AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 710 PM EST TUE NOV 30 2004 .AVIATION/UPDATE... BAROCLINIC LEAF GENERATION WELL UNDERWAY ACRS REGION THIS EVENING IN RESPONSE TO INTENSE UPR SYS ALOFT OVR MO. SFC CYCLONE OVR WRN KY ABOUT TO BOMB AS IT HEADS FOR WRN LK ERIE BY MORNING IN ASSOCN/W VERY INTENSE HGT FALLS SPREADING EWD THIS EVENING AND IN CONJUNCTION W/EMERGING TROP FOLD NOW CROSSING INTO SW IL. ATTM BROAD PCPN SHIELD W/IFR/LIFR CIGS IN PLACE W/INTENSIFYING WAA AHD OF UPR SYS W/MID LVL DEFORMATION BAND TAKING SHAPE FM ERN MO INTO WRN IL. SHRT TERM DILEMMA CONTS TO BE WHEN CHANGE OVR WILL OCCUR AND RESULTANT SNOW AMTS. ACARS ASCENT SOUNDINGS OUT OF ORD STILL QUITE WARM W/MELTING LYR STILL TOO DEEP TO SPRT SNOW IN CURRENT ADVISORY AREA FOR SOME TIME BUT DEEP FORCED ASCENT AHD OF DEEPENING MID LVL CIRC WORRISOME IN CONTEXT OF A RAPID CHANGE OVR GIVEN MARGINAL WET BULB TEMP PROFILE UP THROUGH 850MB. ALREADY CHANGE OVR LINE INTO WRN SUBURBS OF CHICAGO AS OF 23Z AND EXTRAPOLATION PUTS IT INTO SBN NR 04Z. THIS ALONG W/21Z RUC INDICATIONS OF SIG BANDED PCPN EVENT WITHIN INTENSELY FRONTOGENETICAL MID LVL DEFORMATION AXIS SURE ARGUES FOR GOING ADVISORY W/6HR QPFS OVER ONE HALF INCH AND PERHAPS SOME EXPANSION S AND E TO INCLUDE ANOTHER ROW OF COUNTIES. RFD REPORTING 3 INCHES IN THE LAST 2 HOURS. ONLY THING KEEPING AN UPGRADE TO A WARNING IS PROGGED RAPID EJECTION NEWD OVERNIGHT BUT GOING TO BE A CLOSE CALL. NEEDLESS TO SAY THIS WILL KEEP SBN AND FWA IN THE SOUP OVERNIGHT W/CHANGE OVER AT FWA BY 07Z. RAPID IMPROVEMENT EXPECTED AFT 12Z. UPDATED ZONES WITH SNOW ADVISORY EXPANSION OUT BY 830 PM. && .PREV DISCUSSION... .SHORT TERM... TONIGHT AND WEDNESDAY. BROAD/PERSISTENT 290K ISENT LIFT CONTINUES WITH RAIN WIDESPREAD THROUGH CWA AT ISSUANCE TIME. UPPER LOW ACROSS FAR EASTERN KANSAS EJECTING ENE INTO SOUTHERN GREAT LAKES OVERNIGHT. SURFACE LOW AND INITIAL STRENGTH OF UPPER SYSTEM TENDS TO FAVOR 12Z ETA. WITH GFS TOO FAR EAST WITH SURFACE LOW/WEAKER MORE OPEN MIDLEVEL WAVE. HAVE TRENDED TOWARD AN ETA SOLUTION BUT TEMPERED A BIT AS SOME CONCERN OVER INITIAL WARM NEAR SURFACE TEMPS. WET BULB PROFILE IMPROVES BY 03Z FAR NORTHWEST ZONES AND DEPTH OF ABOVE FREEZING LAYER MAY BE OVERCOME BY DYNAMIC COOLING WITH STRONG UPLIFT WITH 7H LOW DEEPENING OVER 100 METERS/12 HRS WITH TRACK NEAR IN/MI LINE. FAVORABLE DENDRITIC LAYER IN MAX UVM AND GOOD MOISTURE BUT ONLY FOR BRIEF TIME FRAME...GENERALLY AROUND 3HRS AS SYSTEM QUICKLY TRAVERSES CWA. WET SNOWFALL RATES AROUND AN INCH/HOUR POSSIBLE GIVEN STRONG LIFT/DEFORMATION SETUP WITH NORTHWEST CWA BEST AREA TARGETED. WILL GO WITH SNOW ADVISORY OVERNIGHT WITH 3-5 MOST ANTICIPATED...SOME ZONES WITH 2-4 INCHES WITH ADVISORY WITH HAZARD POTENTIAL/IMPACT ENOUGH TO WARRANT A HEADLINE. SYSTEM PULLS OUT EAST RAPIDLY TUESDAY...HAVE GONE A FEW BLO AVNMOS WITH SNOW FOR TUESDAY. && .LONG TERM... WEDNESDAY NIGHT THROUGH TUESDAY...THE FIRST SHORTWAVE WILL BE MOVING OUT OF THE REGION WEDNESDAY AS COLD AIR SPREADS OVER THE AREA BEHIND THIS SYSTEM. HAVE KEPT A CHANCE FOR LAKE EFFECT SNOW SHOWERS IN THURSDAY AFTERNOON AND THURSDAY NIGHT AS FORECAST 850 MB TEMPS DROP TO -10C BY LATE THURSDAY. THIS DOES NOT APPEAR TO BE A VERY FAVORABLE SET UP FOR LAKE EFFECT SNOW AS DELTA T'S ARE MARGINAL AND TRAJECTORIES ARE MORE WESTERLY. ALSO...WINDS SHOULD BACK THURSDAY NIGHT MORE TO THE WEST OR SW WITH INVERSION HEIGHTS DROPPING BELOW 3000 FEET ACCORDING TO GFS BUFKIT...SO HAVE REMOVED THE CHANCE FOR LAKE EFFECT SNOW FRIDAY. HOWEVER...NEXT SHORTWAVE SHOULD MOVE ACROSS THE GREAT LAKES FRIDAY NIGHT...SO HAVE A CHANCE FOR SNOW FRIDAY NIGHT INTO EARLY SATURDAY. GFS LOW LEVEL THICKNESSES BETWEEN 1000 AND 850 MB WELL BELOW 1300M INDICATE SNOW...SO HAVE KEPT THE PCPN ALL SNOW. FOR THE REST OF SATURDAY THROUGH TUESDAY...TEMPERATURES SHOULD WARM ABOVE NORMAL AHEAD OF THE NEXT SYSTEM. GFS AND CANADIAN ENSEMBLES INDICATE A RATHER BROAD TROF OVER THE CENTRAL CONUS EARLY NEXT WEEK WITH SOME TROFS EJECTING EAST...TIMING OF WHICH IS EXTREMELY UNCERTAIN. THEREFORE HAVE A CHANCE FOR RAIN OR SNOW MONDAY INTO TUESDAY WITH TEMPERATURES ABOVE NORMAL. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...SNOW ADVISORY FOR TONIGHT FOR ZONES INZ003>004-005-012-014. MI...SNOW ADVISORY FOR TONIGHT FOR ZONES MIZ077>079. OH...NONE. && $$ MURPHY/SKIP/T in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 350 PM EST TUE NOV 30 2004 .SHORT TERM... TONIGHT AND WEDNESDAY. BROAD/PERSISTENT 290K ISENT LIFT CONTINUES WITH RAIN WIDESPREAD THROUGH CWA AT ISSUANCE TIME. UPPER LOW ACROSS FAR EASTERN KANSAS EJECTING ENE INTO SOUTHERN GREAT LAKES OVERNIGHT. SURFACE LOW AND INITIAL STRENGTH OF UPPER SYSTEM TENDS TO FAVOR 12Z ETA. WITH GFS TOO FAR EAST WITH SURFACE LOW/WEAKER MORE OPEN MIDLEVEL WAVE. HAVE TRENDED TOWARD AN ETA SOLUTION BUT TEMPERED A BIT AS SOME CONCERN OVER INITIAL WARM NEAR SURFACE TEMPS. WET BULB PROFILE IMPROVES BY 03Z FAR NORTHWEST ZONES AND DEPTH OF ABOVE FREEZING LAYER MAY BE OVERCOME BY DYNAMIC COOLING WITH STRONG UPLIFT WITH 7H LOW DEEPENING OVER 100 METERS/12 HRS WITH TRACK NEAR IN/MI LINE. FAVORABLE DENDRITIC LAYER IN MAX UVM AND GOOD MOISTURE BUT ONLY FOR BRIEF TIME FRAME...GENERALLY AROUND 3HRS AS SYSTEM QUICKLY TRAVERSES CWA. WET SNOWFALL RATES AROUND AN INCH/HOUR POSSIBLE GIVEN STRONG LIFT/DEFORMATION SETUP WITH NORTHWEST CWA BEST AREA TARGETED. WILL GO WITH SNOW ADVISORY OVERNIGHT WITH 3-5 MOST ANTICIPATED...SOME ZONES WITH 2-4 INCHES WITH ADVISORY WITH HAZARD POTENTIAL/IMPACT ENOUGH TO WARRANT A HEADLINE. SYSTEM PULLS OUT EAST RAPIDLY TUESDAY...HAVE GONE A FEW BLO AVNMOS WITH SNOW FOR TUESDAY. && .LONG TERM... WEDNESDAY NIGHT THROUGH TUESDAY...THE FIRST SHORTWAVE WILL BE MOVING OUT OF THE REGION WEDNESDAY AS COLD AIR SPREADS OVER THE AREA BEHIND THIS SYSTEM. HAVE KEPT A CHANCE FOR LAKE EFFECT SNOW SHOWERS IN THURSDAY AFTERNOON AND THURSDAY NIGHT AS FORECAST 850 MB TEMPS DROP TO -10C BY LATE THURSDAY. THIS DOES NOT APPEAR TO BE A VERY FAVORABLE SET UP FOR LAKE EFFECT SNOW AS DELTA T'S ARE MARGINAL AND TRAJECTORIES ARE MORE WESTERLY. ALSO...WINDS SHOULD BACK THURSDAY NIGHT MORE TO THE WEST OR SW WITH INVERSION HEIGHTS DROPPING BELOW 3000 FEET ACCORDING TO GFS BUFKIT...SO HAVE REMOVED THE CHANCE FOR LAKE EFFECT SNOW FRIDAY. HOWEVER...NEXT SHORTWAVE SHOULD MOVE ACROSS THE GREAT LAKES FRIDAY NIGHT...SO HAVE A CHANCE FOR SNOW FRIDAY NIGHT INTO EARLY SATURDAY. GFS LOW LEVEL THICKNESSES BETWEEN 1000 AND 850 MB WELL BELOW 1300M INDICATE SNOW...SO HAVE KEPT THE PCPN ALL SNOW. FOR THE REST OF SATURDAY THROUGH TUESDAY...TEMPERATURES SHOULD WARM ABOVE NORMAL AHEAD OF THE NEXT SYSTEM. GFS AND CANADIAN ENSEMBLES INDICATE A RATHER BROAD TROF OVER THE CENTRAL CONUS EARLY NEXT WEEK WITH SOME TROFS EJECTING EAST...TIMING OF WHICH IS EXTREMELY UNCERTAIN. THEREFORE HAVE A CHANCE FOR RAIN OR SNOW MONDAY INTO TUESDAY WITH TEMPERATURES ABOVE NORMAL. && .AVIATION... MAIN TWEAK TO BUMP UP TIMING OF CHANGEOVER. FAVORING STRONGER ETA/RUC SOLUTION OVER GFS. THIS WOULD SUGGEST DYNAMIC COOLING OF NEAR SURFACE LAYER AFTER 00Z WITH MIX AND SBN AND THEN TO ALL SNOW WITH IFR TO LIFR CONDITIONS 04Z-09Z AND SIMILAR SCENARIO AT KFWA A FEW HOURS LATER. MOISTURE/SYSTEM MOVING QUITE FAST SO TRIED TO KEEP THESE LOWEST CIGS/VSBYS TO A MINIMUM WINDOW. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...SNOW ADVISORY FOR TONIGHT FOR ZONES INZ003>004-005-012-014. MI...SNOW ADVISORY FOR TONIGHT FOR ZONES MIZ077>079. OH...NONE. && $$ MURPHY/SKIP in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1245 PM EST TUE NOV 30 2004 .AVIATION... MAIN TWEAK TO BUMP UP TIMING OF CHANGEOVER. FAVORING STRONGER ETA/RUC SOLUTION OVER GFS. THIS WOULD SUGGEST DYNAMIC COOLING OF NEAR SURFACE LAYER AFTER 00Z WITH MIX AND SBN AND THEN TO ALL SNOW WITH IFR TO LIFR CONDITIONS 04Z-09Z AND SIMILAR SCENARIO AT KFWA A FEW HOURS LATER. MOISTURE/SYSTEM MOVING QUITE FAST SO TRIED TO KEEP THESE LOWEST CIGS/VSBYS TO A MINIMUM WINDOW. && .SHORT TERM... TODAY AND TONIGHT ACTIVE SHORT TERM WITH DRIZZLE AND LIGHT SHOWERS EARLY THIS MORNING IN AREA OF BROAD ISENTROPIC LIFT AND SATURATED LOWER LEVELS. UPPER TROUGH NOW OVER SOUTHWEST CONUS WILL MOVE EAST TODAY AND ALLOW SURFACE LOW PRESSURE TO DEEPEN ACROSS THE NORTHERN GULF COAST STATES. THIS LOW WILL TRACK NORTHEAST AND MODELS HAVE VARIED SOLUTIONS TO EXACT TRACK. THIS HAS IMPORTANT IMPLICATIONS ON OUR FORECAST AS TO WHEN AND WHERE LIQUID PCPN WILL CHANGEOVER TO SNOW TONIGHT. GENERALLY...MEDIUM RANGE MODELS WITH MORE COARSE RESOLUTIONS HAVE A SLIGHTLY WEAKER AND MORE PROGRESSIVE UPPER PATTERN WHICH ALLOWS FOR A WEAKER AND MORE EASTERN SURFACE LOW...BRINGING A LOW THROUGH TENNESSEE INTO SOUTHEAST KY BY THIS EVENING. MODELS WITH IMPROVED LOWER LEVEL RESOLUTION...ETA...RUC20...GEM...UWNMS...ALL WANT TO BRING A SLIGHTLY STRONGER MID AND UPPER LOW ACROSS THE AREA AND THUS HAVE A STRONGER AND MORE WRAPPED UP SURFACE LOW...FARTHER NORTH AND WEST. THESE MODELS TAKE SURFACE LOW ALONG OHIO RIVER AND INTO OHIO. PRESSURE FALLS TONIGHT HAVE BEEN CLOSER TO OHIO RIVER BUT RECENT TRENDS SHOWING A BROAD AREA OF PRESSURE FALLS ACROSS ALL OF SOUTHERN INDIANA AND KENTUCKY. WATER VAPOR NOT ALL THAT IMPRESSIVE WITH CIRCULATION EARLY THIS MORNING IN THE SOUTHWEST CONUS. MUCH UNCERTAINTY REMAINS AND ALL MODELS HAVE SOME MERIT TO THEIR SOLUTIONS. PLAN ON USING A CONSENSUS WHICH WOULD TAKE SURFACE LOW THROUGH NORTHERN KENTUCKY AND BRING DEFORMATION ZONE ACROSS MOST OF OUR NORTHWEST HALF OF THE CWA. DRIZZLE SHOULD BE AROUND MUCH OF THE FORECAST AREA THIS MORNING. AS UPPER LOW LIFTS OUT AND SURFACE LOW MOVES NORTH...RAIN SHOULD BECOME MORE WIDESPREAD TO OUR SOUTH AND MOVE NORTH DURING THE DAY. MODELS ARE A BIT SLOWER AND BEST LIFT DOES NOT MOVE INTO SOUTHERN AREAS TIL MID AFTERNOON AND NORTHERN AREAS LATE THIS AFTERNOON. THERE IS SOME PCPN DEVELOPING AT 08Z ACROSS CENTRAL ILLINOIS IN AREA OF ISENTROPIC LIFT. WILL CONTINUE WITH DEVELOPING RAIN TODAY BUT BEST LIFT AND WIDESPREAD RAIN WILL BE LATER THIS AFTERNOON AND EVENING. TRANSITION TO SNOW TONIGHT DEPENDS ON HOW WELL MODELS ARE HANDLING DYNAMIC COOLING EFFECTS OF STRONG LIFT. SOUNDINGS AND TIME HEIGHT CROSS SECTIONS SUGGEST A CHANGEOVER AROUND 06Z IN WEST AND CLOSER TO 09-12Z FAR EAST. THIS MAY BE A BIT SLOW GIVEN THE STRONG FORCING EXPECTED BETWEEN 03-06Z. WILL TRANSITION TO A RAIN SNOW MIX IN THE WEST AROUND 03Z AND ALL SNOW BY 06Z...WORKING THE CHANGEOVER INTO OHIO BY 10Z OR SO. THIS WILL ALLOW FOR A 1 TO 3 INCH SNOW BAND IN NORTHWEST AND NORTHERN AREA...DOWN TO AN INCH OR LESS SOUTHEAST. THIS IS A GOOD COMPROMISE BETWEEN MODELS AND WILL ALLOW NEXT SHIFT TO ADJUST ACCORDINGLY AS MODELS COME INTO BETTER AGREEMENT AND SURFACE LOW TREND CAN BE BETTER DISTINGUISHED. MOS WAS TOO WARM ON MONDAY GIVEN CLOUDS...PCPN AND EASTERLY FLOW. SIMILAR PATTERN TODAY WITH ONLY SMALL DIURNAL RISES BUT TEMPERATURES STARTING OUT IN THE UPPER 30S. WILL ADJUST GRIDS DOWN JUST A DEGREE OR TWO IN THE NORTH...CLOSER TO COOLER MOS. LOWS TONIGHT IN THE BALLPARK WITH CLOUDS AND PCPN SO FEW CHANGES PLANNED TO MINS. && .LONG TERM... WEDNESDAY THROUGH MONDAY WEDNESDAY...GFS AND ETA DIFFER IN THE DETAILS OF THE UPCOMING SYSTEM IN THE SHORT TERM...BUT BOTH ARE IN GOOD AGREEMENT THAT THE SURFACE LOW AND MID LEVEL FEATURES ALONG WITH ASSOCIATED MOISTURE FIELDS WILL PULL RAPIDLY OUT OF THE CWA WEDNESDAY MORNING. BOTH ETA AND GFS PARTIAL THICKNESS SCHEMES AND H85 TEMPS POINT TOWARDS MAINLY SNOW EVEN AS FAR SOUTHEAST AS KAOH BY 12Z WED. WILL KEEP AN EARLY MORNING LOW CHANCE POP FOR SNOW IN THE OHIO COUNTIES ONLY. BY MIDDAY MODEL SOUNDINGS SHOWING STRONG DRYING AT ALL LEVELS WITH SKIES BECOMING PARTLY CLOUDY. CURRENT CLOUD GRIDS HAVE A GOOD HANDLE ON THIS AND WILL ONLY MAKE A FEW MINOR TWEAKS. WILL LEAN TOWARDS THE COOL SIDE OF GUIDANCE WITH THE POSSIBILITY OF HAVING A LIGHT SNOW COVER IN PLACE BY WED AM ACROSS MUCH OF THE CWA. THURSDAY/FRIDAY...GFS HAS BACKED OFF ON AMOUNT OF TROUGHING TO DEVELOP OVER THE GREAT LAKES THIS PERIOD WITH THE ARCTIC BOUNDARY REMAINING OVER THE FAR NORTHERN LAKES. THUS THE LATEST GFS IS NOT AS COLD AS PREVIOUS RUNS WITH H85 TEMPS AROUND -8C THURS NGT WHICH YIELDS VERY MARGINAL LAKE/850MB DELTA T OF AROUND 16C. EARLY LOOK WOULD POINT TOWARDS W OR WNW FLOW WITH THE DEEPEST AMBIENT SYNOPTIC MOISTURE PROGGED TO BE THURS NGT PERIOD. SEE NO REASON TO CHANGE CONTINUITY AT THIS POINT AND WILL CONTINUE WITH CHANCE POPS IN THE LAKE EFFECT COUNTIES FROM THURS PM THROUGH FRIDAY. GIVEN LACK OF SYNOPTIC SUPPORT AND MARGINAL COLD AIR WOULD NOT ANTICIPATE A SIGNIFICANT LAKE EFFECT EVENT. BY FRIDAY AFTERNOON WAA AND BACKING FLOW SHOULD WEAKEN LAKE EFFECT ACTIVITY AND FORCE ANY REMNANTS NORTH OF THE CWA. FOR THE WEEKEND AM DISCOUNTING THE 00Z/30 GFS RUN WITH ITS VERY STRONG NORTHERN STREAM SHORTWAVE DIGGING SOUTHEAST THROUGH THE GREAT LAKES FRI NGT/SAT. ECMWF AND CANADIAN GEM SUPPORT A MUCH WEAKER AND FURTHER NORTH SOLUTION...KEEPING BEST FORCING AND ANY PRECIP NORTH OF THE CWA. WILL CONTINUE WITH THE DRY FORECAST FOR THE WEEKEND. TEMPS SHOULD BEGIN TO RECOVER TO NEAR OR A LITTLE ABOVE NORMAL OVER THE WEEKEND AS THE SOUTHWEST US TROUGH DEEPENS...ALLOWING A GENERAL RISE OF HEIGHTS OVER THE EASTERN CONUS. SPLIT FLOW WILL CONTINUE THROUGH EARLY NEXT WEEK WITH THE SOUTHWESTERN US TROUGH RELOADING. THE NEXT IN A SERIES OF WAVES WILL EJECT OUT OF THE SOUTHWEST US TROUGH AND SPAWN CYCLOGENESIS OVER THE SOUTHERN PLAINS BY MONDAY. ECMWF/GFS IN VERY GOOD AGREEMENT WITH THIS SYSTEM THROUGH THE END OF DAY 7. WILL RETAIN THE CHANCE FOR RAIN ON MONDAY FOR NOW WITH BROAD WAA PATTERN SETTING UP...BUT AT THIS TIME IT APPEARS THE BETTER CHANCES FOR RAIN WILL BE JUST BEYOND THE END OF THE FORECAST PERIOD. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. && $$ in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1103 PM EST TUE NOV 30 2004 .DISCUSSION... UPDATED IN THE WRN ZONES TO BACK OFF ON COVERAGE OF SHSN AND ACCUMS OVERNIGHT OVER THE KEWEENAW. LATEST ETA AND RUC SNDGS NOT SHOWING AS DEEP OF A COLD LYR MOVING OVER LAKE SUPERIOR AT LEAST INITIALLY. DEPTH OF COLD AIR REACHES TO ONLY 4KFT WITH COLDEST TEMP OF -9C AT TOP OF LYR...POOR FOR DENDRITIC SNOW GROWTH. THUS HAVE CUT BACK FROM NUMEROUS TO SCATTERED ON SHSN COVERAGE WITH LOCAL ACCUMS AROUND A HALF INCH IN GRIDS. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VOSS mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 930 PM EST TUE NOV 30 2004 .UPDATE...TRANSITION FROM RAIN TO SNOW VERY SLOW ACROSS SOUTHEAST LOWER MICHIGAN THIS EVENING. 00Z DTX SOUNDING SHOWS SFC-5K FT WARM LAYER...BUT WARMEST TEMPERATURE IN WARM LAYER ONLY ABOUT 1.5C. BATTLE GOING ON BETWEEN LATENT HEAT RELEASE IN THIS LAYER AND COOLING DUE TO MELTING AT THE TOP OF THIS WARM LAYER. ANTICIPATE AS OMEGA FIELD INCREASES WITH DEEPENING UPPER WAVE...AND HEAVIER PRECIPITATION ASSOCIATED WITH IT...WILL RESULT IN A MORE RAPID EROSION OF THIS WARM LAYER. AS OF 9 PM...RAIN HAD TRANSITIONED TO SNOW IN MOP AND AMN...AND ANTICPATE TRANSISTION TO SNOW IN SAGAINAW VALLEY AROUND MIDNIGHT. SHOULD SEE TRANSITION IN FLINT AND EASTERN THUMB REGION SOMETIME BETWEEN 06-09Z AS STRONGER OMEGA FIELD MOVES ACROSS THE REGION. 