AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SACRAMENTO CA 300 AM PDT THU OCT 5 2006 .DISCUSSION... UPPER LOW REMAINS PARKED JUST OFFSHORE OF THE BAY AREA. IT WILL PROBABLY BE HANGING AROUND THE REGION FOR THE REST OF THE WEEK. EXACTLY WHERE IT IS WILL HAVE A HUGE IMPACT ON OUR WEATHER. THE LAST FEW RUNS OF THE GFS AND THE WRF HAVE TRENDED TOWARD THE ECMWF...NOT MOVING THE LOW INTO CENTRAL CALIFORNIA UNTIL TONIGHT...AND DROPPING IT WELL SOUTH ALONG THE COAST AS IT DOES. THIS MAKES SOME SENSE GIVEN THE WARM SST ANOMALY / RIDGE DEVELOPING ALONG 140W. HOWEVER THE LATEST RUC AND CANSAC MM5 MOVE THE LOW INLAND THROUGH ABOUT 00Z BEFORE DROPPING IT SOUTH ALONG THE COAST TONIGHT. WILL TREND FORECAST TOWARD THIS SOLUTION AND A BRING A BAND OF SHOWERS INTO THE CENTRAL VALLEYS THIS MORNING. ISOLATED THUNDERSTORMS ARE ALSO POSSIBLE WITH A MODEST H5 -21C COLD POOL. WE'LL SEE A MIX OF SUN AND CLOUDS THIS AFTERNOON AS CONVECTIVE SHOWERS REMAIN POSSIBLE. IN THE MOUNTAINS EXPECT A BAND OF SHOWERS TO MOVE INTO THE WEST SLOPE OF THE SIERRA THIS MORNING PERHAPS AROUND 17Z. SNOW LEVELS WILL BE HIGHER THAN PREVIOUSLY THOUGHT AS THE MAIN COLD POOL MAY NEVER REALLY MOVE INLAND. HOWEVER...SNOW REMAINS POSSIBLE ABOVE 7000-7500 FEET AND A QUICK 1-2 INCHES IS STILL POSSIBLE OVER THE HIGHEST PASSES. AS THE ADVISORY HAS BEEN DROPPED WILL TRY TO COVER THIS IN THE ZFP...HWO AND NOWCASTS IF NECESSARY. SHOWER ACTIVITY ENDS TONIGHT AS THE LOW DROPS SOUTH AND NORCAL IS UNDER WEAK CYCLONIC FLOW. LOOKING AT THE MODELS THIS MORNING THE MOST LIKELY SCENARIO IS THAT THE LOW WILL SPLIT WITH A PORTION MOVING INTO THE GREAT BASIN WHILE ENERGY REMAINS OVER SOCAL INTO SATURDAY. EXPECT A LITTLE WARMER TEMPERATURES FRIDAY WITH INSTABILITY SHOWERS IN THE MOUNTAINS. SATURDAY SHOULD BE A PLEASANT DAY WITH A LOT OF SUN AS THE UPPER RIDGE NOSES INTO OREGON AND EXTREME NORCAL. SEVERAL MODELS DEPICT A DECENT NORTH WIND EVENT SATURDAY NIGHT AND SUNDAY. LATEST GFS KEEPS THIS UPPER LOW STATIONARY OVER SOCAL ALL THE WAY INTO THE WEEKEND. THIS WOULD KEEP IT TOO FAR SOUTH TO AFFECT US...EXCEPT FOR GUSTY NORTH WINDS. THE ECMWF DRIFTS IT NORTH ALONG THE COAST BY WEDNESDAY. WITH SO MUCH UNCERTAINTY WILL KEEP THE EXTENDED FORECAST DRY FOR NOW. SG && .AVIATION... VFR CONDITIONS WITH LOCAL MVFR CONDITIONS AND SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TODAY AS A CLOSED LOW MOVES DOWN THE CALIFORNIA COAST. ISOLD IFR CONDITIONS IN THE BAY AREA ESPECIALLY NEAR KSTS IN THE MORNING. SNOW LEVELS AROUND 7000 FEET. && .STO WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ca AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 855 PM EDT THU OCT 5 2006 .UPDATE... LATEST WATER VAPOR/RUC H5 COMPOSITE LOOP SHOWS CLOSED LOW EDGING SWD TOWARD THE CNTRL CA COAST. A DEEPENING SHORT WAVE TROUGH WAS PUSHING ACROSS THE GT LAKES AND MIDWEST. WEDGED IN BETWEEN IS A BUILDING RIDGE OVER THE PLAINS. THE SURFACE ANALYSIS DEPICTS WEAK HIGH PRESSURE OVER THE REGION...WITH A COLD FRONT EXTENDING FROM CNTRL LA THRU NCNTRL AL...ERN TN TO LOW PRESSURE OVER WRN NC. SKIES ARE M/CLEAR...WITH SOME MID/HIGH CLOUDS DRIFTING SEWD ACROSS CNTRL AL AND NRN GA. THE 00Z TAE SOUNDING IS SIMILAR TO THE PREVIOUS 24 HRS WRT PWAT (JUST BELOW AN INCH). ONLY NOTEWORTHY DIFFERENCES ARE SLIGHT WARMING IN THE MID LEVELS AND LIGHTER NELY WINDS IN THE LOW LEVELS. BASED ON OBS TREND...WILL UPDATE ZONES TO TWEAK WINDS. REMAINDER OF FIRST PERIOD ON TRACK. && .MARINE... BUOYS REPORTING NELY WINDS 10-15 KTS AND 2-3 FT SEAS. WINDS UPSTREAM AT MOB BUOY HAVE DECREASED BELOW 10 KTS...AND THIS TREND IS EXPECTED FOR OFFSHORE LEGS LATER TONIGHT. NEAR SHORE WINDS WERE NWLY AROUND 5 KTS...AND SHOULD BECOME LIGHT/VARIABLE LATER TONIGHT AS WELL. THEREFORE...NO CHANGES NECESSARY WITH THE EVENING FCST UPDATE. && .AVIATION... VFR CONDITIONS ON TAP OVERNIGHT...WITH ONLY LIGHT FOG EXPECTED. VSBYS MAINLY P6SM WITH ISOLATED 3-5SM BR IN SPOTS...KDHN WITH THE HIGHEST POTENTIAL FOR FOG. WIND WILL BE LIGHT & VARIABLE OVERNIGHT. COLD FRONT SAGS THROUGH THE AREA ON FRIDAY...SOME INCREASING CLOUDS...STILL VFR CONDITIONS...WITH ISOLATED SHOWERS & THUNDERSTORMS AHEAD OF IT. OVERALL CHANCE OF RAIN IS 20-30%...& USED VCTS WITH CB CLOUDS IN ALL TAFS AROUND 16Z-20Z. EXPECTING A SW WIND FLOW AROUND 5 MPH IN THE MORNING AHEAD OF THE FRONT...THEN BECOMING W-NW FLOW 5-10 MPH BEHIND THE FRONT. CLOUDS GRADUALLY CLEAR AFTER SUNSET FRIDAY. && .FIRE WEATHER... RED FLAG WARNING EXPIRED EARLY THIS EVENING...AND VERIFIED FOR MOST INLAND LOCALES. NO CONCERNS AT THIS TIME FOR FRIDAY...BUT GRIDS SUPPORT CRITICAL DURATIONS OF LOW RH OVER ALL OUR FLORIDA ZONES SATURDAY AND WE WILL ISSUE A FIRE WEATHER WATCH. && .TAE WATCHES/WARNINGS/ADVISORIES... AL...NONE. GA...NONE. FL...FIRE WEATHER WATCH ALL ZONES SATURDAY AFTN DUE TO EXPECTED LONG DURATIONS OF LOW RH. && $$ AVIATION...MCT REST OF DISCUSSION...MAJ fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 855 PM CDT THU OCT 5 2006 .DISCUSSION... EVENING SURFACE MAP SHOWS HIGH PRESSURE RIDGE STRETCHING FROM THE GREAT LAKES WESTWARD TOWARD THE CENTRAL PLAINS. UNDER CLEAR SKIES...TEMPS AROUND CENTRAL ILLINOIS HAVE GENERALLY DROPPED INTO THE LOWER TO MIDDLE 50S...WITH A FEW 40S ACROSS THE NW. IDEAL RADIATIONAL COOLING LIKELY WILL NOT BE ACHIEVED TONIGHT...AS RIDGE AXIS REMAINS JUST NW OF THE KILX CWA AND RESULTING PRESSURE GRADIENT KEEPS WINDS IN THE 5 TO 10 MPH RANGE. CURRENT ZONES HANDLE OVERNIGHT TRENDS WELL...WITH LOWS BOTTOMING OUT IN THE UPPER 30S AND LOWER 40S. WILL ONLY MAKE MINOR TWEAKS TO TEMPS...WITH THE BIGGEST CHANGE ACROSS THE SE CWA...WHERE TEMPS WILL BE LOWERED FROM THE MIDDLE 40S INTO THE LOWER 40S. && .PREV DISCUSSION... 18Z SURFACE ANALYSIS INDICATES A LOW DISSIPATING IN EASTERN KENTUCKY...WHILE A TRAINING TROUGH EXTENDS BACK TOWARD CENTRAL ILLINOIS. STEADY DRYING ALOFT HAS BEEN ABLE TO MIX DOWN AND THIN THE CLOUDS FROM NORTH TO SOUTH. RUC SOUNDINGS INDICATE A PINCH OF MOISTURE IN THE LOWER 100 MB WILL DISSIPATE BY 06Z. CU FROM DIURNAL HEATING HAVE REMAINED FARTHER NORTH IN WISCONSIN...AND THEY SHOULD DISSIPATE TOWARD SUNSET BEFORE AFFECTING US. MODELS IN DECENT AGREEMENT IN THE SHORT TERM ON TRENDS WITH THE HIGH PRESSURE. PROBLEMS ARISE IN THE LONG TERM... WITH THE DEEP LOW PRESSURE EXPECTED FOR MID WEEK NEXT WEEK. MAIN ISSUES ARE WITH THE TIMING OF THE CANADIAN FRONT FOR WED OR THUR. RIGHT NOW...ECMWF IS THE SLOWEST...WITH GFS AND CANADIAN QUICKER. WILL SIDE WITH RUC/NAM IN THE SHORT TERM... AND GFS/ECMWF BLEND IN LONG TERM. SHORT TERM...TODAY THROUGH SUNDAY... TEMPS ARE A MAIN CONCERN IN THE SHORT TERM WITH COOL HIGH PRESSURE SETTLING IN TONIGHT... AND REMAINING IN PLACE THROUGH SATURDAY MORNING. QUESTION IS HOW COLD TO GO...ESPECIALLY WITH THE SECOND NIGHT OF THE HIGH ON SATURDAY MORNING. WE ARE EXPECTED TO BE DIRECTLY UNDER THE RIDGE AXIS BY 12Z SAT AM. SOME RETURN FLOW IS POSSIBLE IN OUR NW ZONES...BUT EVERYWHERE ELSE WILL BE CALM. H85 TEMPS DO MODERATE SLIGHTLY BY SAT MORNING...BUT RADIATIONAL COOLING UNDER CLEAR AND CALM CONDITIONS CAN DROP LOWS LOWER THAN EXPECTED. FOR NOW...WILL KEEP LOWS IN THE UPPER 30S TO LOW 40S TONIGHT...WITH SIMILAR READINGS FOR SAT MORNING. EXCEPT ON SATURDAY MORNING...THE COLDEST AIR WILL BE IN THE EASTERN HALF OF THE CWA. BASICALLY GOING CLOSE TO GUID FOR LOWS TONIGHT...AND BELOW GUID FRI NIGHT. GRADUAL WARMING TREND AFTER SATURDAY MORNING...WITH H85 TEMPS REBOUNDING INTO THE 16-17C RANGE BY SUNDAY AFTERNOON. TEMP TRENDS WERE ALREADY HANDLED WELL IN THE GRIDS...WITH LITTLE CHANGES THERE. LONG TERM...MONDAY THROUGH THURSDAY... AN WEAK COLD FRONT IS EXPECTED FOR SUNDAY NIGHT AND MONDAY...BUT MOISTURE WILL BE VERY LIMITED AND SOURCES OF LIFT WILL BE WEAK. THE FRONT ACTUALLY WILL BE GOING THROUGH FRONTOLYSIS BY THE TIME IT REACHES US...AND LITTLE TO NO PRECIP IS EXPECTED. IF ANYTHING...MAYBE SOME POST FRONTAL SHOWERS IN THE CAA REGIME. THEN THE FOCUS TURNS TO THE LONG WAVE VORTEX THAT IS EXPECTED TO DROP SOUTH ON WEDNESDAY...WITH A COLD FRONT PASSING BY WED EVENING. MODELS USUALLY TREND SLOWER AS THE EVENT APPROACHES...BUT FOR NOW WILL INTRODUCE CHANCE POPS FOR WED NIGHT AND THURSDAY IN RESPONSE TO THE NEXT MAJOR H5 WAVE AND COLD PUSH. ENSEMBLE MEMBERS ARE NOT AS SHARP WITH THE TROUGH... BUT ANOMALOUS SOLUTIONS ARE NOT USUALLY FORECAST AS WELL IN THE LONG TERM. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ BARNES/SHIMON il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 136 PM CDT THU OCT 5 2006 .DISCUSSION... 18Z SURFACE ANALYSIS INDICATES A LOW DISSIPATING IN EASTERN KENTUCKY...WHILE A TRAINING TROUGH EXTENDS BACK TOWARD CENTRAL ILLINOIS. STEADY DRYING ALOFT HAS BEEN ABLE TO MIX DOWN AND THIN THE CLOUDS FROM NORTH TO SOUTH. RUC SOUNDINGS INDICATE A PINCH OF MOISTURE IN THE LOWER 100 MB WILL DISSIPATE BY 06Z. CU FROM DIURNAL HEATING HAVE REMAINED FARTHER NORTH IN WISCONSIN...AND THEY SHOULD DISSIPATE TOWARD SUNSET BEFORE AFFECTING US. MODELS IN DECENT AGREEMENT IN THE SHORT TERM ON TRENDS WITH THE HIGH PRESSURE. PROBLEMS ARISE IN THE LONG TERM... WITH THE DEEP LOW PRESSURE EXPECTED FOR MID WEEK NEXT WEEK. MAIN ISSUES ARE WITH THE TIMING OF THE CANADIAN FRONT FOR WED OR THUR. RIGHT NOW...ECMWF IS THE SLOWEST...WITH GFS AND CANADIAN QUICKER. WILL SIDE WITH RUC/NAM IN THE SHORT TERM... AND GFS/ECMWF BLEND IN LONG TERM. SHORT TERM...TODAY THROUGH SUNDAY... TEMPS ARE A MAIN CONCERN IN THE SHORT TERM WITH COOL HIGH PRESSURE SETTLING IN TONIGHT... AND REMAINING IN PLACE THROUGH SATURDAY MORNING. QUESTION IS HOW COLD TO GO...ESPECIALLY WITH THE SECOND NIGHT OF THE HIGH ON SATURDAY MORNING. WE ARE EXPECTED TO BE DIRECTLY UNDER THE RIDGE AXIS BY 12Z SAT AM. SOME RETURN FLOW IS POSSIBLE IN OUR NW ZONES...BUT EVERYWHERE ELSE WILL BE CALM. H85 TEMPS DO MODERATE SLIGHTLY BY SAT MORNING...BUT RADIATIONAL COOLING UNDER CLEAR AND CALM CONDITIONS CAN DROP LOWS LOWER THAN EXPECTED. FOR NOW...WILL KEEP LOWS IN THE UPPER 30S TO LOW 40S TONIGHT...WITH SIMILAR READINGS FOR SAT MORNING. EXCEPT ON SATURDAY MORNING...THE COLDEST AIR WILL BE IN THE EASTERN HALF OF THE CWA. BASICALLY GOING CLOSE TO GUID FOR LOWS TONIGHT...AND BELOW GUID FRI NIGHT. GRADUAL WARMING TREND AFTER SATURDAY MORNING...WITH H85 TEMPS REBOUNDING INTO THE 16-17C RANGE BY SUNDAY AFTERNOON. TEMP TRENDS WERE ALREADY HANDLED WELL IN THE GRIDS...WITH LITTLE CHANGES THERE. LONG TERM...MONDAY THROUGH THURSDAY... AN WEAK COLD FRONT IS EXPECTED FOR SUNDAY NIGHT AND MONDAY...BUT MOISTURE WILL BE VERY LIMITED AND SOURCES OF LIFT WILL BE WEAK. THE FRONT ACTUALLY WILL BE GOING THROUGH FRONTOLYSIS BY THE TIME IT REACHES US...AND LITTLE TO NO PRECIP IS EXPECTED. IF ANYTHING...MAYBE SOME POST FRONTAL SHOWERS IN THE CAA REGIME. THEN THE FOCUS TURNS TO THE LONG WAVE VORTEX THAT IS EXPECTED TO DROP SOUTH ON WEDNESDAY...WITH A COLD FRONT PASSING BY WED EVENING. MODELS USUALLY TREND SLOWER AS THE EVENT APPROACHES...BUT FOR NOW WILL INTRODUCE CHANCE POPS FOR WED NIGHT AND THURSDAY IN RESPONSE TO THE NEXT MAJOR H5 WAVE AND COLD PUSH. ENSEMBLE MEMBERS ARE NOT AS SHARP WITH THE TROUGH... BUT ANOMALOUS SOLUTIONS ARE NOT USUALLY FORECAST AS WELL IN THE LONG TERM. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...HUETTL LONG TERM....SHIMON il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LINCOLN IL 1045 AM CDT THU OCT 5 2006 .DISCUSSION... UPDATED THE FORECAST TO DELAY CLEARING SKIES ACROSS SE IL WHERE MOSTLY CLOUDY SKIES SHOULD PREVAIL TODAY. MUCH COOLER WITH HIGHS IN THE LOWER TO MIDDLE 60S. 15Z/10 AM SURFACE MAP SHOWS 1019 MB LOW PRESSURE JUST WEST OF LEXINGTON IN CENTRAL KY WITH THUNDERSTORMS NEAR THIS LOW. A COLD FRONT OVER SOUTHERN WV...CENTRAL KY AND WESTERN TN WHILE 1033 MB HIGH PRESSURE OVER NORTHERN WI TO EAST OF LAKE SUPERIOR AND RIDGING SW INTO THE CENTRAL PLAINS STATES. ALOFT A 592 DM 500 MB HIGH PRESSURE WAS OVER TX AND RIDGING NORTH ALONG THE FRONT RANGE OF THE ROCKIES WHILE A BROAD UPPER LEVEL TROF OVER THE GREAT LAKES WITH A SHORT WAVE IN KY. BROKEN TO OVERCAST STRATOCU CLOUDS BELOW 3000 FT WERE FROM THE IL RIVER SE WHILE CLEARING SKIES NW OF THE IL RIVER. LOWEST CEILING NEAR 1000 FT OVER SE IL. NE BREEZES 10 TO 20 MPH FILTERED IN MUCH COOLER AIR TODAY WITH LATE MORNING TEMPS IN THE MID TO UPPER 50S WITH AREAS FROM LITCHFIELD TO FLORA AND LAWRENCEVILLE AROUND 60F. USED RUC AND NAM/WRF 800 TO 900 MB LAYER 60 PERCENT RH FOR CLEARING WHICH MOVES FROM THE IL RIVER LATE THIS MORNING TO I-55 AROUND 18Z/EARLY AFTERNOON AND INTO SE IL...SE OF I-70 BY 00Z/SUNSET. CURULE DOES NOT SHOW MUCH CUMULUS CLOUDS REDEVLOPING OVER CENTRAL IL ONCE CLEARING MOVES IN. BEST DEVELOPMENT OF CUMULUS CLOUDS IVER OVER NE AND SOUTHERN IL AND INDIANA PER NAM/WRF CURULE THIS AFTERNOON. RUC AND NAM/WRF BOTH HAVE HIGHS IN THE LOW TO MID 60S AT 21Z WITH COOLEST READINGS NE AREAS. && .PREV DISCUSSION... FRONT MADE IT THROUGH THE REGION IN THE OVERNIGHT HOURS...WITH LITTLE FANFARE AND ONLY A FEW SHOWERS AND THUNDERSTORMS. LOW LEVEL CLOUDS LEFT IN THE WAKE...AND HIGH PRESSURE BEGINNING TO SLOWLY DRIFT SWD INTO THE REGION...WITH SOME MID LEVEL MOISTURE STILL SPILLING OVER THE UPPER LEVEL RIDGE ON WV SATELLITE IMAGERY. MAIN ISSUES FOR THIS FORECAST RUN WILL BE TEMPERATURES...AS THERE IS LITTLE ELSE TO DEAL WITH OTHER THAN HIGH PRESSURE AND THE PASSAGE OF AN INCREASINGLY DRY FRONT ON MONDAY. NO REASON TO STRAY FROM A BLEND OF THE MODELS THAT ARE COMING TOGETHER NICELY. SPREAD IN THE MOS IS A LITTLE MORE OF AN ISSUE...BUT WILL KEEP IN LINE WITH SOMEWHERE BETWEEN PERSISTENCE AND THE SLIGHTLY WARMER MAV MOS. SHORT TERM...TODAY THROUGH SATURDAY... FRONT IS GONE... NOW HOW FAST THE LOW CLOUDS GET OUT OF HERE IS THE NEXT ISSUE. GOING WITH A MORE OPTIMISTIC CLEARING AFTER NOON ACCORDING TO RH TIME HEIGHTS. MID LEVEL CLOUDS MAY LINGER A BIT...ENOUGH TO HOLD THE TEMPERATURES TO A RELATIVELY COOL MID 60S IN COMPARISON TO THE DAYS PRIOR. TONIGHT...CLEARED OUT SKIES AND RADIATIONAL COOLING WILL DROP THE TEMPS EFFECTIVELY...MAKING A TRUE WARM UP FOR FRIDAY A LITTLE MORE DIFFICULT. MOS DROPPING A BIT...AND HAVE FOLLOWED SUIT WITH THE FORECAST...BUT HESITATE TO DROP TOO LOW CONSIDERING 7-9C AT H85...PLENTY OF WARM AIR IN THE MID LEVELS ABOVE THAT...AND AMPLE SUNSHINE. FRIDAY...WINDS SHIFT TO SOUTHERLY AND HELP TO REALLY WARM UP...12-13C AT 850MB IN FORECAST SOUNDINGS...MID TO UPPER 70S YET AGAIN AHEAD OF THE NEXT FRONT. LONG TERM...SUNDAY THROUGH WEDNESDAY... WARMING TREND TO CONTINUE THROUGH SUNDAY...FRONTAL PASSAGE EXPECTED NOW SUNDAY NIGHT AND INTO MONDAY. HAVE BACKED OFF THE POPS IN THE FORECAST AS MODELS BEGINNING TO INDICATE A DRY PASSAGE. LACK OF SIGNIFICANT LAYER MOISTURE AND THE LOW EJECTING MORE TO THE NORTHEAST...WEAK LIFT IN THE BOUNDARY LAYER. LEAVING THE LOW SILENT 20S IN THERE AS A PLACE HOLDER IN THE CASE THAT THE SUBSEQUENT RUNS GIVE ANOTHER STORY...BUT UNLIKELY AT THIS POINT. AS FOR AFTER THE FRONT...FORECAST AGAIN ABOUT TEMPERATURES AS HIGH PRESSURE BUILDS BACK IN AT THE SFC. MID TO UPPER 60S BEHIND THE FRONT...AND CONTINUED DRY WEATHER. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ HUETTL/HJS il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 922 PM EDT THU OCT 5 2006 .EVENING UPDATE... MADE A FEW CHANGES TO THE FORECAST THIS EVENING. THE END OF THE LOW STRATUS IS BASICALLY ON THE NRN EDGE OF THE CWA ATTM. DISTANCE AND SPEED TOOLS INDICATE THAT CLEARING SHOULD TAKE PLACE ALONG THE OHIO RIVER AROUND 05Z...FROM BWG TO LEX AROUND 08Z...AND THE REST OF THE CWA BY 12Z. BUFKIT SOUNDINGS SUPPORT THIS...AS WELL AS NAM/GFS/RUC MODEL LOW-LEVEL RH FIELDS. THE 850MB RH HAS LINED UP REALLY WELL WITH THE STRATUS DECK...SO AM FOLLOWING THIS TO DETERMINE CLEARING TIME. THUS...WILL NOT KEEP CLOUDY WORDING OVERNIGHT AND WILL HAVE CLEARING WORDING...ESPECIALLY NW AFTER MIDNIGHT. HAVE TAKEN OUT DRIZZLE WORDING ACROSS THE NWRN TWO-THIRDS OF THE CWA...BUT WILL CONTINUE DRIZZLE EAST OF A FRANKFORT TO TOMPKINSVILLE LINE THROUGH MIDNIGHT EDT AS RUC 850-700MB OMEGA SHOWING LIFT. LOWER DEWPOINTS AND CONTINUED BREEZY NNE WINDS WILL LIKELY PRECLUDE FOG FROM FORMING. WILL ALSO CONTINUE HIGHER WIND WORDING IN THE ZONES OVERNIGHT. COULD SEE SOME GUSTS NEARING 20 MPH THROUGH NOON FRIDAY. HOURLY TEMPS WERE RUNNING A BIT COOLER IN THE SOUTH...SO DROPPED OVERNIGHT LOWS A DEGREE OR TWO IN SOUTHERN KY. ALSO LOWERED DEWPOINTS IN THIS REGION. UPDATE OUT MOMENTARILY. AL && .PREV DISCUSSION... SHORT TERM (TONIGHT THROUGH FRIDAY AFTERNOON)... WHAT A DIFFERENCE A DAY MAKES...SUNNY AND MID/UPPER 80S YESTERDAY... AND NOW TODAY MORE THAN HALF OF THE FORECAST AREA HAS WITNESSED FALLING TEMPS INTO THE UPPER 50S...AND DRIZZLE. HERE IS AN ODD LITTLE FACT...MANY HIGHS ACROSS THE REGION WERE AT MIDNIGHT...SO THE DAY WILL GO IN THE BOOKS AS NORMAL OR HIGHER MOST LIKELY AT ALL FOUR CLIMO SITES...THOUGH I BET MANY WOULD BEG TO DIFFER THERE. SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH A SFC WAVE HAS MOVED INTO EASTERN KY...ALLOWING FOR THE NORTHERLY WINDS TO DRAW IN COOLER AIR ACROSS THE LEXINGTON AREA AND SOUTH AS OF 3PM WITH TEMPS DROPPING AS MUCH AS 11 DEGREES IN THE LAST 2 HOURS.. SHRTWV MOVING ACROSS THE REGION HELPING TO PRODUCE THE LIFT AND DRIZZLE THAT HAS BEEN FOUND THROUGHOUT THE AFTERNOON ACROSS MOST OF THE WESTERN PORTIONS OF THE FORECAST AREA. LARGE DEWPOINT SPREAD AS WELL...WITH LOWER 60S REMAINING FROM LEX TO FTK...MUCH HIGHER TO THE SOUTH...AND DRIER AIR TO THE NORTH WITH LOW 50S ACROSS CENTRAL IN/SOUTHERN OHIO. STRONG INVERSION TRAPPING THE LOW LEVEL MOISTURE WITH CEILINGS NEAR 1K OR LESS ACROSS MUCH OF THE FORECAST AREA. HAVE LEANED HEAVILY ON THE RUC TO START THE FORECAST FOR THE PERIOD...CLOUDS LOOK TO HANG ON THRU MOST OF THE NIGHT...ESPECIALLY ACROSS THE SOUTH AND EASTERN PORTIONS OF THE AREA...BASICALLY EAST OF FRANKFORT TO BOWLING GREEN. WITH THE SHRTWV EXITING THE AREA LATE THIS EVENING...WILL KEEP DRIZZLE THROUGH THAT TIMEFRAME. EVEN WITH CAA ADVECTION TEMPS WILL DROP SLOWLY TONIGHT...COOLER IN THE HNB AREA WHERE SOME PARTIAL CLEARING MAY OCCUR LATE TONIGHT...WILL GO SLIGHTLY ABOVE MOS BLEND ELSEWHERE DUE TO THE CLOUDS. THE 925 RH REMAINS ABOVE 80 PERCENT ACROSS THE ENTIRE AREA THROUGH 06Z...I THINK THAT CLEARING AFTER THAT WOULD BE SLOWER THAN THE MODELS SHOW WITH NE FLOW FROM THE EASTERN GREAT LAKES...AND STRONG INVERSION TRAPPING THE MOISTURE. TYPICALLY WITH NE FLOW THE MOISTURE/CLOUDS REMAIN THROUGH THE NIGHT...WITH SOME MIXING POSSIBLE DURING THE FOLLOWING DAY THAT WILL LOWER THE COVERAGE OF THE STRATUS. WILL GO THIS WAY IN THE FORECAST...AND ERODE THE STRATUS DURING THE MORNING...SOME CU/SC WILL DEVELOP DURING THE DAY...MORE SO IN THE EAST TOWARDS THE HIGHER RH. TO HELP WITH THE TRANSPORT OF DRIER AIR WILL BE THE LARGE SFC HI THAT WILL MOVE FROM THE WESTERN GREAT LAKES TONIGHT...TO SE ONTARIO BY FRIDAY AFTERNOON. DEWPOINTS WILL FALL INTO THE LOWER 40S BY MID MORNING FRIDAY...WITH CONTINUOUS NE FLOW AT THE SFC...NORTHERLY FLOW ALOFT. HAVE LEANED TOWARDS THE LOWER END OF MOS GUIDANCE FOR TEMPS FRIDAY AFTERNOON...LOWER 60S IN THE BLUEGRASS REGION/ NE ZONES...TO MID TO UPPER 60S NEAR THE BWG AREA. SCHOTT LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)... QUITE A CHANGEABLE PATTERN OVER THE LONG TERM PERIOD. MODELS AGREE AS WEEKEND ARRIVES IN TAKING UPPER LEVEL TROUGH SOUTH ALONG THE ATLANTIC COAST. TO THE WEST...OVER THE LOWER OHIO AND TENNESSEE VALLEYS...UPPER LEVEL RIDGE ARCS NORTHEAST INTO THE EASTERN GREAT LAKES. WITH SURFACE FRONT CONTINUING SOUTHEAST...THIS SHOULD ALLOW FOR CLEAR SKIES OVER THE FORECAST AREA FRIDAY NIGHT THROUGH MUCH OF THE WEEKEND. A BROAD AND ELONGATED RIDGE OF HIGH PRESSURE FROM NEW ENGLAND SOUTHWEST TO THE MID MISSISSIPPI VALLEY AND BEYOND WILL BE RESPONSIBLE FOR THE CLEAR SKIES. TEMPERATURES THAT BEGIN QUITE COOL WILL MODERATE OVER THE WEEKEND. AFTER THE WEEKEND SHORTWAVES MOVING OUT OF THE NORTHEAST PACIFIC BEGIN BREAKING DOWN THE OHIO VALLEY RIDGE. NEXT COLD FRONT MOVES ACROSS THE REGION SUNDAY NIGHT...CREATING NOT MUCH MORE THAN CLOUDS. HIGH PRESSURE FOLLOWS...GIVING TWO MORE DRY DAYS...WITH TEMPERATURES COOLING A FEW DEGREES. A CLIPPER SYSTEM DROPPING SOUTHEAST OUT OF WESTERN CANADA WILL BRING THE NEXT CHANCE OF SHOWERS...ABOUT WEDNESDAY OF NEXT WEEK. THIS WILL BRING ANOTHER COLD FRONT AND SOMEWHAT COLDER TEMPERATURES FOR THE MIDDLE AND LATTER PARTS OF NEXT WEEK. IF THE GFS WITH ITS INCREDIBLY DEEP SYSTEM VERIFIES...WHICH AT THIS POINT WOULD BE VERY DOUBTFUL...HIGH TEMPERATURES COULD BE CHALLENGED TO GET MUCH INTO THE 50S. THE PROGRESS OF THIS WILL BE FOLLOWED CLOSELY FOR CONTINUITY OF NEXT RUNS OF THE COMPUTER MODELS. REITMEYER && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 315 PM EDT THU OCT 5 2006 .SHORT TERM (TONIGHT THROUGH FRIDAY AFTERNOON)... WHAT A DIFFERENCE A DAY MAKES...SUNNY AND MID/UPPER 80S YESTERDAY... AND NOW TODAY MORE THAN HALF OF THE FORECAST AREA HAS WITNESSED FALLING TEMPS INTO THE UPPER 50S...AND DRIZZLE. HERE IS AN ODD LITTLE FACT...MANY HIGHS ACROSS THE REGION WERE AT MIDNIGHT...SO THE DAY WILL GO IN THE BOOKS AS NORMAL OR HIGHER MOST LIKELY AT ALL FOUR CLIMO SITES...THOUGH I BET MANY WOULD BEG TO DIFFER THERE. SHOWER AND THUNDERSTORM ACTIVITY ASSOCIATED WITH A SFC WAVE HAS MOVED INTO EASTERN KY...ALLOWING FOR THE NORTHERLY WINDS TO DRAW IN COOLER AIR ACROSS THE LEXINGTON AREA AND SOUTH AS OF 3PM WITH TEMPS DROPPING AS MUCH AS 11 DEGREES IN THE LAST 2 HOURS.. SHRTWV MOVING ACROSS THE REGION HELPING TO PRODUCE THE LIFT AND DRIZZLE THAT HAS BEEN FOUND THROUGHOUT THE AFTERNOON ACROSS MOST OF THE WESTERN PORTIONS OF THE FORECAST AREA. LARGE DEWPOINT SPREAD AS WELL...WITH LOWER 60S REMAINING FROM LEX TO FTK...MUCH HIGHER TO THE SOUTH...AND DRIER AIR TO THE NORTH WITH LOW 