY FOR NW COUNTIES... THE QUESTION IS WHAT SHOULD WE DO WITH THE WINTER WEATHER ADVISORY TONIGHT? WE NEED 4 TO 5 INCHES TO FALL IN 12 HOURS OR LESS OR A MIX OF SNOW AND ICE (OF CONSEQUENCE) TO KEEP IT IN EFFECT. SINCE AFTER MAKING A FEW PHONE CALLS TO MASON AND OCEANA COUNTIES ONLY 1 TO 2 INCHES HAS BEEN REPORTED ALL DAY AND SINCE THE DEEP MOISTURE IS ALREADY MOVING OUT. SINCE THE SYNOPTIC LIFT EVENT IS JUST ABOUT OVER...(SEE IR AND RADAR LOOPS) AND SINCE WARM ADVECTION WILL SOON KILL THE LAKE EFFECT ENHANCEMENT...I DO NOT BELIEVE THERE WILL BE ENOUGH SNOW TO REACH THAT 4 INCH IN 12 HOUR THRESHOLD. I DO BELIEVE THERE WILL BE SOME PATCHY FREEZING DRIZZLE (SEE BELOW)... BUT THAT SHOULD BE RATHER LIGHT AND NOT A BIG ISSUE GIVEN THERE IS SNOW ON THE GROUND IN MOST AREAS OF SOUTHWEST MICHIGAN. SINCE THE DEEP MOISTURE/WARM ADVECTION LIFT PART OF THE EVENT IS ALREADY MOVING EAST OF THE GRR CWA...AND 00Z RAOBS PLUS RUC AND ETA CROSS SECTIONS SHOW A WARM/DRY LAYER BETWEEN 850 AND 700 MB MOVING IN FROM THE SOUTHWEST THE SIGNIFICANT PRECIPITATION EVENT IS ABOUT OVER...IF IT EVER STARTED IN THE FIRST PLACE. THE WARM ADVECTION ASSOCIATED WITH THE WARM FRONT BRINGS THE 1000 MB TO 850 MB TEMPERATURES ABOVE -12C BTW 06Z AND 09Z OVER THE WESTERN CWA. THAT WILL END ANY POTENTIAL FOR LAKE SNOW DEVELOPMENT EVEN WITH THE SOUTHWEST WINDS BELOW 850 MB BY 09Z FOR SURE. SINCE THERE WILL BE LITTLE IN THE WAY OF MOISTURE BETWEEN THE 850 LEVEL AND THE 700 MB LEVEL...THERE WOULD BE TO MUCH OF A DRY LAYER FOR MUCH SEEDING OR FEEDING EITHER. BOTTOM LINE TO THIS IS THE LIGHT SNOW...BE MIXED AT TIMES WITH SLEET (PHONE CALLS TO OFFICE AND LAN METAR) THEN CHANGE TO VERY LIGHT PATCHY FREEZING DRIZZLE ONCE THE -12C ISOTHERM IS NO LONGER IN THE LAKE CLOUDY LAYER AFTER MIDNIGHT. BOTTOM LINE IS WE HAVE ALREADY DROPPED THE WINTER WEATHER ADVISORY FOR THOSE NORTHWEST COUNTIES. THE MIDNIGHT SHIFT MAY HAVE TO RE-ISSUE A WINTER WEATHER ADVISORY FOR FREEZING DRIZZLE IF THAT REALLY DOES GET GOING BUT AT THIS POINT WITH DEW POINTS AT THE SURFACE ON THE WI SIDE OF THE LAKE STILL NEAR OR BLEW 10F... HARD TO BELIEVE THE DRIZZLE EVENT WILL BE MUCH EITHER. I WILL FORECAST RISING TEMPERATURES OVERNIGHT...BASED ON WINDS BECOMING MORE SOUTH SOUTHWEST TOWARD MORNING BRINGING THE WARMER UPSTREAM AIR INTO OUR CWA. ZONES BY 1015 PM. .GRR...NONE. WDM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 920 PM EST MON JAN 27 2003 00Z RAOBS/LATEST WV LOOP AND RUC ANLSYS SHOW WNW FLOW ALF OVR NW GRT LKS BTWN UPR RDGING IN WRN CAN AND TROF OVR THE E. SHRTWV EMBEDDED WITHIN THIS FLOW NOW MOVG JUST E OF LK SUP IN ONTARIO...AND BROAD AREA OF ISENTROPIC LIFT IN ADVANCE OF THIS SYS THAT GENERATED SN OVR THE CWA TDAY HAS SHIFTED TO E AS INDICATED BY COLDER CLD TOPS ON IR SAT PIX/DEEPER MSTR. 00Z APX SDNG WITHIN THE WAD PATTERN/MOIST AIRSTREAM SHOWS DEEP SATURATION THRU THE TROP. 00Z INL SDNG SHOWS NR SATURATED LYR BLO CONSIDERABLE DRYING ABV H85. PIREP FM NR CMX... WHERE MID LVL DRY AIR HAS MOVD IN PER IR SAT PIX HIER TEMPS... INDICATES CLD RATHER THIN UNDER DRYING ALF...ONLY 1 TO 2K FT DEEP. SO NOT SURPRISED THAT OBS/88D INDICATE LTL IF ANY PCPN OVR CWA W OF MUNISING TO ESC. LK ENHANCED SN HAS PLAGUED SCHOOLCRAFT/LUCE COUNTIES THIS EVNG AS SYNOPTIC FORCG HAS COMBINED WITH STRG S FLOW OFF LK MI. 00Z GRB SDNG SHOWS MIXED LYR UP TO H875...NO DOUBT LIFTED HIER BY LATENT/SENSIBLE HEAT OVR NRN LK MI E OF GRB. INTENSITY OF LES HAS BEEN ENHANCED BY CNVGC BTWN SW FLOW OVR THE CWA AND SE WND OVR THE ERN CWA. SPOTTER RPRT FM ISQ AND GULLIVER IN FAR ERN SCHOOLCRAFT COUNTY INDICATE SN RATES AS HI AS AN INCH OR TWO/HR... WITH S WND GUSTS OVR 30 MPH CAUSING WHITEOUT CONDITIONS. GULLIVER RPRT AT 7 PM INDICATED ARND 8 INCHES ACCUMULATION TO THAT POINT AFTR SN STARTED DURG AFTN. HOWEVER...LATEST OB FM ISQ SHOWS WND HAS SHIFTED TO WSW BEHIND BACK EDGE OF ENHANCED CLD...SUGING LLVL CNVGC AND LES WL DIMINISH DURG NXT FEW HRS AS SYNOPTIC SUPPORT SHIFTS E WITH SHRTWV. ANOTHER SFC LO MOVG THRU FAR NW ONTARIO ASSOCIATED WITH SHRTWV OVR HUDSON BAY...WITH TRAILING COLD FNT XTNDG SW INTO NRN MN. SFC OBS SHOW SOME LGT SN AHD OF THIS BNDRY. MAIN FCST CONCERNS THIS UPDATE INCLUDE SN TRENDS OVR THE ERN CWA... GOING WINTER STORM WRNG FOR LUCE/SCHOOLCRAFT COUNTIES...TEMPS AND WINDS/GALE WNRG ON ERN LK SUP. 18Z ETA/00Z RUC SHOW ONTARIO SHRTWV MOVG STEADILY E OVRNGT WITH DRY AIR ABV H85 FILLING IN AND LLVL FLOW TENDING TO VEER WITH TIME IN WAKE OF SYS. AXIS OF SHARP H95 CNVGC DEPICTED BY 18Z ETA FOR 00Z-03Z IN ERN CWA APPEARS RIGHT ON TARGET...AND MODEL SHOWS SHARP LLVL CNVGC CLRG ERY/FAR ERN SCHOOLCRAFT COUNTY ARND 03Z AND ALL OF LUCE BY 05Z. THUS XPCT SYNOPTIC SN HAS ENDED WITH TIMING OF DEPARTURE OF LES IN LUCE/SCHOOLCRAFT FCST CLOSE TO 18Z ETA GUIDANCE. WL CANCEL WINTER STORM WRNGS AS MAIN LES BAND NOW SHOWN WELL ON 88D FOLLOWING DEPARTURE OF DEEP MSTR SHIFTS E OF RESPECTIVE COUNTIES. TO THE W...ONLY OTHR PCPN CONCERN WL BE COLD FNT TRAILING FM SFC LO OVR FAR NW ONTARIO. 18Z ETA AND 00Z RUC SHOW THIS BNDRY REACHING WRN ZNS ARND 09Z. HOWEVER...RUC FCST H85-5 QVECTOR DVGC/ H3-2 CNVC COINCIDENT WITH FROPA SUGS ANY PCPN ACCOMPANYING ITS ARRIVAL WL BE ON THE LGT SIDE. THERE MAY BE SOME ENHANCEMENT OF PCPN OVR THE KEWEENAW ZNS WITH FCST W FLOW. SINCE NO FZDZ OBSVD UPSTREAM AND ETA FCST SDNGS FOR CMX SHOW -10C ISOTHERM WITHIN TOP OF FAIRLY SHALLOW MOIST LYR...THINK PCPN TYPE WL BE -SN/FLURRIES AND HAVE REMOVED MENTION OF FZDZ. AS FOR TEMPS...LLVL FLOW WL REMAIN WSW ALL NGT...AND TEMPS TO THE W AND SW ARE GENERALLY IN THE TEENS. SINCE ABUNDANT LLVL MSTR DEPICTED ON THE INL SDNG SUGS SKIES WL REMAIN CLDY DESPITE UPR LVL DRYING...GOING FCST TREND FOR TEMPS TO REMAIN STEADY/SLOWLY RISE APPEARS ON TRACK. NO CHGS NECESSARY ON TEMPS ATTM. SFC OBS INDICATE SHARPEST PRES GRADIENT IN ADVANCE OF SHRTWV HAS SHIFTED E OF MOST OF ERN LK SUP. OB FM STDM4 SHOWS SHARP DCRS IN WND SPEED BTWN 00Z/01Z. SINCE ETA/RUC ADVERTISE DIMINISHING LLVL WNDS WITH FLATTER PRES GRADIENT OVR THE LK DURG NGT...WL CANCEL GOING GALE WRNG FOR THE E HALF WITH 03Z UPDATE. AFDMQT FM DAYSHIFT FOR LATER PDS... BEHIND THE TROUGH ON TUESDAY...THE ETA AND GFS SHOW SUBSIDENCE BUILDING INTO THE AREA AS WEAK HIGH PRES BUILDS INTO THE NRN PLAINS. BEHIND THIS TROUGH...COOLER AIR STARTS TO FILTER INTO THE AREA...WITH 850MB TEMPS TO -18C BY 00Z. THIS CAA WILL END ANY FREEZING DRIZZLE. STILL...PROBABLY BEST CHANCE FOR ANY FREEZING DRIZZLE IN THE MORNING WILL BE OVER THE KEWEENAW WHERE BEST UPSLOPE AND LOW LVL CVRG EXISTS. AS COLDER AIR FILTERS INTO THE NW CWFA...SCT-NUM LES SHOULD PICK UP DUE TO LAKE-H85 DELTA-T VALUES RISING TO 20C BY EVENING. REALLY NOT MUCH SYNOPTIC SUPPORT UNDER WEAKENING BROAD ANTICYCLONIC FLOW...SO WILL CUT ACCUMULATIONS DOWN SOMEWHAT OVER THE NORTHWEST. GENERALLY LESS THAN 2 INCHES. OTHERWISE...OTHER LAKESHORE AREAS WILL HAVE SCT SNOW SHOWERS OR FLURRIES IN THE AFTERNOON. NO MAJOR CHANGES PLANNED FOR TUE NIGHT WITH NW FLOW AND DELTA-T VALUES REMAINING AROUND 20C. WITH WIND STAYING UP IN THE 10-15 MPH RANGE...AND CLDS NEAR THE LAKE...TEMPS WILL NOT GET TOO COLD...GENERALLY NEAR NORMAL. WITH THE RIDGE BUILDING TO THE NORTH OF THE CWFA...THE WINDS MIGHT TURN AROUND TO 340-350 OVER THE CENTRAL LAKE. THIS MAY BE JUST ENOUGH TO CAUSE SOME BANDS TO MOVE INTO EASTERN MQT COUNTY. WITH THE WINDS NNE OVER THE FAR EAST...LUCE COUNTY MAY END UP BEING SHADOWED FROM GREATEST SNOW. WILL THEREFORE GO WITH BEST SNOW ACCUMULATIONS OVER WESTERN ALGER AND ONTONAGON COUNTIES. IT REMAINS VERY DRY ALOFT WITH INVERSION HEIGHTS LOWER THAN 4 KFT...SO SIG ACCUMULATIONS ARE NOT EXPECTED. ARCTIC FRONT MOVES TROUGH THE AREA ON WED. MIGHT BE A QUICK BURST OF SNOW WITH THE FRONT...ALTHOUGH NEITHER THE GFS OR ETA SNOW STRONG CVRG WITH THE FRONT (WIND ACTUALLY ENDS UP BACKING BY 21Z IN RESPONSE TO THE FAST MOVING HIGH MOVING INTO THE CENTRAL PLAINS). THERE IS SOME H8-H7 Q-VECT CVRG WITH THE MAIN VORT...SO WOULD NOT BE SURPRISED TO SEE SOME LIGHT SNOW REACH MENOMINEE. WILL THEREFORE GO WITH LIKELY POPS NEAR THE LAKE...AND CHC POPS ELSEWHERE. MAIN IMPACT OF THE FRONT WILL BE TO DROP H85 TEMPS TO -24C FOR A SHORT TIME WED NIGHT. THINK THAT AS THE HIGH SHIFTS TO THE SOUTH AND EAST OF THE CWFA WED NIGHT IN THE FAST FLOW ALOFT...LES WILL STOP DUE TO H85 TEMPS WARMING IN MODEST WAA...AND WINDS BACKING TO THE SW. THE KEWEENAW WILL KEEP SNOW AROUND THE LONGEST. WILL GO DRY ON THU AS WAA CONTINUES AHEAD OF THE S/WV ENTERING THE PLAINS. MOISTURE PROFILES SHOW A VERY DRY ATMOSPHERE AHEAD OF THE SYSTEM...SO DESPITE SOME WEAK ISENTROPIC LIFT...ATMOSPHERE REMAINS TOO DRY FOR ANY PCPN UNTIL LATER THU NIGHT. OVERALL...TEMPS WILL REMAIN AT OR SLIGHTLY ABOVE NORMAL FOR EVERY DAY OF THE SHORT TERM EXCEPT WED. COLDEST MIN TEMP WILL MOST LIKELY BE ON WED NIGHT...HOWEVER WINDS SHOULD HELP TO KEEP TEMPS IN CHECK. FOR THE EXTENDED(FRI-MON)...STILL LOOKS LIKE FA WILL HAVE GENERALLY NEAR OR SLIGHTLY ABV NORMAL HEIGHTS. GFS ENSEMBLE RUNS ARE IN FAIR AGREEMENT WITH THE OPERATIONAL GFS AND OTHER MED RANGE MODELS IN A RETROGRESSIVE PATTERN...HAVING THE WEST COAST RIDGE SHIFT SLIGHTLY TO THE WEST...CAUSING THE MEAN UPR TROUGH AXIS TO BE CENTERED MORE OVER THE CENTRAL US...OPPOSED TO THE EASTERN US LIKE THE PAST SVRL WEEKS. THIS WILL ALLOW THE SFC LOW TRACK TO MOST LIKELY SHIFT A LITTLE FURTHER WEST (ALTHOUGH THIS HAS NOT HAPPENED YET THIS YEAR). SO...REALLY NO MAJOR CHANGES IN THE