AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 915 PM EDT SUN OCT 2 2005 .UPDATED... QUICK UPDATE TO REMOVE POPS FOR THE REST OF THE NIGHT. ONLY MINOR ADJUSTMENT PLANNED TO TEMPS AND WINDS. && .PREVIOUS FORECAST... UPPER LEVEL RIDGING ALOFT CONTINUES TO PROVIDE EASTERLY FLOW OVER FORECAST AREA THROUGH SHORT TERM PERIODS. SURFACE HIGH PRESSURE OFF THE NEW ENGLAND COAST WILL STRENGTH AS IT SHIFTS EASTWARD THROUGH WEDNESDAY...INCREASING ATLANTIC MOISTURE AS WEAK WAVES MOVE ACROSS FORECAST AREA TONIGHT AND THEN AGAIN TOMORROW EVENING. GOOD MOISTURE WILL CONTINUE TO PROVIDE PARTLY TO MOSTLY CLOUDY SKIES THROUGH THE SHORT TERM WITH LITTLE INSTABILITY NOTED. TEMPERATURES WILL CONTINUE TO TREND TOWARD COOLER NORMAL VALUES ALTHOUGH EXPECT THEM TO REMAIN A DEGREE OR TWO WARMER THAN NORMAL. WEAKENING UPPER LEVEL RIDGING WILL KEEP SHORT WAVE MOVING OUT OF PACIFIC NORTHWEST ON TUESDAY NORTH OF FORECAST AREA AS IT MOVES ACROSS THE UPPER PLAINS ON WEDNESDAY AND GREAT LAKES AREA ON THURSDAY. GFS INDICATING SURFACE FRONT ASSOCIATED WITH SHORT WAVE WILL PUSH THROUGH FORECAST AREA LATE WEDNESDAY NIGHT EARLY THURSDAY... HOWEVER WITH MUCH OF THE UPPER LEVEL SUPPORT NORTH OF AREA ONLY SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED. GFS CONTINUES TO SHOW DRIER AIR IS SLOW TO PUSH INTO FORECAST AREA AND WILL CONTINUE TO RAISE TEMPERATURES DAY 6 AND 7 AS COLDEST AIR REMAINS NORTH OF FORECAST AREA. && .AVIATION... OVERALL PATTERN OF THE PAST COUPLE OF DAYS REMAINS IN PLACE. UPPER AND SURFACE HIGH TO THE NORTHEAST OF THE REGION WITH TROPICAL LOW EASTERN GULF/CUBA AREA. NO SIGNIFICANT CHANGE TO PATTERN FORECAST THROUGH MONDAY. AS THE TROPICAL LOW BEGINS TO DRIFT WEST ON THE SOUTH SIDE OF THE SUBTROPICAL HIGH DURING THE WEEK...A FEEDER BAND OF DEEP TROPICAL MOISTURE WILL BE PULLED NORTHWARD ACROSS THE AREA. AT THIS POINT...THIS SHOULD NOT HAVE A SIGNIFICANT IMPACT ON THE AREA UNTIL AT LEAST WEDNESDAY. UNTIL THEN...LITTLE DAY-TO-DAY CHANGE. CEILINGS...VERY GOOD CU/TCU FIELD OBSERVED THIS AFTERNOON WITH DEEP EASTERLY/TROPICAL AIR MASS IN PLACE. SUFFICIENT INSTABILITY AND MOISTURE TO ALLOW FOR A FEW SHOWERS IN THE ATL AREA...WITH ISOLATED THUNDERSTORMS SE OF MCN. SOME MID/HIGH CLOUD DEBRIS WILL BE LEFT OVER THE AREA FROM CONVECTION TO THE SOUTH THROUGH THE EVENING. CONDITIONS DO NOT APPEAR TO BE AS FAVORABLE FOR LOW CLOUD DEVELOPMENT MONDAY MORNING AS THEY HAVE BEEN. GFS AND RUC NOT REALLY ADVERTISING DEVELOPMENT OF EARLY MORNING LOW CLOUDS...HOWEVER ETA IS. MOST AREAS SHOULD HAVE VFR CIGS THROUGH EARLY MORNING...THEN MVFR AT WORST FOR THE EARLY MORNING HOURS. THIS WILL PROBABLY BEST BE HANDLED VIA A TEMPO GROUP GIVEN CURRENT UNCERTAINTY. VISIBILITY...WITH LESS LOW CLOUDINESS EXPECTED OVERNIGHT...REDUCTIONS TO VISIBILITY MAY BE MORE WIDESPREAD TONIGHT. MOST AREAS SHOULD REMAIN MVFR AT WORST...WITH THE POSSIBLE EXCEPTION OF MCN...WHERE THERE IS SOME SUPPORT FOR A VV001 1/4SM FG SITUATION...BUT NOT LIKELY. WX...ISOLD SHRA/TSRA S CENTRAL/SE PORTION SHOULD DISSIPATE AFTER SUNSET. ISOLD SHRA POSSIBLE AGAIN FAR S MONDAY...BUT THREAT APPEARS LESS THAN TODAY. OTHERWISE...NO WX EXPECTED THROUGH TAF VALID PERIOD. WINDS...GIVEN SYNOPTIC PATTERN...EXPECT EASTERLY FLOW TO REMAIN IN PLACE FOR THE NEXT SEVERAL DAYS. WINDS TODAY HAVE BEEN QUITE A BIT STRONGER THAN EXPECTED WITH 10-15KTS AND GUSTS TO 20KTS OR BETTER. MODELS SUPPORT WINDS JUST AS STRONG OR STRONGER MONDAY...THUS WILL BE INTRODUCING GUST AT MANY LOCATIONS. GENERALLY EXPECTING WIND DIRECTION AROUND 090 WITH SPEEDS 10-15KTS GUST TO 18KTS DAYTIME...5-8KTS AT NIGHT. && .PRELIMINARY POINT TEMPS/POPS... ATLANTA 65 82 63 80 / 5 5 10 10 ATHENS 64 82 63 80 / 5 5 10 10 GAINESVILLE 62 82 62 82 / 5 5 10 10 ROME 64 88 61 84 / 5 5 5 5 COLUMBUS 68 86 67 84 / 10 5 10 10 MACON 68 85 64 83 / 10 20 10 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 12/19/49 ga AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 545 PM EDT SUN OCT 2 2005 .SHORT TERM... UPPER LEVEL RIDGING ALOFT CONTINUES TO PROVIDE EASTERLY FLOW OVER FORECAST AREA THROUGH SHORT TERM PERIODS. SURFACE HIGH PRESSURE OFF THE NEW ENGLAND COAST WILL STRENGTH AS IT SHIFTS EASTWARD THROUGH WEDNESDAY...INCREASING ATLANTIC MOISTURE AS WEAK WAVES MOVE ACROSS FORECAST AREA TONIGHT AND THEN AGAIN TOMORROW EVENING. GOOD MOISTURE WILL CONTINUE TO PROVIDE PARTLY TO MOSTLY CLOUDY SKIES THROUGH THE SHORT TERM WITH LITTLE INSTABILITY NOTED. TEMPERATURES WILL CONTINUE TO TREND TOWARD COOLER NORMAL VALUES ALTHOUGH EXPECT THEM TO REMAIN A DEGREE OR TWO WARMER THAN NORMAL. .LONG TERM... WEAKENING UPPER LEVEL RIDGING WILL KEEP SHORT WAVE MOVING OUT OF PACIFIC NORTHWEST ON TUESDAY NORTH OF FORECAST AREA AS IT MOVES ACROSS THE UPPER PLAINS ON WEDNESDAY AND GREAT LAKES AREA ON THURSDAY. GFS INDICATING SURFACE FRONT ASSOCIATED WITH SHORT WAVE WILL PUSH THROUGH FORECAST AREA LATE WEDNESDAY NIGHT EARLY THURSDAY... HOWEVER WITH MUCH OF THE UPPER LEVEL SUPPORT NORTH OF AREA ONLY SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED. GFS CONTINUES TO SHOW DRIER AIR IS SLOW TO PUSH INTO FORECAST AREA AND WILL CONTINUE TO RAISE TEMPERATURES DAY 6 AND 7 AS COLDEST AIR REMAINS NORTH OF FORECAST AREA. && .AVIATION... OVERALL PATTERN OF THE PAST COUPLE OF DAYS REMAINS IN PLACE. UPPER AND SURFACE HIGH TO THE NORTHEAST OF THE REGION WITH TROPICAL LOW EASTERN GULF/CUBA AREA. NO SIGNIFICANT CHANGE TO PATTERN FORECAST THROUGH MONDAY. AS THE TROPICAL LOW BEGINS TO DRIFT WEST ON THE SOUTH SIDE OF THE SUBTROPICAL HIGH DURING THE WEEK...A FEEDER BAND OF DEEP TROPICAL MOISTURE WILL BE PULLED NORTHWARD ACROSS THE AREA. AT THIS POINT...THIS SHOULD NOT HAVE A SIGNIFICANT IMPACT ON THE AREA UNTIL AT LEAST WEDNESDAY. UNTIL THEN...LITTLE DAY-TO-DAY CHANGE. CEILINGS...VERY GOOD CU/TCU FIELD OBSERVED THIS AFTERNOON WITH DEEP EASTERLY/TROPICAL AIR MASS IN PLACE. SUFFICIENT INSTABILITY AND MOISTURE TO ALLOW FOR A FEW SHOWERS IN THE ATL AREA...WITH ISOLATED THUNDERSTORMS SE OF MCN. SOME MID/HIGH CLOUD DEBRIS WILL BE LEFT OVER THE AREA FROM CONVECTION TO THE SOUTH THROUGH THE EVENING. CONDITIONS DO NOT APPEAR TO BE AS FAVORABLE FOR LOW CLOUD DEVELOPMENT MONDAY MORNING AS THEY HAVE BEEN. GFS AND RUC NOT REALLY ADVERTISING DEVELOPMENT OF EARLY MORNING LOW CLOUDS...HOWEVER ETA IS. MOST AREAS SHOULD HAVE VFR CIGS THROUGH EARLY MORNING...THEN MVFR AT WORST FOR THE EARLY MORNING HOURS. THIS WILL PROBABLY BEST BE HANDLED VIA A TEMPO GROUP GIVEN CURRENT UNCERTAINTY. VISIBILITY...WITH LESS LOW CLOUDINESS EXPECTED OVERNIGHT...REDUCTIONS TO VISIBILITY MAY BE MORE WIDESPREAD TONIGHT. MOST AREAS SHOULD REMAIN MVFR AT WORST...WITH THE POSSIBLE EXCEPTION OF MCN...WHERE THERE IS SOME SUPPORT FOR A VV001 1/4SM FG SITUATION...BUT NOT LIKELY. WX...ISOLD SHRA/TSRA S CENTRAL/SE PORTION SHOULD DISSIPATE AFTER SUNSET. ISOLD SHRA POSSIBLE AGAIN FAR S MONDAY...BUT THREAT APPEARS LESS THAN TODAY. OTHERWISE...NO WX EXPECTED THROUGH TAF VALID PERIOD. WINDS...GIVEN SYNOPTIC PATTERN...EXPECT EASTERLY FLOW TO REMAIN IN PLACE FOR THE NEXT SEVERAL DAYS. WINDS TODAY HAVE BEEN QUITE A BIT STRONGER THAN EXPECTED WITH 10-15KTS AND GUSTS TO 20KTS OR BETTER. MODELS SUPPORT WINDS JUST AS STRONG OR STRONGER MONDAY...THUS WILL BE INTRODUCING GUST AT MANY LOCATIONS. GENERALLY EXPECTING WIND DIRECTION AROUND 090 WITH SPEEDS 10-15KTS GUST TO 18KTS DAYTIME...5-8KTS AT NIGHT. && .PRELIMINARY POINT TEMPS/POPS... ATLANTA 65 82 63 80 / 5 5 10 10 ATHENS 64 82 63 80 / 5 5 10 10 GAINESVILLE 62 82 62 82 / 5 5 10 10 ROME 64 88 61 84 / 5 5 5 5 COLUMBUS 68 86 67 84 / 10 5 10 10 MACON 68 85 64 83 / 10 20 10 10 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 12/19 ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GAYLORD MI 1015 PM EDT SUN OCT 2 2005 .UPDATE...UPPER TROUGH AXIS SLIDING INTO NE WISCONSIN ATTM PER PROFILERS TO THE WEST...MAIN ACTION HAD BEEN WITH VORT MAX AT BASE OF THIS TROUGH MOVING THROUGH SRN LAKE MICHIGAN. HOWEVER...ACTION HAS PICKED UP ALONG UPPER TROUGH AXIS OVER THE LAST HOUR. ELEVATED WARM/MOISTURE FRONT AROUND 925MB SEEN MOVING NORTHEAST FROM NE WISCONSIN TO CENTRAL LAKE MICHIGAN TO SRN LWR MICHIGAN. BEHIND THE FRONT...SCATTERED SHOWERS AND STORMS HAS LIVED/DEVELOPED IN JUICY AIR MASS...AS THETA-E RUNNING IN THE 328-336K. ELEVATED INSTABILITY DECENT TOO...WITH 100MB MLCAPE OF 500-1500J/KG AND LI'S OF -1C TO -2C. SOME LOW LEVEL MOISTURE HAS ALREADY STREAMED UP LAKE MICHIGAN WITH SFC OBS INDICATING HAZE ALONG THE EASTERN SHORE OF LAKE MICHIGAN FROM PLN TO MBL...AND ACROSS LAND AREAS JUST SOUTH OF THE CWA (SFC TD BOUNDARY RESIDES). AREA TAMDAR AND 00Z APX SOUNDINGS REFLECTING AIR MASS IS INITIALLY WAY TOO DRY TO SUPPORT CONVECTION...BUT WITH WARM FRONT SURGING INTO NRN MICHIGAN TONIGHT...925MB TD'S INCREASE TO +17C TO +18C VIA 30-35KT SOUTHERLY WINDS. MOISTENING THE LOW LAYERS OF THE ATMOSPHERE IS A QUICK WAY TO DECREASE THE OVERALL ATMOSPHERIC STABILITY...WHICH FOR TONIGHT...RESULTS IN UP TO 1500 J/KG PER MODIFICATION OF THE LATEST RUC SOUNDINGS...WITH ONLY 10-20J/KG OF CAP. HARD TO LOCATE A FOCUSING MECHANISM OUTSIDE OF THE UPPER TROUGH AXIS...WHICH WILL AFFECT THE NW PORTION OF THE CWA...WHERE CURRENT FORECAST OF LIKELY PRECIP RESIDES. PLUS...SHOULD HAVE HELP WITH AXIS/NOSE OF 40KT LLJ AND GREATEST H8-H5 -DIVQ. WILL LEAVE POP FORECAST THE WAY IT IS. FURTHER SOUTH...LATEST DATA COMING IN SUGGESTS THAT INSTABILITY WILL NOT BE AS HIGH...AND IT IS HARD TO LOCATE A LOW LEVEL BOUNDARY AS A FOCUS FOR THE CONVECTION. SCATTERED MAY EVEN BE OVERDONE...BUT CANNOT ARGUE IT WITH SUCH LITTLE CINH. UPPER TROUGH SHOULD ALLOW PRECIP TO BEGIN FROM NRN LAKE MICHIGAN/TRAVERSE CITY REGION AROUND MIDNIGHT...WHICH WILL PROPAGATE NE THROUGH THE CWA. AS FAR AS SEVERE GOES...OVERALL WIND FIELDS ARE NOT IMPRESSIVE. BULK SHEAR VALUES 25KTS OR LESS DOES NOT SUPPORT GOOD STORM ORGANIZATION...SEVERE THREAT IS MINIMAL AT BEST. ONGOING FORECAST SEEMINGLY IN LINE AND WILL ONLY BE MAKING ADJUSTMENTS TO THE TEMP GRIDS. WILL BE A WARM NIGHT WITH READINGS IN THE UPPER 50S TO LOWER 60S. MARINE...STABLE CONDITIONS OVER THE LAKES TONIGHT WITH LAKE SFC T'S RUNNING +16C TO 20C AND 950MB TEMPS RISING TO 21C. THIS SHOULD PROHIBIT ALL OF THE 35KTS AT 950MB FROM REACHING THE SFC. CAN SEE AS MUCH AS 15-25KTS OVER LAKE MICHIGAN/WHITEFISH POINT WITH LARGE FETCH BRINGING 3-6 FOOT WAVES INTO LAKE MICHIGAN. WILL KEEP SMALL CRAFT ADVISORIES WHERE THEY ARE...AND WATCH OTHER MARINE/LAND OBS FOR POSSIBLE ADVISORIES ELSEWHERE. SMD && .PREV DISCUSSION ISSUED AT 345 PM EDT SUN OCT 2 2005 DISCUSSION...PER WATER VAPOR IMAGERY THIS AFTERNOON...UPPER LOW WAS LIFTING NE THROUGH THE MID MS RIVER VALLEY. AHEAD OF THIS FEATURE...SURFACE DEWPOINT BOUNDARY...REPRESENTING A TRANSITION FROM DEWPOINTS MID 50S/LOWER 60S TO DEWPOINTS 65-70F...WAS PUSHING INTO THE S/SW LAKES. PER LIGHTNING DATA...CONVECTION WAS CONCENTRATED WITHIN THE UPPER LOW COLD POOL...AND SHOWERS/THUNDERSTORMS WERE SPREADING N/NE ALONG/SOUTH OF SURFACE BOUNDARY. PRIMARY FORECAST CONCERNS THROUGH TUESDAY INCLUDE POPS... THUNDERSTORM POTENTIAL AND MARINE WINDS. WITH MINOR DISAGREEMENT REGARDING DETAILS...12Z GUIDANCE STRONGLY SUGGESTS THAT THE UPPER LOW WILL LIFT NE THROUGH THE FORECAST AREA WITH SHOWERS TONIGHT...WITH ELEVATED CAPES (FROM 950-900 MB 500-1000 J/KG PER GFS/1000-1500 J/KG PER NAM) AND UPSTREAM TRENDS JUSTIFYING A MENTION OF THUNDERSTORMS. GIVEN DRY AIRMASS STILL IN PLACE ACROSS THE REGION AND TIMING UPSTREAM FEATURES...WILL EXTEND DRY FORECAST UNTIL 2Z. THEN...WHERE STRONGEST LOW LEVEL CONVERGENCE/DEEP LAYER ASCENT/STRONGEST ELEVATED INSTABILITY COINCIDE...ACROSS N/W COUNTIES...12Z GUIDANCE AND UPSTREAM TRENDS FAVOR RAISING POPS TO AT LEAST LIKELY IN THIS PACKAGE...AND CATEGORICAL POPS MAY EVEN BE NEEDED IN LATER PACKAGES. ACROSS E/SE COUNTIES...ON SOUTHERN PERIPHERY OF BEST FORCING/BEST ELEVATED INSTABILITY...CONFIDENCE REGARDING PRECIP COVERAGE IS REDUCED...WITH THE 12Z NAM/UKMET PUSHING MOST PRECIP NORTH...WHILE THE GFS TURNS THE SHORTWAVE TO THE EAST...WITH ASSOCIATED ASCENT/CONVECTION SPREADING EAST ALONG THE NOSE OF A 40-45 KNOT 850 MB JET...BACKING THE LOW LEVEL FLOW MORE AGGRESSIVELY THAN INDICATED BY THE 12Z NAM. WHILE THIS SCENARIO IS PLAUSIBLE...NOT SURE IF THE CORE OF THE SHORTWAVE WILL TURN SO FAR TO THE EAST GIVEN THE RIDGE POSITION OVER THE EASTERN US. THUS...WILL CONTINUE 40-50% POPS ACROSS E/SE COUNTIES OVERNIGHT...AND WILL LEAVE POPS ADJUSTMENTS THERE...IF ANY...TO LATER SHIFTS. AFTER THE OVERNIGHT PRECIP SCENARIO SPILLS INTO THE 12Z-14Z TIME FRAME...WILL TAPER POPS TO CHANCE ALL AREAS THROUGH MIDDAY MONDAY. THEN...TRICKY FORECAST MONDAY AFTERNOON...AS GFS DEPICTS STRONGER SUBSIDENCE/DRYING IN WAKE OF DEPARTING SHORTWAVE...WHILE THE NAM SUGGESTS THAT ADDITIONAL SHOWERS/THUNDERSTORMS WILL FIRE ACROSS NORTHERN COUNTIES DUE TO PROXIMITY OF SURFACE BOUNDARY/ASSOCIATED VORT AXIS TO THE N/NW OF REGION AND POOLING OF LOW LEVEL MOISTURE/INSTABILITY SOUTH OF THE BOUNDARY. HOWEVER...BECAUSE THE NAM MAY BE PUSHING THESE FEATURES A BIT TOO FAR TO THE S/SE (GFS/UKMET PLACE FEATURES FARTHER NORTH)...BECAUSE STRONGER DEEP LAYER SHEAR/MID LEVEL WINDS WILL REMAIN WELL N/NW OF THE FORECAST AREA AND BECAUSE OF THE ONGOING DRY FORECAST...WILL NOT YET ADD ANY POPS TO THE FORECAST AFTER 18Z MONDAY. HOWEVER...THIS IS NOT A HIGH CONFIDENCE FORECAST...AND WOULD NOT BE SURPRISED IF POPS ARE NEEDED IN LATER FORECASTS. ACROSS NEARSHORE AREAS...MARINE LAYER SHOULD REMAIN STABLE THOUGH MONDAY...SO 35-45 KNOT 950 MB WINDS SHOULD REMAIN ALOFT. HOWEVER...THE SURFACE PRESSURE GRADIENT...LOCAL ENHANCEMENT AND HIGHER WAVES AT THE END OF THE FETCH ACROSS N LAKE MICHIGAN ALL SUPPORT SMALL CRAFT ADVISORIES FOR WHITEFISH BAY AND LAKE MICHIGAN