50S ACROSS CENTRAL IN/SOUTHERN OHIO. STRONG INVERSION TRAPPING THE LOW LEVEL MOISTURE WITH CEILINGS NEAR 1K OR LESS ACROSS MUCH OF THE FORECAST AREA. HAVE LEANED HEAVILY ON THE RUC TO START THE FORECAST FOR THE PERIOD...CLOUDS LOOK TO HANG ON THRU MOST OF THE NIGHT...ESPECIALLY ACROSS THE SOUTH AND EASTERN PORTIONS OF THE AREA...BASICALLY EAST OF FRANKFORT TO BOWLING GREEN. WITH THE SHRTWV EXITING THE AREA LATE THIS EVENING...WILL KEEP DRIZZLE THROUGH THAT TIMEFRAME. EVEN WITH CAA ADVECTION TEMPS WILL DROP SLOWLY TONIGHT...COOLER IN THE HNB AREA WHERE SOME PARTIAL CLEARING MAY OCCUR LATE TONIGHT...WILL GO SLIGHTLY ABOVE MOS BLEND ELSEWHERE DUE TO THE CLOUDS. THE 925 RH REMAINS ABOVE 80 PERCENT ACROSS THE ENTIRE AREA THROUGH 06Z...I THINK THAT CLEARING AFTER THAT WOULD BE SLOWER THAN THE MODELS SHOW WITH NE FLOW FROM THE EASTERN GREAT LAKES...AND STRONG INVERSION TRAPPING THE MOISTURE. TYPICALLY WITH NE FLOW THE MOISTURE/CLOUDS REMAIN THROUGH THE NIGHT...WITH SOME MIXING POSSIBLE DURING THE FOLLOWING DAY THAT WILL LOWER THE COVERAGE OF THE STRATUS. WILL GO THIS WAY IN THE FORECAST...AND ERODE THE STRATUS DURING THE MORNING...SOME CU/SC WILL DEVELOP DURING THE DAY...MORE SO IN THE EAST TOWARDS THE HIGHER RH. TO HELP WITH THE TRANSPORT OF DRIER AIR WILL BE THE LARGE SFC HI THAT WILL MOVE FROM THE WESTERN GREAT LAKES TONIGHT...TO SE ONTARIO BY FRIDAY AFTERNOON. DEWPOINTS WILL FALL INTO THE LOWER 40S BY MID MORNING FRIDAY...WITH CONTINUOUS NE FLOW AT THE SFC...NORTHERLY FLOW ALOFT. HAVE LEANED TOWARDS THE LOWER END OF MOS GUIDANCE FOR TEMPS FRIDAY AFTERNOON...LOWER 60S IN THE BLUEGRASS REGION/ NE ZONES...TO MID TO UPPER 60S NEAR THE BWG AREA. .LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)... QUITE A CHANGEABLE PATTERN OVER THE LONG TERM PERIOD. MODELS AGREE AS WEEKEND ARRIVES IN TAKING UPPER LEVEL TROUGH SOUTH ALONG THE ATLANTIC COAST. TO THE WEST...OVER THE LOWER OHIO AND TENNESSEE VALLEYS...UPPER LEVEL RIDGE ARCS NORTHEAST INTO THE EASTERN GREAT LAKES. WITH SURFACE FRONT CONTINUING SOUTHEAST...THIS SHOULD ALLOW FOR CLEAR SKIES OVER THE FORECAST AREA FRIDAY NIGHT THROUGH MUCH OF THE WEEKEND. A BROAD AND ELONGATED RIDGE OF HIGH PRESSURE FROM NEW ENGLAND SOUTHWEST TO THE MID MISSISSIPPI VALLEY AND BEYOND WILL BE RESPONSIBLE FOR THE CLEAR SKIES. TEMPERATURES THAT BEGIN QUITE COOL WILL MODERATE OVER THE WEEKEND. AFTER THE WEEKEND SHORTWAVES MOVING OUT OF THE NORTHEAST PACIFIC BEGIN BREAKING DOWN THE OHIO VALLEY RIDGE. NEXT COLD FRONT MOVES ACROSS THE REGION SUNDAY NIGHT...CREATING NOT MUCH MORE THAN CLOUDS. HIGH PRESSURE FOLLOWS...GIVING TWO MORE DRY DAYS...WITH TEMPERATURES COOLING A FEW DEGREES. A CLIPPER SYSTEM DROPPING SOUTHEAST OUT OF WESTERN CANADA WILL BRING THE NEXT CHANCE OF SHOWERS...ABOUT WEDNESDAY OF NEXT WEEK. THIS WILL BRING ANOTHER COLD FRONT AND SOMEWHAT COLDER TEMPERATURES FOR THE MIDDLE AND LATTER PARTS OF NEXT WEEK. IF THE GFS WITH ITS INCREDIBLY DEEP SYSTEM VERIFIES...WHICH AT THIS POINT WOULD BE VERY DOUBTFUL...HIGH TEMPERATURES COULD BE CHALLENGED TO GET MUCH INTO THE 50S. THE PROGRESS OF THIS WILL BE FOLLOWED CLOSELY FOR CONTINUITY OF NEXT RUNS OF THE COMPUTER MODELS. -REITMEYER && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1120 AM EDT THU OCT 5 2006 .LATE MORNING UPDATE... WAVE CENTERED NEAR HODGENVILLE...WITH COLD FRONT STRETCHED SOUTHWEST TO FRANKLIN...AND WARM FRONT ALIGNED NEAR LEX TO THE EAST. ALL WILL CONTINUE TO DROP SLOWLY EAST SOUTH EAST...EXITING THE AREA AROUND 130 PM EDT/1230 CDT TO THE SOUTHEAST. SHOWERS AND THUNDERSTORMS WILL BE LIKELY RIGHT AHEAD AND ALONG THIS BOUNDARY THROUGH THAT TIME FRAME. WEAK SHRT WAVE MOVING THRU THIS AFTERNOON AHEAD OF THE MAIN UPPER LEVEL TROUGH MAY ALLOW FOR SOME LIGHT RAIN TO DEVELOP ACROSS THE AREA WITHIN THE STRATUS DECK. AS MENTIONED PREVIOUSLY...IFR CONDITIONS ARE PROBABLE THRU THE EARLY AFTERNOON...AND MAY LIFT SOME TO NEAR IFR CEILINGS 1K-1.5K FT THIS AFTERNOON. WINDS WILL ALSO BE MORE NOTICEABLE AS SFC WAVE MOVES EAST AND DECENT PRESSURE GRADIENT WILL EXIST ACROSS THE FORECAST AREA...10 TO 15 KT WOULD BE COMMON AS THE COOLER AIR WORKS INTO THE REGION FROM THE NORTH NORTHEAST. TEMPS CONTINUE TO FALL BEHIND THE FRONT...AND SHOULD SHOW NO UPWARDS MOVEMENT ONCE IT PASSES AND STRATUS MOVES IN. --SCHOTT MORNING UPDATE...ISSUED AT 815 AM EDT THU OCT 5 COLD FRONT STILL SLOWLY PUSHING THROUGH THE FORECAST AREA STRETCHING FROM NEAR LEXINGTON...SOUTHWEST ACROSS TO MORGANTOWN. A LINE OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS THE EASTERN PORTIONS OF THE FRONT IN THE CWA...SCTD ACTIVITY ACROSS THE WESTERN PORTIONS. A FEW STORMS ARE MODESTLY STRONG AND MAY CONTAIN SMALL HAIL...AND HEAVY DOWNPOURS. THUNDERSTORMS ACTIVITY LOOKS TO CEASE BY THE NOON HOUR ACROSS THE SOUTHEASTERN ZONES...MAINLY AROUND LAKE CUMBERLAND AND DALE HOLLOW LAKES...AS THE FRONT PUSHES SOUTH OUT OF THE AREA. ADDITIONAL SHOWERS LOOK POSSIBLE ACROSS THE AREA AS THE RUC STILL GENERATING QPF LATE IN THE AFTERNOON AS A UPPER LEVEL SHRTWV MOVES ACROSS THE REGION...WILL ADJUST TEMPS FOR CURRENT TRENDS...WITH THE RUC SHOWING FALLING TEMPS EVERYWHERE OUTSIDE OF THE SMALL AREA SOUTH OF THE FRONT...THEN DROPPING THERE AS WELL AFTER 18Z. CURRENT HOURLY GRIDS SHOW SOMETHING CLOSE TO THIS...SO JUST SOME MINOR CHANGES AS NEEDED. LOW STRATUS...WORKING INTO THE REGION FROM THE NORTH...CEILINGS NEAR OR LESS THAN 1000 FT...IFR CONDITIONS MAY BE LIKELY ACROSS MUCH OF THE AREA THIS MORNING BEFORE LIFTING SOME LATER THIS AFTERNOON. LINE OF STRATUS LIES APPROX FROM CYNTHIANA TO LOUISVILLE TO HAWESVILLE. SCHOTT DISCUSSION PREVIOUSLY ISSUED AT 305 AM EDT SHORT TERM (TODAY-TONIGHT)... SFC FRONT...AUGMENTED BY AN IMPRESSIVE OUTFLOW BOUNDARY SEEN ON RADAR...DROPPING SOUTHWARD TROUGH THE OHIO VALLEY ATTM. A WEAKENING SFC WAVE OF LOW PRESSURE ALONG THE BOUNDARY NEAR SDF HAS BEEN AIDING CONVECTIVE DEVELOPMENT NE OF THE LMK CWA OVER THE PAST FEW HOURS... BUT TO THE WEST PCPN HAS BEEN MUCH MORE WIDELY SCATTERED IN NATURE. LATEST SREF GUIDANCE CONTINUES TO FOCUS BEST PCPN CHANCES THROUGH DAYBREAK FROM OUR BLUEGRASS COUNTIES NE INTO OH/WV AND THIS SEEMS REASONABLE BASED ON RECENT RADAR TRENDS. ELSEWHERE IN CWA...WITH FRONT IN THE VICINITY...FEEL IT PRUDENT TO MAINTAIN SOME LOW CHC POPS THROUGH 12Z. AS FRONT PASSES THROUGH...BAND OF BKN-OVC LOW CLOUDS WILL FOLLOW. THIS IS SEEN IN LATEST 11-3.9 IR SAT PIX AND 0Z NAM LOW LEVEL RH FIELDS. MOST CIGS UPSTREAM ARE MVFR...BUT A COUPLE OB SITES ARE NOW SHOWING IFR CIGS BELOW 1KFT...SO WE'LL HAVE TO WATCH THAT. SREF IS INDICATING SOME SCT SHRA POSSIBLE WITHIN THIS POST-FRONTAL CLOUD COVER TODAY...LIKELY ASSOC WITH MODEST FRONTOGENESIS ALOFT BETWEEN 850-700MB. WILL CONTINUE CHC POPS FOR SHRA TODAY...HIGHEST IN THE E/SE SECTIONS OF THE CWA WHERE 850-800MB THETA-E RIDGE AXIS IS FCST. NAM IS INDICATING SOME NEGATIVE LI'S DEVELOPING BY MID AFTN OVER SE SECTIONS OF THE CWA...GIVEN THIS POSSIBILITY WILL MENTION THUNDER IN THESE ZONES. FOR TONIGHT...BKN-OVC LOW CLOUDS ARE EXPECTED TO BE WIDESPREAD AT THE BEGINNING OF THE PERIOD. INTO THE OVERNIGHT HOURS...NAM INDICATES THAT CLOUDS SHOULD BEGIN TO BREAK UP FROM N TO S UNDER A 20-30KT NE LOW LEVEL FLOW. LOCATIONS IN SRN KY MAY END UP REMAINING BKN-OVC MUCH OF THE NIGHT. WOULDN'T SURPRISE ME TO SEE SOME SPOTS OF DRIZZLE/SPRINKLES TONIGHT GIVEN FCST THICKNESS OF LOW CLOUDS. REGARDING TEMPS...TODAY WILL BE A CHALLENGE WITH THE FRONT IN THE AREA. IN THESE SITUATIONS I TYPICALLY FOLLOW THE RAW MODEL TEMPS RATHER THAN THE MOS GIVEN THE RAPIDLY CHANGING AIRMASS. SO WITH THIS REASONING...WE COULD SEE QUITE A TEMPERATURE GRADIENT TODAY FROM NW TO SE ACROSS THE CWA...FALLING TEMPS INTO THE LOW/MID 60S OVER THE SRN IND/LOU/LEX ZONES...WITH READINGS RISING WELL INTO THE 70S FOR BWG/SRN KY AHEAD OF THE FRONT. CONCEIVABLE THAT SOME OF OUR SE COUNTIES...IF ENOUGH SUNSHINE OCCURS...MAY REACH NEAR 80. FOR TONIGHT UNDER COLD ADVECTION...SHOULD SEE READINGS DROP INTO THE 40S IN MOST LOCATIONS. CS .LONG TERM (FRIDAY-WEDNESDAY)... 00 UTC MODELS CONT PREVIOUS SYNOPTIC TRENDS OF TRANSITIONING FM A RATHER ZONAL WNW FLOW REGIME IN SHORT TERM INTO A HIGHLY AMPLIFIED FLOW THIS WEEKEND AS SHORTWAVE DIGS SEWD AND FORMS LARGE CUT OFF LOW OVER/NEAR CAROLINAS. THIS BUILDS UPR RIDGE TO ITS WEST OVER MS VLY WHICH ALLOWS STG SFC HI PRES TO BUILD IN AND BECOME ANCHORED ACRS GRT LAKES AND OH VLY THIS WEEKEND. AS THIS OCCURS...TEMPS INITIALLY WILL BE RELATIVELY COOL FRI WITH HIGHS IN LOW TO MID 60S BUT WARM OVER THE WEEKEND INTO UPR 60S AND LWR 70S SAT...AND MID TO UPR 70S SUN. WITH GOOD RADIATIONAL COOLING SAT MRNG...LOWS SHOULD FALL TO AT OR BELOW GUIDANCE TEMPS TO AROUND/NEAR 40 MANY AREAS WITH UPR 30S PSBL IN COOLER VALLEYS. DRY WX WILL PREVAIL THRU WEEKEND. EARLY NEXT WEEK...SHORTWAVE ENERGY ACRS NRN TIER OF U.S. IS PROGGED TO SWEEP EWD AND FLATTEN UPR RIDGE. THIS SHOULD DRIVE A WEAK COLD FRONT ACRS GRT LAKES AND OH VLY LATE MON OR MON NGT. HWVR...FRONT SHOULD COME THRU DRY WITH LIMITED MOISTURE AND DYNAMICS. TEMPS WL BE COOLER THAN ON SUN...BUT NOT DRASTICALLY SO. LATEST GFS GEM AND ECMWF ARE HINTING AT A POTENTIAL SIGNIFICANT COOL DOWN OVER NRN TIER OF STATES AND GREAT LAKES INTO OH VLY BY MID TO LATE NEXT WEEK. OF COURSE...DETAILS OF THIS PATTERN ARE YET TO BE DETERMINED ALONG WITH TIMING OF WHEN COLDER AIR AND CHCS OF SHOWERS WOULD OCCUR. FOR NOW...LOOKS LIKE NEXT THU COULD BE TRANSITION DAY. MORE ON THIS AS TIME GROWS CLOSER. --TWF && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 815 AM EDT THU OCT 5 2006 .MORNING UPDATE... COLD FRONT STILL SLOWLY PUSHING THROUGH THE FORECAST AREA STRETCHING FROM NEAR LEXINGTON...SOUTHWEST ACROSS TO MORGANTOWN. A LINE OF SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS THE EASTERN PORTIONS OF THE FRONT IN THE CWA...SCTD ACTIVITY ACROSS THE WESTERN PORTIONS. A FEW STORMS ARE MODESTLY STRONG AND MAY CONTAIN SMALL HAIL...AND HEAVY DOWNPOURS. THUNDERSTORMS ACTIVITY LOOKS TO CEASE BY THE NOON HOUR ACROSS THE SOUTHEASTERN ZONES...MAINLY AROUND LAKE CUMBERLAND AND DALE HOLLOW LAKES...AS THE FRONT PUSHES SOUTH OUT OF THE AREA. ADDITIONAL SHOWERS LOOK POSSIBLE ACROSS THE AREA AS THE RUC STILL GENERATING QPF LATE IN THE AFTERNOON AS A UPPER LEVEL SHRTWV MOVES ACROSS THE REGION...WILL ADJUST TEMPS FOR CURRENT TRENDS...WITH THE RUC SHOWING FALLING TEMPS EVERYWHERE OUTSIDE OF THE SMALL AREA SOUTH OF THE FRONT...THEN DROPPING THERE AS WELL AFTER 18Z. CURRENT HOURLY GRIDS SHOW SOMETHING CLOSE TO THIS...SO JUST SOME MINOR CHANGES AS NEEDED. LOW STRATUS...WORKING INTO THE REGION FROM THE NORTH...CEILINGS NEAR OR LESS THAN 1000 FT...IFR CONDITIONS MAY BE LIKELY ACROSS MUCH OF THE AREA THIS MORNING BEFORE LIFTING SOME LATER THIS AFTERNOON. LINE OF STRATUS LIES APPROX FROM CYNTHIANA TO LOUISVILLE TO HAWESVILLE. SCHOTT DISCUSSION PREVIOUSLY ISSUED AT 305 AM