EXTENDED FORECAST. ENSEMBLES ARE IN FAIR AGREEMENT IN A FAST MVNG S/WV TO SWING THRU THE AREA FRI...CAUSING SOME LIGHT SNOW TO AFFECT THE AREA. A STRONGER WAVE MOVES THRU SAT...WITH MORE LIGHT SNOW. SUNDAY MIGHT END UP BEING A DRY DAY...WITH THE OPERATIONAL GFS AND ENSEMBLES SHOWING RIDGING AHEAD OF THE STRONGER S/WV MOVING OUT OF THE SW ON MONDAY. WILL THEREFORE OPT TO REMOVE PCPN FROM FCST ON SUNDAY...AND WARM THE TEMPS UP SLIGHTLY. THE GFS AND IT/S ENSEMBLES ARE IN FAIR AGREEMENT IN SOME TYPE OF A COLORADO LOW DEVELOPING AND MOVING INTO THE WESTERN GREAT LAKES. OF COURSE...THE TRACK IS HIGHLY UNCERTAIN...BUT AN EASTERN TRACK WOULD BE THE BEST GUESS NOW GIVEN THE STORM TRACK ALL WINTER. FOR NOW...WILL GO WITH CHC OF SNOW ON MONDAY...WITH TEMPS NEAR NORMAL. OVERALL...ABV NORMAL MIN TEMPS. .MQT...HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. KC mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1140 AM EST MON JAN 27 2003 ...LAKE ENHANCED SNOW OVR SE IS MAIN CONCERN... VIS SAT THIS MORNING SHOWS ALTOSTRATUS SPREADING INTO WRN UPR MI ASSOCIATED WITH BAND OF BROAD ISENTROPIC ASCENT ON WRN PERIFERY OF EXITING HIGH PRES...NOW CENTERED OVER OHIO VALLEY. LIFT IS OCCURRING IN WAD ZONE OF SFC TROUGH FM MAN INTO DAKOTAS. MAIN FOCUS THOUGH IS OVR EXTREME SE CWA WHERE POTENTIAL EXISTS FOR HEAVY LAKE ENHANCED SNOW LATE AFTN-EVENING. VIS SAT ALREADY SHOWING ISOLATED SNOW BAND FILTERING INTO SRN SCHOOLCRAFT EAST OF MANISTIQUE TO MACKINAC COUNTY LINE. VSBY DROPPED BRIEFLY TO 1/2SM AT ISQ AT 13Z WITH VSBY AT KSJX (BEAVER ISLAND) OCCASIONALLY BLO 3SM. SYNOPTIC SNOW HAS REACHED AS FAR E AS KASX AS OF 1630Z. RUC HAS BEST HANDLE ON LOW LEVEL WINDS WHICH WILL BE CRITICAL FOR SPECIFICS OF LAKE ENHANCEMENT. RUC AND EVENTUALLY ETA DEPCIT SSW WIND THROUGH AT LEAST 4KFT DEVELOPING BY 21Z. BLYR WINDS OVR NRN LK MI INCREASE TO 35KT BY 00Z...WITH 15KT OVR LAND AREAS. THIS SHOULD ALLOW SNOW BANDS OVR SERN SCHOOLCRAFT (GULLIVER-BLANEY PARK) TO REACH 30 MI TO NNE ALONG M-28 FROM MCMILLIAN TO NEWBERRY. PROFILES FROM A SNOW GROWTH POINT OF VIEW BECOME VERY FAVORABLE THIS EVENING AS SHORTWAVE/DEEPER MOISTURE (CURRENTLY NOSING INTO NRN MN AND NW ONT) SPREAD OVER AREA. H85-H5 REMAIN AROUND -16C...WITH FAVORABLE SNOW GROWTH AREA FM H9-H5. ALTHOUGH HIGHER WINDS WILL DETER ORGANIZATION TO INDIVIDUAL BANDS...LAKE ENHANCEMENT SCENARIO IS NOT AS DEPENDENT ON THAT AS PURE LES. OTHER POSITIVE FACTOR FOR SIG SNOW IN THIS AREA INCLUDE ADDED LOW LEVEL CONVERGENCE DUE TO SSW WIND OVER LK MI AND SSE WIND NEAR NWRN LOWER MI (BEAVER ISLAND TO GRAND TRAVERSE BAY). ASCENT DUE TO SHORTWAVE AND UPR MI IN LFQ OF UPR JET IS MAXIMIZED BTWN 02Z-06Z...AND SINCE THIS AM IN SRN MAN/NW ONT VSBY HAS BEEN BLO 1SM AHEAD OF WAVE...WILL LIKELY SEE 1"+ (POSSIBLE 2-3") PER HOUR RATES OVER ENHANCEMENT TARGETED AREA THIS EVENING. HAVE BOOSTED SNOW ADVY TO WARNING BANKING ON EXTREMELY HEAVY SNOW THIS EVENING PUSHING SOME LOCALES OVR 8"/12HR CRITERIA. INCREASING WINDS WILL ALSO POSE BLOWING/DRIFTING SNOW HAZARD. OTHERWISE...BROAD SCALE ISENTROPIC ASCENT WILL SPREAD A GENERAL 1-2" OF SNOW OVR CWA BEGINNING SHORTLY OVR FAR WRN ZONES THEN INTO CNTRL/ERN ZONES BY LATE AFTN (285-290K SFCS SHOW ASCENT BEST). WOULD EXPECT HIGHEST AMOUNTS OVR NRN TIER (CLOSEST TO PERIFERY OF WSW MOVING SHORTWAVE THAT CROSSES LK SUPERIOR THIS EVENING). SHORTWAVE/UPR JET AND ASSOCIATED LARGE SCALE ASCENT DIMINISHES FM W (AROUND 03Z) TO E (AFT 06Z) WITH WIND SHIFT OCCURING AFT 06Z. HEAVY SNOW SHOULD QUICKLY END OVR SERN ZONES...WITH JUST FLURRIES LINGERING OVER REST OF CWA. COORD WITH APX...THANKS. .MQT...WINTER STORM WARNING LATE THIS AFTN AND EVENING MIZ007-014. HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. GALE WARNING E 1/2 LAKE SUPERIOR. JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1103 AM EST MON JAN 27 2003 MID MORNING SURFACE ANALYSIS SHOWING 1039MB SURFACE HIGH OVER SOUTHERN OH...RIDGING NORTHEAST INTO THE EASTERN GREAT LAKES. NORTH-SOUTH ORIENTED WARM FRONT EXTENDS FROM THE WESTERN DAKOTAS SOUTH INTO KS/OK. INTERFACE BETWEEN COLD AIR DRAINAGE FROM ONTARIO AND INFLUENCE OF WARMER LAKE WATERS MANIFESTED IN NORTHWEST-SOUTHEAST ORIENTED TROUGH AXIS ACROSS LAKE HURON/EASTERN UPPER...ALONG WHICH A VERY PERSISTENT SNOW BAND HAS BEEN CONCENTRATED THROUGH THE NIGHT OVER LAKE HURON BETWEEN THE TWO PENINSULAS. LOW LEVEL RIDGING WILL BUILD ACROSS THE FORECAST AREA DURING THE LATE MORNING/EARLY AFTERNOON HOURS...FOLLOWED BY TIGHT BAROCLINIC ZONE ASSOCIATED WITH APPROACHING WARM FRONT. FORECAST CONCERNS TODAY DEAL WITH INITIAL NUISANCE CONVECTION...THEN POTENTIAL FOR LAKE ENHANCED SNOWFALL LATER THIS AFTERNOON. 12Z APX SOUNDING INVERSION HEIGHT AROUND 4K FEET WITH 850MB TEMPERATURES AROUND -22C. KAPX VWP SHOWING WINDS IN LOWEST THREE GATES HAVE COME AROUND TO THE SOUTHWEST...AND RADAR RETURNS OVER LAKES MICHIGAN/HURON BEGINNING TO REFLECT THIS AS WELL. PERSISTENT LAKE HURON BAND STARTING TO SHIFT NORTH...WITH SOUTHWEST ORIENTED CONVECTIVE CELLS NOW SHOWING UP BETWEEN BEAVER ISLAND AND GRAND TRAVERSE BAY. UPSTREAM RADARS SHOW INITIAL BATCH OF RETURNS CROSSING WESTERN UPPER/CENTRAL WI...BUT MOSTLY VIRGA AT THIS POINT AS LOW LEVELS ARE DRY ON GRB/DVN SOUNDINGS (I.E., 850MB DEW POINT DEPRESSIONS FROM 10-20C). OF COURSE THE DEPTH OF THIS DRY LAYER WILL SHRINK OVER LAKE MICHIGAN... SO THAT WE SHOULD START TO SEE AN INCREASE IN SNOW COVERAGE OVER LAKE MICHIGAN AND LAKESHORE COUNTIES IN THE 18-20Z TIME FRAME...THOUGH POTENTIAL FOR STRONGER ENHANCEMENT WILL PROBABLY OCCUR BEYOND 22Z. THIS IS A COUPLE HOURS QUICKER THAN RUC/ETA MODEL SOUNDINGS WOULD IMPLY... BOTH MODELS HAVE ABOUT A 5K FOOT DRY LAYER OVER LAKE MICHIGAN AT 21Z BUT SUSPECT FROM SATELLITE TRENDS THAT MID LEVELS MAY MOISTEN UP A BIT QUICKER. WILL NOT CHANGE SNOW ACCUMULATIONS AT THIS POINT...THOUGH THINK THE 4 INCH TOP END FOR THIS AFTERNOON MAY BE A BIT HIGH AS THE GOOD SNOWFALL RATES GET CRANKING CLOSER TO 00Z WITH IMPRESSIVELY DEEP (300MB) ISOTHERMAL LAYER AROUND -16C 00Z A BIG PLUS FROM A SNOWFLAKE GROWTH STANDPOINT. WILL ADD IN A MENTION OF SNOW SHOWERS AROUND DRUMMOND ISLAND AS WELL AS LAKE HURON BAND GETS NUDGED INLAND. INTERIOR NORTHEAST LOWER AREAS STARTING OUT SUNNY WILL CLOUD UP WITH COMBINATION OF DIURNAL SC AND RESIDUAL LAKE CLOUDS ADVECTING IN FROM SOUTHWEST LOWER. WILL PROBABLY REMOVE POPS ALONG I-75 CORRIDOR FROM GLR SOUTH AS MEASURABLE SNOW ARRIVES IN THE 22Z-00Z TIME FRAME. AFTERNOON HIGHS IN THE 10-15 DEGREE RANGE AREAWIDE. NO CHANGES TO HEADLINES...AT THIS POINT WILL JUST HAVE TO SEE HOW THIS STARTS TO PLAY OUT. UPDATED ARBZFPAPX WILL BE OUT BY 1630Z. .APX...WINTER STORM WARNING...THIS AFTERNOON AND EVENING... WINTER WEATHER ADVISORY...THIS AFTERNOON AND EVENING... JPB mi AREA FORECAST DISCUSSION...MESOSCALE UPDATE NATIONAL WEATHER SERVICE JACKSON MS 830 PM CST MON JAN 27 2003 LIGHT WINDS AND CLEAR SKIES HAVE ALLOWED FOR RAPID COOLING ACROSS MOST OF THE CWA. AS OF 8 PM...TEMPS HAVE FALLEN INTO THE MID 30S OVER MUCH OF CENTRAL AND SOUTH MS. TEMPS IN NE LA AND SW MS HAVE FALLEN INTO THE LOWER 40S. LOW TEMPS WILL NEED TO BE LOWERED A CAT JUST ABOUT EVERYWHERE. THE LATEST 11-3.9 MICRON SATELLITE IMAGERY DEPICTS LOW CLOUDS OVER EAST TX AND WESTERNMOST LA. THIS AREA OF CLOUDINESS HAS NOT MADE MUCH OF AN EASTWARD PROGRESSION THUS FAR THIS EVENING. 00Z/28 RAOBS AND 02Z/28 RUC DATA DEPICT A GOOD DEAL OF DRY AIR OVER EASTERN LA AND MOST OF MS. AT THIS POINT...IT APPEARS THAT CLOUD COVER WILL GRADUALLY INCREASE OVER WESTERN PORTIONS OF THE CWA DURING THE EARLY MORNING HOURS. THIS WILL ALLOW FOR COOLER LOW TEMPS IN THE DELTA AND NW PORTIONS OF THE CWA. EXPECT LOW TEMPS TO BE ACHIEVED JUST AFTER MIDNIGHT IN THIS AREA WITH STEADY OR SLOWLY RISING TEMPS AS THE CLOUD DECK AND LIGHT SOUTHERLY FLOW TAKES HOLD. WILL GO AHEAD AND DROP LOW TEMPS A CAT FOR ENTIRE CWA. GRIDS AND ZONES OUT SHORTLY. GAGAN *****PREVIOUS DISCUSSION***** MAIN FORECAST THIS PACKAGE CENTERS AROUND THE RAIN CHANCES BEGINNING TUESDAY NIGHT AND CONTINUING THROUGH FRIDAY. CURRENT SURFACE ANALYSIS HAS HIGH PRESSURE CENTERED JUST WEST OF THE APPALACHIAN MOUNTAINS STRETCHING SOUTHWEST INTO NORTHEAST MISSISSIPPI. THIS HIGH WAS PROVIDING LIGHT WINDS AND CLEAR SKIES ACROSS THE AREA THIS AFTERNOON. THE HIGH WILL CONTINUE SLIDING TO THE EAST THE NEXT SEVERAL DAYS. THIS WILL RESULT IN SOUTH TO SOUTHWEST WINDS THAT WILL INCREASE IN SPEED TUESDAY AFTERNOON AND BEGIN TO RETURNING MOISTURE INTO OUR AREA. THE WARM SOUTHERLY WINDS TUESDAY WILL HELP MOST SITES CLIMB INTO THE 60S. DEW POINT IN THE TEENS THIS AFTERNOON WILL RECOVER TO THE 40S BY TUESDAY EVENING. TUESDAY NIGHT ANOTHER COLD FRONT WILL APPROACH THE DELTA REGION AND BRING THE NEXT CHANCE FOR RAIN. ONLY .05 OF AN INCH OF RAIN HAS BEEN RECORDED SO FAR THIS MONTH AT JAN. THE DRIEST JANUARY ON THE RECORD AT JAN ONLY RECORDED .75 OF AN INCH OF RAIN. IT APPEARS THAT THIS RECORD MAY BE SAFE AS THE MODELS HAVE TRENDED TOWARD A WET ENDING TO THIS MONTH. THE COLD FRONT WILL MOVE ACROSS THE AREA WEDNESDAY BEFORE STALLING ACROSS SOUTHERN MISSISSIPPI WEDNESDAY NIGHT. ENOUGH MOISTURE AND INSTABILITY ARE EXPECTED TO PRODUCE A FEW THUNDERSTORMS WEDNESDAY AFTERNOON. A COUPLE OF SHORT WAVES WILL MOVE OVER THE LOWER MISSISSIPPI VALLEY THURSDAY AND FRIDAY. THIS WILL HELP GENERATE A SURFACE LOW OUT OF EAST TEXAS THAT WILL RIDE ALONG THE FRONT THURSDAY AND PRODUCE ANOTHER CHANCE FOR THUNDERSTORMS THURSDAY