AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE EUREKA CA 100 PM PST MON DEC 6 2004 .SYNOPSIS...A COLD FRONT WILL APPROACH NORTHWESTERN CALIFORNIA THIS AFTERNOON. STRONG SOUTH WINDS WILL INCREASE THIS AFTERNOON AHEAD OF THE FRONT. AS THE FRONT MOVES INLAND TONIGHT...EXPECT PERIODS OF RAIN...WITH SNOW AT HIGHER ELEVATIONS. THIS WET PATTERN WILL CONTINUE THROUGH WEDNESDAY AS SNOW LEVELS GRADUALLY INCREASE. && .DISCUSSION...UPDATED ALL WINTER PRODUCTS AND ZONES THIS MORNING TO ACCOUNT FOR LATEST DATA. SYSTEM APPEARS TO BE BEST HANDLED BY GFS GUIDANCE. BUT THIS...ALONG WITH ALL OTHER GUIDANCE AND OBSERVATIONS...SUPPORTS HIGHER SNOW LEVELS THIS AFTERNOON AND EVENING OVER WESTERN PART OF THE CWA...AND MENDOCINO COUNTY. SPOTTER REPORTS IN TRINITY COUNTY INDICATE SNOW LEVEL RISING SLOWLY FROM AROUND 2K FEET...AND SNOW LEVELS OVER MOST OF INTERIOR MENDOCINON AND NORTHCOAST INTERIOR AROUND 4K FT AND RISING. WITH SURFACE LOW STILL ON TRACK TO PUSH ACROSS THE NORTH END OF ZONE 1...HAVE RE-ISSUED THE WIND ADVISORY FOR ALL COASTAL AREAS AS WELL AS NORTHCOAST INTERIOR. VERIFICATION WILL PROBABLY BE SPOTTY. BUT AN ADVISORY SEEMS PRUDENT WITH THE POSSIBILITY OF THE LOW BEING A BIT LOWER THAN FORECAST...OR FARTHER NORTH AS INDICATED BY THE ETA GROUP. NO UPDATES MADE BEYOND TODAY AND THIS EVENING PERIOD. && .PREVIOUS DISCUSSION...HAVE ISSUED A WINTER STORM WARNING FOR SNOW FOR THE NORTH COAST INTERIOR AND UPPER TRINITY...AND A SNOW ADVISORY FOR THE MENDOCINO INTERIOR. A STRONG AND WET COLD FRONT WILL MOVE ACROSS NORTHWEST CALIFORNIA THIS AFTERNOON AND EVENING. SNOW LEVELS WILL BE 3000 TO 4000 FEET. USED THE GFS AS GUIDANCE AS THE ETA MODEL HAS NOT BEEN DOING WELL WITH THE SERIES OF WEATHER SYSTEM. A LOW WILL DEVELOP ON THE FRONTAL BOUNDARY TODAY. THIS LOW WILL MOVE ONSHORE NEAR CRESCENT CITY LATE THIS AFTERNOON...BRING THE COLD FRONT WITH IT. THERE IS PLENTY OF MOISTURE AHEAD OF THE FRONT...SO AS SIGNIFICANT AMOUNT OF SNOW FALL IS POSSIBLE ABOVE ABOVE 3500 FEET..EXPECTING 9 TO 12 INCHES. THESE WILL BE LESS MOISTURE FURTHER SOUTH...SO HAVE ISSUED AN ADVISORY FOR SNOW ACCUMULATIONS OF 4 TO 6 INCHES ABOVE 3500 FEET. FOR TUESDAY THERE WILL BE PERIODS OF RAIN OR SNOW AS A WEAK DISTURBANCE MOVES OVER THE REGION. WEDNESDAY THE NEXT FRONTAL SYSTEM MOVES OVER THE REGION BRINGING RAIN. THE SNOW LEVELS IN NORTHERN DEL NORTE COUNTY WILL NE NEAR 5000 FEET...INCREASING TO NEAR 6000 FEET IN SOUTHERN MENDOCINO COUNTY. THIS WARMING WILL MELT MUCH OF THE SNOW THAT ACCUMULATED FROM THE PREVIOUS STORM..ADDING TO THE RUNOFF IN THE WATERSHEDS...AS THE MODELS CURRENTLY INDICATE THIS SYSTEM WILL ALSO BE VERY WET. IT APPEARS THAT THIS SYSTEM HAS SOME TROPICAL INFLUENCE THAT WAS ENTRAINED INTO THE MID LATITUDES FROM THE RECENT WESTERN PACIFIC TYPHOON. IN THE EXTENDED PERIOD...THURSDAY THROUGH SATURDAY...LINGERING POST FRONTAL SHOWERS. FRIDAY THROUGH SUNDAY...RIDGING BUILDS INTO NORTHERN CALIFORNIA SHIFTING THE STORM TRACK FURTHER NORTH. THIS WILL KEEP THE PRECIPITATION CHANCES NORTH OF KLAMATH. SUNDAY THE MODELS INDICATE ANOTHER SYSTEM WILL MOVE INTO NORTHWEST CALIFORNIA. && MARINE/WIND DISCUSSION... VERY TRICKY WIND FORECASTS THIS MORNING. GFS, WHICH HAS BEEN THE MODEL OF CHOICE LATELY, HAS CONTINUED TO WEAKEN THE SURFACE LOW PROGGED FOR ARRIVAL THIS AFTERNOON AND KEPT THE TRACK OVER THE ORCA BORDER...AND AT THIS TIME THE 06Z GFS DEPICTS THIS LOW AT 994MB. OVERNIGHT SATELLITE PICTURES INDICATE THAT THE THE UPPER LOW IS MOVING VERY RAPIDLY TOWARD THE COAST AND MAY BE A GOOD 3-4 HOURS FASTER THAN THE 00Z GFS INDICATES. 06Z ETA 12 CARRIES A COMPLETELY DIFFERENT SOLUTION SHOWING A 987MB LOW MOVING INTO THE NORTH COAST OF OREGON WHILE THE RUC IS MORE INLINE WITH THE GFS. PHONE COORDINATION WITH MFR LEAD TO GOING WITH THE GFS SOLUTION. THE BOTTOM LINE IS THAT THIS LOW WILL BRING WINDY CONDITIONS THE COAST AND COASTAL INLAND AREAS WARRANTING A WIND ADVISORY FOR ZONES 2 AND 3...AND GALE WARNINGS FOR THE SOUTHERN WATERS. && .EKA WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UPPER TRINITY RIVER. WIND ADVISORY FOR REDWOOD COAST...NORTH COAST INTERIOR...AND MENDOCINO COAST. GALE WARNING AND HAZARDOUS SEAS WARNING PT ST GEORGE TO PT. ARENA OUT 60NM $$ TJADEN/KENNEDY/TONKIN PLEASE VISIT US AT WWW.WEATHER.GOV/EUREKA (ALL LOWER CASE) ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EUREKA CA 400 AM PST MON DEC 6 2004 .SYNOPSIS...A COLD FRONT WILL APPROACH NORTHWESTERN CALIFORNIA THIS AFTERNOON. AHEAD OF THE FRONT...THE WINDS WILL BE SOUTHERLY WITH GUSTS TO 30 MPH. AS THE FRONT MOVES IN LAND...TONIGHT...EXPECT PERIODS OF RAIN...AND SNOW AT THOSE LOCATIONS ABOVE THIRTY FIVE HUNDRED FEET. THE HEAVIEST RAIN WILL BE ALONG THE COAST. THIS WET AND COLD PATTERN WILL CONTINUE THROUGH WEDNESDAY WITH GRADUALLY INCREASING SNOW LEVELS. && .DISCUSSION...HAVE ISSUED A WINTER STORM WARNING FOR SNOW FOR THE NORTH COAST INTERIOR AND UPPER TRINITY...AND A SNOW ADVISORY FOR THE MENDOCINO INTERIOR. A STRONG AND WET COLD FRONT WILL MOVE ACROSS NORTHWEST CALIFORNIA THIS AFTERNOON AND EVENING. SNOW LEVELS WILL BE 3000 TO 4000 FEET. USED THE GFS AS GUIDANCE AS THE ETA MODEL HAS NOT BEEN DOING WELL WITH THE SERIES OF WEATHER SYSTEM. A LOW WILL DEVELOP ON THE FRONTAL BOUNDARY TODAY. THIS LOW WILL MOVE ONSHORE NEAR CRESCENT CITY LATE THIS AFTERNOON...BRING THE COLD FRONT WITH IT. THERE IS PLENTY OF MOISTURE AHEAD OF THE FRONT...SO AS SIGNIFICANT AMOUNT OF SNOW FALL IS POSSIBLE ABOVE ABOVE 3500 FEET..EXPECTING 9 TO 12 INCHES. THESE WILL BE LESS MOISTURE FURTHER SOUTH...SO HAVE ISSUED AN ADVISORY FOR SNOW ACCUMULATIONS OF 4 TO 6 INCHES ABOVE 3500 FEET. FOR TUESDAY THERE WILL BE PERIODS OF RAIN OR SNOW AS A WEAK DISTURBANCE MOVES OVER THE REGION. WEDNESDAY THE NEXT FRONTAL SYSTEM MOVES OVER THE REGION BRINGING RAIN. THE SNOW LEVELS IN NORTHERN DEL NORTE COUNTY WILL NE NEAR 5000 FEET...INCREASING TO NEAR 6000 FEET IN SOUTHERN MENDOCINO COUNTY. THIS WARMING WILL MELT MUCH OF THE SNOW THAT ACCUMULATED FROM THE PREVIOUS STORM..ADDING TO THE RUNOFF IN THE WATERSHEDS...AS THE MODELS CURRENTLY INDICATE THIS SYSTEM WILL ALSO BE VERY WET. IT APPEARS THAT THIS SYSTEM HAS SOME TROPICAL INFLUENCE THAT WAS ENTRAINED INTO THE MID LATITUDES FROM THE RECENT WESTERN PACIFIC TYPHOON. IN THE EXTENDED PERIOD...THURSDAY THROUGH SATURDAY...LINGERING POST FRONTAL SHOWERS. FRIDAY THROUGH SUNDAY...RIDGING BUILDS INTO NORTHERN CALIFORNIA SHIFTING THE STORM TRACK FURTHER NORTH. THIS WILL KEEP THE PRECIPITATION CHANCES NORTH OF KLAMATH. SUNDAY THE MODELS INDICATE ANOTHER SYSTEM WILL MOVE INTO NORTHWEST CALIFORNIA. && MARINE/WIND DISCUSSION... VERY TRICKY WIND FORECASTS THIS MORNING. GFS, WHICH HAS BEEN THE MODEL OF CHOICE LATELY, HAS CONTINUED TO WEAKEN THE SURFACE LOW PROGGED FOR ARRIVAL THIS AFTERNOON AND KEPT THE TRACK OVER THE ORCA BORDER...AND AT THIS TIME THE 06Z GFS DEPICTS THIS LOW AT 994MB. OVERNIGHT SATELLITE PICTURES INDICATE THAT THE THE UPPER LOW IS MOVING VERY RAPIDLY TOWARD THE COAST AND MAY BE A GOOD 3-4 HOURS FASTER THAN THE 00Z GFS INDICATES. 06Z ETA 12 CARRIES A COMPLETELY DIFFERENT SOLUTION SHOWING A 987MB LOW MOVING INTO THE NORTH COAST OF OREGON WHILE THE RUC IS MORE INLINE WITH THE GFS. PHONE COORDINATION WITH MFR LEAD TO GOING WITH THE GFS SOLUTION. THE BOTTOM LINE IS THAT THIS LOW WILL BRING WINDY CONDITIONS THE COAST AND COASTAL INLAND AREAS WARRANTING A WIND ADVISORY FOR ZONES 2 AND 3...AND GALE WARNINGS FOR THE SOUTHERN WATERS. && .EKA WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING NORTH COAST INTERIOR AND UPPER TRINITY RIVER. SNOW ADVISORY FOR MENDOCINO INTERIOR. WIND ADVISORY FOR NORTH COAST INTERIOR AND MENDOCINO COAST. HAZARDOUS SEAS WARNING AND SMALL CRAFT ADVISORY FOR WIND PT ST GEORGE TO CAPE MENDOCINO OUT 60 NM. GALE WARNING AND HAZARDOUS SEAS WARNING CAPE MENDOCINO TO PT. ARENA OUT 60NM $$ KENNEDY/TONKIN PLEASE VISIT US AT WWW.WEATHER.GOV/EUREKA (ALL LOWER CASE) ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 250 PM EST MON DEC 6 2004 ...MED RANGE GUIDANCE SHOWING A TREND TOWARD A SIGNIFICANT COOL DOWN NEXT WEEK... .DISCUSSION... CURRENTLY...A FEW LUMPS OF DIURNAL CU OVER THE ERN/SRN PENINSULA. ALSO...CI DEBRIS STREAMING ACROSS THE STATE THANKS TO A LARGE AREA OF CONVECTION OVER THE SRN PLAINS/LWR MS VALLEY. OTHER THAN THAT... LCL AIRMASS IS QUIET AND DRY. SERLY WINDS ARE KEEPING SFC DEWPOINTS IN THE U50S/M60S...BUT RUC40 ANALYSIS INDICATES THE H100-H50 MEAN RH VALUES REMAIN AOB 70%. TONIGHT...ANOTHER QUIET NIGHT IN STORE FOR THE E FL PENINSULA AS THE RIDGE SFC-H50 RIDGE AXIS OVER THE REGION REMAINS IN CONTROL OF THE LCL WX PATTERN. THE SFC-H70 LYR IS CAPPED AND TOO DRY TO SUPPORT CONVECTION. MEANWHILE THE COMBINATION OF LIGHT SRLY FLOW...CI DEBRIS AND SFC DEWPOINTS IN THE 60S WILL KEEP MIN TEMPS A GOOD 10F DEG ABV CLIMO. TUE-THU...THE SRN PLAINS SHORT WAVE TROUGH AND ATTENDANT SFC LOW WILL RIDE THE STRONG ST JET NEWD THROUGH THE OH VALLEY AND GREAT LAKES TUE/TUE NIGHT. WEAK SFC FRONT WHICH HAD PREV BEEN PROGGED TO MOVE INTO FL AND STALL EARLY WED NOW LOOKS AS IF IT WILL STALL NORTH OF THE STATE BY 12Z WED. WEAK H50 TROUGHING WILL REDEVELOP OVER THE SRN PLAINS WED-THU WITH DOWNSTREAM RIDGING OVER FL/ADJACENT SW ATLC DEVELOPING. THIS WILL CAUSE SFC HIGH OVER THE ERN/SERN STATES TO STRENGTHEN...LEADING TO CONTINUATION OF RAIN-FREE WX WITH WARM TEMPS AVGING A GOOD 10F ABOVE CLIMO FOR EARLY DEC. FRI-MON...BIG PICTURE - EERILY GOOD AGREEMENT BTWN THE 06/00Z ECM AND 06/06Z RUNS OF THE GFS/DGEX AT BOTH THE SFC AND H50 THRU H168 SHOWING THE LONG WAVE PATTERN OVER NOAM TRENDING TWD AMPLIFICATION (I.E STRONGER POS PHASE OF PNA /PACIFIC-NOAM/ TELECONNECTION). EVEN THOUGH H50 HEIGHTS SLOWLY FALL OVER THE WRN CONUS DUE TO THE RIDGE WEAKENING SOME AND A CUTOFF LOW MOVING TWD THE PAC NW...H50 HEIGHTS ACTUALLY RISE 30-40M ON AVERAGE OVER A LARGE PART OF WRN CANADA... WHICH RESULTS IN MORE MERIDIONAL (N TO S) INTO THE CTRL CONUS. THIS WOULD PORTEND A MORE SIGNIFICANT COLD SHOT FOR THE SERN CONUS/FL IN THE DAY 7-10 PERIOD. SHOULD THE PATTERN LOCK IN FOR A TIME...IT COULD SPELL A CHILLY LATTER HALF OF DEC. DETAILS - SFC/DLM RIDGE OVER FL/ADJACENT ATLC THU WILL BEGIN TO WEAKEN AND RETREAT EWD THU NIGHT THRU FRI. SRN PLAIN SHORT WAVE TROUGH WILL SHEAR OUT AS SIGNIFICANT ENERGY DIVES SEWD INTO THE NRN STREAM...CARVING OUT A STRONG HIGH AMPLITUDE TROUGH OVER THE ERN CONUS. ASCD CLIPPER TYPE SFC LOW SWEEPS EWD ACROSS THE GREAT LAKES/NERN CONUS FRI-SAT AND DRIVES A COLD FRON THRU FL FRI NIGHT EARLY SAT. PREFRONTAL MOISTURE LOOKS SUFFICIENT TO PRODUCE BAND OF SHRA LATE FRI-FRI NIGHT AND PSBLY LINGER NEAR LAKE OKEE FOR AN HR OR SO EARLY SAT MORNING. BASED UPON WHAT HAS TAKEN PLACE WITH FROPAS THUS FAR...NOT SOLD THAT THERE WILL BE MUCH IN THE WAY OF TS. ALSO...TIMING IS CLOSE ENOUGH TO STRADDLING 00Z SAT SO THAT A 3-6HR CHG IN ONSET OF PRECIP COULD MAKE 12HR POPS MUCH HIGHER OR LOWER NORTH AND/OR SOUTH DURING THOSE TWO PERIODS. && .MARINE...SFC RIDGE AXIS WILL REMAIN OVER THE ATLC THRU WED. S-SW WINDS WILL INCREASE AS THE RIDGE RETREATS EWD WITH SCEC CONDS DEVELOPING EARLY SAT. SCA WINDS/SEAS BEHIND THE FROPA SAT NIGHT-SUN MORNING...WITH BRIEF SURGE OF SEAS BUILDING TO 8FT OR SO IN THE GULF STREAM IN STRONG NNW-N FLOW. && .PRELIMINARY POINT TEMPS/POPS... DAB 63 82 63 81 / 0 0 0 10 MCO 63 83 63 84 / 0 0 0 10 MLB 66 82 66 82 / 0 0 0 10 VRB 66 82 64 83 / 0 0 0 10 && .MLB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...BRAGAW LONG TERM...CRISTALDI fl AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 540 PM EST MON DEC 6 2004 .SHORT TERM... PATTERN THROUGH THE SHORT TERM REMAINS QUITE UNSETTLED WITH AT LEAST TWO SYSTEMS SLATED TO AFFECT THE SE U.S. WITH STRONG SOUTHERN STREAM. EACH SYSTEM HAS LIMITED POTENTIAL TO BRING TSRA TO THE CWA...WITH THE BEST THREAT FOR TSRA LATE THU-EARLY FRI. A BIGGER CONCERN IN THE SHORT TERM IS PERSISTENT RAIN ACROSS THE NW...LEADING TO RIVER FLOOD THREAT. ISENTROPIC LIFT PATTERN EXITING THE AREA THIS AFTERNOON...WITH BEST AREA OF RAIN MOVING FURTHER NORTH INTO TN. WEAK WEDGE REMAINS IN PLACE ACROSS THE NORTHEAST...NORTH CENTRAL...AND EAST CENTRAL...AND WILL BE SLOW TO ERODE WITH LOW SUN ANGLE KEEPING CLOUDS AND LOW-LEVEL MOISTURE IN PLACE. FURTHER SOUTH...UPPER RIDGE OVER FL HAS AMPLIFIED AND PUT A CAP ON SHRA DEVELOPMENT SOUTH OF I-20. NEXT PROBLEM IS DENSE FOG. OVERNIGHT...WARM/DRY SECTOR CONTINUES TO SPREAD SLOWLY NORTH...BUT EXPECT WEAK WEDGE TO REMAIN IN PLACE NE/E. WIDESPREAD VISIBILITIES OF 1/2 MILE OR LESS THROUGH MUCH OF THE AREA BOUNDED BY FFC-ATL-AHN. HAVE ISSUED A DENSE FOG ADVISORY TO COVER THIS SITUATION AS WELL. APPROACHING SHORT WAVE AND GOOD INSTABILITY WILL RESULT IN DEVELOPMENT OF A LINE OF SHRA/TSRA ACROSS THE MID-SOUTH OVERNIGHT...WHICH SHOULD REACH THE NW CORNER OF THE CWA AROUND SUNRISE. THE ACTIVITY WILL SHRINK IN AERIAL COVERAGE AND INTENSITY AS IT MOVES SE THROUGH THE CWA DURING THE DAY TUE. ISOLD TSRA CAN BE EXPECTED...BUT THE THREAT GREATLY DIMINISHES AS THE DAY PROGRESSES. LARGE AREA OF VERY DRY AIR SPREADS ACROSS THE CWA FOR WED...BUT IT WILL BE VERY BRIEF. && .LONG TERM... IT APPEARS THAT A SIGNIFICANT PATTERN CHANGE...POTENTIALLY TO A PACIFIC...NORTH AMERICAN TELECONNECTION...IS FORTHCOMING...WHICH WILL RESULT IN MUCH COLDER WEATHER FOR THE EASTERN U.S...INCLUDING THE SE...BY THE WEEKEND AND EARLY NEXT WEEK. IT ALSO APPEARS THAT THIS PATTERN WILL BE FAIRLY LONG LIVED AS ADDITIONAL SHORT WAVES DIVING SOUTH FROM ALBERTA KEEP A BROAD LONG WAVE TROUGH CARVED OUT OVER THE EASTERN U.S. THROUGH THE WEEK. HOWEVER...THE TRANSITION FROM THE CURRENT PATTERN TO THE PNA PATTERN APPEARS TO FEATURE A SIGNIFICANT THREAT OF ADDITIONAL SHRA AND SOME TSRA. AT LEAST TWO SHORT WAVES WILL TRAVERSE THE AREA LATE THU THROUGH FRI. UNFORTUNATELY...THERE IS THE THREAT OF ADDITIONAL HEAVY RAIN ACROSS THE NORTHWEST DURING THIS PERIOD. THIS WILL NEED TO BE CLOSELY MONITORED BY LATER SHIFTS. EACH RUN OF THE MODELS INDICATES AN INCREASING THREAT OF SHRA/TSRA IN THE THU-FRI PERIOD...WHICH IS CONSISTENT WITH A MAJOR PATTERN CHANGE. UNTIL LATE IN THE WEEK...UNSEASONABLY WARM TEMPERATURES WILL CONTINUE. THE COOLING TREND WILL COMMENCE FRI NIGHT...THEN OVERALL BECOME PROGRESSIVELY COLDER THROUGH EARLY NEXT WEEK UNTIL HIGHS DROP INTO THE 40S AND LOWS FALL IN THE 20S BY DAY 7 AND 8. && .HYDROLOGY... RAINFALL OF 1.0 TO 1.5 INCH FELL ACROSS MUCH OF THE NORTHWEST LAST NIGHT AND RAIN PERSISTS IN THOSE AREAS TODAY. SEVERAL CREEKS AND RIVERS ACROSS THE NORTH ARE NEAR FLOOD STAGE. ADDITIONAL HEAVY RAIN WILL SIMPLY AGGRAVATE THE SITUATION. PLAN TO ISSUE AN FFA FOR THE FAR NORTHWEST AND NORTH CENTRAL AREAS THROUGH 18Z TUE...MAINLY FOR CREEK...STREAM...AND RIVER FLOODING. && .AVIATION... WARM FRONT ASSOCIATED WITH IN-SITU WEDGE NOW LIES FROM NEAR KCCO TO 20NM S OF KAHN. EAST TO NORTHEAST WINDS AND IFR CONDITIONS PREVAIL NORTH OF THE WARM FRONT. THIS FRONT SHOULD LIFT NORTH TONIGHT... HOWEVER MODELS (EVEN 18Z ETA12) DOING POORLY WITH THIS FEATURE. PREFER RUC MODEL BUT MAY HAVE TO SLOW DOWN NORTHWARD PROGRESSION OF WARM FRONT AND IMPROVING CIGS/VSBYS. FOR KATL BELIEVE SOUTHEAST WINDS AND MVFR CONDITIONS TO RETURN AFTER 5Z. NEW 18Z MAV GUIDANCE HAS WIND SHIFT THIS EVENING BUT KEEPS CIGS/VSBYS DOWN TO THE FLOOR AT KATL. WILL MONITOR CLOSELY. && .PRELIMINARY POINT TEMPS/POPS... ATLANTA 50 65 46 64 / 40 60 00 10 ATHENS 49 63 48 64 / 10 60 00 10 GAINESVILLE 47 63 46 62 / 40 60 00 10 ROME 50 63 43 65 / 90 60 00 10 COLUMBUS 54 74 51 71 / 10 40 00 10 MACON 52 75 52 69 / 10 40 00 10 && .FFC WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH FOR EXTREME NORTHWEST AND NORTH CENTRAL AREAS THROUGH 1 PM EST TUE. DENSE FOG ADVISORY FOR NORTHEAST...NORTH CENTRAL...AND EAST CENTRAL AREAS THROUGH 6 AM EST. && $$ RAB/SNELSON ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1215 PM CST MON DEC 6 2004 .DISCUSSION... UPDATED THE FORECAST TODAY TO REMOVE MORNING FOG AND TO ELEVATE HIGHS ACROSS SE IL. ALSO REFINED RAIN CHANCES SOUTH OF I-72 TO SLIGHT CHANCE LATE THIS AFTERNOON. OTHERWISE A CLOUDY AND MILD AFTERNOON WITH HIGHS RANGING FROM THE MID 50S FROM PEORIA AND BLOOMINGTON NORTH TO 60 TO 65 DEGREES ACROSS SE IL. NOON SURFACE ANALYSIS HAS 1003 MB LOW PRESSURE OVER MT WITH A WARM FRONT OVER NORTHERN IA AND FAR NORTHERN IL/IN. ANOTHER LOW PRESSURE WAS GETTING ORGANIZED OVER THE FAR WESTERN OK PANHANDLE WITH PRESSURE DOWN TO 1004 MB. ITS WARM FRONT WAS OVER CENTRAL PARTS OF AR/TN. CENTRAL AND SE IL IN A MILD/MOIST SOUTH FLOW WITH CLOUDY SKIES. LOW CEILINGS AND VISIBILITIES HAVE BEEN GRADUALLY RISING THIS MORNING. TEMPS RANGE FROM 50 TO 57 DEGREES WITH THE MILDEST READINGS OVER SE IL AT LAWRENCEVILLE AND COOLEST NW IL AT GALESBURG. HIGH DEWPOINTS IN THE LOWER 50S. RUC AND ETA KEEP CENTRAL/SE IL DRY THROUGH 03Z/9 PM WITH QPF SW OF AREA. BUT KEPT SLIGHT CHANCE OF LIGHT RAIN SHOWERS SOUTH OF I-72 LATE THIS AFTERNOON AFTER 21Z WITH ISENTROPIC LIFT BEGINNING THEN AND ATMOSHPERE SO MOIST ALREADY. COULD GET A FEW PEEKS OF SUNSHINE THIS AFTERNOON THROUGH THIN SPOTS IN THE OVERCAST ESPECIALLY SOUTH AND LIKED WARMER ETA HIGHS 55 NORTH AT GALESBURG AND CLOSE TO 65 AT LAWRENCEVILLE. LOW PRESSURE TO MOVE TOWARD THE OZARKS THIS EVENING AND LIFT A WARM FRONT NORTH TOWARD I-72 BY MIDNIGHT. RAIN CHANCES INCREASE THIS EVENING FROM THE SOUTH WITH NEAR 100% CHANCES OF RAIN OVERNIGHT AND COULD BE HEAVY AT TIMES WITH EMBEDDED THUNDERSTORMS AS LOW PRESSURE MOVES INTO CENTRAL IL BY DAWN TUE. SPC LIFTED SLIGHT RISK OF SEVERE THUNDERSTORMS LATE THIS EVENING AND OVERNIGHT FROM I-70 NORTH TOWARD CHARLESTON/MATTOON AREA WITH DAMAGING WIND GUSTS MAIN SEVERE WEATHER THREAT FROM 10 PM TO 4 AM. MODERATE RISK STILL JUST SOUTH OF KY. && .PREV DISCUSSION... WARM FRONT SLOWLY SHIFTING NORTHWARD THROUGH IL AREA THIS MORNING...06Z SFC MAP HAD FRONT ROUGHLY FROM KUIN TO KMTO. PLENTY OF LOW LEVEL MOISTURE BEHIND WARM FRONT...SO EXPECT CLOUDS TO STICK AROUND TODAY...AND KEPT THE MENTION OF MORNING FOG. NEXT STORM SYSTEM W OF SRN CAL...WITH 50H LOW JUST W OF SAN DIEGO AT 00Z. FORECAST CHALLENGE IN THE SHORT TERM WILL BE HIGHS TODAY AND LOWS TONIGHT. SHORT TERM...TODAY THROUGH WEDNESDAY... LOW PRESSURE OVER SW US...WILL SLIDE TOWARD THE AREA TODAY. WARM AND MOIST AIR IN PLACE IN THE LOWER MS RVR VALLEY...WITH 60 DEW PTS HITTING THE MO BOOTHEEL. SOUTH WINDS AHEAD OF THE LOW WILL NUDGE THIS AIRMASS CLOSER TO THE AREA TODAY. ETA TEMP GUIDANCE SUGGESTING LOWER TO MIDDLE 60S AS HIGHS TODAY...HOWEVER THINK THEY ARE A LITTLE WARM DUE TO THE LACK OF SUN TODAY. OTHER MODEL GUIDANCE COOLER WITH LOWER 60S SE AND MIDDLE 50S ELSEWHERE. WL SPLIT THE DIFFERENCE. THE ETA AND GFS STILL DISAGREE ON THE EXACT TRACK OF THIS INTO IL TONIGHT. ETA IS A LITTLE SLOWER AND STRONGER WITH THE SFC LOW THAN THE GFS...AND THE ETA IS CONSISTENT WITH PREV MODEL RUNS IN TRACKING LOW OVER CENT IL. THE GFS ON THE OTHER HAND HAS A MORE BROAD AREA OF SFC LOW PRESSURE...WITH QPF MAX NR THE OH RVR. WL LEAN MORE TOWARD THE ETA SOLUTION. WITH K INDEX VALUES IN THE LOWER 30S AND SOME CAPE ON THE ETA MODEL SOUNDINGS ACROSS THE FORECAST AREA...WL MENTION SLIGHT CHANCE OF THUNDER IN ALL BUT THE NW TONIGHT. THE SPC DY1 OUTLOOK CLIPS THE SE PORTION OF OUR CWA TONIGHT. THIS SYSTEM WILL MOVE OUT RATHER QUICKLY TUE...ALLOWING HIGH PRESSURE TO RETURN LONG TERM...THURSDAY THROUGH SUNDAY... NEXT STORM STILL LOOKS ON TRACK FOR THU AND FRI. THE UKMET AND GFS IN FAIR AGREEMENT WITH TIMING...ALTHOUGH GFS A TAD QUICKER. TEMPERATURE-WISE...STILL GOING SLIGHTLY COOLER THAN GUIDANCE...WITH A SLOW COOLING TREND THROUGH NEXT WEEKEND. && .ILX WATCHES/WARNINGS/ADVISORIES... .IL...NONE. && $$ HUETTL/KELLY il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 100 PM EST MON DEC 6 2004 .AVIATION... IFR-LIFR CONDITIONS JUST NORTH OF FRONT/WINDSHIFT SHIFTING NORTH ACROSS CWA. FRONT WILL GRADUALLY WORK NORTH THIS AFTERNOON BRINGING IMPROVING CONDITIONS LATER THIS AFTERNOON INTO THIS EVENING. NEXT STRONG UPPER TROF SFC LOW TO BEGIN TO AFFECT TAF SITES LATER TONIGHT WITH RAIN AND IFR CIGS MOVING IN BY MIDNIGHT AND CONTINUING INTO THE FIRST HALF OF TUE. SOME LIFR CONDITIONS AGAIN EXPECTED WITH THUNDER ALSO POSSIBLE LATE TONIGHT AT BOTH KSBN AND KFWA BUT BEST CHC APPEARS TO BE KFWA AND ADDED TEMPO THERE. SOUTH WINDS WILL INCREASE AHEAD OF SYSTEM TONIGHT. APPEARS STRONG NORTHWEST WINDS BEHIND SFC LOW WILL WAIT UNTIL NEAR END OF TAF PERIOD AND DID NOT INCLUDE IN THIS TAF PACKAGE. && .UPDATE... UPDATE EARLY THIS MORNING TO REMOVE RAIN FROM NORTHEAST CWA AND INCLUDE DRIZZLE AND FOG ACROSS CWA INTO MID MORNING THEN CLOUDY THROUGH AFTERNOON. ALSO BUMPED UP MAX TEMPS A COUPLE DEGREES BASED ON CURRENT READINGS AND TEMPS UPSTREAM. && .PREVIOUS DISCUSSION... TODAY AND TONIGHT ISSUES AGAIN WITH MODEL PREFERENCE. OPERATIONAL GFS 24 HOURS AGO HAD TRENDED IN RIGHT DIRECTION BUT NOW TOO FAR SOUTHEAST WITH SURFACE LOW AT 12Z TUESDAY. ETA WAS THE OUTLIER 24 HOURS AGO AND NOW APPEARS TO HAVE BETTER HANDLE ON ENERGY TO LIFT OUT OF SOUTHERN AZ. ETA HARD TO BEAT WITH NGM/20KM DEV RUC AGREEMENT AND EVEN SEVERAL GFS ENSEMBLE MEMBERS LEANING FURTHER NORTHWEST AS WELL. ECMWF/UKMET IN BETWEEN BUT AT LEAST TRACKING SURFACE LOW THROUGH FORECAST AREA. FIRST ISSUE WITH RISING TEMPS PROBABLE FOR FIRST TWO FORECAST PERIODS. ETA LOW LEVEL THERMAL PATTERN WITH STRONG/PERSISTENT WAA THROUGH DAYBREAK TUESDAY WITH 925MB TEMPS RISING FROM 2-4C TO LOWER TEENS BY 12Z TUE. FIRST AREA OF RAIN/BEST LIFT LIFTING NORTHEAST THROUGH THIS MORNING MAY HAVE TO HANG ONTO SOME HIGHER POPS NORTHEAST THIS AM...THEN WILL CONTINUE WITH CURRENT DRY FORECAST FOR LATE MORNING INTO EVENING AHEAD OF NEXT SYSTEM...COULD BE SOME SPOTTY TRACE DZ THOUGH WITH STRATUS LATE MORNING AND THEN CIGS LOWERING AGAIN AFTER DARK...HOWEVER BUFKIT XSECTIONS SHOWING UVM IN MOIST LAYER LACKING. INCREASING POPS TO CATEGORICAL BEYOND 06Z TONIGHT. PWAT INCREASES TO 1.25 INCHES WITH LONG HOOKED HODOGRAPH WITH 0-6KM BULK SHEAR VECTORS GREATER THAN 50KTS...DEEP UVM AND SHOWALTER NEAR 0C/H7-H5 LAPSE RATES NEAR 6.5 C/KM WILL MENTION AT LEAST THE POTENTIAL FOR TSRA LATE TONIGHT SOUTH AND EAST. LONG TERM TUESDAY THROUGH SUNDAY FIRST CONCERN WILL BE THE PROGRESSIVE CUTOFF LOW NOW DIGGING INTO THE SOUTHWEST US. THIS SYSTEM WILL REMAIN PROGRESSIVE AND EJECT OUT INTO THE SOUTHERN PLAINS TODAY AND SPAWN LEE SIDE SURFACE CYCLOGENESIS. SYSTEM WILL SWING NORTHEAST INTO THE LOWER GREAT LAKES BY 12Z TUES. ETA AND GFS HAVE RATHER SIGNIFICANT DIFFERENCES IN THE TRACK OF THE SURFACE LOW WITH THE ETA FURTHER WEST AND DEEPER WHILE THE GFS IS WEAKER AND FURTHER EAST. ETA HAS BEEN SUPERIOR THE PAST SEVERAL WEEKS WITH THESE SOUTHERN STREAM SYSTEMS. EACH ONE HAS COME OUT FURTHER NORTHWEST AND MORE WOUND UP THAN MODELS SUGGEST IN THE 36 TO 48 HOUR TIME FRAME. GFS ALSO APPEARS TO BE SUFFERING FROM CONVECTIVE FEEDBACK BY 12Z THURS WITH ERRONEOUS CONVECTIVELY INDUCED DYNAMICS DRAWING THE SURFACE LOW TOO FAR EAST. WILL GO WITH THE FURTHER WEST AND STRONGER ETA SOLUTION. WITH THE ETA IDEA...MAIN PUSH OF PRECIP WILL BE EXITING THE NORTH AND EAST AROUND 12Z TUE WITH VERY STRONG MID LEVEL JET BUILDING DRY SLOT IN BY MIDDAY. WILL FOLLOW LOWER ETA POPS WITH LIKELY NORTH AND CHANCE SOUTH...MAINLY FOR THE MORNING. AFTERNOON COULD END UP BEING MAINLY DRY. 925MB TEMPS SOAR TO +14C AT 12Z TUE EAST AND +10 NORTHWEST. EVEN MIXED DOWN MOIST ADIABATICALLY THIS SUPPORTS MID 50S NORTHWEST TO LOW 60S SOUTHEAST. WILL NOT BE QUITE THAT AGGRESSIVE YET...BUT PLAY AS UPPER 50S SOUTHEAST TO LOW 50S NORTHWEST. THESE WILL BE MORNING HIGHS WITH STRONG CAA DROPPING TEMPS BY AFTERNOON. ANOTHER CONCERN WILL BE WINDS ON THURSDAY. IF ETA SOLUTION VERIFIES SURFACE LOW WILL BE IN THE PROCESS OF RAPIDLY DEEPENING AS IT MOVES BY JUST NORTHWEST OF THE CWA TUE MORNING. ETA BUFKIT SHOWING VERY NICE ISSALOBARIC FALL/RISE COUPLET OF -8MB/3HR TO +6MB/3HR THURSDAY MORNING. STRONG CAA AND PRESSURE RISES DURING THE AFTERNOON WILL BE ABLE TO MIX DOWN HIGHER WIND SPEEDS FROM ALOFT WITH ETA BUFKIT MOMENTUM TRANSFER SCHEMES SHOWING 40-45KT GUST POTENTIAL. WILL RAMP WINDS UP IN GRIDS. IF ETA SOLUTION VERIFIES WINDS COULD APPROACH ADVISORY CRITERIA. COLDER AIR WRAPS IN FOR TUESDAY NIGHT. WILL RETAIN A LOW CHANCE FOR SW OVER THE NORTH WITH WRAP AROUND MOISTURE REMAINING NEARBY. 850MB TEMPS -3C TO -5C RANGE NOT COLD ENOUGH FOR ANY SIGNIFICANT LAKE EFFECT. SURFACE HIGH BUILDS IN FOR WED BRINING FAIR SKIES AND WAA ALREADY BEGINNING WITH MODERATING TEMPS. NEXT BIG TICKET ITEM WILL ARRIVE BY THE END OF THE WEEK. ALL MEDIUM RANGE GUIDANCE IN GENERAL AGREEMENT IN DIGGING A FULL LATITUDE TROUGH INTO THE EASTERN CONUS BY LATE WEEK. THIS CAN BE TRACED BACK TO THE RECURVING OF TYPHOON NANMADOL OVER THE WESTERN PACIFIC A FEW DAYS AGO. THIS RECURVING VERY OFTEN SIGNALS A DIGGING TROUGH INTO THE EASTERN CONUS ABOUT A WEEK LATER AS THE STRONG INFLUX OF ENERGY INTO NORTHERN LATITUDES CAUSES DOWNSTREAM AMPLIFICATION. GFS ENSEMBLES SHOWING THE PNA INDEX TRENDING STRONGLY POSITIVE BY LATE WEEK BUT ALSO SHOW THE NAO AND AO INDEX REMAINING POSITIVE OVER THE NEXT 10 DAYS. THIS WOULD SUPPORT THE TROUGH DIGGING INTO THE EASTERN US LATE WEEK. BUT WITH THE NAO AND AO REMAINING POSITIVE HIGH LATITUDE BLOCKING WILL NOT SET UP AND ALLOW FOR A PROLONGED EAST COAST TROUGH. GFS ENSEMBLES ALSO SHOWING THE POLAR VORTEX REMAINS DISPLACED VERY FAR NORTH THIS TIME OF YEAR...OVER THE CANADIAN ARCHIPELEGO NORTH OF THE ARCTIC CIRCLE INSTEAD OF OVER HUDSON BAY. WITH THIS IN MIND...TROUGH FOR LATE WEEK WILL LIKELY BE PROGRESSIVE IN NATURE AND NOT REPRESENT A MAJOR PATTERN SHIFT. WITH THAT BEING SAID...THERE WILL BE A TURN TOWARDS SIGNIFICANTLY COOLER TEMPS ALONG WITH THE CHANCES OF INITIALLY RAIN THEN SNOW LATE WEEK AS TROUGH DIGS IN. MODELS SHOWING MUCH MORE SPREAD IN SURFACE SOLUTIONS...WHICH IS TO BE EXPECTED. FOR NOW WILL RETAIN CONTINUITY AND GO WITH CHANCE POPS THURS PM THROUGH FRI NGT. A CLIPPER WILL DROP SOUTHEAST IN THE MEAN FLOW SUNDAY WITH ANOTHER CHANCE OF PRECIP. CURRENT GFS TRACKS THIS SYSTEM JUST NORTH OF THE CWA...BUT TRACK OF SURFACE LOW WILL BE CONTINGENT ON THE STRENGTH AND ORIENTATION OF THE MEAN TROUGH THAT DEVELOPS BEFOREHAND. WILL AGAIN STICK WITH CONTINUITY HERE FOR A CHANCE OF RA/SN. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. && $$ AVIATION...SMITH SHORT TERM...MURPHY/SMITH LONG TERM...HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 800 AM EST MON DEC 6 2004 .UPDATE... UPDATE EARLY THIS MORNING TO REMOVE RAIN FROM NORTHEAST CWA AND INCLUDE DRIZZLE AND FOG ACROSS CWA INTO MID MORNING THEN CLOUDY THROUGH AFTERNOON. ALSO BUMPED UP MAX TEMPS A COUPLE DEGREES BASED ON CURRENT READINGS AND TEMPS UPSTREAM. && .AVIATION... MAIN CONCERNS FOR THE 12Z TAF CYCLE REVOLVE AROUND EXPANSIVE AREA OF IFR CIGS NOW MOVING INTO THE TERMINALS. LATEST SATELLITE AND CIG DATA SHOW LARGE AREA OF IFR AND LIFR COVERING MOST OF INDIANA AND EXTENDING BACK INTO ILLINOIS AND IOWA. VSBY NOT MUCH BETTER WITH MOST LOCATIONS IFR. MODEL CROSS SECTIONS SHOWING LOW LEVELS REMAINING NEARLY SATURATED TODAY. ETA BUFKIT DOES OFFER SOME HOPE FOR A SLOW RISE OF CIGS AND VSBY IMPROVEMENT THIS AFTERNOON WITH LCL HEIGHTS SLOWLY CLIMBING OUT TO ABOUT 1500FT. WILL KEEP THINGS IFR AT BOTH SITES THROUGH 19Z...THEN OFFER SLOW IMPROVEMENT TO MVFR CIGS THIS AFTERNOON. NEXT ROUND OF RAIN MOVES IN TONIGHT...MAINLY AFTER MIDNIGHT. ETA MODEL SHOWING A SURGE OF ISENTROPIC LIFT AND MOISTURE ADVECTION ON 290K AND 295K SURFACES BY 06Z. THIS COMBINED WITH DPVA FROM STRONG SOUTHERN STREAM SHORTWAVE AND FAVORABLE JET DYNAMICS WILL PRODUCE A PERIOD OF DEEP UVV. BOTH MET/MAV SUGGEST CIGS WILL BEGIN TO TANK AGAIN LATE TONIGHT AS COLUMN BECOMES FULLY SATURATED ONCE AGAIN. && .PREVIOUS DISCUSSION... TODAY AND TONIGHT ISSUES AGAIN WITH MODEL PREFERENCE. OPERATIONAL GFS 24 HOURS AGO HAD TRENDED IN RIGHT DIRECTION BUT NOW TOO FAR SOUTHEAST WITH SURFACE LOW AT 12Z TUESDAY. ETA WAS THE OUTLIER 24 HOURS AGO AND NOW APPEARS TO HAVE BETTER HANDLE ON ENERGY TO LIFT OUT OF SOUTHERN AZ. ETA HARD TO BEAT WITH NGM/20KM DEV RUC AGREEMENT AND EVEN SEVERAL GFS ENSEMBLE MEMBERS LEANING FURTHER NORTHWEST AS WELL. ECMWF/UKMET IN BETWEEN BUT AT LEAST TRACKING SURFACE LOW THROUGH FORECAST AREA. FIRST ISSUE WITH RISING TEMPS PROBABLE FOR FIRST TWO FORECAST PERIODS. ETA LOW LEVEL THERMAL PATTERN WITH STRONG/PERSISTENT WAA THROUGH DAYBREAK TUESDAY WITH 925MB TEMPS RISING FROM 2-4C TO LOWER TEENS BY 12Z TUE. FIRST AREA OF RAIN/BEST LIFT LIFTING NORTHEAST THROUGH THIS MORNING MAY HAVE TO HANG ONTO SOME HIGHER POPS NORTHEAST THIS AM...THEN WILL CONTINUE WITH CURRENT DRY FORECAST FOR LATE MORNING INTO EVENING AHEAD OF NEXT SYSTEM...COULD BE SOME SPOTTY TRACE DZ THOUGH WITH STRATUS LATE MORNING AND THEN CIGS LOWERING AGAIN AFTER DARK...HOWEVER BUFKIT XSECTIONS SHOWING UVM IN MOIST LAYER LACKING. INCREASING POPS TO CATEGORICAL BEYOND 06Z TONIGHT. PWAT INCREASES TO 1.25 INCHES WITH LONG HOOKED HODOGRAPH WITH 0-6KM BULK SHEAR VECTORS GREATER THAN 50KTS...DEEP UVM AND SHOWALTER NEAR 0C/H7-H5 LAPSE RATES NEAR 6.5 C/KM WILL MENTION AT LEAST THE POTENTIAL FOR TSRA LATE TONIGHT SOUTH AND EAST. LONG TERM TUESDAY THROUGH SUNDAY FIRST CONCERN WILL BE THE PROGRESSIVE CUTOFF LOW NOW DIGGING INTO THE SOUTHWEST US. THIS SYSTEM WILL REMAIN PROGRESSIVE AND EJECT OUT INTO THE SOUTHERN PLAINS TODAY AND SPAWN LEE SIDE SURFACE CYCLOGENESIS. SYSTEM WILL SWING NORTHEAST INTO THE LOWER GREAT LAKES BY 12Z TUES. ETA AND GFS HAVE RATHER SIGNIFICANT DIFFERENCES IN THE TRACK OF THE SURFACE LOW WITH THE ETA FURTHER WEST AND DEEPER WHILE THE GFS IS WEAKER AND FURTHER EAST. ETA HAS BEEN SUPERIOR THE PAST SEVERAL WEEKS WITH THESE SOUTHERN STREAM SYSTEMS. EACH ONE HAS COME OUT FURTHER NORTHWEST AND MORE WOUND UP THAN MODELS SUGGEST IN THE 36 TO 48 HOUR TIME FRAME. GFS ALSO APPEARS TO BE SUFFERING FROM CONVECTIVE FEEDBACK BY 12Z THURS WITH ERRONEOUS CONVECTIVELY INDUCED DYNAMICS DRAWING THE SURFACE LOW TOO FAR EAST. WILL GO WITH THE FURTHER WEST AND STRONGER ETA SOLUTION. WITH THE ETA IDEA...MAIN PUSH OF PRECIP WILL BE EXITING THE NORTH AND EAST AROUND 12Z TUE WITH VERY STRONG MID LEVEL JET BUILDING DRY SLOT IN BY MIDDAY. WILL FOLLOW LOWER ETA POPS WITH LIKELY NORTH AND CHANCE SOUTH...MAINLY FOR THE MORNING. AFTERNOON COULD END UP BEING MAINLY DRY. 925MB TEMPS SOAR TO +14C AT 12Z TUE EAST AND +10 NORTHWEST. EVEN MIXED DOWN MOIST ADIABATICALLY THIS SUPPORTS MID 50S NORTHWEST TO LOW 60S SOUTHEAST. WILL NOT BE QUITE THAT AGGRESSIVE YET...BUT PLAY AS UPPER 50S SOUTHEAST TO LOW 50S NORTHWEST. THESE WILL BE MORNING HIGHS WITH STRONG CAA DROPPING TEMPS BY AFTERNOON. ANOTHER CONCERN WILL BE WINDS ON THURSDAY. IF ETA SOLUTION VERIFIES SURFACE LOW WILL BE IN THE PROCESS OF RAPIDLY DEEPENING AS IT MOVES BY JUST NORTHWEST OF THE CWA TUE MORNING. ETA BUFKIT SHOWING VERY NICE ISSALOBARIC FALL/RISE COUPLET OF -8MB/3HR TO +6MB/3HR THURSDAY MORNING. STRONG CAA AND PRESSURE RISES DURING THE AFTERNOON WILL BE ABLE TO MIX DOWN HIGHER WIND SPEEDS FROM ALOFT WITH ETA BUFKIT MOMENTUM TRANSFER SCHEMES SHOWING 40-45KT GUST POTENTIAL. WILL RAMP WINDS UP IN GRIDS. IF ETA SOLUTION VERIFIES WINDS COULD APPROACH ADVISORY CRITERIA. COLDER AIR WRAPS IN FOR TUESDAY NIGHT. WILL RETAIN A LOW CHANCE FOR SW OVER THE NORTH WITH WRAP AROUND MOISTURE REMAINING NEARBY. 