EDT SHORT TERM (TODAY-TONIGHT)... SFC FRONT...AUGMENTED BY AN IMPRESSIVE OUTFLOW BOUNDARY SEEN ON RADAR...DROPPING SOUTHWARD TROUGH THE OHIO VALLEY ATTM. A WEAKENING SFC WAVE OF LOW PRESSURE ALONG THE BOUNDARY NEAR SDF HAS BEEN AIDING CONVECTIVE DEVELOPMENT NE OF THE LMK CWA OVER THE PAST FEW HOURS... BUT TO THE WEST PCPN HAS BEEN MUCH MORE WIDELY SCATTERED IN NATURE. LATEST SREF GUIDANCE CONTINUES TO FOCUS BEST PCPN CHANCES THROUGH DAYBREAK FROM OUR BLUEGRASS COUNTIES NE INTO OH/WV AND THIS SEEMS REASONABLE BASED ON RECENT RADAR TRENDS. ELSEWHERE IN CWA...WITH FRONT IN THE VICINITY...FEEL IT PRUDENT TO MAINTAIN SOME LOW CHC POPS THROUGH 12Z. AS FRONT PASSES THROUGH...BAND OF BKN-OVC LOW CLOUDS WILL FOLLOW. THIS IS SEEN IN LATEST 11-3.9 IR SAT PIX AND 0Z NAM LOW LEVEL RH FIELDS. MOST CIGS UPSTREAM ARE MVFR...BUT A COUPLE OB SITES ARE NOW SHOWING IFR CIGS BELOW 1KFT...SO WE'LL HAVE TO WATCH THAT. SREF IS INDICATING SOME SCT SHRA POSSIBLE WITHIN THIS POST-FRONTAL CLOUD COVER TODAY...LIKELY ASSOC WITH MODEST FRONTOGENESIS ALOFT BETWEEN 850-700MB. WILL CONTINUE CHC POPS FOR SHRA TODAY...HIGHEST IN THE E/SE SECTIONS OF THE CWA WHERE 850-800MB THETA-E RIDGE AXIS IS FCST. NAM IS INDICATING SOME NEGATIVE LI'S DEVELOPING BY MID AFTN OVER SE SECTIONS OF THE CWA...GIVEN THIS POSSIBILITY WILL MENTION THUNDER IN THESE ZONES. FOR TONIGHT...BKN-OVC LOW CLOUDS ARE EXPECTED TO BE WIDESPREAD AT THE BEGINNING OF THE PERIOD. INTO THE OVERNIGHT HOURS...NAM INDICATES THAT CLOUDS SHOULD BEGIN TO BREAK UP FROM N TO S UNDER A 20-30KT NE LOW LEVEL FLOW. LOCATIONS IN SRN KY MAY END UP REMAINING BKN-OVC MUCH OF THE NIGHT. WOULDN'T SURPRISE ME TO SEE SOME SPOTS OF DRIZZLE/SPRINKLES TONIGHT GIVEN FCST THICKNESS OF LOW CLOUDS. REGARDING TEMPS...TODAY WILL BE A CHALLENGE WITH THE FRONT IN THE AREA. IN THESE SITUATIONS I TYPICALLY FOLLOW THE RAW MODEL TEMPS RATHER THAN THE MOS GIVEN THE RAPIDLY CHANGING AIRMASS. SO WITH THIS REASONING...WE COULD SEE QUITE A TEMPERATURE GRADIENT TODAY FROM NW TO SE ACROSS THE CWA...FALLING TEMPS INTO THE LOW/MID 60S OVER THE SRN IND/LOU/LEX ZONES...WITH READINGS RISING WELL INTO THE 70S FOR BWG/SRN KY AHEAD OF THE FRONT. CONCEIVABLE THAT SOME OF OUR SE COUNTIES...IF ENOUGH SUNSHINE OCCURS...MAY REACH NEAR 80. FOR TONIGHT UNDER COLD ADVECTION...SHOULD SEE READINGS DROP INTO THE 40S IN MOST LOCATIONS. CS .LONG TERM (FRIDAY-WEDNESDAY)... 00 UTC MODELS CONT PREVIOUS SYNOPTIC TRENDS OF TRANSITIONING FM A RATHER ZONAL WNW FLOW REGIME IN SHORT TERM INTO A HIGHLY AMPLIFIED FLOW THIS WEEKEND AS SHORTWAVE DIGS SEWD AND FORMS LARGE CUT OFF LOW OVER/NEAR CAROLINAS. THIS BUILDS UPR RIDGE TO ITS WEST OVER MS VLY WHICH ALLOWS STG SFC HI PRES TO BUILD IN AND BECOME ANCHORED ACRS GRT LAKES AND OH VLY THIS WEEKEND. AS THIS OCCURS...TEMPS INITIALLY WILL BE RELATIVELY COOL FRI WITH HIGHS IN LOW TO MID 60S BUT WARM OVER THE WEEKEND INTO UPR 60S AND LWR 70S SAT...AND MID TO UPR 70S SUN. WITH GOOD RADIATIONAL COOLING SAT MRNG...LOWS SHOULD FALL TO AT OR BELOW GUIDANCE TEMPS TO AROUND/NEAR 40 MANY AREAS WITH UPR 30S PSBL IN COOLER VALLEYS. DRY WX WILL PREVAIL THRU WEEKEND. EARLY NEXT WEEK...SHORTWAVE ENERGY ACRS NRN TIER OF U.S. IS PROGGED TO SWEEP EWD AND FLATTEN UPR RIDGE. THIS SHOULD DRIVE A WEAK COLD FRONT ACRS GRT LAKES AND OH VLY LATE MON OR MON NGT. HWVR...FRONT SHOULD COME THRU DRY WITH LIMITED MOISTURE AND DYNAMICS. TEMPS WL BE COOLER THAN ON SUN...BUT NOT DRASTICALLY SO. LATEST GFS GEM AND ECMWF ARE HINTING AT A POTENTIAL SIGNIFICANT COOL DOWN OVER NRN TIER OF STATES AND GREAT LAKES INTO OH VLY BY MID TO LATE NEXT WEEK. OF COURSE...DETAILS OF THIS PATTERN ARE YET TO BE DETERMINED ALONG WITH TIMING OF WHEN COLDER AIR AND CHCS OF SHOWERS WOULD OCCUR. FOR NOW...LOOKS LIKE NEXT THU COULD BE TRANSITION DAY. MORE ON THIS AS TIME GROWS CLOSER. --TWF && .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 915 PM EDT THU OCT 5 2006 .UPDATE... TRANQUIL EVENING IS UNDERWAY ACROSS FCST AREA. SPRAWLING AREA OF SFC HIGH PRES IS CENTERED OVER NE LWR MI WITH UPPER MI STILL WITHIN THE BAGGY PRES GRADIENT NEAR HIGH CENTER. AS A RESULT...WINDS HAVE DROPPED OFF TO CALM THIS EVENING AS RADIATIONAL COOLING HAS SET UP SFC BASED INVERSION. LAND BREEZES ARE BEGINNING TO DEVELOP NEAR LAKE SUPERIOR. OVERNIGHT...THESE LAND BREEZES WILL BECOME INCREASINGLY AIDED BY THE INITIAL WEAK RETURN FLOW AROUND THE HIGH PRES CENTERED TO THE E. GOOD RADIATIONAL COOLING (CLEAR SKIES/CALM WIND) SHOULD CONTINUE THRU THE NIGHT AS ESTABLISHED SFC BASED INVERSION WILL LIMIT OR PREVENT MIXING TO THE SFC DESPITE SOME INCREASE IN RETURN FLOW ABOVE INVERSION AS HIGH DRIFTS E. HAVE ALREADY UPDATED FCST TO REFLECT THIS THINKING BY DROPPING LOWS TONIGHT A FEW DEGREES FROM PREV FCST IN MANY LOCATIONS. && .PREV DISCUSSION... SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RDG FROM THE SRN PLAINS TO SASK/MANITOBA WITH NW FLOW THROUGH WRN ONTARIO AND THE UPPER GRT LAKES. A SHRTWV MOVING THROUGH UPPER MI AND LK SUPERIOR HAS PRODUCED LITTLE MORE THAN ISOLD -SHRA/SPRINKLES OVER THE ERN CWA. OTHERWISE...CLEAR TO PARTLY CLOUDY SKIES PREVAILED FROM NE MN INTO W UPR MI. A SHRTWV OVER THE GULF OF AK WILL MOVE INTO BC AND EVENTUALLY THROUGH SRN CANADA HELPING TO STRENGTHEN AN SIGNIFICANT SFC LOW BY SAT/SUN FROM THE NRN PLAINS TO WRN ONTARIO. SHORT TERM...(TONIGHT AND FRI) TONIGHT...MID LVL AND SFC RDG BUILDING INTO THE UPPER GREAT LAKES WILL BRING MOSTLY CLEAR SKIES AND LIGHT WINDS. FAVORABLE RADIATIONAL COOLING CONDITIONS WILL ALLOW TEMPS TO DROP TO READINGS FROM AROUND 30 INLAND TO NEAR 40 ALONG THE LAKES. HOWEVER..THE SFC HIGH WILL SHIFT FAR ENOUGH TO THE EAST FOR SSW BNDRY LYR WINDS AOA 15 KT TO DEVELOP OVER THE W THIRD OF THE CWA...KEEPING TEMPS FROM FALLING OFF AS MUCH. FRI...INCREASING SRLY LOW LVL WINDS AND DECENT MIXING AOA 900 MB (TEMPS NEAR 9C) WITH PLENTIFUL SUNSHINE SHOULD SUPPORT TEMPS AOA GUIDANCE INTO THE LOWER TO MID 60S. LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)... WARMEST AIR AT H85 SURGES NORTHEAST INTO UPR MISSISSIPPI VALLEY AND FAR WESTERN FRINGES OF UPR GREAT LAKES FRI NIGHT. TIGHEST H85 BAROCLINIC ZONE SETS UP DAKOTAS INTO NORTHERN MN. ISENTROPIC LIFT NEAR 300K (850-750MB) A BIT MORE PRONOUNCED ON GFS THAN NAM BUT EVEN MAJORITY OF LIFT ON GFS IS OVR NORTHWEST LK SUPERIOR AND PERHAPS ACROSS KEWEENAW PENINSULA. TRIMMED POPS BACK OVR FAR WEST CWA. STRONG SOUTH WINDS WILL OVERTAKE UPR LAKES AND SET THE TONE FOR A BREEZY WEEKEND. NAM OUTPUT WAS FOLLOWED FOR WINDS FRI NIGHT AND SAT. BOTH PERIODS BLYR WINDS 30-35KT WERE PROGGED ON LK SUPERIOR AND IN DOWNSLOPING AREAS OF NCNTRL UPR MI. SETUP SEEMS GOOD FOR STRONG WINDS INTO SHORELINE AREAS OF BARAGA/MARQUETTE AND ALGER COUNTIES AS COOLER AIR OVR THE HIGHER TERRAIN DRAINS TOWARD LK SUPERIOR BUT IS COMPRESSIONALLY WARMED AS IT DECENDS. RESULT SHOULD BE AN INCREASE THE LOWER LEVEL LAPSE RATE AND ALLOWING FOR STRONGER MIXING. EXTENT OF MIXING/MAX TEMPS ARE MAIN QUESTIONS FOR SAT. BOTH NAM AND GFS SOUNDINGS INDICATE 925MB TO MAYBE 900MB FOR MIXING HEIGHT WHICH SUPPORTS MAX TEMPS INTO UPR 60S TO MID 70S. DEEP DRY LAYER EXPECTED WHICH MAY HELP MIX HIGHER. FOR NOW...LEFT MAX TEMPS WELL INTO THE 70S ALONE...AND WILL SEE HOW TEMPS UNFOLD FRI AFTN IN PLAINS. GOINT DEWPOINTS LOWERING WELL INTO THE 30S DURING THE AFTN LOOKS FINE BASED ON MIXING HEIGHTS. RESULTING RH VALUES FALL BLO 30 PCT. THUS...MAY HAVE SOME FIRE WEATHER CONCERNS ON SAT. AFTER COORD WITH MI DNR DID NOT GO WITH ANY HEADLINES RIGHT NOW. ON SUN...SOME WEAK 2D-FRONTOGENESIS AND POCKET OF MID LEVEL MOISTURE MAY COMBINE TO BRING A FEW SHOWERS...ESPECIALLY IN THE EAST HALF OF THE CWA IN AFTN. HOWEVER...IT IS SEEMING THAT MODELS ARE TRENDING TOWARD A DRY FRONTAL PASSAGE. EXPECT ANOTHER DAY OF WELL ABOVE NORMAL TEMPS. SIMILAR H9 TEMPS TO SAT MAY SUPPORT MORE MAX TEMPS INTO THE 60S AND POSSIBLY LWR 70S. AFTN DEWPOINTS SHOULD MIX INTO THE LWR-MID 40S YIELDING RH VALUES AROUND 30 PCT. THESE LOW RH VALUES AND RECENT DRY SPELL ALONG WITH A SHARP WIND SHIFT LATE DAY MAY LEAD TO FIRE WX CONCERNS AGAIN. WINDS WILL BECOME FOCUS BY LATE SUN AS WEST WINDS IN WAKE OF FRONT WILL BE STRONG INTO SUN NIGHT INTO MON. 12Z GFS A BIT QUICKER WITH WIND SHIFT THAN NAM BUT IN GENERAL BY 00Z MON BLYR WINDS INCREASE TO 35KT OVR LK SUPERIOR AND TO 20-30 KT OVR LAND SUN EVENING. KEWEENAW PENINSULA LOOKS IN LINE FOR AN ADVISORY EVENT WITH PREFERRED WEST WIND DIRECTION...WHILE A GALE IS PRETTY CERTAIN ON LK SUPERIOR. WILL MENTION BOTH IN HWOMQT. THESE STRONG WINDS WILL USHER IN COOL AIR TO UPR LAKES MON INTO MON NIGHT WITH H85 TEMPS FALLING SLIGHTLY BLO ZERO. PREVAILING WIND DIRECTION WILL BE NW SO ANY LK EFFECT WOULD OCCUR OVR E HALF OF LK SUPERIOR INTO FAR NE ZONES. INCREASED CLOUDS SOME IN THESE AREAS INTO MON NIGHT...BUT SOUNDINGS LOOK DRY ENOUGH TO PROHIBIT PCPN EVEN WITH FAVORABLE OVER WATER INSTABILITY (LAKE-H85 TEMP DIFFERENCES ARE ABOVE +13C). QUIET FOR TUE AS BRIEF RIDGING BUILDS OVR REGION. AT THE LEAST...WED-THU PERIODS AND LATER PERIODS LOOK MUCH COOLER AND UNSETTLED IN LATEST MEDIUM RANGE MODELS AND ASSOCIATED ENSEMBLES. RIDGE OVR CNTRL CONUS INTO EASTERN CANADA IS PROGGED TO GIVE WAY TO LARGE SCALE TROFFING FM CNTRL CANADA INTO GREAT LAKES. 00Z GFS/ECMWF/DGEX/CANADIAN INDICATE CENTER OF TROF SETTLING OVR ONTARIO WITH SFC LOW PASSING JUST NORTH OF LK SUPERIOR LATE WED INTO THU. THIS SOLN RESULTS IN WESTERLY WINDS GRADUALLY USHERING CHILLY AIRMASS INTO GREAT LAKES ON THU. 00Z/06Z/12Z GFS RUNS ARE CONSISTENTLY COLD WITH H85 TEMPS LOWERING BLO -10C INTO UPR MIDWEST AND GREAT LAKES BY 00Z FRI. 12Z ECMWF ALSO INDICATING SUB -10C H85 TEMPS INTO UPR LAKES LATE THU. SEEMS QUITE FEASIBLE NOW THAT LATER THU INTO FRI IF ENOUGH MOISTURE IS PRESENT WE MAY SEE FIRST SNOW OF THE SEASON FOR PORTIONS OF WESTERN UPR MI. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON (UPDATE) JLB (SYNOPSIS/SHORT TERM) JLA (LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 749 PM EDT THU OCT 5 2006 .AVIATION... WATER VAPOR IMAGERY REVEALS GOOD DRYING IN MID TO UPPER LEVELS PENETRATING SOUTHEAST MI BEHIND WELL DEFINED...BUT MOISTURE LIMITED...SHORTWAVE TROUGH SWINGING SOUTHEAST ACROSS THE AREA. ACCORDINGLY...MID AND HIGH CLOUDS HAVE SCOURED OUT OF ALL BUT THE SOUTHEASTERN COUNTIES...REVEALING A FAIRLY EXTENSIVE BUT OPEN STRATOCUMULUS FIELD. THESE STRATOCUMULUS...5K TO 6K FEET...APPEAR TO BE LARGELY DIURNALLY RELATED AND SHOULD DISSIPATE IN THE NEXT FEW HOURS. LOW THROUGH MID LEVEL QVECTOR AND OMEGA FIELDS INDICATE SUBSIDENCE THROUGH FRIDAY...AND AWIPS CUMULUS SCHEME IS VERY WEAK IN DIURNAL CLOUD DEVELOPMENT POTENTIAL FRIDAY. LATEST MODEL RUN TIME SECTIONS AND FORECAST MODEL SOUNDINGS FAIL TO GIVE MUCH POTENTIAL FOR LAKE EFFECT CLOUDS ADVECTING AND/OR DEVELOPING LATE TONIGHT INTO FRIDAY MORNING...ESPECIALLY NOT TO THE EXTENT THEY DID THURSDAY MORNING. STILL...MODELS SUCH AS RUC...NAM12 AND GFS DO HINT AT A BIT OF INCREASE IN 950 TO 925 MB MOISTURE IN NORTHEAST LOW LEVEL FLOW OFF OF LAKE HURON INTO MAINLY NORTHERN COUNTIES LATE TONIGHT INTO FRIDAY MORNING. TAFS REFLECT VFR CONDITIONS...EXCEPT FOR TEMPO GROUP FROM 10Z THROUGH 12Z AT KFNT FOR POSSIBLE CEILINGS NEAR 3K FEET. THERMAL TROUGH STILL HANGING AROUND OVERHEAD TONIGHT TO PROMOTE DELTA TS OVER LAKE HURON WELL INTO THE TEENS. && .PREV DISCUSSION...ISSUED 335 PM EDT THU OCT 5 2006 SHORT TERM...TONIGHT AND FRIDAY LAKE STRATUS COMBINING WITH THE APPROACH OF SHORT WAVE TROUGH AND THE PEAK HEATING HAS RESULTED IN SCT-BKN DECK NORTH OF M59 TODAY. IN FACT...SOME LIGHT RAIN SHOWERS HAVE BEEN OBSERVED VIA RADAR IN SAGINAW BAY INTO ADJACENT HURON AND TUSCOLA COUNTIES SHORELINES. SOME MESOSCALE INFLUENCES ARE OBSERVED IN THE 1KM IMAGERY AS A NORTHEAST COMPONENT TO THE WIND HAS KEPT SKIES MAINLY SUNNY SOUTH OF 8-MILE ROAD DOWN TO THE MICHIGAN STATE LINE. HERE TOO SOME CLOUDS WILL FILL IN AS THIS AFOREMENTIONED TROUGH SWINGS THROUGH THE REGION THIS EVENING. SKIES SHOULD CLEAR OUT THIS EVENING BUT THEN THE COMPLICATED LAKE STRATUS FORECAST DEVELOPMENT OVERNIGHT. ONCE AGAIN...THE WRF-NMM AND RUC2-13KM SUGGEST ANOTHER BAND OF LAKE CLOUDS WILL DEVELOP AND IMPACT BAX-JXN OVERNIGHT. HOWEVER...AS OBSERVED IN THE WATER VAPOR IMAGERY AND UPSTREAM SATELLITE TRENDS OFF LAKE SUPERIOR REVEAL CLOUDS DECREASING DUE TO THE INCREASED SUBSIDENCE. MODEL CONSENSUS FAVORS STRONG SUBSIDENCE OVERNIGHT AS TROUGH AMPLIFIES JUST TO OUR SOUTHEAST. SO AT THE MINIMUM CLR-PTCLOUDY SKIES FOR PORTIONS OF THE THUMB-FNT-OZW WITH MOCLEAR SKIES ELSEWHERE. WITH UPSTREAM DEWPOINTS INTO THE LOWER 30S AND DEWPOINTS ACROSS THE CWA INTO THE MIDDLE 30S...COMBINE THAT WITH SURFACE HIGH PRESSURE TO BUILD ACROSS THE STATE OVERNIGHT...TEMPERATURES SHOULD HAVE NO PROBLEM DIPPING DOWN INTO THE 30S AWAY FROM THE LAKE HURON SHORELINE...LAKE ERIE SHORELINE AND DOWNTOWN DTW (EVEN IF CLOUDS DEVELOP...SHOULD BE ENOUGH BREAKS). THEREFORE FROST ADVISORIES WILL BE HOISTED TONIGHT FOR MOST OF THE CWA. A NICE END TO THE WEEK WITH RIDGE BUILDING AT ALL LEVELS AND A DRY COLUMN TO BRING SUNSHINE. WITH MORE SUNSHINE AND A 2-3 DEGREE RISE AT 850MB...SHOULD RESULT INTO A NICE DIURNAL RISE OF 25-30 DEGREES INTO THE LOWER 60S INLAND...UPPER 50S NEAR LAKE HURON. LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY ANOTHER CHILLY/FROSTY START TO THE DAY IS IN STORE FOR SATURDAY AFTER A CLEAR FRIDAY NIGHT WITH CALM WIND AND CONTINUED IDEAL RADIATIONAL COOLING CONDITIONS. THE 12Z MODELS INDICATED SOME THIN CIRRUS IS POSSIBLE OVER THE AREA FRIDAY NIGHT WITH THE UPPER RIDGE AXIS JUST TO OUR WEST BUT NOT ENOUGH TO AID IN ELEVATING TEMPERATURES. THE GOING FORECAST CALLS FOR AREAS OF FROST IN MOST LOCATIONS AWAY FROM THE LAKES AND CITY OF DETROIT AND THIS LOOKS GOOD WITH LOW TEMPS AS CHILLY AS 32F POSSIBLE IN THE TYPICALLY COLDER LOCATIONS OF THE INTERIOR THUMB AND CENTRAL LOWER. THE WEEKEND WARMING TREND WILL THEN GET UNDERWAY DURING SATURDAY AFTERNOON. THE SURFACE RIDGE WILL SLIDE TO OUR EAST AND ALLOW SOUTHERLY RETURN FLOW TO BEGIN. MODEL FORECAST SOUNDINGS SHOW A MODEST MIXED BOUNDARY LAYER GENERALLY BELOW 900 MB. THIS IS ABOUT RIGHT FOR EARLY OCTOBER IN A STRONG LOW LEVEL WARM ADVECTION PATTERN. THE RESULT WILL BE HIGH TEMPS LOWER THAN THE POTENTIAL INDICATED BY WARMING 850 MB TEMPS BUT ON THE HIGH SIDE OF THE MACHINE NUMBERS WHEN FACTORING IN PLENTIFUL SUNSHINE. HIGHS WILL BE AT LEAST IN THE MID 60S AND WILL LIKELY TOUCH 70 IN THE SAGINAW VALLEY WITH STRONGER SW FLOW. THE SW FLOW WILL BE STRONGER BUT THE GRADIENT IN THE MODELS DOES NOT LOOK LIKE ENOUGH TO MAINTAIN A STEADY WIND SATURDAY NIGHT, ESPECIALLY SOUTH OF INTERSTATE 69. PLAN TO SHADE LOW TEMPS ON THE COOL SIDE OF GUIDANCE WITH THE EXPECTATION OF GREATER RADIATIONAL COOLING POTENTIAL. WITH ONLY THIN CIRRUS EXPECTED ONCE AGAIN, PREFER THE COOLER MET/NAM TEMPERATURE GUIDANCE WITH OFFERINGS DOWN NEAR 40. SUNDAY WILL BE VERY SIMILAR TO SATURDAY IN TERMS OF THE TEMPERATURE PROFILE AND SKY CONDITION, EXCEPT THE ENTIRE ATMOSPHERE WILL BE A FEW DEGREES WARMER THANKS TO EVEN STRONGER SW LOW LEVEL FLOW. THIS WILL BE DUE TO A RESPECTABLE LOW PRESSURE SYSTEM TAKING SHAPE IN CENTRAL CANADA, WHICH THE 12Z MODELS MAINTAIN ON THE STRONG SIDE AND CENTERED NEAR JAMES BAY BY SUNDAY AFTERNOON. HIGHS IN THE LOWER TO MID 70S WILL BE REACHABLE AHEAD OF THE ASSOCIATED COLD FRONT THAT WILL BE ON OUR DOORSTEP BY SUNDAY EVENING. TIMING ON THE PASSAGE OF THIS FRONT REMAINS CONSISTENT IN THE MODELS FOR SUNDAY NIGHT BUT WITH A LIMITED MOISTURE SUPPLY, SO MUCH SO THAT THE NORMALLY GENEROUS GFS OFFERS ONLY A FEW 100THS INCH QPF SUNDAY NIGHT AND MONDAY. MORE CERTAIN THAN RAIN CHANCES IS ANOTHER PUSH OF COLD AIR THAT WILL TAKE TEMPERATURES DOWN TO THE RANGE COMPARABLE TO EARLIER THIS WEEK WITH HIGHS IN THE UPPER 50S TO LOWER 60S AND THE USUAL COMPLEMENT OF COLD AIR STRATOCU ON MONDAY. CONSIDERING THE CONSISTENT TIMING ON THE SUNDAY NIGHT/MONDAY FRONTAL SYSTEM, CONFIDENCE IS MODERATE THAT HIGH PRESSURE WILL BE IN PLACE OVER SE MICHIGAN BY TUESDAY AS THE WHEELS TURN ON ANOTHER SUBSTANTIAL UPPER AIR PATTERN CHANGE. ADVERTISEMENT OF THIS BEGAN IN LAST NIGHTS MODEL RUNS AND CONTINUED TODAY. THE DRIVER OF THE CHANGE WILL BE STRONG AMPLIFICATION IN THE UPPER AIR PATTERN OVER THE EASTERN PACIFIC LEADING TO DOWNSTREAM DEVELOPMENT OF A LARGE CLOSED UPPER LOW DURING THE WEDNESDAY AND THURSDAY PERIOD. TRENDS IN THE 12Z RUN OF THE GFS SHOW AN UPPER AIR PATTERN THAT IS NOT AS DEEP/COLD AS THE PREVIOUS COUPLE OF RUNS, BUT WITH SIMILAR TIMING ON THE EVOLUTION OF THE SYSTEM. DETAILS ON THE SURFACE FEATURES WILL BE REFINED WITH TIME BUT THE BEST SHOT RIGHT NOW BRINGS THE COLD FRONT AND A CHANCE OF SHOWERS INTO THE AREA WEDNESDAY NIGHT AND THURSDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...FROST ADVISORY...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055- MIZ060-MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070-MIZ075- MIZ082...MIDNIGHT FRIDAY TO 9 AM FRIDAY. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION...DWD SHORT TERM...BGM LONG TERM....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 410 PM EDT THU OCT 5 2006 .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RDG FROM THE SRN PLAINS TO SASK/MANITOBA WITH NW FLOW THROUGH WRN ONTARIO AND THE UPPER GRT LAKES. A SHRTWV MOVING THROUGH UPPER MI AND LK SUPERIOR HAS PRODUCED LITTLE MORE THAN ISOLD -SHRA/SPRINKLES OVER THE ERN CWA. OTHERWISE...CLEAR TO PARTLY CLOUDY SKIES PREVAILED FROM NE MN INTO W UPR MI. A SHRTWV OVER THE GULF OF AK WILL MOVE INTO BC AND EVENTUALLY THROUGH SRN CANADA HELPING TO STRENGTHEN AN SIGNIFICANT SFC LOW BY SAT/SUN FROM THE NRN PLAINS TO WRN ONTARIO. && .SHORT TERM...(TONIGHT AND FRI) TONIGHT...MID LVL AND SFC RDG BUILDING INTO THE UPPER GREAT LAKES WILL BRING MOSTLY CLEAR SKIES AND LIGHT WINDS. FAVORABLE RADIATIONAL COOLING CONDITIONS WILL ALLOW TEMPS TO DROP TO READINGS FROM AROUND 30 INLAND TO NEAR 40 ALONG THE LAKES. HOWEVER..THE SFC HIGH WILL SHIFT FAR ENOUGH TO THE EAST FOR SSW BNDRY LYR WINDS AOA 15 KT TO DEVELOP OVER THE W THIRD OF THE CWA...KEEPING TEMPS FROM FALLING OFF AS MUCH. FRI...INCREASING SRLY LOW LVL WINDS AND DECENT MIXING AOA 900 MB (TEMPS NEAR 9C) WITH PLENTIFUL SUNSHINE SHOULD SUPPORT TEMPS AOA GUIDANCE INTO THE LOWER TO MID 60S. && .LONG TERM (FRIDAY NIGHT THROUGH THURSDAY)... WARMEST AIR AT H85 SURGES NORTHEAST INTO UPR MISSISSIPPI VALLEY AND FAR WESTERN FRINGES OF UPR GREAT LAKES FRI NIGHT. TIGHEST H85 BAROCLINIC ZONE SETS UP DAKOTAS INTO NORTHERN MN. ISENTROPIC LIFT NEAR 300K (850-750MB) A BIT MORE PRONOUNCED ON GFS THAN NAM BUT EVEN MAJORITY OF LIFT ON GFS IS OVR NORTHWEST LK SUPERIOR AND PERHAPS ACROSS KEWEENAW PENINSULA. TRIMMED POPS BACK OVR FAR WEST CWA. STRONG SOUTH WINDS WILL OVERTAKE UPR LAKES AND SET THE TONE FOR A BREEZY WEEKEND. NAM OUTPUT WAS FOLLOWED FOR WINDS FRI NIGHT AND SAT. BOTH PERIODS BLYR WINDS 30-35KT WERE PROGGED ON LK SUPERIOR AND IN DOWNSLOPING AREAS OF NCNTRL UPR MI. SETUP SEEMS GOOD FOR STRONG WINDS INTO SHORELINE AREAS OF BARAGA/MARQUETTE AND ALGER COUNTIES AS COOLER AIR OVR THE HIGHER TERRAIN DRAINS TOWARD LK SUPERIOR BUT IS COMPRESSIONALLY WARMED AS IT DECENDS. RESULT SHOULD BE AN INCREASE THE LOWER LEVEL LAPSE RATE AND ALLOWING FOR STRONGER MIXING. EXTENT OF MIXING/MAX TEMPS ARE MAIN QUESTIONS FOR SAT. BOTH NAM AND GFS SOUNDINGS INDICATE 925MB TO MAYBE 900MB FOR MIXING HEIGHT WHICH SUPPORTS MAX TEMPS INTO UPR 60S TO MID 70S. DEEP DRY LAYER EXPECTED WHICH MAY HELP MIX HIGHER. FOR NOW...LEFT MAX TEMPS WELL INTO THE 70S ALONE...AND WILL SEE HOW TEMPS UNFOLD FRI AFTN IN PLAINS. GOINT DEWPOINTS LOWERING WELL INTO THE 30S DURING THE AFTN LOOKS FINE BASED ON MIXING HEIGHTS. RESULTING RH VALUES FALL BLO 30 PCT. THUS...MAY HAVE SOME FIRE WEATHER CONCERNS ON SAT. AFTER COORD WITH MI DNR DID NOT GO WITH ANY HEADLINES RIGHT NOW. ON SUN...SOME WEAK 2D-FRONTOGENESIS AND POCKET OF MID LEVEL MOISTURE MAY COMBINE TO BRING A FEW SHOWERS...ESPECIALLY IN THE EAST HALF OF THE CWA IN AFTN. HOWEVER...IT IS SEEMING THAT MODELS ARE TRENDING TOWARD A DRY FRONTAL PASSAGE. EXPECT ANOTHER DAY OF WELL ABOVE NORMAL TEMPS. SIMILAR H9 TEMPS TO SAT MAY SUPPORT MORE MAX TEMPS INTO THE 60S AND POSSIBLY LWR 70S. AFTN DEWPOINTS SHOULD MIX INTO THE LWR-MID 40S YIELDING RH VALUES AROUND 30 PCT. THESE LOW RH VALUES AND RECENT DRY SPELL ALONG WITH A SHARP WIND SHIFT LATE DAY MAY LEAD TO FIRE WX CONCERNS AGAIN. WINDS WILL BECOME FOCUS BY LATE SUN AS WEST WINDS IN WAKE OF FRONT WILL BE STRONG INTO SUN NIGHT INTO MON. 12Z GFS A BIT QUICKER WITH WIND SHIFT THAN NAM BUT IN GENERAL BY 00Z MON BLYR WINDS INCREASE TO 35KT OVR LK SUPERIOR AND TO 20-30 KT OVR LAND SUN EVENING. KEWEENAW PENINSULA LOOKS IN LINE FOR AN ADVISORY EVENT WITH PREFERRED WEST WIND DIRECTION...WHILE A GALE IS PRETTY CERTAIN ON LK SUPERIOR. WILL MENTION BOTH IN HWOMQT. THESE STRONG WINDS WILL USHER IN COOL AIR TO UPR LAKES MON INTO MON NIGHT WITH H85 TEMPS FALLING SLIGHTLY BLO ZERO. PREVAILING WIND DIRECTION WILL BE NW SO ANY LK EFFECT WOULD OCCUR OVR E HALF OF LK SUPERIOR INTO FAR NE ZONES. INCREASED CLOUDS SOME IN THESE AREAS INTO MON NIGHT...BUT SOUNDINGS LOOK DRY ENOUGH TO PROHIBIT PCPN EVEN WITH FAVORABLE OVER WATER INSTABILITY (LAKE-H85 TEMP DIFFERENCES ARE ABOVE +13C). QUIET FOR TUE AS BRIEF RIDGING BUILDS OVR REGION. AT THE LEAST...WED-THU PERIODS AND LATER PERIODS LOOK MUCH COOLER AND UNSETTLED IN LATEST MEDIUM RANGE MODELS AND ASSOCIATED ENSEMBLES. RIDGE OVR CNTRL CONUS INTO EASTERN CANADA IS PROGGED TO GIVE WAY TO LARGE SCALE TROFFING FM CNTRL CANADA INTO GREAT LAKES. 