AFTERNOON. THE SECOND SHORT WAVE WILL MOVE ACROSS THE AREA FRIDAY AFTERNOON RESULTING IN ANOTHER CHANCE FOR RAIN BEFORE THINGS DRY OUT AND HIGH PRESSURE BUILDS BACK IN FOR THE WEEKEND. THE START OF GROUND HOG DAY LOOKS TO BE MOSTLY SUNNY HERE BUT CLOUDS WILL INCREASE SUNDAY NIGHT AHEAD OF THE NEXT COLD FRONT AND NEXT CHANCE FOR RAIN MONDAY. PRELIM NUMBERS... JAN 33/63/52/60/47 00374 MEI 29/62/49/60/46 00374 .JAN... AR...NONE. LA...NONE. MS...NONE. 22 ms NORTHEAST MONTANA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE GLASGOW MT 915 AM MST MON JAN 27 2003 .SHORT TERM...PACIFIC COOL FRONT MIXED OUT ALL AREAS INTO THE 40S OVERNIGHT...SO CALENDAR DAY HIGHS HAVE ALREADY OCCURRED. MOST DAYTIME HIGHS WON'T QUITE RECOVER TO THESE LEVELS SO WILL UPDATE FOR SUCH. WEAK OVERALL COOL ADVECTION TODAY FROM THE NORTHWEST TODAY AS UPPER RIDGE WEAKENS. OVERCAST SKIES THIS MORNING...ANY VERY LIGHT PRECIP WEAKENING AND MOVING SOUTH. ETA...RUC AND SATELLITE PICTURE TRENDS INDICATE PARTIAL CLEARING DURING THE AFTERNOON...ESPECIALLY NORTH. EXPECT WINDS TO MIX A LITTLE MORE DURING AFTERNOON. SIMONSEN .LONG TERM... FLAT UPPER RIDGE WILL DOMINATE THE FIRST PORTION OF THIS PERIOD...FROM THURSDAY THROUGH SATURDAY. AM EXPECTING A MODIFIED PACIFIC AIRMASS TO DOMINATE DURING THIS PERIOD WITH A CLIPPER BRINGING WINDY CONDITIONS FOR FRIDAY. A PACIFIC SYSTEM DROPPING INTO THE PLAINS SUNDAY SHOULD ALLOW THE ARCTIC TO DROP INTO NE MT. DYNAMICS AND MOISTURE SHOULD BRING SNOW. GFS SOLUTION SEEMS TO HAVE A GOOD HANDLE ON THINGS...WHILE THE ECMWF SOLUTION...ESPECIALLY FOR SUNDAY...LOOKS WARM AND A BIT OUT OF WHACK (BRINGING RAIN FOR E MT). DROPPED POPS FOR SOME PERIODS BETWEEN THU AND SAT AS DOWNSLOPING SEEMED TOO STRONG FOR PRECIPITATION GENERATION TO OCCUR. REST OF INHERITED FORECAST LOOKS GOOD. JAMBA KGGW BCE /038 015/015 005/031 8200200 JEEJ 017/035 020/040 020/034 007/020 010/ 76033000333 KGDV BEE /040 015/018 004/033 8200200 JEEJ 020/036 020/040 019/035 014/022 012/ 76033000333 .GGW...NONE. mt NORTHEAST MONTANA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 915 AM MST MON JAN 27 2003 .SHORT TERM...PACIFIC COOL FRONT MIXED OUT ALL AREAS INTO THE 40S OVERNIGHT...SO CALENDAR DAY HIGHS HAVE ALREADY OCCURRED. MOST DAYTIME HIGHS WON'T QUITE RECOVER TO THESE LEVELS SO WILL UPDATE FOR SUCH. WEAK OVERALL COOL ADVECTION TODAY FROM THE NORTHWEST TODAY AS UPPER RIDGE WEAKENS. OVERCAST SKIES THIS MORNING...ANY VERY LIGHT PRECIP WEAKENING AND MOVING SOUTH. ETA...RUC AND SATELLITE PICTURE TRENDS INDICATE PARTIAL CLEARING DURING THE AFTERNOON...ESPECIALLY NORTH. EXPECT WINDS TO MIX A LITTLE MORE DURING AFTERNOON. SIMONSEN .LONG TERM... FLAT UPPER RIDGE WILL DOMINATE THE FIRST PORTION OF THIS PERIOD...FROM THURSDAY THROUGH SATURDAY. AM EXPECTING A MODIFIED PACIFIC AIRMASS TO DOMINATE DURING THIS PERIOD WITH A CLIPPER BRINGING WINDY CONDITIONS FOR FRIDAY. A PACIFIC SYSTEM DROPPING INTO THE PLAINS SUNDAY SHOULD ALLOW THE ARCTIC TO DROP INTO NE MT. DYNAMICS AND MOISTURE SHOULD BRING SNOW. GFS SOLUTION SEEMS TO HAVE A GOOD HANDLE ON THINGS...WHILE THE ECMWF SOLUTION...ESPECIALLY FOR SUNDAY...LOOKS WARM AND A BIT OUT OF WHACK (BRINGING RAIN FOR E MT). DROPPED POPS FOR SOME PERIODS BETWEEN THU AND SAT AS DOWNSLOPING SEEMED TOO STRONG FOR PRECIPITATION GENERATION TO OCCUR. REST OF INHERITED FORECAST LOOKS GOOD. JAMBA KGGW BCE /044 015/015 005/031 8600200 JEEJ 017/035 020/040 020/034 007/020 010/ 76033000333 KGDV BEE /046 015/018 004/033 8600200 JEEJ 020/036 020/040 019/035 014/022 012/ 76033000333 .GGW...NONE. mt AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE CLEVELAND OH 855 PM EST MON JAN 27 2003 WL UPDATE FCST MOSTLY FOR TIMING AND COSMETIC CHANGES. INITIAL BATCH OF WAA/ISENTROPIC LIFT CROSSING FCST AREA AND STRUGGLING TO MOISTEN LWR LYRS. DEWPOINTS STILL NR OR BLO ZERO. COULD BE A FEW PATCHES OF LGT SNOW/FLURRIES. NEXT WAVE STARTING TO WORK ACRS MIDWEST. 18Z ETA SHOWS SNOW DVLPNG TWRD DAYBREAK ESP ACRS W PART OF FCST AREA AND WL INDICATE SUCH TIMING IN FCST. LATEST RUC DOES NOT SEEM TO BE CATCHING DVLPNG SYSTEM OVR MIDWEST AND LWR LAKES VERY WELL SINCE CURRENT MOISTURE OR PCPN NOT DEPICTED. NOT SURE EXACTLY WHERE BEST UVV WL DVLP TUES AS WAVE MOVS EWRD WITH UPR DIFFLUENCE AND FRONTOGENISIS....PROB JUST S OF TURNPIKE IF MODELS ARE CORRECT...BUT WL WAIT TO ISSUE ADVISORY SINCE SNOW OUTSIDE OF THIS ZONE WL BE LIGHTER. TEMPS SHUD GEN RISE OVNGT WITH S WIND AND CLDS/PCPN AND WL CONT WITH RISING TEMP TREND IN CURRENT FCST. UPDATE ABT 930 PM. .CLE... OH...NONE. PA...NONE. KOSARIK oh AREA FORECAST DISCUSSION FOR WESTERN SD AND NORTHEASTERN WY NATIONAL WEATHER SERVICE RAPID CITY SD 730 PM MST MON JAN 27 2003 00Z KUNR SOUNDING SHOWED WET BULB ZERO AROUND 3500FT AGL/6500 MSL. THIS WILL BE KEY TO TONIGHT/S FORECAST AS SHORTWAVE OVER WESTERN MT PER WATER VAPOUR RACES EAST. PLENTY OF MOISTURE AVAILABLE PER IR AND LATEST KUDX RADAR RETURNS. 00Z RUC INDICATES TURNOVER OCCURRING BETWEEN 06Z-12Z FROM NORTH TO SOUTH ACROSS CWA. PREVIOUS ZONE UPDATE ALREADY ADDRESSED THIS WITH HIGHER LOWS AND SLIGHTLY SLOWER TURN OVER. 00Z RUC ALSO FURTHER NORTH WITH PRECIPITATION...IN LINE WITH 18Z GFS. WILL BE MONITORING CONDITIONS CLOSELY AND UPDATE AS NEEDED TONIGHT. GIVEN WE USUALLY SEE SN TURNOVER FASTER THAN MODELS INDICATE...WILL CONTINUE CURRENT HEADLINES. .UNR...WINT WX ADVY TNGT FOR PORTIONS NERN WY AND THE SOUTHERN BLACK HILLS. $$ HELGESON sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 315 PM CST MON JAN 27 2003 ...NEAR TERM... NUMEROUS LITTLE DETAILS TO KEEP TRACK OF IN THE NEAR TERM. FIRST IS THE PCPN CHCS TONIGHT ACROSS THE SW...FOG PSBL IN THE JAMES RVR VALLEY...AND PCPN CHCS TUESDAY NIGHT. FOR TONIGHT...MODELS ARE A BIT FURTHER SOUTH WITH 7H WAVE/OMEGA FIELDS ACROSS OUR SW CWA. THE GFS HAS WASHED OUT 7H THETA-E FORCING...WHILE SOME WEAK LIFT STILL NOTED IN THE ETA...AS WELL AS SOME MINOR WIND FIELD CONVERGENCE AT 7H. CURRENTLY KABR GETTING WIDESPREAD ECHOS ACROSS NW CWA...MOST LIKELY ASSOCIATED WITH 7H FROTOGENESIS TAKING PLACE. HOWEVER...KMBG ONLY REPORTING SCT MID CLOUDS. THIS FRONTO FORCING IS PROGGED TO DROP S THIS EVENING...EXITING CWA BY 06Z TUESDAY. WITH TEMPS RUNNING WELL ABOVE FREEZING THIS AREA...AND DWPTS ALSO ABOVE FREEZING...CONFIDENT THAT IF ANY PCPN FALLS...WILL BE IN LIQUID FORM...SO JUST MENTIONED SPRINKLES FOR KPIR AREA THIS EVENING. ATTENTION THEN TURNS TO FOG CHCS. JAMES RIVER VALLEY AREA STILL EXPERIENCING S WINDS...EVEN THO SFC FRONT HAS PASSED THROUGH AREA. T/TD SPREADS ON ORDER OF 5 DEGREES OR SO. RUC/LAMP DATA STILL SHOW LOCAL WINDS TURNING MORE WESTERLY...AIDING IN DRYING OUT LO LEVELS. LOOKING UPSTREAM...NO REAL DRY AIR IN PLACE WITH MOST OF NODAK HAVING DWPTS IN THE LOW-MID 30S. WILL INSERT SOME PATCHY FOG IN THE FOG PRONE JAMES RIVER VALLEY. NEXT IRRITATION IS TEMPS. IF LOW CLOUDS DEVELOP AND FOG...FEEL THAT OVERNIGHT LOWS WILL HANG INTO THE MID 20S. HAVE TRENDED LOWS OVERNIGHT HIGHER THAN GUIDANCE VALUES. TUESDAY IS MORE OF A DAY INBETWEEN SYSTEMS WITH LIGHT N/NW FLOW AT SFC. HIGH PRESSURE NOSES DOWN INTO I-29 CORRIDOR BY LATE IN DAY AS WEAK SFC SYSTEM TRIES TO SPIN UP ACROSS WRN SD. THIS WILL ALLOW WINDS TO TURN TO THE S/SE ACROSS SWRN CWA. WITH CAA TAKING PLACE ALL LEVELS...TEMPS WILL BE MORE IN LINE WITH NORMAL FOR END OF JANUARY. TUESDAY NIGHT...WEAK SFC LOW CONTS TO FORM WHILE UPPER DISTURBANCES DROP SOUTH IN NW FLOW. MODELS SHOWING BAND OF LIGHT SNOW DEVELOPING ACROSS NC SODAK IN THE EVENING...MOVING QUICKLY TO THE SOUTHEAST OVERNIGHT. MODELS REMAIN IN SOME DISAGREEMENT ON LOCATION OF SNOW BAND...SO HAVE PAINTED WITH A RATHER BROAD BRUSH TUESDAY NIGHT FOR LIGHT SNOW. WITH ANTICIPATED CLOUDS AND PCPN OCCURRING...HAVE GONE ABOVE GUIDANCE LOW TUESDAY NIGHT ACROSS THE EAST. FOR WEDNESDAY...STRONG POLAR HIGH DROPS INTO CWA...HELPING TO DRY OUT ATMOS. MODELS CONT TO HANG ONTO LIGHT SNOW THROUGH DAY...BUT THIS APPEARS TO BE OVERDONE. WITH HIGH PRESSURE BUILDING IN AND SUBSIDENCE NOTED AT 7H AND 5H...HAVE GONE WITH DRY FCST FOR WEDNESDAY WITH COOLISH TEMPS. ...LONG TERM... COLD AIR BEGINS TO RETREAT EAST OF CWA FOR WEDNESDAY NIGHT WITH 850 HPA TEMPERATURES ONCE AGAIN RISING ABOVE ZERO ACROSS THE SOUTHWEST. LOW AND MID LEVEL SPECIFIC HUMIDITIES ALSO ON THE RISE WEDNESDAY NIGHT AS MID LEVEL RIDGE CONTINUES TO DAMPEN WITH PACIFIC SHORT WAVES PROGRESSING THROUGH THE LONGWAVE RIDGE. FOR THURSDAY...MODELS HAVE BEEN CONSISTENT WITH ANOTHER SHORT WAVE PUSHING INTO CWA DURING THURSDAY AFTERNOON. Q-VECTOR DIAGNOSTICS NOT OVERLY IMPRESSIVE IN LOW AND MID LEVELS...BUT WITH AFOREMENTIONED LOW LEVEL MOISTURE INCREASES DURING THURSDAY MORNING IN ADVANCE OF THIS SHORT WAVE...WILL NOT REMOVE LIGHT SNOW MENTION FROM CURRENT FORECAST. FRONTAL PASSAGE ASSOCIATED WITH THIS WAVE THURSDAY NIGHT...BUT COLD ADVECTION IS FAIRLY WEAK WITH TRUE ARCTIC AIR CONFINED MORE TO HUDSON BAY REGION. FRIDAY SHOULD BE PARTLY CLOUDY EARLY BUT THEN WITH INCREASING CLOUDS BY LATE AFTERNOON. LATEST GFS RUN IS TOWARD FASTER SHORT WAVE RIDING ALONG US/CANADIAN BORDER WHICH IS NOW MORE INLINE WITH 00Z CANADIAN TIMING. DECENT JET DYNAMICS ALSO APPEAR TO BE MAXIMIZED ACROSS NORTHERN CWA. MODELS ALSO IN GOOD AGREEMENT IN SHOWING SOME STRONG WARM ADVECTION WITH WARM FRONTAL PASSAGE FRIDAY EVENING. WITH EXPECTED ISENTROPIC LIFT AND JET DYNAMICS WILL INCLUDE CHANCE FOR SNOW ACROSS NORTHERN CWA FRIDAY NIGHT. CONFIDENCE DIMINISHES BY SATURDAY AND SUNDAY. GFS HAS BEEN CONSISTENT IN ADVERTISING ANOTHER UPPER WAVE HEADING INTO THE ROCKIES ON SATURDAY AFTERNOON...BUT LATEST TRENDS HAVE BEEN TO DIG WAVE FURTHER SOUTH WITH MORE AMPLITUDE. CANADIAN IS LESS AMPLIFIED WITH EASTERN PACIFIC/WESTERN US RIDGE AND SHOWS WEAKER MORE PROGRESSIVE SHORT WAVE MOVING INTO THE ROCKIES. NCEP ENSEMBLE MEMBERS DO SUGGEST THAT OPERATIONAL GFS RUN IS MAYBE TOO AMPLIFIED WITH THIS SHORT WAVE AS IT DIVES INTO CENTRAL PLAINS. BUT EVEN WITH THIS HEDGE TOWARD WEAKER CANADIAN WILL STILL INCLUDE CHANCE OF SNOW IN GRIDS FROM SATURDAY NIGHT TO SUNDAY AS MODEL ENSEMBLE MEANS AT LEAST IN AGREEMENT OF SHORT WAVE TO AFFECT DAKOTAS. BY MONDAY UPPER RIDGE AMPLIFIES ACROSS EASTERN PACIFIC WHICH PLACES CWA IN A DRY NORTHWEST FLOW PATTERN FOR THE BEGINNING OF THE WEEK WITH COOLER TEMPERATURES. .ABR...NONE. HINTZ/MARSILI sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 1133 AM EST MON JAN 27 2003 HAVE OPTED TO UPDATE ZFP TO MAKE SOME MINOR CHANGES TO MOSTLY THE FIRST PERIOD AND TO DROP WIND CHILL ADVISORY ACRS SRN VT. HI PRESS RIDGE TO MOVE ACRS THE FA FROM THE WEST TODAY AND TONITE. UPR TROF TO MOVE ACRS THE FA TODAY AS WELL. S/W TO MOVE DOWN ACRS THE GREAT LKS REGION TONITE AND INTO THE FA FROM THE NW LATE TONITE. 