AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SACRAMENTO CA 900 PM PDT SUN OCT 13 2002 REX BLOCK CONTINUING OVER EASTERN PACIFIC WITH ONLY WEAK DISTURBANCES MOVING UNDER UPPER LOW. SATELLITE DATA SHOWS IMPRESSIVE DEEP MOISTURE SOUTH OF 20N. UPPER LAYERS OF THIS MOISTURE ARE STREAMING NORTHEAST IN SUBTROPICAL JET STREAM AND ARE SEEN BEING LIFTED BY THE MOST RECENT OF THESE DISTURBANCES AND SPREADING INTO BAY AREA. RUC 300MB DIVERGENCE FIELD DEPICTS THIS AREA EXTREMELY WELL. BOTH FAIRFIELD AND OAKLAND ARE REPORTING HIGH CEILINGS...BUT IR DATA SHOWS CONSIDERABLY THINNER CLOUDS UPSTREAM IN ARE OF DECREASING UPPER DIVERGENCE. MODELS CONTINUE TO PORTRAY KEEPING THE DEEPEST MOISTURE AND WEATHER SOUTH AND EAST OF THE SACRAMENTO CWA AS LOW FINALLY DRIFTS INLAND ON TUESDAY. MARGINAL INSTABILITY WILL GET A LITTLE HELP FROM UPSLOPE FLOW IN THE NORTHERN SIERRA LATE IN THE DAY FOR A FEW SHOWERS AND MAYBE AN ISOLATED THUNDERSTORM. ENOUGH INSTABILITY REMAINS OVER THE SIERRA THROUGH THURSDAY FOR CLOUDS AND SHOWERS...THEN AVN SHOWS SOUTHERN BRANCH OF EASTERN PACIFIC STRENGTHENING WITH A SHORTWAVE MOVING INTO SOUTHERN CALIFORNIA AND SENDING THE CLOSED LOW ON ITS WAY THURSDAY NIGHT. THIS SORT OF THING COULD EASILY OCCUR EARLIER OR LATER. COOLING IN THE HIGH TERRAIN TUESDAY...AND FOR THE VALLEY WEDNESDAY. LITTLE CHANGE THURSDAY WITH SOME WARMING EXPECTED UNDER INCREASING PRESSURE FRIDAY. NO UPDATES. SJC STO...NONE. ca EAST CENTRAL FLORIDA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 355 PM EDT SUN OCT 13 2002 CURRENT WX... ACTIVE ECSB STRADDLING THE COASTAL/INTERIOR COUNTIES THIS AFTN WITH A BROKEN LINE OF RW/TRW RUNNING THE LENGTH OF THE E FL COAST. FURTHER NW...AN ACTIVE OUTFLOW BOUNDARY RIDING AHEAD IS PRODUCING STRONG TRW OVER THE BIG BEND AREA. STRONG COLD FRONT EXTENDING FROM S TX NEWD THROUGH THE TN VALLEY PUSHING SLOWLY INTO THE SERN STATES...LEADING EDGE OF THE H85-H70 THETA-E GRADIENT IS ALREADY IMPINGING ON THE WRN PANHANDLE...SFC DEWPOINTS DROPS ACROSS THE FRONT AVERAGING 25-30F DEG ALONG ITS LENGTH. OVER THE WRN CARIBBEAN...THE BROAD AREA OF LOW PRESSURE CONTINUES TO SHOW SIGNS OF DEVELOPMENT. FCST DISC... WILL NEED TO STEP POP UP A BIT TONIGHT AS THE OUTFLOW BOUNDARY OVER THE BIG BEND AREA PUSHS E AND COLLIDES WITH THE ECSB. COLLSION SHOULD OCCUR W OF THE KMCO/KSFB AREA...WILL GO WITH LIKELY POPS OVER LAKE COUNTY. WILL GO SCT/ISOLD ELSEWHERE AS THE H85-H50 STEERING FLOW REMAINS RATHER ANEMIC...DO NOT EXPECT ANY OF TONIGHTS CONVECTION TO WORK ITS WAY BACK TO THE COAST. WET WX PATTERN IN STORE FOR FL FOR THE NEXT 48HRS AS IT APPEARS THE BAROCLINIC FRONT AND THE BAROTROPIC SYSTEM WILL USE FL AS ITS BATTLEGROUND. THE TROPICAL WAVE IN THE WRN CARIB IS BECOMING MORE ORGANIZED AND MAY DEVELOP INTO A DEPRESSION WITHIN THE NEXT DAY OR SO...PLEASE REFER TO OFFICIAL NHC PRODUCTS FOR FULL INFORMATION. AN H85-H50 COL OVER THE NRN GOMEX IS SANDWICHED BETWEEN A WEAK ATLC RIDGE OVER THE FL PENINSULA/ERN GOMEX AND A WEAK RIDGE S OF THE RIO GRAND VALLEY. AS THE TROPICAL SYSTEM DEVELOPS...THERE IS A GOOD CHANCE IT WILL TRY TO "FEEL OUT" THE COL AND PUSH N ACROSS WRN CUBA...GFS MODEL BRINGS A BROAD LOW INTO THE FL STRAITS AFT 12Z TUE. MEANWHILE...THE COLD FRONT OVER THE SE U.S. WILL STALL OVER NEAR THE FL/GA BORDER AS IT RUNS INTO THE ATLC RIDGE. THE FRONT COULD PENETRATE AS FAR S AS THE BIG BEND AREA...BUT ANY FURTHER S IS UNLIKELY. LATEST RUC ANALYSIS SHOWS A 25-50KT W/NWRLY PUSH FROM THE H85-H50 WINDS OVER THE OH RIVER VALLEY AND THE UPR MIDWEST...WHICH WEAKENS TO A 10-15KT NWRLY PUSH OVER THE LWR MS VALLEY. THIS INDICATES THE NRN HALF OF THE FRONT IS BEGINNING TO OUTRACE AND ABANDON ITS SRN EXTENTION.. THE FRONT WILL WEAKEN THE RIDGING OVER THE AREA...ALLOWING THE DEVELOPING TROPICAL SYSTEM TO WORK ITS WAY N. INCREASING SERLY FLOW AHEAD OF THE SYSTEM WILL COMBINE WITH DEEP MOISTURE AND A BAROCLINIC BOUNDARY TO THE NORTH TO PRODUCE INCREASINGLY STRONG ISENTROPIC LIFT ACROSS THE PENINSULA MON NIGHT INTO TUE. AT THE SAME TIME...A +100KT H25 JET MAX OVER THE SW U.S. WILL PUSH EAST INTO THE GOMEX AND BEGIN TO INTERACT WITH THE WRN EXTENSION OF THE JET THAT IS DRIVING THE AFOREMENTIONED COLD FRONT. MODELS INDICATING A COUPLED JET PATTERN DEVELOPING OVER THE NRN GOMEX...LEADING TO CYCLOGENESIS ALONG THE STALLED FRONT. THE ENTIRE MESS IS EXPECTED TO DUKE IT OUT OVER FL...POPS WILL