01Z RUC CLOSING OFF UPPER LOW JUST SOUTH OF DTW BY 12Z WITH SYSTEM DEEPENING RAPIDLY AND OCCLUDING BETWEEN 06 AND 12Z. THIS LOOKS REASONABLE BASED ON TROP FOLD THAT MOVES ACROSS THE SOUTHERN GREAT LAKES/ NORTHERN OHIO VALLEY OVERNIGHT. LOOKS LIKE TROWAL WILL SET UP JUST EAST OF THE STATE...SO STILL ANTICIPATE CHANGE OVER TO ALL SNOW FOR ENTIRE CWA BY 12Z. WILL NOT MAKE ANY CHANGES TO SNOWFALL TOTALS AT THIS TIME DUE TO UNCERTAIN TRANSITION TIME TO ALL SNOW. ALSO 00Z DTX SOUNDING SHOWING SOME MID LEVEL POTENTIAL INSTABILITY...650-750 MB...AND THIS LAYER OF INSTABILITY EXTENDS BACK INTO THE WESTERN OHIO VALLEY AS NOTED ON ILX SOUNDING. SO WITH SOME CONVECTION ALSO POSSIBLE THIS MAKES SNOWFALL AMOUNTS EVEN MORE DIFFICULT TO PIN POINT. && GSS .PREV DISCUSSION ISSUED AT 410 PM...FORECAST DISCUSSION TO FOCUS ON NEXT 18 HOURS OR SO TRYING TO GET HANDLE ON UPCOMING PRECIPITATION EVENT OVER SOUTHEAST LOWER MICHIGAN. A VERY DYNAMIC SITUATION WHICH MAKES CERTAIN FORECAST PARAMETERS HARD TO PIN DOWN. AS PER PREVIOUS DISCUSSION... GFS MODEL TRENDS HAVE BEEN DEEPER AND FURTHER NORTH AND WEST IN TRACK... BUT STILL SIGNIFICANTLY DIFFERENT THAN THE ETA. THE ETA...ON THE OTHER HAND... HAS BEEN PRETTY CONSISTENT IN LOW TRACK POSITION THE LAST 4-5 MODEL RUNS. AS PER NCEP DISCUSSION... ETA ENSEMBLE MEANS ARE A LITTLE FURTHER EAST THAN THE OPERATIONAL ETA... BUT LATEST RUC IS WAY FURTHER WEST THAN ANY MODEL. ALTHOUGH DEEPENING MAY BE A LITTLE OVERDONE... NEARLY 15 MB IN 12 HOURS... FEEL THE OVERALL TREND AND TRACK OF THE OPERATIONAL ETA IS THE BEST BET. SIGNIFICANT AMOUNT OF LIFT IS PRESENT IN THE MODEL SOLUTION RESULTING LARGELY FROM TREMENDOUS DECELERATION IN THE EXIT REGION OF THE H3 JET (30-50 KNOTS FROM OH VALLEY TO GREAT LAKES)... EXCELLENT LOWER TO MID TROPOSPHERIC FRONTOGENESIS ALONG THE BAROCLINIC ZONE... AND WEAK STATIC STABILITY WITHIN THE CLOUD LAYER. IN FACT...ETA CROSS-SECTIONS SHOW BEST OMEGA ARB TO MBS OVERNIGHT IN A VERTICAL THETA WEAKNESS AND CENTERED ON THE -15C ISOTHERM. MOISTURE-WISE... ALTHOUGH THERE ARE CONCERNS ABOUT LARGE PRECIPITATION AMOUNTS IN THE WARM SECTOR AHEAD OF THE LOW PREVENTING THE BEST MOISTURE FROM WRAPPING DEEPLY INTO THE TROWAL... BELIEVE MODEL QPFS ON THE NORTH SIDE OF THE LOW ARE GENERALLY IN THE BALLPARK. THE BIG QUESTION IS THE DEGREE OF COLD AIR AVAILABLE FOR CHANGING AND KEEPING PRECIPITATION AS SNOW OVERNIGHT. BASED ON CURRENT TRENDS... WE'RE GOING TO HAVE TO DEPEND ALMOST TOTALLY ON DYNAMIC COOLING OF THE COLUMN TO GET AN EARLY ENOUGH CHANGEOVER FOR HEAVY SNOW. SOME LOW AND MID LEVEL DRY AIR IS PRESENT OVER NORTHERN LOWER... BUT EVAPORATIVE COOLING LIKELY TO ONLY PLAY A BIGGER ROLE ON THE NORTHERN FRINGE... AND AWAY FROM THE BETTER MOISTURE. MODEL CRITICAL THICKNESS VALUES STILL WAY HIGHER THAN WE WOULD LIKE TO SEE... AND ARCTIC FRONT NORTH OF LAKE SUPERIOR IS PRETTY MUCH OUT OF PLAY... BUT 925MB AND 850MB TEMPS GIVE SOME CONFIDENCE TO A TIMELY CHANGEOVER NORTH OF M59/I69 CORRIDORS TOWARD MIDNIGHT... AND FURTHER SOUTH LATER IN THE NIGHT. GIVEN ALL THAT... THINK A HIGH END ADVISORY IS STILL GOOD UNTIL PRECIPITATION TYPE TRENDS GIVE US A REASON TO CHANGE. WILL EXPAND THE ADVISORY INTO MIDLAND... BUT WILL OTHERWISE LET IT RIDE. .DTX WATCHES/WARNINGS/ADVISORIES...SNOW ADVISORY LATE TONIGHT FOR BAY...SAGINAW...HURON...TUSCOLA..SHIAWASSEE...GENESEE...LAPEER...SANI LAC...LIVINGSTON...MIDLAND COUNTIES. GALE WARNING LAKE ST CLAIR AND MICHIGAN WATERS OF LAKE ERIE WEDNESDAY && $$ EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 815 PM EST TUE NOV 30 2004 .DISCUSSION...SFC MAP AT 00Z SHOWS SFC LOW OVER SRN INDIANA WITH A WARM FRONT THROUGH SRN KY TO EC TN. INVERTED TROUGH AXIS EXTENDED NORTH OF THIS LOW INTO NR IN/NW OH. TO OUR NORTH...ANOTHER AREA OF ELONGATED LOW PRESSURE STRETCHED ACROSS LAKE SUPERIOR AND NRN MN TO ND. SAT SHOWED FEW CLOUDS ACROSS THE UP...BUT INCREASING AND THICKENING CLOUDS MOVING NORTHWARD AHEAD OF SFC IN INDY. SFC TEMPS WERE IN THE LOWER 30S SOUTH TO MIDDLE 20S IN EASTERN UPPER. RADARS AROUND THE REGION SHOWING MAIN PRECIP SHIELD WORKING INTO BIG RAPIDS AND MT PLEASANT WITH THE NRN FRINGE AS RAIN/SNOW. THE BETTER SNOWS WERE FALLING BACK TO OUR WEST OVER NRN IL...WHERE ENHANCEMENTS SEEN ON SATELLITE UNDER THE UPPER LOW HAVE ALLOWED THE PRECIP TO CHANGE OVER TO SNOW AND SNOW INTENSITIES WERE ON THE ORDER OF 1"/HR. CONCERNS FOR THE REMAINDER OF THE NIGHT...EVOLUTION OF PRECIPITATION...TYPE/AMOUNTS AND LOCATION. SFC LOW WILL SLIDE INTO WESTERN LAKE ERIE BY 09Z WITH THE MID LEVEL LOW AND COLDER AIR ALOFT WORKING INTO SE LOWER. AREA OF DEFORMATION WORKS IN OVER THE SE CWA...NEARER THE THUMB REGION TONIGHT WITH THE BEST -DIVQ/MID LEVEL LAPSE RATES FROM THE THUMB SOUTHWARD INTO THE DTX AREA. THIS ALSO WHERE UPDATED RUC SOUNDINGS ARE SUGGESTING ICE CRYSTAL PRODUCTION WILL BE IN A FAVORED ZONE BETWEEN -12C/-18C THUS BETTER PRECIP INTENSITIES WILL RESIDE OVERNIGHT. THIS TEMP REGIME IS ALSO SEEN HAPPENING OVER NRN IL ATTM. OVERALL...DO NOT EXPECT ANYTHING DRASTICALLY DIFFERENT FROM EARLIER FORECAST. ONE CHANGE WILL BE THAT LATEST MODEL RUNS...WHICH IS SEEMINGLY A GOOD IDEA PER LATEST OBSERVATIONAL DATA...SUGGEST ANOTHER HOUR OR TWO OF ISENTROPIC LIFT...AGAIN MAINLY ACROSS THE SE CWA GENERALLY BETWEEN 02Z AND 09Z. 00Z APX SOUNDING STILL SHOWING ENOUGH DRY LAYERS THAT NEED TO BE SATURATED BEFORE WE START SEEING PRECIP...BUT IT IS KNOCKING AT THE DOOR ACROSS THE SE CWA ATTM. THE DRIEST OF AIR IS STRETCHED ACROSS THE NW CWA...AND WILL BE FOR THE REMAINDER OF THE NIGHT. OVERALL...WILL GO WITH 2-4 INCHES ACROSS THE FAR SE CWA...TAPERING OFF TO AROUND AN INCH FROM CADILLAC TO GRAYLING...OSCODA AND FAR SOUTHERN ALPENA COUNTIES. NO SNOW ACCUMULATION EXPECTED GENERALLY ALONG AND NORTH OF A LINE FROM SUTTONS BAY TO PETOSKEY AND CHEBOYGAN. SNOW AMOUNTS HAVE ALSO BEEN TAPERED DOWN ALONG THE IMMEDIATE LAKESHORE ACROSS THE SRN CWA...WHERE SUBTLE TEMPERATURE MODIFICATION/WARMING CAN CREATE A MIX WITH RAIN AS THE WARM LAYER ABOVE THE SFC WILL BE TEETERING AROUND 1200 FEET OR SO. WITH H8 TEMPS HOLDING IN THE -2 TO -4 RANGE...SEE NO LAKE EFFECT OR LAKE ENHANCEMENTS FOR THE NIGHT. WINDS MAY GET UP TO 20 KTS OR SO ACROSS THE LAKE MICHIGAN SHORE NEAR MANISTEE LATE TONIGHT...BUT NO MARINE HEADLINES EXPECTED EITHER. SMD && .PREV DISCUSSION ISSUED AT 345 PM EST TUE NOV 30 2004 WEDNESDAY...A DAY OF TRANSITION FROM SYSTEM SNOW IN THE SE TO LAKE EFFECT/ENHANCED SNOW IN THE NORTH AND WEST. COLD AIR BEGINS TO SLIDE INTO THE REGION DURING THE MORNING...WITH 850 MB TEMPS DROPPING FROM -5 C AT 12Z TO -8/-9C IN THE AFTERNOON. OVER LAKE INSTABILITY WILL BE SUFFICIENT FOR LAKE ENHANCEMENT...BUT LOW LEVEL MOISTURE WILL BE MODEST AT BEST. MOISTURE WILL EXTEND ABOVE THE -10 C ISOTHERM...BUT WILL BE AROUND 50 PCT ABOVE 850 MB. DEEPER MOISTURE WILL RESIDE ACROSS ERN UPR MICHIGAN...WHERE BETTER CHANCES AND SLIGHTLY HIGHER SNOW AMOUNTS ARE EXPECT. STILL...EXPECT LESS THAN AN INCH OF SNOWFALL ACROSS THE SNOWBELT REGIONS THRU THE DAY UNTIL DEEPER MOISTURE ARRIVES LATER WEDNESDAY NIGHT AND THURSDAY. ACTIVE WEATHER PATTERN WEDNESDAY NIGHT THROUGH EARLY NEXT WEEK WITH SPLIT FLOW REGIME ACROSS THE LOWER 48...WITH NUMEROUS SHORTWAVE TROFS IN NORTHERN STREAM MOVING ACROSS THE LAKES. THIS WILL RESULT IN SEVERAL LAKE ENHANCED/LAKE EFFECT SNOW EVENTS. WEDNESDAY NIGHT...MODELS BEGINNING TO COME INTO AGREEMENT ON THE DETAILS...WITH COLD AIR WRAPPING INTO THE AREA BEHIND SURFACE LOW. ALTHOUGH PERSISTENT W/NW FLOW AND DELTA T/S DROPPING TOWARD 15 C...MOISTURE IS SHALLOW /MAINLY BENEATH 900MB/ AND MID LEVEL FORCING IS ABSENT. BECAUSE OF THIS...BELIEVE WE WILL SEE ONLY VERY LIGHT LAKE EFFECT SNOW SHOWERS OR FLURRIES. THURSDAY AND THURSDAY NIGHT...THINGS BECOME MORE INTERESTING ON THURSDAY...AS POTENT SHORTWAVE TROF DROPS OUT OF SOUTHERN CANADA AND SWINGS ACROSS THE NORTHERN LAKES. MID LEVEL FORCING INCREASES RAPIDLY THURSDAY MORNING...WITH MORE FAVORABLE H7-H5 Q VECTOR CONVERGENCE AND H7 OMEGA FIELDS. DELTA T/S WILL BE BETWEEN 14-16 DEGC...WITH MUCH DEEPER MOISTURE FROM THE SURFACE THROUGH H5. THIS SHOULD ALL LAY THE GROUNDWORK FOR A SEVERAL HOUR WINDOW OF LAKE ENHANCED SNOW ON THURSDAY...DIMINISHING LATER IN THE DAY AS THE BANDS BECOME DISRUPTED BY VEERING LOW LEVEL WIND FIELDS. I WILL GO WITH LIKELY TO CATEGORICAL POPS ACROSS WEST FLOW AREAS...WITH SNOW ACCUM OF 1-3 INCHES. WOULD NOT BE SURPRISED TO SEE ADVISORY TYPE SNOW ACCUM ACROSS PARTS OF THE AREA ON THURSDAY /DEPENDING ON HOW COLD H8 TEMPS ARE AND WHAT CONTRIBUTION THE LAKES PROVIDE TO THE EVENT/. LOW LEVEL FLOW BECOMES MORE NORTHWEST LATE THURSDAY AFTERNOON AND EVENING AS SHORTWAVE TROF PULLS EAST OF THE AREA. MOISTURE DEPTH DECREASES AND INVERSIONS LOWER...SO LAKE EFFECT/ENHANCED ACTIVITY SHOULD GRADUALLY DIMINISH. FRIDAY AND FRIDAY NIGHT...FAST NORTHERN STREAM FLOW CONTINUES ON FRIDAY AS NEXT CLIPPER TYPE SYSTEM MOVES OUT OF THE UPPER MIDWEST AND INTO THE LAKES. H8 TEMPERATURES WARMING TO -4 TO -6 DEGC...SO MINIMAL LAKE COMPONENT TO THE SNOW. LIGHT SNOW WILL OVERSPREAD MUCH OF THE AREA FROM WEST-EAST FRIDAY AFTERNOON AND CONTINUE INTO AT LEAST THE FIRST PART OF FRIDAY NIGHT. LONGWAVE PATTERN BEGINS TO CHANGE OVER THE WEEKEND...WITH LONGWAVE TROF DIGGING OVER THE WRN STATES AND UPPER FLOW BACKING SOUTH/SOUTHWEST ACROSS THE GREAT LAKES. WARM FRONT MOVES NORTH THROUGH MICHIGAN SATURDAY NIGHT AND SUNDAY. I WILL PUT LOW POPS ACROSS ENTIRE AREA SATURDAY NIGHT AND OVER NORTHERN AREAS ON SUNDAY. STRONGER SURFACE LOW WILL EJECT OUT OF WESTERN TROF AND MOVE TOWARD THE GREAT LAKES EARLY NEXT WEEK. MODEL DIFFERENCES ON HOW STRONG OR FAR WEST SYSTEM WILL TRACK...WHICH WILL IMPACT PCPN TYPE. FOR NOW...I WILL GO WITH CHANCE POPS AND A CHANCE OF RAIN/SNOW. && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JK/EME mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND RAPIDS MI 420 PM EST TUE NOV 30 2004 .SHORT TERM... THE GFS HAS FINALLY COME MORE IN LINE WITH THE FARTHER NORTH AND WEST TRACK OF THE ETA. THUS CONFIDENCE HAS INCREASED THAT A BAND OF ACCUMULATING WET SNOW IS GOING TO DEVELOP THIS EVENING ACROSS PARTS OF CENTRAL AND SOUTHERN LOWER MICHIGAN. THE BIG COMPLICATING FACTOR WITH THIS SYSTEM IS THAT IT IS LIFTING NORTH FROM THE GULF AND CURRENTLY HAS PRIMARILY RAIN WITH IT. SURFACE TEMPS ARE CURRENTLY IN THE UPPER 30S...SO THIS EVENT WILL START OUT AS PRIMARILY RAIN BEFORE CHANGING OVER LATER THIS EVENING. JUST WHEN THAT CHANGEOVER OCCURS WILL BE VERY CRITICAL FOR HOW MUCH SNOW ACCUMULATION WE END UP WITH. AM VERY CONCERNED THAT THE AREA FROM HOLLAND TO GRAND RAPIDS TO ALMA WILL APPROACH OR SLIGHTLY EXCEED WARNING CRITERIA SNOWFALL. THE LAPS SOUNDINGS NEAR GRR SHOW THE MELTING LAYER IS AT ABOUT 2500 FEET AND ENTIRELY ABOVE FREEZING ABOVE THAT. THE WET BULB ZERO IS QUITE LOW AT ONLY 1500 FT. FEEL THAT ONCE HEAVIER PCPN DEVELOPS... IT WON'T TAKE VERY LONG FOR THE PCPN TO GO TO PRIMARILY ALL SNOW. THE RUC FCST SOUNDINGS SUPPORT GOOD DENDRITIC GROWTH UP HIGH AND GOOD AGGREGATION DOWN LOW... WITH THE STRONGEST OMEGA COINCIDENT WITH THE MAX SNOW GROWTH REGION UP HIGH. WOULD EXPECT 6 HOURS OF FAIRLY HEAVY SNOW FROM 03Z TO 09Z IN THE HOLLAND AND GRAND RAPIDS AREAS. WILL KEEP THE ADVISORY FOR NOW... BUT AM VERY MUCH ON THE FENCE FOR A WARNING IN THIS AREA. MEANWHILE THE FCST SOUNDINGS OVER THE SRN PORTION OF THE CWFA SUPPORT PRIMARILY ALL RAIN THIS EVENING... SO HAVE DELAYED THE ADVISORY UNTIL 11 PM. IT'S ALSO A BIT CONCERNING THAT THE SURFACE LOW CONTINUES LIFTING ALMOST DUE NORTH... AND THE NEWER RUNS OF THE RUC MODEL ARE SHOWING AN EVEN FARTHER WEST TRACK THAN THE 12Z ETA. THIS WILL MAKE IT VERY DIFFICULT FOR THE JACKSON AREA TO GET ADVISORY CRITERIA SNOWFALL SINCE THE CHANGEOVER WILL NOT OCCUR UNTIL AFTER MIDNIGHT. WILL KEEP THEM IN IT FOR NOW. STORM IS QUICK TO EXIT THE REGION EARLY WEDNESDAY MORNING... AND RAPID DRYING/SUBSIDENCE BEHIND IT SHOULD LEAD TO DRY CONDITIONS WITH PARTLY OR EVEN MOSTLY SUNNY CONDITIONS. THE NORTHERN STREAM EVENTUALLY BECOMES MORE DOMINATE ACROSS THE GREAT LAKES REGION LATER THIS WEEK... WITH FAST MOVING CLIPPER IMPULSES BRINGING THE POTENTIAL FOR SOME LAKE EFFECT/ENHANCED SNOW. RIGHT NOW THE BEST TIME FOR BETTER L.E.S APPEARS TO BE ON THURSDAY AND THURSDAY NIGHT. .LONG TERM... THE EXTENDED PERIOD WILL REMAIN ACTIVE. NORTHWEST FLOW WILL BRING ANOTHER SHORT WAVE ACROSS THE REGION LATE FRIDAY NIGHT/SATURDAY. THE GFS IS A BIT STRONGER WITH THIS FEATURE THAN THE GEM...BUT THE TIMING IS SIMILAR. WILL KEEP RAIN AND SNOW CHCS GOING. ATTENTION THEN TURNS TO A SHORT WAVE IN THE SOUTHERN STREAM. THIS SYSTEM TRACKS NE OVER MI BY MONDAY AND SHOULD DRAW UP SLIGHTLY WARMER AIR. BELIEVE THIS WILL RESULT IN MOSTLY RAIN IN THE SOUTH AND ALONG THE LAKE...WITH MIXED PCPN IN THE INTERIOR NORTH. YET ANOTHER SHORT WAVE MAY APPROACH THE WESTERN GREAT LAKES BY TUESDAY. HIGHS MOSTLY AROUND 40 AND LOWS AROUND 30 THROUGH THE PERIOD. && .GRR WATCHES/WARNINGS/ADVISORIES...SNOW ADVISORY TONIGHT 6PM UNTIL 6AM... MUSKEGON... NEWAYGO... MECOSTA... ISABELLA...OTTAWA... KENT... MONTCALM... GRATIOT... IONIA... CLINTON...ALLEGAN... BARRY... SNOW ADVISORY LATER TONIGHT... 11 PM UNTIL 6 AM... EATON... INGHAM... VAN BUREN... KALAMAZOO...CALHOUN... AND JACKSON. $$ MEADE JK mi AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 410 PM EST TUE NOV 30 2004 .DISCUSSION...FORECAST DISCUSSION TO FOCUS ON NEXT 18 HOURS OR SO TRYING TO GET HANDLE ON UPCOMING PRECIPITATION EVENT OVER SOUTHEAST LOWER MICHIGAN. A VERY DYNAMIC SITUATION WHICH MAKES CERTAIN FORECAST PARAMETERS HARD TO PIN DOWN. AS PER PREVIOUS DISCUSSION... GFS MODEL TRENDS HAVE BEEN DEEPER AND FURTHER NORTH AND WEST IN TRACK... BUT STILL SIGNIFICANTLY DIFFERENT THAN THE ETA. THE ETA...ON THE OTHER HAND... HAS BEEN PRETTY CONSISTENT IN LOW TRACK POSITION THE LAST 4-5 MODEL RUNS. AS PER NCEP DISCUSSION... ETA ENSEMBLE MEANS ARE A LITTLE FURTHER EAST THAN THE OPERATIONAL ETA... BUT LATEST RUC IS WAY FURTHER WEST THAN ANY MODEL. ALTHOUGH DEEPENING MAY BE A LITTLE OVERDONE... NEARLY 15 MB IN 12 HOURS... FEEL THE OVERALL TREND AND TRACK OF THE OPERATIONAL ETA IS THE BEST BET. SIGNIFICANT AMOUNT OF LIFT IS PRESENT IN THE MODEL SOLUTION RESULTING LARGELY FROM TREMENDOUS DECELERATION IN THE EXIT REGION OF THE H3 JET (30-50 KNOTS FROM OH VALLEY TO GREAT LAKES)... EXCELLENT LOWER TO MID TROPOSPHERIC FRONTOGENESIS ALONG THE BAROCLINIC ZONE... AND WEAK STATIC STABILITY WITHIN THE CLOUD LAYER. IN FACT...ETA CROSS-SECTIONS SHOW BEST OMEGA ARB TO MBS OVERNIGHT IN A VERTICAL THETA WEAKNESS AND CENTERED ON THE -15C ISOTHERM. MOISTURE-WISE... ALTHOUGH THERE ARE CONCERNS ABOUT LARGE PRECIPITATION AMOUNTS IN THE WARM SECTOR AHEAD OF THE LOW PREVENTING THE BEST MOISTURE FROM WRAPPING DEEPLY INTO THE TROWAL... BELIEVE MODEL QPFS ON THE NORTH SIDE OF THE LOW ARE GENERALLY IN THE BALLPARK. THE BIG QUESTION IS THE DEGREE OF COLD AIR AVAILABLE FOR CHANGING AND KEEPING PRECIPITATION AS SNOW OVERNIGHT. BASED ON CURRENT TRENDS... WE'RE GOING TO HAVE TO DEPEND ALMOST TOTALLY ON DYNAMIC COOLING OF THE COLUMN TO GET AN EARLY ENOUGH CHANGEOVER FOR HEAVY SNOW. SOME LOW AND MID LEVEL DRY AIR IS PRESENT OVER NORTHERN LOWER... BUT EVAPORATIVE COOLING LIKELY TO ONLY PLAY A BIGGER ROLE ON THE NORTHERN FRINGE... AND AWAY FROM THE BETTER MOISTURE. MODEL CRITICAL THICKNESS VALUES STILL WAY HIGHER THAN WE WOULD LIKE TO SEE... AND ARCTIC FRONT NORTH OF LAKE SUPERIOR IS PRETTY MUCH OUT OF PLAY... BUT 925MB AND 850MB TEMPS GIVE SOME CONFIDENCE TO A TIMELY CHANGEOVER NORTH OF M59/I69 CORRIDORS TOWARD MIDNIGHT... AND FURTHER SOUTH LATER IN THE NIGHT. GIVEN ALL THAT... THINK A HIGH END ADVISORY IS STILL GOOD UNTIL PRECIPITATION TYPE TRENDS GIVE US A REASON TO CHANGE. WILL EXPAND THE ADVISORY INTO MIDLAND... BUT WILL OTHERWISE LET IT RIDE. .DTX WATCHES/WARNINGS/ADVISORIES...SNOW ADVISORY LATE TONIGHT FOR BAY...SAGINAW...HURON...TUSCOLA..SHIAWASSEE...GENESEE...LAPEER...SANI LAC...LIVINGSTON...MIDLAND COUNTIES. GALE WARNING LAKE ST CLAIR AND MICHIGAN WATERS OF LAKE ERIE WEDNESDAY && $$ EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 410 PM EST TUE NOV 30 2004 .DISCUSSION... MAIN FCST ISSUE OVER THE NEXT FEW DAYS WILL LES. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW SPLIT FLOW CONTINUING. IN THE SRN BRANCH...ONE SHORTWAVE WAS HEADING FROM THE SRN PLAINS TOWARD OHIO VALLEY/SRN LAKES WHILE ANOTHER SHORTWAVE WAS DROPPING TOWARD THE SRN ROCKIES...BUT NEITHER OF THESE WAVES WILL BE AFFECTING THE WEATHER HERE. INSTEAD...OUR ATTENTION WILL BE ON A SERIES OF NRN STREAM SHORTWAVES. THE FIRST IS DROPPING THRU SASKATCHEWAN TOWARD MANITOBA NOW WITH THE NEXT ONE OVER THE YUKON. AT THE SFC...ARCTIC FRONT EXTENDS FROM ND/MANTIOBA BORDER TO JUST N OF LAKE SUPERIOR AND TO S OF JAMES BAY. TEMPS AT 20Z WERE STILL AT OR BELOW ZERO AT CYPL AND POINTS N AND W WHILE IT WAS A BALMY 36 AHEAD OF THE FRONT AT CYQT. SOME -SN AND FLURRIES WERE OCCURING ALONG AND JUST BEHIND FRONT. OVER THE NEXT FEW DAYS...PCPN FCST WILL REVOLVE AROUND MOVEMENT OF THIS COLD FRONT AS A SERIES OF SHORTWAVES PASS THRU THE REGION. ETA/GFS ARE IN GOOD AGREEMENT SHOWING COLD FRONT DRIFTING S OVER LAKE SUPERIOR TONIGHT...REACHING THE KEWEENAW BY 12Z AND THEN DROPPING INTO THE REST OF UPPER MI WED AS FIRST SHORTWAVE PASSES ACROSS ONTARIO. WEAK LOW TO MIDLEVEL QVECTOR CONVERGENCE IS PROGGED WITH SHORTWAVE AT THE TIME COLD FRONT IS DRIFTING OVER THE KEWEENAW. WOULD EXPECT FAIRLY SHARP LOW-LEVEL CONVERGENCE COMBINED WITH WEAK SYNOPTIC FORCING TO RESULT IN DECENT -SHSN DEVELOPMENT ALONG/NEAR COLD FRONT LATE TONIGHT. PRESENCE OF LOW CEILINGS BLO 2KFT AND -SN ALONG FRONT NOW INDICATES PLENTY OF LOW-LEVEL MOISTURE WILL BE AVBL PRIOR TO ADDITION OF HEAT/MOISTURE FLUXES FROM LAKE. WILL THUS BUMP UP POPS TO LIKELY OVER THE KEWEENAW WELL AFTER MIDNIGHT. DESPITE OVERALL FAVORABLE CONDITIONS...BEST SNOW GROWTH TEMPS ARE LOCATED ABOVE BETTER LOW-LEVEL MOISTURE WHICH SHOULD WORK TO LIMIT ACCUMULATION POTENTIAL. WHEN ALSO CONSIDERING A LATE START...WILL ONLY INCLUDE A MENTION OF AN INCH MAYBE 2 FOR TONIGHT. WILL PUSH -SHSN OR FLURRIES S TO ONTONAGON/BARAGA COUNTIES VERY LATE IN THE NIGHT. ELSEWHERE...EXPECT A DRY NIGHT WITH SOME INCREASE IN CLOUDS. -SHSN/FLURRIES WILL ACCOMPANY FRONT S ON WED...MAINLY NEAR THE LAKE. LOW-LEVEL CONVERGENCE SETS UP BEST FROM THE KEWEENAW TO AROUND BIG BAY AND OVER TO MUNISING/PICTURED ROCKS WHILE LAKE-850MB DELTA-T INCREASES TO 16-19C. CONDITIONS LOOK FAVORABLE FOR ACCUMULATIONS ESPECIALLY EARLY ON AS COLD FRONT/SHARP CONVERGENCE MOVE S AND ONSHORE OVER AREAS S AND E OF THE KEWEENAW. HOWEVER...BEST SNOW GROWTH TEMPS STILL REMAIN DISPLACED A BIT ABOVE BEST LOW-LEVEL MOISTURE AND UPWARD MOTION. THIS INDICATED MORE SO BY ETA THAN GFS. TOUGH TO SAY WHICH MODEL HAS BEST HANDLE ON THAT AS BOTH LOOK REASONABLY WELL INITIALIZED UPSTREAM. FOR NOW WILL GO WITH ACCUMULATIONS OF 1 TO LOCALLY 3 INCHES FROM ONTONAGON COUNTY TO KEWEENAW AND 1-4 EAST OF MARQUETTE SINCE FRONT/SHARP CONVERGENCE WILL BE COMING ONSHORE THERE WED MORNING. LES WILL THEN CONTINUE INTO WED NIGHT UNDER FAIRLY LIGHT NWRLY LOW-LEVEL FLOW WITH DELTA-T 17-20C AND INVERSION AROUND 5KFT PER GFS. WITHOUT ANY ENHANCING MECHANISMS HAVE MAINTAINED PREV FCST OF 1-3 INCHES FOR NOW. ATTENTION THEN TURNS TO NEXT SHORTWAVE DROPPING SE INTO THE GREAT LAKES THU. THIS COULD BE AN INTERESTING SITUATION AS DEEP LAYER FORCING OVERSPREADS ALREADY UNSTABLE CONDITIONS OVER THE LAKE (DELTA-T AROUND 16C OR SO). PREFER GFS WHICH SHOWS A BETTER SFC REFLECTION AS SHORTWAVE PASSES OVER THE AREA. THE ETA BARELY SHOWS ANY AFFECT ON SFC WIND FIELD AS SHORTWAVE PASSES (18Z ETA HAS COME AROUND TO GFS TYPE SOLUTION THOUGH NOW). CANADIAN GLOBAL AND UKMET ALSO LEND SUPPORT FOR GFS. DON'T NECESSARILY BUY THE GFS WIND FIELD...BUT WOULD EXPECT TO SEE SOME SORT OF SFC CIRCULATION DEVELOP OR AT LEAST SHARP SFC TROFFING OVER THE LAKE AS SYNOPTIC FORCING OVERSPREADS INSTABILITY...ESPECIALLY SINCE LOW-LEVEL WIND FIELD IS RELATIVELY LIGHT PRIOR TO ARRIVAL OF SHORTWAVE. GIVEN INSTABILITY...FORCING AND DEEP MOISTURE...POTENTIAL IS THERE FOR LOCALLY HEAVY LES (HEADLINE EVENT)...BUT AT THIS POINT...BEING MORE THAN 48HRS INTO MODEL RUN...IT'S HARD TO SAY HOW THE ALL IMPORTANT WIND FIELDS WILL RESPOND AND WHERE HEAVIEST LES WILL OCCUR. DO EXPECT MOST AREAS NEAR THE LAKE TO SEE SOME DECENT SNOW AT SOME POINT AS WIND SHIFTS TO THE NW OR N AND WILL HIGHLIGHT POTENTIAL IN THE HAZARDOUS WEATHER OUTLOOK. NEXT SHORTWAVE ARRIVES LATE FRI. BACKING WINDS/WAA AHEAD OF FEATURE WILL GRADUALLY BRING AN END TO LES FROM W TO E BY FRI MORNING. THEN EXPECT SOME SYNOPTIC -SN WITH WAVE FRI AFTN/EVENING. MOST AREAS MAY SEE AN INCH OR SO FROM THAT. SAT-TUE...AFTER A FEW DAYS DAYS OF NRN STREAM CLIPPER TYPE SHORTWAVES...PATTERN EVOLUTION OVER THE WEEKEND INTO EARLY NEXT WEEK TO ONE OF AMPLIFIED SRN STREAM TROFFING OVER THE WRN STATES (COMMON FEATURE OF RECENT WEEKS) BRINGS THE POTENTIAL FOR SRN STREAM ENERGY TO TRACK INTO THE GREAT LAKES. HAVE DISCOUNTED 00Z/12Z UKMET TODAY AS IT IS THE ONLY MODEL TO BRING A SIGNIFICANT ARCTIC AIRMASS INTO THE GREAT LAKES SAT/SUN. THIS IS NOT SUPPORTED BY ECMWF/CANADIAN/GFS OR GFS ENSEMBLES. RATHER...CONSENSUS IS FOR LAST IN THE SERIES OF NRN STREAM WAVES TO PUSH A COLD FRONT INTO THE AREA SAT WITH BULK OF COLD AIR SLIDING OFF TO THE E WELL TO THE N. IN RESPONSE TO DEVELOPING WRN TROF...WAA REGIME IS ALREADY BEGINNING TO TAKE SHAPE SUN THOUGH THERE IS SOME DISAGREEMENT ON HOW FAST THIS WILL OCCUR. ECMWF BRINGS SFC HIGH PRES RIDGE ACROSS THE AREA SUN...DELAYING RETURN FLOW UNTIL SUN NIGHT/MON. CANADIAN/GFS AND GFS ENSEMBLES SUPPORT A FASTER RETURN OF WAA AND WILL FOLLOW THIS SOLUTION. NOT SO CERTAIN PCPN WILL BREAK OUT ALREADY ON SUN...BUT SINCE GOING FCST HAS IT...AND CANADIAN AND GFS ALSO SUGGEST IT...WILL MAINTAIN LOW CHC POPS SUN. DEEP SW FLOW AND ONE OR MORE SHORTWAVES WILL AFFECT THE GREAT LAKES MON/TUE WITH GROWING INDICATIONS THAT ONE MAY SPIN UP A DECENT SFC LOW THAT WILL TRACK INTO THE GREAT LAKES ON TUE. PLENTY OF UNCERTAINTY HERE OBVIOUSLY...BUT ECMWF/GFS AND GFS ENSEMBLES DO SUPPORT THAT IDEA. PTYPE WILL BECOME AN ISSUE AS PERSISTENT WAA ERODES COLD AIRMASS. AT THIS POINT...RAIN OR SNOW WORDING WILL BE UTILIZED MON/TUE WITH HIGHER POPS (STILL CHC THOUGH) ON TUE. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON mi AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1150 AM EST TUE NOV 30 2004 .UPDATE... FOLLOWING COORDINATION WITH GRR HAVE OPTED TO ISSUE A SNOW ADVISORY FROM ROUGHLY THE NORTHERN HALF OF THE FORECAST AREA FOR TONIGHT. LATEST ETA AND NGM HAVE FALLEN IN LINE WITH PREVIOUS RUNS... AND ETA SURFACE LOW TRACK HAS ACTUALLY BEEN PRETTY CONSISTENT THE LAST 4-5 RUNS IN RAPIDLY DEEPENING THE LOW AS IT MOVES INTO NORTHERN OHIO AND THE NGM HAS PRETTY MUCH FALLEN IN LINE WITH THAT. GOT A QUICK VIEW OF THE 12 UTC GFS WHICH CONTINUES TO TREND TOWARD A SOLUTION SLIGHTLY DEEPER AND FURTHER NORTH AND WEST. ITS STILL WELL SOUTH OF THE OTHER MODELS BUT AT LEAST IS NOW TRENDING IN THEIR DIRECTION. PLENTY OF MIOISTURE ASSOCIATED WITH THIS SYSTEM WITH IT ORIGINS IN THE GULF... BUT PRECIPITATION TYPE AND SPEED OF THE SYSTEM ARE STILL DIFFICULT TO GET A HANDLE ON. CRITICAL 1000-850 MB THICKNESS VALUES ARE STILL A LITTLE ON THE HIGH SIDE OVER MOST OF THE AREA... BUT SURFACE TEMPS ARE LINGERING IN THE MID 30S OVER THE NORTHERN CWA WITH A TOUCH OF DRY AIR STILL SEEMINGLY READY TO IMPINGE ON THE NOERTHERN EDGE OF THE SYSTEM. ALL IN ALL FELT THE LATEST TRENDS WERE ENOUGH TO HOIST THE ADVISORY EARLY... WITH THE LACK OF A LESS-THAN-CLASSIC DEFORMATION AXIS AND THE ACCELERATING SYSTEM LIMITING AMOUNTS JUST BELOW WARNING CRITERIA. $$ .PREVIOUS DISCUSSION ISSUED AT 423 AM EST... .SHORT TERM... PERSISTENT STRATUS DECK ACROSS MUCH OF SOUTHERN LOWER MICHIGAN IS SHOWING SIGNS OF INCREASING IN DEPTH...AS PER LATEST 11-3.9 GOES IMAGERY. ANTICIPATE LITTLE IN THE WAY OF CHANGE WITH CLOUD COVER TODAY AS THE LOWER AND MID LEVEL MOISTURE CONTENT INCREASES FROM THE SOUTH IN ADVANCE OF THE DEVELOPING SYSTEM ACROSS THE LOWER MISSISSIPPI VALLEY REGION. THE OVERCAST WILL HELP KEEP THE DIURNAL TEMPERATURE RISE IN CHECK TODAY...EXPECT THAT HIGHS WILL BE SIMILAR TO YESTERDAY/S VALUES. LEADING WAVE OF WARM ADVECTION IN ADVANCE OF THE NEXT SYSTEM IS POISED ACROSS CENTRAL ILLINOIS AND INDIANA AND IS KICKING OFF A BAND OF SHOWERS. LATEST GUIDANCE CONTINUES TO POINT TOWARD THAT PRECIPITATION ADVANCING NORTHEASTWARD INTO THE FORECAST AREA DURING THE MID-MORNING TIMEFRAME AND LINGERING WELL THROUGH THE EARLY TO MID-AFTERNOON HOURS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. PRECIP TYPE WILL BE QUESTIONABLE ONCE AGAIN. BASED ON UPSTREAM OBS AND RUC/ETA SOUNDINGS, EXPECT THE PRECIP TO BE MAINLY RAIN ACROSS THE DETROIT METRO REGION, WITH RAIN OR SNOW NORTH OF THAT TO ALONG I-69. SUBSTANTIAL DIFFERENCES IN MODEL SOLUTIONS OFFERED BY THE NCEP SUITE ONCE AGAIN. THE ETA CONTINUES TO DEEPEN THE SURFACE LOW MUCH MORE AGGRESSIVELY THAN THE CONSENSUS OF THE GFS/NGM/WRFXX/ECMWF/ UKMET/CANADIAN SOLUTIONS. THE ETA IS SUPPORTED BY THE 13KM DEVELOPMENT RUC FROM FSL, THOUGH. MODEL TRENDS POINT TOWARD A SOLUTION MORE SIMILAR TO THAT OF THE GFS, BUT DEEPER - AS IT/S TREND CONTINUES TO SUPPORT AS EACH SUCCESSIVE RUN IS ABOUT 1MB DEEPER WITH THE LOW CENTER PRESSURE. THE ETA TREND IS SLIGHTLY WEAKER AND FARTHER EAST EACH CYCLE (INCLUDING THE NEW 06Z RUN). ANTICIPATE WIDESPREAD PRECIP TO MOVE NORTHWARD ACROSS THE FORECAST AREA EARLY THIS EVENING. THE COLUMN WILL CERTAINLY BE WARM ENOUGH TO SUPPORT AN ALL RAIN EVENT FOR THE DETROIT METRO REGION. THE TRANSITION REGION STILL APPEARS TO BE ALONG A SANDUSKY TO FLINT TO JACKSON LINE (EVEN SUPPORTED BY THE COOLER GFS SOLUTION)...WHERE PRECIP SHOULD START AS RAIN THEN MIX BEFORE CHANGING TO ALL SNOW PRIOR TO DAYBREAK. FARTHER NORTH AND WEST ACROSS THE SAGINAW VALLEY AND THE TIP OF THE THUMB...EXPECT THE EVENT TO BE MAINLY ALL SNOW. THE LIMITING FACTOR FOR ACCUMULATIONS WILL BE THE AVAILABLE MOISTURE IN THE COLD AIR. EXPECT THAT THE ACTIVE DEFORMATION ZONE COULD PRODUCE 1-3...POSSIBLY 2-4 INCHES OF SNOW FROM OWOSSO TO SAGINAW TO BAD AXE...WITH LOWER TOTALS IMMEDIATELY OUTSIDE THIS ZONE TO THE NORTH WHERE THE FORCING WILL BE WEAKER AND TO THE SOUTH WHERE MIXED PRECIP WILL LIMIT SNOW ACCUMULATIONS. && .LONG TERM... DRIER AIR QUICKLY MOVES INTO THE REGION ON WEDNESDAY IN THE WAKE OF THE DEPARTING SYSTEM. SO MUCH...THAT NOTHING MORE THAN SCATTERED CU EXPECT AFTER THE SYSTEM DEPARTS. WITH THE SUNSHINE AND SUBSIDENCE EXPECT A GUSTY WIND ON WEDNESDAY AS WE MIX UP TO 30 KNOTS AT 4 TO 5K FEET. GIVEN THE WESTERLY WIND AND SOME SNOW IN SOME AREAS...CANNOT SEE SOUTHEAST MICHIGAN GETTING UP TO THE NGM/FWC MOS NUMBERS EVEN WITH SUNSHINE. WILL GO TOWARD THE MUCH COOLER ETA/GFS MOS NUMBERS. LATE WEDNESDAY AND INTO WEDNESDAY NIGHT AND THURSDAY...COLD AIR ADVECTION INCREASES ACROSS THE GREAT LAKES AS BROAD WEST TO NORTHWEST FLOW ESTABLISHES ITSELF. NOT MUCH TO FOCUS ON THROUGH FRIDAY. DELTA T/S WILL BE COLD ENOUGH FOR LAKE EFFECT SNOW SHOWERS...BUT LOW INVERSION HEIGHTS...ESPECIALLY ACROSS THE SOUTHERN LAKES WILL REALLY HOLD LAKE EFFECT DOWN. DEPTH OF THE MOISTURE FROM WEDNESDAY NIGHT THRU FRIDAY IS LOW ENOUGH...SOME DOUBT ABOUT GETTING ICE IN THE CLOUDS DOWN TO THAT -8C TO -10C CLOUD TEMP. WOULDN/T BE TOO SURPRISED TO SEE SOME DRIZZLE/FREEZING DRIZZLE DURING THESE TWO DAYS BETWEEN THE CONVECTIVE SNOW SHOWERS. GFS AND WRFXX INDICATE A DECENT SHORTWAVE MOVING THROUGH THE SOUTHERN GREAT LAKES FOR FRIDAY NIGHT AND SATURDAY MORNING. CANADIAN IS WEAKER AND FARTHER NORTH. IN EITHER SOLUTION...ADDING A CHANCE OF SNOW FOR SOUTHEAST MICHIGAN THROUGH SATURDAY SEEMS WARRANTED. WILL ALSO LOWER HIGH TEMPS ON SATURDAY GIVEN THICKNESSES STAY IN THE 525 TO 531 RANGE WITH THE CLIPPER LIKE SHORTWAVE. SATURDAY SHOULD BE AT THE VERY LEAST COLDER THAN SUNDAY. && .DTX WATCHES/WARNINGS/ADVISORIES...SNOW ADVISORY LATE TONIGHT FOR BAY...SAGINAW...HURON...TUSCOLA..SHIAWASSEE...GENESEE...LAPEER...SANI LAC...LIVINGSTON COUNTIES. && $$ EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1150 AM EST TUE NOV 30 2004 .UPDATE... A SURFACE TROUGH STRETCHES FROM THE SOUTHERN MISSISSIPPI VALLEY NORTH-NORTHEASTWARD UP INTO EXTREME SOUTHEAST MICHIGAN THIS MORNING. WATER VAPOR IMAGERY SHOWING QUITE A BIT OF MOISTURE RIDING UP AND AROUND THIS TROUGH. A RIDGE AXIS SITS OVER THE CENTER OF OUR CWA AS OF 10AM...AND IS HELPING TO SUPPRESS THE PRECIP FORMING ALONG SURFACE TROUGH. WSR88-D SHOWING LIGHT RAIN OVER MOST OF OUR 2 SOUTHERN MOST COUNTIES...LENAWEE AND MONROE. MOST LOCATIONS ACROSS SOUTHEAST MICHIGAN STILL REPORTING IFR CONDITIONS WITH THE EXCEPTION OF THE FAR SOUTH WHERE DTW IS UP TO 2000 FEET. NORTHERN LOCATIONS ARE REPORTING LIFR WITH MBS AT 3/4SM AND 100 FEET. DON'T ANTICIPATE RAIN SHOWERS TO MAKE IT TOO FAR NORTH TODAY...WITH HIGH STILL IN PLACE. DTW MAY GET A FEW SHOWERS BUT DON'T THINK IT WILL GO MUCH FARTHER NORTH THAN THAT. WILL SEE A BREAK IN THE SHOWER ACTIVITY DURING THE AFTERNOON BEFORE MAIN BOUT OF RAIN COMES IN AROUND 6PM WORKING SOUTH TO NORTH ACROSS THE REGION AS THE SOUTHERN MISSISSIPPI VALLEY LOW WORKS ITS WAY CLOSER TO OUR AREA. NO CHANGES TO ZONES ARE PLANNED AT THIS TIME. CURRENT FORECAST LOOKS GOOD...WILL RESEND JUST TO REFRESH WORDING. LOOKING AHEAD A LITTLE TO TONIGHT. THE LATEST ETA AND NGM MODEL RUNS ARE IN A LITTLE BETTER AGREEMENT...WITH THE NGM MODEL NOW MUCH DEEPER WITH BOTH THE UPPER LOW AND SURFACE LOW...TO BE MORE IN LINE WITH THE ETA...ALSO THE NGM TRACK HAS TENDED A TAD BIT FURTHER TO THE WEST TO ALSO BE MORE IN LINE WITH THE ETA...BOTH BRING THE SURFACE LOW OVER WESTERN LAKE ERIE BY 4AM. BOTH MODELS ARE ALSO INDICATING A BIT HIGHER QPF VALUES. SOUNDINGS INDICATE A CHANGEOVER TO SNOW SHORTLY AFTER MIDNIGHT NORTH OF M-59...WITH ABOUT .45 INCHES OF PRECIP TO BE REALIZED ONCE THE SNOW STARTS TO IT'S END WEDNESDAY MORNING BETWEEN I69 AND M59...AND A LITTLE LESS QPF OVER THE SAGINAW VALLEY BUT AN EARLIER (JUST BEFORE MIDNIGHT) TRANSITION TO SNOW. TOTAL ACCUMULATIONS OF SNOW WILL BE THE FORECAST CHALLENGE AS THICKNESS VALUES ARE LESS THAN IMPRESSIVE FOR SNOW...ALTHOUGH THE ETA MODEL SUGGESTS ADVISORY LEVEL SNOWS NORTH OF M59 TO I69...STILL WAITING ON THE GFS MODEL TO COME IN TO SEE IF ITS TENDENCY IS MORE TOWARD THE ETA. A LOT TO LOOK AT THIS AFTERNOON. $$ SHULER .PREVIOUS DISCUSSION ISSUED AT 423 AM EST... .SHORT TERM... PERSISTENT STRATUS DECK ACROSS MUCH OF SOUTHERN LOWER MICHIGAN IS SHOWING SIGNS OF INCREASING IN DEPTH...AS PER LATEST 11-3.9 GOES IMAGERY. ANTICIPATE LITTLE IN THE WAY OF CHANGE WITH CLOUD COVER TODAY AS THE LOWER AND MID LEVEL MOISTURE CONTENT INCREASES FROM THE SOUTH IN ADVANCE OF THE DEVELOPING SYSTEM ACROSS THE LOWER MISSISSIPPI VALLEY REGION. THE OVERCAST WILL HELP KEEP THE DIURNAL TEMPERATURE RISE IN CHECK TODAY...EXPECT THAT HIGHS WILL BE SIMILAR TO YESTERDAY/S VALUES. LEADING WAVE OF WARM ADVECTION IN ADVANCE OF THE NEXT SYSTEM IS POISED ACROSS CENTRAL ILLINOIS AND INDIANA AND IS KICKING OFF A BAND OF SHOWERS. LATEST GUIDANCE CONTINUES TO POINT TOWARD THAT PRECIPITATION ADVANCING NORTHEASTWARD INTO THE FORECAST AREA DURING THE MID-MORNING TIMEFRAME AND LINGERING WELL THROUGH THE EARLY TO MID-AFTERNOON HOURS ACROSS THE SOUTHERN HALF OF THE FORECAST AREA. PRECIP TYPE WILL BE QUESTIONABLE ONCE AGAIN. BASED ON UPSTREAM OBS AND RUC/ETA SOUNDINGS, EXPECT THE PRECIP TO BE MAINLY RAIN ACROSS THE DETROIT METRO REGION, WITH RAIN OR SNOW NORTH OF THAT TO ALONG I-69. SUBSTANTIAL DIFFERENCES IN MODEL SOLUTIONS OFFERED BY THE NCEP SUITE ONCE AGAIN. THE ETA CONTINUES TO DEEPEN THE SURFACE LOW MUCH MORE AGGRESSIVELY THAN THE CONSENSUS OF THE GFS/NGM/WRFXX/ECMWF/ UKMET/CANADIAN