12Z 20KM "DEVELOPMENT" RUC SHOWS TEMPS TO BE IN THE TEENS BELOW ZERO THRU THE SINGLE NUMBERS TODAY WITH W-NW SFC WINDS AT 5-20 KTS. T1MAX TEMPS ARE BASICALLY ZERO TO +10F TODAY. FEW MINOR TWEAKS TO FIRST PERIOD WINDS/TEMPS BASED ON THIS DATA. BASED ON EXPECTED WINDS/TEMPS FOR THE REST OF TODAY...WIND CHILL TEMPS OF -10F TO -25F ARE EXPECTED ACRS THE FA TODAY. SRN VT WILL MOST LIKELY NOT SEE WIND CHILL READINGS BLO -15F. THEREFORE...HAVE DROPPED WIND CHILL ADVISORY ACRS SRN VT AND WILL KEEP WIND CHILL ADVISORIES AS IS ACRS THE REST OF THE FA. WILL MOST LIKELY BE ABLE TO KILL ALL HEADLINES WITH THE AFTERNOON PACKAGE. LOW-LVLS TO BE DRY TODAY ACRS THE FA. VIS SAT PIX SHOW VERY LITTLE IN THE WAY OF CLDS ACRS THE FA ATTM. H85 CAA TO TAKE PLACE ACRS THE FA TODAY AND TONITE. SOME LOW-LVL MSTR ADVECTION TO TAKE PLACE ACRS THE FA LATE TONITE. BEST LOW-LVL MSTR TO BE LOCATED TO THE WEST OF THE FA TONITE THOUGH. SOME MID-LVL MSTR TO AFFECT THE WRN ZONES BY LATE TONITE. NO OTHER SIGNIFICANT CHANGES TO THE GOING ZFP NEEDED ATTM. WRK ZONES...FINAL ZFP AND WSW ALREADY ISSUED. LATER... .BTV...WIND CHILL ADVISORY FOR THE REST OF TODAY FOR NYZ026>031-034- 035-VTZ001>010. MURRAY vt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 320 AM CST MON JAN 27 2003 ...TONIGHT THROUGH THURSDAY... MAIN FORECAST CHALLENGE IS THE PRECIPITATION AND TYPE LATE TONIGHT AND TUESDAY. SOUTHWEST WINDS HAVE REACHED ADVISORY CRITERIA ACROSS THE OPEN AREAS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA. THESE HAVE BEEN THE RESULT OF THE PRESSURE GRADIENT FORCE IN THE AREA AT THE SURFACE AND SUPPORTED BY THE 40-50 KNOT WINDS AT 850 MB. KARX-88D DETECTS NO SNOW ACROSS THE FORECAST AREA. THE EARLIER ACTIVITY EXITED THE FORECAST AREA BY 100 PM. WARM ADVECTION ACROSS THE FORECAST AREA HAS PUSHED READINGS INTO THE 20S ACROSS THE SOUTHWESTERN 2/3RDS OF THE FORECAST AREA. 12Z CYCLE OF THE RUC/ETA/GFS ARE IN REASONABLE AGREEMENT. NO MAJOR INITIALIZATION ERRORS NOTED. WINDS SHOULD DECREASE THIS EVENING DUE TO LOSS OF MIXING. WILL ALLOW WIND ADVISORY TO EXPIRE. FORECAST TEMPERATURES TONIGHT ARE A REAL TASK TONIGHT. WARM AIR /TEMPERATURES NEARING 40 OVER WESTERN IOWA AND MINNESOTA/ SURGING INTO THE FORECAST AREA FROM THE SOUTHWEST SHOULD CONTINUE...BUT HOW LONG. OVERNIGHT...THE PRESSURE GRADIENT DECREASES ENOUGH TO ALLOW FOR SOME DECOUPLING AND SUBSEQUENT TEMPERATURE FALLS. SO WILL FORECAST RISING TEMPERATURES THIS EVENING UNTIL GRADIENT DECREASES. THEN WILL ALLOW FOR A BIT OF A DECREASE TOWARD MORNING. NEXT DISTURBANCE MOVES THROUGH THE REGION TUESDAY. ETA CONTINUES TO BE VERY CONSISTENT WITH ITS PREVIOUS RUNS. THE GFS IS FURTHER SOUTH THIS RUN AND HAS COME INTO ALIGNMENT WITH THE ETA. THE 10KM RUC EXTENSION INITIATES PRECIPITATION OVER THE CENTER OF THE FORECAST AREA THEN MOVES IT SOUTH. THIS IS AN INTERESTING FORECAST...BUT SINCE I CANNOT SEE ANY OF THE OTHER FIELDS /FORCING...ETC/ WILL HAVE TO DISCARD. ETA KEEPS PRECIPITATION OVER THE EXTREME SOUTHERN PART OF THE FORECAST AREA...THEN PUSHES IT SOUTH. FORCING...MAINLY FROM FRONTOGENETIC PROCESSES /QN 700-500 MB/...IS QUITE STRONG IN THIS REGION AS EXPECTED. HOWEVER...THERE IS ANOTHER AREA OF THIS FORCING NORTH EXTENDING FROM KRST-KLSE. THEREFORE...WILL CONTINUE CHANCE OF PRECIPITATION NORTH OF THE MODEL QPF AREA...UP INTO THIS REGION. PRECIPITATION TYPE IS AN ISSUE WITH THIS STORM. BUFR SOUNDINGS SUGGEST AN INITIAL FREEZING RAIN EVENT ALONG AND SOUTH OF AN OSAGE IOWA TO RICHLAND CENTER APPROXIMATION...WHERE WARM LAYER TEMPERATURES ARE GREATER THAN 3C. THE WARM LAYER TEMPERATURE DECREASES THROUGHOUT THE MORNING AS COLD AIR IS ADVECTED IN FROM THE NORTH FROM PASSING LOW TO THE SOUTH. SOIL TEMPERATURES REMAIN QUITE LOW AND ANY LIQUID THAT DOES FALL DURING THE MORNING WILL QUICKLY FREEZE. AS A RESULT...WILL ISSUE A WINTER WEATHER ADVISORY FOR THE SOUTHERN TIER OF COUNTIES. SYSTEM EXITS TUESDAY LATE...TAPPING MORE COLD AIR AND ADVECTING IT INTO THE FORECAST AREA. MOS FINALLY AGREES WITH THIS FORECAST THINKING...WITH LOWS IN THE SINGLE DIGITS WEDNESDAY MORNING. THIS SHOULD BE SHORT LIVED AS ANOTHER SYSTEM NEARS THE REGION LATER THIS WEEK...CAUSING MORE WARM ADVECTION. THIS WILL MAINLY OCCUR THURSDAY AND THURSDAY NIGHT. KRC ...THURSDAY NIGHT THROUGH MONDAY... MAIN CONCERN DURING THE FORECAST PERIOD WILL BE TRACK AND TIMING OF STORM SYSTEM SUNDAY AND MONDAY. MODELS IN GOOD AGREEMENT WITH NEXT SHORTWAVE FOR FRIDAY AND SATURDAY...AND THEN BEGIN TO DIVERGE ON TIMING AND TRACK OF SYSTEM SUNDAY AND MONDAY. 12Z GFS RUN CONTINUES TO SHOW WEAK DISTURBANCES EMBEDDED IN WEST/NORTHWEST UPPER LEVEL FLOW MOVING INTO THE UPPER MIDWEST FRIDAY AND SATURDAY. MAIN UPPER LEVEL FORCING WITH THESE FEATURES REMAINS NORTH OF THE FORECAST AREA FRIDAY...WITH WEAK UPPER LEVEL FORCING ACROSS THE SOUTHERN PORTION OF THE FORECAST AREA. WILL REDUCE PRECIPITATION CHANCES ACROSS SOUTHERN ZONES FRIDAY AS A RESULT. 12Z GFS INDICATING SLIGHTLY WARMER 850MB TEMPS ADVECTING IN ACROSS THE REGION FRIDAY AND SATURDAY. WILL RAISE TEMPS A DEGREE OR TWO ACROSS THE AREA FRIDAY AND SATURDAY. 00Z GFS INDICATES A DEEPER AND SLIGHTLY SLOWER MOVEMENT OF UPPER LEVEL TROUGH ACROSS THE CENTRAL U.S. SUNDAY THAN THE PREVIOUS RUN. 00Z AND 12Z GFS IN GOOD AGREEMENT WITH TRACK OF SURFACE LOW INTO SOUTHERN WISCONSIN AT 12Z MONDAY. THIS TRACK LOOKS FAVORABLE FOR HEAVY SNOWS ACROSS THE FORECAST AREA. WILL KEEP CHANCES OF PRECIPITATION SUNDAY AND MONDAY...AND LET LATER FORECAST NARROW DOWN ONSET OF PRECIPITATION. DTJ COORDINATED WITH DVN/DMX/MKX. .LSE...WINTER WEATHER ADVISORY LATE TONIGHT THROUGH TUESDAY MORNING...IAZ018-019. WINTER WEATHER ADVISORY TUESDAY MORNING...IAZ029-030-WIZ061. $$ KRC wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 240 AM CST TUE JAN 28 2003 GOING SHORT TERM FORECAST LOOKING QUITE GOOD, BUT HAVE DELAYED ONSET OF PRECIP IN CENTRAL AND SOUTHERN SECTIONS. ADVISORY WILL REMAIN INTACT MENTIONING TIMING CHANGE. VERY WARM NOSE OF AIR AND STEEPER LAPSE RATES HAVE NOW SPREAD OVER THE STATE. IR IMAGERY SHOWING FLARE UP OF MID LEVEL CLOUDS IN KS APREADING INTO NW MO WHICH MAY BE A SIGN OF THE CONVECTIVE INSTABILITY ALOFT. WE'LL SEE IF IT'S REALIZED LATER TODAY, BUT THAT COULD CERTAINLY PLAY A ROLE IN PRECIP TYPE AND INTENSITY. FOR NOW, THE FZRA THREAT APPEARS MOST LIKELY PER CURRENT SFC WET BULB TEMPS AND WARM NOSE ALOFT PER SOUNDINGS. I HAVE INCLUDED SLEET N SECTIONS AS FORECAST SOUNDINGS WEAKEN THE WARM LAYER, WITH SN AFTER NOON MIXING IN. META CROSS SECTIONS OF EPV/FRONTOGENESIS/AGEO CIRC SHOW NICE MAXIMUM OF LIFT IN DENDRITIC ZONE, BUT JUST ABOVE HIGHEST MOISTURE. META/GFS/CANADIAN ALL CONSISTENT ON QPF, WITH BEST BAND IN THIS OMEGA FIELD. 06Z RUC SHOWING SIMILAR TREND. CURRENT RADAR SHOWS EXPANDING ECHOES IN NW IA INTO SE SD WHICH SHOULD EVOLVE INTO FORECAST PRECIP SHIELD. WILL NOT CHANGE MUCH TO LONG TERM WITH GFS STILL SHOWING WARM ADVECTION/ISENTROPIC LIFT SETTING UP FOR THURSDAY NIGHT PRECIP FORECAST. 