INCREASE TO LIKELY CAT BY TUE. CONDTIONS SHOULD IMPROVE RAPIDLY ON WED AS THE COMBINED LOW IS KICKED NE BY A REINFORCING S/WV TROF PUSHING OUT OF THE PAC NW. THE LOW WILL ADD THE FINAL SHOT NECESSARY TO USHER IN THE FIRST SHOT OF AUTUMN AIR TO THE FL PENINSULA WED NIGHT INTO THU. MARINE...NO SIGNIFICANT WINDS/SEAS EXPECTED OVERNIGHT...BUT CONDITIONS WILL BEGIN TO DETERIORATE LATE MON AS THE FRONT STALLS AND THE TROPICAL SYSTEM BEGINS TO PUSH N. EXPECT WINDS/SEA TO INCREASE TO CAUTIONARY LEVELS ON WED AS THE LOW PUSHES AWAY FROM FL AND THE TIGHTEN PGRAD PUSHES THE COLD FRONT THROUGH THE STATE. PRELIMINARY NUMBERS... DAB EE 072/083 073/084 067 366 MCO EE 072/086 071/085 068 456 MLB EE 074/084 074/084 069 346 81 .MLB...NONE. PUBLIC/MARINE...BRAGAW AVIATION/FIRE WX...GLITTO fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 215 PM EDT SUN OCT 13 2002 SURFACE ANALYSIS HAS WEAK PRE-FRONTAL TROUGH OVER N FL WITH OVERALL NW-N FLOW OVER CWA. COLD FRONT APPEARS TO STRETCH FROM CENTRAL AL TO NORTHERN GA. THETA-E PATTERN DEPICTS IT WELL. AREA 88DS DEPICT AFTERNOON CONVECTION DEVELOPING OVER MOST OF CWA...WITH MAIN FOCUS IN SW GA & N FL. 12Z TLH SOUNDING HAVING A PRECIP WATER VALUE OF 1.94 INCHES...LI OF -8.3...CAPE OF 3810 J/KG...& WITH S-SW FLOW 5-15 KNTS SURFACE TO 20K FT...& COOLING NOTED IN THE MID-LEVELS. SOME DIFFERENTIAL HEATING & OUTFLOW BOUNDARIES ADDING TO CONVECTION DEVELOPMENT. MESOETA & RUC SHOW SHORTWAVE ENERGY...& STILL BELIEVE A FEW STRONG STORMS OR SEVERE MAY BE POSSIBLE. LAPS DATA HIGHLIGHTING CAPE...LI & OMEGA MAXES OVER N FL. MODELS CONSISTENT THROUGH MONDAY...WITH BOUNDARY TO DRIFT THROUGH CWA...SWITCHING WINDS TO N-NE...WITH DRYING TREND FROM SE AL TO N FL. BUT THEN AS BOUNDARY STALLS OVER N FL...& UPPER SHORTWAVE ENERGY MOVES INTO THE AREA FROM THE WEST...A SURFACE LOW OR INVERTED TROUGH FORMS AS DEPICTED BY ALL MODELS...AVN STRONGEST & WETTEST. BY TUESDAY...ETA HAS LOW IN NORTHERN GULF...WHILE AVN HAS IT OVER SE AL WITH STRONGER INVERTED TROUGH OVER CWA. UPPER TROUGH DEEPENS OVER SOUTHERN PLAINS TO MISS VALLEY. MOISTURE INFLUX WITH LIFT WILL BE PRESENT TO KEEP AT LEAST GOOD POP IN FORECAST. LATER TUESDAY...ALL PULL THIS SYSTEM TO NE...& THEN ALLOW DRYING TO FILTER INTO CWA INTO WEDNESDAY. THEN THE TEMPS WILL RESPOND & BECOME MUCH COOLER THURSDAY THROUGH SATURDAY. A TRICKY FORECAST MONDAY THROUGH WEDNESDAY AS SYSTEM MOVES THROUGH CWA...THEN A TROPICAL SYSTEM BEGINS TO SHOW IN THE AVN OVER SE CARIBBEAN. AT THIS TIME...AVN PROGS THIS TO MAINLY AFFECT SOUTH FL. BUT WILL HAVE TO WATCH. OTHERWISE...WITH CLOUDS & CHANCES OF RAIN...TEMPS WILL BE CLOSER TO NORMALS WITH 50S TO LOWER 60S AS LOWS...WHILE HIGHS IN THE LOWER 80S TO MID 70S. MARINE: NO HEADLINES IN THE FIRST 24 HRS. AS SURFACE LOW FORMS...SCEC MAY BE NEEDED. BY WEDNESDAY...SCA MAY BE NEEDED. FIRE WEATHER: NO HEADLINES WITH HIGH HUMIDITIES & PRECIP. EXTENDED: AS FRONT PUSHES THROUGH ON WEDNESDAY...MUCH COOLER & DRIER AIRMASS TO TAKE OVER THROUGH THE REST OF THE WEEK. THIS WILL BE THE LOWEST TEMPS OF THE EARLY FALL SEASON. PRELIM NUMBERS: TLH 070 083 067 078 7567 PFN 072 080 069 077 5567 DHN 066 078 063 074 5556 ABY 066 078 063 074 7557 VLD 068 081 065 076 7557 .TLH... AL...NONE. GA...NONE. FL...NONE. MCT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 10 AM EDT SUN OCT 13 2002 SURFACE ANALYSIS HAS PRE-FRONTAL TROUGH & UPPER ENERGY HELP DEVELOP SCATTERED CONVECTION THIS MORNING...& AREA 88DS DEPICT THIS AS IT IS PUSHING E-NE. COLD FRONT OVER CENTRAL MS TO NORTHERN AL. TROUGH IS SWITCHING WINDS TO THE NW-N OVER CWA. 12Z TLH SOUNDING HAD A PRECIP WATER VALUE OF 1.94 INCHES...LI OF -8.3...CAPE OF 3810 J/KG...& WITH S-SW FLOW 5-15 KNTS SURFACE TO 20K FT. ALSO COOLING NOTED IN THE MID-LEVELS. SOME DIFFERENTIAL HEATING WILL ADD TO SOME CONVECTION. WITH OVERALL INSTABILITY & UPPER ENERGY SHOWN IN MESOETA & RUC...A FEW STRONG STORMS OR SEVERE MAY BE POSSIBLE. CURRENT FORECAST HAS GOOD HANDLE ON POP & COVERAGE. WILL TWEAK WITH LATE MORNING UPDATE. OTHERWISE...SHORT-TERM MARINE FORECAST GOOD...BUT SCEC TO SCA WILL BE LATER AS COLD FRONT DRIFTS THROUGH. NO SHORT-TERM FIRE WEATHER CONCERNS. .TLH... AL...NONE. GA...NONE. FL...NONE. MCT fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SHREVEPORT LA 1040 AM CDT SUN OCT 13 2002 COLD FRONT FINALLY REACHING SOUTHERN PORTIONS OF THE REGION. RUC INDICATES NO