850MB TEMPS -3C TO -5C RANGE NOT COLD ENOUGH FOR ANY SIGNIFICANT LAKE EFFECT. SURFACE HIGH BUILDS IN FOR WED BRINING FAIR SKIES AND WAA ALREADY BEGINNING WITH MODERATING TEMPS. NEXT BIG TICKET ITEM WILL ARRIVE BY THE END OF THE WEEK. ALL MEDIUM RANGE GUIDANCE IN GENERAL AGREEMENT IN DIGGING A FULL LATITUDE TROUGH INTO THE EASTERN CONUS BY LATE WEEK. THIS CAN BE TRACED BACK TO THE RECURVING OF TYPHOON NANMADOL OVER THE WESTERN PACIFIC A FEW DAYS AGO. THIS RECURVING VERY OFTEN SIGNALS A DIGGING TROUGH INTO THE EASTERN CONUS ABOUT A WEEK LATER AS THE STRONG INFLUX OF ENERGY INTO NORTHERN LATITUDES CAUSES DOWNSTREAM AMPLIFICATION. GFS ENSEMBLES SHOWING THE PNA INDEX TRENDING STRONGLY POSITIVE BY LATE WEEK BUT ALSO SHOW THE NAO AND AO INDEX REMAINING POSITIVE OVER THE NEXT 10 DAYS. THIS WOULD SUPPORT THE TROUGH DIGGING INTO THE EASTERN US LATE WEEK. BUT WITH THE NAO AND AO REMAINING POSITIVE HIGH LATITUDE BLOCKING WILL NOT SET UP AND ALLOW FOR A PROLONGED EAST COAST TROUGH. GFS ENSEMBLES ALSO SHOWING THE POLAR VORTEX REMAINS DISPLACED VERY FAR NORTH THIS TIME OF YEAR...OVER THE CANADIAN ARCHIPELEGO NORTH OF THE ARCTIC CIRCLE INSTEAD OF OVER HUDSON BAY. WITH THIS IN MIND...TROUGH FOR LATE WEEK WILL LIKELY BE PROGRESSIVE IN NATURE AND NOT REPRESENT A MAJOR PATTERN SHIFT. WITH THAT BEING SAID...THERE WILL BE A TURN TOWARDS SIGNIFICANTLY COOLER TEMPS ALONG WITH THE CHANCES OF INITIALLY RAIN THEN SNOW LATE WEEK AS TROUGH DIGS IN. MODELS SHOWING MUCH MORE SPREAD IN SURFACE SOLUTIONS...WHICH IS TO BE EXPECTED. FOR NOW WILL RETAIN CONTINUITY AND GO WITH CHANCE POPS THURS PM THROUGH FRI NGT. A CLIPPER WILL DROP SOUTHEAST IN THE MEAN FLOW SUNDAY WITH ANOTHER CHANCE OF PRECIP. CURRENT GFS TRACKS THIS SYSTEM JUST NORTH OF THE CWA...BUT TRACK OF SURFACE LOW WILL BE CONTINGENT ON THE STRENGTH AND ORIENTATION OF THE MEAN TROUGH THAT DEVELOPS BEFOREHAND. WILL AGAIN STICK WITH CONTINUITY HERE FOR A CHANCE OF RA/SN. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. && $$ AVIATION...SMITH SHORT TERM...MURPHY/SMITH LONG TERM...HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 641 AM EST MON DEC 6 2004 .AVIATION... MAIN CONCERNS FOR THE 12Z TAF CYCLE REVOLVE AROUND EXPANSIVE AREA OF IFR CIGS NOW MOVING INTO THE TERMINALS. LATEST SATELLITE AND CIG DATA SHOW LARGE AREA OF IFR AND LIFR COVERING MOST OF INDIANA AND EXTENDING BACK INTO ILLINOIS AND IOWA. VSBY NOT MUCH BETTER WITH MOST LOCATIONS IFR. MODEL CROSS SECTIONS SHOWING LOW LEVELS REMAINING NEARLY SATURATED TODAY. ETA BUFKIT DOES OFFER SOME HOPE FOR A SLOW RISE OF CIGS AND VSBY IMPROVEMENT THIS AFTERNOON WITH LCL HEIGHTS SLOWLY CLIMBING OUT TO ABOUT 1500FT. WILL KEEP THINGS IFR AT BOTH SITES THROUGH 19Z...THEN OFFER SLOW IMPROVEMENT TO MVFR CIGS THIS AFTERNOON. NEXT ROUND OF RAIN MOVES IN TONIGHT...MAINLY AFTER MIDNIGHT. ETA MODEL SHOWING A SURGE OF ISENTROPIC LIFT AND MOISTURE ADVECTION ON 290K AND 295K SURFACES BY 06Z. THIS COMBINED WITH DPVA FROM STRONG SOUTHERN STREAM SHORTWAVE AND FAVORABLE JET DYNAMICS WILL PRODUCE A PERIOD OF DEEP UVV. BOTH MET/MAV SUGGEST CIGS WILL BEGIN TO TANK AGAIN LATE TONIGHT AS COLUMN BECOMES FULLY SATURATED ONCE AGAIN. && .SHORT TERM... TODAY AND TONIGHT ISSUES AGAIN WITH MODEL PREFERENCE. OPERATIONAL GFS 24 HOURS AGO HAD TRENDED IN RIGHT DIRECTION BUT NOW TOO FAR SOUTHEAST WITH SURFACE LOW AT 12Z TUESDAY. ETA WAS THE OUTLIER 24 HOURS AGO AND NOW APPEARS TO HAVE BETTER HANDLE ON ENERGY TO LIFT OUT OF SOUTHERN AZ. ETA HARD TO BEAT WITH NGM/20KM DEV RUC AGREEMENT AND EVEN SEVERAL GFS ENSEMBLE MEMBERS LEANING FURTHER NORTHWEST AS WELL. ECMWF/UKMET IN BETWEEN BUT AT LEAST TRACKING SURFACE LOW THROUGH FORECAST AREA. FIRST ISSUE WITH RISING TEMPS PROBABLE FOR FIRST TWO FORECAST PERIODS. ETA LOW LEVEL THERMAL PATTERN WITH STRONG/PERSISTENT WAA THROUGH DAYBREAK TUESDAY WITH 925MB TEMPS RISING FROM 2-4C TO LOWER TEENS BY 12Z TUE. FIRST AREA OF RAIN/BEST LIFT LIFTING NORTHEAST THROUGH THIS MORNING MAY HAVE TO HANG ONTO SOME HIGHER POPS NORTHEAST THIS AM...THEN WILL CONTINUE WITH CURRENT DRY FORECAST FOR LATE MORNING INTO EVENING AHEAD OF NEXT SYSTEM...COULD BE SOME SPOTTY TRACE DZ THOUGH WITH STRATUS LATE MORNING AND THEN CIGS LOWERING AGAIN AFTER DARK...HOWEVER BUFKIT XSECTIONS SHOWING UVM IN MOIST LAYER LACKING. INCREASING POPS TO CATEGORICAL BEYOND 06Z TONIGHT. PWAT INCREASES TO 1.25 INCHES WITH LONG HOOKED HODOGRAPH WITH 0-6KM BULK SHEAR VECTORS GREATER THAN 50KTS...DEEP UVM AND SHOWALTER NEAR 0C/H7-H5 LAPSE RATES NEAR 6.5 C/KM WILL MENTION AT LEAST THE POTENTIAL FOR TSRA LATE TONIGHT SOUTH AND EAST. && .LONG TERM... TUESDAY THROUGH SUNDAY FIRST CONCERN WILL BE THE PROGRESSIVE CUTOFF LOW NOW DIGGING INTO THE SOUTHWEST US. THIS SYSTEM WILL REMAIN PROGRESSIVE AND EJECT OUT INTO THE SOUTHERN PLAINS TODAY AND SPAWN LEE SIDE SURFACE CYCLOGENESIS. SYSTEM WILL SWING NORTHEAST INTO THE LOWER GREAT LAKES BY 12Z TUES. ETA AND GFS HAVE RATHER SIGNIFICANT DIFFERENCES IN THE TRACK OF THE SURFACE LOW WITH THE ETA FURTHER WEST AND DEEPER WHILE THE GFS IS WEAKER AND FURTHER EAST. ETA HAS BEEN SUPERIOR THE PAST SEVERAL WEEKS WITH THESE SOUTHERN STREAM SYSTEMS. EACH ONE HAS COME OUT FURTHER NORTHWEST AND MORE WOUND UP THAN MODELS SUGGEST IN THE 36 TO 48 HOUR TIME FRAME. GFS ALSO APPEARS TO BE SUFFERING FROM CONVECTIVE FEEDBACK BY 12Z THURS WITH ERRONEOUS CONVECTIVELY INDUCED DYNAMICS DRAWING THE SURFACE LOW TOO FAR EAST. WILL GO WITH THE FURTHER WEST AND STRONGER ETA SOLUTION. WITH THE ETA IDEA...MAIN PUSH OF PRECIP WILL BE EXITING THE NORTH AND EAST AROUND 12Z TUE WITH VERY STRONG MID LEVEL JET BUILDING DRY SLOT IN BY MIDDAY. WILL FOLLOW LOWER ETA POPS WITH LIKELY NORTH AND CHANCE SOUTH...MAINLY FOR THE MORNING. AFTERNOON COULD END UP BEING MAINLY DRY. 925MB TEMPS SOAR TO +14C AT 12Z TUE EAST AND +10 NORTHWEST. EVEN MIXED DOWN MOIST ADIABATICALLY THIS SUPPORTS MID 50S NORTHWEST TO LOW 60S SOUTHEAST. WILL NOT BE QUITE THAT AGGRESSIVE YET...BUT PLAY AS UPPER 50S SOUTHEAST TO LOW 50S NORTHWEST. THESE WILL BE MORNING HIGHS WITH STRONG CAA DROPPING TEMPS BY AFTERNOON. ANOTHER CONCERN WILL BE WINDS ON THURSDAY. IF ETA SOLUTION VERIFIES SURFACE LOW WILL BE IN THE PROCESS OF RAPIDLY DEEPENING AS IT MOVES BY JUST NORTHWEST OF THE CWA TUE MORNING. ETA BUFKIT SHOWING VERY NICE ISSALOBARIC FALL/RISE COUPLET OF -8MB/3HR TO +6MB/3HR THURSDAY MORNING. STRONG CAA AND PRESSURE RISES DURING THE AFTERNOON WILL BE ABLE TO MIX DOWN HIGHER WIND SPEEDS FROM ALOFT WITH ETA BUFKIT MOMENTUM TRANSFER SCHEMES SHOWING 40-45KT GUST POTENTIAL. WILL RAMP WINDS UP IN GRIDS. IF ETA SOLUTION VERIFIES WINDS COULD APPROACH ADVISORY CRITERIA. COLDER AIR WRAPS IN FOR TUESDAY NIGHT. WILL RETAIN A LOW CHANCE FOR SW OVER THE NORTH WITH WRAP AROUND MOISTURE REMAINING NEARBY. 850MB TEMPS -3C TO -5C RANGE NOT COLD ENOUGH FOR ANY SIGNIFICANT LAKE EFFECT. SURFACE HIGH BUILDS IN FOR WED BRINING FAIR SKIES AND WAA ALREADY BEGINNING WITH MODERATING TEMPS. NEXT BIG TICKET ITEM WILL ARRIVE BY THE END OF THE WEEK. ALL MEDIUM RANGE GUIDANCE IN GENERAL AGREEMENT IN DIGGING A FULL LATITUDE TROUGH INTO THE EASTERN CONUS BY LATE WEEK. THIS CAN BE TRACED BACK TO THE RECURVING OF TYPHOON NANMADOL OVER THE WESTERN PACIFIC A FEW DAYS AGO. THIS RECURVING VERY OFTEN SIGNALS A DIGGING TROUGH INTO THE EASTERN CONUS ABOUT A WEEK LATER AS THE STRONG INFLUX OF ENERGY INTO NORTHERN LATITUDES CAUSES DOWNSTREAM AMPLIFICATION. GFS ENSEMBLES SHOWING THE PNA INDEX TRENDING STRONGLY POSITIVE BY LATE WEEK BUT ALSO SHOW THE NAO AND AO INDEX REMAINING POSITIVE OVER THE NEXT 10 DAYS. THIS WOULD SUPPORT THE TROUGH DIGGING INTO THE EASTERN US LATE WEEK. BUT WITH THE NAO AND AO REMAINING POSITIVE HIGH LATITUDE BLOCKING WILL NOT SET UP AND ALLOW FOR A PROLONGED EAST COAST TROUGH. GFS ENSEMBLES ALSO SHOWING THE POLAR VORTEX REMAINS DISPLACED VERY FAR NORTH THIS TIME OF YEAR...OVER THE CANADIAN ARCHIPELEGO NORTH OF THE ARCTIC CIRCLE INSTEAD OF OVER HUDSON BAY. WITH THIS IN MIND...TROUGH FOR LATE WEEK WILL LIKELY BE PROGRESSIVE IN NATURE AND NOT REPRESENT A MAJOR PATTERN SHIFT. WITH THAT BEING SAID...THERE WILL BE A TURN TOWARDS SIGNIFICANTLY COOLER TEMPS ALONG WITH THE CHANCES OF INITIALLY RAIN THEN SNOW LATE WEEK AS TROUGH DIGS IN. MODELS SHOWING MUCH MORE SPREAD IN SURFACE SOLUTIONS...WHICH IS TO BE EXPECTED. FOR NOW WILL RETAIN CONTINUITY AND GO WITH CHANCE POPS THURS PM THROUGH FRI NGT. A CLIPPER WILL DROP SOUTHEAST IN THE MEAN FLOW SUNDAY WITH ANOTHER CHANCE OF PRECIP. CURRENT GFS TRACKS THIS SYSTEM JUST NORTH OF THE CWA...BUT TRACK OF SURFACE LOW WILL BE CONTINGENT ON THE STRENGTH AND ORIENTATION OF THE MEAN TROUGH THAT DEVELOPS BEFOREHAND. WILL AGAIN STICK WITH CONTINUITY HERE FOR A CHANCE OF RA/SN. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. && $$ AVIATION...HITCHCOCK SHORT TERM...MURPHY LONG TERM...HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 324 PM CST MON DEC 6 2004 .DISCUSSION... SURFACE LOW PRESSURE CURRENTLY TAKING SHAPE OVER THE TEXAS PANHANDLE WILL CONTINUE TO DEEPEN TONIGHT AND LIFT QUICKLY NORTHEAST AS A STRONG SHORTWAVE HAS QUICKLY COME ON SHORE TODAY AND RACED EAST INTO SE NEW MEXICO. ACROSS THE STATE...LOW CLOUDS AND FOG HAVE HELD ON ALL DAY ACROSS THE STATE WITH THE LOWEST CONDITIONS NORTH OF A WARM FRONT WHICH CURRENTLY EXTENDED ACROSS NORTHEAST IOWA. VISIBILITIES HAVE BEEN NEAR ZERO NORTH OF THE FRONT WITH HIGHER VISIBILITIES TO THE SOUTH. EXPECT VISIBILITIES TO DROP TO BELOW ONE QUARTER OF A MILE NEAR THE WARM FRONT OVERNIGHT AND WILL ISSUE A DENSE FOG ADVISORY FOR THE NORTHEAST THIRD. DIFFERENCES REMAIN AMONG THE GFS/ETA/RUC ON HOW MUCH THE SOUTHERN PLAINS LOW WILL DEEPEN AS IT LIFTS NORTHEAST OVERNIGHT INTO THE LOWER OHIO RIVER VALLEY BY TUESDAY MORNING. THERE WILL BE AN ABUNDANCE OF WARM AIR WITH THE SYSTEM...KEEPING ANY PRECIPITATION IN THE FORM OF LIQUID. SOME LIGHT RAIN MAY LINGER ACROSS THE SOUTHEAST THROUGH 15Z BEFORE MOVING EAST. MAIN CONCERN ON TUESDAY WILL BE CLOUD COVER. OVERALL THE NORTHEAST HALF OF THE FORECAST AREA WILL LIKELY REMAIN CLOUD ALL DAY WITH A FEW BREAKS ACROSS THE SOUTH AND WEST. THERE IS A BIG DISCREPANCY AMONG GUIDANCE HIGHS AND HAVE LEANED TOWARD THE COOLER MET WITH EXPECTED CLOUD COVER. GUIDANCE APPEARS TOO WARM AGAIN ON WEDNESDAY. A BKN/OVC MID TO HIGH LEVEL CLOUD DECK IS EXPECTED IN ADVANCE OF NORTHWEST FLOW SHORT WAVE THAT IS DUE TO ARRIVE LATE WEDNESDAY. DESPITE GOOD SOUTHERLY SFC FLOW...CLOUDS SHOULD PREVENT A 20 DEGREE DIURNAL RANGE FROM MORNING LOWS AS GUIDANCE WOULD SUGGEST. .LONG TERM(THU-MON)... PERIOD WILL BE DOMINATED BY SEVERAL SHORTWAVES RACING THROUGH THE NORTHWEST FLOW. BEST CHANCE FOR PRECIPITATION DURING THE PERIOD WILL BE ACROSS THE EAST ON THURSDAY AS A DISTURBANCE MOVES DOWN THE MISSOURI RIVER VALLEY. THE REMAINDER OF THE SYSTEMS WILL BE ALBERTA CLIPPERS TO THE NORTH AND THESE SYSTEMS HAVE A DIFFICULT TIME PRODUCING PRECIPITATION SOUTH OF THE SFC LOW. HAVE REDUCED POPS TO 20 OR BELOW FOR FRI-MON. TEMPERATURES THU-SAT WILL BE ABOVE SEASONAL VALUES. A STRONG COLD FRONT IS ANTICIPATED TO MOVE ACROSS THE STATE DURING THE DAY ON SUNDAY. AT THIS TIME THE SYSTEM HAS THE POTENTIAL TO BE QUITE WINDY. DESPITE THE COLD FRONT...NO ARCTIC AIR IS IN SIGHT. && .DMX WATCHES/WARNINGS/ADVISORIES...DENSE FOG ADVISORY FROM 9PM-6AM TONIGHT FOR NORTH CENTRAL IOWA. IAZ004>007-015>017-024>028-036>039-070430- && $$ DONAVON ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 410 PM EST MON DEC 06 2004 .DISCUSSION... MAIN FCST CONCERNS ARE PCPN TYPE/TRENDS TONIGHT THROUGH TUE. WV IMAGERY AND RUC ANALYSIS INDICATED PATTERN WITH TROFFING OVER THE W AND SE CONUS RDG LEAVING SW FLOW INTO THE GRT LAKES. LEAD SHRTWV EXTENDED ACRS THE THE UP WITH DEEPER MOISTURE TO THE NORTH. ANOTHER WEAK SHRTWV WAS LOCATED OVER S CNTRL NEB WHILE THE MAIN VIGOROUS SRN STREAM UPSTREAM VORT WAS LOCATED OVER SE NM. AT THE SFC...ESE FLOW PREVAILED BTWN NRN ONTARIO /QUEBEC RDG AND DISORGANIZED TROF OVER THE PLAINS. RADARS INDICATED MAIN BAND OF -SN HAD LIFTED N OF UPR MI WITH MAINLY LOWER LVL RETURNS SPREADING THROUGH CNTRL UPR MI. UPSTREAM (KMPX/KARX/KMKX) VAD WND PRFLS ALSO SHOWED LACK OF RETURNS ABV 6K FT. WHILE LITTLE -FZDZ NOTED UPSTREAM...OCNL MIX WITH -FZDZSN WAS OBSERVED AT THE NWS OFFICE. TONIGHT...WITH DEPARTURE OF DECENT SHRTWV DYNAMICS...LOWER LVL (280K-290K) ISENTROPIC LIFT SHOULD SUSTAIN AREA OF VERY LGT PCPN. SINCE MDL SNDGS SHOW PROMINENT ENOUGH 800-600 MB DRYING TO DISRUPT SUPPLY OF ICE NUCLEI...WILL EMPHASIZE -FZDZ/-DZ AS TEMPS WERE STRADDLING THE FREEZING MARK..ABV OVER THE S AND NEAR THE LAKES BUT BLO INLAND...AND ARE EXPECTED TO REMAIN NEARLY STEADY OR ONLY SLOWLY RISING. WEAK UPSTREAM SHRTWV AND MDLS DEPICTION OF SHRINKING DRY LYR LATE TONIGHT ALSO WILL ALSO KEEP POTENTIAL FOR -SN GOING. HOWEVER...WITH GENERALLY WEAK LIFT...LITTLE OR NO SNOW ACCUMULATION IS EXPECTED. TUE...MDL DIFFERENCES REMAIN WITH THE HANDLING OF THE SRN STREAM VORT AND DEVELOPMENT/PLACEMENT OF THE ASSOCIATED LOW AND THERMAL FIELDS. THE 12Z/18Z CONTINUE TO FCST A MORE NRLY TRACK THAN THE GFS. GIVEN THE STRENGTH OF THE UPSTREAM SHRTWV...A BLEND MORE TOWARD THE ETA IS PREFERRED. LIKE PREVIOUS RUNS...THE 12Z UKMET WOULD BE GOOD COMPROMISE. WITH VERY STRONG UPR LVL DIV FROM COUPLED JET PATTERN...DEEPENING LOW TO NEAR 986 MB OVER LK HURON BY 00Z/WED SEEMS REASONABLE. SO...EXPECT MAINLY LINGERING -FZDZSN DURING THE MORNING WITH PCPN SHIELD FROM THE STORM AFFECTING MAINLY THE SE 1/3 OF THE FORECAST AREA. DEVELOPING ENE FLOW AS THE LOW INTENSIFIES...INFLOW OVER VERY COLD AIR FROM NE ONTARIO MAY KEEP TEMP BLO FREEZING OVER INLAND PORTIONS OF E CNTRL UPR MI. ETA FCST SNDGS SUGGEST ENOUGH OF A WARM LYR FOR IP/FZRA POTENTIAL DURING THE AFTERNOON. WITH LINGERING UNCERTAINTY ON LOW STRENGTH/TRACK AND THERMAL PROFILE...NO HEADLINES ISSUED AT THIS TIME BUT WILL HIGHLIGHT IN HWO AND MENTION PCPN MIX IN THE GRIDS/ZFP. FARTHER WEST WHERE PCPN CHANCES ARE MORE MARGINAL...EXPECT MAINLY JUST SNOW OR RAIN WITH ANY WARM LYR CONFINED TO LOWER PORTION OF THE SNDG. TUE NIGHT...A TRAILING NRN STREAM SHRTWV ALONG WITH LINGERING LOW LVL MOISTURE AND CONV NEAR THE TROF AXIS MAY KEEP SOME -SN GOING OVER THE WEST. ALTHOUGH WINDS BECOME WNW..H8 TEMPS ONLY TO AROUND -5C WILL NOT PROVIDE ENOUGH INSTABILITY FOR LES. WED...EXPECT A DRY DAY BUT WITH CONSIDERABLE CLOUDS AS MID LVL AND SFC RDG WILL SLIDE EAST AS WAA DEVELOPS AHEAD OF THE NEXT SHRTWV AND SFC LOW MOVING IN FROM THE NRN PLAINS. WENT WITH ETA/GFS GUIDANCE BLEND FOR AS ONLY MODERATE WINDS MAY NOT BRING ENOUGH MIXING TO REACH WARMER GFS VALUES. WED NIGHT INTO THU...SHRTWV IN ZONAL PATTERN WITH WEAK TO MODERATE QG FORCING AND ASSOCIATED WAA WILL BE ENOUGH TO JUSTIFY AT LEAST CHANCE POPS FOR PCPN WED NIGHT. ETA/GFS 1000-850 THICKNESS SUGGESTS POSSIBILITY OF RA/SN MIX OVER THE SOUTH AND EAST. A BRIEF GAP IN PCPN CHANCES IS POSSIBLE BEFORE THE NEXT STRONGER SHRTWV NEAR BY LATER THU BUT WILL NOT ATTEMPT TO TIME A DRY PERIOD AT THIS POINT. FRI-MON...MDLS WERE IN BETTER THAN USUAL AGREEMENT...AT LEAST WITH RESPECT TO LARGE SCALE FEATURES. ACCORDINGLY...OPERATIONAL GFS LINED UP REASONABLY WELL WITH THE ENSEMBLE MEAN. SO...RELIED ON A BLEND OF THE 00Z/12Z GFS FOR DETAILS. 1000-850 THICKNESS PROG SUGGESTS CONTINUED POSSIBILITY OF RAIN OF RAIN SNOW MIX INTO FRI. WHILE H8 TEMPS BEHIND THE SYSTEM ARE NOT THAT COLD ONLY TO AROUND -10C...CYCLONIC FLOW WITH WRAP-AROUND MOISTURE SHOULD SUPPORT SOME LAKE ENHANCED -SHSN INTO AREAS FAVORED BY NRLY FLOW. EXPECT PAUSE IN PCPN AS WINDS BACK AHEAD OF THE NEXT CLIPPER. SOME UNCERTAINTY WITH AMOUNT OF WARMING AND RA/SN POTENTIAL...DEPENDING ON THE TRACK OF THE SHRTWV AND ASSOCIATED SFC LOW. FOR NOW...MDL CONSENSUS KEEPS ENOUGH COLD AIR IN PLACE FOR MAINLY SNOW. WITH TREND TOWARD MORE AMPLIFIED PNA PATTERN...INFLUX OF EVEN COLDER AIR WITH H8 TEMPS TO AROUND -15C WILL SUPPORT LES WITH POSSIBILITY OF SIGNIFICANT ACCUMULATIONS FOR LOCATIONS FAVORED BY N TO NW FLOW FROM SUN NIGHT INTO MON. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JLB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1030 AM EST MON DEC 06 2004 .DISCUSSION... MAIN FORECAST CONCERN IS PRECIPITATION TYPE AND NEED FOR ADVISORIES. CURRENT WEATHER...15Z WATER VAPOR LOOP SHOWED A SHRTWV MOVING INTO UPPER MICHIGAN WHILE RIDGING WAS COMING IN BEHIND IT OVER IOWA. MEANWHILE THE UPPER LEVEL SYSTEM WILL AFFECT THE U.P. TOMORROW WAS LOCATED OVER SOUTHWEST NEW MEXICO. SHRTWV MOVING INTO UPPER MICHIGAN HAS HELPED IN BRINGING A BAND OF SNOW. AMOUNTS SO FAR HAVE RANGE FROM 1 TO 2 INCHES...WITH THE MOST ALONG THE WISCONSIN BORDER COUNTIES. SEE WMO HEADER NOUS43 KMQT OR AWIPS PIL ARBPNSMQT FOR A LISTING OF SNOWFALL REPORTS. THIS BAND OF SNOW HAS ALSO BEEN SUPPORTED BY ISENTROPIC LIFT AS SEEN ON THE 285-295K SURFACES AND BY SOME WEAK FRONTOGENESIS IN THE 800-700MB LAYER. 12Z SOUNDINGS FROM GRB AND MSP ARE ALL REALLY MOIST...WITH NEAR SATURATION FROM THE SURFACE TO 400MB. ALL THREE SOUNDINGS WERE ALSO BELOW FREEZING...BUT THE MSP SOUNDING DOES DEPICT A NEAR ZERO LAYER AROUND 900MB. WITHOUT MUCH FORCING...THAT MOISTURE ON THE MSP SOUNDING COMBINED WITH NEAR ZERO LAYER HAS RESULTED IN FREEZING DRIZZLE THERE. FREEZING DRIZZLE HAS ALSO JUST STARTED IN RHINELANDER. AT THE SURFACE...BROAD LOW PRESSURE WAS LOCATED FROM KANSAS TO IOWA WITH A WARM FRONT EXTENDING EASTWARD ALONG I-80. BOTH THE RUC AND THE ETA INDICATE ISENTROPIC LIFT CONTINUING THIS AFTERNOON...WHICH WILL KEEP SOME PRECIPITATION GOING. HOWEVER...SUBSIDENCE AND DRYING COMING IN BEHIND THE PASSING SHRTWV WILL ALLOW PRECIPITATION TO DIMINISH IN INTENSITY FROM WHAT IT HAS BEEN THIS MORNING. MAIN QUESTION IS WHETHER THE SNOW WILL CHANGE OVER TO DRIZZLE OR PERHAPS FREEZING DRIZZLE. NEW 12Z ETA INDICATES THAT DRYING WILL TAKE PLACE ABOVE 750MB WHILE BELOW THAT THINGS STAY VERY MOIST. TEMPERATURES BELOW 750MB START OFF BETWEEN -8 AND -10C OVER THE U.P. AROUND NOON...BUT THEN WARM TO -4 TO -6C BY 00Z. SO DEFINITELY LOOKS LIKE A SNOW CHANGING TO A DRIZZLE SCENARIO. AS FOR TEMPERATURES DOWN NEAR THE SURFACE...CURRENTLY THEY ARE RUNNING IN THE MID 20S OVER MUCH OF THE U.P. AND NORTHERN WISCONSIN...EXCEPT ALONG LAKE MICHIGAN WHERE THEY ARE ABOVE FREEZING. ABOVE FREEZING TEMPERATURES WERE ALSO LOCATED ALONG AND SOUTH OF WISCONSIN HIGHWAY 29. DEWPOINTS ARE SIMILAR TO THE TEMPERATURES...SO DESPITE EASTERLY FLOW COMING FROM THE HIGH PRESSURE RIDGE TO THE EAST...DEWPOINTS REMAIN HIGH. LAMP GUIDANCE SUGGEST TEMPERATURES WARMING UP ABOVE FREEZING ALONG THE WISCONSIN BORDER BY LATE THIS AFTERNOON WHEREAS THE MET AND MAV GUIDANCE ARE A LITTLE MORE RELUCTANT...HOLDING OFF ABOVE FREEZING TEMPERATURES UNTIL MIDNIGHT. CURRENT FORECAST TIMING IN THE GRIDS LOOKS GOOD OF THE CHANGE OVER...AND WILL LEAVE IN THE MIX OF DRIZZLE OR FREEZING DRIZZLE. AS FOR AN ADVISORY...WITH THE LACK OF CONFIDENCE OF HAVING PURE FREEZING DRIZZLE FOR AN EXTENDED PERIOD OF TIME...WINDS EXPECTED TO VEER TO THE SOUTHEAST AND ROAD SURFACES BOTH WARM AND SALTED...NOT PLANNING ON GOING WITH ONE AT THE MOMENT. IF TEMPERATURES DO NOT RISE MUCH OVER THE NEXT FEW HOURS AND FREEZING DRIZZLE OCCURS AND PERSISTS...MAY UPDATE FORECAST LATER AND PUT OUT AN ADVISORY. COORDINATED WITH GRB AND APX...THANKS. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 545 AM EST MON DEC 06 2004 .DISCUSSION... FORECAST CONCERNS INCLUDE SNOW AMTS FOR TODAY THEN DZ/FZDZ THIS AFTERNOON INTO TONIGHT ALONG WITH MORE MIXED PRECIP TUESDAY. LATEST WATER VAPOR LOOP AND 5H RUC ANALYSIS SHOWS ONE SRN STREAM SHRTWV LIFTING NE INTO SRN WI AND SRN LWR MI WHILE ANOTHER STRONG SHRTWV IS ROUNDING BASE OF THE 5H TROF OVER SRN CA. TODAY INTO TONIGHT...ASSOC 290K ISENTROPIC LIFT AND 800-700 MB 2D FRONTOGENESIS AHEAD OF LEADING SHORTWAVE AIDING AREA OF -SN AND SOME -RA ACROSS LWR MI AND AND NRN WI. MODELS SUGGEST THAT BEST ISENTROPIC LIFT WITH THIS FEATURE WILL STAY SE OF CWA AND RADAR TRENDS SEEM TO SUPPORT THIS WITH BEST RETURNS OVER LWR MI. STILL MODEL QFP AMOUNTS OF .1 TO .2 INCH COULD RESULT IN INCH OR TWO OF SNOW. EXPECT GREATEST AMOUNTS OVER CENTRAL AND SE ZONES CLOSER TO BEST LIFT AND POSSIBLY AIDED BY UPSLOPE SE FLOW. LOOK FOR SNOW TO GENERALLY TAPER OFF BY EARLY AFT AS SHORTWAVE LIFTS NORTH OF AREA AND DNVA/SUBSIDENCE IN ITS WAKE RESULTS IN SOME DRYING IN 800-500 MB LYR PER ETA AND GFS FCST SNDGS. THIS DRY LYR ALOFT WILL DISRUPT ICE CRYSTAL NUCLEATION PROCESS (NO MSTR INTERSECTING -10 TO -15C ISOTHERMS) AND WILL PROBABLY RESULT IN SOME AREAS OF DZ/FZDZ THIS AFT. DRY LYR ALOFT PERSISTS INTO MUCH OF TONIGHT AND WITH ISENTROPIC LIFT AND SE FLOW (GENERALLY UPSLOPE FLOW FOR MUCH OF CWA) CONTINUING...LOOKS LIKE A GOOD SET UP FOR FZDZ/DZ EVENT. HAVE HIGHLIGHTED FZDZ IN NEW HWO. TUESDAY...UPPER LOW/SHRTWV CURRENTLY IN SOUTHERN CALIFORNIA EJECT NORTHEASTWARD INTO THE LOWER MIDWEST BY TUE MORNING. FOLLOWED UKMET SOLN WITH THIS SYSTEM WHICH IS A COMPROMISE OF MORE PHASED AND STRONGER ETA SOLN AND WEAKER AND MORE SRLY SOLN OF GFS. WITH SOME ISENTROPIC LIFT FCST AND UPR DIV IN RRQ OF 110 KT 3H JET KEPT IN LIKELY POPS FOR OVER ERN COUNTIES WITH GRADUALLY LESSER CHCS FOR PCPN TO THE WEST AWAY FM BETTER DYNAMICS. SNDG PROFILES SUGGEST RA/SN MIX OVER ERN AND CENTRAL ZONES WITH MOSTLY SN WEST. TUESDAY NIGHT...SYSTEM DEPARTS QUICKLY EAST OF FORECAST AREA IN THE EVENING WITH RDG BUILDING IN FM WEST OVERNIGHT. ETA MORE AGGRESSIVE WITH CAA BEHIND SYSTEM WITH 850MB TEMPS LOWREING TO -8C OVER LAKE SUPERIOR. THIS MIGHT BE ENOUGH TO GENERATE SOME LIGHT LAKE EFFECT SNOW ...DESPITE ANTICYCLONIC FLOW DEVELOPING IN THE EVENING. OTHERWISE EXPECT CHC OF -SN IN EVENING...THEN GENERALLY CLRG SKIES OVERNIGHT WITH RDGG/SUBSIDENCE BLDG IN. GENERALLY SIDED WITH COOLER ETA TEMPS FOR INTERIOR SECTIONS OF WEST...WHICH SHOWS LOWS DIPPING INTO MID TEENS OVER WI BDR. WEDNESDAY...DRY AND MILD DAY STILL ON TRACK WITH RETURN FLOW ALLOWING 850MB TEMPS TO WARM TO -2C BY MIDDAY. EXPECTING HIGH TEMPERATURES IN THE 30S...PER PREV FCST UNDER PARTLY SUNNY SKIES. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 900 PM CST MON DEC 6 2004 .DISCUSSION... WILL DROP THE FLOOD WATCH FOR THE SOUTHERN 1/3 OF CWA AS THE HEAVIEST RAIN SHIELD HAS ALREADY PASSED THROUGH ALL BUT THE FAR EAST CENTRAL COUNTIES AND HEAVY RAIN IS NO LONGER A THREAT. DOPPLER RADAR ESTIMATES SHOW UP TO A QUARTER OF AN INCH FELL FROM LINN COUNTY KS TO NORTH OF MARSHALL MO. A SECOND AREA OF EVEN LIGHT RAIN IS DEVELOPING IN THE DEFORMATION AREA OVER NORTHWEST OK NORTH OF THE MAIN VORT MAX NEAR CDS. 00Z ETA STRENGTHENS THE PVA ZONE ASSOCIATED WITH THIS FEATURE AND CURRENT RADAR TRENDS SUPPORT THIS. SO EXPECT TO SEE THE RAIN OVER NORTHWEST OK EXPAND A BIT AS IT SPREADS NORTHEAST AND BASICALLY TRACK ACROSS THE SAME AREA WHICH PICKED UP THE RAIN THIS EVENING. BUT QPF AMOUNTS SHOULD BE AROUND A TENTH OF AN INCH. WE HAVE ONE RIVER WHICH WENT ABOVE FLOOD STAGE THIS MORNING AND LATEST RFC GUIDANCE DOES NOT EXPECT ANY ADDITIONAL RIVERS TO GO INTO FLOOD. ALSO DROPPING MENTION OF THUNDER FROM FORECAST. WILL MENTION PATCHY DENSE FOG BUT NO ADVISORY AS I DO NOT EXPECT IT TO BECOME WIDESPREAD. UPSTREAM VISIBILITIES CURRENTLY IN THE 1-2SM RANGE. TOMORROWS AIRMASS WAS OVER CENTRAL NEBRASKA TODAY AND SOUNDINGS APPEAR TO SUPPORT SLIGHTLY COOLER TEMPERATURES THAN CURRENTLY FORECAST. WILL TRIM THEM BACK A FEW DEGREES. MJ && .PREV DISCUSSION... 312 PM... FORECAST CHALLENGE IN THE SHORT TERM IS NORTH AND WEST EXTENT OF RAIN AND THUNDERSTORMS TONIGHT. CURRENTLY WATCHING AN AREA OF SHOWERS AND THUNDERSTORMS OVER NORTHERN OKLAHOMA AND SOUTHEAST KANSAS...RACING NORTHEAST AT CLOSE TO 60 KTS. EXTRAPOLATION OF RADAR TRENDS INDICATES THIS RAIN REACHING THE SOUTHWEST PORTION OF THE FORECAST AREA BY 4 PM...AND THE SOUTHERN SUBURBS OF THE METRO BETWEEN 5 AND 6 PM. HAVE ADJUSTED WEATHER FORECAST TO ACCOMMODATE INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS ALONG AND SOUTH OF THE MISSOURI RIVER FOR EARLY THIS EVENING. THE MAIN QUESTION TONIGHT IS HOW PERSISTENT AND WIDESPREAD THE PRECIPITATION SHIELD WILL BECOME. OVERALL WENT WITH THE GFS/NGM SOLUTION WHICH KEEPS THE STRONGEST FORCING ALONG AND JUST NORTH OF THE I-44 CORRIDOR. THIS SEEMS REASONABLE GIVEN RADAR TRENDS OVER THE SOUTHERN PLAINS THIS AFTERNOON. PRECIPITABLE WATERS ARE PROGGED TO BE AROUND 0.75 TO 1 INCH ALONG THE FAR SOUTHERN TIER OF COUNTIES IN OUR FORECAST AREA. OVERALL AM NOT AS CONCERNED WITH THE HEAVY RAIN THREAT AS WE WERE FROM EARLIER RUNS. NONETHELESS...HEADWATER GUIDANCE ALONG THE SOUTHERN RIVERS ARE QUITE LOW...AND IT WOULD NOT TAKE MORE THAN A HALF INCH TO INCH OF RAIN TONIGHT TO PUSH SEVERAL RIVER POINTS INTO FLOOD. WILL LEAVE THE FLOOD WATCH OUT FOR TONIGHT AS IS...WITH THE STRONGEST EMPHASIS ON RIVER FLOODING POTENTIAL AS THE SYSTEM IS NOT SHAPING UP AS A FLASH FLOOD THREAT. CHANCES FOR THUNDER ACROSS THE SOUTHEASTERN HALF OF THE FORECAST AREA ALSO LOOK REASONABLE GIVEN CURRENT TRENDS AND PROGGED K-INDICES AT OR ABOVE 20C. ALSO EXPECT SOME FOG TO DEVELOP TO THE NORTH OF THE PRECIPITATION SHIELD ESPECIALLY EARLY...BUT AT THE MOMENT DO NOT EXPECT NEARLY AS WIDESPREAD OR DENSE A FOG AS LAST NIGHT. MADE LITTLE CHANGE TO OVERNIGHT LOWS FROM THE CURRENT FORECAST. EXPECT THE RAIN TO END FAIRLY QUICKLY TOMORROW MORNING FROM WEST TO EAST...AS VIGOROUS UPPER LEVEL LOW RACES EAST. SHOULD ALSO SEE SOME CLEARING...WHICH COUPLED WITH WEST WINDS WARRANTS A SUBTLE BOOST IN HIGHS TOMORROW. OTHERWISE...THE REMAINDER OF THE SHORT TERM LOOKS QUIET THROUGH MID-WEEK. DID BOOST HIGHS A TAD ON WEDNESDAY. HUDSON IN THE EXTENDED PORTION OF THE FORECAST...MEDIUM RANGE MODELS CONTINUE TO PROG THE DEVELOPMENT OF A HIGH AMPLITUDE TROUGH OVER THE EASTERN THIRD OF THE NATION AT THE END OF THE WEEK. AS THIS TROUGH BEGINS TO AMPLIFY OVER THE CENTRAL GREAT LAKES ON THURSDAY INTO FRIDAY...ANTICIPATE THE BULK OF THE SHORTWAVE ENERGY TO REMAIN TO THE NORTHEAST OF THE FORECAST AREA. HAVE DOWNGRADED POPS TO THE SLIGHT CHANCE CATEGORY ACROSS THE NORTHEAST HALF OF THE CWA. TEMPERATURES AT THE START OF THE PERIOD WILL BE ABOVE NORMAL...WITH HIGHS IN THE 50S EXPECTED ON THURSDAY. THE DEEPENING TROUGH ACROSS THE EASTERN STATES WILL REDUCE READINGS SLIGHTLY ACROSS NORTHEASTERN SECTIONS OF THE FORECAST AREA ON FRIDAY AND SATURDAY...ALTHOUGH TEMPERATURES WILL STILL BE ABOVE CLIMATOLOGICAL NORMALS FOR EARLY-MID DECEMBER. HAVE BUMPED UP SUNDAY MORNING LOWS...AS BREEZY SOUTHWEST WINDS DEVELOP AHEAD OF THE NEXT CLIPPER SYSTEM MOVING ACROSS THE UPPER MISSISSIPPI VALLEY. SCHMIT && .PREV DISCUSSION... 410 AM CST... MAIN FOCUS FOR THIS FORECAST IS FOG FOR THE MORNING HOURS AND RAIN/THUNDERSTORM CHANCES FOR THE LATE AFTERNOON AND EVENING HOURS. THE SHORTWAVE THAT BROUGHT SUNDAYS RAIN HAS SWEPT NORTHEAST ALONG WITH THE RAIN. FARTHER WEST...ANOTHER VIGOROUS SHORTWAVE IS BEGINNING TO PULL THROUGH THE DESERT SOUTHWEST. THIS SECOND WAVE WILL ARRIVE IN MISSOURI TONIGHT...PUSHING RAIN INTO THE CWA AHEAD OF IT. FOR FOG THIS MORNING...DESPITE HIGH CLOUDS AND WINDS THAT STARTED OUT IN THE 10 MPH RANGE...A WEAK SURFACE TROUGH HAS TAKEN UP RESIDENCE ACROSS THE NORTHERN HALF OF THE CWA IN THE WAKE OF THE SHORTWAVE THAT BROUGHT YESTERDAYS RAIN. CURRENT RUC/ETA/GFS MODEL RUNS SHOW THAT THE WEAK SURFACE TROUGH...AND ATTENDANT WEAK WINDS... WILL STICK AROUND THROUGH THE LATE MORNING HOURS...AND WHILE DENSE FOG HAS ONLY JUST STARTED DOMINATING THE WESTERN HALF OF THE CWA...IT IS EXPECTED TO SPREAD EAST AS WINDS CALM DOWN. A SUBSIDENCE INVERSION BEHIND THE EXITING SHORTWAVE HAS ONLY ENHANCED THE FOG PROBLEM. THEREFORE I HAVE HOISTED A DENSE FOG ADVISORY FOR THE ENTIRE CWA THROUGH NOON. THAT MIGHT PROVE TO BE A TOUCH TOO LONG IF THE TROUGH IN THE DESERT SOUTHWEST MOVES INTO THE MIDWEST ANY QUICKER THAN CURRENTLY FORECAST THOUGH. FOR THE AFTERNOON AND EVENING HOURS THE DESERT SOUTHWEST WAVE WILL MOVE THROUGH THE PLAINS...BRINGING WARMER TEMPS AND MORE RAIN TO THE FORECAST AREA. THE WAVE IS QUITE VIGOROUS AS EVIDENT IN THE SATELLITE IMAGERY TODAY...WHICH SHOWED AN ABUNDANCE OF CONVECTIVE CLOUD COVER IN THE BASE OF THE TROUGH. WINDS AHEAD OF THE TROUGH HAVE ALSO BEEN SUFFICIENT ACROSS THE SOUTHERN PLAINS TO ADVECT HIGHER DEW POINTS NORTH...WHICH HAS HAD THE EFFECT OF PUSHING TEMPS UP THROUGH THE OVERNIGHT HOURS...AND HAS ALSO CONTRIBUTED TO THE FOG THIS MORNING. GFS AND ETA DIFFER A LITTLE ON HOW THE WAVE WILL AFFECT OUR CWA...WITH THE UP SHOT IN THE DIFFERENCES BEING THAT THE GFS KEEPS THE HEAVIEST PRECIP FARTHER SOUTH WHILE THE ETA BRINGS IT IN ACROSS THE SOUTHEAST HALF OF THE CWA. PREFERENCE IS FOR THE ETA'S SOLUTION DESPITE THE GFS'S BETTER INITIALIZATION. THE GFS APPEARS TO BE SUFFERING SOME CONVECTIVE FEED BACK PROBLEMS AS IT MOVES INTO THE PLAINS...WHICH KEEPS THE SYSTEM A LITTLE TOO FAR SOUTH. ADDITIONALLY...THE ETA HAS SLOWED THE EJECTION OF THE SYSTEM DOWN BY 2 TO 3 HOURS...PUSHING THE RAIN MORE INTO THE EVENING HOURS. THIS LOOKS REASONABLE GIVEN THE CURRENT POSITION OF THE THE WAVE. FOR THE EVENING HOURS LIFTED INDICES DROP AS THE TROUGH MOVES IN...NEVER QUITE GOING NEGATIVE IN THE FORECAST AREA...BUT LOW POSITIVE VALUES OF 1 TO 2 INDICATE DESCENT INSTABILITY FOR EARLY DECEMBER. ADD THIS TO THE EARLIER SATELLITE OBSERVATION OF CONVECTIVE CLOUD COVER IN THE TROUGH...AND IT LOOKS LIKE THUNDERSTORMS WILL BE LIKELY FOR THE EVENING HOURS. ADDITIONALLY...QPF FOR THE EVENT COULD BE 1/2 TO 1 INCH OR MORE (ESPECIALLY WITH THE THUNDERSTORMS)...AND WITH THE HEADWATER GUIDANCE FOR EAST CENTRAL KANSAS THROUGH CENTRAL MISSOURI RUNNING IN THE 1/2 TO 1 INCH RANGE A FLOOD WATCH IN FOR THE EVENING HOURS...SAY 6 PM THROUGH 6 AM...LOOKS LIKE A GOOD IDEA. CUTTER && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE. MO...NONE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 312 PM CST MON DEC 6 2004 .DISCUSSION... FORECAST CHALLENGE IN THE SHORT TERM IS NORTH AND WEST EXTENT OF RAIN AND THUNDERSTORMS TONIGHT. CURRENTLY WATCHING AN AREA OF SHOWERS AND THUNDERSTORMS OVER NORTHERN OKLAHOMA AND SOUTHEAST KANSAS...RACING NORTHEAST AT CLOSE TO 60 KTS. EXTRAPOLATION OF RADAR TRENDS INDICATES THIS RAIN REACHING THE SOUTHWEST PORTION OF THE FORECAST AREA BY 4 PM...AND THE SOUTHERN SUBURBS OF THE METRO BETWEEN 5 AND 6 PM. HAVE ADJUSTED WEATHER FORECAST TO ACCOMMODATE INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS ALONG AND SOUTH OF THE MISSOURI RIVER FOR EARLY THIS EVENING. THE MAIN QUESTION TONIGHT IS HOW PERSISTENT AND WIDESPREAD THE PRECIPITATION SHIELD WILL BECOME. OVERALL WENT WITH THE GFS/NGM SOLUTION WHICH KEEPS THE STRONGEST FORCING ALONG AND JUST NORTH OF THE I-44 CORRIDOR. THIS SEEMS REASONABLE GIVEN RADAR TRENDS OVER THE SOUTHERN PLAINS THIS AFTERNOON. PRECIPITABLE WATERS ARE PROGGED TO BE AROUND 0.75 TO 1 INCH ALONG THE FAR SOUTHERN TIER OF COUNTIES IN OUR FORECAST AREA. OVERALL AM NOT AS CONCERNED WITH THE HEAVY RAIN THREAT AS WE WERE FROM EARLIER RUNS. NONETHELESS...HEADWATER GUIDANCE ALONG THE SOUTHERN RIVERS ARE QUITE LOW...AND IT WOULD NOT TAKE MORE THAN A HALF INCH TO INCH OF RAIN TONIGHT TO PUSH SEVERAL RIVER POINTS INTO FLOOD. WILL LEAVE THE FLOOD WATCH OUT FOR TONIGHT AS IS...WITH THE STRONGEST EMPHASIS ON RIVER FLOODING POTENTIAL AS THE SYSTEM IS NOT SHAPING UP AS A FLASH FLOOD THREAT. CHANCES FOR THUNDER ACROSS THE SOUTHEASTERN HALF OF THE FORECAST AREA ALSO LOOK REASONABLE GIVEN CURRENT TRENDS AND PROGGED K-INDICES AT OR ABOVE 20C. ALSO EXPECT SOME FOG TO DEVELOP TO THE NORTH OF THE PRECIPITATION SHIELD ESPECIALLY EARLY...BUT AT THE MOMENT DO NOT EXPECT NEARLY AS WIDESPREAD OR DENSE A FOG AS LAST NIGHT. MADE LITTLE CHANGE TO OVERNIGHT LOWS FROM THE CURRENT FORECAST. EXPECT THE RAIN TO END FAIRLY QUICKLY TOMORROW MORNING FROM WEST TO EAST...AS VIGOROUS UPPER LEVEL LOW RACES EAST. SHOULD ALSO SEE SOME CLEARING...WHICH COUPLED WITH WEST WINDS WARRANTS A SUBTLE BOOST IN HIGHS TOMORROW. OTHERWISE...THE REMAINDER OF THE SHORT TERM LOOKS QUIET THROUGH MID-WEEK. DID BOOST HIGHS A TAD ON WEDNESDAY. HUDSON IN THE EXTENDED PORTION OF THE FORECAST...MEDIUM RANGE MODELS CONTINUE TO PROG THE DEVELOPMENT OF A HIGH AMPLITUDE TROUGH OVER THE EASTERN THIRD OF THE NATION AT THE END OF THE WEEK. AS THIS TROUGH BEGINS TO AMPLIFY OVER THE CENTRAL GREAT LAKES ON THURSDAY INTO FRIDAY...ANTICIPATE THE BULK OF THE SHORTWAVE ENERGY TO REMAIN TO THE NORTHEAST OF THE FORECAST AREA. HAVE DOWNGRADED POPS TO THE SLIGHT CHANCE CATEGORY ACROSS THE NORTHEAST HALF OF THE CWA. TEMPERATURES AT THE START OF THE PERIOD WILL BE ABOVE NORMAL...WITH HIGHS IN THE 50S EXPECTED ON THURSDAY. THE DEEPENING TROUGH ACROSS THE EASTERN STATES WILL REDUCE READINGS SLIGHTLY ACROSS NORTHEASTERN SECTIONS OF THE FORECAST AREA ON FRIDAY AND SATURDAY...ALTHOUGH TEMPERATURES WILL STILL BE ABOVE CLIMATOLOGICAL NORMALS FOR EARLY-MID DECEMBER. HAVE BUMPED UP SUNDAY MORNING LOWS...AS BREEZY SOUTHWEST WINDS DEVELOP AHEAD OF THE NEXT CLIPPER SYSTEM MOVING ACROSS THE UPPER MISSISSIPPI VALLEY. SCHMIT && .PREV DISCUSSION... 