00Z CANADIAN ALSO CONSISTENT WITH PREVIOUS RUN AND 00Z/27 GFS. LOW PRESSURE SYSTEM TRACK THROUGH MO/IL SUNDAY INTO MONDAY. NOT ENOUGH EVIDENCE TO CHANGE FORECAST MUCH AT THIS TIME. .DSM...WINTER WEATHER ADVISORY TODAY ALL BUT SOUTHERN TIER OF COUNTIES. KULA ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 222 AM MST TUE JAN 28 2003 FORECAST CHALLENGE IS TEMPS THROUGH THE PERIOD ALONG WITH CHANCES OF PRECIPITATION. FRONTAL PASSAGE AROUND 12Z THIS MORNING WITH A WIND SHIFT TO THE NORTH. ONLY MID LEVEL MOISTURE AVAILABLE AT THE TIME OF MAXIMUM LIFT...SO DRY FORECAST LOOKS GOOD. AROUND 18Z SURFACE PRESSURE RISES ON THE ORDER OF 3 TO 4 MB/3 HOURS AS LOW PRESSURE DEEPENS WELL TO OUR SOUTH. RUC II SHOWS SOME GUSTS OF >25KTS IN THE AFTERNOON IN ALL BUT THE NEBRASKA COUNTIES. MOS WIND GUIDANCE IS ALSO LOWER AT MCK...SO WILL KNOCK THOSE AREAS DOWN TO BREEZY. LOW LEVEL MOISTURE/CLOUDS ARRIVE IN THE AFTERNOON AS WELL...BUT POST FRONTAL SUBSIDENCE AGAIN SQUELCHES PRECIP CHANCES. WILL UNDERCUT GUIDANCE HIGHS A BIT DUE TO CLOUD COVER/CAA BEHIND THE FRONT. SOME PATCHY FOG LOOKS TO BE A POSSIBILITY OVERNIGHT...BUT WILL HOLD OUT OF ZONES FOR NOW. WEDNESDAY...VORT MAX DROPS THROUGH THE NORTHERN PLAINS DURING THE AFTERNOON. ETA IS STRONGER AND FURTHER WEST WITH THE DYNAMICS THAN THE GFS. MAIN COLD SURGE STAYS WELL EAST...BUT SOME COLDER AIR IS BACKDOORED INTO THE NORTHEASTERN THIRD OF THE CWA. EASTERLY UPSLOPE SURFACE FLOW IS ALSO MAXIMIZED IN THAT AREA. ETA POPS ARE AROUND 30 COMPARED TO NIL IN THE GFS. GIVEN THE PROPENSITY FOR BACKDOOR FRONTS TO BE STRONGER THAN MODEL GUIDANCE AS OF LATE...WILL INTRODUCE SLIGHT CHANCE OF PRECIPITATION ACROSS NEBRASKA COUNTIES/YUMA/KS BORDER COUNTIES. PHASE IS PROBLEMATIC. BUFR SOUNDING NEAR MCCOOK SHOWS MOST OF THE COLUMN BELOW FREEZING EXCEPT FOR A VERY SHALLOW LAYER NEAR THE SURFACE. GIVEN THAT LIFT IS UPSLOPE DRIVEN...AT THIS TIME EXPECT FREEZING DRIZZLE/LIGHT FREEZING RAIN AT THE ONSET CHANGING TO FREEZING DRIZZLE/FLURRIES AS COLDER AIR WORKS IN LATER IN THE AFTERNOON. THURSDAY...ANOTHER SHORTWAVE...THIS TIME OF PACIFIC ORIGIN...COMES DOWN IN THE NORTHWEST FLOW. LEFT FRONT QUADRANT OF JET ALSO PROVIDES GOOD DIVERGENCE ALOFT. PROBLEM IS LACK OF MOISTURE IN THE LOW LEVELS. SURFACE LEE TROUGH IN PLACE LOOKS TO PROVIDE SOUTHWEST SURFACE WIND/DRY SLOT AHEAD OF THE SYSTEM. LEE TROUGH PUSHES EAST LATE IN THE DAY. SOME LIMITED MOISTURE AT THAT TIME BUT NORTHWEST SURFACE FLOW BEHIND THE TROUGH IS NOT SUPPORTIVE OF PRECIPITATION. GFS QPF IS VERY LIGHT...EXTENDED ETA IS DRY. DO NOT FEEL PRECIPITATION CHANCES ARE WARRANTED. NO CHANGES TO EXTENDED. .GLD...NONE. $$ JDK ks AREA FORECAST DISCUSSION...CORRECTED DATE IN HEADER NATIONAL WEATHER SERVICE MARQUETTE MI 445 AM EST TUE JAN 28 2003 MAIN FCST CONCERNS ARE LES POTENTIAL LATER TODAY THROUGH WED. WV IMAGERY AND RUC ANALYSIS INDICATED RELATIVELY ZONAL PATTERN WITH WNW MID/UPR LVL FLOW THROUGH THE WRN LAKES BENEATH NORTH CNTRL CANADA POLAR VORTEX. ONE WEAK SHRTWV WAS LOCATED OVER NRN ONTARIO WHILE NEXT SIGNFICANT UPSTREAM SHRTWV WAS LOCATED NRN ALBERTA. AT THE SFC...A TROF EXTENDED FROM NRN ONTARIO TOWARD WRN LK SUPERIOR WITH A WARM FRONT STRETCHING SOUTH TOWARD SE MN. ANOTHER ARCTIC HI PRES LURKED OVER WEST CNTRL CANADA BEHIND A COLD FRONT WHICH HAD MOVED THROUGH NRN MN. KMQT 88D AND OBS OVER NRN UPR MI INDICATED SOME FLURRIES LINGERING IN WAA/ISENTROPIC LIFT REGIME. SO FAR...LOW LVL TEMP PRFL IS COLD ENOUGH WITH ENOUGH MOISTURE NEAR -10C ISOTHERM TO MINIMIZE -FZDZ THREAT. UPSTREAM OVER NRN WI AND SRN UPR MI...MODEST LOW LVL MOISTURE WITH DEWPOINTS DEPRESSIONS OF 4-7 F ALSO WERE NOT CONDUCIVE TO FREEZING PCPN. SINCE ETA/GFS WERE IN REASONABLE AGREEMENT WITH STRENGTH AND PROGRESSION OF COLD AIR ACRS LK SUPERIOR INTO UPR MI THROUGH WED AND SYNOPTIC SCALE FEATURES...ETA WAS USED FOR DETAILS REGARDING LES. TODAY...LINGERING FLURRIES SHOULD END EARLY AS 280K ISENTROPIC LIFT SLIDES OFF TO THE EAST. AS SFC TROF MOVES TO THE EAST...COLD FRONT WILL MOVE THROUGH WITH ARCTIC HI PRES AND COLDER AIR FILTERING INTO THE AREA. H8 TEMPS FCST TO DROP TO -15C NEAR THE KEWEENAW BY 18Z AND NORTH CNTRL UPR MI BY 21Z. BY 00Z H8 TEMPS FALL TO NEAR -18C. 06Z ETA AND RUC WERE A BIT SLOWER WITH THE COLD AIR. LOW LVL CONVERGENCE NEAR THE FRONT MAY SUPPORT SOME INCREASE IN SNOW SHOWER ACTIVITY BUT WITH MARGINAL INSTABILITY...LITTLE ACCUMULATION EXPECTED TIL COLDER AIR ARRIVES. TONIGHT INTO EARLY WED...WHILE ENOUGH INSTABILITY EXPECTED BY TONIGHT FOR ACCUMULATING LES...INVERSION HGTS REMAIN BTWN 3K-4K FT. GRADUAL VEERING OF LOW LVL WINDS FROM 320 EARLY THIS AFTERNOON TO NEAR 350 BY 06Z/WED WILL ALLOW LES TO SHIFT INTO ERN MARQUETTE COUNTY. HOWEVER RELATIVELY LIGHT CBL FLOW OF 20 KTS AND LAND BREEZE DEVELOPMENT SHOULD ALLOW LK INDUCED TROF DEVELOPMENT AND KEEP BULK OF LES EAST OF MARQUETTE. FCST LOW LVL CONVERGENCE IS GENERALLY VERY WEAK. MAIN EFFECTS (MOISTURE/LIFT) OF SHRTWV MOVING OUT OF WRN CANADA ARE EXPECTED TO REMAIN TO THE SW OF UPR MI. HOWEVER...WITH 06Z ETA DEPICTION OF PROXIMITY OF LIGHT QPF AND TREND TOWARD BETTER QG FORCING AND LIFT WILL MENTION CHANCE OF SNOW SHOWERS OVER SRN UPR MI. A BRIEF BOOST TO LES IS ALSO POSSIBLE WITH THIS FEATURE BUT SHOULD HAVE MINOR IMPACT ON OVERALL ACCUMULATIONS. RELATIVELY SHALLOW COLD AIR AND VERY DRY AIR UPSTREAM WITH SYNOPTIC SCALE ACYC FLOW SHOULD LIMIT SNOWFALL AMOUNTS GENERALLY TO 1-3 INCH AMOUNTS PER 12 HRS WITH SOME LCL 4 INCH AMOUNTS. UNLIKE LES WITH RECENT VERY COLD ARCTIC AIR MASSES TEMPS IN SNOW GROWTH PRFL ARE A BIT MORE FAVORABLE WHICH MAY ALLOW MORE FLUFFY HIGH SNOW/WATER RATIO TYPE SNOW. LATER WED INTO THU...HIGH PRES BUILDS FROM THE NRN PLAINS TOWARD THE LOWER LKS BRINGING BACKING WINDS AND WAA AS THE H8 THERMAL TROF SLIDES EAST OF LK SUPERIOR. WAA INCREASES WED NIGHT WITH TIGHT GRADIENT DEVELOPING AS THE HIGH SINKS TO THE SOUTH. WHILE MOST SFC WINDS SHOULD BE DECOUPLED...ENOUGH MIXING SHOULD DEVELOP FOR STEADY OR SLOWLY RISING TEMPS LATE. TEMPS NEAR GUIDANCE VALUES AND CURRENT FCST VALUES LOOKED REASONABLE. .MQT...HEAVY FREEZING SPRAY WARNING LAKE SUPERIOR. JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 348 AM EST TUE JAN 28 2003 THE MAIN FORECAST CHALLENGE DEALS WITH THE SNOW AMOUNTS LATER THIS AFTERNOON AND THIS EVENING ASSOCIATED WITH THE PASSAGE OF A RIGHT ENTRANCE REGION OF AN UPPER LEVEL JET. THE ETA IS MUCH FURTHER SOUTH WITH THE AXIS OF HEAVIER PRECIPITATION...KEEPING IT SOUTH OF I94. THE AVN IS MUCH FURTHER NORTH. AM LEANING WITH THE AVN SOLUTION...BECAUSE IT VERIFIED MUCH BETTER AT 06Z WITH THE SURFACE LOW OVER CO...HANDLED THE 850 HEIGHTS BETTER AND THE LATEST RUC IS ALSO MUCH FURTHER NORTH WITH THE RIGHT ENTRANCE REGION OF THIS 250 MB JET THAN THE ETA SHOWED. FEEL THAT IT WILL BE CLOSE TO AN ADVISORY EVENT ALONG THE I94 CORRIDOR. THE FLOW OF MOISTURE IS IN PLACE WITH SURFACE DEWPOINTS CLIMBING THROUGH THE CENTRAL PLAINS AND THERE IS SOME PRECIPITATION NOW BREAKING OUT OVER SD. ISENTROPIC SURFACE I290 ON THE RUC ALSO PICKS UP THIS DEVELOPING PRECIPITATION AS WELL. THE SNOW SHOULD MOVE IN DURING THE AFTERNOON. SO WILL GO WITH A 2 TO 4 INCH SNOWFALL FORECAST FROM 18Z TO 06Z ALONG THE I94 CORRIDOR...AND DROP VALUES THE FURTHER NORTH YOU GO. AM EXPECTING LITTLE OR NO ACCUMULATION BY THE TIME YOU GET TO ROUTE 10. TODAY...ANY FREEZING DRIZZLE SHOULD BE PATCHY. WILL BE WATCHING OBS AND RADAR TRENDS...AND MAY TAKE IT OUT BEFORE 0430 AM ZONE ISSUANCE. CURRENTLY NONE REPORTED IN THE AREA. STEADIER SNOW SHOULD MOVE IN FROM THE WEST THIS AFTERNOON...AS THE MOISTURE DEEPENS UP AND BETTER LIFT ARRIVES. THE HIGHEST PROBABILITY FOR SNOW WILL BE ALONG THE I94 CORRIDOR. TONIGHT THE SNOW WILL PULL AWAY AROUND 06Z...AS DRIER AND COLDER AIR PUSHES IN FROM THE NORTHWEST. LAKE EFFECT DOES NOT LOOK TO FAVORABLE TONIGHT BEHIND THE DEPARTING WAVE. A BETTER POTENTIAL FOR LAKE EFFECT EXISTS ON WEDNESDAY BUT PROBABILITIES ARE CONDITIONAL AND THE LOW LEVEL FLOW IS NOT VERY CONVERGENT. LITTLE OR NO ACCUMULATION IS EXPECTED. INVERSION HEIGHT COME WAY DOWN WEDNESDAY NIGHT AND THIS SHOULD LEAD TO SKIES SCATTERING OUT. A COLD NIGHT IS EXPECTED AS THE SURFACE RIDGE DOMINATES. WITH FRESH SNOWFALL...JXN TO LAN MAY ONCE AGAIN FALL BELOW ZERO. MJS EXTENDED FORECAST DISCUSSION... THE SFC HIGH PRESSURE RIDGE WILL MOVE EAST THURSDAY SETTING UP SOUTHERLY RETURN FLOW. WE'LL CONTINUE TO GO WITH MOSTLY CLOUDY FORECAST WORDING ALTHOUGH WE WOULDN'T BE SURPRISED TO SEE A FEW BREAKS IN CLOUD COVER EARLY THURSDAY. A SFC TROUGH AND UPPER SHORTWAVE WILL SWING IN FRIDAY... SO WE'LL CONTINUE TO CARRY A CHANCE OF LIGHT SNOW WITH THOSE FEATURES. WE'LL GO WITH AN OPTIMISTIC AND DRY FORECAST SATURDAY AS WEAK RIDGING BUILDS IN AT THE SFC AND ALOFT. BY SUNDAY A FAIRLY STRONG LOW PRESSURE SYSTEM WILL DEVELOP OUT OVER THE PLAINS STATES AS STRONG UPPER LEVEL ENERGY MOVES THROUGH THE ROCKIES. OUT AHEAD OF THAT SYSTEM WE EXPECT THE RIDGE TO BUILD OVER OUR REGION AND SW FLOW TO BECOME STRONGER... SO IT WILL DEFINITELY BECOME MILDER. MOISTURE WILL QUICKLY INCREASE TOO AND WE'LL CONTINUE TO CARRY A CHANCE FOR RAIN. IF ECMWF GUIDANCE IS CORRECT THERE IS ABSOLUTELY NO QUESTION P-TYPE WOULD BE STRAIGHT RAIN. HOWEVER... 00Z CANADIAN GUIDANCE WANTS TO TAKE THIS LOW ON A MUCH FURTHER SOUTH TRACK... SO THIS WILL NEED TO BE WATCHED. RIGHT NOW TO MAINTAIN CONTINUITY AND CONSISTENCY WE'RE GOING WITH ECMWF AS MODEL OF CHOICE. WE'LL HAVE A CHANCE OF RAIN OR SNOW MONDAY. ANY RAIN WOULD LINGER INTO THE MORNING BEFORE PCPN QUICKLY CHANGES TO SNOW AS THE LOW MOVES EAST AND CAA KICKS IN. LAURENS .GRR...NONE. mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 610 AM CST TUE JAN 28 2003 AVIATION DISCUSSION FOR THE 12 UTC TAFS... THE ACARS SOUNDING AT ROCKFORD STILL SHOWS RELATIVELY DRY AIR AND AN INVERSION ABOUT 850 MB. THERE IS WARM AIR ADVECTION AT 850 MB AND THE AVN AND ETA MODELS KEEP THE ADVECTION THROUGH 18 UTC. WILL FORECAST FREEZING RAIN THROUGH 17 UTC. THE MESO ETA AND RUC MODELS FORECAST MAXIMUM VERTICAL VELOCITY ABOUT 17 TO 21 UTC. WILL FORECAST THE LOWEST CEILINGS AND SNOW AT THAT TIME. CEILINGS ABOUT 600 FEET TO 1500 FEET AND VISIBILITY DOWN TO 1/2 MILE. THE COLDER AIR COMES IN ABOUT 19 TO 20 UTC AND CHANGE THE PRECIPITATION WILL BE SNOW. THIS SYSTEM IS A WEAK WARM FRONT WITH MOST OF THE FORCING FROM DIVERGENCE FROM A JET STREAM AND ISENTROPIC OVERRUNNING. THE COLDEST AIR WILL NOT ARRIVE UNTIL WEDNESDAY. RADAR IS SHOWING INCREASING PRECIPITATION ALOFT. THE PRECIPITATION WILL EVENTUALLY REACH THE GROUND AS THE MOISTURE CONTENT OF THE AIR RISES. DEWPOINTS HAVE BEEN INCREASING IN THE TAFS AREA DURING THE LAST 6 HOURS. WILL