SOLUTIONS. THE ETA IS SUPPORTED BY THE 13KM DEVELOPMENT RUC FROM FSL, THOUGH. MODEL TRENDS POINT TOWARD A SOLUTION MORE SIMILAR TO THAT OF THE GFS, BUT DEEPER - AS IT/S TREND CONTINUES TO SUPPORT AS EACH SUCCESSIVE RUN IS ABOUT 1MB DEEPER WITH THE LOW CENTER PRESSURE. THE ETA TREND IS SLIGHTLY WEAKER AND FARTHER EAST EACH CYCLE (INCLUDING THE NEW 06Z RUN). ANTICIPATE WIDESPREAD PRECIP TO MOVE NORTHWARD ACROSS THE FORECAST AREA EARLY THIS EVENING. THE COLUMN WILL CERTAINLY BE WARM ENOUGH TO SUPPORT AN ALL RAIN EVENT FOR THE DETROIT METRO REGION. THE TRANSITION REGION STILL APPEARS TO BE ALONG A SANDUSKY TO FLINT TO JACKSON LINE (EVEN SUPPORTED BY THE COOLER GFS SOLUTION)...WHERE PRECIP SHOULD START AS RAIN THEN MIX BEFORE CHANGING TO ALL SNOW PRIOR TO DAYBREAK. FARTHER NORTH AND WEST ACROSS THE SAGINAW VALLEY AND THE TIP OF THE THUMB...EXPECT THE EVENT TO BE MAINLY ALL SNOW. THE LIMITING FACTOR FOR ACCUMULATIONS WILL BE THE AVAILABLE MOISTURE IN THE COLD AIR. EXPECT THAT THE ACTIVE DEFORMATION ZONE COULD PRODUCE 1-3...POSSIBLY 2-4 INCHES OF SNOW FROM OWOSSO TO SAGINAW TO BAD AXE...WITH LOWER TOTALS IMMEDIATELY OUTSIDE THIS ZONE TO THE NORTH WHERE THE FORCING WILL BE WEAKER AND TO THE SOUTH WHERE MIXED PRECIP WILL LIMIT SNOW ACCUMULATIONS. && .LONG TERM... DRIER AIR QUICKLY MOVES INTO THE REGION ON WEDNESDAY IN THE WAKE OF THE DEPARTING SYSTEM. SO MUCH...THAT NOTHING MORE THAN SCATTERED CU EXPECT AFTER THE SYSTEM DEPARTS. WITH THE SUNSHINE AND SUBSIDENCE EXPECT A GUSTY WIND ON WEDNESDAY AS WE MIX UP TO 30 KNOTS AT 4 TO 5K FEET. GIVEN THE WESTERLY WIND AND SOME SNOW IN SOME AREAS...CANNOT SEE SOUTHEAST MICHIGAN GETTING UP TO THE NGM/FWC MOS NUMBERS EVEN WITH SUNSHINE. WILL GO TOWARD THE MUCH COOLER ETA/GFS MOS NUMBERS. LATE WEDNESDAY AND INTO WEDNESDAY NIGHT AND THURSDAY...COLD AIR ADVECTION INCREASES ACROSS THE GREAT LAKES AS BROAD WEST TO NORTHWEST FLOW ESTABLISHES ITSELF. NOT MUCH TO FOCUS ON THROUGH FRIDAY. DELTA T/S WILL BE COLD ENOUGH FOR LAKE EFFECT SNOW SHOWERS...BUT LOW INVERSION HEIGHTS...ESPECIALLY ACROSS THE SOUTHERN LAKES WILL REALLY HOLD LAKE EFFECT DOWN. DEPTH OF THE MOISTURE FROM WEDNESDAY NIGHT THRU FRIDAY IS LOW ENOUGH...SOME DOUBT ABOUT GETTING ICE IN THE CLOUDS DOWN TO THAT -8C TO -10C CLOUD TEMP. WOULDN/T BE TOO SURPRISED TO SEE SOME DRIZZLE/FREEZING DRIZZLE DURING THESE TWO DAYS BETWEEN THE CONVECTIVE SNOW SHOWERS. GFS AND WRFXX INDICATE A DECENT SHORTWAVE MOVING THROUGH THE SOUTHERN GREAT LAKES FOR FRIDAY NIGHT AND SATURDAY MORNING. CANADIAN IS WEAKER AND FARTHER NORTH. IN EITHER SOLUTION...ADDING A CHANCE OF SNOW FOR SOUTHEAST MICHIGAN THROUGH SATURDAY SEEMS WARRANTED. WILL ALSO LOWER HIGH TEMPS ON SATURDAY GIVEN THICKNESSES STAY IN THE 525 TO 531 RANGE WITH THE CLIPPER LIKE SHORTWAVE. SATURDAY SHOULD BE AT THE VERY LEAST COLDER THAN SUNDAY. && .DTX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ MANN/RBP EXPERIMENTAL GRAPHICAL FORECASTS ARE AVAILABLE ONLINE AT HTTP://WWW.CRH.NOAA.GOV/DTX (ALL LOWER CASE) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1010 AM EST TUE NOV 30 2004 .DISCUSSION... ARCTIC FRONT LINES UP FROM FAR SE MANITOBA CANADA TO JUST N OF YQT THEN JOGS NE TOWARD E SHORE OF JAMES BAY. TEMP GRADIANT ALONG FRONT IS SIGNIFICANT WITH READINGS IN THE LOW-MID 20S AHEAD OF BOUNDARY AND FALLING INTO LOW SINGLE DIGITS...EVEN BLO ZERO...BEHIND IT. SOURCE REGION OF COLD AIRMASS OVR N MANTIOBA/SASKATCHEWAN SHOWS BONE CHILLING TEMPS FROM 20 BELOW TO 30 BELOW. WINDS/TEMPS MAIN CONCERN IN SHORT TERM AS SKIES SHOULD STAY MAINLY CLEAR WITH BAROCLINIC ZONE STAYING TO OUR NORTH TODAY AND S STREAM CLOUDS/PCPN REMAINING TO THE S. PRESSURE GRADIANT BETWEEN ARCTIC BOUNDARY AND HIGH PRES RIDGE OVR LWR LAKES SLOWLY RELAXING. 12Z INL SOUNDING SHOWED LLJ AROUND 40KT AS LOW AS 900MB. RUC INITIALIZED THIS FEATURE BETTER THAN ETA AND SHOWS LLJ LINGERING OVR LK SUPERIOR THROUGH EARLY AFTN. OVER LAND...COMBINATION OF STRONG MORNING INVERSION AND WEAKENING PRESSURE GRADIANT SHOULD KEEP WIND SPEEDS IN CHECK THIS AFTN. 10-20MPH WINDS (A BIT HIGHER OVR PORTIONS OF KEWEENAW PENINSULA) LOOK FINE. AIRMASS FOR THIS AFTN COMES FROM S HALF OF MN PER SFC TRAJECTORIES. TEMPS YDY AFTN THERE WERE AROUND 32F. A BIT MORE SUNSHINE AND INCREASING MIXING HEIGHTS (925-900MB PER 12Z MPX SOUNDING) SUPPORT CURRENT GRIDDED MAX TEMPS IN MID 30S TO AROUND 40 (GENERAL AGREEMENT WITH LATEST GUIDANCE TOO). MADE A FEW MINOR UPDATES TO GRIDS...BUT OVERALL NO NEED FOR AN TEXT ZFPMQT UPDATE AT THIS TIME. .PREV DISCUSSION ISSUED AT 359 AM EST THIS MORNING... ARCTIC FRONT SAGS ACROSS LAKE SUPERIOR LATE TONIGHT AS INITIAL SHORTWAVE COMES THRU...SETTING UP CAA FOR WED AND A SHIFT TO A NWLY WIND. DYNAMICS FROM WAVE ITSELF ARE VERY WEAK...AND AMS IS QUITE DRY...BUT WITH FRONTAL CONVERGENCE WILL BRING CHC FLURRIES ALL THE WAY TO THE SOUTHERN ZONES. OTHERWISE WOULD EXPECT CHANCE OF SHSN BY EARLY WED ON THE KEWEENAW...AND TO REMAINDER OF NRN TIER WED MORNING. HAVE UPPED POPS TO LIKELY ON THE KEWEENAW AND IN THE EAST WED AFTN/NIGHT AS CONVERGENCE SHOULD BE FOCUSED IN THESE AREAS. GFS SHOWS A BIT HIGHER INVERSION HEIGHTS THAN THE ETA (6 KFT COMPARED TO 5KFT OR LESS)...BUT WITH TEMPS IN MOIST BLYR SUFFICIENTLY COLD FOR SNOW GROWTH AND DELTA-TS NEAR 18C SHOULD SEE SOME ACCUMULATION. HAVE PAINTED 1-3 INCHES IN GRIDS FOR WED NIGHT...BUT IF CONVERGENCE REMAINS OVER ONE PLACE LONG ENOUGH AMTS COULD BE A BIT HIGHER. HAVE SIDED WITH THE GFS/UKMET AS IT SHOWS A BOUNDARY LINGERING OVER THE AREA THROUGH THU...AND IN FACT SHIFTING NORTH A BIT THU IN RESPONSE TO NEXT APPROACHING CLIPPER. TOUGH TO FIGURE WHERE CONVERGENCE WILL SET UP THU/THU NIGHT...BUT WITH SHORTWAVE COMING THRU THERE IS POTENTIAL FOR MORE SIGNIFICANT ACCUM DURING THIS TIME (ALONG A DOMINANT BAND). BEST CHANCE OF THIS WILL BE ON THE KEWEENAW AND ALONG THE PICTURED ROCKS SHORE. WINDS LOOK TO BE TOO WNWLY FOR MUCH IN GOGEBIC OR MARQUETTE CTYS. HAVE RAISED POPS TO 50 IN FAVORED SPOTS...BUT HAVE NOT GONE TO LIKELY JUST YET GIVEN THE MODEL DIFFERENCES (ETA SHOWS LITTLE SFC REFLECTION OF TROF). GFS SHOWS INVERSION HEIGHTS RISING TO NEAR 700MB AT CMX AND ERY...SO POTENTIAL IS THERE. THIS WILL HAVE TO BE WATCHED...AND WILL CONTINUE TO HIGHLIGHT IN THE HWO. LES WINDS DOWN FRI AS WINDS BACK IN RESPONSE TO DEEPER TROF (OF PACIFIC ORIGIN) DRIVING INTO THE NRN PLAINS. HAVE ADDED MENTION OF LIGHT SNOW EVERYWHERE FRI AFTN/NIGHT AS THIS FEATURE COMES THRU... OFFERING A PERIOD OF MODERATE Q-VECTOR CONVERGENCE. POSSIBILITY EXISTS FOR SOME ENHANCEMENT OF OF LAKE MICHIGAN AS WELL...WITH SLY FLOW AND H8 TEMPS STILL ON THE ORDER OF -8C AT THE ONSET. HAVE MADE NO CHANGES TO SAT AND BEYOND AS MODELS DIVERGE A GREAT DEAL BY THIS WEEKEND. UKMET CONTINUES TO ADVERTISE A PUSH OR ARCTIC AIR BY SUN WHEREAS THE GFS HAS WARMER ZONAL FLOW FOR THE UPPER GREAT LAKES. ECMWF IS A COMPROMISE. WILL LET THE DAY SHIFT TAKE A CLOSER LOOK. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DISCUSSION...JLA PREV DISCUSSION...JKL mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 955 PM CST TUE NOV 30 2004 .DISCUSSION... LAST VESTIGES OF SNOW MOVING OUT OF CFWA ATTM AN HAVE UPDATED GRIDS TO INDICATE SNOW THREAT HAS ENDED. BACK EDGE OF MID-LEVEL CLOUDS ABOUT HALF WAY ACROSS MISSOURI...AND SHOULD CLEAR EASTERN FRINGES OF CFWA SHORTLY AFTER MIDNIGHT. WEST WINDS OF PLENTY OF BOUNDARY LAYER MOISTURE WILL KEEP TEMPERATURES FROM FALLING OFF TOO RAPIDLY. TWEAKED GOING FORECAST MINS SLIGHTLY...BUT SEEMED REASONABLE BASED ON CURRENT TEMPERATURE AND DEWPOINT TRENDS. SF && .PREV DISCUSSION... 300 PM TUE... THE CENTER OF THE ELONGATED UPPER LOW RESPONSIBLE FOR OUR SNOW TODAY IS NEARLY ON TOP OF KANSAS CITY ACCORDING TO RUC ANALYSIS AT 20 UTC. POSITIVE VORTICITY ADVECTION FOR THE REMAINDER OF THE AFTERNOON AND EVENING WILL BE OVER NORTH CENTRAL AND NORTHEAST MISSOURI. DESPITE NUMEROUS SLOW MOVING BANDS OF LIGHT TO OCCASIONALLY MODERATE SNOW OVER KANSAS CITY TODAY, MOST AREAS MEASURED JUST AN INCH OR SO. WARM GROUND MELTED MUCH OF THE SNOW AS IT FELL, AND ACCUMULATIONS WERE GENERALLY RESTRICTED TO GRASSY SURFACES. I'M NOT EXPECTING ACCUMULATIONS EAST OF KANSAS CITY TO BE ANY MORE SIGNIFICANT THROUGH THIS EVENING. VISIBLE SATELLITE IMAGERY SHOWS THAT THE CHANGE FROM SNOW TO MOSTLY CLEAR SKIES IS PRETTY ABRUPT. THE NORTHWEST TIP OF MISSOURI IS EXPERIENCING SUNSHINE WHILE THE KANSAS CITY AREA HAS VISIBILITIES OF LESS THAN A MILE AND SNOW. KOCH THE LAST HALF OF THE FORECAST WILL START OUT DRY AS KANSAS AND MISSOURI LANGUISH IN BETWEEN WINTERY STORM SYSTEMS. LATE THIS WORK WEEK TEMPERATURES WILL REMAIN COOL...RUNNING AT OR JUST BELOW NORMAL AS NORTHWEST WINDS SLOWLY BECOME WESTERLY. BY THIS WEEKEND TEMPERATURES ARE EXPECTED TO REBOUND ABOVE NORMAL AS SOUTHERLY WINDS RETURNED TO THE REGION AHEAD OF THE NEXT SHORTWAVE EJECTING OUT OF THE DESERT SOUTHWEST. LATEST RUNS OF THE GFS HAVE SLOWED THE PROGRESSION OF THE SHORTWAVE OUT OF THE SOUTHWEST...WHICH HAS BROUGHT IT MORE IN LINE WITH THE ECMWF AND CANADIAN MODELS. STILL SOME QUESTION OF WHETHER THE SYSTEM WILL REMAIN AN OPEN WAVE...AS CURRENTLY FORECAST...OR IF LATER RUNS WILL CLOSE IT OFF SLOWING IT DOWN EVEN MORE. ANYWAY...LEFT GOING FORECAST MOSTLY UNCHANGED EXCEPT FOR TWO SMALL DETAILS. ONE...I STRETCHED OUT THE CHANCE OF PRECIP INTO MONDAY NIGHT DUE TO THE SLOWING OF THE MODEL SOLUTIONS...AND TWO I ADDED A MIX OF RAIN AND/OR SNOW TO THE NORTHERN TIER OF COUNTIES FOR PERIODS WHEN THE TEMPERATURES LOOKED TO WARRANT IT. CUTTER 352 AM... WATCHING THE SNOW BANDS DISINTEGRATE ON RADAR THIS MORNING. ALTHOUGH NORTHWEST MISSOURI HAS SNOWED MOST OF THE NIGHT...THE SNOWFALL AMOUNTS HAVE BEEN MINIMAL. MOST LOCATIONS HAVE A DUSTING ON STREETS AND AN INCH OR LESS ON THE GRASS. MOVING FARTHER SOUTH TO THE I70 CORRIDOR...THE SNOW HAS BEEN SPOTTY AT BEST THIS MORNING. IT APPEARS THAT DRY AIR INTRUSION FROM THE NORTH IS SOMEWHAT TO BLAME...AS DEFORMATION ZONE REALLY HAS NOT SET UP. UPPER LEVEL PVA IS UPON US...AND DOESN'T SEEM TO BE CAUSING ADDITIONAL PRECIP TO FALL. THE BEST CHANCES OF MORE PRECIPITATION FOR THIS AREA IS IN THE SOUTHEASTERN CWA...AS THE ECHOES COMING OUT OF NORTHEASTERN OKLAHOMA MAY AFFECT THEM. BOTH THE ETA AND GFS SHOW THAT AREA MAY SEE SOME ADDITIONAL ISENTROPIC LIFT THIS MORNING...BUT MINIMAL...AND EXITING BY NOON. MAINLY WAITING FOR THE TROF TO FINALLY SWING THROUGH...WHICH MAY PROVIDE ENOUGH LIFT TO SQUEEZE OUT SOME MEASURABLE PRECIPITATION. AS FAR AS THE HEADLINES GO...HAVE SOME REPORTS OF ICY ROADS AROUND THE AREA BUT MAINLY DUE TO THE RAIN FROM YESTERDAY AFTERNOON FREEZING WITH A DUSTING OF SNOW ON TOP. PLAN ON CANCELING THE SNOW ADVISORY IN AFFECT...BUT WILL STRONGLY WORD PRODUCTS THAT DRIVING CONDITIONS MAY STILL BE DICEY DUE TO ICY ROADS. TEMPERATURES WILL WARM JUST A BIT TODAY...WILL SEE TEMPS IN THE MIDDLE 30S. AS THE LOW SWINGS OFF...SHOULD SEE CLEARING AROUND NIGHTFALL. THIS WILL CAUSE TEMPS TO DROP TONIGHT INTO THE 20S. NO OTHER MAJOR CHANGES MADE. LVQ && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE MO...NONE $$ WFO EAX mo AREA FORECAST DISCUSSION...AVIATION UPDATE. NATIONAL WEATHER SERVICE SPRINGFIELD MO 545 PM CST TUE NOV 30 2004 .DISCUSSION... WATER VAPOR IMAGERY AND RUC MODEL ANALYSIS SHOWED THE UPPER TROUGH MIGRATING EASTWARD ACROSS CENTRAL U.S. TUESDAY AFTERNOON. THE HEAVIEST PRECIPITATION HAD MOVED EAST OF THE FORECAST AREA BUT A MIXTURE OF LIGHT PRECIPITATION LINGERED ACROSS THE OZARKS REGION. LIGHT SNOW WAS FALLING FROM EXTREME SOUTHEAST KANSAS INTO CENTRAL MISSOURI BUT TEMPERATURES REMAINED A DEGREE OR TWO ABOVE FREEZING. THE UPPER TROUGH WILL TRANSLATE TO THE EAST ACROSS THE REGION TONIGHT. THE LIGHT RAIN AND SNOW WILL TAPER OFF TO DRIZZLE AS A MID LEVEL DRY INTRUSION SPREADS EAST. THE LIGHT SNOW WILL AFFECT AREAS MAINLY NORTH OF INTERSTATE 44 EARLY EARLY THIS EVENING BUT LITTLE IF ANY ACCUMULATION IS EXPECTED. IT APPEARS FAIRLY RAPID CLEARING WILL TAKE PLACE TONIGHT AS NEGATIVE VORTICITY ADVECTION AND ISENTROPIC DESCENT SPREAD EAST IN THE WAKE OF THIS SYSTEM. SUFFICIENT CLEARING IS EXPECTED TO ALLOW LOWS TO FALL INTO THE LOWER AND MIDDLE 20S ACROSS MOST OF THE FORECAST AREA. A BROAD NORTHWESTERLY ALOFT WILL SET UP IN THE WAKE OF THE DEPARTING TROUGH OVER THE NEXT FEW DAYS. SURFACE HIGH PRESSURE WILL SINK TO THE SOUTHWEST OF THE AREA WEDNESDAY PROVIDING A WEST TO SOUTHWEST FLOW. A WEAK AND QUICK MOVING SHORTWAVE WILL SLIDE SOUTHEAST ACROSS THE REGION THURSDAY BUT NO PRECIPITATION IS EXPECTED AS DEEP MOISTURE WILL BE LACKING. HOWEVER A REINFORCEMENT OF THE COOL AIRMASS WILL FOLLOW ITS PASSAGE. YET ANOTHER MORE VIGOROUS SHORTWAVE IS PROGGED TO DROP SOUTHEAST ACROSS THE MIDWEST FRIDAY NIGHT. IT APPEARS THAT THE BEST DYNAMICS WITH THIS SYSTEM WILL BE NORTHEAST OF THE AREA AND MOISTURE WILL AGAIN BE LIMITED. THEREFORE NO PRECIPITATION IS EXPECTED AT THIS TIME. THE NEXT CHANCE OF PRECIPITATION WILL ARRIVE SUNDAY NIGHT OR MONDAY AS THE FLOW ALOFT FLATTENS AND A SHORTWAVE APPROACHES FROM THE WEST. FOSTER && .AVIATION... SNOW WILL END IN THE SPRINGFIELD AREA BY 02Z. JOPLIN SHOULD NOT HAVE ANY PROBLEMS WITH SNOW AFTER 00Z. AS FOR CEILINGS, EXPECT THE MVFR CONDITIONS TO RAPIDLY BECOME VFR BY 3Z WITH SOME MID LEVEL DECK POSSIBLE NORTHEAST OF SPRINGFIELD THROUGH MIDNIGHT. EXPECT A WESTERLY WIND TO BECOME SOUTH/SOUTHWEST WEDNESDAY MORNING. JLT && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. $$ WFO SGF mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 300 PM CST TUE NOV 30 2004 .DISCUSSION... THE CENTER OF THE ELONGATED UPPER LOW RESPONSIBLE FOR OUR SNOW TODAY IS NEARLY ON TOP OF KANSAS CITY ACCORDING TO RUC ANALYSIS AT 20 UTC. POSITIVE VORTICITY ADVECTION FOR THE REMAINDER OF THE AFTERNOON AND EVENING WILL BE OVER NORTH CENTRAL AND NORTHEAST MISSOURI. DESPITE NUMEROUS SLOW MOVING BANDS OF LIGHT TO OCCASIONALLY MODERATE SNOW OVER KANSAS CITY TODAY, MOST AREAS MEASURED JUST AN INCH OR SO. WARM GROUND MELTED MUCH OF THE SNOW AS IT FELL, AND ACCUMULATIONS WERE GENERALLY RESTRICTED TO GRASSY SURFACES. I'M NOT EXPECTING ACCUMULATIONS EAST OF KANSAS CITY TO BE ANY MORE SIGNIFICANT THROUGH THIS EVENING. VISIBLE SATELLITE IMAGERY SHOWS THAT THE CHANGE FROM SNOW TO MOSTLY CLEAR SKIES IS PRETTY ABRUPT. THE NORTHWEST TIP OF MISSOURI IS EXPERIENCING SUNSHINE WHILE THE KANSAS CITY AREA HAS VISIBILITIES OF LESS THAN A MILE AND SNOW. KOCH THE LAST HALF OF THE FORECAST WILL START OUT DRY AS KANSAS AND MISSOURI LANGUISH IN BETWEEN WINTERY STORM SYSTEMS. LATE THIS WORK WEEK TEMPERATURES WILL REMAIN COOL...RUNNING AT OR JUST BELOW NORMAL AS NORTHWEST WINDS SLOWLY BECOME WESTERLY. BY THIS WEEKEND TEMPERATURES ARE EXPECTED TO REBOUND ABOVE NORMAL AS SOUTHERLY WINDS RETURNED TO THE REGION AHEAD OF THE NEXT SHORTWAVE EJECTING OUT OF THE DESERT SOUTHWEST. LATEST RUNS OF THE GFS HAVE SLOWED THE PROGRESSION OF THE SHORTWAVE OUT OF THE SOUTHWEST...WHICH HAS BROUGHT IT MORE IN LINE WITH THE ECMWF AND CANADIAN MODELS. STILL SOME QUESTION OF WHETHER THE SYSTEM WILL REMAIN AN OPEN WAVE...AS CURRENTLY FORECAST...OR IF LATER RUNS WILL CLOSE IT OFF SLOWING IT DOWN EVEN MORE. ANYWAY...LEFT GOING FORECAST MOSTLY UNCHANGED EXCEPT FOR TWO SMALL DETAILS. ONE...I STRETCHED OUT THE CHANCE OF PRECIP INTO MONDAY NIGHT DUE TO THE SLOWING OF THE MODEL SOLUTIONS...AND TWO I ADDED A MIX OF RAIN AND/OR SNOW TO THE NORTHERN TIER OF COUNTIES FOR PERIODS WHEN THE TEMPERATURES LOOKED TO WARRANT IT. CUTTER && 910 AM... I PLAN TO MAKE SOME UPDATES TO THE FORECAST SOON TO INCREASE SNOW CHANCES AND AMOUNTS OVER NORTHEAST KANSAS AND MUCH OF NORTHERN MISSOURI. THE 12Z TOPEKA SOUNDING SHOWED WHY SNOW WAS SLOW DEVELOPING THIS MORNING. DRY AIR ABOVE 700MB PRECLUDED DENDRITIC GROWTH UNTIL ABOUT SUNRISE. (THIS EXPLAINS THE HEAVY DRIZZLE DURING THE DRIVE INTO THE OFFICE THIS MORNING). AS THE UPPER LOW NUDGES CLOSER TO OUR REGION, ENOUGH VERTICAL LIFT (AND SUBSEQUENT MOISTURE IN THE -15 TO -20C LAYER) IS PRESENT TO CAUSE A BAND OF LIGHT TO OCCASIONALLY MODERATE SNOW TO DEVELOP. IR SATELLITE IMAGERY SHOWS A BAND OF -15 TO -22C CLOUD FROM WICHITA TO MANHATTAN ALONG THE AXIS OF HIGHEST VORTICITY. THE SLOW MOVEMENT OF THE UPPER LOW WILL KEEP EASTERN KANSAS AND WESTERN MISSOURI IN POSITIVE VORTICITY ADVECTION THROUGH A GOOD PORTION OF THE AFTERNOON. SINCE DEEP LAYER MOISTURE WILL LIKELY BE A LIMITING FACTOR IN SNOW FLAKE FORMATION TODAY, I EXPECT THE SNOW BAND TO MEANDER BACK AND FORTH TODAY. PRECIPITATION WILL LIKELY FLUCTUATE BETWEEN LIGHT SNOW AND DRIZZLE DEPENDING ON WHETHER ICE CRYSTALS ARE PRESENT ALOFT. SNOW AMOUNTS WILL PROBABLY BE LIMITED TO AN INCH OR TWO AS SNOW MELTS BETWEEN BOUTS OF ACCUMULATION. KOCH && .PREV DISCUSSION... 