SIGNIFICANT CLEARING OF 850 MB LEVEL CEILING MOISTURE...SO SKY CONDITIONS WILL REMAIN MOSTLY CLOUDY TO CLOUDY. HOWEVER...WILL REMOVE MENTION OF RAIN FOR NE TX...LEAVE IT IN FOR EAST TX LAKES WITH FROPA PENDING. WINDS MAY LET UP SLIGHTLY BY LATER IN THE AFTERNOON...BUT HESITANT TO TAKE OUT CAUTION ON LAKES SO LEAVE ALONE. FINALLY...LOWER TEMPS A CATEGORY SOME AREAS PER CURRENT TRENDS AND VIRTUALLY NO WARMING EXPECTED. VII .SHV...NONE. la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1018 PM EDT SUN OCT 13 2002 00Z RAOBS/LATEST WV LOOP AND RUC ANAL SHOW MEAN UPR TROF OVR THE GRT LKS BTWN RIDGES OFF THE E COAST AND OVR SW CAN. A FAIRLY POTENT SHRTWV EMBEDDED WITH THE NW FLOW ALF IS DIGGING SE THRU ERN LK SUP. SCT WND PARALLEL LK EFFECT SHSN HAVE DVLPD MAILY OVR ERN LK SUP IN THE WEAKLY CYC NWLY LLVL FLOW BEHIND SFC LO PRES/COLD FNT MOVG E AHD OF THE UPR SHRTWV. H85 TEMP ABOUT -8C (LK TEMP ABOUT 10C FOR DELTA-T OF 18C) OVR THE WATER. 00Z APX SDNG INDICATES INVRN HGT H65-7...WITH VERY MOIST AIR BLO THE INVRN. REGIME HAS SWITCHED FM LAND INSTABILITY THIS AFTN TO A LK INSTABILITY REGIME TNGT WITH LOSS OF SOLAR INSOLATION...AND SCT SHSN OVR LAND TDAY HAVE DISSIPATED WITH LOSS OF HTG AND ARRIVAL OF MUCH DRIER AIR/SOMEWHAT LWR INVRN HGT ASSOCIATED WITH NVA/EXTREME 12HR H5 HGT RISES (UP TO 230M AT INL)/ SFC RDG NOW MOVG INTO WRN LK SUP IN WAKE OF SHRTWV. SFC WNDS HAVE DIMINISHED WITH APRCH OF WEAKER PRES GRADIENT...ESPECIALLY OVR LAND WHERE RADIATIONAL COOLING IS CONTRIBUTING TO HIER STABILITY. 00Z INL SDNG SHOWS VERY DRY PROFILE BLO INVRN HGT ARND H85...00Z GOES DERIVED SDNG FOR MQT INDICATES INVRN HGT ARND H8 WITH VERY DRY AIR BLO. SFC DWPTS AS LO AS 15F OVR MN ARROWHEAD THIS EVNG WITH CRYSTAL CLR SKIES. TEMP AS LO AS 28 AT IWD AND MQT NWS OFFICE AT 0130Z. A FEW WATERSPOUTS WERE OBSVD IN WHITEFISH BAY AHD OF SHRTWV UNDER HIER INVRN HGT LATE THIS AFTN. WITH ARRIVAL OF NVA/LWRG INVRN...XPCT ANY LINGERING WATERSPOUTS TO END SOON. ANOTHER POTENT SHRTWV NOTED MOVG SE THRU SW CAN...AND SCT HI CLD IN ADVANCE OF THIS SYS APRCHG NW MN. MAIN FCST CONCERNS TNGT ARE MIN TEMPS/GOING FRZ WRNG AND SHSN TRENDS IN THE E. LATEST RUC SHOWS BLDG H5-85 HGTS AND INCRSG MSLP OVR CWA TNGT IN WAKE OF SHRTWV THAT MOVES QUICKLY E OVRNGT. RUC INDICATES SFC HI PRES RDG WL REACH THE ERN CWA LATE TNGT. WITH ARRIVAL OF DRIER AIR...MORE ACYC FLOW...AND LWR INVRN HGT...XPCT LINGERING SCT SHSN OVR THE ERN ZNS TO DIMINISH BY THE EARLY MRNG HRS. LATEST RADAR TRENDS SHOW A WEAKENING OF THE LES MOVG INTO ALGER/LUCE ZNS... CONSISTENT WITH XPCTD TRENDS. MIN TEMPS SUN MRNG AS LO AS 15F UPSTREAM. ARRIVAL OF RDG AXIS...VERY DRY AIR UPSTREAM...AND LGT/VRBL WIND SHUD ALLOW MIN TEMPS OVR INTERIOR ZNS TO APRCH 15F DWPT. ALTHOUGH WARM LK WATER WL HOLD READINGS HIER NR THE LK SUP SHORE...XPCT MINS BLO FRZG AS WELL THERE GIVEN SUCH DRY AIR. GOING FRZ WRNG LOOKS ON TARGET. AFDMQT FM DAYSHIFT FOR LATER PDS: THE 12Z GFS AND ETA WERE IN REASONABLE AGREEMENT THROUGH 24 HOURS...BUT DIVERGED TO SOME EXTENT THROUGH THE REMAINDER OF THEIR FORECASTS. THE MAIN POINTS OF CONTENTION ARE THEIR HANDLING OF THE UPPER LOW PROGGED TO DESCEND TOWARD THE AREA LATE MONDAY NIGHT...AND THE DEGREE OF DEVELOPMENT WITH THE SURFACE LOW ALONG THE EAST COAST ON WEDNESDAY. THESE DIFFERENCES DO NOT HAVE A HUGE IMPACT ON OUR FORECAST...SINCE BOTH SOLUTIONS BRING A COLD FRONT AND REINFORCING SHOT OF COLD AIR INTO THE CWFA ON TUESDAY. HOWEVER...SINCE THE GFS IS A BIT STRONGER WITH THE POLAR LOW...IT BRINGS COLDER H85 TEMPERATURES AND DEEPER INSTABILITY INTO UPPER MICHIGAN. IN ADDITION...SINCE IT IS WEAKER WITH THE EAST COAST LOW...IT FAILS TO DEVELOP AS MUCH RIDGING AND ANTICYCLONIC FLOW OVER OUR AREA ON WEDNESDAY. THE GFS HAS BEEN FAIRLY CONSISTENT WITH THIS SOLUTION FOR THE PAST FEW RUNS...BUT AM NOT YET SOLD ON THIS IDEA SINCE THERE REMAINS QUITE A BIT OF DISPARITY BETWEEN THE MODELS AND THEIR RESPECTIVE SREF MEMBERS. WILL UTILIZE A BLEND OF THE ETA AND GFS...AND KEEP A FAIR AMOUNT OF UNCERTAINTY IN THE FORECAST FOR NOW. SHORT WAVE RIDGING AND RETURN FLOW WILL BE IN PLACE TOMORROW...WITH INCREASING WAA THROUGH THE DAY. WE SHOULD BE RID OF THE LAKE CLOUDS TO START THE DAY...AND DON/T EXPECT TOO MUCH OF AN INCREASE IN MID CLOUDS UNTIL LATER IN THE DAY. WITH THINGS LOOKING PROHIBITIVELY DRY FOR CU DEVELOPMENT...WILL GO WITH MOSTLY SUNNY SKIES BECOMING PARTLY