NEARSHORE AREAS TONIGHT THROUGH MONDAY. ROWLEY MONDAY NIGHT THROUGH TUESDAY...AFTER SHORTWAVE PASSAGE TOMORROW... SUBTLE UPPER RIDGING RE-ESTABLISHES ACROSS THE STATE MONDAY NIGHT WITH DRY WEATHER STILL EXPECTED. THEN...NEXT FORECAST PROBLEM DEALS WITH FRONT GRADUALLY LAYING ACROSS THE WESTERN GREAT LAKES AND PRECIP CHANCES ALONG/BEHIND THE FRONT. NAM/GFS80 DEVELOP BAND OF STRONG H8-H5 LAYER F-FGEN BEHIND THE FRONT ACROSS SOUTHERN ONTARIO... AND RESULTANT UPWARD VERTICAL MOTION FIELD ACROSS THE NRN GREAT LAKES. HOWEVER...SOLUTIONS DIFFER OVER POSITION OF THE UPPER RIDGE AND SFC FRONT WITH THE ETA SAGGING THE FRONT AND WIDESPREAD PRECIP DOWN INTO NRN LOWER MICHIGAN ON TUESDAY. BUT...PREFER THE SLIGHTLY MORE AMPLIFIED LOOK OF THE GFS (ALSO SUPPORTED BY THE ECMWF AND UKMET) WHICH KEEPS HEIGHTS HIGHER ACROSS NRN MICHIGAN THROUGH TUESDAY AND THE FRONT/RAINFALL JUST NORTH OF THE AREA THROUGH TUESDAY (FROPA EXPECTED WED...SEE BELOW). IT'S CLOSE...AND ONE CAN MAKE AN ARGUMENT FOR INTRODUCING AT LEAST A CHANCE FOR SHOWERS IN EASTERN UPPER MI BOTH TUESDAY AND TUESDAY NIGHT. BUT PREVIOUS DRY FORECAST IS BASED ON THIS SAME MORE AMPLIFIED PREMISE AND WILL THUS MAINTAIN CONTINUITY (AND COLLABORATION WITH MQT) AND KEEP THE FORECAST DRY. WEDNESDAY THROUGH SUNDAY (EXTENDED)...OPERATIONAL GFS/ECMWF IN DECENT AGREEMENT THROUGH THE EXTENDED PERIODS MAINTAINING A SOMEWHAT PROGRESSIVE HEMISPHERIC PATTERN AND LONGWAVE TROF POSITION ACROSS THE EASTERN PACIFIC. WEATHER ACROSS THE GREAT LAKES WILL REMAIN DOMINATED BY GENERALLY ABOVE NORMAL HEIGHTS/TEMPS EARLY IN THE WEEK...BUT A FAIRLY VIGOROUS WAVE MIGRATING OUT OF THE EPAC LONGWAVE TROF AND ACROSS THE NRN CONUS FOR MID WEEK WILL BRING ANOTHER BRIEF COOL DOWN AND TASTE OF FALL TO THE STATE. WEDNESDAY THROUGH FRIDAY...PRIMARY FORECAST ISSUE REVOLVES AROUND TIMING OF THE SHORTWAVE/SFC LOW/COLD FRONT THROUGH THE STATE FOR MIDWEEK. AFTER A COUPLE DAYS TRENDING FASTER...GFS/ECMWF NOW SLOWING THINGS DOWN JUST A LITTLE BRINGING THE FRONT THROUGH THE STATE LATER WEDNESDAY AND UPPER WAVE/CORE OF COLDEST AIR THROUGH THE GREAT LAKES THU/FRI. BULK OF THE PRECIP APPEARS PRIMARILY POST-FRONTAL AND SUGGESTS GREATEST PRECIP CHANCES WILL HOLD OFF UNTIL WEDNESDAY NIGHT. BUT...IT'S NOT THE FORECAST THAT GOES WRONG IT'S THE TIMING...AND TOUGH TO HANG YOUR HAT ON TIMING 3 DAYS OUT WHICH IS WHY WE USUALLY DO NOT GO POPS > CHANCE IN LATER PERIODS. BUT GIVEN THE VERY GOOD AGREEMENT AMONG THE ECMWF/GFS/ETA WITH REGARD TO FROPA WILL TREND HIGHEST POPS FORWARD INTO THE WED AFTERNOON/NIGHT TIMEFRAME. CORE OF COLDEST AIR SLIPS INTO THE GREAT LAKES THURSDAY AND BRINGS THE POTENTIAL FOR LAKE EFFECT AND DIURNAL SHOWERS DURING THE DAY. GFS/ECMWF BOTH FORECASTING A FAIRLY COLD SHOT OF AIR WITH THE UPPER TROF DIPPING 850 MB TEMPS TO THE -4C TO -8C RANGE OVER THE NRN GREAT LAKES THURSDAY NIGHT RAISING THE POSSIBILITY OF SNOW AWAY FROM THE LAKES (NEED TO GET 850 MB TEMPS DOWN TO -5C OR COLDER THIS TIME OF YEAR TO EVEN THINK ABOUT SNOW). BUT AT THE SAME TIME VERY STRONG HIGH PRESSURE FORECAST TO BUILD INTO ONTARIO VEERING WINDS INTO AN UNFAVORABLE NORTH FLOW REGIME. KEEP IN MIND THAT MEDIUM RANGE MODELS TEND TO OVER DO MAGNITUDE OF COLD AIR IN LATER PERIODS...BUT IF THE CURRENT SOLUTIONS ARE CLOSE UPPER MICHIGAN (MAINLY THE HIGH TERRAIN OF CENTRAL AND WESTERN UPPER) MAY SEE SOME SNOW THURSDAY NIGHT. GIVEN THE UNFAVORABLE FLOW REGIME WILL LIMIT PRECIP CHANCES THURSDAY NIGHT TO JUST THE WESTERN PORTION OF CHIP/MACK COUNTIES. FRIDAY THROUGH SUNDAY...STRONG HIGH PRESSURE SLOWLY DRIFTS THROUGH THE REGION AND DOMINATES DURING THIS TIME WITH CORE OF COLD AIR SLIDING OUT OF THE AREA AND TEMPS ONCE AGAIN REBOUNDING. ADAM && .APX...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 945 PM EDT SUN OCT 2 2005 .DISCUSSION... .SHORT TERM... 00Z RAOBS/WV IMAGERY AND RUC ANALYSIS SHOW PERSISTENT HI AMPLITUDE UPR RDG STRETCHING FM TX TO NEW ENGLAND. DEEP TROF NOTED OFF THE W COAST...AND UPR GRT LKS IN WARM SW FLOW ALF BTWN THESE FEATURES. SHRTWV EMBEDDED WITHIN THIS SW FLOW ALF PRESENT OVER WI THIS EVNG... AND THIS SYS CAUSING SOME SHRA/TSRA FM ARND MNM SE INTO SW LWR MI WHERE 12HR MOISTENING HAS BEEN SUBSTANTIAL (12Z PWAT AT GRB WAS 1.03 INCHES...00Z PWAT UP TO 1.55 INCHES). BUT MUCH OF FA STILL UNDER THE DOMINATION OF DRIER/MORE STABLE AIRMASS DEPICTED ON THE 00Z APX SDNG/TAMDAR SDNG FM SAW. BUT BOTH THESE SDNGS SHOW HI LLVL RH BLO SUBSIDENCE INVRN BTWN H85-9...AND SFC DWPTS HAVE INCRSD INTO THE 60 TO 65 RANGE ACRS MUCH OF THE FA WITH 30-45KT SLY WINDS NOTED ON THE MQT VWP FM 2K FT-5K FT MSL. SO EVEN THOUGH DEEP CLD IS ABSENT... COMBINATION OF DIURNAL COOLING AND UPSLOPE SSE FLOW AHEAD OF SHRTWV HAVE CAUSED SOME LO CLD TO DVLP OVER THE CNTRL AND E DOWNWIND OF LK MI AS SHOWN ON VISFOG STLT IMAGERY. BKN SC NOTED OVER MUCH OF WI... CIGS HGTS ARE GENERALLY IN THE VFR 3K-5K FT RANGE THERE. MAIN FCST CONCERNS TNGT REVOLVE ARND PCPN/CLD/FOG TRENDS AND IMPACT OF INCRSG CLD/MSTR ON LO TEMPS. 18Z GFS F6 APPEARS TO HAVE BEST HANDLE ON ONGOING WX...ESPECIALLY HI STABILITY OVER THE FA ATTM...SO RELYING ON THIS MODEL MOST HEAVILY FOR UPDATE. GFS SHOWS WI SHRTWV DRIFTING NEWD TNGT AND INTO ONTARIO BY 12Z MON. GFS SHOWS MOST IMPRESSIVE H85 MSTR CNVGC IN AREA WHERE SHRA NOW PRESENT...AND THIS AREA OF BEST MSTR CNVGC FCST TO DRIFT MORE ENEWD AS SFC-H85 WINDS PROGGED TO VEER SHARPLY OVERNGT WITH PASSAGE OF SHRTWV. SO GOING FCST OF HIER POPS TO THE E APPEARS ON TRACK. WL CONT MENTION OF SCT SHRA/A FEW TSRA E OF MQT-IMT. ALTHOUGH TEMPTATION IS THERE TO REMOVE POPS TO THE W ALTOGETHER...INFLUX OF MSTR FM THE SW AND ONLY SML CAP ABV INVRN AT H8 IN PRESENCE OF STEEP H8-5 LAPSE RATES SHOWN ON THE 00Z INL SDNG WARRANTS MENTION OF CONTD SLGT CHC POPS EVEN TO THE W. OTRW...INCRSG MSTR UNDER INVRN WL ALLOW FOR INCSG ST/SC COVG OVERNGT. THIS CLD AND FAIRLY STRG WIND VEERING FM S TO WSW WIND SHOULD RESTRICT FOG COVG/VSBY RESTRICTION. BUT WL FCST FOG TO EXPAND A BIT TNGT AS GFS SHOWS WIND SPEEDS DCRSG A BIT LATE. INCRSG MSTR/CLD AND STEADY WIND WL GREATLY RESTRICT DIURNAL TEMP FALL. KC .LONG TERM... MONDAY...GFS CONSISTENT SHOWING FRONTAL ZONE STALLING OUT JUST WEST OF FCST AREA. WITH 8H THETA-E RDG NEARBY AND SUGGESTION OF ANOTHER SHORTWAVE FROM THE CENTRAL PLAINS TO MOVE ALONG FRONTAL BOUNDARY BY AFT....KEPT IN SLGT CHC OF SHRA/TSRA FOR WRN COUNTIES. FCST SNDGS SHOW CAPPING OVER CENTRAL AND ERN COUNTIES SHOULD KEEP THESE ZONES DRY. 8H TEMPS OF AROUND 16C SHOULD AGAIN YIELD INLAND HIGHS IN THE UPR 70S AND LOW 80S. MONDAY NIGHT INTO TUE...12Z GFS SHOWED GOOD CONTINUITY WITH 06Z RUN STILL SHOWING FRONTAL BOUNDARY STALLED OVER WESTERN LAKE SUPERIOR. ANOTHER WEAK SHORTWAVE NOTED AND INCREASING ISENTROPIC LIFT AND 925-850 MB FRONTOGENESIS IS PROGGED OVER THE AREA SO WILL KEEP GOING CHC POPS IN FOR LATE MON NIGHT INTO TUE FOR WRN 1/3 OF CWA. GFS/ECMWF AND CANADIAN MODELS HAVE COME INTO BETTER AGREEMENT WITH TIMING OF STRONG SHORTWAVE TO MOVE ACROSS THE NORTHERN PLAINS AND MOVEMENT OF FRONTAL ZONE ACROSS FCST AREA ON WED. THE ASSOCIATED SURFACE LOW WILL DEVELOP OVER THE SOUTHERN PLAINS AND MOVE QUICKLY NORTHEAST ALONG THE FRONTAL BOUNDARY AS IT CROSSES THE UPPER GREAT LAKES WEDNESDAY INTO WEDNESDAY NIGHT. THERE IS NOW GOOD AGREEMENT ON THE TRACK OF THE SURFACE LOW AND WITH THE TREND TOWARD A SLOWER PROGRESSION OF SYSTEM...BELIEVE GFS TIMING LOOKS GOOD NOW. STRONG FRONTOGENESIS WILL COINCIDE WITH PASSAGE OF THE SHORTWAVE ON WEDNESDAY SO SPREAD LIKELY POPS ACROSS FCST AREA WED AFTERNOON. GFS CONSISTENT SHOWING HEAVIEST PCPN ASSOCIATED WITH THE DEFORMATION ZONE AND MID LEVEL FRONTOGENESIS GENERALLY BEHIND COLD FRONT. SO HELD OFF ON LIKELY POPS FOR ERN COUNTIES UNTIL WED NIGHT. WITH SLOWER TIMING OF FRONT BUMPED UP WED HIGHS MORE INTO 60S AND EVEN LOW 70S EAST WITH FCST AREA INITIALLY IN WARM SECTOR OF SFC LOW AND FRONTAL SYSTEM. VERY GUSTY NORTHWEST WINDS STILL GOOD LOOK LIKE A GOOD BET WEDNESDAY NIGHT INTO THU WITH A STRONG PRESSURE GRADIENT AND NICE PRESSURE RISE-FALL COUPLET FCST BY MODELS. STRONG CAA BEHIND FRONT WITH 8H TEMPERATURES DROPPING TO AROUND -6C TO -7C BY THU MORNING SHOULD RESULT IN SOME LAKE EFFECT SHOWERS...WHICH WILL PROBABLY MIX WITH SNOW...PARTICULARLY OVER THE HIGHER TERRAIN. WITH GOOD CYCLONIC FLOW NOW NOTED BY MOST OF MODELS THU BUMPED UP POPS TO LIKELY NORTH FOR LAKE EFFECT PCPN AND TO 40 PCT FOR SRN COUNTIES. WITH CYCLONIC FLOW NOTED BY MODELS...EXTENDED MENTION OF SCT SHRA/SHSN INTO THU NIGHT. MODEL CONSENSUS OF SFC HIGH AND DRIER AIR/SUBSIDENCE BLDG IN FOR FRI SO ENDED SHOWERS BY THAT TIME. WITH SLOWER PROGRESSION OF PATTERN...SLOWER EXIT OF SYSTEM TO EAST AND SLOWER ARRIVAL OF RDGG FROM WEST...HAD TO ALSO DELAY WARMING TREND FOR WEEKEND AS GFS NOW SUGGESTS 8H TEMPS NOT TO REBOUND ABOVE 0C UNTIL SAT. SO LOWERED HIGHS ON FRI TO 50S AND UPR 50S TO LOW 60S SAT. HIGHS SUN SHOULD REACH LOW TO MID 60S AS 8H TEMPS RISE TO AROUND 6-7C PER GFS/ECMWF FCST. VOSS && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 940 PM EDT SUN OCT 2 2005 .UPDATE... THE MAIN CONCERN FOR THE OVERNIGHT HOURS WILL BE COVERAGE OF SHOWERS AND THUNDERSTORMS. STILL ANTICIPATING A TRANSITION FROM SURFACE BASED CONVECTION TO ELEVATED AS THE NIGHT WEARS ON. THE LATEST RUC ANALYSIS FIELDS DEPICT FAIRLY WELL THE COMBINATION OF LOW LEVEL MOISTURE ADVECTION AND SHORT WAVE SUPPORT THAT IS ONGOING AND RESPONSIBLE FOR THE CURRENT PATTERN OF SHOWERS AND STORMS. THE COMBINATION OF THETA-E ADVECTION BELOW 700 MB AND DCVA FROM THE WAVE FAVORS LOCATIONS MAINLY NORTH AND WEST OF DETROIT FOR NEW SHOWER AND STORM DEVELOPMENT OVERNIGHT AND MONDAY MORNING. OUR GOING FORECAST IS IN GOOD SHAPE. THE THEME OF THE UPDATE WILL BE TO ADD SOME CONFIDENCE WITH AREAL COVERAGE TERMS RATHER THAN CHANCE TERMS IN THE PRECIP FORECAST AROUND FLINT AND THE TRI CITIES, NOW THAT WE HAVE ACTIVITY ON RADAR. WE'LL ALSO USE THIS UPDATE TO FRESHEN UP SOME OF THE OTHER ELEMENTS. THE TEMP FORECAST LOOKS GOOD BUT WITH READINGS EXPECTED TO COME IN NEAR THE WARM END OF THE RANGE. && .PREV DISCUSSION... (ISSUED 708 PM EDT SUN OCT 2 2005) AVIATION... CONCERNS REGARDING FOG AND THE CHANCE OF THUNDERSTORMS WILL IMPACT AVIATION INTERESTS TONIGHT THROUGH ABOUT NOON ON MONDAY. ONGOING STORMS AROUND THE SOUTH END OF LAKE MICHIGAN ARE BEING FORCED BY GOOD SURFACE BASED INSTABILITY WITH SOME UPPER LEVEL SUPPORT FROM THE SHORT WAVE OVER WISCONSIN AND ILLINOIS. EXPECT THE GENERAL TREND TO BE DOWNWARD ON THIS ACTIVITY WITH THE LOSS OF DAYTIME HEATING, WITH A TRANSITION TO ELEVATED SHOWERS AND STORMS BY LATE EVENING AND DURING THE OVERNIGHT HOURS. THIS TRANSITION FAVORS LOCATIONS NORTH OF DETROIT AS HAVING THE BEST CHANCE OF THUNDERSTORMS WHERE THE COMBINATION OF MOISTURE ADVECTION, STEEPER MID LEVEL LAPSE RATES, AND MODEST SUPPORT FROM THE FILLING WAVE COME TOGETHER. INCREASING SURFACE DEWPOINT WILL BE THE DRIVING FACTOR BEHIND FOG TONIGHT. SOUTH WIND IS EXPECTED TO STAY IN THE 5 TO 10 KNOT RANGE AND MINIMIZE RADIATIONAL COOLING, ALONG WITH CLOUD COVER, BUT SURFACE DEWPOINT RISING INTO THE MID AND UPPER 60S WILL RESULT IN AT LEAST AREAS OF MVFR FOG AS THE LONGER NIGHT UNFOLDS. EXPECT THE FOG TO LIFT SLOWLY AND THE PRECIP POTENTIAL TO DIMINISH DURING THE MORNING, FOLLOWED BY DRY AND VFR CONDITIONS DURING MONDAY AFTERNOON. PREV DISCUSSION... (ISSUED 308 PM EDT SUN OCT 2 2005) SHORT TERM...TONIGHT AND MONDAY WARM AND HUMID AIR CONTINUES TO SURGE NORTH INTO SOUTHER LOWER MICHIGAN THIS AFTERNOON...AS SURFACE DEW POINTS HAVE RISEN IN THE LOW TO MID 60S. UNLIKE MUCH OF THE SUMMER...THE MODELS ARE NOT OVERESTIMATING THE LOW LEVEL MOISTURE. ADDITIONAL LOW LEVEL MOISTURE WILL SPREAD INTO THE REGION THROUGH TONIGHT...AS DE-AMPLIFYING SHORTWAVE TROUGH OVER THE MIDWEST/WESTERN GREAT LAKES REACHES THE ONTARIO/QUEBEC BORDER MONDAY MORNING. MAIN FORCING WITH THIS SYSTEM WILL BE NORTH OF SOUTHEAST MICHIGAN. NONE-THE-LESS...ENOUGH SOUTHWARD EXTENSION/INSTABILITY/TROUGHINESS TO CONTINUE WITH CHANCE POPS...BEST CHANCE ACROSS TRI-CITIES REGION TONIGHT. SOUTHEAST MICHIGAN WILL REMAIN IN A MOIST AND UNSTABLE AIRMASS TOMORROW...AS SURFACE DEW POINTS CONTINUE TO HOVER WELL INTO THE 60S. WITH SHORTWAVE RIDGING EXPECTED DURING THE AFTERNOON HOURS AND A LACK OF A TRIGGER...WILL KEEP THE FORECAST DRY DURING THE AFTERNOON HOURS. ALTHOUGH THERE IS SOME DECENT INSTABILITY INDICATED (CAPES OVER 1000 J/KG ALONG WITH LI'S OF -3 C OR BETTER)...THE CAPE IS SKINNY AND THERE IS SUFFICIENT LOW LEVEL CIN (25-50 J/KG). CU RULES POINTING TO SCT-BKN CLOUD COVER. WITH PARTIAL SUNSHINE AND 925 MB TEMPS RUNNING AROUND 23 C...MAX TEMPS SHOULD EASILY CLIMB INTO THE LOW TO MID 80S. KEEP IN MIND...RECORD HIGHS ARE IN THE UPPER 80S FOR EARLY OCTOBER. LONG TERM...MONDAY NIGHT THROUGH SUNDAY THE TRANSITION OF THE SEASONS IS DEFINITELY THE CHALLENGE IN THE FORECAST FOR THE UPCOMING WEEK. THE WEATHER FOR THE FIRST HALF OF THE WEEK (INCLUDING TUESDAY/WEDNESDAY OF THE LONG TERM FORECAST) WILL BE RATHER SUMMER-LIKE. TEMPERATURES LOOK TO CLIMB INTO THE LOWER TO MID 80S OVER MUCH OF THE AREA ON TUESDAY...AND PERHAPS AGAIN ON WEDNESDAY DEPENDING ON THE TIMING OF A STRONG COLD FRONT. THE TREND TO A SLOWER PROGRESSION OF STRONG UPPER LEVEL STORM AND SAID FRONT CONTINUES IN THE 12Z RUNS...WHICH BODES WELL FOR ANOTHER WARM DAY. WILL KEEP TEMPERATURES AT OR JUST SHORT OF 80 (A SOLID 15 DEGREE ABOVE NORMAL FOR EARLY OCTOBER)...DUE TO THE POTENTIAL FOR INCREASED CLOUD COVER AND SHOWER/THUNDERSTORM ACTIVITY DURING THE LAST HALF OF THE DAY. ANY ADDITIONAL DELAY IN THIS SYSTEM MAY WARRANT AN EVEN WARMER FORECAST ON WEDNESDAY. THEREAFTER...COLD FRONT BLOWS THROUGH LOWER MICHIGAN WEDNESDAY NIGHT. MUCH COOLER CONDITIONS THEN SET UP ON THURSDAY/FRIDAY