410 AM CST... MAIN FOCUS FOR THIS FORECAST IS FOG FOR THE MORNING HOURS AND RAIN/THUNDERSTORM CHANCES FOR THE LATE AFTERNOON AND EVENING HOURS. THE SHORTWAVE THAT BROUGHT SUNDAYS RAIN HAS SWEPT NORTHEAST ALONG WITH THE RAIN. FARTHER WEST...ANOTHER VIGOROUS SHORTWAVE IS BEGINNING TO PULL THROUGH THE DESERT SOUTHWEST. THIS SECOND WAVE WILL ARRIVE IN MISSOURI TONIGHT...PUSHING RAIN INTO THE CWA AHEAD OF IT. FOR FOG THIS MORNING...DESPITE HIGH CLOUDS AND WINDS THAT STARTED OUT IN THE 10 MPH RANGE...A WEAK SURFACE TROUGH HAS TAKEN UP RESIDENCE ACROSS THE NORTHERN HALF OF THE CWA IN THE WAKE OF THE SHORTWAVE THAT BROUGHT YESTERDAYS RAIN. CURRENT RUC/ETA/GFS MODEL RUNS SHOW THAT THE WEAK SURFACE TROUGH...AND ATTENDANT WEAK WINDS... WILL STICK AROUND THROUGH THE LATE MORNING HOURS...AND WHILE DENSE FOG HAS ONLY JUST STARTED DOMINATING THE WESTERN HALF OF THE CWA...IT IS EXPECTED TO SPREAD EAST AS WINDS CALM DOWN. A SUBSIDENCE INVERSION BEHIND THE EXITING SHORTWAVE HAS ONLY ENHANCED THE FOG PROBLEM. THEREFORE I HAVE HOISTED A DENSE FOG ADVISORY FOR THE ENTIRE CWA THROUGH NOON. THAT MIGHT PROVE TO BE A TOUCH TOO LONG IF THE TROUGH IN THE DESERT SOUTHWEST MOVES INTO THE MIDWEST ANY QUICKER THAN CURRENTLY FORECAST THOUGH. FOR THE AFTERNOON AND EVENING HOURS THE DESERT SOUTHWEST WAVE WILL MOVE THROUGH THE PLAINS...BRINGING WARMER TEMPS AND MORE RAIN TO THE FORECAST AREA. THE WAVE IS QUITE VIGOROUS AS EVIDENT IN THE SATELLITE IMAGERY TODAY...WHICH SHOWED AN ABUNDANCE OF CONVECTIVE CLOUD COVER IN THE BASE OF THE TROUGH. WINDS AHEAD OF THE TROUGH HAVE ALSO BEEN SUFFICIENT ACROSS THE SOUTHERN PLAINS TO ADVECT HIGHER DEW POINTS NORTH...WHICH HAS HAD THE EFFECT OF PUSHING TEMPS UP THROUGH THE OVERNIGHT HOURS...AND HAS ALSO CONTRIBUTED TO THE FOG THIS MORNING. GFS AND ETA DIFFER A LITTLE ON HOW THE WAVE WILL AFFECT OUR CWA...WITH THE UP SHOT IN THE DIFFERENCES BEING THAT THE GFS KEEPS THE HEAVIEST PRECIP FARTHER SOUTH WHILE THE ETA BRINGS IT IN ACROSS THE SOUTHEAST HALF OF THE CWA. PREFERENCE IS FOR THE ETA'S SOLUTION DESPITE THE GFS'S BETTER INITIALIZATION. THE GFS APPEARS TO BE SUFFERING SOME CONVECTIVE FEED BACK PROBLEMS AS IT MOVES INTO THE PLAINS...WHICH KEEPS THE SYSTEM A LITTLE TOO FAR SOUTH. ADDITIONALLY...THE ETA HAS SLOWED THE EJECTION OF THE SYSTEM DOWN BY 2 TO 3 HOURS...PUSHING THE RAIN MORE INTO THE EVENING HOURS. THIS LOOKS REASONABLE GIVEN THE CURRENT POSITION OF THE THE WAVE. FOR THE EVENING HOURS LIFTED INDICES DROP AS THE TROUGH MOVES IN...NEVER QUITE GOING NEGATIVE IN THE FORECAST AREA...BUT LOW POSITIVE VALUES OF 1 TO 2 INDICATE DESCENT INSTABILITY FOR EARLY DECEMBER. ADD THIS TO THE EARLIER SATELLITE OBSERVATION OF CONVECTIVE CLOUD COVER IN THE TROUGH...AND IT LOOKS LIKE THUNDERSTORMS WILL BE LIKELY FOR THE EVENING HOURS. ADDITIONALLY...QPF FOR THE EVENT COULD BE 1/2 TO 1 INCH OR MORE (ESPECIALLY WITH THE THUNDERSTORMS)...AND WITH THE HEADWATER GUIDANCE FOR EAST CENTRAL KANSAS THROUGH CENTRAL MISSOURI RUNNING IN THE 1/2 TO 1 INCH RANGE A FLOOD WATCH IN FOR THE EVENING HOURS...SAY 6 PM THROUGH 6 AM...LOOKS LIKE A GOOD IDEA. CUTTER && .EAX WATCHES/WARNINGS/ADVISORIES... KS...FLOOD WATCH FROM 600 PM TONIGHT UNTIL 600 AM TUESDAY FOR LINN AND MIAMI COUNTY. MO...FLOOD WATCH FROM 600 PM TONIGHT UNTIL 600 AM TUESDAY ALONG AND SOUTH OF A HARRISONVILLE TO WAVERLY TO FAYETTE LINE. $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BILLINGS MT 845 PM MST MON DEC 6 2004 .SHORT TERM...VALID FOR TUE AND WED... LOW CLOUDS AND FOG HAVE CREPT INTO MILES CITY AND BAKER THIS EVENING. VISIBILITIES HAVE DROPPED TO A QUARTER MILE OR LESS AT BOTH LOCATIONS. CALLS AROUND TO SURROUNDING AREAS INDICATE THE FOG IS FAIRLY THICK ALONG INTERSTATE 94 AND ALONG HIGHWAY 12 IN CUSTER AND FALLON COUNTIES. THE ETA/GFS ARE USELESS AS THEY DEPICT FAIRLY DRY LOW LEVEL CONDITIONS ALL NIGHT. RUC SEEMS TO BE DOING BETTER AND ITS TREND OF LIFTING THE FOG/STRATUS NORTHEAST OF THE AREA BEFORE SUNRISE LOOKS REASONABLE BASED ON THE APPROACHING SYSTEM. HAVE ISSUED A DENSE FOG ADVISORY FOR THOSE TWO COUNTIES THROUGH 6 AM. CLOUDS AHEAD OF THE APPROACHING SYSTEM THIS EVENING ARE SPREADING EAST INTO THE CWA. THEY APPEAR TO BE FAIRLY THICK...SO WILL ADJUST CLOUD FORECAST TO READ MOSTLY CLOUDY TONIGHT. THE CLOUDS AND FOG WILL SLOW THE COOLING TONIGHT. FEEL CONFIDENT RAISING MIN TEMPERATURES SOME WHERE THE STRATUS AND FOG IS LOCATED...BUT THE CLOUDS SPREADING IN FROM THE WEST MAY BE HIGH ENOUGH TO ALLOW TEMPERATURE TO DROP TO FORECAST LOWS. WILL LEAVE AS IS. OTHER AREA OF CONCERN IS MOUNTAIN SNOW NEAR COOKE CITY. THE SYSTEM THAT IS HEADING THROUGH OREGAON AND IDAHO THIS EVENING IS BRING SNOW TO THOSE LOCATIONS. THE SYSTEM WILL SPLIT AND WEAKEN AS IT HEADS EAST...BUT IT STILL APPEARS THERE WILL BE ENOUGH MOISTURE FOR A COUPLE OF INCHES IN THE WEST FACING MOUNTAINS AND WILL LEAVE THE FORECAST AS IS. MOORE .LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON... GFS CONSISTENT FOR THE MOST PART AND HAVE MADE ONLY COSMETIC CHANGES TO GRIDS THROUGH FRIDAY. LIKELY POPS FOR MTNS THIS PERIOD AS FRONTOGENESIS...FAVORABLE LAPSE RATES AND JET FORCING SHOULD HELP OROGRAPHIC SNOWFALL. MIXING SHOULD BRING STRONG WINDS TO UPPER YELLOWSTONE VALLEY. DOWNSLOPE FLOW EXPECTED TO KEEP AREAS TO EAST DRY...BUT LATER SHIFTS MAY NEED TO MONITOR THIS. RIDGING ON FRIDAY AND ASSOCIATED SURFACE TROF DEVELOPS. SFC GRADIENT INCREASES AND BY FRIDAY NIGHT AND SATURDAY MORNING COULD SET UP DECENT GAP FLOW EVENT. WINDS ALREADY SET HIGH THIS PERIOD...BUT WILL NEED TO KEEP AN EYE ON THIS AS WEEK UNFOLDS AS PATTERN APPEARS FAVORABLE. MAY NEED TO BOOST TEMPS SATURDAY DUE TO DOWNSLOPE...BUT LEFT THIS FOR LATER SHIFTS TO CONSIDER. NEXT SYSTEM TO AFFECT AREA IS COLD FRONT BEING DRAGGED ALONG AS LOW PRESSURE MOVES OUT FROM ROCKIES. THIS STILL PROGGED TO DROP THROUGH AREA SATURDAY NIGHT. HAVE INTRODUCED SLGHT CHC POPS FURTHER ACROSS AREA AS RH AND FRONTAL ZONE SHOULD GIVE DECENT LIFT..THOUGH MOST ENERGY STAYS FURTHER EAST FOR NOW. THIS ALSO LINES UP BETTER WITH SURROUNDING OFFICES. ALSO...ENSEMBLE KEEPS MINIMUM TEMPS PRETTY LOW SUNDAY NIGHT. THIS MAKES SENSE AS WOULD EXPECT LIGHT WINDS AND CLEARI RADIATIONAL COOLING. SO TRENDED OVERNIGHT LOWS DOWN FOR THIS PERIOD. OTHERWISE EXTENDED PACKAGE IN GOOD SHAPE. TESAR && .PRELIMINARY POINT TEMP/POPS... TUE WED THU FRI SAT SUN MON ----------------------------------------------------------- BIL 024/044 028/047 033/044 031/047 030/048 028/043 025/042 00/E 00/N 00/N 00/B 00/N 20/B 00/B LVM 029/045 030/047 034/046 031/049 031/049 030/043 024/042 22/W 00/N 01/N 00/N 01/N 21/B 00/B HDN 021/044 028/047 029/046 030/049 029/049 026/044 023/043 00/B 00/B 00/N 00/B 00/B 20/B 00/B MLS 019/043 023/046 024/043 025/047 021/044 023/042 021/041 00/B 00/B 00/N 00/B 00/E 20/B 00/B 4BQ 017/046 024/048 026/046 026/049 025/047 021/044 018/043 00/B 00/B 00/N 00/B 00/B 20/B 00/B BHK 018/042 020/044 024/041 022/042 019/039 021/038 017/037 00/B 00/B 00/N 00/B 00/E 20/B 00/B SHR 018/043 022/046 028/045 025/048 021/048 022/046 019/045 00/B 00/B 00/B 00/B 00/N 20/B 00/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...DENSE FOG ADVISORY IN EFFECT UNTIL 6 AM MST TUESDAY FOR ZONES 32-33. WY...NONE. && $$ mt AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 851 PM EST MON DEC 6 2004 .SHORT TERM (REST OF TONIGHT)... WEAK UPPER LEVEL RIDGE OVER EASTERN USA...WITH CHANNELLED VORT MAXIMA MOVING NE THROUGH TN VALLEY. ISENTROPIC LIFT PRODUCING CLOUDS AND PRECIPITATION E OF TN VALLEY...BUT WITH MID LEVEL DRYING MOVING N INTO AREA...BACK EDGE OF PRECIPITAION SHIELD MOVING N INTO NC. AIR MASS REMAINS MOIST AND MARGINALLY UNSTABLE...SO WILL LEAVE CHANCE POPS IN OVERNIGHT...WITH A SLIGHT MAXIMA ALONG S FACING BLUE RIDGE ESCARPMENT ALONG BORDER OF NC MTS WITH GA/SC MTS. HAVE INTRODUCED THUNDER IN UPPER SAVANNAH RIVER VALLEY AS MESOETA CAPES EXCEED 200 J BRIEFLY. WITH PRECIP ENDING...AIR MASS MOIST...AND LOW ELEVATION WIND RATHER LIGHT...WILL INTRODUCE PATCHES OF DENSE FOG... INITIALLY BELOW 4000 FT...THEN BELOW 3000 FT. WIND TO INCREASE LATE TONIGHT AS HIGHER WINDS ALOFT AND TIGHTER GRADIENT MOVE INTO AREA FROM W. 19Z MESOETA APPEARED TO HAVE THE BEST HANDLE ON THIS. GREATEST WIND INCREASE WILL BE ABOVE 3000 FEET...WHERE GUSTS COULD EXCEED 35 MPH. MANY TEMPERATURES ACROSS AREA ARE ALREADY AT OR BELOW PREVIOUS MIN TEMPERATURE FORECAST...WITH SOME OF THE HIGHER TEMP AND DEW POINT OBSERVATIONS IN MTS. WITH AIR NEARLY SATURATED...DO NOT EXPECT MUCH MORE TEMP DECREASE. ADJUSTED TEMPS DOWN E OF MTS DEPENING ON CURRENT TEMP AND DEW POINT. ADJUSTED SOME HIGHER ELEVATION TEMPERATURES UP BASED ON CURRENT CONDITIONS AND WARM AIR ALOFT MOVING INTO AREA. UPDATED DEW POINTS FROM 21Z RUC...WHICH CAPTURED CURRENT SITUATION BEST. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 256 PM EST MON DEC 6 2004 SHORT TERM (TONIGHT THROUGH WEDNESDAY)... WIDESPREAD LIGHT TO MODERATE RAIN CONTINUES TO AFFECT MUCH OF THE MOUNTAINS OF THE WESTERN CAROLINAS ANDN NORTHEAST GEORGIA THIS AFTERNOON...WITH A SECONDARY AREA OF RAIN EXTENDING ALONG I-85 FROM SPARTANBURG TO CHARLOTTE METRO. THE HEAVIEST RAIN TODAY HAS BEEN IN THE SOUTHWEST NC MNTNS...WHERE UPSLOPE ENHANCEMENT HAS RESULTED IN ISOLATED STORM TOTAL AMOUNTS IN EXCESS OF AN INCH. AS THE UPPER JET/ LOW LEVEL BAROCLINIC ZONES CONTINUES TO RETREAT NORTH...AND MUCH DRIER MID LEVEL AIR NOTED TO OUR SOUTH ON 12Z ANALYSES ADVECTS INTO THE AREA THIS EVENING...EXPECT RAINFALL TO DIMINISH ACROSS THE REGION. IN FACT...AFTER A PERIOD OF LIKELY TO CATEGORICAL MOUNTAIN POPS THIS EVENING...WILL TAPER DOWN TO A TOKEN CHANCE OVERNIGHT. WILL CARRY HIGHER CHANCE POPS IN THE FAVORED SOUTHERLY UPSLOPE LATER TONIGHT...AS A 40-50 KNOT LLJ DEVELOPS IN ADVANCE OF APPROACHING FRONTAL BOUNDARY. POPS WILL INCREASE AGAIN BEGINNING TUE MORNING ACROSS THE WEST...AS FRONTAL BAND APPROACHES FROM THE TENN VALLEY. WITH THE ASSOCIATED SW TROUGH LIFTING WELL NORTH OF THE AREA...THERE WILL NOT BE A GREAT DEAL OF MID/UPPER FORCING WITH THIS FEATURE...AND THE MODELS DEPICT WANING LOW LEVEL FORCING WITH THE BOUNDARY AS IT MOVES INTO THE CWFA. POPS WERE INCREASED FROM THE PREVIOUS PACKAGE FOR THE TENN BORDER COUNTIES FOR TUE...BUT WERE LEFT AS IS FOR LOCATIONS EAST OF THERE. ANOTHER CONCERN FOR TOMORROW WILL BE WINDS...AS THE 40-50 KT JET IS EXPECTED TO PERSIST THROUGH THE MORNING HOURS. CONSIDERING THE WARM ADVECTIVE NATURE OF THE FLOW...DO NOT EXPECT MUCH IN THE WAY OF WIND PROBLEMS...EXCEPT PERHAPS IN THE HIGHEST ELEVATIONS. HOWEVER...WITH THE CWFA EXPECTED TO BE SOLIDLY IN THE WARM SECTOR... EVEN PIEDMONT LOCATIONS COULD SEE SOME RATHER HIGH YET NON-ADVISORY GUSTS WITH THE ONSET OF STRONGER MIXING TOMORROW MORNING. LONG TERM (WEDNESDAY NIGHT THROUGH MONDAY)... POPS INCREASE AGAIN FOR THURSDAY...AS FRONTAL BOUNDARY RETURNS NORTH IN RESPONSE TO A DIGGING SOUTHERN STREAM SYSTEM OVER THE PLAINS. THE CHANCE OF RAIN WILL CONTINUE FRI AS THE WAVE ALONG THE STALLED BOUNDARY MOVES EAST ACROSS THE AREA. NW FLOW INCREASES FRI NIGHT WITH LOW LEVEL MOISTURE DIVING TOWARD THE SRN APPALACHIANS AS AN AREA OF LOW PRES MOVES EAST OUT OF THE GREAT LAKES. THE HIGHER ELEVATIONS COULD SEE SCATTERED SNOW SHOWERS IN COLDER NW FLOW FRI NIGHT THROUGH SAT. HIGH PRESSURE BUILDS IN ON SUNDAY BEFORE A WEAK SFC BOUNDARY PUSHES THROUGH SUN NIGHT...BRINGING INCREASED MOISTURE...NW FLOW AND COOLER AIR TO THE REGION. A SLIGHT CHANCE OF RAIN IS EXPECTED OVER THE TN BORDER MTNS...POSSIBLY MIXING WITH SNOW OVER THE HIGHER ELEVATIONS. AVIATION... WITH ABUNDANT GULF MOISTURE AND GOOD ISENTROPIC LIFT...WIDESPREAD LOW CLOUDS WITH PERIODS OF RAIN AND RAIN SHOWERS WILL CONTINUE THROUGH THE EVENING HOURS BEFORE DEEPER MOISTURE MOVES NE AND RAIN TAPERS OFF. SFC WARM FRONT WILL SLOWLY PUSH NE...KEEPING REGION IN WARM...MOIST FLOW. MVFR...TEMPO IFR VIS/CIGS EXPECTED THROUGH THE LATE AFTERNOON...WITH IFR ALL LOCATIONS OVERNIGHT AND EARLY TUE MORNING. A BREAK IN RAINFALL AFTER MIDNIGHT WILL FILL IN WITH SHOWERS AROUND DAYBREAK AS A COLD FRONT APPROACHES FROM THE W. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SHORT TERM (UPDATE)...JAT sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 930 AM EST MON DEC 6 2004 .SHORT TERM /TODAY/...SEEMS THAT THE ETA DID QUITE WELL WITH ITS SUGGESTION OF THE COASTAL WARM FRONT THIS MORNING...WITH LIGHT NELY WINDS ACROSS MUCH OF THE FCST AREA. FRONT WILL REDEVELOP N OF THE AREA THIS AFTERNOON AS HIGH PRES IN THE ATLC SHIFTS FURTHER E. THIS WILL ALLOW FOR TEMPS TO WARM WELL ABOVE CLIMATOLOGICAL NORMALS...AS WINDS SHIFT TO SE AND S. CURRENT PATCHES OF LIGHT RAIN ACROSS THE CWA WILL TAPER OFF AND END. WILL WAIT UNTIL PRECIP GETS OUT OF THE AREA BEFORE SENDING AN UPDATE. WILL ALSO TWEAK COASTAL TEMPS AND WINDS TO ACCOUNT FOR COOLER INFLUX OFF THE ATLC. NRN TEMPS WILL BE LOWERED A FEW DEGREES DUE TO CONSIDERABLE CLOUD COVER. WILL ALSO CONSIDER GOING WITH PARTLY CLOUDY SKIES EXTREME S AS CLEARING IS NOT FAR TO THE WSW. && .MARINE...WMFNT OVER SRN PORTIONS OF THE WATERS TO CONTINUE MOVG N OVER ALL WATERS THRU THE AFTN HRS AND SHIFT WINDS ARND TO S-SE BY MIDDAY. RUC/M-ETA STRONGLY SHOW THIS SCENARIO WITH THE 06Z GFS A BIT MORE DIFFUSE WITH IT ALTHOUGH THE IDEA IS THERE. WILL ADJUST WORDING FOR WIND DIRECTIONS IN THE SC WATERS TO SE AND IN THE GA WATERS TO S. WIND SPEEDS LOOK GOOD...AS INITIALIZED WIND SPEEDS AND MSAS ANALYSES MATCH UP WELL WITH RUC/M-ETA SPEEDS. -SHRA ACTIVITY OVER THE WATERS STEADILY PUSHING OFF TO THE E WHILE ALSO SLOWLY DISSIPATING...THUS WILL NOT NEED TO CARRY ITS MENTION INTO THE AFTN FORECAST. WILL CONTINUE TO MONITOR THE POTENTIAL FOR AREAS OF/DENSE SEA FOG TNGT. 00Z/06Z GUIDANCE INDICATES WARM DEWPTS WILL MOVE OVER THE COOLER COASTAL AIR TNGT...PARTICULARLY WITHIN 5 NM OF THE COAST. WILL MAINTAIN FOG WORDING AS IS AND MAKE ANY NEEDED CHANGES WITH THE AFTN PKG. && .AVIATION...PRIMARILY VFR CONDS TO PERSIST THRU EARLY EVE WITH ONLY THICK MID AND HIGH LVL CIGS TO DEAL WITH. WILL STILL LOOK FOR FOG TO IMPACT BOTH TERMINALS AFTER 07/06Z TNGT AS IS ALREADY ADVERTISED. ISOLD -SHRA ACTIVITY GRADUALLY ENDING SO WILL NOT AMEND FOR IT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ 33/JPC sc AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 1136 AM CST MON DEC 6 2004 .DISCUSSION... UPDATED THE ZFP EARLIER AND ISSUED A DENSE FOG ADV FOR OUR SE QUARTER OF THE FA. SUNRISE IN ALL OF ITS GLORY...LOWERED VSBYS IN MOST LOCALES IN THAT AREA TO 1/4 MI TEMPORARILY. DECIDED TO KEEP IT GOING UNTIL 11 AM AS THAT IS WHEN THE RUC SNDGS SHOWED SOME DEG OF MIXING IN THE LOWEST LYR. FOG IS STILL PREVALENT ATTM NEARLY EVERYWHERE IN THE CWA...BUT THE DENSE FOG IS COOPERATING NICELY AND HAS GREATLY IMPROVED BETWEEN 10 AND 11AM. MANY SPOTS IN SW MN AND NW IA WERE REPORTING 1/4 MI OR LESS FOR A TIME AFT SUNRISE. WL UPDATE THE ZFP AGAIN AFT 11 AM TO ELIMINATE THE ADV. UPDATED SOME OF THE GRIDS...INCLUDING SKY COVER THRU TUESDAY. WHAT IS INTERESTING IS THAT THE SFC TROF AXIS REALLY NEVER MAKES IT THRU THIS AFTN FM THE JAMES VALLEY EWD. IN ELONGATES FM NW TO SE...AND SOME DRYING WLY FLOW UNDERCUTS THE SOUP AND EDGES EWD LATE THIS AFTN AND EVENING ALONG THE NEB/SD BORDER TOWARD KSUX. HOWEVER...AS THE OVERALL UPPER TROF EXITS LATE THIS EVENING...LOW LVL WINDS SHIFT AGAIN TO THE NNW DRAINING DOWN THE LOW STRATUS FM ND INTO THIS AREA...AND IT MAY BE A WHILE ON TUE BEFORE IT CLEARS OUT IN THE ERN HALF OF THE CWA. && .AVIATION... LOW STRATUS AND VISBYS CONTINUING TO CAUSE AVIATION PROBLEMS ACROSS CWA THIS AFTERNOON. WITH SOUTH-SOUTHEASTERLY FLOW AM NOT EXPECTING ANY OF THE TAF SITES TO CLEAR OUT OF THE CLOUDS COMPLETELY THIS AFTERNOON...ALTHOUGH CEILING HEIGHTS SHOULD CONTINUE TO SLOWLY RISE TO IFR-LOW MVFR RANGE THIS AFTERNOON. WORST CONDITIONS WILL BE AT FSD WHERE SOUTHEASTERLY FLOW WILL LOCK THE MOISTURE IN PLACE AND CIGS SHOULD NOT CLIMB OUT OF THE IFR RANGE. AFTER SUNSET CIGS SHOULD BEGIN TO LOWER AGAIN AND VISBYS WILL BEGIN TO FALL INTO THE 2-5SM RANGE PRIMARILY AT FSD AND NORTHEAST. CIGS WILL FALL BACK INTO THE IFR RANGE AFTER 06Z AT HON...AND INTO THE IFR/LIFR RANGE AT KSUX/KFSD. SOME INDICATIONS THAT STRATUS WILL BREAK AT SUX OVERNIGHT...IF THIS OCCURS CAN EXPECT IFR FG AND CIGS TO DEVELOP BUT ATTM AM NOT CONFIDENT ABOUT LOSS OF STRATUS. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ MJF/JRM sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 300 PM CST MON DEC 6 2004 .DISCUSSION...FORECAST FOCUS ON FOG TONIGHT...TIMING AND TYPE OF PRECIPITATION WITH APPROACHING STORM SYSTEM. IN THE SHORT TERM...WILL ISSUE A DENSE FOG ADVISORY FOR TONIGHT. COMBINATION OF MILD MOIST AIRMASS...CONTINUED MOISTURE ADVECTION OVERRIDING WARM FRONT SOUTH OF STATE AND LIGHT WIND FIELD WILL KEEP EXISTING FOG ONGOING TONIGHT. ETA/GFS/NGM/RUC PROGS IN CLOSE AGREEMENT TO BRING WIDESPREAD RAIN TO CWA AFTER MIDNIGHT WHICH MAY INCREASE VISIBILITIES. IN THE LONG TERM...ALL PROGS INTENSIFY LOW AS IT TRACKS SOUTH AND EAST OF REGION. NEVERTHELESS 850 MILLIBAR TEMPERATURE AND 1000/500 MILLIBAR PROGS DO NOT COLLAPSE FAST ENOUGH TO TURN RAIN OVER TO LIGHT SNOW EXCEPT IN WESTERN PORTIONS WHERE A RAIN/LIGHT SNOW MIX IS INDICATED BEFORE PRECIPITATION ENDS. IN THE LONG LONG TERM...ACTIVE WEATHER PATTERN CONTINUES INTO WEEKEND WITH FAST MOVING WEATHER SYSTEMS. && .MKX WATCHES/WARNING/ADVISORIES...DENSE FOG ADVISORY TONIGHT $$ ZAJDEL wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 345 AM EST TUE DEC 7 2004 .SHORT TERM... TODAY AND TONIGHT. GFS CONTINUED TREND TOWARD ETA SOLUTION FROM 24 HOURS AGO AND ALL MODELS IN GOOD AGREEMENT IN SHORT TERM. WITH HIGH DETAILED FORECAST ULTIMATELY WILL LOOK TO ETA/ETA12/RUC FOR GUIDANCE. MID LEVEL SHORTWAVE TO CUTOFF AND DEEPEN OVER 100M/12 HOURS TODAY AS IT TRACKS TO OUR NORTH REFLECTION FOUND IN 999 MB SURFACE LOW ACROSS EAST CENTRAL MISSOURI TO MOVE ACROSS NORTHWEST FORECAST AREA THIS AFTERNOON AND DEEPEN TO 990MB ACROSS LAKE HURON THIS EVENING. BEST 3 HOUR FALL/RISE ACROSS SOUTHERN/EASTERN FORECAST AREA AND HAVE GONE WITH WIND ADVISORY WITH LOW LEVEL LAPSE RATE MORE THAN 8 C/KM 750-950MB LAYER SHOULD BE SUFFICIENT TO MIX DOWN WINDS NEAR 50 MPH BY MIDDAY FAR SOUTHEAST ZONES. DEPENDING ON TIMING AND DRY SLOT ANY DECENT CLEARING COULD SPELL POTENTIAL NEED FOR AN UPGRADE FAR SOUTHEAST ZONES. FOR THIS MORNING THOUGH CLOUD TOPS NEAR M58C MID LEVEL LAPSE RATES NOT THAT IMPRESSIVE AND WILL NOT EXTEND OUR TSRA CHANCES ANY FURTHER NORTH...SLIGHTLY BETTER CHANCE LIES WITH SURFACE BASED CHANCES MIDDAY AHEAD OF COLD FRONT. FROPA WITH FALLING TEMPS LATER THIS AFTERNOON/EVENING AND CONTINUED MENTION OF POTENTIAL SW NORTH WITH 1000-850MB AND 8H TEMPS SUFFICIENT TO CHANGEOVER...SURFACE TEMPS/AMOUNTS SHOULD NOT ALLOW ANY ACCUMS. && .LONG TERM... WEDNESDAY THROUGH MONDAY THE LONG TERM WILL START OFF ON A QUIET NOTE FOR WED WITH SURFACE HIGH BUILDING INTO THE OHIO AND TENNESSEE VALLEY. SOUTHERLY RETURN FLOW ALREADY BEGINNING BY WED AFTERNOON WITH 925MB TEMPS REBOUNDING TO +2C TO +4C RANGE SUPPORTING MID TO UPPER 40S. MAY STILL BE SOME LINGERING LOW CLOUD IN THE MORNING...ESPECIALLY NORTH AND EAST BUT BOTH ETA/GFS SCOUR OUT LOW LEVEL MOISTURE AS THE SOUTHERLY RETURN FLOW BEGINS. HIGH CLOUDS BEGIN TO COME BACK IN WED NIGHT WITH RETURN OF MOISTURE IN WAA PATTERN AND SEVERAL WEAK SHORTWAVES RIDING UP THE WESTERN EDGE OF THE SOUTHEAST CONUS RIDGE. MORE SIGNIFICANT SHORTWAVE ENERGY BEGINS TO DIG SOUTHEAST THROUGH THE PLAINS ON THURSDAY. 00Z/7 ETA/GFS CONTINUE THE TREND OF KEEPING THE BEST DYNAMICS AND DEEP MOISTURE WEST OF THE CWA ON THURSDAY AND WILL CONTINUE WITH THE DRY FORECAST. AFTER THAT WE BEGIN TO SEE SOME INTERESTING FEATURES APPEARING IN THE MEDIUM RANGE MODEL GUIDANCE. POWERFUL PACIFIC JET SEEN ON WATER VAPOR EARLY THIS MORNING DRIVING EAST TOWARDS THE PACIFIC NORTHWEST AND SOUTHERN BC. THE REMNANTS OF TYPHOON NANMADOL HAVE MERGED WITH A STRONG EXTRATROPICAL LOW OVER THE ALEUTIANS. THIS STRONG SYSTEM WILL TURN THE FLOW SOUTHWEST OVER THE GULF OF ALASKA AND LEAD TO SIGNIFICANT DOWNSTREAM AMPLIFICATION OF THE FLOW PATTERN OVER NOAM BY FRIDAY. A SIGNIFICANT PIECE OF PACIFIC ENERGY WILL MOVE THROUGH THE NORTHERN ROCKIES AND BEGIN TO CARVE A TROUGH OUT OVER THE NORTHERN PLAINS BY THURSDAY WHILE A RIDGE BEGINS TO BUILD OVER THE WEST. BY FRIDAY ALL MEDIUM RANGE GUIDANCE IN OVERALL AGREEMENT IN DEVELOPING STRONG +PNA PATTERN WITH RIDGE CRESTING OVER THE WEST AND TROUGH DIGGING INTO THE OHIO VALLEY/GREAT LAKES. 12Z/6 ECMWF CONTINUES TO BE SHARPER WITH THE UPPER LEVEL TROUGH THAN THE GFS. AS TO BE EXPECTED...DIFFERENCES BEGIN TO SHOW UP IN GUIDANCE WITH REGARDS TO SURFACE FEATURES. 00Z/7 GFS IS FASTER/FURTHER NORTH/AND WEAKER WITH SURFACE LOW MOVING THROUGH THE REGION FRIDAY. THE ECMWF AND CANADIAN GEM ARE STRONGER AND FURTHER SOUTH WITH THE SURFACE LOW...WITH THE ECMWF BEING CONSIDERABLY SLOWER AS IT CLOSES OFF A MID LEVEL LOW OVER THE OHIO VALLEY. BOTH ECMWF AND CANADIAN GEM APPEAR TO BE REDEVELOPING A TRIPLE POINT SURFACE LOW TO ARRIVE AT THEIR STRONGER AND FURTHER SOUTH SOLUTIONS. THIS WOULD MAKE SENSE GIVEN THE AMOUNT OF ENERGY ROUNDING INTO THE DEVELOPING TROUGH. FOR NOW WILL RESPECT CONTINUITY OF GOING FORECAST UNTIL THE DETAILS CAN BE BETTER RESOLVED. WILL GO WITH CHANCE POPS FOR THURS NIGHT THROUGH FRIDAY NIGHT WITH INITIALLY RAIN...THEN RA/SN...THEN ALL SNOW. POTENTIAL IS CERTAINLY THERE FOR ACCUMULATING SNOW AT SOME POINT...BUT MANY QUESTIONS REMAIN TO BE ANSWERED. RATHER STRONG CLIPPER DROPS SOUTHEAST THROUGH THE MEAN FLOW ON SUNDAY. MODELS AGAIN IN GOOD OVERALL AGREEMENT ON KEEPING THIS SYSTEM NORTH OF THE CWA...ALLOWING A BRIEF WARMUP ON SUN. WILL CONTINUE WITH CHANCE RA/SN. BEHIND THE CLIPPER BOTH GFS/ECMWF BRING STRONG CAA AS A PIECE OF THE VERY COLD AIRMASS OVER NORTHERN CANADA IS DRAWN SOUTH. WILL CONTINUE TREND OF GOING BELOW GUIDANCE FOR MON WITH CHANCE POPS IN LAKE EFFECT COUNTIES. && .AVIATION... CIGS AT KSBN TO DROP WITH ONSET OF PCPN CURRENTLY ACROSS WEST CENTRAL INDIANA MOVING QUICKLY NORTHEAST AROUND 50-60KTS. LEFT TSRA AT KFWA WITH BETTER MID LEVEL LAPSE RATES TOWARD DAYBREAK. ADDED SOME DIFFERENTIATION WITH RESPECT TO FROPA LATER AT KFWA AND WITH BETTER LOW LEVEL LAPSE RATES MUCH HIGHER WINDS MIXING DOWN THIS AFTERNOON WITH 25KTS SUSTAINED GUST TO 35 KTS. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WIND ADVISORY FOR TODAY FOR ZONES INZ026>027...INZ033>034. WIND ADVISORY FOR TODAY FOR ZONES INZ006>009...INZ015>018... INZ022>025...INZ032. MI...WIND ADVISORY FOR TODAY FOR ZONES MIZ080>081. OH...WIND ADVISORY FOR TODAY FOR ZONES OHZ015>016...OHZ024>025. WIND ADVISORY FOR TODAY FOR ZONES OHZ001>002...OHZ004>005. && $$ MURPHY/HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 135 AM CST TUE DEC 7 2004 .UPDATE... THE LATEST SURFACE ANALYSIS SHOWS LOW PRESSURE CENTERED OVER MO. AN ASSOCIATED WARM FRONT EXTENDED EAST ALONG THE OHIO RIVER WITH AN ATTENDANT COLD FRONT ARCING SOUTHWESTWARD ACROSS ARKANSAS INTO EAST TX. IR SAT PICS SHOW COLDER TOPS ADVECTING INTO SEMO ATTM. REG RADAR LOOP SHOWS 40+ DBZ MOVING INTO SEMO WITH COLDER TOPS. THE LDS CHART ALSO INDICATED THUNDER ASSOCIATED WITH THE COLDER TOPS AND HIGHER DBZ RETURNS. THE RUC INITIALIZED THE BEST WITH THE SURFACE LOW ON THE 00Z TUE MODEL RUN...ALTHOUGH MOST OF THE MODELS WERE CLOSE AS WELL. THE RUC IS MUCH SLOWER WITH THE NE PROGRESSION OF THE SURFACE LOW AND THE GFS TAKES A MORE EASTERLY TRACK...DIVERGING FROM THE CONSENSUS. AGAIN THEY ARE ALL IN THE BALL PARK WHERE THE SHORT TERM IS CONCERNED. EVEN THOUGH THE ETA SHUNTS OFF ALL PRECIP BY 12Z THE SLOWER RUC AND WETTER GFS HOLDS SOME QPF IN THE FA. WILL PROBABLY MAINTAIN SOME TYPE OF POP THROUGH 15Z ESPECIALLY NORTH AND EAST. HOWEVER...WILL MONITOR RADAR AND MAKE A CALL CLOSER TO PRESS TIME. OTHERWISE MAIN CONCERN TODAY WILL BE WIND. MOS GUIDANCE AND WINDS ALOFT FORECAST INDICATE DECREASING WINDS BY AFTERNOON. IN CONTRAST WITH THE RUC BEING A BIT SLOWER AND THE RAPID INTENSIFICATION OF THE LOW FROM ALL MODELS WILL MENTION DECREASING WINDS IN THE AFTN ATTM. AFTER THE DEPARTURE OF THIS SYSTEM NOT A LOT TO TALK ABOUT. MODELS STILL INDICATE LATE WEEK SYSTEMS STILL STAYING SOUTH AND NORTH OF THE FA. CANT ARGUE WITH THE SLIGHT CHC SUNDAY. HOWEVER...SUCCESSIVE RUNS MAY YIELD A SIMILAR SOLUTION AS THE PREVIOUS CHC WE HAD FOR THURSDAY. MOS GUIDANCE HAS MAJOR DISCREPANCIES FIRST PERIOD WITH NEARLY A 10 DEGREE RANGE FOR HIGHS TODAY. THE MET HAD AROUND AN 8 DEGREE WARMUP FROM PREVIOUS RUN. THE MAV COOLED AROUND 5 DEGREES FROM PREVIOUS RUN. FWC REMAINED STEADY AT 60 WHICH IS CLOSE TO CURRENT GRIDS. HOWEVER...WILL TWEAK A LITTLE BIT WARMER TO FOLLOW TREND OF THE WARMER MAV AND MET. AFTER THE FIRST PERIOD MAV AND MET COME INTO RSNBL AGREEMENT BUT THE FWC STAYS A BIT COOLER. THUS WILL LEAN TOWARD THE MET/MAV SOLUTION AS THEY REFLECT CURRENT GRIDS BEST. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. && $$ KH ky AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 348 AM CST TUE DEC 7 2004 .DISCUSSION... SCREAMING MESSAGE ON THIS DAY IS REVEALED ON FOG DERIVED IMAGERY WITH WIDESPREAD LOW CLOUDS ESTABLISHED AND BECOMING MORE SO...BELOW FAIRLY FORMIDIBLE INVERSION BASED ON 00Z RAOBS. TROUGHING WITH MORE GENERAL LIFT NOW E OF CWA...ENHANCING DEVELOPMENT OF STG LOW PRESSURE IN MO INTO IL...WITH WK INVERTED TROUGH POKING NWWRD TO JUST E OF CWA...COLLAPSING SOMEWHAT SWRD AS CYCLONE DEEPENS. MAIN ISSUE IN SHORT TERM IS NOT WX...BUT RATHER PROPER DECREASE IN CLDS...AND THEN DEALING WITH NUMEROUS NON DIURNAL ELEMENTS TO TEMPERATURE FORECAST. TODAY...CLOUDS SHOULD ELIMINATE ANY SIGNIFICANT INSOLATION THRU MORNING AS LOW LVL CAA CONTINUES UNDER STRONG INVERSION. CAA GROSSLY OVERESTIMATED ON 00Z RUNS IF HANGING UP TMPS ARE INDICATION...AND LIKE RUC IDEA. DESPITE THIS...INDICATIONS OF CAA REMAIN WITH NLY LOWEST LVL FLOW COMPONENT THRU MIDDAY OVER ERN 2/3 OF CWA. THIS WL YIELD A SEMI NON DIURNAL TEMPERATURE TRACE FOR DAY AND FOR MUCH OF DAY MAY FIND DIFFICULT TO BE AS WARM AS CURRENT OBS. LIMITED RECOVERY EXPECTED ALL AREAS BY AFTERNOON...ESPLY WHERE LOW LVL CLEARING PUSHES INTO W...TIMED OUT WITH GRADIENT IN 950-925 HPA OISTURE...AND CLOSE TO WHERE BETTER SWLY FLUSHING GRADIENT...AS SHUD OT BE ABLE TO MIX OUT CLDS WELL DUE TO INITIAL THICKNESS. WL HAVE TO WATCH FOR SOME FOG ON WRN FLANK OF CLDS LTR THIS MORNING IN HIER TERRAIN OF SWRN CWA. TONIGHT...WL WATCH CLEARING CONTINUE TO WORK NEWRD WITH STRENGTHENING LOW LVL FLOW. WITH LACK OF MIXING AND INVERSION... WL HAVE RUNNING START TOWARD POTENTIAL FOG REDEVELOPMENT. HOWEVER... SFC GRADIENT WL BE INCREASING...AND MOISTURE REALLY DOES BECOME QUITE SHALLOW. MOISTURE AMT DECREASES WITH HT...SO MAY BE MORE OF A 3-5BR...MOST LKLY IN UPSLOPE ERN AREAS IF AT ALL. WL HAVE PLENTY OF HIGH CLOUDS AS WELL TO SLOW RADIATIONAL COOLING. LEADING HIGH CLDS WL LIMIT EARLY INSOLATION E WED...BUT SHUD END UP BEING FAIRLY DECENT MIXING DAY WITH TROUGH PASSAGE COOLING TMPS A BIT ALFT. FAIRLY CONSERVATIVE 925 HPA MIXING WOULD PUSH WARMING A BIT MORE EWRD THAN FORMER FCST...AND WL TAKE SEVERAL DEGREES UP ALG I29 CORRIDOR. WED NIGHT...WARMS MERRILY AWAY ALFT...WL HAVE ISSUES WITH WK FLOW INITIALLY HELPING TO SET UP STG ELEVATION DECOUPLING...AND WL FIT WIND AND TMPS TO THIS IDEA...ALLOWING FOR SOME WARMING TO OCCUR LTR IN NIGHT AS WARMING TMPS ALFT...INCREASING MID AND HIGH CLDS. SLNS BECOME FAIRLY DISPARATE BY WED NIGHT AND THU DEALING WITH TROUGH DIVING INTO NRN PLAINS...AND EFFECTS ARE SIGNIFICANT ON WINDS WED NIGHT...AND HOW MUCH IT MIGHT SATURATE. DESPITE DESERT ETA...DECIDED TO ADD IN LOW CHC POPS FOR FIRST HALF OF THU ACRS SWRN MN WITH WAA AND DECENT TROP IMPULSE OVERLAPPING. PS APPEAR TO WARM TOO MUCH TO ALLOW FOR ANY FROZEN PCPN...BUT MAY HAVE TO WATCH IF SFC TMPS DO NOT RESPOND FAST ENOUGH TO BRING ABV FREEZING. WL BE GREAT MIXING DAY...AND PUSHED TMPS TO MIDWAY 925-850 HPA POTENTIALS. BY FAR BEST COUPLING OF DYNAMICS WL BE EAST OF AREA BY AFTN AND EVNG. WITH UNCERTAINTY IN EXTENDED RANGE...BUT SUPPORT IN ECMWF/GFS FOR WARM TMPS SAT...WL KEEP AT LEAST AS WARM...ESPLY W. && .AVIATION... LOW STRATUS CONTS TO COVER THE ENTIRE AREA WITH CEILING GENERALLY AOB 1500FT. PATCHY FOG ALSO PREVAIL WITH VSBY GENERALLY 2 TO 5 MILES. THE FOG WILL DISSIPATE AFTER SUNRISE WITH NORTHWEST WINDS HELPING TO BREAK IT UP. LOW CLOUDS WILL BE BREAKING UP IN HON AREA AROUND 18Z AS DRIER AIR MOVES IN FROM WEST. HOWEVER LOW CLOUDS IN FSD AND SUX AREAS WILL NOT BE BREAKING UP UNTIL 22Z TO 00Z AS THE DRIER MOVES IN. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ CHAPMAN/WB sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 645 AM EST TUE DEC 7 2004 .AVIATION... SURFACE LOW MOVING QUICKLY NORTHEAST AND DEEPENING. LIFR CIGS AHEAD OF WARM FRONT AT FWA AND SBN TO START THEN MIXING OUT INTO MVFR WITH WINDS INCREASING. IMPRESSIVE FALL/RISE COUPLET WITH DEEPENING SYSTEM...AND WITH BETTER LOW LEVEL LAPSE RATES WILL CONTINUE WITH 25G35KT AT FWA. SOME CHANCE OF MIDDAY TSRA AT FWA WITH FROPA HOWEVER WITH CHANCES LOW HAVE NOT MENTIONED AT THIS TIME. && .SHORT TERM... TODAY AND TONIGHT. GFS CONTINUED TREND TOWARD ETA SOLUTION FROM 24 HOURS AGO AND ALL MODELS IN GOOD AGREEMENT IN SHORT TERM. WITH HIGH DETAILED FORECAST ULTIMATELY WILL LOOK TO ETA/ETA12/RUC FOR GUIDANCE. MID LEVEL SHORTWAVE TO CUTOFF AND DEEPEN OVER 100M/12 HOURS TODAY AS IT TRACKS TO OUR NORTH REFLECTION FOUND IN 999 MB SURFACE LOW ACROSS EAST CENTRAL MISSOURI TO MOVE ACROSS NORTHWEST FORECAST AREA THIS AFTERNOON AND DEEPEN TO 990MB ACROSS LAKE HURON THIS EVENING. BEST 3 HOUR FALL/RISE ACROSS SOUTHERN/EASTERN FORECAST AREA AND HAVE GONE WITH WIND ADVISORY WITH LOW LEVEL LAPSE RATE MORE THAN 8 C/KM 750-950MB LAYER SHOULD BE SUFFICIENT TO MIX DOWN WINDS NEAR 50 MPH BY MIDDAY FAR SOUTHEAST ZONES. DEPENDING ON TIMING AND DRY SLOT ANY DECENT CLEARING COULD SPELL POTENTIAL NEED FOR AN UPGRADE FAR SOUTHEAST ZONES. FOR THIS MORNING THOUGH CLOUD TOPS NEAR M58C MID LEVEL LAPSE RATES NOT THAT IMPRESSIVE AND WILL NOT EXTEND OUR TSRA CHANCES ANY FURTHER NORTH...SLIGHTLY BETTER CHANCE LIES WITH SURFACE BASED CHANCES MIDDAY AHEAD OF COLD FRONT. FROPA WITH FALLING TEMPS LATER THIS AFTERNOON/EVENING AND CONTINUED MENTION OF POTENTIAL SW NORTH WITH 1000-850MB AND 8H TEMPS SUFFICIENT TO CHANGEOVER...SURFACE TEMPS/AMOUNTS SHOULD NOT ALLOW ANY ACCUMS. && .LONG TERM... WEDNESDAY THROUGH MONDAY THE LONG TERM WILL START OFF ON A QUIET NOTE FOR WED WITH SURFACE HIGH BUILDING INTO THE OHIO AND TENNESSEE VALLEY. SOUTHERLY RETURN FLOW ALREADY BEGINNING BY WED AFTERNOON WITH 925MB TEMPS REBOUNDING TO +2C TO +4C RANGE SUPPORTING MID TO UPPER 40S. MAY STILL BE SOME LINGERING LOW CLOUD IN THE MORNING...ESPECIALLY NORTH AND EAST BUT BOTH ETA/GFS SCOUR OUT LOW LEVEL MOISTURE AS THE SOUTHERLY RETURN FLOW BEGINS. HIGH CLOUDS BEGIN TO COME BACK IN WED NIGHT WITH RETURN OF MOISTURE IN WAA PATTERN AND SEVERAL WEAK SHORTWAVES RIDING UP THE WESTERN EDGE OF THE SOUTHEAST CONUS RIDGE. MORE SIGNIFICANT SHORTWAVE ENERGY BEGINS TO DIG SOUTHEAST THROUGH THE PLAINS ON THURSDAY. 