CLOUDY IN THE AFTERNOON. SHORTWAVE CURRENTLY DIVING TOWARD NORTHWEST MONTANA WILL BE MAKING ITS WAY TOWARD UPPER MICHIGAN TOMORROW EVENING...WITH ISENTROPIC LIFT AND DIFFERENTIAL PVA OUT AHEAD OF IT WORKING TO GENERATE DECENT H85-H5 Q-VECTOR CONVERGENCE. HOWEVER...DUE TO THE LIMITED TIME FOR RETURN FLOW AHEAD OF THIS FEATURE...MOISTURE WILL BE MEEK...SO CHANCE FOR PCPN WILL BE LIMITED. BEST COMBINATION OF FORCING AND MOISTURE WILL BE NORTH OF LAKE SUPERIOR. WILL MAINTAIN CHANCE POPS FOR NOW...WITH BEST CHANCES OVER THE KEWEENAW AND NORTHERN COUNTIES. THINGS SHOULD BE WARM ENOUGH FOR RAIN AS THE SHORTWAVE AND ASSOCIATED COLD FRONT MOVE THROUGH MONDAY NIGHT-EARLY TUESDAY...SO WILL NOT MENTION ANY POSSIBILITY OF SNOW WITH ITS PASSAGE. COLD ADVECTION RETURNS IN EARNEST ON TUESDAY...AND PERSISTS THROUGH WEDNESDAY...WITH H85 TEMPERATURES FALLING TO AROUND -10C BY TUESDAY EVENING AND REMAINING NEAR THAT VALUE THROUGH WEDNESDAY. THE MODEL DIFFERENCES MAKE IT DIFFICULT TO PREDICT WHAT THE BOUNDARY LAYER FLOW WILL BE DURING THIS TIME FRAME...AND IT IS ALSO TOUGH TO PIN DOWN THE AMOUNT OF MOISTURE...DEGREE OF CYCLONIC FLOW...AND TIMING OF INDIVIDUAL VOT MAXES. GIVEN THE UNCERTAINTY...WILL CARRY CHANCE POPS FOR TUESDAY AND WEDNESDAY...ALTHOUGH THE GFS AND ETA BOTH SUGGEST BETTER CHANCES ON WEDNESDAY WITH DEEPER INSTABILITY AND MOISTURE PROGGED. BOUNDARY LAYER TEMPERATURES SHOULD REMAIN WARM ENOUGH FROM SOME RAIN EARLY TUESDAY...BUT THINGS SHOULD TURN COLD ENOUGH FOR ONLY SNOW BY EVENING AND REMAIN THAT WAY THROUGH WEDNESDAY. MEDIUM RANGE GUIDANCE CONTINUES TO EXHIBIT SOME DIFFERENCES IN THE THURSDAY THROUGH SUNDAY TIME FRAME...ALTHOUGH THE VARIOUS SOLUTIONS ARE IN AGREEMENT ON THE GENERAL LONGWAVE PATTERN. A HIGHLY AMPLIFIED FLOW IS PROGGED...WITH THE LONGWAVE TROUGH OVER EASTERN CANADA AND THE EASTERN CONUS...WITH RIDGING ALONG THE WEST COAST NORTHWARD INTO EASTERN ALASKA. THIS WILL WORK TO KEEP THINGS COOL ACROSS THE UPPER GREAT LAKES...WITH CHANCES FOR LAKE EFFECT PCPN GIVEN THE EXPECTED INSTABILITY...CYCLONIC FLOW AND SUFFICIENT MOISTURE. DISAGREEMENT BETWEEN THE GFS...ECMWF...CANADIAN...AND LOCAL EXTENDED ETA MAKE IT TOUGH TO GET TOO SPECIFIC IN THE FORECAST AT THIS POINT. THE GFS CONTINUES TO BE THE MOST AGGRESSIVE SOLUTION...BRINGING THE CIRCUM-POLAR VORTEX THE FARTHEST SOUTH AND PARKING IT JUST NORTH OF LAKE SUPERIOR WEDNESDAY THROUGH FRIDAY. THE OTHER GUIDANCE KEEPS THIS FEATURE FARTHER NORTH...BUT STILL KEEPS PLENTY OF COLD AIR IN THE REGION...WITH 850MB TEMPERATURES SUFFICIENTLY COLD FOR LAKE EFFECT PCPN IN ALL MODEL SOLUTIONS. THERE IS A WEAK CONSENSUS FOR BUILDING A SHORTWAVE RIDGE OVER THE AREA ON SATURDAY BEFORE SWINGING ANOTHER SHORTWAVE THROUGH ON SUNDAY. WILL GO WITH A DRY FORECAST IN THE GRIDS FOR MOST OF SATURDAY...AND CARRY CHANCE POPS ON THE OTHER DAYS. WILL GO OUT ON A LIMB AND MENTION ONLY SNOW THURSDAY AND FRIDAY GIVEN EXPECTED BOUNDARY LAYER TEMPERATURES AND 1000-850MB THICKNESSES. HOWEVER...WITH SLIGHTLY WARMER TEMPERATURES EXPECTED SATURDAY INTO SUNDAY...WILL MENTION MIXED PCPN FOR THAT TIME FRAME. WILL STICK CLOSE TO GFS MOS TEMPERATURES...BLENDING WITH EXTENDED ETA AT TIMES. .MQT...FREEZE WARNING TONIGHT MIZ001>007-009-012>014. KC mi DEEP SOUTH TEXAS FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 920 AM CDT SUN OCT 13 2002 SHORT TERM...CF HAS EDGED TO JUST N OF THE RIO GRANDE VLY NOW...WITH LATEST MSAS SFC ANALYSIS SHOWING DWPT GRADIENT HELD FURTHER NORTH...OVR CENTRAL TX. LATEST RUC AND MESOETA SUGGEST GOOD INSOLATION PRIOR TO THE ENTRY OF COOLER AIR...WITH TEMPS TO 85 MFE AND WEST...82 IN BRO PRIOR TO CAA LATER THIS PM. CURRENT ZFPBRO IS A GOOD AVERAGE OF THE DRY AND COLD AVN AND THE WET AND WARM MESOETA. THIS IS THE BEST BET ATTM...AND NO CHANGES ARE NEEDED. MARINE...BUOY020 REPORTS SEAS AT 3 FEET WITH NE FLOW AT 15 KTS. FROPA SHOULD ENTER OUR LWR TX COASTAL WATERS ARND 13/17Z TDY...WITH SCA IN EFFECT NOW FOR BOTH BAY AND OFFSHORE. ISOLD TSRA/SHRA ANTICIPATED WITH FROPA...BECMG SCT OVRNGT AS REAL LIFT AND MSTR ARRIVES. NORTH WINDS SHUD MAINTAIN THEMSELVES COLUMBUS DAY...20 TO 25 KTS W/SEAS 7 TO 9 FT. SECONDARY SURGE OF COLD AIR ON TUE KEEPS NORTH WINDS OVER MARINE ZONES...AND WILL MAINTAIN WINDS N AT 15 TO 20 WITH SEAS AT 4 TO 6 FT. SYNOPTIC-AVIATION-MARINE...PHILO (58) MESO...VEGA INTERNET ADDRESS...WWW.SRH.NOAA.GOV/BRO .BRO...SCA TODAY