WITH A SLOW MODERATION INTO NEXT WEEKEND. DID NOT CHANGE MUCH IN THE FORECAST DURING THIS TIME-FRAME AS TEMPERATURES STRUGGLE TO REACH 60...AND LIKELY WILL NOT IN MANY AREAS. THIS BOUT OF COOL WEATHER WILL BE OF A LONGER DURATION THAN LAST WEEKS SYSTEM AS SPRAWLING HIGH PRESSURE SLOWLY SETTLES INTO THE GREAT LAKES FROM THURSDAY INTO THE WEEKEND. THIS WILL NOT ONLY KEEP HIGH TEMPERATURES AOB 60 THURSDAY AND FRIDAY...BUT PROVIDE FOR WIDESPREAD 30S FRIDAY MORNING...IF NOT INTO THE WEEKEND AS THE HIGH ACTUALLY SETTLES OVERHEAD AND PROVIDE THE BEST RADIATIONAL COOLING SCENARIO. BY THIS TIME...THE EDGE WILL BE TAKEN OFF AS THE AIRMASS WILL BE SIGNIFICANTLY MODIFIED. EVEN WITH SUCH COOL TEMPERATURES...WILL LEAVE FROST MENTION OUT OF THE FORECAST FOR THIS PACKAGE. WOULD LIKE TO NAIL DOWN THE TIMING OF ANY LEFTOVER LAKE EFFECT CLOUDS WHICH COULD DEFINITELY IMPEDE THE DEGREE OF COOLING THURSDAY NIGHT. EVEN INTO THE WEEKEND...WITH THE MODIFICATION OF THE AIRMASS...CONDITIONS BECOME MORE IFFY FOR FROST TO BE WIDESPREAD. GIVEN DEGREE OF TROUBLE THE MODELS HAVE HAD WITH THIS TRANSITION SO FAR...WOULD LIKE TO SEE A LITTLE MORE CONTINUITY BEFORE DELVING TOO DEEPLY INTO THE FROST POTENTIAL. CERTAINLY IS SOMETHING TO CONSIDER IN THE COMING DAYS THOUGH. WITH THIS HIGH PRESSURE AS THE DOMINANT WEATHER SYSTEM...DRY WEATHER WILL TAKE HOLD LATE THIS WEEK INTO THE WEEKEND...WITH LITTLE MORE THAN LAKE EFFECT SHOWERS...WHICH WILL HOLD ON THROUGH THURSDAY AND PERHAPS INTO THURSDAY NIGHT/EARLY FRIDAY IN ADVANCE OF THE CENTER OF HIGH PRESSURE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION/UPDATE...BT SHORT TERM...SF LONG TERM....DG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 500 PM EDT SUN OCT 2 2005 .DISCUSSION... MAIN FORECAST ISSUES ARE CHANCES FOR SHOWERS AND THUNDERSTORMS TONIGHT WITH SHORTWAVE MOVING UP THROUGH LOWER MIDWEST....CHANCES OF SHRA/TSRA MON INTO TUE WITH STALLED OUT FRONTAL BOUNDARY TO OUR WEST...THEN MORE SIGNIFICANT SYSTEM AND WIDESPREAD PCPN TO AFFECT OUR AREA FOR WED INTO THU. LATEST WATER VAPOR IMAGERY AND RUC UPPER AIR ANALYSES SHOW BROAD UPPER RIDGE OVER THE EASTERN HALF OF NORTH AMERICA WITH SIGNIFICANT TROUGHING DIGGING INTO THE PAC NW. A SHRTWV AND ASSOC CONVECTION CAN BE SEEN MOVING UP FROM LWR MIDWEST AS WELL. TONIGHT...UPSTREAM RADAR AND LIGHTNING DATA STILL SHOW SHOW QUITE A BIT OF CONVECTION OVER NRN IL WITH APPROACHING SHORTWAVE FROM LOWER MIDWEST. THIS CONVECTION IS SUPPORTED BY CONVERGENCE/LIFT AT NOSE OF A 45KT 850MB JET AS NOTED IN THE PROFILER DATA AND MORE UNSTABLE (6.5-7C/KM) 700-500 MB LAPSE RATES. MODELS CONTINUE TO SHOW THE SHORTWAVE SHEARING OUT AS IT MOVES NORTHEAST INTO MORE CONFLUENT FLOW THROUGH TONIGHT...ALTHOUGH INSTABILITY SHOULD STILL SUPPORT SOME CONVECTION...ESPECIALLY OVER THE ERN HALF OF FCST AREA. NOT EXPECTING AS GOOD OF A CHANCE OF CONVECTION OVER WEST ZONES AS 8H JET BECOMES MORE ORIENTED TO WSW THROUGH EVENING SO HAVE TRIMMED BACK TO SLIGHT CHC OVER WRN ZONES. AS SHORTWAVE LIFTS NORTH OF FCST AREA OVERNIGHT...EXPECT CONVECTION TO TAPER OFF. MONDAY...GFS CONSISTENT SHOWING FRONTAL ZONE STALLING OUT JUST WEST OF FCST AREA. WITH 8H THETA-E RDG NEARBY AND SUGGESTION OF ANOTHER SHORTWAVE FROM THE CENTRAL PLAINS TO MOVE ALONG FRONTAL BOUNDARY BY AFT....KEPT IN SLGT CHC OF SHRA/TSRA FOR WRN COUNTIES. FCST SNDGS SHOW CAPPING OVER CENTRAL AND ERN COUNTIES SHOULD KEEP THESE ZONES DRY. 8H TEMPS OF AROUND 16C SHOULD AGAIN YIELD INLAND HIGHS IN THE UPR 70S AND LOW 80S. MONDAY NIGHT INTO TUE...12Z GFS SHOWED GOOD CONTINUITY WITH 06Z RUN STILL SHOWING FRONTAL BOUNDARY STALLED OVER WESTERN LAKE SUPERIOR. ANOTHER WEAK SHORTWAVE NOTED AND INCREASING ISENTROPIC LIFT AND 925-850 MB FRONTOGENESIS IS PROGGED OVER THE AREA SO WILL KEEP GOING CHC POPS IN FOR LATE MON NIGHT INTO TUE FOR WRN 1/3 OF CWA. GFS/ECMWF AND CANADIAN MODELS HAVE COME INTO BETTER AGREEMENT WITH TIMING OF STRONG SHORTWAVE TO MOVE ACROSS THE NORTHERN PLAINS AND MOVEMENT OF FRONTAL ZONE ACROSS FCST AREA ON WED. THE ASSOCIATED SURFACE LOW WILL DEVELOP OVER THE SOUTHERN PLAINS AND MOVE QUICKLY NORTHEAST ALONG THE FRONTAL BOUNDARY AS IT CROSSES THE UPPER GREAT LAKES WEDNESDAY INTO WEDNESDAY NIGHT. THERE IS NOW GOOD AGREEMENT ON THE TRACK OF THE SURFACE LOW AND WITH THE TREND TOWARD A SLOWER PROGRESSION OF SYSTEM...BELIEVE GFS TIMING LOOKS GOOD NOW. STRONG FRONTOGENESIS WILL COINCIDE WITH PASSAGE OF THE SHORTWAVE ON WEDNESDAY SO SPREAD LIKELY POPS ACROSS FCST AREA WED AFTERNOON. GFS CONSISTENT SHOWING HEAVIEST PCPN ASSOCIATED WITH THE DEFORMATION ZONE AND MID LEVEL FRONTOGENESIS GENERALLY BEHIND COLD FRONT. SO HELD OFF ON LIKELY POPS FOR ERN COUNTIES UNTIL WED NIGHT. WITH SLOWER TIMING OF FRONT BUMPED UP WED HIGHS MORE INTO 60S AND EVEN LOW 70S EAST WITH FCST AREA INITIALLY IN WARM SECTOR OF SFC LOW AND FRONTAL SYSTEM. VERY GUSTY NORTHWEST WINDS STILL GOOD LOOK LIKE A GOOD BET WEDNESDAY NIGHT INTO THU WITH A STRONG PRESSURE GRADIENT AND NICE PRESSURE RISE-FALL COUPLET FCST BY MODELS. STRONG CAA BEHIND FRONT WITH 8H TEMPERATURES DROPPING TO AROUND -6C TO -7C BY THU MORNING SHOULD RESULT IN SOME LAKE EFFECT SHOWERS...WHICH WILL PROBABLY MIX WITH SNOW...PARTICULARLY OVER THE HIGHER TERRAIN. WITH GOOD CYCLONIC FLOW NOW NOTED BY MOST OF MODELS THU BUMPED UP POPS TO LIKELY NORTH FOR LAKE EFFECT PCPN AND TO 40 PCT FOR SRN COUNTIES. WITH CYCLONIC FLOW NOTED BY MODELS...EXTENDED MENTION OF SCT SHRA/SHSN INTO THU NIGHT. MODEL CONSENSUS OF SFC HIGH AND DRIER AIR/SUBSIDENCE BLDG IN FOR FRI SO ENDED SHOWERS BY THAT TIME. WITH SLOWER PROGRESSION OF PATTERN...SLOWER EXIT OF SYSTEM TO EAST AND SLOWER ARRIVAL OF RDGG FROM WEST...HAD TO ALSO DELAY WARMING TREND FOR WEEKEND AS GFS NOW SUGGESTS 8H TEMPS NOT TO REBOUND ABOVE 0C UNTIL SAT. SO LOWERED HIGHS ON FRI TO 50S AND UPR 50S TO LOW 60S SAT. HIGHS SUN SHOULD REACH LOW TO MID 60S AS 8H TEMPS RISE TO AROUND 6-7C PER GFS/ECMWF FCST. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ VOSS mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1210 AM EDT SUN OCT 2 2005 .DISCUSSION... THE MAIN CONCERN WITH THIS UPDATE IS THE TEMPERATURES THIS AFTERNOON AND THE ONSET OF THE POTENTIAL SHOWERS. WATER VAPOR IMAGERY AND RUC/ETA SHOWING A CLOSED LOW OVER MPX AREA MOVING THROUGH A RIDGE OVER EASTERN ONTARIO AND WESTERN QUEBEC. THIS RIDGE IS SHIFTING THE SHORTWAVE NORTHEAST INTO THE FORECAST AREA BY THIS EVENING. ELEVATED CONVECTION IS GENERATE THUNDERSTORMS OVER NORTHERN MISSOURI AND NORTHWEST ILLINOIS. SURFACE ANALYSIS INDICATE A DEEP LOW OVER SOUTHERN MANITOBA WITH A COLD FRONT DRAPED TO THE SOUTHWEST ACROSS THE DAKOTAS. THE FLOW AHEAD OF THE LOW WILL KEEP THE WINDS OUT OF THE SOUTH THROUGH THE AFTERNOON. LOW LEVEL MOISTURE IS RATHER LIMITED OVER THE UPPER GREAT LAKES. AS THE SHORTWAVE APPROACHES THIS AFTERNOON...CLOUD COVER SHOULD INCREASE OF THE WESTERN U.P. THE SURFACE LOW WILL EDGE INTO SOUTHEAST MANITOBA USHERING THE COLD FRONT INTO EASTERN DAKOTAS. MOIST AIR WILL ADVECT INTO CENTRAL WISCONSIN BY 21Z ALONG WITH THE SHORTWAVE. THIS ALSO FAVORS AN INCREASE OF CLOUD COVER OVER THE WESTERN U.P. THIS AFTERNOON. THE SOUTHERLY FLOW WILL KEEP WARM AIR ADVECTION ACROSS THE REGION FORECAST AREA THIS AFTERNOON PUSHING THE TEMPERATURES ABOVE THE PROJECTED. THE ELEVATED CONVECTION WILL START TO INCREASE OVER THE WEST THIS AFTERNOON...HOWEVER...THE DRY CONDITIONS WILL LIMIT THE CHANCE OF PRECIPITATION. THUS WILL TWEAK SOME OF THE WINDS AND TEMPERATURES IN THE FORECAST FOR THIS AFTERNOON ONLY. THE POPS SHOULD INCREASE THIS EVENING OVER THE WEST AND SPREAD EAST. AS THE SHORTWAVE...INCREASE MOISTURE OVER THE WEST...AND ELEVATED CONVECTION MOVES OUT OF WISCONSIN INTO THE FORECAST AREA. THE TONIGHT FORECAST STILL COVERS THIS CONDITIONS SATISFACTORILY...SO WILL NOT UPDATE THAT AT THIS TIME. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 738 AM EDT SUN OCT 2 2005 .AVIATION... GENERALLY LIGHT/THIN MIST/FOG AT KDTW/KDET/KFNT...MOSTLY MVFR VISIBILITY...EXPECTED TO BURN OFF BY 14Z. THEREAFTER...SOLIDLY VFR WITH FEW TO SCATTERED DIURNAL CUMULUS 4K TO 5K FEET TODAY AND HIGH TO OCCASIONAL MID CLOUDS THROUGH MOST OF TONIGHT. BY 08Z HAVE CALLED FOR MID CLOUD CEILINGS...VISIBILITIES 5 MILES IN MIST/FOG...AS LOW MOISTURE INCREASE AND EXPECTED LIMITED NIGHTTIME RADIATION COMBINE FOR SLIGHTLY REDUCED VISIBILITIES. BELIEVE THAT ANY DYNAMICS FROM EJECTING SHORTWAVE TROUGH SYSTEM FROM THE SOUTHWEST WILL BE WEAK AND MAINLY CONFINED TO SAGINAW VALLEY LATE TONIGHT...SO HAVE CALLED FOR PROB30 GROUP AT KMBS/KFNT FROM 08Z TO 12Z FOR 4 MILES IN SHOWERS. && .PREV DISCUSSION... (ISSUED 425 AM EDT SUN OCT 2 2005) SHORT TERM...TODAY AND TONIGHT SOUTHERLY SURFACE WINDS CONTINUING THROUGH TONIGHT AS COLD FRONT ADVANCES INTO FAR WESTERN GREAT LAKES REGION. AT 500 MB...CENTRAL PLAINS SYSTEM OPENING UP AND LIFTING INTO UPPER MISSISSIPPI VALLEY TODAY AND CONTINUING NORTHEAST TONIGHT WHILE WEAKENING...WITH VORTICITY LOBE MOVING INTO FORECAST AREA LATE TONIGHT. 850 TO 500 MB MOISTURE SHOWS DRYNESS HOLDING ON UNTIL TONIGHT...INCREASING MAINLY LATE TONIGHT. AT 925 MB...HIGHER RELATIVE HUMIDITIES INCHING UP FROM THE SOUTH TODAY AND CONTINUING TONIGHT. MOISTURE AT STILL HIGHER LEVELS THAN THIS REACHING THE AREA SOONER...AS SEEN VIA IR IMAGERY. LOW LEVEL THETA E RIDGE WORKING IN ESPECIALLY TONIGHT...WITH HIGHER LEVEL THETA E RIDGE MAINLY INTO FAR NORTHWEST. DYNAMICS VERY MODEST AT BEST TO GO ALONG WITH THE BETTER MOISTURE TONIGHT. LOW TO MID LEVEL OMEGA LIFT SLIGHT AND VERY MODEST 305K ISENTROPIC ASCENT TONIGHT...WITH CONDENSATION PRESSURE DEFICITS LOWERING ONLY TO ABOUT 30 MB WEST LATE...MAINLY AS PER NAM. RUC AND NAM AND GFS SHOW LIFTED INDICES SLIGHTLY UNSTABLE TONIGHT...WITH MODEST CAPES ESPECIALLY WEST...ALBEIT CONVECTIVE INHIBITION FAIRLY GOOD MOST OF TONIGHT. 850 TO 700 MB LAPSE RATES FAIRLY STEEP OVERNIGHT...PROBABLY NAM OVERDONE HERE WITH TOO HIGH OF DEW POINTS. TOTAL TOTALS APPROACH 50 AND K INDICES CLIMB INTO THE 30S. WILL MENTION PATCHY FOG EARLY THIS MORNING...AGAIN LATE TONIGHT WITH MENTION OF SMALL CHANCE OF SHOWERS/ISOLATED THUNDER. DRY THIS EVENING. MARINE...STRONG THERMAL STABILITY REGIME OVER THE LAKES SHOULD LIMIT WINDS...PARTICULARLY GUSTS...AND KEEP WINDS BELOW HEADLINE CRITERIA THROUGH TONIGHT. LONG TERM...MONDAY THROUGH SATURDAY ON MONDAY MORNING THE ABOVE MENTIONED SHORTWAVE WILL BE MOVING NORTHEAST OF THE AREA. THIS WILL LEAVE MICHIGAN UNDER SHORTWAVE RIDGING AND NEGATIVE VORTICITY ADVECTION WHICH WOULD SUGGEST SUBSIDENCE FROM MID-MORNING ON. MODELS HOWEVER STILL INDICATING PLENTY OF INSTABILITY MAKING CHANCES FOR SHOWERS AND THUNDERSTORMS A CONCERN INTO THE AFTERNOON. NAM IS CONSIDERABLY OVERDONE WITH RESPECT TO LOW LEVEL MOISTURE BRINGING 70+ DEWPOINTS INTO THE TRI-CITIES WITH CAPES OF 2500 J/KG. THE GFS IS BETTER WITH DEWPOINTS IN THE MID 60S AND 1500 J/KG BUT MAY ALSO BE A BIT OVERDONE. MY FEELING IS THAT WE WILL NOT BE ABLE TO ACHIEVE THIS MUCH LOW LEVEL MOISTURE ADVECTION WITH THE SURFACE RIDGE STILL EXTENDING WESTWARD INTO SOUTHEAST MICHIGAN. MODIFIED GFS SOUNDINGS OF 80/62 YIELD ONLY 400 J/KG OF CAPE WITH WEAK CIN...POSSIBLY THE MOST REALISTIC SOLUTION. WILL GO AHEAD AND LEAVE CHANCE OF SHOWERS AND ISOLATED THUNDERSTORMS IN FOR THE MORNING AS THE WAVE IS EXITING THE AREA BUT WILL LEAVE MONDAY AFTERNOON AND TUESDAY DRY THINKING THAT MODELS ARE OVERDONE ON CHANCES FOR CONVECTION. BY MID-WEEK THE STRONG TROUGH CURRENTLY WORKING ITS WAY ONTO THE WEST COAST WILL BE PROPAGATING EASTWARD TOWARDS THE GREAT LAKES REGION. LOW PRESSURE WILL DEVELOP AT THE SURFACE IN THE LEE OF THE ROCKIES AND QUICKLY TRACK TOWARDS THE NORTHERN GREAT LAKES BY WEDNESDAY. MODELS HAVE STRUGGLED FOR DAYS WITH THE EVOLUTION OF THE SYSTEM...DEPENDING HEAVILY ON TIMING OF SHORTWAVES MOVING THROUGH THE TROUGH. 18Z/01 AND 00Z/02 GFS HAS TRENDED SLOWER THAN PREVIOUS RUNS...BRINGING THE FRONT THROUGH SE MICHIGAN DURING THE EVENING. THIS SOLUTION IS CLOSER TO THE ECMWF WITH ADDITIONAL SUPPORT FROM THE DGEX. WITH MODELS AGREEING THAT THE FRONT WILL NOT MOVE THROUGH THE AREA UNTIL THE EVENING HAVE REMOVED CHANCE OF PRECIPITATION FOR THE MORNING HOURS AND RAISED TEMPS 7-10 DEGREES FOR WEDNESDAY. FRONT STILL EXPECTED TO BE STRONG WITH 850MB TEMPS COOLING FROM ABOUT 15C TO -4C. WITH STRONG FRONTAL FORCING SHOWN FOR SEVERAL RUNS AND MODELS SHOWING BETTER AGREEMENT ON TIMING...HAVE RAISED POPS TO LIKELY FOR WEDNESDAY EVENING. STEEP LOW LEVEL LAPSE RATES WILL KEEP SKIES MOSTLY CLOUDY ON THURSDAY WITH CLOUDS EXPECTED TO CLEAR OUT THURSDAY NIGHT. STRONG SURFACE HIGH WILL APPROACH FROM THE WEST WITH GOOD RADIATIONAL COOLING CONDITIONS SETTING UP. WITH 850MB TEMPS OF -4C...WE COULD EASILY SEE MOST AREAS OUTSIDE OF THE DETROIT HEAT ISLAND DROPPING INTO THE MID TO UPPER 30S. FROST WILL BE A CONCERN...ESPECIALLY IF THE SURFACE HIGH SETS UP DIRECTLY OVERHEAD INCREASING COOLING POTENTIAL. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION...DWD SHORT TERM...DWD LONG TERM....KEK mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 855 PM EDT SUN OCT 2 2005 .SHORT TERM...TEMPS INLAND ARE FALLING A BIT FASTER THAN ORIGINALLY FCST IN AREAS WHERE WIND HAS DECOUPLED BUT SOME AREAS MAINTAINING AROUND 5 KT WITH TEMPS REMAINING UP. DEW POINTS NOT RECOVERING VERY QUICK INLAND AND GENERALLY REMAIN IN THE MID TO UPPER 50S. FCST LOWS NEAR 60 MAY WORK IN THE 57 TO 62 RANGE TONIGHT INLAND SO WILL NOT PLAN CHANGING FCST LOWS ATTM. LOW CLOUDS PUSHING WEST INTO COASTAL SECTIONS WHERE DEW POINTS ARE IN THE 60S AND TEMP WILL REMAIN MUCH HIGHER THAN INLAND. ISOLATED LIGHT SHOWERS OFF SHORE ALSO TRYING TO PUSH WEST BUT HAVING A DIFFICULT TIME. RUC NOT HANDLING THIS LIGHT PCPN VERY WELL BUT 18Z RUN OF GFS DID. CURRENT FCST OF SLIGHT CHANCE ALONG THE OUTER BANKS SHOULD HOLD MOST OF THE NIGHT BUT WILL NEED TO UPDATE FOR INCREASED LOW CLOUDS. && .AVIATION...VFR CONDITIONS INLAND MOST OF THE NIGHT SHOULD GIVE WAY TO MVFR CIGS BY DAY BREAK ALL BUT FAR INLAND SECTIONS. SOME MVFR VSBYS POSSIBLE ALONG THE COASTAL PLAIN. && .MARINE...BUOY AND CMAN REPORTS THIS EVENING CONTINUE TO INDICATE WINDS IN THE 15 TO 20 KT RANGE OVER THE COASTAL WATERS WITH SEAS VARYING FROM 3 TO 5 FT...HIGHEST AWAY FROM SHORE AND TO THE NORTH. EXPECT NE FLOW TO CONTINUE OVERNIGHT WITH PRIMARILY WIND WAVE GIVING WAY TO SWELL BY LATE MON. FOR NOW WILL MAINTAIN MENTION OF 3 TO 5 FT MOST AREAS. THIS WILL PRECLUDE MENTION OF LOWER NEAR SHORE SEAS ACROSS THE SRN WATERS WHERE WINDS ARE MOSTLY OFF SHORE. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS FOR AMZ150-152-154-156-158 FROM MIDNIGHT TUESDAY TO 8 PM FRIDAY. && $$ MLF nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 835 PM CDT SUN OCT 2 2005 FORECAST CHALLENGE CONCERNS MAINLY TEMPERATURES. COLD FRONT CURRENTLY ORIENTED ALONG A KROX-KABR LINE SHIFTING EAST 15-20 MPH AND SHOULD CLEAR FA AROUND 06Z. WEAK RETURNS AHEAD OF BOUNDARY OVER FAR SE FA HOWEVER SHORTLY WILL BE EAST OF FA. UPSTREAM CLOUD COVER IN WAKE OF BOUNDARY MAINLY HIGH CLOUD. LOW LEVEL COLD ADVECTION IN PROGRESS WITH GOOD LOW LEVEL DRYING IN WAKE OF FRONT. MINIMUM TEMPERATURE WILL BE CHALLENGE WITH BAROACLINIC ZONE ACROSS FA. CURRENT MINIMUMS LINING UP WELL WITH RUC SO AM NOT PLANNING ON ANY MAJOR CHANGES. OVERALL CHANGES TO UPDATE MINIMAL. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 1003 AM CDT SUN OCT 2 2005 .UPDATE...CONCERNS TODAY INVOLVE CLOUD TRENDS AND RESULTANT TEMPERATURES. LOW-LEVEL WARM AIR ADVECTION TO CONTINUE AHEAD OF COLD FRONT CURRENTLY POSITIONED ACROSS CENTRAL ND. 12Z RUC INDICATING SUFFICIENT 925MB MOISTURE COMBINED WITH WARM AIR ADVECTION TO PRODUCE OBSERVED LOW CLOUDS. THESE CONDITIONS TO CONTINUE THROUGH THE DAY BEFORE COLD FRONT SWEEPS THROUGH (W RED RIVER VALLEY BY MID-AFTERNOON...E RED RIVER VALLEY AFT 00Z). HEATING SHOULD DISSIPATE THESE CLOUDS SOME...BUT WILL NEED TO INCREASE CLOUD COVER AND THUS LOWER TEMPS 2F-4F. REMAINDER OF FORECAST IN GOOD SHAPE (INCLUDING WIND SPEEDS). UPDATE TO BE ISSUED BY 1030 AM. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 857 PM EDT SUN OCT 2 2005 .SHORT TERM (REST OF TONIGHT)... SURFACE HIGH PRES CONTINUES TO NOSE DOWN ACROSS THE REGION...WITH BETTER INSTABILITY AND SLIGHTLY DEEPER MOISTURE CONFINED SOUTH OF THE RIDGE ACROSS SRN GA. MODEL SOUNDINGS KEEP SOME DEGREE OF 900 TO 850 MB MOISTURE LOCKED IN ACROSS THE AREA ALONG WITH LIGHT EASTERLY UPSLOPE FLOW. THE RUC AND NAM AGREE THAT THE BEST LOW LEVEL MOISTURE POOL SHOULD AFFECT THE UPPER SAVANNAH RIVER AREA OVERNIGHT...WITH ABUNDANT CLOUDS CONTINUING TO FAN OUT ALONG AND EAST OF THE BLUE RIDGE. AN UPWARD ADJUSTMENT ON CLOUD COVER WILL BE THE MAIN CHANGE OVERNIGHT. FEATURED FORECAST TEMPS ARE WELL ABOVE THE COOL MAV NUMBERS FOR TONIGHT AT MOST LOCATIONS...AND THIS LOOKS VERY REASONABLE GIVEN EXPECTED CLOUD COVER. NO CHANGES TO TEMPERATURES ARE EXPECTED. && .PREVIOUS DISCUSSION... (ISSUED 257 PM EDT SUN OCT 2 2005) SHORT TERM (TONIGHT THROUGH WEDNESDAY)... HIGH PRESSURE OFF THE NEW ENGLAND COAST WILL CONTINUE TO BUILD INTO THE REGION THROUGH MONDAY. GFS AND NAM SLIGHTLY DIFFERENT IN THEIR HANDLING OF SURFACE LAYER MOISTURE...BUT TIME HEIGHTS MAKE A STRONG CASE FOR STRATUS DEVELOPMENT OVERNIGHT. MUCH OF THE UPSLOPE CUMULUS THAT DEVELOPED TODAY WILL DISSIPATE WITH THE LOSS OF HEATING...BUT WITH EASTERLY FLOW...WE MAY SEE STRATUS REDEVELOP LATE TONIGHT IN LIGHT UPSLOPE FLOW OVER THE STABLE SURFACE RIDGE. THIS REALLY DID NOT OCCUR LAST NITE UNTIL VERY LATE; HOWEVER...WE HAVE THE MOISTURE IN PLACE NOW AND MOISTURE MAY PICK UP AGAIN IN THE SOUTHERN CWFA LATE. WILL PLAN TO INCLUDE PATCHY DENSE MOUNTAIN VALLEY FOG...PATCHY FOG FOR THE MOUNTAINS AND PATCHY FOG FOR THE SOUTH CAROLINA/GEORGIA LAKES ADJACENT TO THE SAVANNAH RIVER. ELSEWHERE...A BIT OF WIND AND LESS THAN CLEAR SKIES LIKELY TO KEEP FOG ISOLATED. MONDAY LOOKING QUITE SIMILAR TO TODAY...BUT BOTH NAM AND GFS BRING A LOW LEVEL MOISTURE MINIMA OVER THE CWFA. THEY MAY BE A BIT TOO STRONG IN ERODING ANY UPGLIDE OVER THE SURFACE RIDGE...BUT WILL GO WITH JUST PARTLY CLOUDY FOR NOW WITH EAST TO NORTHEAST WINDS 5 TO 10 MPH. TEMPERATURES TONITE MID 50S NORTH TO MID 60S SOUTHWEST...WHERE DEWPOINTS HIGHER AND WHERE CLOUDINESS MAY LINGER THE LONGEST; WINDS ALSO LIKELY TO STAY UP LONGER THAN NORTHERN LOCATIONS. BASED ON TODAY...WE WENT WITH SLIGHTLY LOWER MAXES FOR MONDAY. CENTER OF UPPER RIDGE REMAINS VERY CLOSE TO CWFA TUE AND WED. CENTER OF SFC RIDGE CONTINUES TO SLOWLY MOVE EAST DURING THIS PERIOD...BUT RIDGING REMAINS OVER THE AREA. IT DOES WEAKEN A LITTLE WED. GENERAL EASTERLY LOW LEVEL FLOW REMAINS OVER THE AREA WITH A DECENT AMOUNT OF LOW LEVEL MOISTURE. HOWEVER...BEST MOISTURE REMAINS TO OUR EAST AS SOME DRY AIR AND SUBSIDENCE KEEP ANY PRECIP AT BAY. ALSO...MDLS SHOWING SOME WEAK ISENTROPIC LIFT AND/OR UPSLOPE...BUT PRECIP RESPONSE IN MDLS IS VERY LOW TO NIL. GIVEN RECENT CONDITIONS AND MDL FCSTS...LOOKS LIKE DRIER FCST IS IN STORE. HAVE GONE CLOSER TO MAV POP WHICH MEANS DRY MONDAY NIGHT...SLIGHT CHC SRN SECTIONS TUE/TUE NITE...AND LOW CHC SRN SECTION WED WITH SLIGHT CHC ELSEWHERE. WENT CLOSER TO MAV TEMP GUIDANCE THIS PERIOD AS MET TOO COOL ON LOWS AND HIGHS GIVEN LESS PRECIP AND MORE CLOUDS OVERNIGHT. && LONG TERM (WEDNESDAY NIGHT THROUGH SUNDAY)... PERSISTENT UPPER RIDGE FINALLY BREAKS DOWN THU INTO FRI AS SERIES OF SHORT WAVES DIG A TROF OVER THE EAST. SWLY FLOW DEVELOPS FRI AS SHORT WAVES CONTINUE TO DIG TOWARD THE AREA. WAVE SLOWLY TRANSLATES EAST OF THE AREA SATURDAY WITH NEARLY ZONAL FLOW FOR SUNDAY. AT THE SURFACE...MOIST ELY FLOW REMAINS OVER THE AREA AS FRONT APPROACHES THU. FNT MOVES ACROSS THE AREA FRIDAY. MOISTURE SLOWLY PULLS OUT SATURDAY WITH DRY HIGH PRESSURE BUILDING IN SUNDAY. ALL THIS MEANS INCREASING PRECIP CHANCES THU...NEARLY STEADY FRIDAY THEN DECREASING SATURDAY. DRY FCST SUNDAY. IF THIS SCENARIO CONTINUES...COULD BE A DECENT AMOUNT OF RAIN WITH THIS SYSTEM AND SOME THUNDER WITH THE FRONT. TEMPS NEAR TO A LITTLE ABOVE NORMAL THURSDAY...BELOW FRIDAY AND SATURDAY...THEN WARMING TO NEAR NORMAL SUNDAY. AVIATION... CONTINUED EASTERLY FLOW ABOVE THE HIGH PRESSURE RIDGE NOSING DOWN THE SOUTHERN APPALACHIANS SHOULD KEEP VFR CUMULUS CEILINGS IN PLACE UNTIL LOSS OF DAYTIME HEATING AND SETUP OF LOW LEVEL INVERSION OCCUR TOWARD EVENING. MODEL TIME HEIGHTS GIVE STRONG EVIDENCE THAT STRATUS WILL DEVELOP IN MOST PLACES OVERNIGHT...WITH DEEP MOISTURE NEAR THE SURFACE BELOW VERY DRY MID LEVEL AIR. STATISTICAL GUIDANCE KEEPS CEILINGS IN VFR RANGE OVERNIGHT AT ALL TAF SITES EXCEPT KAVL; HOWEVER...AFTER COLLABORATION WITH ZTL CWSU...WE WILL GO AHEAD AND ADVERTISE MVFR CEILINGS IN TEMPO GROUPS AT KCLT...KGSP...AND KGMU...AND ALSO AT KAND WITH POSSIBILITY OF MVFR VISIBILITY THERE. WE WILL ALSO FEATURE MVFR CEILINGS/VISIBILITIES AT KHKY...WITH TEMPO FOR IFR IN THE PREDAWN AT KAVL...WHICH HAS BEEN IN LIFR THE PAST FEW MORNINGS. OUTLOOK PERIOD MIXES OUT TO VFR ALL LOCATIONS BY 16Z...SIMILAR TO WHAT HAPPENED TODAY. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SHORT TERM...HG sc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MEMPHIS TN 1105 AM CDT SUN OCT 2 2005 .DISCUSSION...15 UTC SURFACE ANALYSIS THIS MORNING PLACES WARM FRONT ACROSS MISSOURI/ILLINOIS. SOUTH OF THE BOUNDARY SURFACE DEWPOINTS ARE IN THE UPPER 60 TO LOWER 70S. MAIN CONCERN FOR THIS AFTERNOON IS CONVECTIVE POTENTIAL. 12Z 850 MB UPPER AIR ANALYSIS INDICATED LOW LEVEL MOISTURE PLUME EXTENDING JUST WEST OF THE FORECAST AREA UP INTO WESTERN ONTARIO. 500 MB SHORTWAVE WILL CONTINUE TO MOVE THROUGH THE MID SOUTH THIS AFTERNOON. LAPS DATA SHOWS A WEAK INVERTED SURFACE TROUGH LOCATED NEAR THE TENNESSEE/MISSISSIPPI BORDER WITH THE ATMOSPHERE ALREADY BECOMING UNSTABLE AS NOTED BY VISIBLE SATELLITE. RUC MODEL SOUNDINGS APPEAR TO HAVE THE BEST HANDLE ON CONVECTIVE POTENTIAL THIS AFTERNOON. SURFACE BASED CAPES AROUND 2000 J/KG...LI/S AROUND -6...AND 700-500 MB LAYER LAPSE RATES AROUND 6 C/KM SUGGEST ANY THUNDERSTORMS THAT DO DEVELOP WOULD EXHIBIT PULSE TYPE CONVECTION TENDENCIES. THINK THAT BEST CHANCE OF SHRA/TSRA WILL BE PRIMARILY ALONG AND WEST OF THE MISSISSIPPI RIVER DELTA. WILL KEEP CONVECTION AS ISOLATED THIS AFTERNOON BUT WILL CONTINUE TO MONITOR CONVECTIVE TRENDS. WILL ISSUE AN UPDATE TO ADJUST TEMPERATURES/CLOUD COVER BASED ON CURRENT TRENDS. UPDATED GRIDS WILL BE PUBLISHED SHORTLY. CJC .PREV DISCUSSION...ISSUED 305 AM CDT SUN OCT 2 2005... A WARM FRONT OVER THE NORTHERN PART OF THE CWA WILL CONTINUE DRIFTING TO THE NORTH TODAY. A WARM AND HUMID AIRMASS IN PLACE WILL BE JUST UNSTABLE ENOUGH TO WARRANT A SLIGHT CHANCE OF THUNDERSTORMS THIS AFTERNOON THROUGH EARLY EVENING. AN UPPER LEVEL HIGH WILL DEVELOP OVER ARKANSAS TONIGHT AND MONDAY AND PERSISTS OVER THE REGION THROUGH EARLY WEDNESDAY. THIS WILL CONTINUE THE WARM WEATHER THROUGH THE FIRST HALF OF THE WEEK. SOME DIURNAL INSTABILITY WILL EXIST MON-TUE BUT NOT ENOUGH TO JUSTIFY 20 POPS AS THE HIGH WILL BE TOO STRONG. A COLD FRONT WILL MOVE THROUGH THE FCST AREA FROM THE NORTHWEST WEDNESDAY AFTERNOON AND EVENING. SHOWERS AND THUNDERSTORMS ARE POSSIBLE ALONG AND AHEAD THE FRONT. MUCH COOLER AND DRIER AIR WILL FOLLOW THE FRONT WEDNESDAY NIGHT THROUGH THE END OF THE FORECAST PERIOD AS A STRONG SFC HIGH TO THE NORTH INFLUENCES OUR WEATHER. SWC && .MEG WATCHES/WARNINGS/ADVISORIES... AR...NONE. MO...NONE. MS...NONE. TN...NONE. $$ tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 820 PM CDT SUN OCT 2 2005 .DISCUSSION...WATER VAPOR SATELLITE IMAGES AND 500MB RUC HEIGHT ANALYSIS INDICATES A RIDGE ACROSS THE EASTERN UNITED STATES EXTENDING INTO TEXAS AS MOISTURE FROM TROPICAL STORM OTIS NEAR SOUTHERN BAJA CALIFORNIA CONTINUES TO STREAM ACROSS NORTHWEST MEXICO INTO SOUTHEAST NEW MEXICO AND NORTHWEST TEXAS AHEAD OF THE LONGWAVE TROUGH ACROSS THE NORTHWEST UNITED STATES THIS EVENING. MSAS SURFACE ANALYSIS INDICATED HIGH PRESSURE OVER THE EASTERN U.S. EXTENDING INTO EAST TX AND THE NORTHERN GULF OF MEXICO WITH A TROUGH OF LOW PRESSURE OVER NORTHWEST TX. PRECIPITABLE WATER VALUES CONTINUE TO INCREASE ACROSS DEEP SOUTH TX WITH THE EASTERLY LOW TO MID LEVEL FLOW BRINGING TROPICAL MOISTURE OVER THE WESTERN GULF OF MEXICO WESTWARD. RADAR IMAGES INDICATE SCATTERED SHOWERS OVER THE WESTERN GULF OF MEXICO ADVECTING WESTWARD WITH THIS FLOW AND SHOULD MOVE INTO THE COASTAL SECTIONS OF THE CWA TONIGHT. AS TROPICAL STORM STAN OVER THE YUCATAN PENINSULA EMERGES INTO THE BAY OF CAMPECHE AND SOUTHWEST GULF OF MEXICO LATE TONIGHT...MOISTURE EXPECTED TO INCREASE ACROSS THE WESTERN GULF OF MEXICO AND SOUTH TX PROVIDING AN INCREASE IN CONVECTION TOWARDS THE MORNING INTO MONDAY. WITH PRECIPITABLE WATER VALUES OVER TWO INCHES...HEAVY RAINFALL POSSIBLE WITH THUNDERSTORMS MONDAY AFTERNOON. WILL LOWER POPS SLIGHTLY TONIGHT AND MENTION SHOWERS ONLY BASED ON LATEST RADAR TRENDS BUT RAIN CHANCES SHOULD INCREASE TOWARDS MORNING AS STAN EMERGES INTO THE SOUTHWEST GULF OF MEXICO. && .MARINE...WINDS THIS EVENING ARE GENERALLY EASTERLY AROUND 15 KNOTS AT 42020 AND 42002 WITH SEAS APPROXIMATELY 4 FEET. A MODEST INCREASE IN WINDS/WAVES IS EXPECTED AS T.S. STAN MOVES INTO THE BAY OF CAMPECHE ON MONDAY. SCATTERED TO NUMEROUS SHOWERS ARE EXPECTED AS WELL AS PWATS ARE PROGGED TO REMAIN ABOVE 2 INCHES OVER THE NW GULF OVER THE NEXT FEW DAYS. && .AVIATION...WATER VAPOR IMAGERY SHOWS T.S. STAN ADVECTING DEEP LAYER MOISTURE INTO THE NW GULF DURING THE DAY. THIS HAS LED TO AN INCREASE IN SHOWERS OVER THE MARINE AREA AND COASTAL COUNTIES TODAY. PERIODIC MVFR CONDS/SHOWERS AND ISOLATED THUNDERSTORMS ARE ANTICIPATED OVER THE NEXT 24 HOURS. OVERALL...LIGHT EASTERLY WINDS ARE EXPECTED. && .PREV DISCUSSION... /ISSUED 230 PM CDT SUN OCT 2 2005/ A HIGH PRESSURE RIDGE EXTENDING INTO THE RIO GRANDE VALLEY WILL CONTINUE PRODUCING LIGHT TO MODERATE EASTERLY WINDS ACROSS DEEP SOUTH TEXAS THROUGH TUESDAY. TROPICAL STORM STAN WILL MOVE WESTWARD ACROSS THE BAY OF CAMPECHE MONDAY AND TUESDAY. STAN WILL MOVE INTO THE SOUTH CENTRAL MEXICAN GULF COAST ON WEDNESDAY. AS THE STORM MOVES ACROSS THE SOUTHERN GULF OF MEXICO THE ATMOSPHERIC MOISTURE WILL INCREASE ACROSS THE CWA FOR THE NEXT FEW DAYS. THE ONSHORE EASTERLY WIND FLOW PATTERN AND A MOISTENING ATMOSPHERE WILL INCREASE THE CHANCES FOR SHOWERS AND THUNDERSTORMS ACROSS THE RIO GRANDE VALLEY MONDAY AND TUESDAY. AFTERNOON TEMPERATURES WILL DECREASE TO NEAR NORMAL VALUES FOR THIS TIME OF THE YEAR WITH AN INCREASE IN THE CLOUDINESS ACROSS THE AREA. A COLD FRONT WILL MOVE THROUGH DEEP SOUTH TEXAS EARLY THURSDAY MORNING SHIFTING WINDS TO THE NORTH AND REDUCING TEMPERATURES TO SLIGHTLY LOWER THAN NORMAL VALUES BY FRIDAY MORNING. IN THE WAKE OF THE COLD FRONT CLEAR TO PARTLY CLOUDY SKIES, LIGHT TO MODERATE NORTHERLY WINDS AND SLIGHTLY LOWER THAN NORMAL TEMPERATURES WILL PREVAIL ACROSS THE RIO GRANDE VALLEY FRIDAY THROUGH NEXT WEEKEND. && .BRO WATCHES/WARNINGS/ADVISORIES...