00Z GFS/ECMWF/DGEX/CANADIAN INDICATE CENTER OF TROF SETTLING OVR ONTARIO WITH SFC LOW PASSING JUST NORTH OF LK SUPERIOR LATE WED INTO THU. THIS SOLN RESULTS IN WESTERLY WINDS GRADUALLY USHERING CHILLY AIRMASS INTO GREAT LAKES ON THU. 00Z/06Z/12Z GFS RUNS ARE CONSISTENTLY COLD WITH H85 TEMPS LOWERING BLO -10C INTO UPR MIDWEST AND GREAT LAKES BY 00Z FRI. 12Z ECMWF ALSO INDICATING SUB -10C H85 TEMPS INTO UPR LAKES LATE THU. SEEMS QUITE FEASIBLE NOW THAT LATER THU INTO FRI IF ENOUGH MOISTURE IS PRESENT WE MAY SEE FIRST SNOW OF THE SEASON FOR PORTIONS OF WESTERN UPR MI. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SYNOPSIS/SHORT TERM...JLB LONG TERM...JLA mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 335 PM EDT THU OCT 5 2006 .SHORT TERM...TONIGHT AND FRIDAY LAKE STRATUS COMBINING WITH THE APPROACH OF SHORT WAVE TROUGH AND THE PEAK HEATING HAS RESULTED IN SCT-BKN DECK NORTH OF M59 TODAY. IN FACT...SOME LIGHT RAIN SHOWERS HAVE BEEN OBSERVED VIA RADAR IN SAGINAW BAY INTO ADJACENT HURON AND TUSCOLA COUNTIES SHORELINES. SOME MESOSCALE INFLUENCES ARE OBSERVED IN THE 1KM IMAGERY AS A NORTHEAST COMPONENT TO THE WIND HAS KEPT SKIES MAINLY SUNNY SOUTH OF 8-MILE ROAD DOWN TO THE MICHIGAN STATE LINE. HERE TOO SOME CLOUDS WILL FILL IN AS THIS AFOREMENTIONED TROUGH SWINGS THROUGH THE REGION THIS EVENING. SKIES SHOULD CLEAR OUT THIS EVENING BUT THEN THE COMPLICATED LAKE STRATUS FORECAST DEVELOPMENT OVERNIGHT. ONCE AGAIN...THE WRF-NMM AND RUC2-13KM SUGGEST ANOTHER BAND OF LAKE CLOUDS WILL DEVELOP AND IMPACT BAX-JXN OVERNIGHT. HOWEVER...AS OBSERVED IN THE WATER VAPOR IMAGERY AND UPSTREAM SATELLITE TRENDS OFF LAKE SUPERIOR REVEAL CLOUDS DECREASING DUE TO THE INCREASED SUBSIDENCE. MODEL CONSENSUS FAVORS STRONG SUBSIDENCE OVERNIGHT AS TROUGH AMPLIFIES JUST TO OUR SOUTHEAST. SO AT THE MINIMUM CLR-PTCLOUDY SKIES FOR PORTIONS OF THE THUMB-FNT-OZW WITH MOCLEAR SKIES ELSEWHERE. WITH UPSTREAM DEWPOINTS INTO THE LOWER 30S AND DEWPOINTS ACROSS THE CWA INTO THE MIDDLE 30S...COMBINE THAT WITH SURFACE HIGH PRESSURE TO BUILD ACROSS THE STATE OVERNIGHT...TEMPERATURES SHOULD HAVE NO PROBLEM DIPPING DOWN INTO THE 30S AWAY FROM THE LAKE HURON SHORELINE...LAKE ERIE SHORELINE AND DOWNTOWN DTW (EVEN IF CLOUDS DEVELOP...SHOULD BE ENOUGH BREAKS). THEREFORE FROST ADVISORIES WILL BE HOISTED TONIGHT FOR MOST OF THE CWA. A NICE END TO THE WEEK WITH RIDGE BUILDING AT ALL LEVELS AND A DRY COLUMN TO BRING SUNSHINE. WITH MORE SUNSHINE AND A 2-3 DEGREE RISE AT 850MB...SHOULD RESULT INTO A NICE DIURNAL RISE OF 25-30 DEGREES INTO THE LOWER 60S INLAND...UPPER 50S NEAR LAKE HURON. && .LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY ANOTHER CHILLY/FROSTY START TO THE DAY IS IN STORE FOR SATURDAY AFTER A CLEAR FRIDAY NIGHT WITH CALM WIND AND CONTINUED IDEAL RADIATIONAL COOLING CONDITIONS. THE 12Z MODELS INDICATED SOME THIN CIRRUS IS POSSIBLE OVER THE AREA FRIDAY NIGHT WITH THE UPPER RIDGE AXIS JUST TO OUR WEST BUT NOT ENOUGH TO AID IN ELEVATING TEMPERATURES. THE GOING FORECAST CALLS FOR AREAS OF FROST IN MOST LOCATIONS AWAY FROM THE LAKES AND CITY OF DETROIT AND THIS LOOKS GOOD WITH LOW TEMPS AS CHILLY AS 32F POSSIBLE IN THE TYPICALLY COLDER LOCATIONS OF THE INTERIOR THUMB AND CENTRAL LOWER. THE WEEKEND WARMING TREND WILL THEN GET UNDERWAY DURING SATURDAY AFTERNOON. THE SURFACE RIDGE WILL SLIDE TO OUR EAST AND ALLOW SOUTHERLY RETURN FLOW TO BEGIN. MODEL FORECAST SOUNDINGS SHOW A MODEST MIXED BOUNDARY LAYER GENERALLY BELOW 900 MB. THIS IS ABOUT RIGHT FOR EARLY OCTOBER IN A STRONG LOW LEVEL WARM ADVECTION PATTERN. THE RESULT WILL BE HIGH TEMPS LOWER THAN THE POTENTIAL INDICATED BY WARMING 850 MB TEMPS BUT ON THE HIGH SIDE OF THE MACHINE NUMBERS WHEN FACTORING IN PLENTIFUL SUNSHINE. HIGHS WILL BE AT LEAST IN THE MID 60S AND WILL LIKELY TOUCH 70 IN THE SAGINAW VALLEY WITH STRONGER SW FLOW. THE SW FLOW WILL BE STRONGER BUT THE GRADIENT IN THE MODELS DOES NOT LOOK LIKE ENOUGH TO MAINTAIN A STEADY WIND SATURDAY NIGHT, ESPECIALLY SOUTH OF INTERSTATE 69. PLAN TO SHADE LOW TEMPS ON THE COOL SIDE OF GUIDANCE WITH THE EXPECTATION OF GREATER RADIATIONAL COOLING POTENTIAL. WITH ONLY THIN CIRRUS EXPECTED ONCE AGAIN, PREFER THE COOLER MET/NAM TEMPERATURE GUIDANCE WITH OFFERINGS DOWN NEAR 40. SUNDAY WILL BE VERY SIMILAR TO SATURDAY IN TERMS OF THE TEMPERATURE PROFILE AND SKY CONDITION, EXCEPT THE ENTIRE ATMOSPHERE WILL BE A FEW DEGREES WARMER THANKS TO EVEN STRONGER SW LOW LEVEL FLOW. THIS WILL BE DUE TO A RESPECTABLE LOW PRESSURE SYSTEM TAKING SHAPE IN CENTRAL CANADA, WHICH THE 12Z MODELS MAINTAIN ON THE STRONG SIDE AND CENTERED NEAR JAMES BAY BY SUNDAY AFTERNOON. HIGHS IN THE LOWER TO MID 70S WILL BE REACHABLE AHEAD OF THE ASSOCIATED COLD FRONT THAT WILL BE ON OUR DOORSTEP BY SUNDAY EVENING. TIMING ON THE PASSAGE OF THIS FRONT REMAINS CONSISTENT IN THE MODELS FOR SUNDAY NIGHT BUT WITH A LIMITED MOISTURE SUPPLY, SO MUCH SO THAT THE NORMALLY GENEROUS GFS OFFERS ONLY A FEW 100THS INCH QPF SUNDAY NIGHT AND MONDAY. MORE CERTAIN THAN RAIN CHANCES IS ANOTHER PUSH OF COLD AIR THAT WILL TAKE TEMPERATURES DOWN TO THE RANGE COMPARABLE TO EARLIER THIS WEEK WITH HIGHS IN THE UPPER 50S TO LOWER 60S AND THE USUAL COMPLEMENT OF COLD AIR STRATOCU ON MONDAY. CONSIDERING THE CONSISTENT TIMING ON THE SUNDAY NIGHT/MONDAY FRONTAL SYSTEM, CONFIDENCE IS MODERATE THAT HIGH PRESSURE WILL BE IN PLACE OVER SE MICHIGAN BY TUESDAY AS THE WHEELS TURN ON ANOTHER SUBSTANTIAL UPPER AIR PATTERN CHANGE. ADVERTISEMENT OF THIS BEGAN IN LAST NIGHTS MODEL RUNS AND CONTINUED TODAY. THE DRIVER OF THE CHANGE WILL BE STRONG AMPLIFICATION IN THE UPPER AIR PATTERN OVER THE EASTERN PACIFIC LEADING TO DOWNSTREAM DEVELOPMENT OF A LARGE CLOSED UPPER LOW DURING THE WEDNESDAY AND THURSDAY PERIOD. TRENDS IN THE 12Z RUN OF THE GFS SHOW AN UPPER AIR PATTERN THAT IS NOT AS DEEP/COLD AS THE PREVIOUS COUPLE OF RUNS, BUT WITH SIMILAR TIMING ON THE EVOLUTION OF THE SYSTEM. DETAILS ON THE SURFACE FEATURES WILL BE REFINED WITH TIME BUT THE BEST SHOT RIGHT NOW BRINGS THE COLD FRONT AND A CHANCE OF SHOWERS INTO THE AREA WEDNESDAY NIGHT AND THURSDAY. && .PREV DISCUSSION...ISSUED 101 PM EDT THU OCT 5 2006 AVIATION... COOL NORTHEAST FLOW OFF THE WARM WATERS OF LAKE HURON ALONG WITH THE APPROACH OF SHORT WAVE TROUGH ACROSS THE UPPER MISSISSIPPI RIVER VALLEY HAS RESULTED IN LAKE STRATUS...MAINLY VFR WITH BORDERLINE MVFR CEILINGS. AS THIS TROUGH AXIS TRANSLATES ACROSS THE REGION...EXPECT A LITTLE MORE CLOUD DEVELOPMENT THIS AFTERNOON. WITH THE PASSAGE OF THIS TROUGH...SUBSIDENCE TAKES PLACE WHICH SHOULD CLEAR SKIES OUT FOR AWHILE THIS EVENING. THE QUESTION OVERNIGHT WILL BE ADDITIONAL LAKE STRATUS DEVELOPMENT THAT WOULD IMPACT MAINLY FNT. LATEST WRF-NMM AND EXPERIMENTAL 2 RUC13 SUGGEST ONCE AGAIN THAT ANOTHER LAKE STRATUS DECK DEVELOPS OVERNIGHT AND EXTENDS FROM BAX-JXN. SINCE SUBSIDENCE SHOULD BE STRONGER BEHIND THIS WAVE...ONLY A TEMPO GROUP IS NEED AND MONITOR TRENDS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...FROST ADVISORY...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055- MIZ060-MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070-MIZ075- MIZ082...MIDNIGHT FRIDAY TO 9 AM FRIDAY. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...BGM LONG TERM....BT AVIATION...BGM YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 101 PM EDT THU OCT 5 2006 .AVIATION... COOL NORTHEAST FLOW OFF THE WARM WATERS OF LAKE HURON ALONG WITH THE APPROACH OF SHORT WAVE TROUGH ACROSS THE UPPER MISSISSIPPI RIVER VALLEY HAS RESULTED IN LAKE STRATUS...MAINLY VFR WITH BORDERLINE MVFR CEILINGS. AS THIS TROUGH AXIS TRANSLATES ACROSS THE REGION...EXPECT A LITTLE MORE CLOUD DEVELOPMENT THIS AFTERNOON. WITH THE PASSAGE OF THIS TROUGH...SUBSIDENCE TAKES PLACE WHICH SHOULD CLEAR SKIES OUT FOR AWHILE THIS EVENING. THE QUESTION OVERNIGHT WILL BE ADDITIONAL LAKE STRATUS DEVELOPMENT THAT WOULD IMPACT MAINLY FNT. LATEST WRF-NMM AND EXPERIMENTAL 2 RUC13 SUGGEST ONCE AGAIN THAT ANOTHER LAKE STRATUS DECK DEVELOPS OVERNIGHT AND EXTENDS FROM BAX-JXN. SINCE SUBSIDENCE SHOULD BE STRONGER BEHIND THIS WAVE...ONLY A TEMPO GROUP IS NEED AND MONITOR TRENDS. && .PREV DISCUSSION...ISSUED 1140 AM EDT THU OCT 5 2006 UPDATE... CURRENT FORECAST LOOKS ON-TRACK WITH LAKE STRATUS IMPACTING PORTIONS OF THE THUMB AND TRI CITIES AND HIGH LEVEL MOISTURE STRIPPING AWAY FROM THE GREAT LAKES REGION. SHORT WAVE WAS PROGRESSING NICELY ACROSS THE UPPER MISSISSIPPI RIVER VALLEY PER THE WATER VAPOR ANALYSIS. HOWEVER...ATMOSPHERE AHEAD OF THIS WAVE REMAINS QUITE DRY PER 12Z RAOBS FROM GRB/APX/DTX. THE ONLY EXCEPTION TO THIS WILL BE WHERE LAKE STRATUS IS PREVALENT AND WITH THE APPROACH OF THIS WAVE...MIGHT BE ENOUGH FOR A LIGHT RAIN SHOWER TO DEVELOP. SO THIS PART OF THE FORECAST REMAINS GOOD AT THIS TIME. TEMPERATURES BASED ON THE SOUNDINGS LOOK TO BE IN THE MIDDLE 50S FOR THE MOST PART...EXCEPTION WILL BE FURTHER SOUTH WERE A COUPLE OF LOW 60S ARE EXPECTED WITH MORE INSOLATION AND SLIGHTLY WARMER 850MB TEMPS. SHORT TERM...TODAY AND TONIGHT ALTHOUGH IT HAS BEEN SLOW TO OCCUR...THE FORMATION OF LAKE STRATUS SEEMS TO BE UNDERWAY IN COLD NORTHEAST FLOW. THUS...WILL RETAIN THE MENTION OF LIGHT SHOWERS OVER THE THUMB/SAGINAW VALLEY TODAY. EVEN TO THE SOUTH OF THIS...EXPECT DIURNAL CUMULUS/STRATO-CU TO DEVELOP AND LEAD TO PARTLY SUNNY SKIES. HIGH TEMPERATURES WILL HOLD IN THE MID TO UPPER 50S WHERE CLOUDS ARE MOST PREVALENT NORTH OF THE M 59 CORRIDOR OR SO. A BIT MORE SUNSHINE TO THE SOUTH OF THIS WILL LEAD TO LOWER 60S IN SOME SPOTS. WILL MAINTAIN THE MENTION OF FROST TONIGHT...BUT LEAVE ANY HEADLINE DECISIONS TO THE DAYSHIFT. REMAINING LAKE STRATUS...AND A SOMEWHAT STEADY FLOW OF HIGH LEVEL CIRRUS FROM THE WEST MAY IMPACT THE EXTENT OF FROST TO VARYING DEGREES...EVEN WITH HIGH PRESSURE BUILDING OVER THE AREA. BY THIS AFTERNOON...THE FULL EXTENT OF LAKE CLOUDS WILL BE EVIDENT. WIDESPREAD 30S ARE EXPECTED...WITH LOW HOLDING IN THE 40S ONLY NEAR THE RELATIVELY WARM LAKE WATERS AND PERHAPS THE CORE OF THE METRO DETROIT HEAT ISLAND. LONG TERM...FRIDAY THROUGH WEDNESDAY TOWARDS THE END OF THE WEEK...THE FLOW ACROSS THE CONUS BECOMES INCREASINGLY AMPLIFIED WITH A TROUGH OVER THE WEST COAST AND A BROAD RIDGE OVER THE EASTERN TWO THIRDS OF THE COUNTRY. A 1031MB SURFACE HIGH CENTERED OVER THE CENTRAL GREAT LAKES AND EXTENDING TO THE SOUTHERN MISSISSIPPI RIVER VALLEY WILL BUILD TOWARDS THE NEW ENGLAND STATES THROUGH SATURDAY. THE AIRMASS WILL BE VERY DRY OVER LOWER MICHIGAN WITH 1000-500MB RH OF 20-30%...KEEPING SKIES MOSTLY CLEAR THROUGH SUNDAY. AS THE HIGH BUILDS TO THE EAST...RETURN FLOW WILL INCREASE FROM THE SOUTH WITH TEMPERATURES GRADUALLY WARMING. GUIDANCE HIGHS APPEAR REASONABLE SHOWING THE WARMEST TEMPERATURES ON SUNDAY WITH A VERY PLEASANT WEEKEND IN STORE FOR LOWER MICHIGAN. THE NEXT SYSTEM TO APPROACH THE AREA WILL BE A RESULT OF ENERGY EJECTING OUT OF THE CLOSED LOW OVER THE WEST COAST...PHASING WITH A SHORTWAVE APPROACHING FROM THE GULF OF ALASKA. MODELS HAVE COME INTO MUCH BETTER AGREEMENT WITH THE STRENGTH OF THIS FEATURE OVER THE LAST 24 HOURS. LOW PRESSURE WILL DEVELOP OVER THE NORTHERN ROCKIES AND TRACK TOWARDS HUDSON BAY...WITH A TRAILING COLD FRONT AFFECTING LOWER MICHIGAN SUNDAY NIGHT. MOISTURE WILL BE LIMITED ALONG THE FRONT WITH HIGH PRESSURE OVER THE GULF STATES RESTRICTING MOISTURE TRANSPORT NORTH. SURFACE DEWPOINTS MAY STRUGGLE TO REACH THE LOW 50S AND SHOWALTERS ONLY DROP TO 5C. THE STRONGER FRONTAL FORCING WILL BE FOCUSED FROM CENTRAL WISCONSIN TO EXTREME NORTHERN LOWER...CLOSER TO THE MID LEVEL FRONTAL PUSH. WITH THE LACK OF MOISTURE AND INSTABILITY...HAVE DROPPED CHANCE OF THUNDERSTORMS FROM THE FORECAST LEAVING JUST A LOW CHANCE OF SHOWERS. THE COLD FRONT WILL DROP TEMPERATURES BACK DOWN INTO THE UPPER 50S THUMB TO LOW 60S ELSEWHERE THROUGH MID WEEK. MODELS ARE BEGINNING TO POINT TOWARDS A SIGNIFICANT COLD FRONT FOR LATE NEXT WEEK. IF MODELS VERIFY...A STRONG BLOCKING PATTERN IS FORECAST TO SET UP OVER THE GULF OF ALASKA WHICH WILL ALLOW A POLAR VORTEX AND THE COLDEST AIR OF THE SEASON TO TRACK FROM THE NORTHWEST TERRITORIES TO THE UPPER MIDWEST. THE GFS HAS BEEN LACKING CONSISTENCY AND THE 00Z/05 RUN SHOWS 500MB HEIGHTS BELOW THE RECORD LOW VALUES IN OUR 30 YEAR UPPER AIR CLIMATOLOGY DATABASE. TOO SOON TO HAVE MUCH CONFIDENCE IN THE EVOLUTION OF THIS PATTERN...BUT WILL KEEP AN EYE ON THE POTENTIAL FOR CONSIDERABLY BELOW NORMAL TEMPERATURES FOR THE END OF NEXT WEEK. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421-LHZ441 UNTIL 2 PM THURSDAY. SMALL CRAFT ADVISORY...LHZ422 UNTIL 1 PM THURSDAY. SMALL CRAFT ADVISORY...LHZ442-LHZ443 UNTIL 3 PM THURSDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY...LCZ423-LCZ460 UNTIL 1 PM THURSDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...LEZ444 UNTIL 1 PM THURSDAY. && $$ AVIATION.....BGM SHORT TERM...BGM LONG TERM....KAHL YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAS VEGAS NV 1015 AM PDT THU OCT 5 2006 .SYNOPSIS...AN AREA OF LOW PRESSURE WILL REMAIN NEARLY STATIONARY NEAR THE CENTRAL CALIFORNIA COAST TODAY. THE LOW WILL THEN SWING ACROSS THE SOUTHERN GREAT BASIN AND MOJAVE DESERT LATE TONIGHT AND FRIDAY. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED OVER SOUTHERN NEVADA AND NORTHWEST ARIZONA TODAY AND WILL BECOME MORE WIDESPREAD FRIDAY. TEMPERATURES WILL COOL TO BELOW NORMAL READINGS THROUGH SATURDAY. && .UPDATE...RECENT TRENDS FROM SATELLITE AND RADAR IMAGERY SHOWED THE NARROW BAND OF MOISTURE OVER SOUTHERN NEVADA EXPANDING AND SHIFTING SLIGHTLY WESTWARD. THE 12Z NAM INDICATES A WESTWARD SHIFT IN THE MOISTURE BOUNDARY WHICH THE 12Z GFS KEEPS IT FAIRLY STATIONARY. IN EITHER CASE...THE FORECAST NEEDED TO BE UPDATED ACROSS SOUTHERN NEVADA FOR ISOLATED TO SCATTERED SHOWERS. IT APPEARS AREAS FROM I-15 EASTWARD WILL BE FAVORED. UPDATED THE FORECAST TO REFLECT THESE TRENDS. && .PREV DISCUSSION...312 AM PDT THU OCT 5 2006... .SHORT TERM...ISOLATED RAIN SHOWERS/THUNDERSTORMS CURRENTLY OCCURRING ACROSS EASTERN SAN BERNARDINO...CLARK AND SOUTHEAST LINCOLN COUNTIES. THE LATEST RAPID UPDATE CYCLE (RUC) DOES PICK INDICATE A WEAK SHORTWAVE EMBEDDED IN THE MOISTURE SOUTHWEST FLOW. THE RUC QUICKLY SHIFTS THE FEATURE NORTHEAST INTO LINCOLN COUNTY OVER THE NEXT THREE HOURS WITH SHOWERS TAPERING OFF ACROSS CLARK/EASTERN SAN BERNARDINO COUNTIES BY DAYBREAK. LATEST MODEL GUIDANCE SLOWS THE PROGRESSION OF UPPER LOW NEAR THE CENTRAL CALIFORNIA COAST TODAY KEEPING THE SYSTEM NEARLY STATIONARY. THE EASTERN HALF THE AREA WILL STAY UNDER A MOIST SOUTHWEST FLOW WITH ANY MINOR DISTURBANCES KICKING OFF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS MAINLY FROM THE COLORADO RIVER EAST. WITH THE SLOWER TIMING THE TROUGH IS STILL OVER SOUTHERN CALIFORNIA LATE FRIDAY MORNING WITH STRONG SHORTWAVE EJECTING NORTHEAST ACROSS SOUTHERN NEVADA FRIDAY AFTERNOON. STRONG DYNAMICS ASSOCIATED WITH TROUGH WILL INCREASE LARGE SCALE ACCENT OVER THE EASTERN THIRD OF THE AREA STARTING AFTER MIDNIGHT WITH BEST FOCUS STILL OVER FAR EASTERN CLARK....MOHAVE AND LINCOLN COUNTIES ON FRIDAY. MODEL QPF HIGHER TONIGHT OVER NORTHERN MOHAVE/LINCOLN COUNTIES WITH A FEW SPOTS POSSIBLY GETTING UPWARDS OF 1.0 TO 1.25 INCHES OF RAIN. CONDITIONS SHOULD RAPIDLY APPROVE FRIDAY EVENING AS SHORTWAVE EJECTS NORTHEAST THROUGH UTAH. HOWEVER...UPPER TROUGH WILL REMAIN OVER THE SOUTHERN GREAT BASIN AND MOJAVE DESERT SATURDAY AS ADDITIONAL SHORTWAVE ENERGY DIGS DOWN BACKSIDE. WITH LITTLE MOVEMENT OF MAIN LOW ALONG THE CENTRAL CALIFORNIA COAST NOT LOOKING FOR MUCH TEMPERATURE CHANGE FROM YESTERDAY WITH THE COOLING HAPPENING FRIDAY AND SATURDAY. .LONG TERM...FOR THE PERIOD SUNDAY THROUGH THURSDAY THE IMPROVING MODEL TREND MENTIONED BY THE PREVIOUS SHIFT CONTINUES HELPING TO GIVE A BIT MORE CONFIDENCE WITH THE PACKAGE TONIGHT. ALL MEMBERS START OUT SUNDAY IN GOOD AGREEMENT WITH A CLOSED LOW JUST OF THE SOUTHERN CALIFORNIA COAST AND AN OMEGA BLOCK AXIS STRETCHING FROM TEXAS INTO MICHIGAN. FROM THAT POINT...THE SOLUTIONS SLOWLY START TO SLOWLY DIVERGE. GFS/EUROPEAN SLIGHTLY RETROGRADE THE LOW WHILE THE DGEX IS MORE PROGRESSIVE AND BRINGS IT INTO SOUTHERN NEVADA BY MONDAY. MODELS HAVE HISTORICALLY DONE A POOR JOB WITH CUT-OFF LOWS OFF THE COAST SO VERY DIFFICULT TO PICK WHICH SOLUTION IS MORE LIKELY. FOR NOW TENDED TO SIDE WITH THE SLOWER TRACK OF THE EUROPEAN/GFS WHICH WILL LEAD TO INCREASING MOISTURE ENTERING THE CWA FROM THE SOUTHEAST BY MONDAY. THE POSITION OF THE LOW WILL OBVIOUSLY DICTATE MORE LIKELY LOCATIONS FOR ANY PRECIPITATION SO WENT WITH A SLIGHT CHANCE IN MANY AREAS AND A CHANCE IN HIGHER ELEVATIONS ON MONDAY. LIFTED VALUES PROGGED TO BE AS LOW AS MINUS 2 SO POTENTIAL IS THERE FOR SOME GOOD CONVECTIVE ACTIVITY ON MONDAY. TUESDAY GIVES SIMILAR LIFTED VALUES BUT MADE THE CHANCES SLIGHTLY LESS DUE TO UNCERTAINTY WITH THE FORECASTED TRACK. KEPT A MENTION OF SHOWERS THROUGH THE REST OF THE EXTENDED AS GFS STILL HAS THE LOW OVER CALIFORNIA THROUGH WEDNESDAY. HIGH TEMPERATURES STILL EXPECTED TO BE A BIT BELOW NORMAL SO TRENDED THEM BELOW SUGGESTED GUIDANCE AND CLOSER TO ENSEMBLE AVERAGE. NIGHT TIME LOWS VERY TRICKY IN THIS TYPE OF A PATTERN AS CLOUD COVER DUE TO THE SYSTEM MAY BOOST THEM HIGHER THAN EXPECTED. && .AVIATION...TAFS AND TWEBS ADEQUATELY DESCRIBE EXPECTED WEATHER CONDITIONS FOR AREA TERMINALS. SEE TAFS FOR KLAS...KVGT...KDRA... KBIH...KDAG...KEED FOR DETAILS. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .VEF WATCHES/WARNINGS/ADVISORIES... .NV...NONE. .AZ...NONE. .CA...NONE. $$ PIERCE/BELL HTTP://WEATHER.GOV/LASVEGAS nv AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NASHVILLE TN 923 AM CDT THU OCT 5 2006 .UPDATE... YESTERDAY'S HIGH OF 89 DEGS IN NASHVILLE CAME WITHIN 2 DEGREES OF THE RECORD HIGH FOR OCT 4TH WHICH IS 91 DEGS SET BACK IN 1884. INDIAN SUMMER WILL END TODAY AS A COLD FRONT WORKS ACROSS THE MID STATE BRINGING A CHANCE FOR SHOWERS...AND A FEW THUNDERSTORMS...ALONG WITH COOLER TEMPS. DOPPLER RADAR IS SHOWING SCATTERED THUNDERSTORMS BEGINNING TO WORK DOWN INTO NORTHWEST MIDDLE TN AT MID-MORNING. RUC MODEL KEEPS THIS ACTIVITY SCATTERED DURING THE DAY AS IT LUMBERS ACROSS THE MID STATE. CURRENT FORECAST LOOKS ON TRACK AND SEE NO REASON TO MAKES ANY CHANGES AT THIS TIME. BOYD && .PREV DISCUSSION... (ISSUED 247 AM CDT THU OCT 5 2006) DISCUSSION... SFC COLD FRONT APPEARS TO BE ALONG A LINE FROM WRN KY TO NORTH CNTRL AR. FRONT APPEARS TO BE MOVING SEWD AT 20 MPH. THE "FINE LINE" THAT APPEARS ON KOHX BASE REFLECTIVITY MOVING THROUGH THE NASHVILLE AREA APPEARS TO BE SOME SORT OF PRE-FRONTAL TROUGH. AT UPPER LEVELS...AN H5 RIDGE IS CENTERED OVER THE SRN PLAINS. A BROAD TROUGH IS SEEN OVER CANADA AND NEW ENGLAND. A DEEP TROUGH IS SEEN OVER WEST COAST. WRF MODEL EXPECTS THE COLD FRONT TO PASS THE NASHVILLE AREA BETWEEN 8 AM AND 9 AM AND THE CLARKSVILLE AROUND 2 PM. MODEL ALSO SHOWS PRECIPITATION INCREASING MAINLY OVER THE SERN PORTION OF THE MIDSTATE DURING THE AFTERNOON. PRECIP IS THEN PUSHED EAST OF THE PLATEAU AFTER 10 PM. MESOETA INSTABILITY PARAMETERS INDICATE THAT TSTMS ARE POSSIBLE...MAINLY IN THE SERN HALF OF THE AREA THIS AFTERNOON. SFC RIDGE OCCUPIES THE MIDSTATE THROUGH THE WEEKEND AS A SFC LOW DEVELOPS ALONG THE EAST COAST. THIS IS IN RESPONSE TO AN H5 TROUGH THAT DIVES SEWD ACROSS THE APPALACHIANS AND GENERATES AN H5 LOW OVER THE CAROLINAS THAT EVENTUALLY GETS KICKED OUT TO SEA. ANOTHER COLD FRONT DIVES SEWD ACROSS THE OHIO VALLEY ON MON BUT WEAKENS SGFNTLY BECOMING VERY DIFFUSE WHEN REACHING THE MIDSTATE. A SECOND FRONT FOLLOWS ON WED WITH MUCH MORE DEFINITION AND A SLGT CHC FOR PRECIP ON WED NGT AND THU. MOS TEMPS AND POPS ARE IN REASONABLE AGREEMENT AND NO SGFNT DEVIATIONS ARE PLANNED. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ BOYD tn AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 1015 AM CDT THU OCT 5 2006 .DISCUSSION...ISOLATED MARINE CONVECTION CONTINUES TO ADVECT INTO DEEP SOUTH TEXAS AND NORTHEASTERN MEXICO FROM THE TROPICAL WAVE LOCATED OVER THE SOUTHWESTERN GULF. THE LATEST RUC GUIDANCE KEEPS THIS FEATURE SUPPRESSED TO THE SOUTH AND WILL GRADUALLY SHIFT WESTWARD OVER TODAY AND FRIDAY. THE 12Z BRO SOUNDINGS SHOWS THAT THE MORNING PWAT OVER THE CWA HAVE DROPPED PRETTY SIGNIFICANTLY WITH A MORNING VALUE ONLY AROUND 1.6 INCHES IN COMPARISON TO YESTERDAY. THIS APPEARS TO BE DUE TO THE BUILDING 500 MB RIDGING OVER THE SOUTH CENTRAL PLAINS STATES. ALSO VSBL SATELLITE IMAGERY SHOWS A LARGER AREA OF FOG AND LOW STATUS POSITIONED JUST TO THE NORTH OF THE BRO CWA AND THIS SHOULD NOT POSE MUCH OF A THREAT TO THE AREA AND SHOULD BEGIN TO ERODE AWAY LATER THIS AFTERNOON IN RESPONSE TO THE AFTERNOON HEATING. SO CONSIDERING ALL OF THIS...20 TO 30 PERCENT POPS LOOK OK FOR THE FIRST PERIOD OF THE ZFP AND DO NOT EXPECT ANY MAJOR CHANGES AT THIS TIME. && .MARINE...BUOY 42020 REPORTED NORTHEAST WINDS NEAR 12 KNOTS GUSTING TO NEAR 14 KNOTS WITH SEAS SLIGHTLY OVER 4.5 FEET WITH A PERIOD OF 8 SECONDS AT 09 CDT/14 UTC. BROAD SURFACE LOW PRESSURE OVER THE BAY OF CAMPECHE WILL INTERACT WITH HIGH PRESSURE OVER THE NORTHERN GULF OF MEXICO THROUGH THE NEXT SEVERAL DAYS. THIS INTERACTION WILL PRODUCE MODERATE WINDS AND SEAS ALONG THE LOWER TEXAS COAST THROUGH EARLY NEXT WEEK. && .AVIATION...VFR/MVFR CONDITIONS WILL PREVAIL AT THE TRIO OF REGIONAL AIRPORTS THROUGH THE NEXT 24 HOURS WITH PARTLY TO MOSTLY CLOUDY SKIES AND SCATTERED SHOWERS AND THUNDERSTORMS. && .BRO WATCHES/WARNINGS/ADVISORIES...