352 AM... WATCHING THE SNOW BANDS DISINTEGRATE ON RADAR THIS MORNING. ALTHOUGH NORTHWEST MISSOURI HAS SNOWED MOST OF THE NIGHT...THE SNOWFALL AMOUNTS HAVE BEEN MINIMAL. MOST LOCATIONS HAVE A DUSTING ON STREETS AND AN INCH OR LESS ON THE GRASS. MOVING FARTHER SOUTH TO THE I70 CORRIDOR...THE SNOW HAS BEEN SPOTTY AT BEST THIS MORNING. IT APPEARS THAT DRY AIR INTRUSION FROM THE NORTH IS SOMEWHAT TO BLAME...AS DEFORMATION ZONE REALLY HAS NOT SET UP. UPPER LEVEL PVA IS UPON US...AND DOESN'T SEEM TO BE CAUSING ADDITIONAL PRECIP TO FALL. THE BEST CHANCES OF MORE PRECIPITATION FOR THIS AREA IS IN THE SOUTHEASTERN CWA...AS THE ECHOES COMING OUT OF NORTHEASTERN OKLAHOMA MAY AFFECT THEM. BOTH THE ETA AND GFS SHOW THAT AREA MAY SEE SOME ADDITIONAL ISENTROPIC LIFT THIS MORNING...BUT MINIMAL...AND EXITING BY NOON. MAINLY WAITING FOR THE TROF TO FINALLY SWING THROUGH...WHICH MAY PROVIDE ENOUGH LIFT TO SQUEEZE OUT SOME MEASURABLE PRECIPITATION. AS FAR AS THE HEADLINES GO...HAVE SOME REPORTS OF ICY ROADS AROUND THE AREA BUT MAINLY DUE TO THE RAIN FROM YESTERDAY AFTERNOON FREEZING WITH A DUSTING OF SNOW ON TOP. PLAN ON CANCELING THE SNOW ADVISORY IN AFFECT...BUT WILL STRONGLY WORD PRODUCTS THAT DRIVING CONDITIONS MAY STILL BE DICEY DUE TO ICY ROADS. TEMPERATURES WILL WARM JUST A BIT TODAY...WILL SEE TEMPS IN THE MIDDLE 30S. AS THE LOW SWINGS OFF...SHOULD SEE CLEARING AROUND NIGHTFALL. THIS WILL CAUSE TEMPS TO DROP TONIGHT INTO THE 20S. NO OTHER MAJOR CHANGES MADE. LVQ && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE MO...NONE $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 1032 AM CST TUE NOV 30 2004 .DISCUSSION...UPDATE CHALLENGE WILL BE TEMPERATURES WITH COLD FRONT POSITIONED ALONG INTERNATIONAL BORDER. TEMPERATURES CURRENTLY RECOVERING NICELY INTO THE MID/UPPER 20F RANGE. LOOKING AT MODEL INITIALIZATION 12Z GFS APPEARS TO HAVE BETTER HANDLE ON LOW LEVEL (925MB) TEMPERATURE FIELD...WITH 12Z ETA/RUC TOO COLD. FOLLOWING GFS WOULD BRING COLD FRONT FROM A LANGDON TO GRAND FORKS TO BAUDETTE LINE BY 21Z. 925MB COLD AIR ADVECTION BEHIND FRONT SHOULD MEAN STEADY TEMPERATURES AFTER NOON FOR THIS AREA. EXPECT TEMPERATURES TO CLIMB TO NEAR CURRENT FORECASTED MAX VALUES AND THEN STEADY OFF AFTER NOON. WITH CLOUD COVER ALSO EXPECTED TO INCREASE AFTER NOON THIS SEEMS REASONABLE. OTHERWISE AREAS SOUTH OF FRONT WILL BE ABLE TO RECOVER AS PER USUAL DIURNAL TREND. WILL DO A MINOR UPDATE FOR TEMPERATURE TREND BEHIND COLD FRONT AND CLOUD COVER NEAR INTERNATIONAL BORDER. EXPECT UPDATE TO BE SENT BY 1100AM. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OHIO 950 PM EST TUE NOV 30 2004 .SHORT TERM UPDATE EARLY OUTPUT FROM THE ETA 00Z RUN INDICATES LOW WILL TRACK TO THE NORTH TOWARD TOLEDO AND THEN MAKE THE RIGHT TURN UP LAKE ERIE. CURRENT SURFACE OBSERVATIONS INDICATE LOW CENTER IS OVER SOUTHEAST INDIANA AND THIS IS RIGHT ON TRACK WITH 00Z ETA TRACK. THE LOW HAS BEEN WOBBLING SLIGHTLY AS IT TRACKS NORTH. THE AXIS OF GREATEST PRESSURE FALLS EXTENDS NORTH FROM THE LOW CENTER INTO TOLEDO WITH ANOTHER AXIS TO THE EAST OVER COLUMBUS. LOW SHOULD TRACK AS ETA PROJECTS AS HIGH PRESSURE ON THE EAST COAST BEGINS TO SHIFT OUT TO SEA. RAIN WILL CONTINUE TO LIFT NORTH WITH A BREAK FOR A PERIOD OF TIME IN THE ACTIVITY. THEN AS LOW MOVES NORTHEAST...WE WILL SEE A WRAP AROUND PRECIPITATION BAND MOVE INTO THE AREA. ETA 850 MB TO 1000 MB THICKNESS FROM CURRENT 00Z RUN INDICATES RAIN SHOULD BECOME MIXED WITH OR CHANGE TO SNOW IN THE WESTERN PORTIONS OF THE FORECAST AREA AROUND 12Z IN THE MORNING. REST OF THE AREA SHOULD SEE RAIN BECOMING MIXED WITH SNOW THROUGH THE MORNING HOURS. WILL SEND AN UPDATE TO ADJUST WINDS IN THE TEXT BASED ON CURRENT FORECAST TRACK OF THE LOW. WILL HAVE TO KEEP AN EYE ON WINDS FOR WEDNESDAY AS GRADIENT TIGHTENS UP AND LOW DEEPENS WITH TIME. .PREVIOUS SHORT TERM (TNGT THRU THURS) LRG AREA OF RN MOVG INTO THE OH VLY. RN ASSOCD WI A DVLPG AND DEEPENG LOW. RUC/ETA HAVE THE TRACK OF THE LOW FURTHER W MOVG INTO WRN LERI WHILE THE GFS, THE FAVORED MODEL HERE, CURVG NE THRU NE OH INTO WRN NY BY WED MRNG. AS A RESULT THE WINDS WL BE TURNG INTO THE SW/W THEN NW SOONER RATHER THAN LATER AND INCRASG RPDLY. WDSPRD RN SHIELD ACOMPANYS THIS LOW AND A PUSH OF WRM AIR AHD OF THE LOW WL HOLD UP TEMPS IN THE 35-40 RANGE BFR THE COLDER AIR RUSHES IN VIA THE NW FLOW ON THE BACKSIDE AFT THE PASS OF THE LOW WED. SOME RESIDUAL MSTR LEFT OVR WED MRNG MAY SEE A RN/SNW MIX AND PERHAPS ALL SNW FOR A BRF PD WED MRNG. DRY SLOT WORKS IN WED AFTN AND INTO THE NGT OVR ALL BUT THE NE. CULD BE SOME LK EFFECT CLDS/PCPN AND IN THE FORM OF SNW AS TEMPS DROP INTO THE 20S BY THURS MRNG. A FAIR WX PATERN SETS UP WI WK HI BLDG IN FRM THE S SHUOLD KEEP MST AREAS DRY. .LONG TERM (FRI-WED) AS THE HI EXITS TO THE E FRI, ANOTHER CDFNT DROPS DWN AND CROSSES THE AREA FRI NGT INTO SAT. TEMPS TO BE COLD ENUF FOR SCT SNSH AND PERHAPS LK ENHANCED IN THE NE ON SAT. A CHG IN THE JET TO A MORE ZONAL AND SW FLOW INTO ERY NXT WEEK MAY PUSH TEMPS INTO THE 40S AND EVEN LWR 50S BY WED. .AVIATION (18Z-18Z)... LOW PRES WITH INV TROF FROM WRN TN TO MOV TO OH VLY. THE SYS WL BE ACCOMPANIED BY AMPLE MOISTURE AND WARM AIR ADVECTION. LOOK FOR CIGS AND VSBYS TO LOWER TO IFR CONDS THIS EVE AND TNGT AND CONT THRU EARLY WED. AS THE LOW PRES PULLS NE WARD INTO WRN PA AND WRN NEW YORK LOOK FOR STRONG NW WINDS AND SLOWLY IMPROVING CIGS AND VSBYS WED AFTN. && .CLE WATCHES/WARNINGS/ADVISORIES. OH...GALE LERI. PA...GALE LERI. && SHORT TERM UPDATE...LOMBARDY SHORT TERM...20 LONG TERM...20 AVIATION...COMEAUX && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OHIO 355 PM EST TUE NOV 30 2004 .SHORT TERM (TNGT THRU THURS) LRG AREA OF RN MOVG INTO THE OH VLY. RN ASSOCD WI A DVLPG AND DEEPENG LOW. RUC/ETA HAVE THE TRACK OF THE LOW FURTHER W MOVG INTO WRN LERI WHILE THE GFS, THE FAVORED MODEL HERE, CURVG NE THRU NE OH INTO WRN NY BY WED MRNG. AS A RESULT THE WINDS WL BE TURNG INTO THE SW/W THEN NW SOONER RATHER THAN LATER AND INCRASG RPDLY. WDSPRD RN SHIELD ACOMPANYS THIS LOW AND A PUSH OF WRM AIR AHD OF THE LOW WL HOLD UP TEMPS IN THE 35-40 RANGE BFR THE COLDER AIR RUSHES IN VIA THE NW FLOW ON THE BACKSIDE AFT THE PASS OF THE LOW WED. SOME RESIDUAL MSTR LEFT OVR WED MRNG MAY SEE A RN/SNW MIX AND PERHAPS ALL SNW FOR A BRF PD WED MRNG. DRY SLOT WORKS IN WED AFTN AND INTO THE NGT OVR ALL BUT THE NE. CULD BE SOME LK EFFECT CLDS/PCPN AND IN THE FORM OF SNW AS TEMPS DROP INTO THE 20S BY THURS MRNG. A FAIR WX PATERN SETS UP WI WK HI BLDG IN FRM THE S SHUOLD KEEP MST AREAS DRY. .LONG TERM (FRI-WED) AS THE HI EXITS TO THE E FRI, ANOTHER CDFNT DROPS DWN AND CROSSES THE AREA FRI NGT INTO SAT. TEMPS TO BE COLD ENUF FOR SCT SNSH AND PERHAPS LK ENHANCED IN THE NE ON SAT. A CHG IN THE JET TO A MORE ZONAL AND SW FLOW INTO ERY NXT WEEK MAY PUSH TEMPS INTO THE 40S AND EVEN LWR 50S BY WED. .AVIATION (18Z-18Z)... LOW PRES WITH INV TROF FROM WRN TN TO MOV TO OH VLY. THE SYS WL BE ACCOMPANIED BY AMPLE MOISTURE AND WARM AIR ADVECTION. LOOK FOR CIGS AND VSBYS TO LOWER TO IFR CONDS THIS EVE AND TNGT AND CONT THRU EARLY WED. AS THE LOW PRES PULLS NE WARD INTO WRN PA AND WRN NEW YORK LOOK FOR STRONG NW WINDS AND SLOWLY IMPROVING CIGS AND VSBYS WED AFTN. && .CLE WATCHES/WARNINGS/ADVISORIES. OH...GALE LERI. PA...GALE LERI. && SHORT TERM...20 LONG TERM...20 AVIATION...COMEAUX && $$ oh AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 925 PM EST TUE NOV 30 2004 .SHORT TERM (REST OF TONIGHT)... SFC LOW HAS RAPIDLY CLIMBED FROM THE DEEP SOUTH TO THE OHIO RIVER VALLEY THIS EVENING. ASSOCIATED FRONTS HAVE ALSO MADE PROGRESS APPROACHING THE FA. RADAR COMPOSITE CLEARLY DEPICTS THE LOCATION OF THE COLD FRONT ACROSS CENTRAL KY...TN...AND AL. FINE LINE DEPICTED ON THE KJGX AND KCAE RADARS MAY BE ASSOCIATED WITH THE PASSAGE OF THE WARM FRONT. MESOETA SHOWS RESPECTABLE 3 HR MSLP PRESSURE CHANGE ALONG THE FRONT LATE TONIGHT. THE PRESSURE WILL BEGIN A SHARP RISE AFTER 9Z OVER THE TN/NC LINE TONIGHT ALONG WITH H85 DRY/CAA. H85 WINDS INCREASE TO AT LEAST 45KTS AND BELIEVE THAT WITH STRONG SUBSIDENCE THESE WINDS WOULD MIX TO THE SFC AT WIND ADVISORY CRITERIA OVER THE NRN MTNS. THE GREATEST PRESSURE RISES TAKE PLACE OVER THE EXTREME WESTERN NC BETWEEN 9Z-12Z. HOWEVER...THE H85 WINDS DO NOT REACH THE LEVELS DEPICTED FURTHER NORTH...WILL POST A LAKE WIND ADVISORY FOR THE CENTRAL AND SOUTHERN MTNS. CAA...PRESSURE CHANGES...AND SUBSIDENCE RELAX BETWEEN 15Z-18Z...WILL RUN ADVISORIES THROUGH WED MORNING. MESOETA AND RUC SHOW THAT ISENTROPIC LIFT AHEAD OF THE FRONTS WILL INCREASE THIS EVENING AND TONIGHT AS LLVL WIND FIELDS STRENGTHEN. RADAR TRENDS ARE SHOWING A SLOW CREEP IN THE PRECIP MASS OVER TN AND AL/GA TO THE EAST. MODELS KEEP THE BEST DYNAMICS TO THE NORTH OF THE FA TONIGHT. WITH INSTABILITY REMAINING WEAK WILL EXPECT THAT THE PRECIP WILL REMAIN IN THE MTNS UNTIL THE FRONTS APPROACH. WILL LEAVE CATE POPS IN THE MTNS AND WILL REDUCE POPS TO THE EAST BASED ON THE LATEST ETA AND GFS. ALTHOUGH NO THUNDER HAS OCCURRED IN THE CWA THIS EVENING...I BELIEVE THAT THE LIFT ALONG THE COLD FRONT WITH SLIGHT INCREASE IN INSTABILITY MAY YIELD ISO TS OVER THE WESTERN HALF OF THE FA. OTHERWISE...WILL MAKE SLIGHT CHANGES TO THE T/TD FIELDS. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 202 PM EST TUE NOV 30 2004 SHORT TERM (TONIGHT THROUGH FRIDAY)... ETA AND GFS ARE IN REASONABLE AGREEMENT WITH THE TIMING AND STRENGTH OF THE FRONT THAT CROSSES THE CWFA LATE TNGT. THEY BOTH RAPIDLY LIFT THE STRONG SHORT WAVE CURRENTLY OVER THE SRN PLAINS INTO THE NEW ENGLAND STATES BY EARLY WED AFTN. ETA LLVL FRONTOGENESIS IS QUITE STRONG OVER ERN TN AND NRN GA BY 0600 UTC TNGT...THOUGH IT WEAKENS SOME AS THE FRONT HITS THE MTNS. THEREFORE...EVEN THOUGH BEST DEEP LAYER FORCING IN THE FORM OF DPVA AND UPPER DIVERGENCE LIFTS TO OUR NE...THINK THAT LLVL FORCING WL BE SUFFICIENT TO CARRY A GOOD FRONTAL BAND RAPIDLY ACROSS MOST OF THE CWFA BETWEEN 0600 AND 1200 UTC WED. WITH THIS IN MIND...POPS WL BE MUCH CLOSER TO THE WETTER GFS TNGT AND EARLY WED. 1200 UTC UPPER AIR DID SHOW A NICE THERMAL/MOISTURE RIDGE EXTENDING INTO MIDDLE TN...WHERE CONVECTION IS CURRENTLY FOUND...SO WE MAY YET SEE SOME ELEVATED CONVECTION IN THE MTNS OVERNIGHT. HOWEVER... CONSIDERING LIMITED INSTABILITY AND LACK OF STRONG DEEP LAYER FORCING...WL LOWER THUNDER PROBABILITIES BACK TO SLIGHT CHANCE OVERNIGHT AND ONLY INCLUDE THE SLIGHT CHANCE MENTION IN THE MTNS IN THE ZONES. LATEST MODEL RUNS ARE NOT AS STRONG W/CAA BEHIND THE FRONT WED...AND 6 TO 12 HR PRESSURE RISES ARE NOT VERY IMPRESSIVE EITHER. THEREFORE DO NOT EXPECT MUCH IN THE WAY OF WIND PROBLEMS. LATER SHIFTS STILL MIGHT NEED A WIND ADVISORY FOR THE NRN MTNS...BUT THATS ABOUT IT. REST OF THE SHORT RANGE LOOKS GOOD. DWPTS REALLY LOWER WED NGHT AND THU...AND EXPECT THAT WE WILL SEE SOME VERY LOW HUMIDITY VALUES IN THE MTNS AND FOOTHILLS. HOWEVER...WET FUELS SHOULD PRECLUDE ANY FIRE WEATHER CONCERNS. THERE IS SOME QUESTION ABOUT HOW COLD WE GET ON THU MORNING. LOWERED MIN TEMPS 3-4 DEG...WHICH PUTS MINS SQUARELY IN LINE WITH A BLEND OF THE MET/MAV. LLVL WAA DOES PICK UP LATE...AND RIDGE TOPS MAY VERIFY QUITE A BIT WARMER THAN THE VALLEYS. LONG TERM (FRIDAY NIGHT THROUGH TUESDAY)... THE WESTERN CAROLINAS WILL BE TRAPPED BETWEEN ACTIVE NRN AND SRN STREAMS OVER THE WEEKEND. SHORT WAVE ENERGY PASSING BY TO THE NORTH ON SATURDAY WILL BRING A BRIEF SHOT OF FORCING...MOISTURE...AND NW FLOW TO THE NORTHERN MOUNTAINS. THICKNESS IN 850-700MB LAYER IS AROUND 1520M AND 850MB TEMPS MINUS 6. HAVE ADDED A SLIGHT CHANCE OF SNOW SHOWERS TO HANDLE THIS. OTHERWISE...HAVE REMOVED SLIGHT CHANCE POP OVER THE WEEKEND AND MADE MINOR ADJUSTMENTS TO TEMPS. EARLY PART OF THE WEEK BECOMES MORE ACTIVE AS SURFACE HIGH SLIDES OFF THE COAST AND MOISTURE STARTS TO RETURN. GFS MIGHT BE A BIT TOO FAST WITH DEVELOPING PRECIP SUNDAY NIGHT BUT IS SUPPORTED BY CANADIAN...SO CHANCE POP WILL BE EXPANDED ACROSS ENTIRE FORECAST AREA. CHANCE POP IS KEPT IN FOR REMAINDER OF MEDIUM RANGE PERIOD AS UPPER TROF AND JET AXIS REMAIN TO WEST AND NORTH PROVIDING PERIODIC SHOTS OF FORCING. MONDAY HIGH TEMP WAS NUDGED DOWNWARD TO TREND TOWARD COOLER MEX GUIDANCE. AVIATION... MVFR CEILING HAS ALREADY MOVED INTO NE GA AND WRN CAROLINAS AT 17Z...REACHING KAND AND KAVL...AND SHOULD CONTINUE TO DEVELOP EASTWARD THIS AFTERNOON AS LOW LEVEL ISENTROPIC UPGLIDE STRENGTHENS. THE EXCEPTION MIGHT BE KCLT WHERE CEILING IS KEPT IN THE LOW PART OF VFR THROUGH THE EARLY EVENING...BUT EVEN KCLT SHOULD BE MVFR BY 04Z. THE LATEST GFS SEEMS TO HAVE A DECENT HANDLE ON PRECIP SO FAR...AND THIS MODEL IS FOLLOWED FAIRLY CLOSELY. MVFR VISIBILITY IN RAIN SHOULD DEVELOP DURING THE EARLY MORNING HOURS AND PREVAIL UNTIL THE COLD FRONT SWEEPS THROUGH IN THE MORNING. CONDITIONS SHOULD IMPROVE RAPIDLY TO VFR BEHIND THE FRONT WEDNESDAY MORNING WITH A WIND SHIFT TO W OR NW...ALTHO KAVL WILL LIKELY KEEP LOW CLOUDINESS INTO THE AFTERNOON. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...WIND ADVISORY FOR ZONES NCZ033-049-050 TONIGHT THROUGH WEDNESDAY MORNING. ...LAKE WIND ADVISORY FOR ZONES NCZ048-051>053-058-059- 062>065 TONIGHT AND WEDNESDAY MORNING. SC...NONE. && $$ SHORT TERM (UPDATE)...NED sc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MORRISTOWN TN 950 PM EST TUE NOV 30 2004 .DISCUSSION...A REPORT OF STRONG WINDS IN MONROE COUNTY LED TO MAKING A FEW CALLS TO THE HIGHER TERRAIN AREAS...AND APPEARS THAT WIND SPEEDS MAY BE JUST UP TO WIND ADVISORY CRITERIA AT THIS POINT. SO...THINK IT IS WISE TO ISSUE A WIND ADVISORY FOR THE MTN ZONES THROUGH 4AM EST (09Z). RUC MODEL SHOWS LOW LEVEL JET MAXING OUT AT 50 TO 60 KNOTS OVER MY REGION AT 06Z WED...THEN STRONGEST WINDS MOVE EAST OF MY REGION BY 09-12Z. KMRX VAD WIND PROFILE HAS SHOWN THE 50 KNOT WINDS LOWERING TO THE 5000 FT LEVEL. THANKS TO GSP FOR CHAT COORDINATION. STEADY STREAM OF MOISTURE BEING TRANSPORTED NORTHEAST FROM THE WESTERN GULF OF MEXICO THIS EVENING...AHEAD OF THE SLOW MOVING UPPER LEVEL TROUGH WORKING EAST INTO THE MID MISS VALLEY. AREA WSR-88D RADARS SHOW A LARGE AREA OF LIGHT TO MODERATE RAIN FROM AL NE THRU WRN HALF OF TN INTO THE CENTRAL APPALACHIANS. A FEW BRIEF PERIODS OF +RA NOTED AT TIMES...BUT GENERALLY OUR FORECAST AREA HAS REMAINED BELOW HOURLY FLASH FLOOD GUIDANCE VALUES PER FFMP. HEAVIEST RAINS SO FAR NOTED OVER OUR CUMBERLAND PLATEAU COUNTIES WEST INTO OHX AREA...BUT CALLS MADE HAVE ONLY REVEALED MINOR PONDING OF WATER ON ROADWAYS. LATEST HOURLY RAINFALL RATES...WHERE HEAVIER RAINS ARE NOTED...ARE AVERAGING ONLY 0.15 TO 0.33 OF AN INCH. SURFACE BASED LIFTED INDICES SHOW STABLE AIRMASS...AND NOT MUCH IN THE WAY OF ELEVATED INSTABILITY INDICATED EITHER. ALTHOUGH...THERE HAVE BEEN ISOLATED LIGHTNING STRIKES NOTED THIS EVENING...SO MAY KEEP A SLIGHT CHANCE OF THUNDERSTORMS OVERNIGHT. 