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO 61/51 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 215 PM CDT SUN OCT 22005 .DISCUSSION...FORECAST FOCUS ON SCATTERED SHOWERS/ THUNDERSTORMS THIS EVENING...THEN ON NEAR RECORD HIGHS MONDAY AND TUESDAY AHEAD OF DEVELOPING STRONG LOW OVER FAR NW WI WEDNESDAY MORNING. WATER VAPOR AND RUC SHOW SHORTWAVE TROUGH AXIS NEAR MS RIVER AREA WILL MOVE ACROSS THE FORECAST AREA AND EXIT THE EAST LATE TONIGHT. AIRMASS HAS DESTABILIZED DUE TO EARLY SUNSHINE AND INCREASING MOISTURE. DEW POINTS NOW IN THE MID 60S RESULTING IN LI'S AROUND -4. THE INSTABILITY COMBINED WITH DYNAMIC LIFT OF SHORTWAVE HAS RESULTED IN THUNDERSTORMS INCREASING IN NUMBER AND INTENSITY THIS AFTERNOON. LOW LELEL HELICITY RATHER STRONG LATE THIS AFTERNOON AND EARLY EVENING...BUT WINDS ABOVE NOT SO STRONG. TEMPERATURES WILL REMAIN WARM INTO WEDNESDAY AS PERSISTENT SOUTHWEST FLOW AHEAD OF DEEP TROF DIGGING INTO NORTHWEST BRINGS SUMMER-LIKE TEMPERATURES FOR MON/TUE...AND NOW WITH THE SLOWER MOVEMENT WARM TEMPS INTO WEDNESDAY. WITH THE WARM 850 TEMPERATURES IN PLACE OVER REGION...TEMPERATURES WILL BE NEAR RECORDS. THE BIGGEST FORECAST PROBLEM IS WHETHER THE WARM SECTOR WILL BE DRY AS SURFACE LOW STRENGTHENS AND LOW LEVEL JET INCREASES. AT THIS MOMENT PREFER TO STAY MAINLY DRY UNTIL WEDNESDAY...AS WARM FRONT SHOULD BE TO THE NORTH. WITH THE SLOWER PROGRESSION OF THE SHORTWAVE...ANY FROST POTENTIAL PUSHED BACK 24 HOURS. NOW IF WINDS ON THE BACK SIDE OF THE LOW DECOUPLE FAST ENOUGH...FROST WILL BE POSSIBLE EARLY FRIDAY MORNING OVER SOUTH CENTRAL WISCONSIN...AND WITH SURFACE HIGH OVER THE AREA FRIDAY NIGHT AND SATURDAY...AGAIN ACROSS THE AREA EARLY SATURDAY MORNING...THOUGH LESS LIKELY ALONG THE LAKE COUNTIES AS LAKE WATER TEMPS/850 MB TEMP DIFFERENCE AND NE FLOW WILL BRING STRATUS INLAND AS WELL AS SLIGHTLY WARMER TEMPS THAN OVER SOUTH CENTRAL. && .MKX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ HENTZ wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 1013 AM CDT SUN OCT 2 2005 .UPDATE... FOR NOW NO FORECAST UPDATES NEEDED. THOUGH WILL KEEP AN EYE ON TEMPERATURES OVER FORECAST AREA...AS IT LOOKS LIKE MORE CLOUDS THAN SUN AT THIS TIME. SHORTWAVE TROUGH OVER WESTERN IOWA CONTINUES TO TRACK NORTHEAST INTO FORECAST THIS AFTERNOON. SHOWERS HAVE BEGUN TO DEVELOP UNDER ACCAS FIELD OVER CLAYTON AND ALLAMAKEE COUNTIES IN NORTHEAST IOWA. THIS IS IN RESPONSE TO GOOD 850MB MOISTURE TRANSPORT VECTORS INDICATED BY THE RUC AND LAPS AT 14Z. SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER EASTERN FORECAST AREA LATE THIS MORNING AND THIS AFTERNOON. SEVERE THREAT LOOKS MINIMAL AND ISOLATED OVER EASTERN FORECAST AREA. LATEST 12Z NAM AND RUC INDICATE MOST UNSTABLE CAPE AROUND 2000 J/KG AND 0-3 KM SHEAR OF 30 TO 35 KNOTS BETWEEN 18-21Z. DTJ && .PREV DISCUSSION... .SHORT TERM...THROUGH TUESDAY MAIN FORECAST CONCERNS ARE WITH THE RAIN CHANCES TODAY AND TONIGHT AND THEN AGAIN BY TUESDAY. SURFACE ANALYSIS EARLY THIS MORNING SHOWS AN AREA OF LOW PRESSURE OVER WESTERN NORTH DAKOTA WITH A WARM FRONT ACROSS SOUTHERN CANADA. COLD FRONT EXTENDS SOUTHWEST FROM THE LOW INTO WYOMING. THE 00Z MODELS APPEARED TO BE INITIALIZED FAIRLY WELL WITH NO MAJOR PROBLEMS NOTED. MODELS IN FAIRLY GOOD AGREEMENT WITH THE MASS FIELDS FOR THE SYSTEM TO AFFECT THE UPPER MIDWEST TODAY AND TONIGHT. SOME TIMING DIFFERENCES WITH THE SPEED OF THE SYSTEM COMING IN TUESDAY AND HAVE LEANED TOWARD THE SLOWER GFS SOLUTION. SATELLITE SHOWS THE UPPER LEVEL THAT HAS BEEN OVER THE SOUTHERN PLAINS IS NOW PROGRESSING NORTHEAST AND IS OVER THE KMCI AREA. THIS SYSTEM WILL CONTINUE TO TRACK NORTHEAST TODAY AS THE LONG WAVE TROUGH OVER THE WESTERN PART OF THE COUNTY CONTINUES TO DEEPEN TO AMPLIFY THE OVERALL FLOW. WITH THE EXPECTED PATH OF THE SYSTEM... THE BEST FORCING WILL OCCUR OVER THE EASTERN SECTIONS OF THE FORECAST AREA AND HAVE CONTINUED THE HIGHER POPS FOR THIS REGION. SYSTEM WILL CONTINUE TO WEAKEN AS IS WORKS UP AGAINST THE RIDGE OVER THE EASTERN PART OF THE COUNTRY AND THE FORCING DOES NOT APPEAR STRONG ENOUGH TO PRODUCE WIDESPREAD COVERAGE SO HAVE KEPT THE POPS IN THE CHANCE RANGE. THE NAM IS STILL SHOWING SURFACE AND ELEVATED CAPE VALUES UP TO 1000 J/KG TO SUPPORT THE POSSIBILITY OF SOME THUNDER. OTHER CONCERN WITH THIS SYSTEM IS THE TEMPERATURES FOR TODAY. SATELLITE IS CURRENTLY SHOWING MAINLY SCATTERED TO OCCASIONALLY BROKEN CLOUDS OVER THE FORECAST AREA...WITH THE MORE EXTENSIVE CLOUD COVER FROM SOUTHERN IOWA INTO MISSOURI. TEMPERATURES HAVE NOT COOLED MUCH WITH MOST LOCATIONS STILL IN THE LOWER TO MIDDLE 60S. BUMPED HIGHS FOR TODAY UP A LITTLE ACROSS THE NORTH WITH THE WARM START AND WITH THE DEEPER CLOUD COVER BEING SLOWER TO ARRIVE. CLOUDS BEHIND THIS SYSTEM EXPECTED TO REMAIN IN PLACE THROUGH THE NIGHT. TIME/HEIGHT PLOTS SHOW VERY HIGH RELATIVE HUMIDITY VALUES BELOW 800 MB AND THE NAM SHOWS AROUND 2 UBAR/S OF UPGLIDE ON THE 305K ISENTROPIC SURFACE. THIS SHOULD HELP TO PRODUCE AN AREA OF LOW CLOUDS SIMILAR TO WHAT IS OCCURRING THIS MORNING ACROSS EASTERN NEBRASKA AND KANSAS. ATTENTION THEN SHIFTS TO THE SYSTEM TO AFFECT THE REGION STARTING TUESDAY. THE LONG WAVE TROUGH OVER THE WESTERN U.S. WILL CROSS THE ROCKIES AND ENTER THE UPPER MIDWEST LATE TUESDAY. THE FRONT CURRENTLY ACROSS THE HIGH PLAINS WILL REMAIN NORTH AND WEST OF THE FORECAST AREA UNTIL THE UPPER LEVEL SYSTEM STARTS TO KICK IT EAST. THE GFS WOULD SUGGEST THE FRONT SHOULD EXTEND FROM NEAR LAKE SUPERIOR ACROSS MINNESOTA INTO NEBRASKA BY LATE TUESDAY. AS FORCING FROM THE APPROACHING UPPER LEVEL SYSTEM INCREASES...COULD SEE SOME SHOWERS AND STORMS AFFECT THE FAR WESTERN SECTIONS LATE TUESDAY. UNTIL THEN...THE REGION WILL STAY IN THE WARM SECTOR HELPING TO KEEP WELL ABOVE NORMAL TEMPERATURES IN PLACE. 850 MB TEMPERATURES ON THE GFS INCREASE TO AROUND 18C BY LATE MONDAY AFTERNOON AND REMAIN THERE THROUGH TUESDAY. NO CHANGES MADE TO THE HIGHS FOR MONDAY BUT DID RAISE VALUES FOR TUESDAY. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY THE UPPER LEVEL SYSTEM AND COLD FRONT ARE EXPECTED TO DRIVE ACROSS THE UPPER MIDWEST TUESDAY NIGHT AND WEDNESDAY. STRONG DYNAMICAL FORCING EXPECTED TO OCCUR WITH THIS SYSTEM WITH THE GFS TIME/HEIGHT PLOTS SHOWING THE LIFT TO BE AROUND 5 UBAR/S TUESDAY NIGHT. THE BEST 0-6 KM SHEAR REMAINS BEHIND THE FRONT...BUT THERE DOES APPEAR TO BE A DECENT AMOUNT OF 0-3 KM SHEAR AVAILABLE WITH THE GFS SHOWING VALUES OF 30 TO 35 KNOTS JUST AHEAD OF THE FRONT. WITH THE LINEAR FORCING SIGNAL THREAT WOULD APPEAR TO BE A THREAT FOR STRAIGHT LINE WINDS AS A SQUALL LINE DEVELOPS. HIGH PRESSURE SETTLES IN OVER THE REGION FOR THURSDAY AND WILL USHER IN ANOTHER ROUND OF OVERNIGHT LOWS IN THE 30S. MASSAGED TEMPERATURES A LITTLE ACROSS THE EASTERN SECTIONS TUESDAY NIGHT AND WEDNESDAY AS THESE AREAS WILL REMAIN IN THE WARMER AIR THE LONGEST. THEN LOWERED TEMPERATURES SOME BOTH WEDNESDAY NIGHT AND THURSDAY WITH THE 850 MB RIDGE REMAINING WEST OF THE AREA HELPING TO MAINTAIN COLD AIR ADVECTION ACROSS THE FORECAST AREA. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ 04 wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GOODLAND KS 202 AM MDT MON OCT 3 2005 .DISCUSSION...FORECAST CHALLENGE IS TEMPERATURES THE NEXT SEVERAL DAYS AS 90 DEGREE TEMPERATURES TODAY WILL BE BUT JUST A MEMORY COME WEDNESDAY AS A STRONG COLD FRONT MOVES THROUGH THE NORTHERN AND CENTRAL PLAINS LATE IN THE DAY TUESDAY. TOUGHEST PART OF THE FORECAST REMAINS ON FRONTAL TIMING AS THE NAM IS ISOLATED IN ITS SOLUTION (QUICKER) WHEN COMPARED TO THE REMAINDER OF SHORT RANGE MODELS. HOWEVER...THE NAM HAS A KNACK FOR NAILING THESE EVENTS SO ITS SOLUTION CANNOT BE TOTALLY RULED OUT. AT 08Z LOCAL RADAR MOSAIC SHOWING A COLD FRONT EXTENDING FROM CENTRAL NEBRASKA SOUTHWEST INTO YUMA COUNTY COLORADO THEN TOWARD LIMON. LATEST 06Z RUC AND 00Z NAM HAVE THE WINDSHIFT HANDLED WELL AND HAVE BLENDED BOTH IN THE SHORT TERM. TEMPERATURES RANGE FROM 57 DEGREES IN FLAGLER (EASTERN COLORADO) TO 77 DEGREES IN HILL CITY KANSAS. HILL CITYS NORMAL HIGH TODAY IS 77. TODAY/TONIGHT...SOUTH WINDS WILL REDEVELOP ACROSS THE AREA TODAY AS THIS MORNINGS COLD FRONT MOVES BACK NORTH. CIRRUS ASSOCIATED WITH A DISTURBANCE CAUGHT IN THE UPPER FLOW WILL QUICKLY MOVE NORTHEAST TODAY...LEAVING A SUNNY/MOSTLY SUNNY SKY. 850 TEMPERATURES AS WELL AS 2M/MOS GUIDANCE NUMBERS ALL SUPPORT HIGHS AGAIN IN THE 90S. NEAR RECORD TEMPERATURES WILL BE MENTIONED FOR GOODLAND (93)...BURLINGTON COLORADO (92) AND COLBY KANSAS (94). ANOTHER UPPER DISTURBANCE MOVES ACROSS THE AREA FROM THE SOUTHWEST TONIGHT...SPREADING HIGH LEVEL CLOUDINESS BACK INTO THE AREA. THE COLD FRONT WILL AGAIN PUSH SOUTH AND INTO THE AREA GENERALLY BISECTING THE AREA FROM NORTHEAST TO SOUTHWEST. DEWPOINTS WILL BE IN THE 60S GENERALLY ON THE EAST SIDE OF THE BOUNDARY SO MUCH ABOVE NORMAL MINS EXPECTED WHILE SLIGHTLY COOLER CONDITIONS TO THE WEST OF THE BOUNDARY. TUESDAY/TUESDAY NIGHT...GENERAL CONSENSUS AMONGST THE GFS/NGM/RUC/UKMET IS TO KEEP THE FRONT TO OUR NORTH THROUGH THE DAY WHILE THE NAM BULLS ITS WAY SOUTH AND IS THE ONLY SOLUTION TO DO SO. EITHER WAY...SOME SLIGHT COOLING AT 850 IS NOTED BY THE MODELS BY SOME 3-5F. WILL AGAIN SEE SOME CIRRUS WITH THE EXACT POSITION AHEAD OF THE UPPER TROUGH IN QUESTION. FRONT WILL BLOW THROUGH THE AREA TUESDAY NIGHT WITH SUFFICIENT MOISTURE AND DYNAMICS TO MAINTAIN A SMALL CHANCE OF PRECIPITATION..MAINLY WEST THROUGH NORTH/NORTHEAST PER GFS SOLUTION. WILL KEEP SLIGHT CHANCE TUESDAY NIGHT AND PRETTY MUCH END THINGS BY OR SHORTLY AFTER MIDNIGHT AS BETTER MOISTURE AND LIFT ALONG WITH FRONT WILL BE QUICKLY EXITING THE AREA. WEDNESDAY/WEDNESDAY NIGHT...MUCH COLDER AIR POURS INTO THE AREA DURING THE DAY WITH AFTERNOON TEMPERATURES ABOUT 30 DEGREES COLDER THEN TUESDAYS READINGS. THE AXIS OF HIGH PRESSURE REMAINS ACROSS THE AREA WEDNESDAY NIGHT...PROMISING LITTLE RETURN FLOW FROM THE SOUTH TO OFFSET OR WARM OVERNIGHT READINGS. 2M/MOS GUIDANCE NUMBERS ARE ALL IN THE 30S AND AN INCREASED THREAT FROM FROST OR FREEZE IS EXPECTED TO COVER MUCH MORE OF THE FORECAST AREA. THURSDAY...SURFACE HIGH STILL INFLUENCING THE AREA WITH 850 TEMPERATURES A FEW DEGREES COLDER THEN WEDNESDAYS READINGS. LATEST DGEX/GFS HAVE AN EAST WIND SO SIMILAR OR SLIGHTLY COOLER READINGS LOOKS LIKE A GOOD BET. LATEST MEX GUIDANCE HAS A GOOD HANDLE ON THINGS AS WELL SO BROUGHT HIGHS DOWN CLOSE TO 60 OR SO. FRIDAY-SUNDAY...A WARMING TREND TAKES PLACE AS 850 TEMPERATURES WARM QUITE A BIT EACH DAY UNDER GRADUAL WEST COAST TROUGHING. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. NE...NONE. CO...NONE. && $$ DDT ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 425 AM EDT MON OCT 3 2005 .DISCUSSION... MAIN FCST ISSUES ARE PCPN CHANCES TODAY THRU MIDWEEK. WATER VAPOR IMAGERY AND RUC ANALYSIS SHOW HIGH AMPLITUDE PATTERN OVER THE CONUS. A DEEP TROF WAS ALONG THE W COAST WITH A STRONG MIDLEVEL LOW OVER SASKATCHEWAN RIDING ENE AROUND PERIPHERY OF AN IMPRESSIVE RIDGE DOMINATING THE ERN CONUS/SE CANADA. A SHORTWAVE CURRENTLY LIFTING NE THRU ERN UPPER MI/LWR MI HAS PRODUCED SCT SHRA AND A FEW TSRA OVER SCNTRL/ERN UPPER MI DURING THE NIGHT. EXPECT THIS ACTIVITY TO BE MOSTLY OUT OF THE CWA BY FCST ISSUANCE TIME. MEANWHILE...PERSISTENT SW FLOW HAS BROUGHT CONSIDERABLE MOISTURE N INTO THE MIDWEST/WRN GREAT LAKES. PRECIPITABLE WATER AT KGRB/KMPX/KINL/KDVN WAS RUNNING IN THE 1-1.7 INCH RANGE OR 190-230PCT OF NORMAL. IN ADDITION...WATER VAPOR IMAGERY SHOWS A PLUME OF TROPICAL MOISTURE STREAMING THRU THE PLAINS...CONNECTED TO ONCE HURRICANE OTIS NEAR THE BAJA. AT THE SFC...DWPTS LOOKED VERY SUMMERLIKE WITH MID 60S TO AROUND 70F COMMON FROM KS/MO ACROSS IA/IL/MN/WI. 08Z TEMP AT KIWD WAS STILL 72F...IS IT REALLY OCT? TO THE W...COLD FRONT EXTENDS FROM LOW PRES OVER FAR NE MANITOBA S THRU WRN MN TO FAR SE SD AND INTO NEBRASKA. PROGRESS OF THIS FRONT WILL BE CRITICAL TO PCPN POSSIBILITIES PRIOR TO STRONG SHORTWAVE ARRIVING MIDWEEK. ALSO...THE ABUNDANCE OF MOISTURE INDICATES POTENTIAL FOR HVY RAINFALL NEAR FRONTAL BOUNDARY. NAM CONTINUES TO BE MOST AGGRESSIVE IN PUSHING COLD FRONT SLOWLY THRU THE AREA LATE TONIGHT THRU TUE AND STALLING JUST S OF UPPER MI. THIS WOULD SET THE STAGE FOR MDT TO POTENTIALLY HEAVY RAINFALL OVER MOST OF THE FCST AREA AS STRONG SHORTWAVE APPROACHES LATE TUE INTO WED. THE NAM IS ON ITS OWN AS GFS/CANADIAN/UKMET HOLD FRONT UP OVER THE NW PART OF UPPER MI OR EVEN SLIGHTLY FARTHER W PER CANADIAN. GIVEN STRENGTH OF UPPER RIDGE CURRENTLY DOMINATING THE ERN CONUS... WILL FAVOR THE CONSENSUS SOLUTION WHICH HOLDS UP FRONT OVER NW UPPER MI PRIOR TO STRONG SHORTWAVE ARRIVAL MIDWEEK. GFS FCST SOUNDINGS SUGGEST MOST OF THE AREA SHOULD BE CAPPED TODAY... PREVENTING SFC BASED CONVECTIVE DEVELOPMENT. IN ADDITION...LOW-LEVEL FLOW IS ANTICYLONIC AND HEIGHTS RISE SLIGHTLY. HOWEVER...TO THE W...WITH COLD FRONT SLIPPING E OVER WRN LAKE SUPERIOR...CAN'T RULE OUT SOME CONVECTION DEVELOPING JUST AHEAD OF FRONT WITHIN THETA-E RIDGE. THUS...SEE NO REASON TO DEVIATE FROM THE GOING FCST WHICH HAS SLIGHT CHC POPS OVER THE W THIRD TODAY. WITH 850MB TEMPS SIMILAR TO YESTERDAY...EXPECT HIGHS TO BE SIMILAR...PROVIDED CLOUD COVER DOESN'T BECOME TOO WIDESPREAD. WILL GO WITH MID 70S TO AROUND 80 MOST AREAS...WITH READINGS AROUND 70 NEAR LAKE MICHIGAN. EXPECT RECORD OF 73 HERE AT THE OFFICE TO FALL EASILY. TONIGHT AND TUE...DEVELOPMENT OF STRONGLY CONFLUENT FLOW ACROSS MANITOBA/NRN ONTARIO WILL BE THE KEY FACTOR IN PROGRESSION OF COLD FRONT. STRONG CONFLUENCE WILL SUPPORT BUILDING HIGH PRES TO THE N AND AN INFLUX OF COLD AIR SE ACROSS MANITOBA/ONTARIO. RESULT WILL BE STRENGTHENING AND TIGHTENING BAROCLINIC ZONE ASSOCIATED WITH FRONT...WHICH WILL BE FORCED VERY SLOWLY SE BY THE INCREASING SFC PRES ACROSS ONTARIO. THIS COMBINED WITH THE ABUNDANCE OF MOISTURE TO THE S SUGGESTS AN INCREASING POTENTIAL FOR HEAVY RAINFALL NEAR THE FRONT. WITH FRONT SLIPPING SE TO FAR WRN UPPER MI...WILL CONTINUE TO CARRY PCPN CHANCES OVER THE W TONIGHT...BUT WILL HOLD OFF ON LIKELY POPS FOR NOW DUE TO SOME UNCERTAINTY ON HOW FAR SE FRONT WILL DRIFT TONIGHT. WILL STAY WITH A DRY FCST CNTRL/E. WILL BE UNSEASONABLY WARM AGAIN WITH MINS AT OR ABOVE NORMAL HIGH TEMPS FOR THIS TIME OF