FORECAST A SLOW END THE SNOW LATE TONIGHT AS SUBSIDENCE WILL MOVE INTO THE AREA. WHW PUBLIC DISCUSSION FOR 4 AM ZONES... COMPLEX WEATHER FORECAST THIS MORNING WITH ONE SHORT WAVE PUSHING THROUGH EASTERN ONTARIO WITH IT ASSOCIATED COLD FRONT TRAILING THROUGH UPPER MIDWEST...AND ANOTHER WAVE MOVING INTO THE PLAINS FROM THE NORTHERN ROCKIES. STRONG BAROCLINIC ZONE ACROSS NEB AND IA AHEAD OF SURFACE LOW DEVELOPING OVER HIGH PLAINS OF ERN CO/WRN KS. PRECIPITATION CURRENTLY BREAKING OUT ACROSS SOUTH DAKOTA NORTHEAST NEB AND NW IA. THIS AREA OF PRECIP FORECAST TO EXPAND QUICKLY EASTWARD TODAY AS WAVE APPROACHES AND FRONTOGENETIC FORCING INCREASES...AND AREA COMES UNDER RIGHT ENTRANCE TO 125 KNOT UPPER JET OVER THE GREAT LAKES. ETA APPEARS TO BE A LITTLE TOO QUICK IN GENERATING PRECIP HERE JUST AFTER 12Z...AND PREFER AVN IDEA OF DEVELOPMENT DURING THE MORNING. ETA/GFS ARE FAIRLY SIMILAR IN DEVELOPING A FEW TENTHS OF AN INCH QPF ACROSS NRN IL AND NW IND...THOUGH SIGNIFICANT FORECAST QUESTION IS THAT OF PRECIP TYPE. FORECAST SOUNDINGS FROM ETA INITIALLY SHOW MAX WARM LAYER TEMPS AROUND 0 NORTH TO +1 SOUTH. THIS WOULD SUPPORT SOME SLEET AT ONSET...THEN EVAPORATIVE COOLING CHANGING PRECIP TO SNOW FROM NORTH TO SOUTH. HOWEVER...ACARS SOUNDINGS OUT OF RFD THIS MORNING SHOWING TEMPS BETWEEN +4 AND +6 ABOVE INVERSION AT ABOUT 840 MB. THIS WOULD SUGGEST A MIX OF FREEZING RAIN AND SLEET AT ONSET OF PRECIP. LOOKING AT AVN 295K ISENTROPIC FORECASTS...SATURATION OCCURS NORTHERN PORTIONS OF THE FA THIS MORNING...WITH 3 TO 4 G/KG AVAILABLE WHERE CHANGE OVER TO SNOW WILL BE EARLIEST. THUS AM INCLINED TO BUMP AMOUNTS TO 2-4 INCHES NORTH AND CONTINUE WITH LESSOR AMOUNTS TO SOUTH WHERE ARRIVAL AND CHANGEOVER TO BE LATER AND PRECIP LIKELY OF SHORTER DURATION. THIS BELOW 4 INCH ADVISORY CRITERIA. WITH QUESTIONS ABOUT FREEZING RAIN VS. SLEET AND SPEED OF CHANGE OVER WILL LET DAY SHIFT MONITOR ANY FREEZING RAIN PROBLEMS FOR WINTER WEATHER ADVISORY IF NECESSARY. WITH ALL THE FOCUS ON THE NEAR TERM THIS MORNING WILL NOT MAKE TOO MANY CHANGES TO REMAINDER OF FORECAST. SECOND WEAKER SHORT WAVE MOVES THROUGH WEDNESDAY MORNING...BUT ONLY SOME CLOUDS EXPECTED AS AIRMASS IS DRY AND FORCING RATHER WEAK. SURFACE HIGH PRESSURE THEN BUILDS IN WEDNESDAY NIGHT WITH CLEAR SKIES AND LIGHT WINDS...AND ANY SNOW COVER...LEADING TO COLD TEMPS. LOWERED MINS WED NIGHT SIGNIFICANTLY FROM GOING FORECAST IN LINE WITH GUIDANCE. SURFAC RIDGE MOVES EAST THURSDAY...WITH CHANCE AT SOME LIGHT WAA SNOW THURSDAY NIGHT. NEW GFS BRINGS MORE AMPLIFIED WAVE ACROSS THE AREA FRIDAY AND FRIDAY NIGHT...WITH ANOTHER CHANCE OF SNOW. THANKS FOR COORD IWX...DVN...ILX. .CHI...NONE RATZER il AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GOODLAND KS 907 AM MST TUE JAN 28 2003 COLD FRONT HAS PUSHED THROUGH THE ENTIRE CWA WITH TEMPERATURES UNDER ABUNDANT CLOUD COVER IN THE 40 TO 45 DEGREE RANGE. WINDS ALSO PICKING UP WITH WINDY CONDITIONS ACROSS MUCH OF THE AREA. FOR THE UPDATE...RUC HANDLING TEMPS AND CLOUD COVER THE BEST WITH STRATUS CURRENTLY OVER NORTHEAST COLORADO PUSHING SOUTH. WILL GO CLOUDY ACROSS THE BOARD AND LOWER TEMPS SUBSTANCIALLY FROM PREVIUS FORECAST GIVEN CLOUDS AND CURRENT TEMPS. WILL ALSO BUMP ALL ZONES TO WINDY CATEGORY THROUGH AFTERNOON BEFORE SETTLING DOWN TOWARD 00Z. NO OTHER CHANGES MADE. .GLD...NONE. $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1117 AM EST TUE JAN 28 2003 KGRR-88D AND REGIONAL MOSAIC OF SURROUNDING 88-D/S HAS SHOWN AN INCREASE IN PCPN ACROSS THE CWA...AS EXPECTED. 12Z RAOBS SHOW SOME DRY AIR IN PLACE NEAR 850 MB BUT THE PROFILE IS STILL FAIRLY MOIST SURROUNDING THAT AREA. GIVEN WHERE PCPN IS CURRENTLY FALLING, WE'LL BOOST POPS IN THE NORTH INTO THE LIKELY CATEGORY AND MENTION ACCUMS AROUND AN INCH POSSIBLE. THE PCPN ACROSS THE NORTH IS BEING AIDED BY THE RRQ OF THE UPR JET. AVN IS STILL THE WETTEST SHOWING OVER A TENTH OF AN INCH OF PCPN WHILE THE RUC/ETA SHOW ABOUT HALF OF THAT. RADARS TO THE WEST OVER IA/NE SUGGEST THAT A BAND OF HEAVIER PCPN EXISTS IN THE SRN PORTION OF THE OVERALL PCPN FIELD WHICH WOULD STILL PLACE HIGHER TOTALS ACROSS THE SRN CWA...WHERE THEY CURRENTLY ARE. WILL LEAVE THE SRN PORTION OF THE FCST AS IS. 93 .GRR...NONE. mi SOUTHEAST MICHIGAN AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1100 AM EST TUE JAN 28 2003 12Z RAOBS/WATER VAPOR LOOP SHOW A FAST ZONAL FLOW ACROSS THE NORTHERN CONUS...WITH SHORTWAVE OVER THE DAKOTAS. 120KT JET OBSERVED AT 300MB FROM THE DAKOTAS THROUGH THE GREAT LAKES. SURFACE ANALYSIS SHOWS HIGH PRESSURE ALONG THE ATLANTIC COAST. COLD FRONT ACROSS THE WESTERN GREAT LAKES...FROM LOW OVER NORTHERN ONTARIO TO DEVELOPING LOW OVER THE SOUTHERN PLAINS. REGIONAL RADARS/SURFACE OBSERVATIONS SHOW ECHOS FROM WESTERN LOWER MICHIGAN BACK THROUGH SOUTHERN MINNESOTA/IOWA...BUT WITH SURFACE REPORTS OF PRECIP CONFINED MAINLY FROM WISCONSIN WESTWARD. UPDATE CONCERN REVOLVES AROUND SNOW CHANCES/ACCUMULATIONS FOR THIS AFTERNOON/EVENING. WEAK LOW-LEVEL WARM ADVECTION AROUND THE 290K ISENTROPIC SURFACE COMBINED WITH 700MB FRONTOGENESIS FARTHER NORTH...TOPPED OFF WITH 500MB/300MB DIVERGENCE IN RIGHT-ENTRANCES OF JETS...LEADING TO THE RATHER WIDESPREAD AREA OF REFLECTIVITIES FROM MINNESOTA/IOWA INTO LOWER MICHIGAN. UPPER JET CURRENTLY FOCUSED BACK ACROSS MINNESOTA/WISCONSIN...PROVIDING THE GREATER NORTHWARD EXTENT TO PRECIP. AS THESE FEATURES MOVE EASTWARD...EXPECT THIS SNOW TO SPREAD ACROSS CENTRAL LOWER AS WELL. 12Z RUC/ETA HAVE PICKED UP ON THIS NORTHWARD SPREAD A LITTLE BETTER THAN PREVIOUS RUNS...BUT STILL LOOK TO BE A BIT ON THE SOUTH SIDE COMPARED TO LATEST RADAR OBSERVATIONS. BEST MOISTURE/LIFT IS FOCUSED ACROSS THE SOUTHERN CWA...WHERE CURRENT FORECAST HAS CATEGORICAL SNOW 2-4 INCHES OF ACCUMULATION /TOTAL ACCUMULATION...THIS AFTERNOON AND EVENING/. PRECIP TAPERED TO CHANCE THIS EVENING ACROSS THE NORTHERN CWA. GIVEN THE LATEST RADAR/MODEL TRENDS WILL LEAN TOWARD MORE OF A WIDESPREAD WORDING...BUT JUST LIGHT SNOW WILL LITTLE ACCUMULATIONS ACROSS THE NORTHERN CWA. AS FOR PRECIP TYPE...FORECAST SOUNDINGS CONTINUE TO POINT TO ALL SNOW FOR SOUTHEAST MICHIGAN. 12Z RUC HAS A LAYER 900MB-800MB UP TO +2C ACROSS NORTHEAST ILLINOIS THIS MORNING...BUT STILL QUITE DRY WITH DEWPOINT DEPRESSIONS OF 5C-10C TO PROVIDE SOME EVAPORATIVE COOLING. KORD REPORTING -PL/-FZRAPL WITH VFR VISIBILITIES IN THIS AREA. RUC INDICATES THIS WARM LAYER STAYING SOUTH OF THE CWA...WITH PROFILES ACROSS FAR SOUTHEAST LENAWEE APPROACHING -1C BUT NOT WARMING POSITIVE. THEN ONCE PRECIP BEGINS...THE PROFILE COOLS ENOUGH TO REMOVE ANY CONCERN FOR MIXED PRECIP. WILL KEEP JUST THE MENTION OF SNOW ACROSS THE SOUTHERN CWA FOR THE AFTERNOON. THANKS FOR COORD WITH APX/GRR. .DTX...NONE. BRAVENDER EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC 1027 AM EST TUE JAN 28 2003 DISC: 15Z SURFACE ANALYSIS SHOWS HIGH PRESSURE CENTERED ACROSS THE CAROLINAS/GA. SATELLITE SHOWS LOTS OF LOW CLOUDS JUST TO OUR WEST ACROSS NWRN GA/AL. BOTH MORNING RUC/MESOETA SHOW MOISTURE ASSOCIATED WITH LOW CLOUDS TO GRADUALLY PUSH EASTWARD DURING THE AFTERNOON. SKIES WILL REMAIN SUNNY FOR A GOOD PORTION OF THE DAY WITH SOME CLOUDS MOVING FROM WEST TO EAST ACROSS THE AREA DURING THE LATER HALF OF THE AFTERNOON. LOOKING A FORECAST AFTERNOON MAXES...BELIEVE THAT NORTHERN AREAS WILL STRUGGLE TO REACH 50 DEGREES AND WILL LOWER TEMPERATURES THERE INTO THE UPPER 40S. WINDS SHOULD BECOME MORE SW THROUGH THE AFTERNOON AS HIGH PRESSURE MOVES OFFSHORE AND COLD FRONT SAGS CLOSER TO THE AREA. OTHERWISE FORECAST GOOD FOR THE AFTERNOON. FCSTID = 77 CAE 52 39 59 46 / 0 10 40 60 AGS 53 36 61 45 / 0 10 40 60 SSC 52 38 59 47 / 0 10 40 60 OGB 53 38 61 47 / 0 10 40 60 .CAE... GA...NONE. SC...NONE. LCV sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 210 PM EST TUE JAN 28 2003 CURRENTLY...WK RIDGING ALOFT OVER MOST OF FL WITH 2 SHORTWAVES EVIDENT ON H2O VAPOR/RUC 400MB STREAMLINES. ONE IS OVER W TX WHILE THE OTHER IS DIVING INTO THE 4 CORNERS AREA. AT THE SFC...HI PRES RIDGE OVER SE U.S. WITH HIGHEST PRES CENTER RIGHT OVER SE GA AT 16Z. APPEARS TO BE A WK TROF OVER THE FL COASTAL WATERS (WHICH IS INDICATED BY ETA SUITE OF MODELS)...AND THIS FEATURE HAS ENHANCED THE THICKNESS OF SC EVEN AS THE AREA BECOMES SMALLER AS A WHOLE. WELL TO THE NW OF THE AREA...CONSIDERABLE AREA OF CLOUDINESS FROM N GA TO S AL ASSOCIATED WITH RETURN FLOW AROUND RIDGE AND ISENTROPIC LIFT. PUBLIC...CURRENT TRAJECTORY OF SC DECK OVER THE ATLC MAY TAKE IT INTO FLAGLER COUNTY OVERNIGHT...BUT AT MOST WILL BE PARTLY CLOUDY WITH BULK OF CLOUDS FURTHER S. MODELS AGREE THAT BULK OF CLOUDINESS WON'T MAKE IT INTO GA ZONES UNTIL WED...BUT WILL INDICATE INCREASING TREND IN EXTREME NW. SERIES OF SHORT WAVES WILL DIG E COAST TROF A BIT...BUT LITTLE DYNAMICS WITH THIS FEATURE. ATTENDANT SFC COLD FRONT WILL STALL NR THE FL/GA LINE...BEFORE EVENTUALLY BECOMING DIFFUSE. ONLY MINOR DAY TO DAY FLUCTUATIONS IN TEMPS WITH GRADUAL TRENDING UPWARD. LITTLE ADDITIONAL CHANGES TO PREVIOUS PACKAGE...AS MODELS REMAIN IN GOOD AGREEMENT WITH GENERAL FEATURES. EXTENDED...GFS SUITE STILL FAIRLY CONSISTENT WITH PROGRESSION OF FEATURES...SO LITTLE CHANGES WERE MADE EXCEPT FOR SOME TWEAKING OF TEMPS. NEXT CHANCE OF RAIN WILL BE LATE MON INTO EARLY TUE...BUT ONLY SLIGHT CHANCES ATTM. TEMPS PROGGED TO REMAIN NR OR SLIGHTLY ABOVE NORMAL THRU THE PERIOD. MARINE...WK ATLC TROF WILL DELAY FULL SCALE SHIFT OF WINDS TO S