00Z/7 ETA/GFS CONTINUE THE TREND OF KEEPING THE BEST DYNAMICS AND DEEP MOISTURE WEST OF THE CWA ON THURSDAY AND WILL CONTINUE WITH THE DRY FORECAST. AFTER THAT WE BEGIN TO SEE SOME INTERESTING FEATURES APPEARING IN THE MEDIUM RANGE MODEL GUIDANCE. POWERFUL PACIFIC JET SEEN ON WATER VAPOR EARLY THIS MORNING DRIVING EAST TOWARDS THE PACIFIC NORTHWEST AND SOUTHERN BC. THE REMNANTS OF TYPHOON NANMADOL HAVE MERGED WITH A STRONG EXTRATROPICAL LOW OVER THE ALEUTIANS. THIS STRONG SYSTEM WILL TURN THE FLOW SOUTHWEST OVER THE GULF OF ALASKA AND LEAD TO SIGNIFICANT DOWNSTREAM AMPLIFICATION OF THE FLOW PATTERN OVER NOAM BY FRIDAY. A SIGNIFICANT PIECE OF PACIFIC ENERGY WILL MOVE THROUGH THE NORTHERN ROCKIES AND BEGIN TO CARVE A TROUGH OUT OVER THE NORTHERN PLAINS BY THURSDAY WHILE A RIDGE BEGINS TO BUILD OVER THE WEST. BY FRIDAY ALL MEDIUM RANGE GUIDANCE IN OVERALL AGREEMENT IN DEVELOPING STRONG +PNA PATTERN WITH RIDGE CRESTING OVER THE WEST AND TROUGH DIGGING INTO THE OHIO VALLEY/GREAT LAKES. 12Z/6 ECMWF CONTINUES TO BE SHARPER WITH THE UPPER LEVEL TROUGH THAN THE GFS. AS TO BE EXPECTED...DIFFERENCES BEGIN TO SHOW UP IN GUIDANCE WITH REGARDS TO SURFACE FEATURES. 00Z/7 GFS IS FASTER/FURTHER NORTH/AND WEAKER WITH SURFACE LOW MOVING THROUGH THE REGION FRIDAY. THE ECMWF AND CANADIAN GEM ARE STRONGER AND FURTHER SOUTH WITH THE SURFACE LOW...WITH THE ECMWF BEING CONSIDERABLY SLOWER AS IT CLOSES OFF A MID LEVEL LOW OVER THE OHIO VALLEY. BOTH ECMWF AND CANADIAN GEM APPEAR TO BE REDEVELOPING A TRIPLE POINT SURFACE LOW TO ARRIVE AT THEIR STRONGER AND FURTHER SOUTH SOLUTIONS. THIS WOULD MAKE SENSE GIVEN THE AMOUNT OF ENERGY ROUNDING INTO THE DEVELOPING TROUGH. FOR NOW WILL RESPECT CONTINUITY OF GOING FORECAST UNTIL THE DETAILS CAN BE BETTER RESOLVED. WILL GO WITH CHANCE POPS FOR THURS NIGHT THROUGH FRIDAY NIGHT WITH INITIALLY RAIN...THEN RA/SN...THEN ALL SNOW. POTENTIAL IS CERTAINLY THERE FOR ACCUMULATING SNOW AT SOME POINT...BUT MANY QUESTIONS REMAIN TO BE ANSWERED. RATHER STRONG CLIPPER DROPS SOUTHEAST THROUGH THE MEAN FLOW ON SUNDAY. MODELS AGAIN IN GOOD OVERALL AGREEMENT ON KEEPING THIS SYSTEM NORTH OF THE CWA...ALLOWING A BRIEF WARMUP ON SUN. WILL CONTINUE WITH CHANCE RA/SN. BEHIND THE CLIPPER BOTH GFS/ECMWF BRING STRONG CAA AS A PIECE OF THE VERY COLD AIRMASS OVER NORTHERN CANADA IS DRAWN SOUTH. WILL CONTINUE TREND OF GOING BELOW GUIDANCE FOR MON WITH CHANCE POPS IN LAKE EFFECT COUNTIES. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WIND ADVISORY FOR TODAY FOR ZONES INZ026>027...INZ033>034. WIND ADVISORY FOR TODAY FOR ZONES INZ006>009...INZ015>018... INZ022>025...INZ032. MI...WIND ADVISORY FOR TODAY FOR ZONES MIZ080>081. OH...WIND ADVISORY FOR TODAY FOR ZONES OHZ015>016...OHZ024>025. WIND ADVISORY FOR TODAY FOR ZONES OHZ001>002...OHZ004>005. && $$ MURPHY/HITCHCOCK in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1041 AM EST TUE DEC 7 2004 .DISCUSSION...DEEPENING 993MB SURFACE LOW WAS LIFTING NE INTO FAR SW LOWER MI LATE THIS MORNING. WIDESPREAD PRECIP WAS OCCURRING NORTH OF LOW. THIS WAS RAIN IN NORTHERN LOWER MI...AND A MIX OF JUST ABOUT EVERYTHING IN EASTERN UPPER. HEAVIEST PRECIP WITH THIS EVENT IS JUST GETTING UNDERWAY IN THE SW...AND WILL GRADUALLY SPREAD NE AS THE COMMA HEAD OF THE SYSTEM LIFTS ACROSS LOWER MI. PRECIP TYPE AND AMOUNTS ARE OF COURSE THE MAIN CHALLENGES FOR THIS AFTERNOON AND EVENING. SURFACE WILL CONTINUE NE TOWARD SOUTHERN LAKE HURON THIS AFTERNOON. DYNAMIC FORCING FOR PRECIP IS MAINLY ISENTROPIC LIFT (295K) EARLY...WITH 700-500MB DEFORMATION BECOMING A KEY PLAYER LATE THIS AFTERNOON INTO THE EVENING AS 500MB WAVE/COMMA HEAD MOVES THRU. WILL OBVIOUSLY CONTINUE WITH CATEGORICAL POPS. 06Z/12Z ETA/RUC RUNS ARE WARMER...AND STAY WARMER LONGER...THAN THE 00Z RUNS. THIS IS IN LINE WITH CURRENT OBS...WITH SOO ONTARIO REPORTING FZRA AND SLEET...AND SEVERAL REPORTS OF FZRA IN CHIPPEWA COUNTY. ETA/RUC SOUNDINGS THUR 21Z SUPPORT SNOW MIXING IN ONLY IN NW CHIP...WHERE 900MB TEMPS ONLY REACH +1C. ACROSS THE REST OF EASTERN UPPER...OBS/SOUNDINGS SUPPORT THE WARM NOSE ALOFT FILRY ESTABLISHING ITSELF...WITH 900MB TEMPS OF +2C OR HIGHER AND A 75MB DEEP MELTING LAYER. AND WITH TEMPS ONLY IN THE UPPER 20S (AND IN THE TEENS UPSTREAM IN ONTARIO)...THAT MEANS MAINLY FZRA. QPF FORECASTS ARE IN EXCESS OF A QUARTER INCH EAST OF I-75...AND THUS WILL UP HEADLINE TO WINTER STORM WARNING FOR CHIP. MORE RAIN AND LESS PRECIP TO THE SW...SO MACKINAC CAN STAY AS AN ADIVSORY...THOUGH FAR NE PARTS OF MACKINAC WILL PROBABLY SEE AROUND A QUARTER INCH OF FZRA. WILL ALSO BACK OFF A BIT ON CHANGEOVER TO SNOW IN NORTHERN LOWER MI THIS AFTERNOON. MODEL SOUNDINGS INDICATE THAT WON/T HAPPEN UNTIL AROUND DUSK. ZOLTOWSKI && .PREV DISCUSSION ISSUED 334 AM TUE DEC 7... LINGERING DEFORMATION PRECIP WILL PULL EAST OF THE AREA TOWARD MIDNIGHT...AS COLDER AIR ADVECTS SOUTH REMAINING PRECIP SHOULD GRADUALLY MIX WITH OR CHANGE TO SNOW DURING THE EVENING. WOULD NOT ANTICIPATE MUCH ADDITIONAL SNOW ACCUMULATION AFTER 00Z... PROBABLY AROUND AN INCH OR SO NORTH OF M-72. DEEP LAYER SUBSIDENCE DEVELOPS IN SYSTEM'S WAKE...SO MUCH OF THE PRECIP SHOULD COME TO AN END AROUND MIDNIGHT. OVERNIGHT...850MB TEMPERATURES FALL TO AROUND -6/-7C BY MORNING. INVERSION HEIGHTS CLIMB TO 850-875MB BUT STILL BELOW THE -10C ISOTHERM. SO ANY LAKE EFFECT THAT DEVELOPS SHOULD BE LIGHT AND SHALLOW...AND FOR NOW WILL ONLY CONFINE THIS TO AREAS AROUND WHITEFISH BAY THOUGH COULD SEE SOME FLURRIES OVER NORTHERN LOWER OVERNIGHT. MARINE...STRENGTHENING SURFACE LOW WILL GET WINDS CRANKING AGAIN FROM THE EAST/NORTHEAST TO START DAY...EVENTUALLY COMING AROUND TO NORTHWEST BY EVENING. WILL NEED AT LEAST SMALL CRAFT ADVISORIES ON THE LAKE MICHIGAN SIDE...AND GALE WARNINGS ON THE LAKE HURON SIDE AND THROUGH THE STRAITS. WINDS WILL GRADUALLY DIMINISH DURING THE OVERNIGHT. WEDNESDAY...WILL LINGER A FEW LIGHT SNOW SHOWERS/FLURRIES AROUND WHITEFISH BAY AND PARTS OF NORTHWEST LOWER DURING THE MORNING... OTHERWISE LOOKS LIKE A FAIRLY NICE DAY WITH SOME MORNING CLOUD COVER GIVING WAY TO SOME SUN BY AFTERNOON. NEXT SHORT WAVE IN THE SERIES WILL BE SLIDING THROUGH THE AREA WEDNESDAY NIGHT. BEST SHOT AT PRECIP ATTM LOOKS TO BE NORTH OF M-72 WHERE DEEPER MOISTURE FORECAST TO OCCUR (MID LEVELS REMAIN DRIER FARTHER SOUTH). MARINE...OTHER THAN PERHAPS EARLY IN THE DAY ON THE LAKE HURON SIDE WHERE THERE MAY BE SOME LINGERING SMALL CRAFT CONDITIONS...NOT EXPECTING HEADLINE CRITERIA WINDS AS NORTH-SOUTH ORIENTED SURFACE RIDGE SLIDES ACROSS THE FORECAST AREA THURSDAY AFTERNOON. WINDS WILL SHIFT FROM NORTHWEST AROUND TO THE SOUTH/SOUTHWEST DURING THE AFTERNOON. THURSDAY AND EXTENDED PERIODS...DID PULL POPS FROM THURSDAY WITH SHORT WAVE TROUGH EAST OF THE AREA BY THURSDAY MORNING. WILL KEEP AN EYE ON FRIDAY'S SYSTEM...FORECAST THICKNESSES SUGGEST A MIXED BAG OF PRECIP POSSIBLE ACROSS NORTHERN LOWER...WITH MAINLY SNOW ACROSS EASTERN UPPER. WON'T MAKE ANY CHANGES TO FRIDAY AT THIS POINT WITH GUIDANCE IN A STATE OF FLUX REGARDING SYSTEM EVOLUTION. && .APX...WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING... THROUGH MIDNIGHT...MIZ008. WINTER WEATHER ADVISORY...THROUGH MIDNIGHT...MIZ015. GALE WARNING...THROUGH MIDNIGHT...LHZ345>349. && $$ JPB mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BROWNSVILLE TX 827 AM CST TUE DEC 7 2004 .UPDATE... FRONTAL BOUNDARY HAS CROSSED THROUGH THE ENTIRE REGION WITH ONLY LIGHT DRIZZLE AT BEST. EARLY SATELLITE IMAGES SHOW THE CLEARING LINE IS NOT PROGRESSING EASTWARD ATTM WHICH COULD KEEP SKIES IN THE LOWER VALLEY FROM CLEARING BEFORE LATE AFTERNOON. WITH INITIALLY THICKER CLOUD COVER AND SLIGHT CAA, WILL NUDGE HIGH TEMPS DOWN A BIT. && .MARINE... BUOY 020 REPORTS SWELLS NEAR 6 FEET AND NORTH WINDS OF 20 TO 25 KNOTS. RUC MSL FIELDS AND SURFACE OBS INDICATE SOME SURFACE TROFFING EVIDENT JUST OFFSHORE ALONG THE OLD FRONT WHICH WILL MAINTAIN A PRETTY STRONG PRESSURE GRADIENT ALONG THE LOWER TEXAS COASTLINE THROUGHOUT THE MORNING. ACROSS THE BAY WATERS...MTRPIL REPORTS A NORTH WIND NEAR 13 KNOTS AND MAV AND MET PIL GUIDANCE KEEPS OVERALL WINDS BELOW SMALL CRAFT ADVISORY LEVELS. SO WILL MAINTAIN THE ADVISORY FOR THE OFFSHORE WATERS AND WILL MENTION SMALL CRAFT EXERCISE CAUTION ACROSS THE BAY WATERS. CURRENT OVERALL CWF WORDING LOOKS OK. && .AVIATION... VISIBILITIES AND CEILINGS ARE STEADILY IMPROVING AROUND THE LOWER RIO GRANDE VALLEY THIS MORNING AS DRIER LOWER LEVEL AIR CONTINUES TO FILTER INTO THE REGION. THE WESTERN PORTIONS OF THE BRO CWA ARE CLEAR AT THE MOMENT WITH THE LOWEST CEILINGS LOCATED AT THE BRO AIRPORT. DESPITE THE UPWARD TREND...THE REDUCED CEILINGS WILL LIKELY HOLD ON AROUND THE REGION THROUGHOUT THE MORNING AND EARLY AFTERNOON HOURS WITH OVERALL VFR CONDITIONS PREVAILING BY THIS AFTERNOON. WILL NEED TO MAKE ADJUSTMENTS TO THE TAF FORECAST WORDING MAINLY FOR CEILING TRENDS...BUT OVERALL FORECAST TRENDS LOOK OK FOR THE MOMENT. && .BRO WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 64/60 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1235 PM EST TUE DEC 7 2004 .AVIATION... SURFACE LOW OVER SOUTHWEST MICHIGAN MOVING QUICKLY NORTHEAST WITH COLD FRONT TO PASS KFWA NEAR START OF TAF PERIOD. WRAP AROUND LOW CLOUDS WILL WORK ACROSS TERMINALS FIRST HALF OF TONIGHT WITH SOME LAKE EFFECT CLOUDINESS AS WELL IN NW FLOW BUT NOT COLD ENOUGH FOR ANY LAKE EFFECT PRECIP. WINDS WILL GRADUALLY DIMINISH LATER THIS AFTERNOON AS SFC LOW PULLS AWAY AND RIDGEING MOVES IN FOR LATER TONIGHT AND WEDNESDAY. VFR CONDITIONS EXPECTED AFTER MIDNIGHT AT BOTH TERMINALS AS DRYER AIR WORKS IN AN WILL CONTINUE INTO WEDNESDAY. && .UPDATE... SFC LOW HEADING INTO SRN MI WITH COLD FRONT INTO WRN IN AND HEADING QUICKLY EAST. BULK OF RAIN WILL SHIFT NORTHEAST OUT OF CWA NEXT HOUR WITH ONLY SPOTTY RAIN IN BACKLASH. WINDS AND TEMPS LOOK GOOD FROM PREVIOUS FORECAST FOR NOW. CONCERNED MAX WINDS MAY HAVE ALREADY BEEN REACHED WITH MOST LOCATIONS JUST UNDER TO NEAR ADVISORY CRITERIA. MAY BE ABLE TO CANCEL ADVISORY WITH AFTERNOON PACKAGE. && .PREV DISCUSSION... TODAY AND TONIGHT. GFS CONTINUED TREND TOWARD ETA SOLUTION FROM 24 HOURS AGO AND ALL MODELS IN GOOD AGREEMENT IN SHORT TERM. WITH HIGH DETAILED FORECAST ULTIMATELY WILL LOOK TO ETA/ETA12/RUC FOR GUIDANCE. MID LEVEL SHORTWAVE TO CUTOFF AND DEEPEN OVER 100M/12 HOURS TODAY AS IT TRACKS TO OUR NORTH REFLECTION FOUND IN 999 MB SURFACE LOW ACROSS EAST CENTRAL MISSOURI TO MOVE ACROSS NORTHWEST FORECAST AREA THIS AFTERNOON AND DEEPEN TO 990MB ACROSS LAKE HURON THIS EVENING. BEST 3 HOUR FALL/RISE ACROSS SOUTHERN/EASTERN FORECAST AREA AND HAVE GONE WITH WIND ADVISORY WITH LOW LEVEL LAPSE RATE MORE THAN 8 C/KM 750-950MB LAYER SHOULD BE SUFFICIENT TO MIX DOWN WINDS NEAR 50 MPH BY MIDDAY FAR SOUTHEAST ZONES. DEPENDING ON TIMING AND DRY SLOT ANY DECENT CLEARING COULD SPELL POTENTIAL NEED FOR AN UPGRADE FAR SOUTHEAST ZONES. FOR THIS MORNING THOUGH CLOUD TOPS NEAR M58C MID LEVEL LAPSE RATES NOT THAT IMPRESSIVE AND WILL NOT EXTEND OUR TSRA CHANCES ANY FURTHER NORTH...SLIGHTLY BETTER CHANCE LIES WITH SURFACE BASED CHANCES MIDDAY AHEAD OF COLD FRONT. FROPA WITH FALLING TEMPS LATER THIS AFTERNOON/EVENING AND CONTINUED MENTION OF POTENTIAL SW NORTH WITH 1000-850MB AND 8H TEMPS SUFFICIENT TO CHANGEOVER...SURFACE TEMPS/AMOUNTS SHOULD NOT ALLOW ANY ACCUMS. LONG TERM... WEDNESDAY THROUGH MONDAY THE LONG TERM WILL START OFF ON A QUIET NOTE FOR WED WITH SURFACE HIGH BUILDING INTO THE OHIO AND TENNESSEE VALLEY. SOUTHERLY RETURN FLOW ALREADY BEGINNING BY WED AFTERNOON WITH 925MB TEMPS REBOUNDING TO +2C TO +4C RANGE SUPPORTING MID TO UPPER 40S. MAY STILL BE SOME LINGERING LOW CLOUD IN THE MORNING...ESPECIALLY NORTH AND EAST BUT BOTH ETA/GFS SCOUR OUT LOW LEVEL MOISTURE AS THE SOUTHERLY RETURN FLOW BEGINS. HIGH CLOUDS BEGIN TO COME BACK IN WED NIGHT WITH RETURN OF MOISTURE IN WAA PATTERN AND SEVERAL WEAK SHORTWAVES RIDING UP THE WESTERN EDGE OF THE SOUTHEAST CONUS RIDGE. MORE SIGNIFICANT SHORTWAVE ENERGY BEGINS TO DIG SOUTHEAST THROUGH THE PLAINS ON THURSDAY. 00Z/7 ETA/GFS CONTINUE THE TREND OF KEEPING THE BEST DYNAMICS AND DEEP MOISTURE WEST OF THE CWA ON THURSDAY AND WILL CONTINUE WITH THE DRY FORECAST. AFTER THAT WE BEGIN TO SEE SOME INTERESTING FEATURES APPEARING IN THE MEDIUM RANGE MODEL GUIDANCE. POWERFUL PACIFIC JET SEEN ON WATER VAPOR EARLY THIS MORNING DRIVING EAST TOWARDS THE PACIFIC NORTHWEST AND SOUTHERN BC. THE REMNANTS OF TYPHOON NANMADOL HAVE MERGED WITH A STRONG EXTRATROPICAL LOW OVER THE ALEUTIANS. THIS STRONG SYSTEM WILL TURN THE FLOW SOUTHWEST OVER THE GULF OF ALASKA AND LEAD TO SIGNIFICANT DOWNSTREAM AMPLIFICATION OF THE FLOW PATTERN OVER NOAM BY FRIDAY. A SIGNIFICANT PIECE OF PACIFIC ENERGY WILL MOVE THROUGH THE NORTHERN ROCKIES AND BEGIN TO CARVE A TROUGH OUT OVER THE NORTHERN PLAINS BY THURSDAY WHILE A RIDGE BEGINS TO BUILD OVER THE WEST. BY FRIDAY ALL MEDIUM RANGE GUIDANCE IN OVERALL AGREEMENT IN DEVELOPING STRONG +PNA PATTERN WITH RIDGE CRESTING OVER THE WEST AND TROUGH DIGGING INTO THE OHIO VALLEY/GREAT LAKES. 12Z/6 ECMWF CONTINUES TO BE SHARPER WITH THE UPPER LEVEL TROUGH THAN THE GFS. AS TO BE EXPECTED...DIFFERENCES BEGIN TO SHOW UP IN GUIDANCE WITH REGARDS TO SURFACE FEATURES. 00Z/7 GFS IS FASTER/FURTHER NORTH/AND WEAKER WITH SURFACE LOW MOVING THROUGH THE REGION FRIDAY. THE ECMWF AND CANADIAN GEM ARE STRONGER AND FURTHER SOUTH WITH THE SURFACE LOW...WITH THE ECMWF BEING CONSIDERABLY SLOWER AS IT CLOSES OFF A MID LEVEL LOW OVER THE OHIO VALLEY. BOTH ECMWF AND CANADIAN GEM APPEAR TO BE REDEVELOPING A TRIPLE POINT SURFACE LOW TO ARRIVE AT THEIR STRONGER AND FURTHER SOUTH SOLUTIONS. THIS WOULD MAKE SENSE GIVEN THE AMOUNT OF ENERGY ROUNDING INTO THE DEVELOPING TROUGH. FOR NOW WILL RESPECT CONTINUITY OF GOING FORECAST UNTIL THE DETAILS CAN BE BETTER RESOLVED. WILL GO WITH CHANCE POPS FOR THURS NIGHT THROUGH FRIDAY NIGHT WITH INITIALLY RAIN...THEN RA/SN...THEN ALL SNOW. POTENTIAL IS CERTAINLY THERE FOR ACCUMULATING SNOW AT SOME POINT...BUT MANY QUESTIONS REMAIN TO BE ANSWERED. RATHER STRONG CLIPPER DROPS SOUTHEAST THROUGH THE MEAN FLOW ON SUNDAY. MODELS AGAIN IN GOOD OVERALL AGREEMENT ON KEEPING THIS SYSTEM NORTH OF THE CWA...ALLOWING A BRIEF WARMUP ON SUN. WILL CONTINUE WITH CHANCE RA/SN. BEHIND THE CLIPPER BOTH GFS/ECMWF BRING STRONG CAA AS A PIECE OF THE VERY COLD AIRMASS OVER NORTHERN CANADA IS DRAWN SOUTH. WILL CONTINUE TREND OF GOING BELOW GUIDANCE FOR MON WITH CHANCE POPS IN LAKE EFFECT COUNTIES. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WIND ADVISORY FOR TODAY FOR ZONES INZ026>027...INZ033>034. WIND ADVISORY FOR TODAY FOR ZONES INZ006>009...INZ015>018... INZ022>025...INZ032. MI...WIND ADVISORY FOR TODAY FOR ZONES MIZ080>081. OH...WIND ADVISORY FOR TODAY FOR ZONES OHZ015>016...OHZ024>025. WIND ADVISORY FOR TODAY FOR ZONES OHZ001>002...OHZ004>005. && $$ in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1145 AM EST TUE DEC 7 2004 .UPDATE... SFC LOW HEADING INTO SRN MI WITH COLD FRONT INTO WRN IN AND HEADING QUICKLY EAST. BULK OF RAIN WILL SHIFT NORTHEAST OUT OF CWA NEXT HOUR WITH ONLY SPOTTY RAIN IN BACKLASH. WINDS AND TEMPS LOOK GOOD FROM PREVIOUS FORECAST FOR NOW. CONCERNED MAX WINDS MAY HAVE ALREADY BEEN REACHED WITH MOST LOCATIONS JUST UNDER TO NEAR ADVISORY CRITERIA. MAY BE ABLE TO CANCEL ADVISORY WITH AFTERNOON PACKAGE. && .AVIATION... SURFACE LOW MOVING QUICKLY NORTHEAST AND DEEPENING. LIFR CIGS AHEAD OF WARM FRONT AT FWA AND SBN TO START THEN MIXING OUT INTO MVFR WITH WINDS INCREASING. IMPRESSIVE FALL/RISE COUPLET WITH DEEPENING SYSTEM...AND WITH BETTER LOW LEVEL LAPSE RATES WILL CONTINUE WITH 25G35KT AT FWA. SOME CHANCE OF MIDDAY TSRA AT FWA WITH FROPA HOWEVER WITH CHANCES LOW HAVE NOT MENTIONED AT THIS TIME. && .PREV DISCUSSION... TODAY AND TONIGHT. GFS CONTINUED TREND TOWARD ETA SOLUTION FROM 24 HOURS AGO AND ALL MODELS IN GOOD AGREEMENT IN SHORT TERM. WITH HIGH DETAILED FORECAST ULTIMATELY WILL LOOK TO ETA/ETA12/RUC FOR GUIDANCE. MID LEVEL SHORTWAVE TO CUTOFF AND DEEPEN OVER 100M/12 HOURS TODAY AS IT TRACKS TO OUR NORTH REFLECTION FOUND IN 999 MB SURFACE LOW ACROSS EAST CENTRAL MISSOURI TO MOVE ACROSS NORTHWEST FORECAST AREA THIS AFTERNOON AND DEEPEN TO 990MB ACROSS LAKE HURON THIS EVENING. BEST 3 HOUR FALL/RISE ACROSS SOUTHERN/EASTERN FORECAST AREA AND HAVE GONE WITH WIND ADVISORY WITH LOW LEVEL LAPSE RATE MORE THAN 8 C/KM 750-950MB LAYER SHOULD BE SUFFICIENT TO MIX DOWN WINDS NEAR 50 MPH BY MIDDAY FAR SOUTHEAST ZONES. DEPENDING ON TIMING AND DRY SLOT ANY DECENT CLEARING COULD SPELL POTENTIAL NEED FOR AN UPGRADE FAR SOUTHEAST ZONES. FOR THIS MORNING THOUGH CLOUD TOPS NEAR M58C MID LEVEL LAPSE RATES NOT THAT IMPRESSIVE AND WILL NOT EXTEND OUR TSRA CHANCES ANY FURTHER NORTH...SLIGHTLY BETTER CHANCE LIES WITH SURFACE BASED CHANCES MIDDAY AHEAD OF COLD FRONT. FROPA WITH FALLING TEMPS LATER THIS AFTERNOON/EVENING AND CONTINUED MENTION OF POTENTIAL SW NORTH WITH 1000-850MB AND 8H TEMPS SUFFICIENT TO CHANGEOVER...SURFACE TEMPS/AMOUNTS SHOULD NOT ALLOW ANY ACCUMS. LONG TERM... WEDNESDAY THROUGH MONDAY THE LONG TERM WILL START OFF ON A QUIET NOTE FOR WED WITH SURFACE HIGH BUILDING INTO THE OHIO AND TENNESSEE VALLEY. SOUTHERLY RETURN FLOW ALREADY BEGINNING BY WED AFTERNOON WITH 925MB TEMPS REBOUNDING TO +2C TO +4C RANGE SUPPORTING MID TO UPPER 40S. MAY STILL BE SOME LINGERING LOW CLOUD IN THE MORNING...ESPECIALLY NORTH AND EAST BUT BOTH ETA/GFS SCOUR OUT LOW LEVEL MOISTURE AS THE SOUTHERLY RETURN FLOW BEGINS. HIGH CLOUDS BEGIN TO COME BACK IN WED NIGHT WITH RETURN OF MOISTURE IN WAA PATTERN AND SEVERAL WEAK SHORTWAVES RIDING UP THE WESTERN EDGE OF THE SOUTHEAST CONUS RIDGE. MORE SIGNIFICANT SHORTWAVE ENERGY BEGINS TO DIG SOUTHEAST THROUGH THE PLAINS ON THURSDAY. 00Z/7 ETA/GFS CONTINUE THE TREND OF KEEPING THE BEST DYNAMICS AND DEEP MOISTURE WEST OF THE CWA ON THURSDAY AND WILL CONTINUE WITH THE DRY FORECAST. AFTER THAT WE BEGIN TO SEE SOME INTERESTING FEATURES APPEARING IN THE MEDIUM RANGE MODEL GUIDANCE. POWERFUL PACIFIC JET SEEN ON WATER VAPOR EARLY THIS MORNING DRIVING EAST TOWARDS THE PACIFIC NORTHWEST AND SOUTHERN BC. THE REMNANTS OF TYPHOON NANMADOL HAVE MERGED WITH A STRONG EXTRATROPICAL LOW OVER THE ALEUTIANS. THIS STRONG SYSTEM WILL TURN THE FLOW SOUTHWEST OVER THE GULF OF ALASKA AND LEAD TO SIGNIFICANT DOWNSTREAM AMPLIFICATION OF THE FLOW PATTERN OVER NOAM BY FRIDAY. A SIGNIFICANT PIECE OF PACIFIC ENERGY WILL MOVE THROUGH THE NORTHERN ROCKIES AND BEGIN TO CARVE A TROUGH OUT OVER THE NORTHERN PLAINS BY THURSDAY WHILE A RIDGE BEGINS TO BUILD OVER THE WEST. BY FRIDAY ALL MEDIUM RANGE GUIDANCE IN OVERALL AGREEMENT IN DEVELOPING STRONG +PNA PATTERN WITH RIDGE CRESTING OVER THE WEST AND TROUGH DIGGING INTO THE OHIO VALLEY/GREAT LAKES. 12Z/6 ECMWF CONTINUES TO BE SHARPER WITH THE UPPER LEVEL TROUGH THAN THE GFS. AS TO BE EXPECTED...DIFFERENCES BEGIN TO SHOW UP IN GUIDANCE WITH REGARDS TO SURFACE FEATURES. 00Z/7 GFS IS FASTER/FURTHER NORTH/AND WEAKER WITH SURFACE LOW MOVING THROUGH THE REGION FRIDAY. THE ECMWF AND CANADIAN GEM ARE STRONGER AND FURTHER SOUTH WITH THE SURFACE LOW...WITH THE ECMWF BEING CONSIDERABLY SLOWER AS IT CLOSES OFF A MID LEVEL LOW OVER THE OHIO VALLEY. BOTH ECMWF AND CANADIAN GEM APPEAR TO BE REDEVELOPING A TRIPLE POINT SURFACE LOW TO ARRIVE AT THEIR STRONGER AND FURTHER SOUTH SOLUTIONS. THIS WOULD MAKE SENSE GIVEN THE AMOUNT OF ENERGY ROUNDING INTO THE DEVELOPING TROUGH. FOR NOW WILL RESPECT CONTINUITY OF GOING FORECAST UNTIL THE DETAILS CAN BE BETTER RESOLVED. WILL GO WITH CHANCE POPS FOR THURS NIGHT THROUGH FRIDAY NIGHT WITH INITIALLY RAIN...THEN RA/SN...THEN ALL SNOW. POTENTIAL IS CERTAINLY THERE FOR ACCUMULATING SNOW AT SOME POINT...BUT MANY QUESTIONS REMAIN TO BE ANSWERED. RATHER STRONG CLIPPER DROPS SOUTHEAST THROUGH THE MEAN FLOW ON SUNDAY. MODELS AGAIN IN GOOD OVERALL AGREEMENT ON KEEPING THIS SYSTEM NORTH OF THE CWA...ALLOWING A BRIEF WARMUP ON SUN. WILL CONTINUE WITH CHANCE RA/SN. BEHIND THE CLIPPER BOTH GFS/ECMWF BRING STRONG CAA AS A PIECE OF THE VERY COLD AIRMASS OVER NORTHERN CANADA IS DRAWN SOUTH. WILL CONTINUE TREND OF GOING BELOW GUIDANCE FOR MON WITH CHANCE POPS IN LAKE EFFECT COUNTIES. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...WIND ADVISORY FOR TODAY FOR ZONES INZ026>027...INZ033>034. WIND ADVISORY FOR TODAY FOR ZONES INZ006>009...INZ015>018... INZ022>025...INZ032. MI...WIND ADVISORY FOR TODAY FOR ZONES MIZ080>081. OH...WIND ADVISORY FOR TODAY FOR ZONES OHZ015>016...OHZ024>025. WIND ADVISORY FOR TODAY FOR ZONES OHZ001>002...OHZ004>005. && $$ in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1250 PM EST TUE DEC 7 2004 .DISCUSSION...QUICK UPDATE TO ADD ISOLATED THUNDER TO THE SOUTH... GIVEN RECENT LIGHTNING STRIKES NEAR CADILLAC. THIS IS HAPPENING IN AREA OF CONVECTIVE-LOOKING CLOUD TOPS ON SATELLITE...AND WITH ETA SHOWING STEEP LAPSE RATES ABOVE 800MB. THIS WILL BE VERY BRIEF...BY 21Z WE/RE COOLING OFF IN THE LOWER LEVELS...AND INSTABILITY IS GONE. EARLIER DISCUSSION FOLLOWS... DEEPENING 993MB SURFACE LOW WAS LIFTING NE INTO FAR SW LOWER MI LATE THIS MORNING. WIDESPREAD PRECIP WAS OCCURRING NORTH OF LOW. THIS WAS RAIN IN NORTHERN LOWER MI...AND A MIX OF JUST ABOUT EVERYTHING IN EASTERN UPPER. HEAVIEST PRECIP WITH THIS EVENT IS JUST GETTING UNDERWAY IN THE SW...AND WILL GRADUALLY SPREAD NE AS THE COMMA HEAD OF THE SYSTEM LIFTS ACROSS LOWER MI. PRECIP TYPE AND AMOUNTS ARE OF COURSE THE MAIN CHALLENGES FOR THIS AFTERNOON AND EVENING. SURFACE WILL CONTINUE NE TOWARD SOUTHERN LAKE HURON THIS AFTERNOON. DYNAMIC FORCING FOR PRECIP IS MAINLY ISENTROPIC LIFT (295K) EARLY...WITH 700-500MB DEFORMATION BECOMING A KEY PLAYER LATE THIS AFTERNOON INTO THE EVENING AS 500MB WAVE/COMMA HEAD MOVES THRU. WILL OBVIOUSLY CONTINUE WITH CATEGORICAL POPS. 06Z/12Z ETA/RUC RUNS ARE WARMER...AND STAY WARMER LONGER...THAN THE 00Z RUNS. THIS IS IN LINE WITH CURRENT OBS...WITH SOO ONTARIO REPORTING FZRA AND SLEET...AND SEVERAL REPORTS OF FZRA IN CHIPPEWA COUNTY. ETA/RUC SOUNDINGS THUR 21Z SUPPORT SNOW MIXING IN ONLY IN NW CHIP...WHERE 900MB TEMPS ONLY REACH +1C. ACROSS THE REST OF EASTERN UPPER...OBS/SOUNDINGS SUPPORT THE WARM NOSE ALOFT FILRY ESTABLISHING ITSELF...WITH 900MB TEMPS OF +2C OR HIGHER AND A 75MB DEEP MELTING LAYER. AND WITH TEMPS ONLY IN THE UPPER 20S (AND IN THE TEENS UPSTREAM IN ONTARIO)...THAT MEANS MAINLY FZRA. QPF FORECASTS ARE IN EXCESS OF A QUARTER INCH EAST OF I-75...AND THUS WILL UP HEADLINE TO WINTER STORM WARNING FOR CHIP. MORE RAIN AND LESS PRECIP TO THE SW...SO MACKINAC CAN STAY AS AN ADIVSORY...THOUGH FAR NE PARTS OF MACKINAC WILL PROBABLY SEE AROUND A QUARTER INCH OF FZRA. WILL ALSO BACK OFF A BIT ON CHANGEOVER TO SNOW IN NORTHERN LOWER MI THIS AFTERNOON. MODEL SOUNDINGS INDICATE THAT WON/T HAPPEN UNTIL AROUND DUSK. ZOLTOWSKI && .PREV DISCUSSION ISSUED 334 AM TUE DEC 7... LINGERING DEFORMATION PRECIP WILL PULL EAST OF THE AREA TOWARD MIDNIGHT...AS COLDER AIR ADVECTS SOUTH REMAINING PRECIP SHOULD GRADUALLY MIX WITH OR CHANGE TO SNOW DURING THE EVENING. WOULD NOT ANTICIPATE MUCH ADDITIONAL SNOW ACCUMULATION AFTER 00Z... PROBABLY AROUND AN INCH OR SO NORTH OF M-72. DEEP LAYER SUBSIDENCE DEVELOPS IN SYSTEM'S WAKE...SO MUCH OF THE PRECIP SHOULD COME TO AN END AROUND MIDNIGHT. OVERNIGHT...850MB TEMPERATURES FALL TO AROUND -6/-7C BY MORNING. INVERSION HEIGHTS CLIMB TO 850-875MB BUT STILL BELOW THE -10C ISOTHERM. SO ANY LAKE EFFECT THAT DEVELOPS SHOULD BE LIGHT AND SHALLOW...AND FOR NOW WILL ONLY CONFINE THIS TO AREAS AROUND WHITEFISH BAY THOUGH COULD SEE SOME FLURRIES OVER NORTHERN LOWER OVERNIGHT. MARINE...STRENGTHENING SURFACE LOW WILL GET WINDS CRANKING AGAIN FROM THE EAST/NORTHEAST TO START DAY...EVENTUALLY COMING AROUND TO NORTHWEST BY EVENING. WILL NEED AT LEAST SMALL CRAFT ADVISORIES ON THE LAKE MICHIGAN SIDE...AND GALE WARNINGS ON THE LAKE HURON SIDE AND THROUGH THE STRAITS. WINDS WILL GRADUALLY DIMINISH DURING THE OVERNIGHT. WEDNESDAY...WILL LINGER A FEW LIGHT SNOW SHOWERS/FLURRIES AROUND WHITEFISH BAY AND PARTS OF NORTHWEST LOWER DURING THE MORNING... OTHERWISE LOOKS LIKE A FAIRLY NICE DAY WITH SOME MORNING CLOUD COVER GIVING WAY TO SOME SUN BY AFTERNOON. NEXT SHORT WAVE IN THE SERIES WILL BE SLIDING THROUGH THE AREA WEDNESDAY NIGHT. BEST SHOT AT PRECIP ATTM LOOKS TO BE NORTH OF M-72 WHERE DEEPER MOISTURE FORECAST TO OCCUR (MID LEVELS REMAIN DRIER FARTHER SOUTH). MARINE...OTHER THAN PERHAPS EARLY IN THE DAY ON THE LAKE HURON SIDE WHERE THERE MAY BE SOME LINGERING SMALL CRAFT CONDITIONS...NOT EXPECTING HEADLINE CRITERIA WINDS AS NORTH-SOUTH ORIENTED SURFACE RIDGE SLIDES ACROSS THE FORECAST AREA THURSDAY AFTERNOON. WINDS WILL SHIFT FROM NORTHWEST AROUND TO THE SOUTH/SOUTHWEST DURING THE AFTERNOON. THURSDAY AND EXTENDED PERIODS...DID PULL POPS FROM THURSDAY WITH SHORT WAVE TROUGH EAST OF THE AREA BY THURSDAY MORNING. WILL KEEP AN EYE ON FRIDAY'S SYSTEM...FORECAST THICKNESSES SUGGEST A MIXED BAG OF PRECIP POSSIBLE ACROSS NORTHERN LOWER...WITH MAINLY SNOW ACROSS EASTERN UPPER. WON'T MAKE ANY CHANGES TO FRIDAY AT THIS POINT WITH GUIDANCE IN A STATE OF FLUX REGARDING SYSTEM EVOLUTION. && .APX...WATCHES/WARNINGS/ADVISORIES...WINTER STORM WARNING... THROUGH MIDNIGHT...MIZ008. WINTER WEATHER ADVISORY...THROUGH MIDNIGHT...MIZ015. GALE WARNING...THROUGH MIDNIGHT...LHZ345>349. && $$ JPB mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 1210 PM EST TUE DEC 7 2004 .UPDATE... MAIN CONCERN IS HEAVY RAIN/MINOR FLOODING THIS AFTERNOON. 88D STORM TOTAL PCPN PRODUCT IS INDICATING THAT AS MUCH AS 3 INCHES OF RAIN HAS ALREADY FALLEN IN A BAND FROM WHITEHALL TO BIG RAPIDS. THIS IS THE AREA OF BEST MID LEVEL FGEN FORCING AND DEFORMATION. WE HAVE BEEN UNABLE TO FIND ANY GROUND TRUTH TO THIS ESTIMATION... AND WOULD ATTRIBUTE THE EXAGGERATED AMOUNTS TO RADAR BRIGHT-BANDING. THE MELTING LEVEL IS AROUND 6K FEET... AND 6K FEET IS ABOUT WHERE THE RADAR BEAM IS AT FROM WHITEHALL TO BIG RAPIDS. BOTTOM LINE...THERE IS SIGNIFICANT RAINFALL OCCURRING ACROSS THE NW PORTION OF THE CWFA... BUT NOT AS MUCH AS OUR STORM TOTAL PCPN PRODUCT INDICATES. MODELS SHOW BEST FGEN FORCING LIFTING NORTH AND EAST THIS AFTERNOON... SO AM NOT ANTICIPATING MUCH MORE THAN MINOR NUISANCE FLOODING. SOME RISES IN THE RIVERS CAN BE EXPECTED... AND THAT WAS ADDRESSED EARLIER IN A HYDROLOGIC/RIVER STATEMENT (RVSGRR). THE SURFACE LOW IS NEAR AZO ATTM AT 992 MB...AND LATEST RUC HAS IT DEEPENING TO 988 AS IT MOVES NE. STILL SOME CONCERN THAT WIND GUSTS WILL APPROACH ADVISORY CRITERIA IN THE SE CORNER OF THE CWFA WHERE DEEPER MIXING IS EXPECTED IN THE WARM SECTOR. IT WILL BE VERY CLOSE...BUT WILL LET THIS BE HANDLED IN THE HWO. ANY CONVECTION MAY ALSO BE ABLE TO MIX DOWN SOME STRONGER WIND GUSTS. && .GRR WATCHES/WARNINGS/ADVISORIES...SMALL CRAFT ADVISORY...NEW BUFFALO TO MANISTEE. && $$ MEADE mi AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA NATIONAL WEATHER SERVICE SIOUX FALLS SD 1145 AM CST TUE DEC 7 2004 .DISCUSSION... MAIN CHANGES TO THE FORECAST ARE TO SKY COVER AND TEMPS FOR THIS AFTERNOON. LOW CLOUDS HAVE BEEN NEARLY STATIONARY AS WARM FRONT ACROSS SOUTHWEST SD. THINK MODELS ARE OVERDOING THE LOW LEVEL DRYING IN THIS RATHER SLOW MOVING PATTERN...BUT THINK ONCE LOW GET ORGANIZED ACROSS WESTERN SD EARLY AFTERNOON THAT WARM FRONT WILL SURGE NORTHWARD ENOUGH TO CLEAR OUT EXTREME SOUTHWEST CWA BEFORE CLEARING CONTINUES TO THE NORTHEAST. TEMPS FORECAST LOOKED GOOD IN THE EAST WHERE STRATUS WILL REMAIN IN PLACE AND TEMPS ARE SLOW TO CLIMB...BUT NOT SURE WE WILL SEE A DRAMATIC WARMUP IN THE WEST AND KNOCKED ABOUT 5 DEGREES OF GOING HIGHS...AND THIS MAY BE A BIT TO OPTIMISTIC. .PREV DISCUSSION... SCREAMING MESSAGE ON THIS DAY IS REVEALED ON FOG DERIVED IMAGERY WITH WIDESPREAD LOW CLOUDS ESTABLISHED AND BECOMING MORE SO...BELOW FAIRLY FORMIDIBLE INVERSION BASED ON 00Z RAOBS. TROUGHING WITH MORE GENERAL LIFT NOW E OF CWA...ENHANCING DEVELOPMENT OF STG LOW PRESSURE IN MO INTO IL...WITH WK INVERTED TROUGH POKING NWWRD TO JUST E OF CWA...COLLAPSING SOMEWHAT SWRD AS CYCLONE DEEPENS. MAIN ISSUE IN SHORT TERM IS NOT WX...BUT RATHER PROPER DECREASE IN CLDS...AND THEN DEALING WITH NUMEROUS NON DIURNAL ELEMENTS TO TEMPERATURE FORECAST. TODAY...CLOUDS SHOULD ELIMINATE ANY SIGNIFICANT INSOLATION THRU MORNING AS LOW LVL CAA CONTINUES UNDER STRONG INVERSION. CAA GROSSLY OVERESTIMATED ON 00Z RUNS IF HANGING UP TMPS ARE INDICATION...AND LIKE RUC IDEA. DESPITE THIS...INDICATIONS OF CAA REMAIN WITH NLY LOWEST LVL FLOW COMPONENT THRU MIDDAY OVER ERN 2/3 OF CWA. THIS WL YIELD A SEMI NON DIURNAL TEMPERATURE TRACE FOR DAY AND FOR MUCH OF DAY MAY FIND DIFFICULT TO BE AS WARM AS CURRENT OBS. LIMITED RECOVERY EXPECTED ALL AREAS BY AFTERNOON...ESPLY WHERE LOW LVL CLEARING PUSHES INTO W...TIMED OUT WITH GRADIENT IN 950-925 HPA OISTURE...AND CLOSE TO WHERE BETTER SWLY FLUSHING GRADIENT...AS SHUD OT BE ABLE TO MIX OUT CLDS WELL DUE TO INITIAL THICKNESS. WL HAVE TO WATCH FOR SOME FOG ON WRN FLANK OF CLDS LTR THIS MORNING IN HIER TERRAIN OF SWRN CWA. TONIGHT...WL WATCH CLEARING CONTINUE TO WORK NEWRD WITH STRENGTHENING LOW LVL FLOW. WITH LACK OF MIXING AND INVERSION... WL HAVE RUNNING START TOWARD POTENTIAL FOG REDEVELOPMENT. HOWEVER... SFC GRADIENT WL BE INCREASING...AND MOISTURE REALLY DOES BECOME QUITE SHALLOW. MOISTURE AMT DECREASES WITH HT...SO MAY BE MORE OF A 3-5BR...MOST LKLY IN UPSLOPE ERN AREAS IF AT ALL. WL HAVE PLENTY OF HIGH CLOUDS AS WELL TO SLOW RADIATIONAL COOLING. LEADING HIGH CLDS WL LIMIT EARLY INSOLATION E WED...BUT SHUD END UP BEING FAIRLY DECENT MIXING DAY WITH TROUGH PASSAGE COOLING TMPS A BIT ALFT. FAIRLY CONSERVATIVE 925 HPA MIXING WOULD PUSH WARMING A BIT MORE EWRD THAN FORMER FCST...AND WL TAKE SEVERAL DEGREES UP ALG I29 CORRIDOR. WED NIGHT...WARMS MERRILY AWAY ALFT...WL HAVE ISSUES WITH WK FLOW INITIALLY HELPING TO SET UP STG ELEVATION DECOUPLING...AND WL FIT WIND AND TMPS TO THIS IDEA...ALLOWING FOR SOME WARMING TO OCCUR LTR IN NIGHT AS WARMING TMPS ALFT...INCREASING MID AND HIGH CLDS. SLNS BECOME FAIRLY DISPARATE BY WED NIGHT AND THU DEALING WITH TROUGH DIVING INTO NRN PLAINS...AND EFFECTS ARE SIGNIFICANT ON WINDS WED NIGHT...AND HOW MUCH IT MIGHT SATURATE. DESPITE DESERT ETA...DECIDED TO ADD IN LOW CHC POPS FOR FIRST HALF OF THU ACRS SWRN MN WITH WAA AND DECENT TROP IMPULSE OVERLAPPING. PS APPEAR TO WARM TOO MUCH TO ALLOW FOR ANY FROZEN PCPN...BUT MAY HAVE TO WATCH IF SFC TMPS DO NOT RESPOND FAST ENOUGH TO BRING ABV FREEZING. WL BE GREAT MIXING DAY...AND PUSHED TMPS TO MIDWAY 925-850 HPA POTENTIALS. BY FAR BEST COUPLING OF DYNAMICS WL BE EAST OF AREA BY AFTN AND EVNG. WITH UNCERTAINTY IN EXTENDED RANGE...BUT SUPPORT IN ECMWF/GFS FOR WARM TMPS SAT...WL KEEP AT LEAST AS WARM...ESPLY W. && .AVIATION... LO CLDS WILL HAVE A HARD DTIME GOING OUT IN DECRG LO LVL FLOW. HEATG THIS AFTN WILL ERODE CLDS SWRN CWA BUT NOT UP TO TAF AREA. WILL HAVE TO WAIT FOR MIXG LATR TNGT...AND THIS LOOKS FORCEFUL ENUF TO CLR SKIES LATE TNGT MAINLY 06Z-12Z IN HON\FSD\SUX AREA. EXPCT MVFR BR OF 3 TO E MI AT HON TO IMPRV BY 20Z. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ JRM/WILLIAMS sd