GMZ130-150-155-170-175. tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BLACKSBURG, VA 854 PM EDT SUN OCT 13 2002 WILL UPDATE TO TWEAK AM MINS A BIT WESTERN HALF FCST AREA...OTHERWISE ZONES REMAIN UNCHANGED. COLD FRONT EXITING FCST AREA AT 00Z. DRYING/COOLING ALNG-WEST OF MTNS SLGTLY SLOWER THAN EXPECTED...WITH UPSLOPE AREAS REMAINING SOCKED IN W/LOW ST/SC. M-ETA/RUC BOTH DRY OUT LOW LVL MSTR BY 6Z...AS HIGH RDGS NORTH OF FCST AREA...SO TREND OF OVRNGHT CLRG STILL LOOKS GOOD. TEMPS/DEWPTS SHOULD FALL OFF QUICKLY ONCE CLRG OCCRS WESTERN AREAS...BUT FEEL MON AM TEMPS ARE A TAD ON THE COOL SIDE. FCSTID = 4 ROA 46 62 43 47 / 0 0 20 90 LYH 45 60 41 47 / 0 0 10 90 DAN 47 64 44 47 / 0 0 30 90 BLF 42 58 41 48 / 0 0 20 90 LWB 40 55 35 45 / 0 0 0 90 BCB 44 59 39 47 / 0 0 20 90 TNB 42 58 38 46 / 0 0 30 90 .RNK... NC...NONE. VA...NONE. WV...NONE. va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 952 AM EDT MON OCT 14 2002 MORNING SURFACE ANALYSES INDICATE THAT THE FRONTAL BOUNDARY HAS SLIPPED A BIT FURTHER TO THE S AND E OVERNIGHT. IT NOW EXTENDS FROM COASTAL SC SW ACROSS SE AND SC GA, AND THEN ACROSS OUR FL ZONES INTO THE NRN GULF. THIS HAS ALLOWED SOMEWHAT DRIER AIR TO FILTER INTO THE REGION WITH DEW POINTS IN THE LOWER 60S ACROSS OUR NW ZONES AND PW DOWN TO ABOUT AN INCH AND A HALF ON THE 12Z KTLH SOUNDING. SO FAR, AREA RADARS INDICATE ISOLATED TS OUT IN OUR COASTAL WATERS. A SHORT WAVE TROUGH IS DEEPENING ACROSS TX THIS MORNING AND THIS WILL EVENTUALLY FORCE CYCLOGENESIS ON THE FRONTAL BOUNDARY. MODEL CONSENSUS INDICATES THIS WILL NOT HAPPEN UNTIL THIS EVENING OR TONIGHT. IN THE MEAN TIME, SOME WEAK ISENTROPIC ASCENT IS INDICATED BY THE MODELS. ETA AND AVN AGREE THAT THIS WILL BE FAIRLY WEAK TODAY AND MAINLY ACROSS OUR FAR WRN ZONES. 06Z MAV POPS HAVE COME DOWN ACCORDINGLY FROM THE 00Z NUMBERS. NGM IS THE OUTLIER SHOWING STRONGER UPGLIDE FURTHER E. LATEST RUC SUPPORTS THE ETA AND AVN SOLUTIONS. BLENDING THOSE SETS OF MOS GIVES US SOMETHING PRETTY CLOSE TO OUR CURRENT FORECAST, SO DO NOT PLAN ANY CHANGES TO POP TODAY/S FORECAST ATTM. IF AN UPDATE BECOME NECESSARY LATER ON, WILL CONSIDER ADDING HEAVY RAIN WORDING TO 2ND/3RD PERIODS. MARINE: FORECAST FOR TODAY LOOKS ON TRACK. DEPENDING ON THE EXACT TRACK OF THE SURFACE LOW, WE MAY BE LOOKING AT SCEC OR MARGINAL SCA CONDITIONS ON TUE. WOOL PREVIOUS DISCUSSION FOLLOWS. ***************************************************************** 220 AM EDT MON OCT 14 2002 SYNOPSIS: WATER VAPOR/RUC80 500-MB COMPOSITE SHOWS WEAKNESS ALOFT W/ SEVERAL WEAK S/WAVE TROUGHS...ONE OVER COASTAL GA/NE FL...ANOTHER INVOF ARKLATEX & THIRD APPROACHING TX PANHANDLE. MSAS ANALYZED A STATIONARY FRONT FROM MID-ATLANTIC COAST TO NRN FL TO NW GULF OF MEXICO. MUCH DRIER AIR DISPLACED OVER MID-SOUTH WHERE DEW POINTS WERE IN THE 30S/40S...WHILE MUGGY 60S/LOWER 70S PREVAILED OVER CWFA. WINDS ON EITHER SIDE OF FRONT WERE FROM NE 5-10 KTS. SCATTERED SHWRS/TSTMS WERE DEVELOPING ALONG/AHEAD OF FRONT FROM WRN BIG BEND COASTAL WATERS INTO PANHANDLE OFFSHORE WATERS. MODELS: LITTLE CHANGE IN MID/UPPER LEVELS. ACTIVE NRN STREAM CONTINUES W/ SERIES OF S/WAVE TROUGHS FROM NRN ROCKIES TO NEW ENGLAND. WEAKER SRN STREAM W/ MAIN S/WAVE OVER TX PANHANDLE MOVING ALONG RED RIVER VALLEY TODAY W/ AMPLIFYING TROUGH INTO LOWER MS VALLEY ON TUE. TROUGH SWINGS ACROSS THE CWFA TUE NIGHT & SITUATED OVER MID-ATLANTIC REGION ON WED. UPPER TROUGH TO W WILL INDUCE CYCLOGENESIS OVER CNTRL GULF COAST TONIGHT/TUE. DIFFERENCES NOTED AS AVN SHOWS LOW CENTERED NEAR WRN FL PANHANDLE TUE...WHILE ETA LAGS LOW FURTHER SE OVER NE GULF. NGM DISPLACES LOW WELL TO NE OF AVN/ETA. TEND TO BELIEVE THE AVN WHICH HAS HAD BETTER RUN TO RUN CONTINUITY THAN ETA/NGM. THE STALLED FRONT OVER OUR COASTAL WATERS WILL LIFT NWD TONIGHT/TUE AS LOW LIFTS NE INTO NRN GA LATE TUE & PIEDMONT REGION EARLY WED. FRONT SWEEPS THRU CWFA TUE NIGHT/EARLY WED. FOR QPF PURPOSES...RAINFALL AMOUNTS THRU 48 HRS SHOULD AVERAGE FROM A HALF TO AN INCH. HIGHER AMOUNTS ARE POSSIBLE...ESPECIALLY OVER PANHANDLE/AL ZONES IN CLOSER PROXIMITY TO SURFACE LOW. FORECAST: W/ FRONT HANGING AROUND & DAYTIME HEATING...CURRENT GOOD CHANCE POPS IN ORDER. RAIN CHANCES INCREASE BEGINNING TONIGHT W/ CATEGORICAL POPS W & LIKELY E. CATEGORICAL POPS AREAWIDE ON TUE. RAIN CHANCES DIMINISH FROM W TO E TUE NIGHT W/ FROPA. WED STILL LOOKS DRY. DID NOT STRAY FAR