DIRECTION. HAVE STARTED WITH MESO-ETA WINDS IN 1ST COUPLE OF PERIODS...BEFORE SHIFTING TO THE GFS WIND SOLUTION IN LATER PERIODS. ALL-IN-ALL...WINDS WILL BE FAIRLY LIGHT THRU MOST OF THE PERIOD...WITH BRIEF INCREASES N OF THE AREA. PRELIM... FCSTID = 31 AMG 37 66 50 64 / 0 30 40 40 SSI 37 67 48 64 / 0 0 40 40 JAX 39 71 48 68 / 0 0 0 20 SGJ 43 70 49 67 / 0 0 0 20 GNV 38 72 47 70 / 0 0 0 20 OCF 40 72 47 72 / 0 0 0 10 .JAX... FL...NONE. GA...NONE. CARROLL fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1048 AM CST TUE JAN 28 2003 WILL BE CANCELING WINTER WEATHER ADVISORY FOR NORTHWEST ZONES THAT HAD BEEN IN EFFECT FOR THIS AFTERNOON AND EVENING. STRONG WAA CONTINUES ACROSS FORECAST AREA AS MOST SITES HAVE REACHED AROUND 30 DEGREES AND WARMER. LATEST ETA AND RUC CONTINUE TO INDICATE GOOD WARMING AND EXPECT TEMPS TO CLIMB ABOVE FREEZING EVERYWHERE THIS AFTERNOON. PRECIP OVER IOWA ASSOCIATED WITH SHORTWAVE AND RIGHT ENTRANCE REGION OF 120 KT JET IS PROGGED TO SLOWLY MOVE SOUTHEAST BUT IS EXPECTED TO ENCOUNTER DRY LAYER AND TAKE SOME TIME TO SATURATE. SOME LIGHT PRECIP MAY BE POSSIBLE THIS AFTERNOON. HOWEVER...THIS DELAY IN LAYER SATURATION SHOULD DECREASE CHANCES OF ADVISORY CRITERIA WEATHER FOR THIS AFTERNOON. DESPITE PRECIP SLIDING SOUTHEAST THROUGH FORECAST AREA TONIGHT WITH FRONTAL PASSAGE AND MAIN SHORT WAVE...MODELS SUGGEST ANY FREEZING PRECIP SHOULD BE SHORT LIVED PRIOR TO TURNING TO SNOW. SHOULD BE ABLE TO STAY BELOW ADVISORY CRITERIA WITH ONLY LOCALIZED TRAVEL PROBLEMS EXPECTED. .ILX...NONE. $$ BARKER il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO IL 1043 AM CST TUE JAN 28 2003 PUBLIC DISCUSSION FOR MORNING UPDATE FORECAST SOUNDINGS SHOW COLUMN COOLING LATE THIS MORNING AND THIS SUPPORTED BY ACARS. AS PRECIP AREA ACROSS IOWA MOVES EAST...LOWER LAYERS MOISTEN UP AND EVAPORATIVE COOLING SHOULD CHANGE ALL PRECIP TO SNOW. ETA/MESOETA QPF SHOWING 2 TO 3 TENTHS LIQUID BY EVENING. AS COLDER AIR MOVES IN EXPECT SNOW RATIOS TO INCREASE. THUS HAVE BUMPED TOTAL AMOUNTS UP TO 2 TO 4 INCHES BY EVENING ACROSS NORTHERN PART OF FA GENERALLY ALONG AND NORTH OF I80 WITH LESSER AMOUNTS SOUTH. TEMPS HAVE RISEN INTO THE LOWER 30S ALL BUT RFD AREA AND THIS SHOULD BE ABOUT IT AS CLOUDS THICKEN AND EXPECT TEMPS TO FALL AFTER SNOW BEGINS. .CHI...NONE. CMS AVIATION DISCUSSION FOR THE 12 UTC TAFS... THE ACARS SOUNDING AT ROCKFORD STILL SHOWS RELATIVELY DRY AIR AND AN INVERSION ABOUT 850 MB. THERE IS WARM AIR ADVECTION AT 850 MB AND THE AVN AND ETA MODELS KEEP THE ADVECTION THROUGH 18 UTC. WILL FORECAST FREEZING RAIN THROUGH 17 UTC. THE MESO ETA AND RUC MODELS FORECAST MAXIMUM VERTICAL VELOCITY ABOUT 17 TO 21 UTC. WILL FORECAST THE LOWEST CEILINGS AND SNOW AT THAT TIME. CEILINGS ABOUT 600 FEET TO 1500 FEET AND VISIBILITY DOWN TO 1/2 MILE. THE COLDER AIR COMES IN ABOUT 19 TO 20 UTC AND CHANGE THE PRECIPITATION WILL BE SNOW. THIS SYSTEM IS A WEAK WARM FRONT WITH MOST OF THE FORCING FROM DIVERGENCE FROM A JET STREAM AND ISENTROPIC OVERRUNNING. THE COLDEST AIR WILL NOT ARRIVE UNTIL WEDNESDAY. RADAR IS SHOWING INCREASING PRECIPITATION ALOFT. THE PRECIPITATION WILL EVENTUALLY REACH THE GROUND AS THE MOISTURE CONTENT OF THE AIR RISES. DEWPOINTS HAVE BEEN INCREASING IN THE TAFS AREA DURING THE LAST 6 HOURS. WILL FORECAST A SLOW END THE SNOW LATE TONIGHT AS SUBSIDENCE WILL MOVE INTO THE AREA. WHW il AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE WICHITA KS 1247 PM CST TUE JAN 28 2003 UPDATED ZONES AND ISC GRIDS TO LOWER TEMPERATURES IN THE NORTH, AND BRING THEM UP SEVERAL NOTCHES IN THE FAR SOUTHEAST. HIGHS ALREADY PUSHING 60 DEGREES IN FAR SOUTHEAST KANSAS. ALSO, INCREASED SURFACE WINDS SIGNIFICANTLY BEHIND THE FRONT. IN FACT THE FAR WESTERN CORRIDOR MAY COME CLOSE TO WIND ADVISORY CRITERIA, BUT WILL HOLD OFF ON THAT FOR NOW. FRANK --------------------------------------------------------------------- STRATUS AND FOG BEGINNING TO BURN OFF ACROSS MOST OF SOUTH CEN KS ATTM...EXCEPT SERN KS WHERE CLOUDS ARE A LITTLE THICKER AND SLOWER TO CLEAR. 15Z RUC ALSO SHOWS BEST LOW LEVEL MOISTURE ADVECTION IN THIS AREA OR JUST TO THE EAST OF THE THIS AREA IN SW MO. SO EXPECT SERN KS TO CLR LAST. EVEN WITH MORNING CLOUDS/FOG TEMPS OFF TO A GOOD START ACROSS THE AREA. AS COLD FRONT MOVES DOWN ACROSS KS TODAY...GOOD COMPRESSIONAL HEATING JUST AHEAD OF THE FRONT WILL ALLOW TEMPS TO RISE ABOVE GUID NUMBERS AND REACH PROJECTED HIGHS. SO WILL LEAVE TEMPS ALONE FOR NOW...BUT UPDATE CLOUD TRENDS. NOT MUCH COLD AIR BEHIND THE FRONT...SO RSL/SLN WILL STILL MAKE 50 TO 55 TODAY EVEN WITH EXTENSIVE CLOUDS AND WIND SHIFT. UPDATE OUT AFTER 17Z OBS ARE OUT. KETCHAM --------------------------------------------------------------- 325 AM CST TUE JAN 28 2003 MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE DENSE FOG AND LOW CLOUD POTENTIAL THIS MORNING AND THEIR AFFECT ON TEMPERATURES TODAY. THE REMAINDER OF THE FORECAST LOOKS PRETTY TAME, BUT WE WILL HAVE TO WATCH THE SYSTEM COMING DOWN THE NORTHERN PLAINS THURSDAY NIGHT GIVING US OUR PRECIP CHANCES. TODAY: LATEST FOG IMAGERY SHOWING LOW CLOUDS CONTINUING TO ADVECT IN FROM EASTERN OKLAHOMA. ON THE OUTER EDGES OF THESE CLOUDS FOG WAS BEGINNING TO DEVELOP. RIGHT NOW VSBY ARE GENERALLY RANGING FROM 4-5SM MAINLY IN CENTRAL AND SOUTH CENTRAL KANSAS, BUT I WOULD ANTICIPATE THIS TO LOWER AS THE MORNING WEARS ON. THE REASONS BEING IS THE BOUNDARY LAYER MOISTURE IS BECOMING VERY SATURATED AS SOUTHERLY FLOW CONTINUES TO PUSH MOISTURE IN FROM OKLAHOMA, AND VERY LIMITED MIXING IS TAKING PLACE IN THE LOWEST 100M ACCORDING TO THE LATEST SODAR PROFILES. THIS WOULD HELP YIELD TO ADVECTION FOG IF THIS TREND CONTINUES. WE ARE NOT CONFIDENT ENOUGH YET TO ISSUE A DENSE FOG ADVISORY, BUT IF TRENDS CONTINUE AS SUCH, WE MAY END UP ISSUING A DENSE FOG ADVISORY FOR SOUTH CENTRAL AND CENTRAL KANSAS BY DAYBREAK. WE WILL HIT IT HARD IN THE ZONES AND HWO FOR NOW. THEN THE NEXT QUESTION FOR TODAY WILL BE WHEN THE CLOUDS WILL BREAK. IT APPEARS AS IF SOUTHEAST KS WILL HOLD ONTO THE CLOUDS THE LONGEST DUE TO A THICKER LAYER IN PLACE. SOUTH CENTRAL AND CENTRAL KANSAS WOULD MOST LIKELY SEE SUNSHINE BY MIDDAY. MEANWHILE, THE FRONT IS PROGGED TO PUSH THROUGH SOUTH CENTRAL KANSAS DURING THE AFTERNOON. THIS COULD BRING FORTH SOME COMPRESSIONAL HEATING WHICH WILL HELP THEM GO ABOVE GUIDANCE AND CLIMB TO NEAR 60. FURTHER NORTH AND EAST, WE PLAYED THE CONSERVATIVE ROUTE AND PLAYED CLOSE TO GUIDANCE NUMBERS. TONIGHT: THE MODELS SHOW THE LOW CLOUDS LAGGING WELL BEHIND THE FRONT. THINGS SHOULD BEGIN TO SATURATE UP DURING THE EVENING AS 280-285K THETA SURFACES BEGIN RISING WHICH WILL HELP INDUCE THE CLOUDS. WE KEPT TEMPERATURES FAIRLY CLOSE TO PREVIOUS NUMBERS TO REFLECT THIS WHICH IS IN LINE WITH GUIDANCE. TOMORROW: THE MAIN QUESTION WILL BE HOW LONG TO HOLD ONTO THE CLOUDS AS HIGH PRESSURE GRADUALLY PUSHES EAST INTO THE UPPER MIDWEST. THIS WILL ALLOW OUR FLOW TO TURN MORE NORTHEASTERLY WHICH MAY PROLONG THE CLOUDS A LITTLE LONGER. 285K THETA SURFACES ALSO DO SHOW SOME RISES WHICH MAY AID IN THE SITUATION. WE HAVE LOWERED TEMPERATURES CLOSER TO THE GUIDANCE NUMBERS TO REFLECT THIS. TOMORROW NIGHT: RETURN FLOW IS SETTING UP AGAIN AS THE HIGH GRADUALLY SHIFTS EAST TO THE OHIO VALLEY. SOME WARM AIR ADVECTION WILL BE TAKING PLACE IN THE MID LEVELS WHICH WILL HELP YIELD TO SOME MID LEVEL CLOUDS. WE WILL KEEP TEMPERATURES CLOSER TO FWC NUMBERS TO REFLECT THIS. THURSDAY-THURSDAY NIGHT: A STRONG UPPER LEVEL WAVE WILL DIVE IN FROM THE NORTHERN PLAINS. IT APPEARS THE MODELS HAVE AMPLIFIED THIS WAVE A LITTLE MORE FROM THE PREVIOUS RUNS. AS A RESULT, WE COULD SEE A BETTER CHANCE OF MAINLY RAIN THURSDAY NIGHT, BUT THERE IS SOME QUESTION ON HOW MUCH COOLING WILL TAKE PLACE IN THE LOW LEVELS DUE TO EVAPORATIVE COOLING AND SOME INSTABILITY ALOFT. FRIDAY-MONDAY: THE NEXT SYSTEM APPEARS TO FLY OUT OF THE ROCKIES INTO THE PLAINS ON SUNDAY. UNTIL THEN, A BIG WARM UP IS EXPECTED FOR SATURDAY WITH TEMPERATURES POSSIBLY REACHING THE 60S. IT APPEARS THE ECMWF/UKMET IS COMING IN LINE WITH THE GFS SOLUTION ON THE PLACEMENT OF THE LOW PRESSURE SYSTEM. NOW THE MAIN QUESTION WILL BE HOW MUCH MOISTURE RETURN WE WILL SEE. WE HAVE KEPT A CHANCE OF RW- GOING FOR NOW. FCSTID = 18/COX ICT 60 29 43 27 / 5 0 0 10 HUT 58 29 43 27 / 5 0 0 10 EWK 59 29 43 27 / 5 0 0 10 EQA 60 29 43 27 / 5 0 0 10 WLD 60 29 43 27 / 5 0 0 10 RSL 50 26 42 25 / 5 0 0 10 GBD 52 26 42 25 / 5 0 0 10 SLN 56 28 41 25 / 5 0 0 10 MPR 57 28 41 25 / 5 0 0 10 CFV 55 29 42 27 / 5 0 0 10 CNU 55 29 42 27 / 5 0 0 10 K88 55 29 42 27 / 5 0 0 10 .ICT...NONE. ks AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE WICHITA KS 1055 AM CST TUE JAN 28 2003 STRATUS AND FOG BEGINNING TO BURN OFF ACROSS MOST OF SOUTH CEN KS ATTM...EXCEPT SERN KS WHERE CLOUDS ARE A LITTLE THICKER AND SLOWER TO CLEAR. 