YEAR DUE TO UNUSUALLY WARM/MOIST AIRMASS. EXPECT FRONT TO HANG UP FROM NEAR KIWD TO NEAR KMQT ON TUE PER GFS/UKMET. STRENGTHENING UPPER JET ACROSS NRN ONTARIO/QUEBEC WILL IMPROVE BROAD UPPER DIVERGENCE FIELD OVERTOP FRONTAL BOUNDARY. AT THE LOW-LEVELS... FRONTOGENESIS INCREASES BTWN 925-800MB OVER THE NW HALF OF FCST AREA (ALONG JUST BEHIND SFC FRONT) WITH INCREASING LOW-LEVEL INFLOW ACROSS SFC FRONTAL BOUNDARY. WILL UP POPS INTO THE LIKELY RANGE OVER THE FAR WRN COUNTIES AND BRING CHC POPS INTO THE CNTRL (ROUGHLY AS FAR E AS KIMT TO MUNISING). LATER FCSTS MAY NEED TO RAISE POPS TO CATEGORICAL OVER THE W IF CONFIDENCE ON POSITION OF FRONT INCREASES. WILL ALSO NEED TO WATCH CLOSELY THE POTENTIAL FOR HEAVY/EXCESSIVE RAINFALL GIVEN ABUNDANCE OF MOISTURE (PRECIPITABLE WATER AROUND 1.75 INCHES OR 250-300PCT OF NORMAL FOR UPPER MI) WITH TROPICAL CONNECTION AND DEEP WARM CLOUD LAYER AROUND 14KFT PER GFS FCST SOUNDINGS. STRONG SHORTWAVE EMERGING OUT INTO THE WRN PLAINS TUE NIGHT WILL LEAD TO SFC LOW PRES LIFTING NE TO CNTRL MN BY 12Z WED. STRENGTHENING LOW-LEVEL JET (850MB WINDS 40-50KT) IN RESPONSE TO APPROACHING SHORTWAVE WILL WORK TO PUSH FRONTAL BOUNDARY BACK TO THE N TUE NIGHT/WED. DIFFICULT TO KNOW HOW QUICK OR HOW FAR N FRONT WILL MOVE...ESPECIALLY WITH EXTENSIVE CONVECTION ALONG IT...AND THAT WILL BE VERY IMPORTANT TO PCPN FCST AND POTENTIAL FOR EXCESSIVE RAINFALL IN UPPER MI. AT THE MOMENT...WOULD APPEAR THAT HEAVIEST RAINFALL WILL BE JUST NW AND N OF FCST AREA ALONG AND JUST N OF SHARP 850MB FRONT FROM NEAR KDLH TO NCNTRL LAKE SUPERIOR. AGAIN... WILL BE SOMETHING TO WATCH CLOSELY GIVEN THE ABUNDANCE OF MOISTURE AVAILABLE. WILL KEEP POPS ALIGNED TUE NIGHT IN A SIMILAR WAY TO THE TUE PERIOD. DESPITE HAVING A SIMILAR PROGRESSION OF SHORTWAVE... UKMET/CANADIAN/GFS HAVE QUITE DIFFERENT TIMING FOR SFC LOW. BY 00Z THU...UKMET IS SLOWEST WITH SFC LOW IN NW MN...CANADIAN IS IN THE MIDDLE OVER WRN LAKE SUPERIOR WHILE GFS IS FASTEST WITH SFC LOW OVER ERN LAKE SUPERIOR. GIVEN THE UNCERTAINTY...WILL CONTINUE ALONG THE LINES OF GOING FCST (WHICH IS SIMILAR TO GFS) AND SPREAD LIKELY POPS W TO E ON WED. WILL BECOME WINDY BEHIND SYSTEM WED NIGHT/THU IN STRONG CAA REGIME WITH POTENTIAL GALES ON LAKE SUPERIOR...AND STILL LOOKS LIKE THERE WILL BE SOME SNOW MIXED WITH THE RAIN SHOWERS IN DEVELOPING LAKE EFFECT REGIME WED NIGHT THRU THU NIGHT. WON'T BE THE FIRST SNOW FLAKES TO FALL IN THE U.P. THIS FALL SINCE SOME SNOW BRIEFLY FELL IN THE EARLY MORNING HRS OF SEPT 29TH IN ALGER COUNTY. GOING FCST MIGHT BE A BIT QUICK TO BRING MIXED PCPN INTO THE AREA WED NIGHT BASED ON UKMET/CANADIAN. WILL LET NEXT SHIFT REEVALUATE POTENTIAL BASED ON 12Z RUNS. && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 112 AM EDT MON OCT 3 2005 .AVIATION... CONCERNS REGARDING FOG AND THE CHANCE OF THUNDERSTORMS WILL IMPACT AVIATION INTERESTS THROUGH ABOUT NOON TODAY. THE LEADING EDGE OF HIGHER MOISTURE IN THE MID LEVELS APPEARS TO BE RESIDING OVER SW LOWER MICHIGAN, ASSOCIATED WITH THE SHORT WAVE MOVING THROUGH THE AREA, AT LEAST JUDGING BY RADAR IMAGERY AND 00Z MODEL ANALYSIS FIELDS. THIS IS WHERE NEW DEVELOPMENT OF SCATTERED SHOWERS AND ISOLATED STORMS WILL BE FAVORED AND AFFECTING THE MBS AND FNT TERMINALS MORE THAN DTW AND DET, ALTHOUGH PRECIP CAN'T BE RULED OUT THERE AS WELL FOR THE SAME REASONS BUT WITH A LITTLE BOOST FROM AN MCV LEFT OVER FROM EARLIER YESTERDAY. HOWEVER, THE BEST CHANCE OF THUNDERSTORMS WILL BE AROUND THE TRI CITIES WHERE THE BEST COMBINATION OF MOISTURE ADVECTION, STEEPER MID LEVEL LAPSE RATES, AND MODEST SUPPORT FROM THE FILLING WAVE COME TOGETHER. INCREASING SURFACE DEWPOINT WILL BE THE DRIVING FACTOR BEHIND FOG BEFORE SUNRISE. SOUTH WIND IS EXPECTED TO STAY IN THE 5 TO 10 KNOT RANGE AND MINIMIZE RADIATIONAL COOLING, ALONG WITH CLOUD COVER, BUT SURFACE DEWPOINT RISING INTO THE MID AND UPPER 60S WILL RESULT IN AT LEAST AREAS OF MVFR FOG AS THE LONGER NIGHT UNFOLDS. EXPECT THE FOG TO LIFT SLOWLY AND THE PRECIP POTENTIAL TO DIMINISH DURING THE MORNING, FOLLOWED BY DRY AND VFR CONDITIONS THIS AFTERNOON AND THIS EVENING. && .PREV DISCUSSION... (ISSUED 940 PM EDT SUN OCT 2 2005) UPDATE... THE MAIN CONCERN FOR THE OVERNIGHT HOURS WILL BE COVERAGE OF SHOWERS AND THUNDERSTORMS. STILL ANTICIPATING A TRANSITION FROM SURFACE BASED CONVECTION TO ELEVATED AS THE NIGHT WEARS ON. THE LATEST RUC ANALYSIS FIELDS DEPICT FAIRLY WELL THE COMBINATION OF LOW LEVEL MOISTURE ADVECTION AND SHORT WAVE SUPPORT THAT IS ONGOING AND RESPONSIBLE FOR THE CURRENT PATTERN OF SHOWERS AND STORMS. THE COMBINATION OF THETA-E ADVECTION BELOW 700 MB AND DCVA FROM THE WAVE FAVORS LOCATIONS MAINLY NORTH AND WEST OF DETROIT FOR NEW SHOWER AND STORM DEVELOPMENT OVERNIGHT AND MONDAY MORNING. OUR GOING FORECAST IS IN GOOD SHAPE. THE THEME OF THE UPDATE WILL BE TO ADD SOME CONFIDENCE WITH AREAL COVERAGE TERMS RATHER THAN CHANCE TERMS IN THE PRECIP FORECAST AROUND FLINT AND THE TRI CITIES, NOW THAT WE HAVE ACTIVITY ON RADAR. WE'LL ALSO USE THIS UPDATE TO FRESHEN UP SOME OF THE OTHER ELEMENTS. THE TEMP FORECAST LOOKS GOOD BUT WITH READINGS EXPECTED TO COME IN NEAR THE WARM END OF THE RANGE. PREV DISCUSSION... (ISSUED 308 PM EDT SUN OCT 2 2005) SHORT TERM...TONIGHT AND MONDAY WARM AND HUMID AIR CONTINUES TO SURGE NORTH INTO SOUTHER LOWER MICHIGAN THIS AFTERNOON...AS SURFACE DEW POINTS HAVE RISEN IN THE LOW TO MID 60S. UNLIKE MUCH OF THE SUMMER...THE MODELS ARE NOT OVERESTIMATING THE LOW LEVEL MOISTURE. ADDITIONAL LOW LEVEL MOISTURE WILL SPREAD INTO THE REGION THROUGH TONIGHT...AS DE-AMPLIFYING SHORTWAVE TROUGH OVER THE MIDWEST/WESTERN GREAT LAKES REACHES THE ONTARIO/QUEBEC BORDER MONDAY MORNING. MAIN FORCING WITH THIS SYSTEM WILL BE NORTH OF SOUTHEAST MICHIGAN. NONE-THE-LESS...ENOUGH SOUTHWARD EXTENSION/INSTABILITY/TROUGHINESS TO CONTINUE WITH CHANCE POPS...BEST CHANCE ACROSS TRI-CITIES REGION TONIGHT. SOUTHEAST MICHIGAN WILL REMAIN IN A MOIST AND UNSTABLE AIRMASS TOMORROW...AS SURFACE DEW POINTS CONTINUE TO HOVER WELL INTO THE 60S. WITH SHORTWAVE RIDGING EXPECTED DURING THE AFTERNOON HOURS AND A LACK OF A TRIGGER...WILL KEEP THE FORECAST DRY DURING THE AFTERNOON HOURS. ALTHOUGH THERE IS SOME DECENT INSTABILITY INDICATED (CAPES OVER 1000 J/KG ALONG WITH LI'S OF -3 C OR BETTER)...THE CAPE IS SKINNY AND THERE IS SUFFICIENT LOW LEVEL CIN (25-50 J/KG). CU RULES POINTING TO SCT-BKN CLOUD COVER. WITH PARTIAL SUNSHINE AND 925 MB TEMPS RUNNING AROUND 23 C...MAX TEMPS SHOULD EASILY CLIMB INTO THE LOW TO MID 80S. KEEP IN MIND...RECORD HIGHS ARE IN THE UPPER 80S FOR EARLY OCTOBER. LONG TERM...MONDAY NIGHT THROUGH SUNDAY THE TRANSITION OF THE SEASONS IS DEFINITELY THE CHALLENGE IN THE FORECAST FOR THE UPCOMING WEEK. THE WEATHER FOR THE FIRST HALF OF THE WEEK (INCLUDING TUESDAY/WEDNESDAY OF THE LONG TERM FORECAST) WILL BE RATHER SUMMER-LIKE. TEMPERATURES LOOK TO CLIMB INTO THE LOWER TO MID 80S OVER MUCH OF THE AREA ON TUESDAY...AND PERHAPS AGAIN ON WEDNESDAY DEPENDING ON THE TIMING OF A STRONG COLD FRONT. THE TREND TO A SLOWER PROGRESSION OF STRONG UPPER LEVEL STORM AND SAID FRONT CONTINUES IN THE 12Z RUNS...WHICH BODES WELL FOR ANOTHER WARM DAY. WILL KEEP TEMPERATURES AT OR JUST SHORT OF 80 (A SOLID 15 DEGREE ABOVE NORMAL FOR EARLY OCTOBER)...DUE TO THE POTENTIAL FOR INCREASED CLOUD COVER AND SHOWER/THUNDERSTORM ACTIVITY DURING THE LAST HALF OF THE DAY. ANY ADDITIONAL DELAY IN THIS SYSTEM MAY WARRANT AN EVEN WARMER FORECAST ON WEDNESDAY. THEREAFTER...COLD FRONT BLOWS THROUGH LOWER MICHIGAN WEDNESDAY NIGHT. MUCH COOLER CONDITIONS THEN SET UP ON THURSDAY/FRIDAY WITH A SLOW MODERATION INTO NEXT WEEKEND. DID NOT CHANGE MUCH IN THE FORECAST DURING THIS TIME-FRAME AS TEMPERATURES STRUGGLE TO REACH 60...AND LIKELY WILL NOT IN MANY AREAS. THIS BOUT OF COOL WEATHER WILL BE OF A LONGER DURATION THAN LAST WEEKS SYSTEM AS SPRAWLING HIGH PRESSURE SLOWLY SETTLES INTO THE GREAT LAKES FROM THURSDAY INTO THE WEEKEND. THIS WILL NOT ONLY KEEP HIGH TEMPERATURES AOB 60 THURSDAY AND FRIDAY...BUT PROVIDE FOR WIDESPREAD 30S FRIDAY MORNING...IF NOT INTO THE WEEKEND AS THE HIGH ACTUALLY SETTLES OVERHEAD AND PROVIDE THE BEST RADIATIONAL COOLING SCENARIO. BY THIS TIME...THE EDGE WILL BE TAKEN OFF AS THE AIRMASS WILL BE SIGNIFICANTLY MODIFIED. EVEN WITH SUCH COOL TEMPERATURES...WILL LEAVE FROST MENTION OUT OF THE FORECAST FOR THIS PACKAGE. WOULD LIKE TO NAIL DOWN THE TIMING OF ANY LEFTOVER LAKE EFFECT CLOUDS WHICH COULD DEFINITELY IMPEDE THE DEGREE OF COOLING THURSDAY NIGHT. EVEN INTO THE WEEKEND...WITH THE MODIFICATION OF THE AIRMASS...CONDITIONS BECOME MORE IFFY FOR FROST TO BE WIDESPREAD. GIVEN DEGREE OF TROUBLE THE MODELS HAVE HAD WITH THIS TRANSITION SO FAR...WOULD LIKE TO SEE A LITTLE MORE CONTINUITY BEFORE DELVING TOO DEEPLY INTO THE FROST POTENTIAL. CERTAINLY IS SOMETHING TO CONSIDER IN THE COMING DAYS THOUGH. WITH THIS HIGH PRESSURE AS THE DOMINANT WEATHER SYSTEM...DRY WEATHER WILL TAKE HOLD LATE THIS WEEK INTO THE WEEKEND...WITH LITTLE MORE THAN LAKE EFFECT SHOWERS...WHICH WILL HOLD ON THROUGH THURSDAY AND PERHAPS INTO THURSDAY NIGHT/EARLY FRIDAY IN ADVANCE OF THE CENTER OF HIGH PRESSURE. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION/UPDATE...BT SHORT TERM...SF LONG TERM....DG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 405 AM CDT MON OCT 3 2005 .SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT THE RUC MODEL CURRENTLY SHOWS AN 850 MB LIFTED INDEX FROM MINUS 3 TO MINUS 5 ACROSS OUR FORECAST AREA. 850 MB THETA E ADVECTION IS ALSO INDICATED BY THE RUC MODEL PUSHING ACROSS THE EASTERN SECTIONS OF OUR FORECAST AREA EARLY THIS MORNING. THE AIR MASS IS GENERALLY CAPPED BUT WILL MENTION ISOLATED THUNDER THROUGH 14Z WITH RADAR SHOWING A CONVECTIVE CELL JUST EAST OF MSP. THE COLD FRONT IS FORECAST TO BECOME STATIONARY FROM SOUTHWEST MINNESOTA TO WEST CENTRAL WISCONSIN THIS AFTERNOON AND TONIGHT. WITH A MARGINALLY UNSTABLE AIR MASS AND SOUTHERLY FLOW OVER RUNNING THIS BOUNDARY...EXPECT A CHANCE OF DEVELOPING CONVECTION. THE BEST CHANCE OF PRECIPITATION EXPECTED TO BE ELEVATED CONVECTION NORTH OF THE STATIONARY FRONT BUT SEVERE STORMS POSSIBLE WITH CONVERGENCE NEAR THE BOUNDARY. INCLUDED A CHANCE OF CONVECTION SOUTH OF THE FRONT SINCE THE GFS AND NAM MODELS INDICATED THAT A SHORT WAVE NOW OVER KANSAS WILL MOVE NORTHEAST AND BRUSH THE FAR SOUTHEAST SECTIONS OF OUR COUNTY WARNING AREA BY THIS EVENING. THE SURFACE BOUNDARY IS EXPECTED TO REMAIN NEARLY STATIONARY FROM SOUTHWEST MINNESOTA TO WEST CENTRAL WISCONSIN TUESDAY. PRECIPITABLE WATER IS FORECAST TO INCREASES ACROSS THIS BOUNDARY TUESDAY AND THE GFS MODEL SHOWS A SIGNIFICANT 500 MB VORTICITY MAXIMUM MOVING ACROSS SOUTHERN MINNESOTA TOWARD WEST CENTRAL WISCONSIN. HEAVY RAIN IS POSSIBLE TUESDAY INTO TUESDAY NIGHT WITH A LOW PRESSURE CENTER FORECAST TO RIDE ALONG THE SURFACE BOUNDARY. A LOW LEVEL THETA E AXIS IS FORECAST TO FOLLOW THIS LOW PRESSURE CENTER ACROSS THE AREA TUESDAY NIGHT. RAIN EXPECTED TO CONTINUE WEDNESDAY INTO WEDNESDAY NIGHT...MAINLY ACROSS THE NORTHERN PORTIONS OF OUR FORECAST AREA....AS THE UPPER LEVEL LOW TRAILING THE SURFACE SYSTEM MOVES ACROSS NORTHERN MINNESOTA. LONGER TERM...THURSDAY THROUGH MONDAY VERY DRY AIR FILTERS IN BEHIND EXITING STRONG SHORT WAVE THU WHICH WILL MEAN QUICK SHUT OFF TO PRECIP IN ADDITION TO RAPID ARRIVAL OF SFC HIGH. THIS WILL LEAD TO DRY...COOL AND MAINLY CLEAR WEATHER INTO SAT MORN WHEN VERY WEAK COLD FRONT APPROACHES FROM DAKOTAS. EXACT TIMING OF FROPA DIFFERS BY 12 HRS /GFSLR SHOWS SAT NIGHT AND DGEX SHOWS SUN/ BUT BOTH MODELS AGREE THAT FRONT WILL BE MOISTURE STARVED SO ONLY EXPECTING SCT CLDS TO ACCOMPANY IT. DRY WRLY TO NWRLY FLOW BEHIND FROPA SUN NIGHT INTO MON WITH SLOWLY MODERATING TEMPERATURES. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 350 AM CDT MON OCT 3 2005 .DISCUSSION...FORECAST FOCUS ON NEAR RECORD HIGHS TODAY AND TUESDAY AHEAD OF DEVELOPING STRONG LOW OVER FAR NW WI WEDNESDAY MORNING. PERSISTENT SW FLOW AHEAD OF DEEP TROF DIGGING INTO PAC NW WILL KEEP SUMMER-LIKE TEMPERATURES ACROSS SRN WI INTO EARLY WEDNESDAY. MIXING OUT 850 MB TEMPS AROUND 18C GIVES HI TEMPS APPROACHING RECORD LEVELS. BEST CHANCE TO SET RECORD IS TODAY AT MKE (84) AND MSN (85). LIMITING FACTOR AT MKE TODAY WOULD BE ONSET OF LAKE BREEZE. BAROCLINIC LEAF ON WATER VAPOR AND RUC ANALYSIS SHOW SHORTWAVE TROUGH AXIS IN VCNTY OF TX/OK PANHANDLE WILL MOVE TOWARD FORECAST AREA BY LATE THIS AFTERNOON AND EVENING. BUFKIT SNDGS SHOW CAP BETWEEN 850 AND 750 MB AT PEAK HEATING...BUT LIFT FROM DCVA MAY BE ENOUGH TO OVERCOME. WL ADD A CHC OF TSTMS TO WRN CWA FOR LATE AFTERNOON/EVE. ANOTHER SHOT AT A RECORD HI TEMP TUE AT MSN WHICH AGAIN IS 85 DEGREES. DO NOT SEE MKE GETTING CLOSE TO THE RECORD OF 88 BECAUSE OF LAKE BREEZE POTENTIAL. ANOTHER LIMITING FACTOR AT BOTH LOCATIONS WOULD BE SCT SHRA/TSTMS TUE AFTERNOON. FCST SNDGS SHOW NO CAP MID AFTERNOON...WITH CAPES IN THE 1500 TO 1800 J/KG RANGE AND LI'S OF -2 TO -4. POTENTIAL TRIGGER WOULD BE SHRT WV INTERACTION AS RIPPLES RIDE TWD WI ON SW FLOW. HAVE ADDED CHC TSTMS FOR TUE AFTERNOON. STAYING WITH CONSENSUS GFS TIMING OF TROF AND STRONG COLD FRONT THRU RGN WED...WHICH IS IN LINE WITH PREV FCST. LINGERING CLOUDS AND POST FNTL PCPN WED NGT WILL LIMIT FROST POTENTIAL. WITH WINDS EXPECTED TO DECOUPLE AS HI PRES BUILDS OVER STATE AND GRADIENT SLACKENS...FROST WILL BE POSSIBLE EARLY FRIDAY MORNING OVER SOUTH CENTRAL WISCONSIN...AND WITH SURFACE HIGH OVER THE AREA FRIDAY NIGHT AND SATURDAY...AGAIN ACROSS THE AREA EARLY SATURDAY MORNING...THOUGH LESS LIKELY ALONG THE LAKE COUNTIES AS LAKE WATER TEMPS/850 MB TEMP DIFFERENCE AND NE FLOW WILL BRING STRATUS INLAND AS WELL AS SLIGHTLY WARMER TEMPS THAN OVER SOUTH CENTRAL. && .MKX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ REM wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 1000 AM CDT MON OCT 3 2005 .DISCUSSION... .UPDATE... ONLY SUBTLE TEMP AND PCPN CONCERNS FOR MRNG UPDATE. HAVE ADDED ISOLD SHWRS/TSTMS ENTIRE FA THIS AFTN WITH KS SHRT WV APCHG. XPC PERSISTENCE WITH KS ELEVATED CONVECTION AS IT REACHES IA. IMPRESSIVE MSTR TRANSPORT ALG 305K ISENT SFC ABV INVERSION THIS MRNG BUT ONLY SLGT LIFT IN PLACE. DEEPER MSTR LACKING SOMEWHAT TOO SO ALTHOUGH H85 COMPUTED CAPE 200-600 J/KG SUPRESSING CIN STILL IN PLACE WHICH SHOULD LMT AREAL CVRG. AT FIRST GLANCE GOING TEMPS WOULD SEEM FINE WITH 14Z OBS IN LOWER TO MIDDLE 70S ALREADY. HWVR AFT A LOOK AT NAM...RUC AND GFS FCST SOUNDINGS IT APPRS A FEW DEG TRIM WOULD BE IN ORDER. EVEN WARMEST RUC WITH SLGT SUPER-ADIABATIC NR SFC LAPSE RATES JUST REACH GOING HIGHS. CLDS AND PCPN SHOULD INCR SOMEWHAT THIS AFTN SO FEEL OUR RAPID TEMP RISE SHOULD STALL BY THAT TIME KEEPING HIGHS IN CHECK. NO OTHER SGFNT CHGS TO FCST. .PREV DISCUSSION... VRY WRM AMS IN PLACE WITH REC HI MID TEMPS ACRS STATE THIS MRNG. SHUD BE FAIRLY CLOSE TO REC HIGHS IN SVRL AREAS TDA WITH THE ONLY FLY IN THE OINTMENT BEING THE CLD COVER ASSOCD WITH S/WV LFGT OUT OF THE SRN RCKYS. CDFNT CONT TO SLOW DWN AS HAS BEEN TREND PAST SVRL DAYS. GFS SEEMS TO HV A GUD HNDL ON IT AND IS ABT IN LINE WITH CANADIAN ENS CHARTS. SEF RUN IS IN VRY CLOSE AGMT WITH GFS, GEM A BIT SLOWER BUT GEM ENS ABT THE SAME WITH TIMING AS GFS. ALL IN ALL FEEL GFS IS MDLS OF CHOICE WITH FNTL TIMING. IN THE LATER PDS, I.E. POST 84 HRS, THE GFS LKS TOO AGRESSIVE ON THE COLD AIR. A DECENT PUSH OF COLD AIR WILL OCCUR, BUT PROB NOT AS STG AS FCST. BELIEVE COLDER SOLNS SUGGEST A SNW CVR SOUTH OF 55 BY THU AND THUS THE -6 H8 AIR INTO NERN IA. DID HWVR SHAVE A FEW DEG ON THU MINS AND KEPT TEMPS AOB NORM AFT WED. WITH TIMING OF FNT, FEEL TUE NGT WL BE A WRM NGT, AND AS SUCH SHUD SEE FALLING TEMPS THRU WED AND HV WORDED THINGS THAT WAY. AS FOR PCPN, THE MAIN ACTION WL BE WITH THE CDFNT. SVRL EMBDD S/WVS IN THE SWLY FLOW DO POSE SOME LO RISK, BUT MAIN ACTION WL BE WITH CDFNT TUE AFTN AND TUE NGT. A FEW LINGERING SHRA POST FROPA, BUT DRY PUNCH SHOULD KEEP THE SHWRS AND SC DECK TO A MINIMUM. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SMALL ia AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1154 AM EDT MON OCT 3 2005 .UPDATE... EARLY MORNING CONVECTION THAT DEVELOPED AROUND SUNRISE ALONG THE MID-LEVEL MOIST AXIS HAS CLEARED EAST OF THE CWA. ONLY PATCHY MID/HIGH CLOUDS ARE LEFT ACROSS SOUTHERN LOWER...ALTHOUGH THETA-E RIDGE REMAINS IN PLACE WITH SOUTHEAST MICHIGAN WELL IN THE WARM SECTOR. WIDESPREAD DEWPOINTS IN THE MID 60S...WITH TEMPERATURES CLIMBING INTO THE LOW 80S. THIS WOULD LEAD TO NEARLY 1500J/KG MIXED LAYER CAPE OFF A MODIFIED 12Z DTX SOUNDING. HOWEVER GIVEN MID-LEVEL WARM ADVECTION...MODIFIED 12Z RUC SOUNDINGS ONLY SUPPORT TO 600J/KG MLCAPE. 15Z ACARS/TAMDAR SOUNDINGS SUPPORT THIS MID-LEVEL WARMING... INDICATING 700MB TEMPS ALREADY 1-2C WARMER. THIS WILL ALSO LEAD TO A MORE CAPPED ATMOSPHERE. WITH LITTLE SYNOPTIC SUPPORT...DO NOT EXPECT ANY REDEVELOPMENT DURING THE AFTERNOON. WILL UPDATE FORECAST TO REMOVE PRECIP AND ADJUST CLOUD WORDING...BUT REMAINDER OF THE FORECAST LOOKS ON TRACK. && .AVIATION...730 AM EDT MON OCT 3 2005 LIGHT MIST/FOG RATHER PREVALENT EARLY THIS MORNING AND HAVE MENTIONED AS MVFR IN AT LEAST TEMPO GROUP UNTIL 14Z...WITH EXPECTED INCREASING SUNSHINE/MIXING RAISING VISIBILITIES TO VFR BY THEN. WITH RADAR RECENTLY SHOWING MORE SCATTERED SHOWERS/THUNDER POPPING UP IN NORTHERN AREAS WHERE LEFT OVER OMEGA LIFT AND UPPER DIVERGENCE/LOW LEVEL CONVERGENCE ARE BEST...HAVE ALSO INCLUDED 3 MILES SHOWERS/MIST MENTION IN TEMPO GROUP AT KFNT AND KMBS...ALBEIT WITH VFR CEILINGS...BEFORE 14Z. THUNDER MAINLY EAST OF THESE TAF SITES. THEREAFTER TAFS REFLECT VFR CONDITIONS FOR THE BALANCE OF THE DAY AND EVEN MOST OF TONIGHT. WITH SKIES LARGELY CLEARING OVERNIGHT...THOUGH...WITH DECOUPLING WINDS AND HIGH SURFACE DEW POINTS IN PLACE...HAVE MENTIONED MVFR VISIBILITIES IN MIST/FOG BY 08Z. && .PREV DISCUSSION...ISSUED 428 AM EDT MON OCT 3 2005 SHORT TERM...TODAY AND TONIGHT MODEST SURFACE SOUTH TO SOUTHWEST FLOW OVER AREA THROUGH TONIGHT. WEAKENING 500 MB SHORTWAVE TROUGH OVERHEAD BY 12Z MOVES OFF TO THE EAST NORTHEAST THIS MORNING. WEAK 500 MB SHORTWAVE RIDGING BEHIND THIS TROUGH. PASSAGE OF SHORTWAVE TROUGH SHOULD END CHANCES OF SHOWERS/ISOLATED THUNDER BY SHORTLY AFTER NOON. WEAK 850 TO 500 MB QVECTOR CONVERGENCE CLIPPING NORTHERN COUNTIES TODAY ESPECIALLY THIS MORNING. ALSO GOOD 250 MB/850 MB DIVERGENCE/CONVERGENCE COUPLING THIS MORNING ESPECIALLY NORTH. IN ADDITION...MODEST 305K ISENTROPIC ASCENT AIDING PRECIPITATION CHANCES THIS MORNING. LINGERING LOW TO MID LEVEL OMEGA LIFT THIS MORNING TOO...BEST IN THE NORTH...GIVING WAY TO SUBSIDENCE THIS AFTERNOON. DEEPER MOISTURE LINGERING OVER AREA THIS MORNING...PEELING OFF TO THE EAST AND NORTHEAST THIS AFTERNOON. MODEST LOW TO MID LEVEL THETA E RIDGE OVERHEAD...ESPECIALLY NORTH...THIS MORNING AS WELL. MODEST INSTABILITY INDICES TODAY WITH RESPECTABLE LOW TO MID LEVEL LAPSE RATES AND K INDICES WELL INTO THE 30S...BUT MOISTURE/DYNAMICS FOR SUPPORTING RAINFALL WILL BE CONCENTRATED THIS MORNING. WILL ADD MENTION OF PATCHY FOG TONIGHT...AS WILL HAVE ENOUGH CLEARING TO PROMOTE RADIATIONAL COOLING AS HIGH DEW POINTS REMAIN IN PLACE. LONG TERM...TUESDAY THROUGH SUNDAY ON TUESDAY A SHEARED OUT FRONTAL BOUNDARY WILL BE LOCATED FROM NEWFOUNDLAND...ACROSS UPPER MICHIGAN...TO A DEEPENING LOW PRESSURE SYSTEM IN EASTERN COLORADO. SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG THIS BOUNDARY WITH ITS EXACT POSITION DEPENDING ON SHORTWAVES DROPPING SOUTHEAST ACROSS CENTRAL CANADA. THE MAJORITY OF THE MODELS...EXCLUDING THE 00Z/03 NAM...KEEP THIS BOUNDARY AND ASSOCIATED PRECIPITATION NORTH OF THE FORECAST AREA ON TUESDAY. WITH A STRONG TROUGH ADVANCING FROM THE WEST...FEEL THE NAM IS UNDER DONE WITH THE STRENGTH OF THE UPPER LEVEL RIDGE OVER THE GREAT LAKES REGION. WILL THEREFORE LEAN TOWARDS THE GFS SOLUTION WHICH INDICATES SURFACE THETA-E RIDGE WILL EXTEND NORTH TO LAKE MICHIGAN AND PARTIALLY INTO NORTHWEST LOWER TUESDAY AFTERNOON. WITH SOME MODEST INSTABILITY...CAPES AROUND 600 J/KG...THE TRI- CITIES AREA WILL HAVE A BETTER SHOT AT SEEING THUNDERSTORMS LATE TUESDAY AFTERNOON THAN THE REST OF THE CWA. WILL CONTINUE TO LEAVE FORECAST DRY HOWEVER...THINKING THAT THE UPPER LEVEL RIDGE WILL DOMINATE WITH A WEAK CAP IN PLACE AROUND 850MB AND MID-LEVEL LAPSE RATES OF ONLY 5.5 C/KM. UPPER LEVEL TROUGH OVER THE WESTERN UNITED STATES AND ASSOCIATED SURFACE LOW OVER EASTERN COLORADO WILL APPROACH THE WESTERN GREAT LAKES ON WEDNESDAY. GOOD MODEL AGREEMENT BETWEEN THE 00Z/03 GFS...ECMWF AND GEM ALL BRING A STRONG COLD FRONT THROUGH THE AREA AFTER MIDNIGHT WEDNESDAY NIGHT. POTENTIAL FOR THUNDERSTORMS AHEAD OF THE FRONT DOES NOT LOOK FAVORABLE AS RIDGING OVER THE GULF COAST STATES LIMITS MOISTURE TRANSPORT NORTH AHEAD OF THE FRONT. THE ATMOSPHERE WILL REMAIN CAPPED ON WEDNESDAY SO HAVE LOWERED CHANCE OF THUNDERSTORMS ACROSS THE AREA. GFS INDICATES ALMOST NO CAPE ALONG THE FRONT WITH A THUNDER-LESS LINE OF SHOWERS AND STRONG WINDS EXPECTED TO BE THE MAIN THREAT. HAVE ALSO RAISED TEMPS FOR WEDNESDAY/WEDNESDAY NIGHT GIVEN THE SLIGHTLY SLOWER FRONTAL TIMING. MODEL CONSENSUS STILL SHOWS 850MB TEMPS DROPPING TO -4C ON THURSDAY BEHIND THE FRONT. STRONG CAA WILL BRING SUSTAINED WINDS OF 15 TO 20 MPH WITH GUSTS AS STRONG AS 40 MPH DOWN TO THE SURFACE WEDNESDAY NIGHT AND THURSDAY MORNING. STEEP LOW LEVEL LAPSE RATES WILL KEEP SKIES MOSTLY CLOUDY ON THURSDAY WITH CHANCES OF PRECIPITATION ENDING BY LATE MORNING AS THE FRONT PULLS OUT OF OUR EASTERN COUNTIES. SKIES WILL CLEAR IN AREAS FURTHER AWAY FROM LAKE HURON THURSDAY NIGHT WITH TEMPS DROPPING DOWN INTO THE MID TO UPPER 30S. HAVE RAISED THESE TEMPS A COUPLE DEGREES FROM PREVIOUS FORECAST WITH MODELS SUGGESTING LIGHT WINDS PERSISTING THROUGH THE NIGHT AND SURFACE HIGH LOCATED NORTH OF LAKE SUPERIOR. WILL STILL NEED TO MONITOR POTENTIAL FOR FROST THURSDAY AND FRIDAY NIGHTS BUT NEITHER NIGHT PRESENTS IDEAL CONDITIONS FOR RADIATIONAL COOLING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE.......BRAVENDER AVIATION.....DWD SHORT TERM...DWD LONG TERM....KEK mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1143 AM EDT MON OCT 3 2005 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST UPDATE IS THE POTENTIAL FOR THUNDERSTORMS TODAY...AND THE HIGH TEMPERATURES. WATER VAPOR IMAGERY AND RUC/ETA SHOWING A BROAD RIDGE OVER QUEBEC AND DEEP LOW EMBEDDED IN A LONGWAVE TROUGH IS OFF THE BRITISH COLUMBIA. A WEAK SHORTWAVE WHICH TRAVERSED THE FORECAST AREA OVERNIGHT IS OVER EASTERN ONTARIO...FOLLOWED BY ANOTHER WEAKER SHORTWAVE OVER NORTHERN WISCONSIN. SCATTERED THUNDERSTORMS ARE FIRING OVER NORTHERN LOWER MICHIGAN IN ASSOCIATION WITH THE SHORTWAVE OVER EASTERN ONTARIO. SURFACE ANALYSIS INDICATE A LOW OVER HUDSON BAY AND A COLD FRONT DRAPES THROUGH ONTARIO...THE MINNESOTA ARROWHEAD...AND SOUTHERN MINNESOTA. THE SHORTWAVE OVER WISCONSIN WILL SHIFT INTO EAST CENTRAL ONTARIO. THE COLD FRONT MOVE SLOWLY ACROSS ONTARIO. HOWEVER...THE WEST END OF FRONT WILL REMAIN STATIONARY OVER NORTHERN MINNESOTA. THUS THE FRONT WILL STAY ALONG THE NORTHWEST SHORE OF LAKE SUPERIOR. LOW LEVEL CONVERGENCE OVER WESTERN LAKE SUPERIOR AHEAD OF THE FRONT WILL GENERATE CLOUDS AND POSSIBLY A THUNDERSTORM OR TWO. THUS WILL KEEP A MENTION OF SHOWERS AND THUNDERSTORMS OVER THE WEST THIS AFTERNOON. CLOUD COVER WITH HOLD DOWN THE TEMPERATURES A LITTLE ESPECIALLY OVER THE WEST. ON THE OTHER HAD...WARM AIR ADVECTION WITH A SOUTHWEST FLOW AHEAD OF THE FRONT WILL CAUSE THE TEMPERATURES TO RISE SO WILL STICK CLOSE TO GUIDANCE. DLG ONLY MINOR CHANGES FOR THE MORNING UPDATE TO THE LAKE SUPERIOR OPEN LAKE FORECAST AND NEARSHORE FORECASTS. HOWEVER...LATEST GUIDANCE RUNS NOW COMING IN LINE WITH LAST EVENINGS NAM FRONTAL POSITION...PLACING IT FURTHER TO THE SE ACROSS EASTERN LAKE SUPERIOR BY TUESDAY MORNING. AFTERNOON FORECAST PACKAGE WILL HAVE TO LOOK AT THIS POSSIBILITY MORE CLOSELY AS SIGNIFICANT CHANGES TO A N OR NE WIND DIRECTION ARE LIKELY IF THIS SCENARIO PANS OUT. IN ADDITION...THIS COOLER N TO NE FLOW WILL NO DOUBT DECREASE THE LOW LEVEL STABILITY RESULTING IN LIKELY CHANGES TO WAVE HEIGHT FORECASTS. AT THIS TIME WILL BE HESITANT TO MAKE SUCH AN ABRUPT CHANGE BASED ON A SINGLE GUIDANCE PACKAGE...BUT IF THE 12Z NUMBERS LOOK SIMILAR THEN A SIGNIFICANT CHANGE TO THE EAST HALF FORECAST AND NEARSHORE FORECAST TO THE NW OF MARQUETTE IS LIKELY WITH THE AFTERNOON PACKAGE. BAM && .MQT...WATCHES/WARNINGS/ADVISORIES...NONE. && $$ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 1032 AM CDT MON OCT 3 2005 .UPDATE...TODAY AND TONIGHT FRONTAL BNDRY EVIDENT IN 14Z MSAS ANALYSIS STRETCHING FM THE SWRN CORNER OF MN TO STC TO NR TAYLORS FALLS. LOOPS OF THE KMPX 0.5 DEG REFLECTIVITY SHOW A FINE LINE /PRESUMABLY A LOW TO MID LVL REFLECTION OF THE SFC FRONT/ PUSHING SLOWLY TO THE NW...AND AT 15Z WAS BISECTING STEARNS COUNTY. THIS REINFORCES THE EXPECTATION THAT THE SFC FRONT WILL MAKE SOME NWWRD PROGRESS BEFORE STALLING AGAIN ACRS THE NWRN QUARTER TO THIRD OF THE FA THIS AFTN AND EVE. VERY UNSEASONABLY MOIST LOW LEVELS CONT IN THE WARM SECTOR...WITH UPR 60S TO NR 70 DEG DEW POINTS EVIDENT IN THE 14Z SFC OBS ACRS MUCH OF SRN AND ERN MN AND W CNTRL WI. THESE CONDITIONS SHUD NOT CHG APPRECIABLY TDA...AS UPSTREAM OBS IN IA AND SRN WI SHOW SIMILAR CONDITIONS. 12Z KMPX RAOB SHOWS A FAIRLY MOIST LAYER BLO H7...WITH A MINOR DRY LAYER /DEW PT DEPRESSION OF 7C/ IN THE INVERSION LAYER NR 800MB...SO EVEN DAYTIME MIXING /ONCE THE CLOUDS LIGHTEN A BIT IN THE AFTN/ SHUD NOT CAUSE A LRG DROP IN SFC DEW PTS. WITH THE EXPECTATION OF HIGHS IN THE LOW TO MID 80S SE OF A RWF/CBG LN...PLENTY OF INSTABILITY WL BE IN PLACE FOR SOME TSRA THIS AFTN/EVE. S/W...EVIDENT IN W/V IMAGERY OVR FAR NERN KS ATTM...WILL CONT TO MOV NEWRD AND APPROACH THE FA TDA. THIS WL SERVE TO STRENGTHEN AND BACK THE LO LVL WIND FIELD...AND INCR CONVERGENCE IN THE FRONTAL AREA /MAINLY ACRS MY NRN COUNTIES/. RGNL PROFILER DATA ALREADY SHOW H8 WINDS IN THE 35 TO 40 KT RANGE /FM THE WSW/. AS THE S/W APPROACHES...THESE WINDS SHUD STRENGTHEN AND BACK TO A MORE S TO SW DIRECTION. GREATEST CHC OF TSRA SHUD BE INTO THE EVE/OVRNGT HRS WHEN THIS LLJ BEGINS TO INTERACT WITH THE FRONTAL BOUNDARY /MAINLY N OF A LN FM STC TO RCX/ DUE TO THE CAPPING INVERSION. WITH 40 TO 50 KTS OF 0-6 KM SHEAR PROGGED AND MID LEVEL LAPSE RATES NR 7C/KM...ANY CONVECTION THAT DOES DEVELOP HAS THE POTENTIAL TO PRODUCE SOME LRG HAIL DESPITE THE UNSEASONABLY HIGH FRZ LVL /14.1 KFT/ ON THE 12Z KMPX RAOB. UPDATED PRODUCTS HAVE BEEN SENT. && .PREV DISCUSSION... /ISSUED 405 AM CDT MON OCT 3 2005/ SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT THE RUC MODEL CURRENTLY SHOWS AN 850 MB LIFTED INDEX FROM MINUS 3 TO MINUS 5 ACROSS OUR FORECAST AREA. 850 MB THETA E ADVECTION IS ALSO INDICATED BY THE RUC MODEL PUSHING ACROSS THE EASTERN SECTIONS OF OUR FORECAST AREA EARLY THIS MORNING. THE AIR MASS IS GENERALLY CAPPED BUT WILL MENTION ISOLATED THUNDER THROUGH 14Z WITH RADAR SHOWING A CONVECTIVE CELL JUST EAST OF MSP. THE COLD FRONT IS FORECAST TO BECOME STATIONARY FROM SOUTHWEST MINNESOTA TO WEST CENTRAL WISCONSIN THIS AFTERNOON AND TONIGHT. WITH A MARGINALLY UNSTABLE AIR MASS AND SOUTHERLY FLOW OVER RUNNING THIS BOUNDARY...EXPECT A CHANCE OF DEVELOPING CONVECTION. THE BEST CHANCE OF PRECIPITATION EXPECTED TO BE ELEVATED CONVECTION NORTH OF THE STATIONARY FRONT BUT SEVERE STORMS POSSIBLE WITH CONVERGENCE NEAR THE BOUNDARY. INCLUDED A CHANCE OF CONVECTION SOUTH OF THE FRONT SINCE THE GFS AND NAM MODELS INDICATED THAT A SHORT WAVE NOW OVER KANSAS WILL MOVE NORTHEAST AND BRUSH THE FAR SOUTHEAST SECTIONS OF OUR COUNTY WARNING AREA BY THIS EVENING. THE SURFACE BOUNDARY IS EXPECTED TO REMAIN NEARLY STATIONARY FROM SOUTHWEST MINNESOTA TO WEST CENTRAL WISCONSIN TUESDAY. PRECIPITABLE WATER IS FORECAST TO INCREASES ACROSS THIS BOUNDARY TUESDAY AND THE GFS MODEL SHOWS A SIGNIFICANT 500 MB VORTICITY MAXIMUM MOVING ACROSS SOUTHERN MINNESOTA TOWARD WEST CENTRAL WISCONSIN. HEAVY RAIN IS POSSIBLE TUESDAY INTO TUESDAY NIGHT WITH A LOW PRESSURE CENTER FORECAST TO RIDE ALONG THE SURFACE BOUNDARY. A LOW LEVEL THETA E AXIS IS FORECAST TO FOLLOW THIS LOW PRESSURE CENTER ACROSS THE AREA TUESDAY NIGHT. RAIN EXPECTED TO CONTINUE WEDNESDAY INTO WEDNESDAY NIGHT...MAINLY ACROSS THE NORTHERN PORTIONS OF OUR FORECAST AREA....AS THE UPPER LEVEL LOW TRAILING THE SURFACE SYSTEM MOVES ACROSS NORTHERN MINNESOTA. LONGER TERM...THURSDAY THROUGH MONDAY VERY DRY AIR FILTERS IN BEHIND EXITING STRONG SHORT WAVE THU WHICH WILL MEAN QUICK SHUT OFF TO PRECIP IN ADDITION TO RAPID ARRIVAL OF SFC HIGH. THIS WILL LEAD TO DRY...COOL AND MAINLY CLEAR WEATHER INTO SAT MORN WHEN VERY WEAK COLD FRONT APPROACHES FROM DAKOTAS. EXACT TIMING OF FROPA DIFFERS BY 12 HRS /GFSLR SHOWS SAT NIGHT AND DGEX SHOWS SUN/ BUT BOTH MODELS AGREE THAT FRONT WILL BE MOISTURE STARVED SO ONLY EXPECTING SCT CLDS TO ACCOMPANY IT. DRY WRLY TO NWRLY FLOW BEHIND FROPA SUN NIGHT INTO MON WITH SLOWLY MODERATING TEMPERATURES. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...NONE. WI...NONE. && $$ KAT mn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 1025 AM CDT MON OCT 3 2005 .UPDATE...NO REAL UPDATE CONCERNS TODAY AS FORECAST IN GOOD SHAPE. COLD FRONT WHICH SWEPT THROUGH FORECAST AREA (FA) YESTERDAY HAS STALLED OUT JUST SOUTH OF A DLH-STC-SW MN LINE. 12Z RUC DEPICTS 850MB FRONT A BIT FURTHER NORTH THAN SFC FRONT...AND EXTREME SE FA MAY STILL SEE SHOWERS/THUNDER JUST NORTH OF THIS FRONT THIS AFTERNOON. TEMPERATURES ON TRACK ACCORDING TO RUC...WITH FILTERED SUN ALLOWING TEMPS TO REACH FORECASTED HIGHS. ONLY CHANGE WILL BE TO DECREASE MAX T 2F-3F ACROSS TOWNER/CAVALIER COUNTIES WITH THICKER CLOUDS PRESENT. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ TG nd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE NASHVILLE TN 1015 AM CDT MON OCT 3 2005 .DISCUSSION... SURFACE HIGH PRESSURE, CENTERED ALONG THE MID ATLANTIC COAST, WILL PRODUCE EAST TO SOUTHEAST FLOW ACROSS MIDDLE TENNESSEE THIS AFTERNOON. 12Z BNA SOUNDING SHOWED A NOTICEABLE INCREASE IN ATOMPSHERIC MOISTURE OVER THE LAST 24 HOURS IN THE 1000-700MB LAYER. IN ADDITION, THE MODIFIED SOUNDING FOR THIS AFTERNOON SHOWS AN ALMOST SUMMER-LIKE ENVIRONMENT, WITH AN LI OF -5, PWA OF 1.50 INCHES, TOTALS INDEX 48 AND A CAPE OF NEARLY 2000 J/KG. IN ADDITION, LATEST RUC SHOWS AN AREA OF PRECIPITATION FOR OUR FORECAST AREA TODAY, AND HAS ACTUALLY EXPANDED IT OVER THE ONE TARGETED BY THE 00Z GFS. THUS, WOULD NOT BE SURPRISED TO SEE SOME ISOLATED SHOWERS OR THUNDERSTORMS POP UP THIS AFTERNOON AND WILL INTRODUCE A 20% POP TO COVER THAT POSSIBILITY. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 19 tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 234 PM MDT MON OCT 3 2005 .SHORT TERM... (TONIGHT AND TUESDAY) A WEAK COLD FRONT SLIPPED INTO SOUTHEAST COLORADO THIS MORNING WITH A SHALLOW DOME OF COOL AIR APPARENTLY TOO SHALLOW FOR MODELS TO PICK UP ON. THIS DOME OF COOL AIR KEPT A SOUTHEAST COMPONENT ACROSS THE EASTERN PART OF THE REGION AND HELD TEMPERATURES DOWN AND THE GUSTY SOUTHWEST WINDS AT BAY. EXPECT THAT BOUNDARY TO WASH OUT AS THE NEXT SYSTEM APPROACHES. MOST AREAS WARMED PRETTY WELL ALTHOUGH A FEW DEGREES COOLER THAN EXPECTED IN THE ARKANSAS VALLEY. WINDS GUSTED OVER THE HIGHER TERRAIN WITH WEAK MOUNTAIN WAVE CLOUDS ALONG THE RIDGE OF THE SANGRE DE CRISTO MOUNTAINS. TONIGHT SHOULD BEHAVE SIMILAR TO LAST NIGHT WITH WINDS DECREASING AT THE LOWER ELEVATIONS BUT REMAINING GUSTY ACROSS THE HIGHER TERRAIN. SLOWER PROGRESSION OF THE NORTHWEST TROF SUGGESTED BY ALL MODELS WITH GFS THE SLOWEST. THIS PROMPTED ME TO REDUCE WINDS CLOSER TO THE RUC40/80 MODEL WHICH HAVE TENDED TO BE MORE CORRECT RECENTLY. NAM SEEMS TO OVER DO THE WIND SPEEDS. LIKEWISE THE SLOWER MOVEMENT KEEPS ANY MOISTURE AWAY FROM THE REGION SO ELIMINATED POPS MOST AREAS TONIGHT AND TUESDAY. WARMED OVERNIGHT LOWS A FEW DEGREES IN THE EAST MORE IN LINE WITH MET GUIDANCE FIGURING EVEN WITH RADIATIONAL COOLING THE ATMOSPHERE IS A COUPLE DEGREES WARMER THAN LAST NIGHT AND ADVECTION OF COOLER AIR IS BEING HELD OFF. STAYED WITH CURRENT FORECAST HIGHS ON TUESDAY. .LONG TERM... (TUESDAY NIGHT THROUGH MONDAY) 12Z AND 18Z RUNS OF THE NAM BRING THE FRONT IN A LITTLE FASTER THAN PREVIOUS RUNS...WHILE THE GFS IS STILL A LITTLE SLOWER THAN THE NAM. THE FRONT WL PUSH THRU THE SE PLAINS TUE NIGHT...AS THE UPR LOW MOVES INTO WRN SD. THERE WL BE SOME INCREASE IN LOW AND MID LVL MOISTURE...ALTHOUGH IT IS NOT REAL IMPRESSIVE. WL KEEP ISOLD TO SCT POPS ACRS THE AREA INTO LATE NIGHT...AND THEN IT DRIES OUT. BY WED AFTERNOON 700MB TEMPS RANGE FROM -1 TO +4 C ON THE GFS...WITH 0 TO -3 C ON THE NAM. THE TEMP DISCREPANCIES BETWEEN THE MODELS SHOW UP IN THE MOS WITH POOR AGREEMENT WITH REGARDS TO MAX TEMPS WED. CURRENT MAX T GRID MATCHES WILL WITH SURROUNDING AREAS SO WL MAKE FEW IS ANY CHANGES. MODELS SHOW A LITTLE LINGERING MSTR AROUND 700MB WED...BUT WL PROBABLY JUST BE SOME CLOUDS AND WL KEEP THE FORECAST DRY. AN UPR TROF MOVES OVR THE AREA THU. THERE WL ALSO BE A SLIGHT INCREASE IN MSTR THU...AND WL GO WITH SOME ISOLD POPS OVR FAR WRN AREAS...BUT FOR NOW WL KEEP THE REST OF THE AREAS DRY. TEMPS ALOFT WARM THU...BUT LOWER LEVEL TEMPS SHOW LITTLE WARMING...SO WL KEEP TEMPS COOL. AN UPR RIDGE BUILDS OVR THE AREA FOR FRI/FRI NIGHT ALLOWING FOR DRY WEA AND WARMER TEMPS. SAT THE RIDGE SHIFTS E AS AN UPR TROF MOVES ALONG THE W COAST. THE SW FLOW AHEAD OF THIS TROF... WL BRING AN INCREASE IN MSTR TO FAR WRN AREAS SO WL ADD SOME ISOLD POPS. THERE HAS BEEN A LOT OF UNCERTAINTY WITH THE WEEKEND WEA AS THE MODELS HAVE BEEN MAKING SOME DRASTIC CHANGES FROM RUN TO RUN. HOWEVER THE UKMO IS CURRENTLY LOOKING A LOT LIKE THE GFS. THE ECMWF ALSO SHOWS A TROF OVR THE WRN STATES. THE ECMWF MOVES THAT TROF ACRS CO SUN...WHILE THE GFS HOLDS IT BACK OVR UT/AX WITH THE LOW CLOSING OFF OVR AZ...GETTING WRAPPED UP AND STAYING OVR AZ THRU MON. THUS...THERE ARE STILL INCONSISTENCIES BETWEEN THE MODELS FOR SUN AND MON. FOR NOW WL MATCH SURROUNDING WFO/S WITH REGARDS TO PCPN AND TEMPS THESE DAYS. && .PUB WATCHES/WARNINGS/ADVISORIES...NONE. && $$ co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 132 PM EDT MON OCT 3 2005 .AVIATION... FOG POTENTIAL IS THE MAIN FOCUS FOR THIS TAF PERIOD. WIDESPREAD SURFACE DEWPOINTS IN THE 60S WILL PERSIST WITH SOUTHEAST MICHIGAN IN AN UNSEASONABLE WARM AIRMASS. SURFACE CONDENSATION PRESSURE DEFICITS ARE FORECAST TO DROP NEAR 10MB BY 12Z TUESDAY...SIMILAR TO ALTHOUGH A BIT DRIER THAN THOSE OBSERVED THIS MORNING. WHILE GRADIENT WEAKENS SOMEWHAT...A MODEST SOUTHERLY FLOW CONTINUES OVERNIGHT. FORECAST SOUNDINGS SHOW SOME POTENTIAL TO DECOUPLE WITH SURFACE BASED INVERSION DEVELOPING...ALTHOUGH DO NOT EXPECT THIS TO BE WIDESPREAD. WILL CARRY A MENTION OF MVFR FOG GENERALLY 08Z-15Z...AS WAS PREVALENT ACROSS THE LOWER GREAT LAKES/OHIO VALLEY THIS MORNING. OTHERWISE AFTER SCATTERED DIURNAL CU THIS AFTERNOON...ONLY MID/HIGH CLOUDS EXPECTED WITH WINDS BELOW 12KTS. && .UPDATE...1154 AM EDT MON OCT 3 2005 EARLY MORNING CONVECTION THAT DEVELOPED AROUND SUNRISE ALONG THE MID-LEVEL MOIST AXIS HAS CLEARED EAST OF THE CWA. ONLY PATCHY MID/HIGH CLOUDS ARE LEFT ACROSS SOUTHERN LOWER...ALTHOUGH THETA-E RIDGE REMAINS IN PLACE WITH SOUTHEAST MICHIGAN WELL IN THE WARM SECTOR. WIDESPREAD DEWPOINTS IN THE MID 60S...WITH TEMPERATURES CLIMBING INTO THE LOW 80S. THIS WOULD LEAD TO NEARLY 1500J/KG MIXED LAYER CAPE OFF A MODIFIED 12Z DTX SOUNDING. HOWEVER GIVEN MID-LEVEL WARM ADVECTION...MODIFIED 12Z RUC SOUNDINGS ONLY SUPPORT TO 600J/KG MLCAPE. 15Z ACARS/TAMDAR SOUNDINGS SUPPORT THIS MID-LEVEL WARMING... INDICATING 700MB TEMPS ALREADY 1-2C WARMER. THIS WILL ALSO LEAD TO A MORE CAPPED ATMOSPHERE. WITH LITTLE SYNOPTIC SUPPORT...DO NOT EXPECT ANY REDEVELOPMENT DURING THE AFTERNOON. WILL UPDATE FORECAST TO REMOVE PRECIP AND ADJUST CLOUD WORDING...BUT REMAINDER OF THE FORECAST LOOKS ON TRACK. && .PREV DISCUSSION...ISSUED 428 AM EDT MON OCT 3 2005 SHORT TERM...TODAY AND TONIGHT MODEST SURFACE SOUTH TO SOUTHWEST FLOW OVER AREA THROUGH TONIGHT. WEAKENING 500 MB SHORTWAVE TROUGH OVERHEAD BY 12Z MOVES OFF TO THE EAST NORTHEAST THIS MORNING. WEAK 500 MB SHORTWAVE RIDGING BEHIND THIS TROUGH. PASSAGE OF SHORTWAVE TROUGH SHOULD END CHANCES OF SHOWERS/ISOLATED THUNDER BY SHORTLY AFTER NOON. WEAK 850 TO 500 MB QVECTOR CONVERGENCE CLIPPING NORTHERN COUNTIES TODAY ESPECIALLY THIS MORNING. ALSO GOOD 250 MB/850 MB DIVERGENCE/CONVERGENCE COUPLING THIS MORNING ESPECIALLY NORTH. IN ADDITION...MODEST 305K ISENTROPIC ASCENT AIDING PRECIPITATION CHANCES THIS MORNING. LINGERING LOW TO MID LEVEL OMEGA LIFT THIS MORNING TOO...BEST IN THE NORTH...GIVING WAY TO SUBSIDENCE THIS AFTERNOON. DEEPER MOISTURE LINGERING OVER AREA THIS MORNING...PEELING OFF TO THE EAST AND NORTHEAST THIS AFTERNOON. MODEST LOW TO MID LEVEL THETA E RIDGE OVERHEAD...ESPECIALLY NORTH...THIS MORNING AS WELL. MODEST INSTABILITY INDICES TODAY WITH RESPECTABLE LOW TO MID LEVEL LAPSE RATES AND K INDICES WELL INTO THE 30S...BUT MOISTURE/DYNAMICS FOR SUPPORTING RAINFALL WILL BE CONCENTRATED THIS MORNING. WILL ADD MENTION OF PATCHY FOG TONIGHT...AS WILL HAVE ENOUGH CLEARING TO PROMOTE RADIATIONAL COOLING AS HIGH DEW POINTS REMAIN IN PLACE. LONG TERM...TUESDAY THROUGH SUNDAY ON TUESDAY A SHEARED OUT FRONTAL BOUNDARY WILL BE LOCATED FROM NEWFOUNDLAND...ACROSS UPPER MICHIGAN...TO A DEEPENING LOW PRESSURE SYSTEM IN EASTERN COLORADO. SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG THIS BOUNDARY WITH ITS EXACT POSITION DEPENDING ON SHORTWAVES DROPPING SOUTHEAST ACROSS CENTRAL CANADA. THE MAJORITY OF THE MODELS...EXCLUDING THE 00Z/03 NAM...KEEP THIS BOUNDARY AND ASSOCIATED PRECIPITATION NORTH OF THE FORECAST AREA ON TUESDAY. WITH A STRONG TROUGH ADVANCING FROM THE WEST...FEEL THE NAM IS UNDER DONE WITH THE STRENGTH OF THE UPPER LEVEL RIDGE OVER THE GREAT LAKES REGION. WILL THEREFORE LEAN TOWARDS THE GFS SOLUTION WHICH INDICATES SURFACE THETA-E RIDGE WILL EXTEND NORTH TO LAKE MICHIGAN AND PARTIALLY INTO NORTHWEST LOWER TUESDAY AFTERNOON. WITH SOME MODEST INSTABILITY...CAPES AROUND 600 J/KG...THE TRI- CITIES AREA WILL HAVE A BETTER SHOT AT SEEING THUNDERSTORMS LATE TUESDAY AFTERNOON THAN THE REST OF THE CWA. WILL CONTINUE TO LEAVE FORECAST DRY HOWEVER...THINKING THAT THE UPPER LEVEL RIDGE WILL DOMINATE WITH A WEAK CAP IN PLACE AROUND 850MB AND MID-LEVEL LAPSE RATES OF ONLY 5.5 C/KM. UPPER LEVEL TROUGH OVER THE WESTERN UNITED STATES AND ASSOCIATED SURFACE LOW OVER EASTERN COLORADO WILL APPROACH THE WESTERN GREAT LAKES ON WEDNESDAY. GOOD MODEL AGREEMENT BETWEEN THE 00Z/03 GFS...ECMWF AND GEM ALL BRING A STRONG COLD FRONT THROUGH THE AREA AFTER MIDNIGHT WEDNESDAY NIGHT. POTENTIAL FOR THUNDERSTORMS AHEAD OF THE FRONT DOES NOT LOOK FAVORABLE AS RIDGING OVER THE GULF COAST STATES LIMITS MOISTURE TRANSPORT NORTH AHEAD OF THE FRONT. THE ATMOSPHERE WILL REMAIN CAPPED ON WEDNESDAY SO HAVE LOWERED CHANCE OF THUNDERSTORMS ACROSS THE AREA. GFS INDICATES ALMOST NO CAPE ALONG THE FRONT WITH A THUNDER-LESS LINE OF SHOWERS AND STRONG WINDS EXPECTED TO BE THE MAIN THREAT. HAVE ALSO RAISED TEMPS FOR WEDNESDAY/WEDNESDAY NIGHT GIVEN THE SLIGHTLY SLOWER FRONTAL TIMING. MODEL CONSENSUS STILL SHOWS 850MB TEMPS DROPPING TO -4C ON THURSDAY BEHIND THE FRONT. STRONG CAA WILL BRING SUSTAINED WINDS OF 15 TO 20 MPH WITH GUSTS AS STRONG AS 40 MPH DOWN TO THE SURFACE WEDNESDAY NIGHT AND THURSDAY MORNING. STEEP LOW LEVEL LAPSE RATES WILL KEEP SKIES MOSTLY CLOUDY ON THURSDAY WITH CHANCES OF PRECIPITATION ENDING BY LATE MORNING AS THE FRONT PULLS OUT OF OUR EASTERN COUNTIES. SKIES WILL CLEAR IN AREAS FURTHER AWAY FROM LAKE HURON THURSDAY NIGHT WITH TEMPS DROPPING DOWN INTO THE MID TO UPPER 30S. HAVE RAISED THESE TEMPS A COUPLE DEGREES FROM PREVIOUS FORECAST WITH MODELS SUGGESTING LIGHT WINDS PERSISTING THROUGH THE NIGHT AND SURFACE HIGH LOCATED NORTH OF LAKE SUPERIOR. WILL STILL NEED TO MONITOR POTENTIAL FOR FROST THURSDAY AND FRIDAY NIGHTS BUT NEITHER NIGHT PRESENTS IDEAL CONDITIONS FOR RADIATIONAL COOLING. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION.....BRAVENDER UPDATE.......BRAVENDER SHORT TERM...DWD LONG TERM....KEK mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 1139 AM CDT MON OCT 3 2005 .UPDATE... MOISTURE RETURN HAS RESULTED IN SCATTERED /BROKEN LOW CLOUDS THIS MORNING ACROSS SOUTHEAST HALF OF FA. THIS SHOULD HELP KEEP TEMPS A LITTLE LOWER THAN YESTERDAY WITH EXCEPTION OF NORTHWEST PART OF STATE. WAVE AND LIGHT PRECIP HAVE MOVED INTO KANSAS SO WILL REMOVE POPS FROM NORTHWEST AREAS. GFS AND RUC STILL INDICATE SOME PRECIP POTENTIAL WITH MOISTURE RETURN THIS AFTERNOON BUT WITH WAVE MOVING OFF TO THE NORTH THINK THAT CLOUDS WILL BE MAIN STORY. STRONG COLD FRONT IS STILL EXPECTED TO ARRIVE WEDNESDAY WITH MUCH COOLER AIR. STILL SOME DETAILS TO WORK OUT WITH FRONTAL TIMING...BUT APPEARS GFS MAY HAVE BETTER HANDLE ON WESTERN TROUGH AND FRONTAL TIMING. WILL ISSUE SPECIAL WEATHER STATEMENT TODAY TO OUTLINE POTENTIAL IMPACTS WITH COLD FRONT. && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ SIX ok