FROM MARINE: NE-E WINDS TODAY VEER TO S-SW ON TUE AS LOW/INVERTED TROUGH NEAR WRN PANHANDLE WATERS LIFTS NE. NO HEADLINES ANTICIPATED UNTIL LATE TUE W/ SCEC...CONTINUING THRU WED NIGHT. WINDS/SEAS GRADUALLY SUBSIDE BEGINNING THU AS HIGH PRESSURE BUILDS TO N OF WATERS. FIRE WEATHER: NO HEADLINES WITH HIGH HUMIDITIES & PRECIP CHANCES. EXTENDED (THU-SUN): NO CHANGES. A COOLER & DRIER PERIOD W/ LOWEST TEMPS OF THE EARLY FALL SEASON THUS FAR. PRELIM NUMBERS: TLH 082/068 078/062 5785 PFN 080/069 077/063 5884 DHN 078/065 072/058 5884 ABY 078/065 073/057 5785 VLD 080/067 076/060 5785= .TLH... AL...NONE. GA...NONE. FL...NONE. 08/MAJ fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DULUTH MN 1035 AM CDT MON OCT 14 2002 FORECAST FOCUS THIS AFTERNOON IS CLOUD TREND...WIND...PRECIP CHANCES CURRENT SURFACE ANALYSIS INDICATES AREA OF LIGHT RAIN/SPRINKLES MOVING EAST THROUGH CENTRAL MINNESOTA AHEAD OF FRONT. WILL KEEP ISOLATED SHOWERS ACROSS AREA THIS AFTERNOON UNDER BREEZY/WINDY CONDITIONS. WINDS WILL INCREASE AS GRADIENT TIGHTENS AS INDICATED FROM RUC. TEMPERATURES LOOK ON TRACK FOR THIS AFTERNOON. REST OF FCST FINE. .DLH...NONE. STEWART mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 1015 AM EDT MON OCT 14 2002 MINOR TWEEKS FOR 1ST PD SKY COVER AS SAT PIX SHOW CU/SC DVLPNG AND RUC PROFILES INDICATE POTNL FOR A PD OF BKN CLDS THIS AFTN ACRS PORTIONS OF CNTRL NY. HIGH SLIDES ACRS THE RGN TNGT WITH WAA BEGINNING LATE...BUT TEMPS WILL FALL RAPIDLY AFTER SS AND ALLOW FOR A WDSPRD KILLING FROST/FREEZE. ESF ISSUED FOR POTNL MIDWEEK +RA EVENT. AREAS OF NE PA RECEIVED 4-7 INCHES OF RAIN WITH LAST SYSTEM AND POTNL FOR SOME PRBLMS IF WE GET ANOTHER ROUND OF +RA. 00Z MDL RUNS WERE PEGGING THIS AREA WITH THE HEAVIEST AMTS. .BGM...FREEZE WARNING ALL ZONES TONIGHT. BRADY ny FORECAST DISCUSSION FOR EASTERN NORTH DAKOTA AND NORTHWEST MINNESOTA NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 950 AM CDT MON OCT 14 2002 FORECAST CHALLENGE FOR UPDATE CONCERNS PCPN CHANCES AND TEMPERATURES. PREFRONTAL TROUGH WORKING THROUGH NM MN WITH MAIN COLD FRONT ENTERING RED RIVER VALLEY. SHORTWAVE ALSO PUSHING THROUGH FA WITH ASSOCIATED SFC LOW OVER MANITOBA LAKES AREA AND WEAKER LOW OVER GFK. RIBBON OF -SHRA ASSOCIATED WITH LEADING EDGE OF SHORT WAVE EXITING EASTERN FA AT THIS TIME WITH WEAK RETURNS CONFINED TO NORTHERN TIER. UPSTREAM KMBX-88D AND CANADIAN RADAR LOOP INDICATING VERY LITTLE ELSE UPSTREAM IN ISENTROPIC DOWNGLIDE. BASED ON THIS...RUC INTEGRATED RH FIELDS AND CONDENSATION PRESSURE DEFICITS FROM 290K SURFACE FEEL NORTHERN AREAS LIKELY TO CONTINUE TO SEE ISOLD/WIDELY SCATTERED SHRA WITH LITTLE IF ANY ACROSS SOUTHERN 2/3 FA. WITH FALLING CONVECTIVE TEMPERATURES 18Z AND AFT AND INCREASING LOW LEVEL MOISTURE WILL LIKELY SEE SC CLOUD FIELD EXPAND ACROSS MOST OF FA THIS AFTERNOON AFTER SOME EARLY SUN. CLOUDS AND COLD ADVECTION LIKELY TO SHUT OFF TEMPERATURE RECOVERY OVER MOST AREAS. 30KTS TO MIX DOWN ONCE LOW LEVELS GO ADIABATIC AND COLD ADVECTION TAKES HOLD SO WILL CONTINUE WITH WINDY WORDING. WILL TAKE A LAST LOOK AT TEMPERATURES ALTHOUGH CURRENT FORECAST LOOKS IN PRETTY GOOD SHAPE. ANY CHANGES WILL BE MINOR. .FGF...NONE VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE/WASHINGTON 300 PM EDT MON OCT 14 2002 SHORT TERM...TONIGHT THRU TUE NIGHT ...COLD TONIGHT THEN ANOTHER SHOT OF RAIN ARRIVING LATE TUE... NCEP MODEL GUIDANCE SUITE CONTINUES TREND OF PREVIOUS RUNS WITH SOME DIFFERENCES THOUGH. LOW PRES CENTER STARTING TO DEVELOP OVER THE NRN GULF LATE THIS AFTERNOON. MDLS SOLNS BRING THIS LOW NORTHWARD BUT THE QUESTION IS HOW FAST AND HOW INTENSE. THE GAP BETWEEN THE SLOWER ETA SOLN AND THE NOW FASTER GFS (AVN) SOLN CONTINUES TO GROW. DISCUSSION WITH WITH NCEP/HPC SUGGESTS LEANING TOWARD THE GFS/CANADIAN GEM SOLN OF A FASTER TRACK FOR THE LOW. WHAT THIS MEANS IS THE LOW WILL TRACK JUST INLAND OVER THE CAROLINAS TOMORROW...TO A POSITION OVER THE CENTRAL DELMARVA REGION BY 12Z WED...AND CONTINUE MOVING NE WED AFTN. GFS TIMING OF THE LOW SUGGESTS HEAVIEST PRECIP (RAIN) POTENTIAL WILL OCCUR TUE NIGHT. RAINFALL POTENTIAL THROUGH THE SHORT TERM PORTION OF THIS FORECAST...EARLY WED...SUGGESTS THE LOW...OR NOR'EASTER...WILL PRODUCE BETWEEN ONE AND TWO INCHES MOST LOCATIONS...WITH ADDITIONAL RAINS WED MORNING. AT THIS POINT...GIVEN THE FORECAST SPEED OF MOVEMENT OF THIS SYSTEM...DO NOT SEE