15Z RUC ALSO SHOWS BEST LOW LEVEL MOISTURE ADVECTION IN THIS AREA OR JUST TO THE EAST OF THE THIS AREA IN SW MO. SO EXPECT SERN KS TO CLR LAST. EVEN WITH MORNING CLOUDS/FOG TEMPS OFF TO A GOOD START ACROSS THE AREA. AS COLD FRONT MOVES DOWN ACROSS KS TODAY...GOOD COMPRESSIONAL HEATING JUST AHEAD OF THE FRONT WILL ALLOW TEMPS TO RISE ABOVE GUID NUMBERS AND REACH PROJECTED HIGHS. SO WILL LEAVE TEMPS ALONE FOR NOW...BUT UPDATE CLOUD TRENDS. NOT MUCH COLD AIR BEHIND THE FRONT...SO RSL/SLN WILL STILL MAKE 50 TO 55 TODAY EVEN WITH EXTENSIVE CLOUDS AND WIND SHIFT. UPDATE OUT AFTER 17Z OBS ARE OUT. KETCHAM --------------------------------------------------------------- 325 AM CST TUE JAN 28 2003 MAIN CONCERN WITH THIS FORECAST PACKAGE WILL BE THE DENSE FOG AND LOW CLOUD POTENTIAL THIS MORNING AND THEIR AFFECT ON TEMPERATURES TODAY. THE REMAINDER OF THE FORECAST LOOKS PRETTY TAME, BUT WE WILL HAVE TO WATCH THE SYSTEM COMING DOWN THE NORTHERN PLAINS THURSDAY NIGHT GIVING US OUR PRECIP CHANCES. TODAY: LATEST FOG IMAGERY SHOWING LOW CLOUDS CONTINUING TO ADVECT IN FROM EASTERN OKLAHOMA. ON THE OUTER EDGES OF THESE CLOUDS FOG WAS BEGINNING TO DEVELOP. RIGHT NOW VSBY ARE GENERALLY RANGING FROM 4-5SM MAINLY IN CENTRAL AND SOUTH CENTRAL KANSAS, BUT I WOULD ANTICIPATE THIS TO LOWER AS THE MORNING WEARS ON. THE REASONS BEING IS THE BOUNDARY LAYER MOISTURE IS BECOMING VERY SATURATED AS SOUTHERLY FLOW CONTINUES TO PUSH MOISTURE IN FROM OKLAHOMA, AND VERY LIMITED MIXING IS TAKING PLACE IN THE LOWEST 100M ACCORDING TO THE LATEST SODAR PROFILES. THIS WOULD HELP YIELD TO ADVECTION FOG IF THIS TREND CONTINUES. WE ARE NOT CONFIDENT ENOUGH YET TO ISSUE A DENSE FOG ADVISORY, BUT IF TRENDS CONTINUE AS SUCH, WE MAY END UP ISSUING A DENSE FOG ADVISORY FOR SOUTH CENTRAL AND CENTRAL KANSAS BY DAYBREAK. WE WILL HIT IT HARD IN THE ZONES AND HWO FOR NOW. THEN THE NEXT QUESTION FOR TODAY WILL BE WHEN THE CLOUDS WILL BREAK. IT APPEARS AS IF SOUTHEAST KS WILL HOLD ONTO THE CLOUDS THE LONGEST DUE TO A THICKER LAYER IN PLACE. SOUTH CENTRAL AND CENTRAL KANSAS WOULD MOST LIKELY SEE SUNSHINE BY MIDDAY. MEANWHILE, THE FRONT IS PROGGED TO PUSH THROUGH SOUTH CENTRAL KANSAS DURING THE AFTERNOON. THIS COULD BRING FORTH SOME COMPRESSIONAL HEATING WHICH WILL HELP THEM GO ABOVE GUIDANCE AND CLIMB TO NEAR 60. FURTHER NORTH AND EAST, WE PLAYED THE CONSERVATIVE ROUTE AND PLAYED CLOSE TO GUIDANCE NUMBERS. TONIGHT: THE MODELS SHOW THE LOW CLOUDS LAGGING WELL BEHIND THE FRONT. THINGS SHOULD BEGIN TO SATURATE UP DURING THE EVENING AS 280-285K THETA SURFACES BEGIN RISING WHICH WILL HELP INDUCE THE CLOUDS. WE KEPT TEMPERATURES FAIRLY CLOSE TO PREVIOUS NUMBERS TO REFLECT THIS WHICH IS IN LINE WITH GUIDANCE. TOMORROW: THE MAIN QUESTION WILL BE HOW LONG TO HOLD ONTO THE CLOUDS AS HIGH PRESSURE GRADUALLY PUSHES EAST INTO THE UPPER MIDWEST. THIS WILL ALLOW OUR FLOW TO TURN MORE NORTHEASTERLY WHICH MAY PROLONG THE CLOUDS A LITTLE LONGER. 285K THETA SURFACES ALSO DO SHOW SOME RISES WHICH MAY AID IN THE SITUATION. WE HAVE LOWERED TEMPERATURES CLOSER TO THE GUIDANCE NUMBERS TO REFLECT THIS. TOMORROW NIGHT: RETURN FLOW IS SETTING UP AGAIN AS THE HIGH GRADUALLY SHIFTS EAST TO THE OHIO VALLEY. SOME WARM AIR ADVECTION WILL BE TAKING PLACE IN THE MID LEVELS WHICH WILL HELP YIELD TO SOME MID LEVEL CLOUDS. WE WILL KEEP TEMPERATURES CLOSER TO FWC NUMBERS TO REFLECT THIS. THURSDAY-THURSDAY NIGHT: A STRONG UPPER LEVEL WAVE WILL DIVE IN FROM THE NORTHERN PLAINS. IT APPEARS THE MODELS HAVE AMPLIFIED THIS WAVE A LITTLE MORE FROM THE PREVIOUS RUNS. AS A RESULT, WE COULD SEE A BETTER CHANCE OF MAINLY RAIN THURSDAY NIGHT, BUT THERE IS SOME QUESTION ON HOW MUCH COOLING WILL TAKE PLACE IN THE LOW LEVELS DUE TO EVAPORATIVE COOLING AND SOME INSTABILITY ALOFT. FRIDAY-MONDAY: THE NEXT SYSTEM APPEARS TO FLY OUT OF THE ROCKIES INTO THE PLAINS ON SUNDAY. UNTIL THEN, A BIG WARM UP IS EXPECTED FOR SATURDAY WITH TEMPERATURES POSSIBLY REACHING THE 60S. IT APPEARS THE ECMWF/UKMET IS COMING IN LINE WITH THE GFS SOLUTION ON THE PLACEMENT OF THE LOW PRESSURE SYSTEM. NOW THE MAIN QUESTION WILL BE HOW MUCH MOISTURE RETURN WE WILL SEE. WE HAVE KEPT A CHANCE OF RW- GOING FOR NOW. FCSTID = 18/COX ICT 60 29 43 27 / 5 0 0 10 HUT 58 29 43 27 / 5 0 0 10 EWK 59 29 43 27 / 5 0 0 10 EQA 60 29 43 27 / 5 0 0 10 WLD 60 29 43 27 / 5 0 0 10 RSL 50 26 42 25 / 5 0 0 10 GBD 52 26 42 25 / 5 0 0 10 SLN 56 28 41 25 / 5 0 0 10 MPR 57 28 41 25 / 5 0 0 10 CFV 55 29 42 27 / 5 0 0 10 CNU 55 29 42 27 / 5 0 0 10 K88 55 29 42 27 / 5 0 0 10 .ICT...NONE. ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 350 PM CST TUE JAN 28 2003 FORECAST CONCERN WILL BE LIGHT SNOW CHANCES TONIGHT AND THEN TIMING AND STRENGTH OF NEXT SHORT WAVE TO AFFECT CWA ON THURSDAY. 20Z SURFACE ANALYSIS SHOWING RIDGE AXIS EXTENDING FROM NORTHEAST NORTH DAKOTA AND THEN INTO EASTERN SOUTH DAKOTA. WEAK SLP MINIMUM LOCATED ACROSS FAR NORTHEAST SOUTH DAKOTA WITH WEAK INVERTED PRESSURE TROUGH INTO WESTERN NORTH DAKOTA. BRUNT OF COLD AIR ADVECTION HAS OCCURRED ACROSS NORTHEAST SOUTH DAKOTA THIS AFTERNOON. RATHER COMPLICATED UPPER FLOW PATTERN SETTING UP FOR TONIGHT AS VORT LOBE WILL DROP INTO REGION FROM ALBERTA TOWARDS MORNING WITH ANOTHER WEAKER SHORT WAVE PASSING EAST OF THE UPPER RIDGE AXIS AND GETTING SHEARED OUT. SOME SCATTERED FLURRIES CURRENTLY ACROSS NORTHEAST CWA ASSOCIATED WITH COLD ADVECTION. A BETTER CHANCE OF SNOW STILL LOOKS TO BE LATER THIS EVENING INTO THE OVERNIGHT. INCREASING FRONTOGENESIS IN THE 850-800 HPA LAYER NOTED IN RUC/MESO-ETA DATA WITH APPROACH OF THIS SHORT WAVE WITH AXIS OF THIS FORCING LIKELY TO SET UP FROM NORTH CENTRAL SOUTH DAKOTA DOWN INTO SOUTHEAST SOUTH DAKOTA. LOW LEVEL LIFT WILL BE FOCUSED MAINLY OVER NORTH CENTRAL AND CENTRAL SOUTH DAKOTA WITH MORE OF MID LEVEL FOCUS TO LIFT ACROSS THE NORTHEAST. MIXING RATIOS STILL AROUND 3 G/KG ACROSS SOUTHWEST CWA AND MOISTURE COMBINED WITH FRONTO FORCING WILL CALL FOR AT LEAST HIGH CHANCE POPS ACROSS MOST OF CWA. WILL GO WITH LOWER CHANCE POPS ACROSS FAR NORTHEAST SOUTH DAKOTA ON COLD SIDE OF LOW LEVEL BOUNDARY WITH DRIER LOW LEVEL AIR. MODELS GENERATING AROUND 0.15 INCHES OF LIQUID IN NARROW BAND OF FRONTOGENESIS FORCING...BUT UPSTREAM RADAR TRENDS WOULD SEEM TO INDICATE MODELS OVERDOING QPF AND STILL SOME UNCERTAINTY OF EXACTLY HOW SHORT WAVES WILL PHASE TONIGHT. COLD AIR FINALLY SEEPS ACROSS REST OF AREA TOMORROW WITH PASSAGE OF THIS SHORT WAVE AS SURFACE HIGH SETTLES OVER EASTERN SOUTH DAKOTA. MODELS DEPICTING SOME STRONG SUBSIDENCE AND MID LEVEL DRYING DURING AFTERNOON AND WILL GO WITH DECREASING CLOUD TREND FROM NORTH TO SOUTH. TEMPERATURES SHOULD GENERALLY RANGE FROM NEAR 10 ACROSS FAR NORTHEAST TO MID 20S ACROSS FAR SOUTHWEST. SURFACE ANTICYCLONE MOVES EASTWARD WEDNESDAY NIGHT INTO THURSDAY WITH SOUTHERLY SURFACE FLOW DEVELOPING ONCE AGAIN. WITH WARM ADVECTION WEDNESDAY NIGHT INTO THURSDAY MORNING...WILL GO WITH NEARLY STEADY OR SLOWLY RISING WORDING. ETA/GFS DISAGREE WITH DETAILS OF ANOTHER APPROACHING WAVE FOR THURSDAY BUT OVERALL TIMING IS NOT TOO DISSIMILAR. BUFFER DATA INDICATING SOME POTENTIAL FOR EVEN SOME FREEZING PRECIP MAINLY ACROSS NORTHERN CWA. WILL KEEP RAIN OR SNOW WORDING FOR NOW AND CONTINUE TO FINE TUNE IN LATER FORECASTS. BY LATE THURSDAY NIGHT...THIS SHORT WAVE EXITS AREA WITH SOME WEAK COLD ADVECTION BEHIND THIS WAVE...BUT UPSTREAM LOW LEVEL TEMPS IN SOUTHWEST CANADA REMAIN RELATIVELY WARM AND CAA WILL BE RELATIVELY WEAK. ...LONG TERM... MODELS ARE IN FAIR AGREEMENT THROUGH EARLY PART OF EXTENDED. FRIDAY MORNING THE SFC TROF/COLD FRONT EXITS EAST OF CWA WITH BUILDING SFC HIGH AND BUILDING 5H AND 7H RIDGE TO WEST. DRYING TAKES PLACE THROUGH THE LAYERS...HOPEFULLY LETTING THE CWA SEE SOME SUNSHINE BY THE AFTERNOON. THE GFS HAS OVERDONE THE LIGHT SNOW FCST HERE...AND CHOSE TO REMAIN DRY...SIMILAR TO CANADIAN AND NOGAPS SOLNS. WITH NICE TEMP RECOVERY ALOFT AND BUILDING HEIGHTS...HAVE TRENDED TOWARD THE WARMER FMR GUIDANCE ALL AREAS. FOR SATURDAY...THE UPPER RIDGE BEGINS TO FLATTEN WITH 5H AND 7H TROFS APPROACHING FROM THE WEST. THE 85H THERMAL RIDGE PASSES THROUGH THE REGION DURING THE AFTERNOON...AND A SFC WARM FRONT MOVES EAST ACROSS THE CWA AT THE SAME TIME. SFC LOW PRESSURE MOVES WRN NEB/ERN WY BY END OF DAY SATURDAY...WITH VERY STRONG WAA TAKING PLACE BY SATURDAY AFTERNOON. PCPN TYPE IS A CONCERN HERE. COULD BE SIMILAR TO THE WARM FRONTAL PASSAGE THAT OCCURRED MONDAY...WHERE SNOW BREAKS OUT PRE-FRONTAL...THEN MIXED PSBL CLOSER TO FRONT. FOR NOW...WILL MENTION CHANCE OF SNOW NRN CWA FRIDAY NIGHT...TURNING OVER TO RAIN SATURDAY AFTERNOON AS WAA PUSHES MERCURY ABOVE FREEZING TEMPS. MODELS HAVE SOME TROUBLE SUNDAY. OPERATIONAL GFS EXTENDED SWINGS 5H TROF THROUGH MIDWEST...WITH BEST ENERGY SOUTH TOWARD OK/KS/TX REGION. GFS ENSEMBLES PAINT A DIFFERENT PICTURE AND SEEM MORE IN LINE WITH CANADIAN/ECMWF/NEAR TERM GFS. UPPER TROF DROPS INTO WRN NEBRASKA WITH SFC LOW MOVING EAST THROUGH NEBRASKA DURING DAY ON SUNDAY. THE ENSEMBLE MEMBERS AGREE WITH THIS FORECAST...ALL WHICH POINT TOWARD PSBL SNOWSTORM FOR CWA ON SUNDAY. HOWEVER...AMOUNT OF WAA TAKING PLACE AHEAD OF LOW MAY KEEP MAJORITY OF PCPN AS RAIN BEFORE CHANGING OVER LATER SUNDAY. 5H THICKNESS VALUES DON'T FALL BELOW 540 UNTIL 00Z MONDAY. FOR NOW...WILL JUST KEEP CHC SNOW MENTION AND SEE HOW THINGS SHAKE OUT. FOR MONDAY...SFC HIGH PRESSURE BUILDS DOWN RED RIVER VALLEY HELPING TO DRY THINGS OUT A BIT. LEE TROFING OUT WEST WILL BRING BACK CHC OF LIGHT SNOW TO WRN CWA MONDAY. NO REAL ENERGY ALOFT ASSOCIATED WITH FEATURE...AND NOT THAT HIGH OF CONFIDENCE IN FCST. BY TUESDAY...NEXT IN SERIES OF 5H WAVES DROP INTO CWA...WITH ASSOC SFC LOW DROPPING SOUTH INTO AREA AS WELL. TEMPS HERE COULD BE TRICKY DUE TO WAA AHEAD OF LOW. AS 7H TROF DROPS INTO CWA...SHOULD BE ABLE TO WRING OUT A FEW FLAKES OF SNOW...SO HAVE INCLUDED THE CHC. TEMP WISE...THROUGH SUNDAY LEANED TOWARD THE WARMER FMR GUIDANCE. HOWEVER...MONDAY AND TUESDAY GUIDANCE WAS CLOSE AND GENERALLY STUCK CLOSE TO. .ABR...NONE MARSILI/HINTZ sd