100 PERCENT RAIN CHANCE LOOKS GOOD OVERNIGHT...BUT MAY NEED TO FRESHEN THE ZONES JUST A BIT TO REFLECT A GRADUAL WIND SHIFT AS THE COLD FRONT EASES EASTWARD. COLD AIR ARRIVES JUST AS THE RAIN ENDS... SO WON'T WORRY ABOUT WINTRY PRECIPITATION AT THIS POINT...ALTHO A FEW FLURRIES MIGHT OCCUR IN THE HIGHEST TERRAIN WEDNESDAY MORNING. WILL FRESHEN THE ZFP...GRIDS AND WEB PRODUCTS BY OR AFTER 10PM EST. && .MRX WATCHES/WARNINGS/ADVISORIES... NC...WIND ADVISORY THRU 4AM EST FOR CHEROKEE AND CLAY COUNTIES. TN...WIND ADVISORY THRU 4AM EST FOR EXTREME EASTERN COUNTIES. VA...NONE. && $$ TG tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CORPUS CHRISTI TX 845 PM CST TUE NOV 30 2004 .DISCUSSION...KDRT SOUNDING THIS EVENING VERY DRY WITH PRECIPITABLE WATER AROUND 0.15 INCHES. CLEAR SKIES AND LIGHT WINDS WILL MAKE FOR STRONG RADIATIONAL COOLING TONIGHT ESPECIALLY IN THE NORTHWEST. NORMALLY IF THINGS HAVE NOT BEEN SO WARM AND KEEPING THE GROUND WARM FREEZE TO THE NORTHWEST WOULD BE OBVIOUS...BUT THAT IS NOT THE CASE THIS TIME. STILL KCOT TEMPERATURE HAS DROPPED TO AS LOW AS 44F BEFORE 830 PM TONIGHT WITH DEWPOINTS REMAINING IN THE UPPER 20S AND THINK THAT SOME LOCATIONS OVER THE NORTHWEST COULD SEE A FREEZE FOR A COUPLE OF HOURS TONIGHT DESPITE THE WARM GROUND. WILL ISSUE A FREEZE WARNING FOR MCMULLEN AND LASALLE COUNTIES BUT WILL HOLD OFF FURTHER NORTH AND EAST WHERE THE DEWPOINTS ARE UP. HIGH IS FORECAST TO BE RIGHT OVER THIS AREA AND THINK THERE WILL BE ENOUGH RADIATIONAL COOLING TO RESULT IN A FREEZE. ALSO...LATEST RUC WAS A FEW DEGREES TOO WARM OVER THIS AREA. OTHERWISE...QUITE COLD NIGHT AND HAVE ONLY ADJUSTED TEMPS UP TO THE NORTH...WHERE LIGHT FREEZE IS POSSIBLE LOWER AREAS. OTHERWISE...WILL JUST MAKE SOME MINOR ADJUSTMENTS TO THE INLAND GRIDS. && .MARINE...WAVES HAVE COME DOWN SHARPLY OVER THE GULFMEX WITH HEIGHTS FALLING TO 8 FEET AT BOUYS 020 AND 019. WILL KEEP SCA GOING FOR THE GULFMEX BUT WINDS HAVE DIED DOWN SUFFICIENTLY FOR NO FLAGS ON THE BAYS. BORDERLINE SCEC/SCA FOR THE NEARSHORE AS SEAS MAY BE NEAR 7 FEET NEAR 20NM. WILL GO WITH SCEC FOR THE NEARSHORE AS FEEL OVERALL WAVES ARE BELOW 7 FEET. && .AVIATION...SURFACE ANTICYCLONE CRESTS ACROSS THE REGION THROUGH 16Z WEDNESDAY WITH VFR CONDITIONS PREVAILING. SURFACE ANTICYCLONE THEN MOVES EAST AND ALLOWS A WARM THERMAL ADVECTION PATTERN TO DEVELOP WITH CEILINGS AOA 10000 FT THROUGH 00Z THURSDAY. && .CRP WATCHES/WARNINGS/ADVISORIES... FREEZE WARNING LASALLE AND MCMULLEN COUNTIES TONIGHT. SMALL CRAFT ADVISORY GMZ270-275. && $$ 86/GW...GRIDS/TEXT 85/BB...AVIATION/SHORT-TERM tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 330 AM EST WED DEC 1 2004 ...COOLER TEMPERATURES ON THE WAY... .SHORT TERM...FRONTAL BOUNDARY CURRENTLY LOCATED FROM NE GA TO FL PANHANDLE EXPECTED TO PUSH EWD INTO THE CWA TODAY WITH VERY LITTLE IN THE WAY OF SUFFICIENT LIFT TO GENERATE MORE THAN 20% POPS. LATEST RADAR TRENDS SUGGEST THIS SCENARIO AS DOES LATEST GUIDANCE FROM ETA GFS AND THE RUC. THUS HAVE LOWERED POPS TO 20% N OF A OCALA TO ST AUGUSTINE LINE TODAY. NARROW LINE OF SHOWER ACTIVITY EXPECTED TO PUSH INTO SRN ZONES TONIGHT BEFORE RAPIDLY DISSIPATING AND MOVING S WITH THE FRONT. HIGH PRESSURE RIDGE BUILDS IN FROM THE NW TONIGHT BUT BY THU HIGH PRES WEAKENS AS ANOTHER FRONT PASSES WELL TO OUR N OVER THE TN VALLEY. HIGH PRES BUILDS IN AGAIN FOR FRI WITH TEMPS TO REMAIN COOL AS THICKNESSES FALL SLIGHTLY. TEMP FORECAST IS TRICKY BUT HAVE GENERALLY USED A BLEND OF ETA AND GFS FOR NOW. CURRENT TREND FOR TODAY AT LEAST SUGGESTS GFS IS TOO COOL FOR MAX TEMPS. .LONG TERM...SAT-TUE. THE FRONT SAGS S INTO S FL OR THE FL STRAITS BUT WORKS NWD OVER THE WEEKEND AS 5H TROUGH DEEPENS OVER TX AND LOWER MS VALLEY AREAS AND 5H RIDGE BUILDS OVER S FL AND BAHAMAS. ISENTROPIC LIFT APPEARS TO BEGIN TO AFFECT THE FORECAST AREA SAT NIGHT. HAVE LOWERED POPS FOR SAT TO ACCOUNT FOR CONSISTENCY IN GFS LAST 2 RUNS TO SLOW DOWN THE MOISTURE RETURN...AND INCREASED POPS SLIGHTLY FOR SUN PER LATEST GUIDANCE BUT MAY NEED TO BE INCREASED IN LATER SHIFTS BASED ON WIDESPREAD AREA OF ISENTROPIC LIFT AND FAIRLY IMPRESSIVE 700 MB OMEGA PROGS. OTHERWISE...NO OTHER CHANGES MADE IN THE EXTENDED FORECAST. && .MARINE...COLD FRONT MOVES THROUGH THE COASTAL WATERS THIS AFTERNOON. HAVE GONE WITH AN EXERCISE CAUTION FOR THE OFFSHORE WATERS. FRONT WILL BE WEAKENING WHEN IT MOVES THROUGH...SO NOT EXPECTING ANYTHING MORE THAN A FEW SHOWERS AND A WIND SHIFT INTO THE NW. WINDS QUICKLY VEER AND LIGHTEN THURSDAY AS THE SURFACE HIGH BUILDS IN AND WEAKENS...THEN SHIFT INTO THE NORTH AGAIN AND INCREASE TO EXERCISE CAUTION THURSDAY NIGHT AND FRIDAY AS DRY REINFORCING FRONT PUSHES THROUGH. && .FIRE WX...NO CONCERNS TODAY. RELATIVE HUMIDITIES FALLING BRIEFLY TO CRITICAL LEVELS WELL INLAND THURSDAY BUT NOT LOW ENOUGH TO WARRANT ANY WATCHES FOR NOW. && .PRELIMINARY POINT TEMPS/POPS... AMG 63 38 67 41 / 20 00 00 00 SSI 68 47 66 49 / 20 00 00 00 JAX 70 44 69 45 / 20 00 00 00 SGJ 72 52 70 49 / 20 10 00 10 GNV 71 44 70 45 / 20 10 00 00 OCF 74 47 72 47 / 10 20 00 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. && $$ ARS/PP fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 357 AM EST WED DEC 01 2004 .DISCUSSION... SFC FRONT CURRENTLY LIES ACROSS LAKE SUPERIOR...WITH NNE WINDS AT THE NORTHERN C-MANS AND A S TO W WIND ACROSS UPPER MICHIGAN (INCLUDING A WLY WIND STILL AT CMX). THOUGH CLOUD COVER IS BECOMING MORE WIDESPREAD OVER THE LAKE...SHSN HAVE YET TO DEVELOP ON THE KEWEENAW (850MB TEMPS ONLY -2C PER THE RUC AT 08Z). AS SHORTWAVE IN NORTHERN ONTARIO PUSHES EAST TODAY...FRONT WILL CONTINUE TO SAG ACROSS THE U P...BRINGING COLDER AIR AND INCREASING CHANCES OF LAKE EFFECT SHSN AS THE DAY PROGRESSES. MAIN FORECAST CONCERN IN THE SHORT TERM IS POTENTIAL FOR LES TODAY THRU THU NIGHT. H8 TEMPS FALL TO AT LEAST -12C IN THE NW CWA THIS AFTN (PER RUC/ETA AND GFS...THOUGH THE GFS IS A BIT COLDER). ETA/GFS SEEM TO HAVE INITIALIZED FAIRLY WELL LOOKING UPSTREAM...AND WITHOUT A KINL SOUNDING AT 00Z...ITS TOUGH TO TELL WHICH WILL BE CORRECT. THAT BEING SAID...THERE IS SUFFICIENTLY COLD AIR NOT TOO FAR TO OUR NORTH...AND SAT IMAGERY/SFC OBS SHOW ABUNDANT LOW CIGS AND -SHSN FROM JUST N OF LAKE SUPERIOR THRU NWRN MN ON THE BACK SIDE OF THE FRONT. SHOULD CERTAINLY BE ENOUGH MOISTURE/INSTABILITY TO GENERATE LAKE EFFECT LATER ON. CONVERGENCE WILL BE FOCUSED IN NWRN PARTS INITIALLY...AND WILL KEEP WITH 1-3 INCHES OUT THERE. WILL CUT BACK ACCUMS IN THE EAST TO ONLY AN INCH TOPS TODAY AS BLYR TEMPS LOOK TO REMAIN TOO WARM FOR MUCH SNOW GROWTH UNTIL AFTER 18Z. BASED ON LACK OF SNOW YET ON THE KEWEENAW THIS SEEMS TO BE THE WAY TO GO. SUSTAINED LIKELY POPS TONIGHT IN NW WIND FAVORED AREAS...BUT INCREASING SUBSIDENCE IN THE WAKE OF THE SHORTWAVE LOWER INVERSION HEIGHTS FROM 5-6KFT TO 3-4KFT OVERNIGHT. WILL GIVE 1-3 INCHES BUT WOULD EXPECT BRUNT OF THAT TO FALL IN THE EVENING (LINGERING LONGEST IN THE EAST). THU/THU NIGHT ARE STILL TRICKY. NEXT SHORTWAVE WILL DROP OUT OF NWRN CANADA AND TRACK A SFC LOW/TROF IN OUR VICINITY AS IT COMES THRU. STILL LIKE THE GFS/UKMET IDEA OF MORE OF A SFC REFLECTION THAN THE ETA...BUT THE ETA SEEMS TO BE COMING IN LINE GRADUALLY. AS THE SHORTWAVE NEARS...00Z GFS/UKMET RUNS INDICATED WINDS WILL BACK SUFFICIENTLY ON THU TO DIMINISH LES EVERYWHERE BUT PERHAPS ON THE KEWEENAW. HOWEVER...THE WAVE ITSELF AND ASSOCIATED MODERATE H8-H5 Q-VECTOR CONVERGENCE WARRANT AT LEAST CHANCE POPS EVERYWHERE...EVEN WITHOUT LAKE HELP. WILL BE INTERESTING TO SEE WHERE SFC CONVERGENCE SETS UP...BUT CURRENT MODEL RUNS SHOW A RATHER CHAOTIC WIND PATTERN AS THE TROF COMES THRU...WHICH WOULD SUGGEST NOTHING TOO ORGANIZED AS FAR AS LES GOES. THAT BEING SAID...WILL KEEP WITH A PERIOD OF LIKELY POPS NEAR LAKE SUPERIOR AS THE SFC TROF COMES THRU...AND THERE IS STILL TOO MUCH UNCERTAINTY (MODELS HAVE BEEN VERY INCONSISTENT) TO DISCOUNT AN ADVY EVENT SOMEWHERE. REGARDING SNOW ACCUMS...WILL PAINT 2-4 INCHES IN THE WEST THU (GREATEST ON KEWEENAW WHERE CONVERGENCE MAY PERSIST LONGEST) AND 1-2 TO THE EAST...WITH ANOTHER 2 OR SO THU EVNG AS THE TROF DEPARTS. FORECAST OF DIMINISHING LES LATE THU NIGHT...THEN INCREASING CHANCES OF SYNOPTIC SNOW FRI/FRI EVENING STILL LOOKS ON TRACK. IN FACT... WITH SLY BLYR WINDS AND LINGERING INSTABILITY OVER LAKE MICHIGAN (DELTA-TS ON THE ORDER OF 15C)...WILL HAVE TO WATCH FOR ENHANCEMENT INTO SOUTHERN SCHOOLCRAFT CTY. GFS BUFKIT SOUNDINGS SHOW A MOIST PROFILE THRU INVERSION HEIGHT NEAR 750MB...AND LIFT COINCIDING WITH FAVORABLE SNOW GROWTH TEMPERATURES. WILL HAVE TO WATCH THIS. THIS WAVE WILL EMERGE FROM THE GULF OF ALASKA AND WILL BRING SOME PACIFIC AIR WITH IT...BUT AS IT DEPARTS MODELS DIVERGE A GREAT DEAL. ETA ACTUALLY TAPS INTO SOME OF THE ARCTIC AIR TO OUR NORTH AS EARLY AS FRI NIGHT (NOT SUPPORTED BY ANY OTHER MODEL). INTO EARLY NEXT WEEK...SFC RIDGE UNDER CONFLUENCE ALF WILL SET UP SOMEWHERE TO OUR NORTH. UKMET/CANADIAN SUGGEST MUCH COLDER AIR OVER THE UPPER GREAT LAKES THAN THE GFS...WHICH CONTINUES TO SHOW A WARM FRONT LIFTING NORTH OF LAKE SUPERIOR. MANY QUESTIONS YET TO BE RESOLVED...AND MUCH UNCERTAINTY EXISTS INTO NEXT WEEK. HAVE MADE NO CHANGES TO THE EXTENDED. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JKL mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO 327 AM CST WED DEC 1 2004 .DISCUSSION... DECEMBER ENTERED QUIETLY THIS MORNING. HAVE NOT HAD TO MAKE MANY CHANGES TO ONGOING FORECAST. WINDS HAVE NOT DECOUPLED...SO TEMPERATURES ARE NOT HITTING ROCK BOTTOM AS THEY COULD HAVE WITH CLEAR SKIES AND FRESH SNOWCOVER. WESTERLY WINDS WILL CONTINUE TODAY...AND TEMPERATURES WILL RISE INTO THE 40S. GUIDANCE CONSENSUS WOULD SUGGEST RAISING HIGHS TODAY A COUPLE OF DEGREES...BUT FEEL THAT WITH SNOW ON THE GROUND, THE SUBLIMATION OR MELTING WILL KEEP TEMPS FROM BEING A CATEGORY HIGHER THAN FORECAST. SHORTWAVE WITH ASSOCIATED WEAK COLD FRONT GOES THROUGH OVERNIGHT...WHICH WILL PUT HIGHS ONLY A COUPLE OF DEGREES COOLER ON THURSDAY. ANOTHER RIPPLE TO GO THROUGH ON FRIDAY WITH MINIMAL IMPACT ON FORECAST. THE NEXT SENSIBLE WEATHER MAKER WILL BE TOWARDS THE END OF THE WEEKEND. THE CRITICAL TEMPERATURE LINE IS STILL WAVERING AROUND NORTHERN MISSOURI...SO HAVE NOT CHANGED WEATHER TYPE FROM PREVIOUS. HAVE NOT CHANGED POPS EITHER. SYSTEM MAY BE MOISTURE DEPRIVED BY THE TIME IT GETS HERE. LVQ && .PREV DISCUSSION... 955 PM TUE... LAST VESTIGES OF SNOW MOVING OUT OF CFWA ATTM AN HAVE UPDATED GRIDS TO INDICATE SNOW THREAT HAS ENDED. BACK EDGE OF MID-LEVEL CLOUDS ABOUT HALF WAY ACROSS MISSOURI...AND SHOULD CLEAR EASTERN FRINGES OF CFWA SHORTLY AFTER MIDNIGHT. WEST WINDS OF PLENTY OF BOUNDARY LAYER MOISTURE WILL KEEP TEMPERATURES FROM FALLING OFF TOO RAPIDLY. TWEAKED GOING FORECAST MINS SLIGHTLY...BUT SEEMED REASONABLE BASED ON CURRENT TEMPERATURE AND DEWPOINT TRENDS. SF 300 PM TUE... THE CENTER OF THE ELONGATED UPPER LOW RESPONSIBLE FOR OUR SNOW TODAY IS NEARLY ON TOP OF KANSAS CITY ACCORDING TO RUC ANALYSIS AT 20 UTC. POSITIVE VORTICITY ADVECTION FOR THE REMAINDER OF THE AFTERNOON AND EVENING WILL BE OVER NORTH CENTRAL AND NORTHEAST MISSOURI. DESPITE NUMEROUS SLOW MOVING BANDS OF LIGHT TO OCCASIONALLY MODERATE SNOW OVER KANSAS CITY TODAY, MOST AREAS MEASURED JUST AN INCH OR SO. WARM GROUND MELTED MUCH OF THE SNOW AS IT FELL, AND ACCUMULATIONS WERE GENERALLY RESTRICTED TO GRASSY SURFACES. I'M NOT EXPECTING ACCUMULATIONS EAST OF KANSAS CITY TO BE ANY MORE SIGNIFICANT THROUGH THIS EVENING. VISIBLE SATELLITE IMAGERY SHOWS THAT THE CHANGE FROM SNOW TO MOSTLY CLEAR SKIES IS PRETTY ABRUPT. THE NORTHWEST TIP OF MISSOURI IS EXPERIENCING SUNSHINE WHILE THE KANSAS CITY AREA HAS VISIBILITIES OF LESS THAN A MILE AND SNOW. KOCH THE LAST HALF OF THE FORECAST WILL START OUT DRY AS KANSAS AND MISSOURI LANGUISH IN BETWEEN WINTERY STORM SYSTEMS. LATE THIS WORK WEEK TEMPERATURES WILL REMAIN COOL...RUNNING AT OR JUST BELOW NORMAL AS NORTHWEST WINDS SLOWLY BECOME WESTERLY. BY THIS WEEKEND TEMPERATURES ARE EXPECTED TO REBOUND ABOVE NORMAL AS SOUTHERLY WINDS RETURNED TO THE REGION AHEAD OF THE NEXT SHORTWAVE EJECTING OUT OF THE DESERT SOUTHWEST. LATEST RUNS OF THE GFS HAVE SLOWED THE PROGRESSION OF THE SHORTWAVE OUT OF THE SOUTHWEST...WHICH HAS BROUGHT IT MORE IN LINE WITH THE ECMWF AND CANADIAN MODELS. STILL SOME QUESTION OF WHETHER THE SYSTEM WILL REMAIN AN OPEN WAVE...AS CURRENTLY FORECAST...OR IF LATER RUNS WILL CLOSE IT OFF SLOWING IT DOWN EVEN MORE. ANYWAY...LEFT GOING FORECAST MOSTLY UNCHANGED EXCEPT FOR TWO SMALL DETAILS. ONE...I STRETCHED OUT THE CHANCE OF PRECIP INTO MONDAY NIGHT DUE TO THE SLOWING OF THE MODEL SOLUTIONS...AND TWO I ADDED A MIX OF RAIN AND/OR SNOW TO THE NORTHERN TIER OF COUNTIES FOR PERIODS WHEN THE TEMPERATURES LOOKED TO WARRANT IT. CUTTER && .EAX WATCHES/WARNINGS/ADVISORIES... KS...NONE MO...NONE $$ WFO EAX mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 323 AM EST WED DEC 1 2004 .SHORT TERM (TODAY THROUGH THURSDAY NIGHT)... LOW PRESSURE WAS MOVING ACROSS THE AREA THIS MORNING. ON THE BACKSIDE OF THE LOW...WINDS WERE QUITE GUSTY. GUSTS 30 TO 40 MPH WILL BE COMMON THIS MORNING...WITH THE HIGHEST CURRENT OBS STILL UNDER ADVISORY CRITERIA...BEFORE WINDING DOWN INTO THE AFTERNOON. THERE IS SOME WRAP AROUND PCPN BEHIND THE LOW AS WELL...WITH SNOW ACROSS CENTRAL INDIANA AND NORTHWARD. APPLYING P-TYPE METHODS TO THE RUC..ETA...GFS AND LOOKING AT THE CURRENT OBS TO THE WEST...THE CONSENSUS IS THAT A BRIEF SNOW SNOW/MIX WILL WORK WEST TO EAST ACROSS MOST OF THE AREA EARLY THIS MORNING. THIS WILL INCLUDE DAYTON...CINCINNATI...AND EVENTUALLY COLUMBUS. THEN..ETA TIME HEIGHT PROFILES SHOW A VERY DRY AIR MASS WITH STRONG SUBSIDENCE WORKING IN QUICKLY BEHIND A TRAILING UPPER TROF. THIS FEATURE APPEARS TO BE COINCIDENT WITH THE CURRENT CLEARING LINE...PROGGED TO PASS ACROSS THE AREA WEST TO EAST MID TO LATE MORNING. WITH THIS IN MIND...IT APPEARS THAT TEMPERATURES WILL FALL A BIT FROM EARLY TEMPS THROUGH THE MORNING BEFORE REBOUNDING SLIGHTLY INTO THE LOW TO MID 40S THIS AFTERNOON WITH THE CLEARING. AFTER MOSTLY CLEAR SKIES TONIGHT...A S/W MOVES QUICKLY ACROSS THE REGION THURSDAY AFTERNOON INTO THE OVERNIGHT. THE NEW MAV GUIDANCE GIVES SLIGHT CHANCE POPS FOR THIS TIME PERIOD..AND LIFT IS INDICATED ON APPROPRIATE GFS ISENTROPIC SFC(S) WITH LOW SAT PR DEF(S)...MORE PRONOUNCED IN THE NORTH. ETA TIME HEIGHT PROFILES SHOW AN INCREASE IN LOW LEVEL MOISTURE AS WELL...BUT MET POPS ARE LOWER. AT THIS POINT...WILL LEAVE SNOW SHOWERS/FLURRIES OUT OF THURSDAY NIGHT PENDING THE NEXT MODEL RUNS. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 1248 AM EST WED DEC 1 2004 AVIATION (06Z-06Z)... WINDS STARTING TO VEER AND STRENGTHEN AS THE SURFACE LOW CONTINUES TO TRACK INTO NORTHERN OHIO. WRAP AROUND PRECIPITATION IS STARTING TO COME BACK INTO THE WESTERN PART OF THE AREA ALREADY. EXPECT THIS TO PRIMARILY BE RAIN. BUT COULD SEE A BRIEF PERIOD OF A MIX OR JUST SNOW ON THE BACK EDGE AFFECTING DAYTON AND COLUMBUS TERMINALS. THERE WILL BE SOME MVFR RESTRICTIONS TO VISIBILITY. BUT THE MAIN CONCERN ARE THE CEILINGS AND THE GUSTY WINDS. EXPECT A SLIGHT RISE IN CLOUD HEIGHTS WITH TIME BUT OVERALL STAYING THE IFR-MVFR RANGE. LOOKS LIKE A FAIRLY SHARP CLEARING LINE WILL MOVE ACROSS THE REGION BETWEEN 15Z AND 18Z DUE TO STRONG SUBSIDENCE AND DRYING ON THE BACK SIDE OF THE SYSTEM. STRONGEST WINDS ARE EXPECTED THIS MORNING WITH THE GRADIENT RELAXING DURING THE AFTERNOON AS THE LOW QUICKLY MOVES OFF TO THE NORTHEAST. THE FOLLOWING WAS ORIGINALLY ISSUED AT 300 PM EST TUE NOV 30 2004 LONG TERM (FRIDAY THROUGH TUESDAY)... GFS/ECMWF ARE IN FAIRLY GOOD AGREEMENT FOR THE EXTENDED FCST...AND THUS HAVE USED. REGION WILL CONTINUE TO BE UNDER A NWLY UPR LVL FLOW PATTERN THROUGH THE WEEKEND...THEN THE FLOW WILL BUCKLE TO THE SW AS NEXT MAJOR SYSTEM IS EXPECTED LATE MONDAY INTO TUESDAY. OTHERWISE...A CLIPPER TYPE SYSTEM WILL SWEEP THROUGH THE AREA LATE FRIDAY NIGHT INTO THE FIRST PART OF SATURDAY. AT THIS POINT...WILL INTRODUCE 30 TO 40 PERCENT CHC/S OF PCPN. PCPN SHOULD START OUT AS SNOW FRIDAY NIGHT INTO SATURDAY MORNING...THEN IT MAY MIX WITH RAIN BEFORE ENDING. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION ON SUNDAY. AS MENTIONED BEFORE...NEXT SIGNIFICANT SYSTEM WILL MOVE THROUGH THE REGION TUESDAY/TUESDAY NIGHT. INCREASING WAA AHEAD OF THE COLD FRONT/UPR LVL LOW WILL BRING A CHC OF SHOWERS ON MONDAY...CONTINUING INTO TUESDAY. TEMPS WILL BE BELOW NORMAL VALUES FRIDAY AND SATURDAY...THEN THEY WILL REBOUND TO SLIGHTLY ABOVE NORMAL READINGS MONDAY INTO TUESDAY DUE TO WAA AHEAD OF SYSTEM. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. IN...NONE. KY...NONE. && $$ oh AREA FORECAST DISCUSSION UPDATE NATIONAL WEATHER SERVICE CLEVELAND OHIO 1145 PM EST TUE NOV 30 2004 .AVIATION (06Z-06Z)... DEEPENING LOW PRES NEAR THE OH BORDER JUST W OF DAY WL MOVE NE ACRS THE CWA PASSING THRU BTW FDY AND MFD MOVG TO ERN END LERI BY 12Z. GNLY IFR CONDS ACRS WRN AND SRN PTN ATTM WL SPREAD ACRS THE REST AREA BY 08Z. EXPECT PREDOM IFR CONDS IN THE W WITH ERN AREAS LKLY LOW MVFR OCNL IFR COND TIL FEW HRS AFTER LOW MOVS E OF TAF SITE. CIGS WILL THEN GRDLY IMP MVFR CONDS THEN TO VFR MID MRNG W ERY AFTN E. PCPN WL MIX WITH OR CHNG TO SNOW FOR BRF PD THEN PCPN SHUD END...AGAIN MID MRNG W TO ERY AFTN FAR E. VERY DRY AIR MOVG IN BHND LOW SKIES CLEAR OR LEAST GO SCT LATTER PART OF THE FCST. && .SHORT TERM UPDATE EARLY OUTPUT FROM THE ETA 00Z RUN INDICATES LOW WILL TRACK TO THE NORTH TOWARD TOLEDO AND THEN MAKE THE RIGHT TURN UP LAKE ERIE. CURRENT SURFACE OBSERVATIONS INDICATE LOW CENTER IS OVER SOUTHEAST INDIANA AND THIS IS RIGHT ON TRACK WITH 00Z ETA TRACK. THE LOW HAS BEEN WOBBLING SLIGHTLY AS IT TRACKS NORTH. THE AXIS OF GREATEST PRESSURE FALLS EXTENDS NORTH FROM THE LOW CENTER INTO TOLEDO WITH ANOTHER AXIS TO THE EAST OVER COLUMBUS. LOW SHOULD TRACK AS ETA PROJECTS AS HIGH PRESSURE ON THE EAST COAST BEGINS TO SHIFT OUT TO SEA. RAIN WILL CONTINUE TO LIFT NORTH WITH A BREAK FOR A PERIOD OF TIME IN THE ACTIVITY. THEN AS LOW MOVES NORTHEAST...WE WILL SEE A WRAP AROUND PRECIPITATION BAND MOVE INTO THE AREA. ETA 850 MB TO 1000 MB THICKNESS FROM CURRENT 00Z RUN INDICATES RAIN SHOULD BECOME MIXED WITH OR CHANGE TO SNOW IN THE WESTERN PORTIONS OF THE FORECAST AREA AROUND 12Z IN THE MORNING. REST OF THE AREA SHOULD SEE RAIN BECOMING MIXED WITH SNOW THROUGH THE MORNING HOURS. WILL SEND AN UPDATE TO ADJUST WINDS IN THE TEXT BASED ON CURRENT FORECAST TRACK OF THE LOW. WILL HAVE TO KEEP AN EYE ON WINDS FOR WEDNESDAY AS GRADIENT TIGHTENS UP AND LOW DEEPENS WITH TIME. .PREVIOUS SHORT TERM (TNGT THRU THURS) LRG AREA OF RN MOVG INTO THE OH VLY. RN ASSOCD WI A DVLPG AND DEEPENG LOW. RUC/ETA HAVE THE TRACK OF THE LOW FURTHER W MOVG INTO WRN LERI WHILE THE GFS, THE FAVORED MODEL HERE, CURVG NE THRU NE OH INTO WRN NY BY WED MRNG. AS A RESULT THE WINDS WL BE TURNG INTO THE SW/W THEN NW SOONER RATHER THAN LATER AND INCRASG RPDLY. WDSPRD RN SHIELD ACOMPANYS THIS LOW AND A PUSH OF WRM AIR AHD OF THE LOW WL HOLD UP TEMPS IN THE 35-40 RANGE BFR THE COLDER AIR RUSHES IN VIA THE NW FLOW ON THE BACKSIDE AFT THE PASS OF THE LOW WED. SOME RESIDUAL MSTR LEFT OVR WED MRNG MAY SEE A RN/SNW MIX AND PERHAPS ALL SNW FOR A BRF PD WED MRNG. DRY SLOT WORKS IN WED AFTN AND INTO THE NGT OVR ALL BUT THE NE. CULD BE SOME LK EFFECT CLDS/PCPN AND IN THE FORM OF SNW AS TEMPS DROP INTO THE 20S BY THURS MRNG. A FAIR WX PATERN SETS UP WI WK HI BLDG IN FRM THE S SHUOLD KEEP MST AREAS DRY. .LONG TERM (FRI-WED) AS THE HI EXITS TO THE E FRI, ANOTHER CDFNT DROPS DWN AND CROSSES THE AREA FRI NGT INTO SAT. TEMPS TO BE COLD ENUF FOR SCT SNSH AND PERHAPS LK ENHANCED IN THE NE ON SAT. A CHG IN THE JET TO A MORE ZONAL AND SW FLOW INTO ERY NXT WEEK MAY PUSH TEMPS INTO THE 40S AND EVEN LWR 50S BY WED. && .CLE WATCHES/WARNINGS/ADVISORIES. OH...GALE LERI. PA...GALE LERI. && SHORT TERM UPDATE...LOMBARDY SHORT TERM...20 LONG TERM...20 AVIATION...WCR && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE EASTERN ND/GRAND FORKS ND 1013 AM CST WED DEC 1 2004 .DISCUSSION...UPDATE CONCERNS REVOLVE AROUND TEMPERATURES AND -SN CHANCES FOR THE REMAINDER OF THE DAY. 15Z SURFACE ANALYSIS SHOWS COLD FRONT FROM A KMOT-KJMS LINE WITH ENTIRE FORECAST AREA (FA) IN LOW STRATUS DECK BEHIND FRONT. SCT FLURRIES CONTINUE IN COLD AIR MASS WITH HIGH LOW LEVEL MOISTURE. QUICK LOOK AT 12Z RUC/ETA/GFS SHOW ALL TO INITIALIZE WELL AND IN GOOD AGREEMENT FOR TODAY. WEAK SFC HIGH PRESSURE WILL PROPAGATE THROUGH FA TODAY. STRONG LOW LEVEL COLD AIR ADVECTION WILL CONTINUE THROUGH THE MORNING HOURS WITH NEAR STEADY TEMPERATURES AS A RESULT. AS HIGH SLIDES THROUGH EXPECT 950MB TEMPERATURES TO REBOUND A BIT...ALLOWING FOR 3F-4F RECOVERY. WITH THIS THINKING...CURRENT TEMPERATURES...AND CLOUD COVER IN PLACE WILL NEED TO LOWER MAX VALUES TODAY. THERE MAY BE A COUPLE BREAKS IN CLOUD COVER ACROSS NW MN AS DRY LOW LEVEL AIR ATTEMPTS TO WORK SOUTH (EVIDENT ON SATELLITE IMAGERY)...BUT ANY SOLAR SHOULD NOT AFFECT TEMPERATURES TOO MUCH WITH CONVECTIVE TEMPERATURE IN THE LOW TEENS. NEXT CONCERN IS -SN CHANCES FOR THE DEVILS LAKE AREA. AREA OF -SN ON KMBX RADAR PROPAGATING SE TOWARD FA. THIS ASSOCIATED WITH WARM AIR ADVECTION...925MB-850MB FRONTOGENESIS. AS HIGH SLIDES EAST EXPECT THIS FORCING TO AFFECT THE DEVILS LAKE AREA. LOW LEVEL MOISTURE WILL BE PRESENT...WILL NEED TO ADD LIGHT SNOW MENTION TODAY FOR DEVILS LAKE AREA WITH ACCUMULATIONS UNDER ONE INCH. FLURRIES MENTION FOR REMAINDER OF FA STILL LOOKS GOOD. OTHER ASPECTS OF FORECAST REMAIN ON TRACK. UPDATE TO BE ISSUED BY 1045AM. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ GRAFENAUER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 845 AM EST WED DEC 1 2004 .SHORT TERM... CLOUDS CLEARING RAPIDLY FROM WEST TO EAST. WILL UPDATE SOON TO REMOVE PRECIP AND SHOW CLRG TREND. SHLD BE LITTLE OR NO CU REFORMING. WILL LEAVE TEMPS ALONE FOR NOW. WINDS WILL DIMINISH BUT STAY IN THE BRISK CATEGORY. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ISSUED AT 645 AM EST WED DEC 1 2004 .AVIATION (12Z-12Z)... RADAR SHOWS PRECIPITATION DIMINISHING QUICKLY ACROSS THE AREA. THIS PRECIPITATION HAS BEEN CHANGING OVER TO SNOW BUT WITH THE WEAKENING TREND IT DOES NOT LOOK LIKE THIS WILL HAVE MUCH EFFECT ON CEILINGS OR VISIBILITIES. EXTRAPOLATION OF BACK EDGE OF CLOUDS WILL RESULT IN SKIES CLEARING AT ALL TERMINALS BY 15Z. THUS THE MAIN CONCERN WILL BE WINDS. STRONGEST MIXING IS CURRENTLY AFFECTING THE COLUMBUS AREA AND THIS SHOULD BE MOVING OFF TO THE EAST. GRADIENT WILL GRADUALLY WEAKEN AS THE DAY PROGRESSES ALLOWING WINDS TO SLOWLY SUBSIDE. EXPECT WIND DIRECTION TO REMAIN WEST UNTIL LATE IN THE DAY WHEN IT WILL BACK TO SOUTHWEST. OVERNIGHT LIGHT TO MODERATE SOUTHWEST WINDS WILL CONTINUE WITH JUST SOME CIRRUS. && SHORT TERM (TODAY THROUGH THURSDAY NIGHT)... LOW PRESSURE WAS MOVING ACROSS THE AREA THIS MORNING. ON THE BACKSIDE OF THE LOW...WINDS WERE QUITE GUSTY. GUSTS 30 TO 40 MPH WILL BE COMMON THIS MORNING...WITH THE HIGHEST CURRENT OBS STILL UNDER ADVISORY CRITERIA...BEFORE WINDING DOWN INTO THE AFTERNOON. THERE IS SOME WRAP AROUND PCPN BEHIND THE LOW AS WELL...WITH SNOW ACROSS CENTRAL INDIANA AND NORTHWARD. APPLYING P-TYPE METHODS TO THE RUC..ETA...GFS AND LOOKING AT THE CURRENT OBS TO THE WEST...THE CONSENSUS IS THAT A BRIEF SNOW SNOW/MIX WILL WORK WEST TO EAST ACROSS MOST OF THE AREA EARLY THIS MORNING. THIS WILL INCLUDE DAYTON...CINCINNATI...AND EVENTUALLY COLUMBUS. THEN..ETA TIME HEIGHT PROFILES SHOW A VERY DRY AIR MASS WITH STRONG SUBSIDENCE WORKING IN QUICKLY BEHIND A TRAILING UPPER TROF. THIS FEATURE APPEARS TO BE COINCIDENT WITH THE CURRENT CLEARING LINE...PROGGED TO PASS ACROSS THE AREA WEST TO EAST MID TO LATE MORNING. WITH THIS IN MIND...IT APPEARS THAT TEMPERATURES WILL FALL A BIT FROM EARLY TEMPS THROUGH THE MORNING BEFORE REBOUNDING SLIGHTLY INTO THE LOW TO MID 40S THIS AFTERNOON WITH THE CLEARING. AFTER MOSTLY CLEAR SKIES TONIGHT...A S/W MOVES QUICKLY ACROSS THE REGION THURSDAY AFTERNOON INTO THE OVERNIGHT. THE NEW MAV GUIDANCE GIVES SLIGHT CHANCE POPS FOR THIS TIME PERIOD..AND LIFT IS INDICATED ON APPROPRIATE GFS ISENTROPIC SFC(S) WITH LOW SAT PR DEF(S)...MORE PRONOUNCED IN THE NORTH. ETA TIME HEIGHT PROFILES SHOW AN INCREASE IN LOW LEVEL MOISTURE AS WELL...BUT MET POPS ARE LOWER. AT THIS POINT...WILL LEAVE SNOW SHOWERS/FLURRIES OUT OF THURSDAY NIGHT PENDING THE NEXT MODEL RUNS. THE FOLLOWING WAS ORIGINALLY ISSUED AT 300 PM EST TUE NOV 30 2004 LONG TERM (FRIDAY THROUGH TUESDAY)... GFS/ECMWF ARE IN FAIRLY GOOD AGREEMENT FOR THE EXTENDED FCST...AND THUS HAVE USED. REGION WILL CONTINUE TO BE UNDER A NWLY UPR LVL FLOW PATTERN THROUGH THE WEEKEND...THEN THE FLOW WILL BUCKLE TO THE SW AS NEXT MAJOR SYSTEM IS EXPECTED LATE MONDAY INTO TUESDAY. OTHERWISE...A CLIPPER TYPE SYSTEM WILL SWEEP THROUGH THE AREA LATE FRIDAY NIGHT INTO THE FIRST PART OF SATURDAY. AT THIS POINT...WILL INTRODUCE 30 TO 40 PERCENT CHC/S OF PCPN. PCPN SHOULD START OUT AS SNOW FRIDAY NIGHT INTO SATURDAY MORNING...THEN IT MAY MIX WITH RAIN BEFORE ENDING. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION ON SUNDAY. AS MENTIONED BEFORE...NEXT SIGNIFICANT SYSTEM WILL MOVE THROUGH THE REGION TUESDAY/TUESDAY NIGHT. INCREASING WAA AHEAD OF THE COLD FRONT/UPR LVL LOW WILL BRING A CHC OF SHOWERS ON MONDAY...CONTINUING INTO TUESDAY. TEMPS WILL BE BELOW NORMAL VALUES FRIDAY AND SATURDAY...THEN THEY WILL REBOUND TO SLIGHTLY ABOVE NORMAL READINGS MONDAY INTO TUESDAY DUE TO WAA AHEAD OF SYSTEM. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. IN...NONE. KY...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 635 AM EST WED DEC 1 2004 .AVIATION (12Z-12Z)... RADAR SHOWS PRECIPITATION DIMINISHING QUICKLY ACROSS THE AREA. THIS PRECIPITATION HAS BEEN CHANGING OVER TO SNOW BUT WITH THE WEAKENING TREND IT DOES NOT LOOK LIKE THIS WILL HAVE MUCH EFFECT ON CEILINGS OR VISIBILITIES. EXTRAPOLATION OF BACK EDGE OF CLOUDS WILL RESULT IN SKIES CLEARING AT ALL TERMINALS BY 15Z. THUS THE MAIN CONCERN WILL BE WINDS. STRONGEST MIXING IS CURRENTLY AFFECTING THE COLUMBUS AREA AND THIS SHOULD BE MOVING OFF TO THE EAST. GRADIENT WILL GRADUALLY WEAKEN AS THE DAY PROGRESSES ALLOWING WINDS TO SLOWLY SUBSIDE. EXPECT WIND DIRECTION TO REMAIN WEST UNTIL LATE IN THE DAY WHEN IT WILL BACK TO SOUTHWEST. OVERNIGHT LIGHT TO MODERATE SOUTHWEST WINDS WILL CONTINUE WITH JUST SOME CIRRUS. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ORIGINALLY ISSUED AT 323 AM EST WED DEC 1 2004 SHORT TERM (TODAY THROUGH THURSDAY NIGHT)... LOW PRESSURE WAS MOVING ACROSS THE AREA THIS MORNING. ON THE BACKSIDE OF THE LOW...WINDS WERE QUITE GUSTY. GUSTS 30 TO 40 MPH WILL BE COMMON THIS MORNING...WITH THE HIGHEST CURRENT OBS STILL UNDER ADVISORY CRITERIA...BEFORE WINDING DOWN INTO THE AFTERNOON. THERE IS SOME WRAP AROUND PCPN BEHIND THE LOW AS WELL...WITH SNOW ACROSS CENTRAL INDIANA AND NORTHWARD. APPLYING P-TYPE METHODS TO THE RUC..ETA...GFS AND LOOKING AT THE CURRENT OBS TO THE WEST...THE CONSENSUS IS THAT A BRIEF SNOW SNOW/MIX WILL WORK WEST TO EAST ACROSS MOST OF THE AREA EARLY THIS MORNING. THIS WILL INCLUDE DAYTON...CINCINNATI...AND EVENTUALLY COLUMBUS. THEN..ETA TIME HEIGHT PROFILES SHOW A VERY DRY AIR MASS WITH STRONG SUBSIDENCE WORKING IN QUICKLY BEHIND A TRAILING UPPER TROF. THIS FEATURE APPEARS TO BE COINCIDENT WITH THE CURRENT CLEARING LINE...PROGGED TO PASS ACROSS THE AREA WEST TO EAST MID TO LATE MORNING. WITH THIS IN MIND...IT APPEARS THAT TEMPERATURES WILL FALL A BIT FROM EARLY TEMPS THROUGH THE MORNING BEFORE REBOUNDING SLIGHTLY INTO THE LOW TO MID 40S THIS AFTERNOON WITH THE CLEARING. AFTER MOSTLY CLEAR SKIES TONIGHT...A S/W MOVES QUICKLY ACROSS THE REGION THURSDAY AFTERNOON INTO THE OVERNIGHT. THE NEW MAV GUIDANCE GIVES SLIGHT CHANCE POPS FOR THIS TIME PERIOD..AND LIFT IS INDICATED ON APPROPRIATE GFS ISENTROPIC SFC(S) WITH LOW SAT PR DEF(S)...MORE PRONOUNCED IN THE NORTH. ETA TIME HEIGHT PROFILES SHOW AN INCREASE IN LOW LEVEL MOISTURE AS WELL...BUT MET POPS ARE LOWER. AT THIS POINT...WILL LEAVE SNOW SHOWERS/FLURRIES OUT OF THURSDAY NIGHT PENDING THE NEXT MODEL RUNS. THE FOLLOWING WAS ORIGINALLY ISSUED AT 300 PM EST TUE NOV 30 2004 LONG TERM (FRIDAY THROUGH TUESDAY)... GFS/ECMWF ARE IN FAIRLY GOOD AGREEMENT FOR THE EXTENDED FCST...AND THUS HAVE USED. REGION WILL CONTINUE TO BE UNDER A NWLY UPR LVL FLOW PATTERN THROUGH THE WEEKEND...THEN THE FLOW WILL BUCKLE TO THE SW AS NEXT MAJOR SYSTEM IS EXPECTED LATE MONDAY INTO TUESDAY. OTHERWISE...A CLIPPER TYPE SYSTEM WILL SWEEP THROUGH THE AREA LATE FRIDAY NIGHT INTO THE FIRST PART OF SATURDAY. AT THIS POINT...WILL INTRODUCE 30 TO 40 PERCENT CHC/S OF PCPN. PCPN SHOULD START OUT AS SNOW FRIDAY NIGHT INTO SATURDAY MORNING...THEN IT MAY MIX WITH RAIN BEFORE ENDING. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION ON SUNDAY. AS MENTIONED BEFORE...NEXT SIGNIFICANT SYSTEM WILL MOVE THROUGH THE REGION TUESDAY/TUESDAY NIGHT. INCREASING WAA AHEAD OF THE COLD FRONT/UPR LVL LOW WILL BRING A CHC OF SHOWERS ON MONDAY...CONTINUING INTO TUESDAY. TEMPS WILL BE BELOW NORMAL VALUES FRIDAY AND SATURDAY...THEN THEY WILL REBOUND TO SLIGHTLY ABOVE NORMAL READINGS MONDAY INTO TUESDAY DUE TO WAA AHEAD OF SYSTEM. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. IN...NONE. KY...NONE. && $$ oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI ISSUED BY NATIONAL WEATHER SERVICE MARQUETTE MI 447 PM EST WED DEC 01 2004 .SHORT TERM... CURRENT WEATHER...20Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED A BROAD TROUGH OVER CENTRAL CANADA. SHRTWVS OF INTEREST WERE LOCATED IN THE NORTHWEST FLOW ON THE WEST SIDE OF THE TROUGH...WITH ONE OVER CENTRAL SASKATCHEWAN AND THE OTHER OVER THE GULF OF ALASKA. THE ONE OVER THE GULF OF ALASKA IS VERY IMPRESSIVE...WITH A DRY SPOT SURROUNDING BY UPPER LEVEL MOISTURE. AT THE SURFACE...AN ARCTIC COLD FRONT WAS LOCATED ALONG THE LAKE SUPERIOR/UPPER MICHIGAN SHORELINE. SATELLITE AND RADAR IMAGERY HAS SHOWN A FEW SNOW SHOWERS ALONG AND AHEAD OF THE FRONT. HOWEVER...EVEN A FEW SNOW SHOWERS HAVE DEVELOPED OFF OF LAKE MICHIGAN WHERE LAKE SURFACE TO 850MB DELTA-T HAS BEEN AROUND 13C (PER 12Z SOUNDINGS FROM GRB AND APX). TONIGHT...WITH THE ARCTIC FRONT MOVING SOUTH...EXPECT SNOW SHOWERS TO BE ON THE INCREASE ACROSS ALL OF EASTERN UPPER MI AND NORTHERN LOWER MICHIGAN. WEST TO NORTHWEST WINDS COMING OFF OF LAKES MICHIGAN AND SUPERIOR WILL ENHANCE THE SNOW AS 850MB TEMPS CONTINUE TO FALL THIS EVENING WITH THE PASSAGE OF THE ARCTIC FRONT. HOWEVER... ACCUMULATIONS SHOULD NOT BE ALL THAT MUCH DUE TO THIS FRONT LACKING MOISTURE. ONE TO TWO INCHES SEEMS REASONABLE WITH THE HEAVIEST SNOWFALL FROM THE STRAITS TO MANISTEE DUE TO THE LAKE ENHANCEMENT. WITH PLENTY OF CLOUDS AND SOMEWHAT BREEZY CONDITIONS...DO NOT EXPECT TEMPS TO FALL TOO QUICKLY. HAVE KEPT LOWS CLOSE TO MET GUIDANCE. THURSDAY...SHRTWV TROUGH OVER CENTRAL SASKATCHEWAN INDUCES A SURFACE LOW OVER MN THURSDAY MORNING AS IT MOVES TOWARDS THE WESTERN GREAT LAKES. DIFFERENCES ARISE WHAT WILL HAPPEN WITH THE SURFACE LOW AS THE SHRTWV DIGS INTO WISCONSIN. THE 12Z GFS RUN DOES NOT DEEPEN THIS SURFACE LOW WHEREAS THE ETA ALONG WITH PREVIOUS GFS RUNS DID. THE ETA ACTUALLY TRENDED TOWARD A DEEPER SCENARIO. HAVE FOLLOWED A COMPROMISE FOR THE PRESENT TIME. EXPECT THE SURFACE LOW TO MOVE TO THE BAY OF GREEN BAY BY 00Z FRI. STEEP MID LEVEL LAPSE RATES (ON THE ORDER OF 7.5 C/KM FROM 700-500MB) COMBINED WITH DPVA FROM THE SHRTWV WILL LEAD TO THE DEVELOPMENT OF SNOW AHEAD OF THE SURFACE LOW. WITH 850MB TEMPS STILL ON THE ORDER OF -10 TO -12C AND WINDS BACKING TO THE SOUTHWEST AHEAD OF THE LOW...EXPECT A BAND OF LAKE EFFECT TO FORM ON LAKE MICHIGAN. THIS BAND WILL MOVE INTO THE EASTERN UPPER MICHIGAN COUNTIES DURING THE AFTERNOON...POSSIBLY SCRAPING THE WESTERN NORTHERN LOWER MICHIGAN SHORELINE. HAVE PUT IN UP TO 3 INCHES GIVEN THE FAVORABLE LAKE ENHANCEMENT/DYNAMICS...BUT IF FUTURE RUNS LOOK LIKE THE ETA THE AMOUNTS MAY NEED TO BE HIGHER. HIGH TEMPS LOOK FINE. THURSDAY NIGHT...WARM ADVECTION SNOW WILL MOVE OUT AFTER MIDNIGHT WHILE LAKE EFFECT CONTINUES AS WINDS REMAIN WESTERLY AND 850MB TEMPS STRUGGLE TO WARM. BY 12Z...EXPECT A WEAK HIGH PRESSURE RIDGE TO MOVE OVER THE LOWER PENINSULA...HELPING TO LOWER THE INVERSION AND REDUCE THE AMOUNT OF LAKE EFFECT. ANOTHER INCH OR TWO IS POSSIBLE ALONG THE WESTERN NORTHERN LOWER MICHIGAN SHORELINE AND OVER THE EASTERN U.P....BUT AS STATED EARLIER...THESE AMOUNTS MAY NEED TO BE BUMPED UP. AGAIN...NO MAJOR CHANGES TO TEMPERATURES. FRIDAY...SHRTWV OVER THE GULF OF ALASKA MOVES DOWN INTO MN BY 12Z AND TO SOUTHERN WI BY 00Z. GIVEN THE IMPRESSIVE LOOK OF THIS SHRTWV...EXPECT TO SEE A SOMEWHAT DEEP SURFACE LOW TO MOVE THROUGH THE REGION...ALONG WITH SNOW AND BREEZY SOUTHWESTERLIES AHEAD OF IT. BOTH THE ETA AND THE GFS SHOW A 999MB LOW MOVING INTO UPPER MICHIGAN DURING THE DAY...WITH SURFACE WINDS INCREASING TO 15 TO 20 KT. 850MB TEMPERATURES ARE A LITTLE WARMER...-6 TO -8C...BUT WITH LAKE MICHIGAN TEMPERATURES OF 7-9C...EXPECT THE LAKE EFFECT TO CONTINUE. AGAIN IT LOOKS LIKE WESTERN PORTIONS OF MACKINAC AND CHIPPEWA COUNTIES WILL BE AFFECTED THE MOST DUE TO THE COMBINATION OF THE DYNAMICS AND LAKE ENHANCEMENT. HIGH TEMPERATURES WILL BE WARMER THAN THURSDAY DUE TO THE WARM ADVECTION. HAVE KEPT HIGHS CLOSE TO MET GUIDANCE. FRIDAY NIGHT...THE GULF OF ALASKA SHRTWV IS PROGGED TO MOVE THROUGH THE WESTERN GREAT LAKES PRETTY QUICK...SO ANY WARM ADVECTION SNOW WILL NOT ACCUMULATE MUCH. IN FACT...BY 06Z ALL OF LOWER MICHIGAN IS UNDER STRONG SUBSIDENCE AS SHRTWV RIDGING MOVES IN. WEST WINDS WILL KEEP THE LAKE EFFECT GOING...BUT WITH THE WINDS BRINGING IN WARMER AIR (UP TO -2C AT 850MB AT 12Z SAT PER ETA/GFS)...EXPECTING THE LAKE EFFECT TO BE ON A DIMINISHING TREND THROUGH THE NIGHT. WITH THE WARM AIR ADVECTION...BREEZY CONDITIONS AND CLOUD COVER...TEMPERATURES WILL NOT FALL MUCH. TEMPS IN THE MID 20S LOOK GOOD. .LONG TERM... SAT-WED...ALTHOUGH BEST FORCING WITH THE NRN STREAM SHRTWV REMAINS WELL NORTH OF THE AREA SATURDAY...ISENTROPIC LIFT WITH WAA REGIME TO THE SOUTH MAY BE ENOUGH TO SQUEEZE OUT SOME LIGHT SNOW SHOWERS/SPRINKLES. MAIN FOCUS DURING THIS PERIOD CONTINUES TO BE POTENTIAL STORM HEADING INTO THE GREAT LAKES EARLY NEXT WEEK. AFTER SEVERAL DAYS OF NRN STREAM SHORTWAVES AFFECTING THE AREA DURING THE WEEK... SRN STREAM AMPLIFICATION OVER THE ROCKIES DURING THE WEEKEND WILL LEAD TO ONE OR MORE SHORTWAVES LIFTING NE EARLY NEXT WEEK WITH THE MORE SIGNIFICANT SFC LOW MOVING INTO THE GREAT LAKES IN THE MON NIGHT/TUE TIME FRAME. GFS/ECWMF SHOW DECENT CONTINUITY WITH PREVIOUS RUNS. 144HR MAPS FROM CANADIAN/UKMET LEND SOME SUPPORT NOW...BUT IT SHOULD BE NOTED THAT BOTH OF THESE MODELS ALSO INDICATE STRONGER CONFLUENCE AND SFC HIGH PRES EXTENDING ACROSS ONTARIO. THE IMPLICATION HERE IS THAT SRN STREAM WAVE MAY BE FORCED FAR ENOUGH S TO KEEP PCPN SHIELD AND RAIN/SNOW LINE FARTHER SOUTH. ON THE OTHER HAND...GFS (INCLUDING ENSEMBLE MEAN) CONTINUES TO LIFT SYSTEM FAR ENOUGH N TO RESULT IN WIDESPREAD PCPN AS WELL AS PTYPE ISSUES. 00Z ECMWF HAS BACKED OFF A BIT ON CONSOLIDATED SFC LOW IT HAD IN PREVIOUS RUNS OVER UPPER LAKES TUE. IT NOW BRINGS A WEAKER LEAD WAVE INTO THE WRN GREAT LAKES MON WITH MAIN SHORTWAVE IN QUESTION NOW HEADING FARTHER E INTO THE ERN LAKES. THE POINT OF ALL THIS DISCUSSION IS THAT THERE IS CONSIDERABLE UNCERTAINTY IN HOW THINGS WILL PLAY OUT EARLY NEXT WEEK. FOR NOW...WILL FOLLOW HPC DISCUSSION/PROGS CLOSELY WHICH BASICALLY RESULTS IN LITTLE CHANGE TO GOING FCST FOR EARLY NEXT WEEK. && .APX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ AJ (SHORT TERM)...ROLFSON/JLB (LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 419 PM EST WED DEC 1 2004 .DISCUSSION... COMPLICATED FCST EXPECTED OVER THE NEXT FEW DAYS AS A SERIES OF DISTURBANCES SLIDE SE ACROSS THE AREA. MAIN FCST CONCERNS WILL REVOLVE AROUND LES AND LAKE ENHANCEMENT POTENTIAL WITH EACH WAVE. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW BROAD CYCLONIC FLOW COVERING MUCH OF THE CONUS WITH 2 STREAMS EVIDENT. SHORTWAVES ARE MORE DEFINED IN THE SRN STREAM WITH ONE STRONG SYSTEM LIFTING THRU NEW ENGLAND...ANOTHER WAS OVER THE SRN ROCKIES WITH A THIRD DROPPING THRU NRN NV/CA. IN THE NRN STREAM...ONE SHORTWAVE WAS MOVING E OF LAKE SUPERIOR WITH SEVERAL MORE UPSTREAM. MOST PROMINENT WAVE WAS OVER THE GULF OF ALASKA...AND THIS SYSTEM WILL REACH THE WRN LAKES ON FRI. SHORTWAVE E OF LAKE SUPERIOR HAS HELPED PUSH COLD FRONT S ACROSS LAKE SUPERIOR AND INTO UPPER MI TODAY. IT IS VERY COLD N OF THE FRONT WITH TEMPS BARELY ABOVE 10F ACROSS THE LAKE RIGHT NOW. AT 12Z...850MB TEMPS RANGED FROM -13C AT KINL TO -20C AT CWPL AND CYQD...AND THE SOUNDINGS AT KINL/CWPL SHOWED MOIST LOW-MID LEVELS. DECENT SHSN ACCOMPANIED FRONT INTO UPPER MI WITH VSBYS OCCASIONALLY AS LOW AS 1/2SM ON THE KEWEENAW EARLIER IN THE DAY. KMQT RADAR SHOWS INCREASING COVERAGE AND INTENSITY OF LES (REFLECTIVITIES REACHING 28DBZ MORE FREQUENTLY) ACROSS SCNTRL LAKE SUPERIOR INTO BARAGA/MARQUETTE AND ALGER COUNTIES AS CAA CONTINUES. ETA/GFS HAVE INITIALIZED 850MB TEMPS WELL...AND DIFFERENCES BETWEEN THE MODELS ARE MINOR. HOWEVER...SINCE GFS LOOKS TO BE SLIGHTLY BETTER ON WRN EXTENT OF COLD AIR AS NOTED ON CYQD SOUNDING...WILL UTILIZE ITS 850MB TEMPS OVER THE NEXT 36-48HRS. SHORTWAVE CURRENTLY OVER SRN MANITOBA BRUSHES NRN LAKE SUPERIOR LATE THIS EVENING...AND WITH 850MB TEMPS DROPPING TO -15C AND ADEQUATE LOW-MID LEVEL MOISTURE PER KINL/CWPL SOUNDINGS...EXPECT WIDESPREAD COVERAGE OF LES IN NW LOW-LEVEL FLOW TONIGHT. ETA/GFS FCST SOUNDINGS SHOW INVERSIONS DROPPING FROM ABOUT 7KFT TO 5KFT AFTER SHORTWAVE PASSES. INSTABILITY AND INVERSION HEIGHTS SUGGEST ACCUMULATIONS WILL BE ON THE ORDER OF 2-4 INCHES IN MOST AREAS WITH SOME 5 INCH AMOUNTS LOCALLY. SINCE ETA SHOWS BEST 950MB CONVERGENCE EXTENDING FROM NRN ONTONAGON/HOUGHTON COUNTIES TO PICTURED ROCKS WILL HIGHLIGHT BEST SNOW ACCUMULATIONS IN THAT AREA. ON THU...ATTENTION TURNS TO NEXT SHORTWAVE THAT DROPS INTO THE WRN LAKES BY 00Z. IT WILL BE A COMPLICATED FCST WITH LAKE ENHANCEMENT POTENTIALLY OFF BOTH LAKE SUPERIOR AND LAKE MICHIGAN. PREVIOUS RUNS OF THE GFS SHOWED A SMALL CLOSED CIRCULATION IN THE SFC WIND FIELD AS SHORTWAVE PASSED THRU THE REGION WHILE ETA DID NOT. 12Z GFS DOES NOT SHOW THAT NOW...BUT ETA DOES. BELIEVE THERE WILL BE A SFC REFLECTION AS SHORTWAVE PASSES GIVEN INSTABILITY OVER THE LAKE (LAKE-850MB DELTA-T 16-20C)...MAYBE NOT A CLOSED CIRCULATION...BUT AT LEAST SIGNIFICANT SHARPENING OF THE SFC TROFFING OVER UPPER MI/SRN LAKE SUPERIOR. ETA/GFS ACTUALLY SHOW IMPRESSIVE 700MB UPWARD MOTION AND DECENT LOW-MID LEVEL QVECTOR CONVERGENCE AS SHORTWAVE MOVES ACROSS THE AREA. SO LAKE ENHANCEMENT COULD BE QUITE SIGNIFICANT. THE PROBLEM ARISES WITH WHERE CONVERGENCE WILL SET UP. THE LOW-LEVEL WIND MAY BACK SUFFICIENTLY TO PUSH LES OFFSHORE MOST AREAS THU MORNING WITH EXCEPTION OF THE KEWEENAW. WOULD THEN EXPECT PROBABLY ALL AREAS NEAR THE LAKE TO RECEIVE A PERIOD OF HEAVIER SNOW AT SOME POINT LATE THU AFTN/EVENING AS SFC TROF MOVES S AND ONSHORE ACROSS THE REST OF FCST AREA. CURRENT THINKING IS THAT AN ADVY WILL PROBABLY BE NEEDED...ESPECIALLY GIVEN THE INSTABILITY AND SYNOPTIC ENHANCEMENT...BUT AT THIS POINT...IT IS DIFFICULT TO PIN DOWN THE LOCATION. FOR NOW...WILL GO WITH HIGHEST ACCUMULATIONS (UP TO 5 INCHES) OVER THE KEWEENAW...AND 1-3 OVER THE REST OF THE LAKE SUPERIOR COUNTIES...LEAST FROM MARQUETTE E AS IT MAY BE LATE IN THE DAY BEFORE LAKE ENHANCED SNOW MOVES BACK ON SHORE. THERE IS ALSO A POSSIBILITY THAT IF WINDS BACK ENOUGH THU PER ETA...LAKE ENHANCEMENT OFF LAKE MICHIGAN COULD BECOME AN ISSUE IN SCHOOLCRAFT/LUCE COUNTIES. THIS WILL NEED TO BE WATCHED CLOSELY AS A FEW HRS OF HVY SNOW IS NOT OUT OF THE QUESTION. LOCAL HIGH RES WSETA SUGGESTS THIS WILL OCCUR LATE AFTN/EARLY EVENING. TO COVER POTENTIAL...WILL PAINT A COUPLE OF INCHES OF ADDITIONAL ACCUMULATION IN THAT AREA LATE THU/THU EVENING. INLAND AREAS...EXPECT SOME -SN WITH ACCUMULATIONS UP TO AN INCH. LES WILL WIND DOWN/END FROM W TO E BY FRI MORNING AS WINDS BACK AHEAD OF NEXT SHORTWAVE DROPPING TOWARD THE WRN LAKES. THIS SHORTWAVE LOOKS QUITE IMPRESSIVE RIGHT NOW IN THE GULF OF ALASKA. EXPECT A PERIOD OF SNOW TO SPREAD ACROSS THE FCST AREA FRI. WITH 285K SFC SHOWING MIXING RATIO OF ABOUT 2G/KG AVBL AND LIFT TO LAST MAYBE 6HRS...EXPECT MOST AREAS TO SEE AN INCH MAYBE TWO OF ACCUMULATION. LAKE ENHANCMENT OFF LAKE MICHIGAN IN SW FLOW IS A GOOD BET...AND HAVE ADDED ANOTHER INCH OR TWO ACROSS SCHOOLCRAFT/LUCE COUNTIES... COULD BE MORE. PACIFIC AIR FLOODS IN BEHIND SYSTEM...SO NOT EXPECTING ANY LES IN THE WAKE OF SHORTWAVE. HOWEVER...ANOTHER SHORTWAVE FOLLOWING QUICKLY WILL CONTINUE THE CHC OF -SN FRI NIGHT INTO SAT. SUN-WED...MAIN FOCUS DURING THIS PERIOD CONTINUES TO BE POTENTIAL STORM HEADING INTO THE GREAT LAKES EARLY NEXT WEEK. AFTER SEVERAL DAYS OF NRN STREAM SHORTWAVES AFFECTING THE AREA DURING THE WEEK... SRN STREAM AMPLIFICATION OVER THE ROCKIES DURING THE WEEKEND WILL LEAD TO AT LEAST 2 SHORTWAVES LIFTING NE EARLY NEXT WEEK WITH THE MORE SIGNIFICANT SFC LOW MOVING INTO THE GREAT LAKES IN THE MON NIGHT/TUE TIME FRAME. GFS/ECWMF SHOW DECENT CONTINUITY WITH PREVIOUS RUNS. 144HR MAPS FROM CANADIAN/UKMET LEND SOME SUPPORT NOW...BUT THESE MODELS ALSO INDICATE STRONGER CONFLUENCE AND SFC HIGH PRES EXTENDING ACROSS ONTARIO. THE IMPLICATION HERE IS THAT SRN STREAM WAVE MAY BE FORCED FAR ENOUGH S TO LIMIT IMPACT HERE. ON THE OTHER HAND...GFS (INCLUDING ENSEMBLE MEAN) CONTINUES TO LIFT SYSTEM FAR ENOUGH N TO RESULT IN WIDESPREAD PCPN AS WELL AS PTYPE ISSUES. 00Z ECMWF BACKED OFF A BIT ON THE CONSOLIDATED SFC LOW IT HAD IN PREVIOUS RUNS OVER THE UPPER LAKES TUE...BUT NEWLY ARRIVED 12Z ECMWF IS BACK ON BOARD WITH A STRONG SFC LOW LIFTING INTO LWR MI. SO THERE IS STILL CONSIDERABLE UNCERTAINTY IN HOW THINGS WILL PLAY OUT EARLY NEXT WEEK. FOR NOW...WILL FOLLOW HPC DISCUSSION/PROGS CLOSELY WHICH BASICALLY RESULTS IN LITTLE CHANGE TO GOING FCST FOR EARLY NEXT WEEK. HAVE DOUBTS WHETHER PCPN WILL BREAK OUT AS SOON AS SUN AFTN IN WAA REGIME...BUT WILL MAINTAIN LOW POPS GIVEN GFS RUN-TO-RUN CONTINUITY. WITH IDEA OF SFC LOW MOVING INTO NRN LWR MI/ERN UPPER MI BY TUE MORNING...WILL CONTINUE WITH RAIN/SNOW WORDING SCNTRL/E AND SNOW W MON INTO EARLY TUE WITH TRANSITION TO ALL SNOW TUE. DECENT LES AND/OR LAKE ENHANCED EVENT MAY TAKE SHAPE LATER TUE INTO WED WITH MID/UPPER TROF OVER THE GREAT LAKES AND CAA DROPPING 850MB TEMPS INTO THE -15 TO -20C RANGE. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 115 PM EST WED DEC 1 2004 .AVIATION (18Z-18Z)... ONLY FCST ISSUE IS WINDS. DIMINISHING TREND. SOME HIGH CLOUDS AHEAD OF NEXT WEAK SYSTEM WILL MOVE IN LATE TONIGHT AND THU. WINDS BECOMING SOUTHWEST AND LIGHT TONIGHT. && .PREVIOUS DISCUSSION... THE FOLLOWING WAS ISSUED AT 845 AM EST WED DEC 1 2004 .SHORT TERM... CLOUDS CLEARING RAPIDLY FROM WEST TO EAST. WILL UPDATE SOON TO REMOVE PRECIP AND SHOW CLRG TREND. SHLD BE LITTLE OR NO CU REFORMING. WILL LEAVE TEMPS ALONE FOR NOW. WINDS WILL DIMINISH BUT STAY IN THE BRISK CATEGORY. && .AVIATION (12Z-12Z)... RADAR SHOWS PRECIPITATION DIMINISHING QUICKLY ACROSS THE AREA. THIS PRECIPITATION HAS BEEN CHANGING OVER TO SNOW BUT WITH THE WEAKENING TREND IT DOES NOT LOOK LIKE THIS WILL HAVE MUCH EFFECT ON CEILINGS OR VISIBILITIES. EXTRAPOLATION OF BACK EDGE OF CLOUDS WILL RESULT IN SKIES CLEARING AT ALL TERMINALS BY 15Z. THUS THE MAIN CONCERN WILL BE WINDS. STRONGEST MIXING IS CURRENTLY AFFECTING THE COLUMBUS AREA AND THIS SHOULD BE MOVING OFF TO THE EAST. GRADIENT WILL GRADUALLY WEAKEN AS THE DAY PROGRESSES ALLOWING WINDS TO SLOWLY SUBSIDE. EXPECT WIND DIRECTION TO REMAIN WEST UNTIL LATE IN THE DAY WHEN IT WILL BACK TO SOUTHWEST. OVERNIGHT LIGHT TO MODERATE SOUTHWEST WINDS WILL CONTINUE WITH JUST SOME CIRRUS. && SHORT TERM (TODAY THROUGH THURSDAY NIGHT)... LOW PRESSURE WAS MOVING ACROSS THE AREA THIS MORNING. ON THE BACKSIDE OF THE LOW...WINDS WERE QUITE GUSTY. GUSTS 30 TO 40 MPH WILL BE COMMON THIS MORNING...WITH THE HIGHEST CURRENT OBS STILL UNDER ADVISORY CRITERIA...BEFORE WINDING DOWN INTO THE AFTERNOON. THERE IS SOME WRAP AROUND PCPN BEHIND THE LOW AS WELL...WITH SNOW ACROSS CENTRAL INDIANA AND NORTHWARD. APPLYING P-TYPE METHODS TO THE RUC..ETA...GFS AND LOOKING AT THE CURRENT OBS TO THE WEST...THE CONSENSUS IS THAT A BRIEF SNOW SNOW/MIX WILL WORK WEST TO EAST ACROSS MOST OF THE AREA EARLY THIS MORNING. THIS WILL INCLUDE DAYTON...CINCINNATI...AND EVENTUALLY COLUMBUS. THEN..ETA TIME HEIGHT PROFILES SHOW A VERY DRY AIR MASS WITH STRONG SUBSIDENCE WORKING IN QUICKLY BEHIND A TRAILING UPPER TROF. THIS FEATURE APPEARS TO BE COINCIDENT WITH THE CURRENT CLEARING LINE...PROGGED TO PASS ACROSS THE AREA WEST TO EAST MID TO LATE MORNING. WITH THIS IN MIND...IT APPEARS THAT TEMPERATURES WILL FALL A BIT FROM EARLY TEMPS THROUGH THE MORNING BEFORE REBOUNDING SLIGHTLY INTO THE LOW TO MID 40S THIS AFTERNOON WITH THE CLEARING. AFTER MOSTLY CLEAR SKIES TONIGHT...A S/W MOVES QUICKLY ACROSS THE REGION THURSDAY AFTERNOON INTO THE OVERNIGHT. THE NEW MAV GUIDANCE GIVES SLIGHT CHANCE POPS FOR THIS TIME PERIOD..AND LIFT IS INDICATED ON APPROPRIATE GFS ISENTROPIC SFC(S) WITH LOW SAT PR DEF(S)...MORE PRONOUNCED IN THE NORTH. ETA TIME HEIGHT PROFILES SHOW AN INCREASE IN LOW LEVEL MOISTURE AS WELL...BUT MET POPS ARE LOWER. AT THIS POINT...WILL LEAVE SNOW SHOWERS/FLURRIES OUT OF THURSDAY NIGHT PENDING THE NEXT MODEL RUNS. THE FOLLOWING WAS ORIGINALLY ISSUED AT 300 PM EST TUE NOV 30 2004 LONG TERM (FRIDAY THROUGH TUESDAY)... GFS/ECMWF ARE IN FAIRLY GOOD AGREEMENT FOR THE EXTENDED FCST...AND THUS HAVE USED. REGION WILL CONTINUE TO BE UNDER A NWLY UPR LVL FLOW PATTERN THROUGH THE WEEKEND...THEN THE FLOW WILL BUCKLE TO THE SW AS NEXT MAJOR SYSTEM IS EXPECTED LATE MONDAY INTO TUESDAY. OTHERWISE...A CLIPPER TYPE SYSTEM WILL SWEEP THROUGH THE AREA LATE FRIDAY NIGHT INTO THE FIRST PART OF SATURDAY. AT THIS POINT...WILL INTRODUCE 30 TO 40 PERCENT CHC/S OF PCPN. PCPN SHOULD START OUT AS SNOW FRIDAY NIGHT INTO SATURDAY MORNING...THEN IT MAY MIX WITH RAIN BEFORE ENDING. A RIDGE OF HIGH PRESSURE WILL BUILD INTO THE REGION ON SUNDAY. AS MENTIONED BEFORE...NEXT SIGNIFICANT SYSTEM WILL MOVE THROUGH THE REGION TUESDAY/TUESDAY NIGHT. INCREASING WAA AHEAD OF THE COLD FRONT/UPR LVL LOW WILL BRING A CHC OF SHOWERS ON MONDAY...CONTINUING INTO TUESDAY. TEMPS WILL BE BELOW NORMAL VALUES FRIDAY AND SATURDAY...THEN THEY WILL REBOUND TO SLIGHTLY ABOVE NORMAL READINGS MONDAY INTO TUESDAY DUE TO WAA AHEAD OF SYSTEM. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. IN...NONE. KY...NONE. && $$ oh