A NEED FOR A FLOOD WATCH. GFS POINTS TO A 4-6 HOUR PERIOD OF MODEATE TO HEAVY RAIN BAND MOVING NORTH ACROSS THE REGION TUE NIGHT...BUT AMOUNTS FROM THAT BAND WOULD BE ABOUT ONE INCH. FOR TONIGHT...HAVE TO DEAL WITH THE FROST ADVISORY. OK...FACTORS GOING FOR IT ARE THE VERY LOW DEW POINTS...CURENTLY IN THE 30S MOST LOCATIONS IN THE CURRENT ADVISORY AREA. ALSO WINDS WILL DECOUPLE THIS EVENING AS THE CENTER OF THE HIGH PASSES JUST NORTH OF THE AREA. HOWEVER...SAT IMGRY SHOWING LOTS OF HIGH CIRRUS CLOUDS MOVING INTO THE REGION FROM THE SW. THESE CLOUDS...IF SUFFICIENTLY DENSE...WOULD LIMIT THE AMOUNT OF TEMPERATURE DECREASE OVERNIGHT. IT IS DIFFICULT TO PREDICT JUST HOW THICK THE CIRRUS WILL BE. SO FOR NOW WILL KEEP THE ADVISORY GOING FOR THE EXISTING AREA AND FOCUS MORE ON THE SHELTERED VALUES AND LOCATIONS AS HAVING THE GREATEST FROST POTENTIAL. PROFILER AND RUC MDL CONTINUE TO SHOW DECREASING TREND ON WINDS...SO WL DROP SCA ON THE MARINE AREA. ON TUE...SOME SUN IN THE MORNING...THEN CLOUDS WILL BE ON THE INCREASE DURING THE DAY. HAVE SPREAD THE RAIN CHANCE FURTHER NORTHWARD AND QUICKER TO ACCOUNT FOR THE GFS FASTER SOLN. THIS BASICALLY MEANS TEMPS WILL BE QUITE COOL FOR THIS TIME OF YEAR SO TUE AND WED WILL FEEL MORE FALL-ISH. FOR TUE NIGHT....BASICALLY RAIN...HEAVY AT TIMES AND BREEZY. ONE TO TWO INCHES OR RAIN OVERNIGHT IS LIKELY. WILL BRING WINDS UP TO NEAR SCA CONDITIONS AND INTRODUCE A HEADLINE IN THE FORECAST THAT SCA MAY BE REQUIRED TUE NIGHT AND WED. SMZ LONGER TERM...(WED-MON) RAIN WILL BE ENDING BY MIDDAY WED AS SFC LOW DEPARTS QUICKLY TO THE NE. WILL GO 90% POPS EARLY WED AND THEN KEEP A CHANCE FOR THE AFTERNOON IN CASE SYSTEM IS LOWER TO DEPART THAN AVN INDICATES. ANOTHER S/W FCST TO ROTATE AROUND DEEP POLAR VORTEX OVER NRN ONTARIO. THIS PUSHES ANOTHER COLD FRONT THRU THE REGION ON FRI. ALTHOUGH AMT OF FORCING LOOKS STRONG WITH THIS FEATURE. WILL NOT INTRODUCE ANY POPS ATTM DUE TO THE FACT THAT LAST TWO FRONTS THAT HAVE MOVED THRU THE CWA HAVE COME THROUGH BASICALLY DRY. ROSA .LWX... DC...NONE. MD...FROST ADVISORY FROM 800 PM EDT UNTIL 800 AM EDT TUESDAY FOR ZONES MDZ002>004. VA...FROST ADVISORY FROM 800 PM EDT UNTIL 800 AM EDT TUESDAY FOR ZONES VAZ021...VAZ025>031...VAZ042. WV...FROST ADVISORY FROM 800 PM EDT UNTIL 800 AM EDT TUESDAY FOR ZONES WVZ048>055. MARINE...NONE. md AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTH PLATTE NE 1130 AM CDT MON OCT 14 2002 16Z SURFACE ANALYSIS REVEALING THAT THE COLD FRONT HAS NOW PASSED THROUGH THE CWA. WILL UPDATE TO REMOVE BECOMING WORDING IN REFERENCE TO THE ANTICIPATED WIND SHIFT. NORTHWEST OR NORTH WINDS SHOULD BE BREEZY SW CWA AND WINDY NE. ALSO LOWERED HIGH TEMPERATURES A COUPLE OF DEGREES ACROSS THE BOARD BASED ON CURRENT ANALYSIS AND 12Z ETA/RUC MODEL RUN. MONITORED THE POSSIBILITY OF A WIND ADVISORY NE CWA THIS MORNING...BUT AFTER INITIAL MIXING AND BRIEF SURGE JUST BEHIND THE FRONT...WINDS HAVE LEVELED OFF OR EVEN LOWERED SLIGHTLY IN SOME LOCATIONS. .LBF...NONE. 44 HAVE UPDATED ZONES FOR HIGHER WINDS BEHIND APPROACHING COLD FRONT. STRONG SUBSIDENCE AND AMPLE SUNSHINE WILL RESULT IN ADEQUATE MIXING FROM AT LEAST 800 MB. SOON AFTER 10 AM CDT...I AM ANTICIPATING WINDS TO VEER TO THE NORTHWEST AND NORTH AND INCREASE TO 20 TO 30 MPH NORTH AND 15 TO 25 MPH SOUTH. .LBF...NONE. 55 ----PREVIOUS FORECAST DISCUSSION---- 310 AM CDT MON OCT 14 2002 ...TEMPERATURES AND THE CHANCE OF PRECIP WED NIGHT ARE MAIN CHALLENGE... SFC ANALYSIS HAS SFC LOW OVER CENTRAL CANADA WITH WARM FRONT INTO DAKOTAS TRAILING COLD FRONT INTO CEN WY AND TROUGH AXIS THROUGH NE PANHANDLE. LARGE SFC HIGH COVERS EASTERN HALF OF COUNTRY. RWDN1 PROFILER SHOWING 40KT SOUTHERLY LOW LEVEL JET AHEAD OF SFC TROUGH KEEPING WINDS AND TEMPS UP ACROSS FA. IR IMAGERY NOT SHOWING MUCH IN THE WAY OF CLOUD COVER WITH THE SYSTEM COMING THROUGH THIS AM. MILES CITY WENT FROM 52F TO 58F AS FRONT PASSED THROUGH AND DROPPED BACK TO 52F THE NEXT HOUR. H5 STILL HAS US IN FAST NW FLOW WITH PATTERN NOT CHANGING MUCH THRU WEEKEND. ETA INITIALIZED QUITE WELL AND IS MODEL OF CHOICE THIS AM. FRONT PROGGED TO BE IN NW NE BY 12Z. TEMPS STAYING UP TONIGHT AND PRE FRONTAL COMPRESSION AND BASICALLY CLEAR SKIES TEMPS SHOULD RISE TO GUIDANCE BEFORE FALLING WITH FRONTAL PASSAGE. THE COOLER AIR ADVECTING BEHIND THE FRONT SEEMS TO BE LAGGING BY ABOUT 4 HOURS LOOKING AT OBS ACROSS MT. BACKDOOR FRONT ON WED NIGHT HAS SLOWED DOWN CONSIDERABLY AND SHOULD NOT PASS THROUGH FA UNTIL MID MORNING THU. WILL MOVE PRECIP INTO THU AND WITH ADVERTISED 850MB THICKNESS AND H5 THICKNESS WILL KEEP IT SNOW. DUE TO THE UNCERTAINTY OF TIMING BETWEEN AVN AND ETA WILL KEEP SCHC. WILL LOWER THU HIGH TEMPS. REMAINDER OF FORECAST LOOKS GOOD. .LBF...NONE. POWER ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 320 PM CDT MON OCT 14 2002 ...TONIGHT THROUGH THURSDAY NIGHT... MAIN FORECAST FOCUS WILL BE THE WINDS THIS EVENING...BEHAVIOR OF THE CLOSED LOW THAT WILL DROP INTO SOUTHERN ONTARIO AND ITS AFFECT ON THE FORECAST AREA...DISTURBANCES ROTATING AROUND THIS SYSTEM. CURRENT DATA ANALYSIS SHOWS A STRONG PRESSURE GRADIENT ACROSS THE FORECAST AREA. THIS IS THE RESULT OF THE INTERACTION BETWEEN SURFACE LOW PRESSURE CENTERED NEAR KINL AND HIGH PRESSURE OVER THE OHIO RIVER VALLEY. STRONG 850 MB JET /50-60 KNOTS/ COUPLED WITH THE LOW LEVELS BEING VERY UNSTABLE /GREATER THAN 9 C/KM 1000-850 MB LAPSE RATES/ AND DEEP MIXING HAVE CAUSE WINDS TO REACH ADVISORY CRITERIA ACROSS THE WIND SWEPT PORTIONS OF SOUTHEAST MINNESOTA AND NORTHEAST IOWA. AT 19Z...SUSTAINED WINDS OF 30 MPH WITH GUSTS 40 TO 45 WERE COMMON IN THIS AREA. BOTH THE ETA/RUC SHOW THE LOW LEVEL JET AND INSTABILITY CONTINUING THROUGH 21Z...THEN DECREASING BY 00Z. WILL CONTINUE WIND ADVISORY AS A RESULT. AVN/ETA IN MUCH BETTER AGREEMENT TODAY. INITIALIZATION WAS GOOD AS WELL. TONIGHT...EXPECT COLD FRONT TO PUSH THROUGH THE FORECAST AREA. STRONG FORCING ASSOCIATED WITH THE FRONTAL PASSAGE AT ALL LEVELS HAS A VERY DIFFICULT TIME SATURATING THE ATMOSPHERE. AS A RESULT...HIGH CONFIDENCE THE FORECAST AREA WILL SEE VERY LITTLE PRECIPITATION. WILL MENTION SCATTERED SPRINKLES ALONG THE NORTHERN COUNTIES WITH A 10 PERCENT CHANCE OF MEASURABLE. AS THE COLD AIR BEHIND THE FRONT MOVES IN...SATURATION OF THE LOW LEVELS LOOKS TO BE IMMINENT FOR A SHORT TIME. REASONABLE CONFIDENCE IN THIS GIVEN THE CROSS SECTIONS OF THE AVN/ETA/RUC. ALL SHOW THIS LOW LEVEL MOISTURE. SUBSIDENCE ERODES THIS MOISTURE LAYER DURING THE AFTERNOON. A DISTURBANCE ROTATES AROUND THE MAIN CLOSED 500 MB LOW OVER SOUTHERN ONTARIO. THERE IS GOOD CONFIDENCE IN THIS HAPPENING...AS THE AVN/ETA BOTH SUGGEST THIS BUT THERE ARE TIMING/STRENGTH DIFFERENCES /AVN SLOWER AND HIGHER AMPLITUDE/. NCEP-SREF /RSM AND ETA COMBO/ SHOWS A HIGH PROBABILITY /70 PERCENT/ OF 0.10 INCHES OF LIQUID SOMETIME TOWARD THURSDAY MORNING. CURRENT THINKING IS ABOUT 09-16Z TIME FRAME. THIS WOULD AGAIN SUGGEST GOOD CONFIDENCE. FORCING LOOKS PRETTY STRONG WITH THIS DISTURBANCE. MODEL QPF IS RATHER DIFFERENCE REGARDING AMOUNTS...WITH AVN 24 HOUR TOTALS IN EXCESS OF A HALF OF AN INCH. THE ETA IS MUCH MORE MODEST...PRODUCING ONLY HALF THAT AMOUNT. GIVEN ALL OF THESE FACTORS...HAVE INTRODUCED A CHANCE /LOW 50S/ BASED ON THIS TIMING. WOULD ENCOURAGE MIDNIGHT SHIFT TO INCREASE THIS CHANCE SHOULD CONFIDENCE INCREASE. PRECIPITATION TYPE WOULD BE MAINLY SNOW...WITH SOME ACCUMULATIONS ON GRASSY AREAS /SHOULD THIS COME TO FRUITION/. THERE SHOULD BE A CHANGE OVER TO RAIN ACROSS THE SOUTHERN AREAS DUE TO SURFACE TEMPERATURE. GIVEN THIS PRECIPITATION AND CLOUDS EXPECTED...UNDERCUT MOS GUIDANCE. KRC ...FRIDAY THROUGH MONDAY NIGHT... 5-DAY MRF AND ECMWF 500 MB MEAN CHARTS CONTINUE TO INDICATE A RIDGE OVER THE EASTERN PACIFIC AND A CLOSED LOW ACROSS ONTARIO. THIS PATTERN WILL CONTINUE TO BRING BELOW NORMAL TEMPERATURES TO THE REGION THROUGH THE PERIOD. SUPER ENSEMBLE 850 MB TEMPERATURE ANOMALIES ALSO INDICATE THE COOL TREND...AS FORECAST VALUES ARE GENERALLY ONE STANDARD DEVIATION BELOW NORMAL. MEX GUIDANCE LOWS LOOK TO BE SLIGHTLY TOO COOL ON FRIDAY NIGHT...AS THERMAL TROUGH PUSHES EAST. IN ADDITION...CLOUDS WILL BE FOUND OVERHEAD IN ADVANCE OF AN APPROACHING WAVE. WILL ADJUST LOWS UPWARD OVERNIGHT FRIDAY. BY SATURDAY EVENING...ANOTHER COLD FRONT WILL PUSH THROUGH THE REGION...KEEPING TEMPERATURES BELOW NORMAL. WILL NOT ADD ANY PRECIPITATION CHANCES THROUGH THE PERIOD. THE OPERATIONAL MRF RUN DOES NOT PRODUCE ANY SIGNIFICANT PRECIPITATION. THIS AGREES WITH THE MRF ENSEMBLE MEMBERS WHICH GENERALLY SHOW A 20 PERCENT CHANCE OR LESS OF 0.10 INCH AMOUNTS THROUGH MONDAY. SAW .LSE...WIND ADVISORY THROUGH 5 PM CDT /22Z/ THIS AFTERNOON SOUTHEAST MINNESOTA...MNZ086-087-094-095 NORTHEAST IOWA........IAZ008-009-018-019. KRC wi