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT: HTTP://WWW.SRH.NOAA.GOV/BRO SYNOPTIC/GRIDS...60 MARINE/AVIATION...66 MESO...ABBOTT tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 1040 AM EDT THU OCT 5 2006 .SHORT TERM /REST OF TODAY/... MINOR TWEAKS TO MRNG UPDATE. HAVE BUMPED UP MAX TEMPS SLGTLY IN A FEW AREAS AND ADJUSTED POPS TO 30 FOR WRN/CNTRL CNTIES AND 20 FOR ERN CNTIES. && .PREV DISCUSSION... (ISSUED 342 AM EDT THU OCT 5 2006) ..UNSEASONABLY COOL / WET & POTENTIALLY STORMY PRD AHEAD... SHORT TERM /TODAY THROUGH SATURDAY/... FIRST THINGS FIRST. PNTNL EXISTS FOR HVY RNFL ACROSS FA (2-4 IN AVG WITH PTNTLLY HIGHER AMTS ALONG THE COAST). SINCE QPF WILL BE OBSERVED OVR A LONG PRD OF TIME...HAVE DECIDED TO ISSUE AN ESF RTHR THAN POST A FLOOD WATCH. LATER SHIFTS CAN EVALUATE NEED FOR A FLOOD WATCH. CDFRNT RUNNING ABT 1-3 HRS BEHIND MODELS. THIS ALRDY MAKES FOR A COMPLICATED TMP FCST AS SOME CRNT READINGS ARE HIGHER THAN FCSTD MAX TMPS ACROSS NRN HALF OF FA. PCPN ASSCTD WITH FROPA MAINLY BEHIND BDNRY IS TENDING TO DSPT PAST FEW HRS. THUS TDYS POPS WILL BE HIGHEST ACROSS WRN CNTYS. FRNT PROGGED JUST S OF VA/NC BRDR BY 18Z. BY THEN...ENUF HEATING INDCTG AHEAD & ALONG BNDRY TO MAKE AIRMASS MARGINALLY UNSTABLE. THUS...HAVE TRIMMED BACK THUNDER CHC TO XTREME SW CNTYS THIS AFTRN. WILL TRY TO CONVEY STDY OR SLOWLY FALLING TMPS ACROSS NRN CNTYS THIS AFTRN IN GRIDS. LEANED TOWARD GFS SOLN THRU FRI. BNDRY SAGS WELL S INTO NC BY 00Z. VORT MAX PROGGED TO MOVE E ALONG BNDRY WILL HAVE TROF XTNDG N ALONG MTS TONITE. XPCT PCPN TO RAPIDLY DVLP W-E ACROSS RGN THIS EVE. ENUF LIFT/OMEGA PROGGED FOR SOME EMBEDDED AREAS OF HVY RAIN AFTR 06Z ACROSS PIEDMONT AREAS. SO...BASICALLY INCRSD CATEGORICAL POPS ALL AREAS LATE TONITE AND FRI. UPR LVL NRGY DIVES SE FRI IN DVLPNG ERN TROF. SAID NRGY SPAWNS CSTL LOW IVOF HAT. AIRMASS CONTS TO BE SATURATED ENUF TO SPRT CATEGORICAL POPS AGAIN. CAVEAT TO THIS EVENT WILL BE HOW MUCH TRPLCL MSTR (THAT IS LURKING OFF SE COAST) GETS ENTRAINED AS SYSTM GETS CUT-OFF. MODELS AGREE THAT ENUF OF THIS MSTR GETS WRAPPED ARND INTO SERN CSTL AREAS FOR SOME HVY RNFLL FRI INTO FRI NITE. CAA KEEPS TMPS FROM GOING NOWHERE WITH INLAND READINGS REMAINING IN THE 50S...SOME 30 DEGREES COLDER THAN YSTRDYS HIGHS IN THE 80S. BY FRI NITE SYSTM BEGINS TO SLOWLY DRIFT S. AS PER DSCNS...THNK GFS NWRD JOG LATE FRI NITE INTO ERLY SAT IS SUSPECT...SO WILL KEEP TRACK MORE TOWARD THE NAM (FRTHR S). LOWS IN THE 40S AND 50S SE. PTNTL FOR SOME ELVTD CONVECTION ALONG SE CSTL AREAS...THIS ALL DEPENDS ON EXACT LCTN OF LOW. WILL NOT MENTION THUNDER CHC ATTM... SINCE CONFIDENCE IS LOW. SYSTM DRIFTS S INTO CAROLINAS SAT...BUT TSCTNS STILL LOADED WITH ENUF MSTR FOR LIKELY OR HIGHER POPS. HOWEVER...THNK PCPN COMES LGHTR AND SPOTTY IN NATURE. TMPS U50S-L60S. LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... LOW THEN BEGINS TO LIFT NE SAT NITE AND SUN. HAVE KEPT CHC POPS (SHWRS) IN FOR NOW...ALL DEPENDS OF HOW CLOSE TO COAST LOW TRACKS. LEFT OF FCST LEFT UNCHANGED. AVIATION... INITIAL VFR CONDITIONS AHEAD OF THE FRONT. TIMING THE FRONT USING THE RUC WHICH IS A COUPLE HOURS SLOWER THEN GFS OR NAM. NOT A LOT OF CLOUDS INITIAL WITH FRONT SO MAINLY MID TO HIGH CLOUDS DURING THE DAY. ALL MODELS AGREE WITH DIGGING UPPER SYSTEM STRONG DIVG DEVELOPS OVER THE SW PART OF THE AREA FIRST AND THIS BREAKS OUT RAIN TONIGHT. BUFKIT SOUNDINGS SHOW A LAYER OF HIGH RH DEVELOPING NEAR THE COAST AND MOVING INLAND AT SUNSET. WHILE CONDITIONS WILL LOWER WAS SLOWER WITH THE LOWERING OF CONDITIONS. DO BRING IFR TO MOST TAFS BETWEEN 03Z AND 06Z ONLY ECG WILL BE LATER. MARINE... INITIAL SURGE AS THE FRONT PUSHES THROUGH TODAY WILL PRODUCE SMALL CRAFT CONDITIONS ON THE BAY. WAVES WILL ALSO INCREASE ON THE COASTAL WATERS WITH SMALL CRAFT CONDITIONS DEVELOPING THERE BY AFTERNOON. THE NORTHERN PART OF THE BAY WINDS WILL DIMINISH IN THE AFTERNOON. ALL THIS IS WELL BEFORE THE MAIN EVENT. WILL LEAN TOWARD THE MORE SOUTHERN AND OFFSHORE POSITION OF THE NAM LOW. THIS STILL WILL COMBINE WITH THE HIGH TO THE N TO GENERATE GALE FORCE WINDS DEVELOPING ON FRIDAY AND CONTINUING INTO SAT. WHILE THERE STILL IS SOME UNCERTAINTY OF THE LOCATION OF THE LOW ALL MODELS DO TO DEVELOP ENOUGH GRADIENT TO WARRANT GALES. ALSO WITH THE NE WINDS AND HIGH ASTRONOMICAL TIDES CAN HAVE THE POTENTIAL FOR MINOR TO MODERATE COASTAL FLOODING DURING THE HIGH TIDES FRIDAY AFTERNOON AND SATURDAY MORNING. ALL MODELS SHOW HIGH WEAKENING TO THE N ON SUNDAY AND LOW MOVING S THIS WILL RELAX THE GRADIENT BY THEN. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...COASTAL FLOOD WATCH FOR MDZ025 FROM 2 PM FRIDAY TO 2 PM SATURDAY. NC...NONE. VA...COASTAL FLOOD WATCH FOR VAZ095-098>100 FROM 2 PM FRIDAY TO 2 PM SATURDAY. MARINE...SMALL CRAFT ADVISORY FOR ANZ630-631 UNTIL 2 PM THURSDAY. ...SMALL CRAFT ADVISORY FOR ANZ632-650-652 UNTIL 8 AM FRIDAY. ...SMALL CRAFT ADVISORY FOR ANZ633 UNTIL 6 PM THURSDAY. ...SMALL CRAFT ADVISORY FOR ANZ654-656-658 FROM 6 PM THURSDAY TO 8 AM FRIDAY. && $$ SHORT TERM...GINGRICH va AREA FORECAST DISCUSSION...CORRECTION NATIONAL WEATHER SERVICE DODGE CITY KS 254 AM CDT FRI OCT 6 2006 .DISCUSSION... DAYS 1-2... MADE ONLY A FEW MINOR TWEAKS TO THE GOING FORECAST. UPPER RIDGE CENTERED OVER WESTERN OKLAHOMA THIS MORNING WILL GRADUALLY SHIFT EAST OVER THE NEXT COUPLE OF DAYS AS THE ENERGY IN THE SOUTHWEST MERGES WITH A NORTHERN STREAM SHORTWAVE TROF AND MOVES EAST ACROSS THE NORTHERN US. THIS WILL BRING A FRONT SOUTH INTO WESTERN KANSAS BY LATE SATURDAY NIGHT INTO SUNDAY. UNTIL THIS HAPPENS THE WEATHER WILL REMAIN WARM AND TRANQUIL ACROSS WESTERN KANSAS. WINDS WILL BE QUITE BREEZY THE NEXT COUPLE OF DAYS AS THE PRESSURE GRADIENT STRENGTHENS BETWEEN A DEVELOPING LEE TROF OVER EASTERN COLORADO AND HIGH PRESSURE OVER THE GREAT LAKES. AFTER LOOKING AT THE RUC AND NAM WINDS IT APPEARS THE BETTER CHC OF REACHING SUSTAINED ADVISORY CRITERIA TODAY WILL BE NORTH AND WEST OF MY CWA. A BETTER CHC OF REACHING ADVISORY WINDS IN MY CWA MAY BE ON SATURDAY. THE GFS AND UKMET ARE IN PRETTY GOOD AGREEMENT AND ARE SLIGHTLY FASTER THAN THE NAM IN BRINGING THE FRONT INTO NORTHERN KANSAS LATE SATURDAY NIGHT. THERE MAY BE AN ISOLATED SHOWER OR STORM ALONG THE FRONT, BUT GIVEN THE LACK OF GOOD MOISTURE AND THE TIME OF DAY WILL KEEP ONLY 10 POPS IN FOR LATE SATURDAY NIGHT UP NORTH. LACY DAYS 3-7... FORECAST CHALLENGES IN THIS EXTENDED PERIOD ARE TEMPERATURES WITH SECONDARY STRONG COLD FRONT ON WEDNESDAY. NEW GFS AND EC BRING DOWN COLD 850MB TEMPS FROM 0C TO 4C BY WEDNESDAY AFTERNOON AND BELOW ZERO ON THURSDAY. THIS IS WITH STRONG UPPER LOW FORECAST TO DIVE INTO THE GREAT LAKES. HAVE LOWERED HIGHS WITH THIS SOLUTION IN MIND. DO NOT THINK WILL BE AS COLD ON THURSDAY AS GFS ADVERTISES AT -7C WITH NEW EC PUSHING UPPER TROUGH EAST. OTHER CHALLENGES ARE LINGERING RAIN CHANCES IF PIECES OF UPPER LOW OVER THE WEST CONUS PUSH OUT AS GFS SHOWS. 06 && .PRELIMINARY POINT TEMPS/POPS... DDC 83 60 86 61 / 0 0 0 10 GCK 84 61 85 60 / 0 0 0 10 EHA 83 60 84 57 / 0 0 0 10 LBL 84 61 86 59 / 0 0 0 10 HYS 83 61 88 61 / 0 0 0 10 P28 84 59 87 62 / 0 0 0 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ FN27/06 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PADUCAH KY 318 AM CDT FRI OCT 6 2006 .DISCUSSION... IR LOOP SHOWS LOW CLOUDS HANGING ON OVER SOUTHERN PORTIONS OF WESTERN KENTUCKY. RUC CONTINUES TO INDICATE THAT THIS AREA OF CLOUDS WILL CONTINUE TO SLIDE SOUTH OUT OF THE AREA. MAY HAVE TO MAKE LAST MINUTE ADJUSTMENTS FOR TIMING. WATER VAPOR LOOP INDICATES VERY DRY AIR IS MOVING SOUTH INTO THE REGION...WHICH HAS BEEN VERY WELL ADVERTISED BY THE MODELS. THE SHORT WAVE MOVING SOUTH AHEAD OF THE DRY AIR IS EXPECTED TO DEEPEN INTO AN UPPER LEVEL LOW IN THE SOUTHEAST U.S. BY LATER TODAY. THIS ALONG WITH THE DIGGING UPPER LOW OFF THE SOUTHERN CALIFORNIA COAST WILL RESULT IN A BLOCKING PATTERN FOR OUR REGION. THE RIDGE OVER THE CENTRAL U.S. WILL MOVE EAST AND SETTLE OVER THE LOWER OHIO VALLEY. THE RESULT WILL BE DRY AND MILD WEATHER FOR THE NEXT 4 DAYS. ALL MODELS AND ENSEMBLE MEMBERS ARE IN PRETTY GOOD AGREEMENT WITH THE SHORT TERM AND WITH SOME OF THE EXTENDED. MODELS SUGGEST THE RIDGE WILL BREAK DOWN DURING THE MIDDLE OF THE WEEK. LATEST RUNS HAVE THINGS SPEEDED UP A BIT. EACH OF THE LAST THREE MODEL RUNS HAVE BEEN INCREASING POPS FOR WEDNESDAY...SO INTRODUCED A SLIGHT CHANCE STARTING AFTER MIDNIGHT TUESDAY. MADE GENERALLY MINOR ADJUSTMENTS TO TEMPERATURES. WENT WITH WARMER GUIDANCE NUMBERS ON SUNDAY WITH 14 DEGREE C 850 TEMPERATURES EXPECTED OVER THE AREA. && .PAH WATCHES/WARNINGS/ADVISORIES... KY...NONE. MO...NONE. IL...NONE. IN...NONE. && $$ SPODEN ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 443 AM EDT FRI OCT 6 2006 .SYNOPSIS... 07Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWS A RIDGE COVERING MUCH OF THE CENTRAL PLAINS...AND DEEP TROUGHS ALONG THE WEST COAST AND ACROSS EASTERN CANADA/LOWER GREAT LAKES. SEVERAL SHORTWAVES TO NOTE ARE ACROSS THE INTERMOUNTAIN WEST IN THE UPSTREAM FLOW. THESE SHORTWAVES ARE RESPONSIBLE FOR SURFACE LOW PRESSURE OVER CO THAT WILL INFLUENCE OUR WEATHER THIS WEEKEND. HIGH PRESSURE HAS MOVED EAST OF OUR CWA...WITH RETURN FLOW NOW PRESENT AND OVERNIGHT TEMPS OVER MANY AREAS HAVE FALLEN INTO THE LOWER 30S. KINL/KMPX SNDGS INDICATE VERY DRY AIR ACROSS THE ENTIRE PROFILE. IR SAT SHOWS HIGH CLOUD FROM THE UPSTREAM SHORTWAVE REACHING AREAS OF WESTERN MN. THE LAND BREEZE HAS KICKED IN ALONG THE LAKE SUPERIOR SHORELINE...WARMING TEMPS A FEW DEGREES. && .SHORT TERM (TODAY AND TONIGHT)... UPPER LEVEL RIDGING CENTERED OVER WESTERN MINNESOTA WILL BUILD INTO UPPER MICHIGAN TODAY...ALLOWING WARMER AIR OBSERVED OVER THE PLAINS YESTERDAY TO MOVE IN. IN FACT...THE GFS SUGGESTS 850MB TEMPS RISING TO 8-12C BY 00Z...WARMEST WEST. GIVEN THAT TODAY THERE WILL BE PLENTY OF SUNSHINE...THANKS TO THE SUBSIDENCE FROM THE UPPER LEVEL RIDGE AND LOW LEVEL DRY AIR ASSOCIATED WITH THE SURFACE HIGH PRESSURE AREA...WE SHOULD MIX AT LEAST UP TO 900MB OR PERHAPS SLIGHTLY HIGHER. THIS YIELDS HIGHS IN THE LOW TO MID 60S...WHICH IS CLOSE TO THE GOING FORECAST AND SIMILAR TO MET GUIDANCE. THE WARM ADVECTION IS PROGGED TO CONTINUE TONIGHT...AND WILL ALSO BE STRONGER DUE TO PRESSURES FALLING IN THE PLAINS IN ADVANCE OF A STRONG SHRTWV LIFTING OUT OF THE SW. MODELS SHOW 850MB WINDS INCREASING OVER MN AND WESTERN WISCONSIN TO 40 KT OUT OF THE SW. THIS WARM ADVECTION IS ALSO SEEN ON 800-700MB FRONTOGENESIS PLOTS FROM THE NAM/GFS ACROSS WESTERN LAKE SUPERIOR INTO WESTERN UPPER MICHIGAN. THE INCREASING FRONTOGENESIS...COMBINED WITH ADVECTING IN UNSTABLE AIR FROM THE PLAINS (NOTED BY NEGATIVE EPV VALUES IN CROSS SECTIONS)...SHOULD RESULT IN THE DEVELOPMENT OF AN ACCAS DECK ACROSS THE WEST HALF OF THE CWA DURING THE NIGHT. SINCE THE FORCING WITH THE FRONTOGENESIS LOOKS FAIRLY STRONG...NOTED BY A NEARLY VERTICAL AGEOSTROPHIC CIRCULATION...AND THAT THE FRONTOGENESIS/NEGATIVE EPV AREA IS SATURATED...HAVE BOTH RAISED AND EXPANDED POPS SOME FOR TONIGHT. THE INCREASING WINDS SHOULD ALSO ALLOW TEMPERATURES FROM DROPPING AS MUCH AS THEY HAVE DONE THE PAST FEW NIGHTS...AND THEREFORE HAVE WENT CLOSER TO THE WARMER 13 KM RUC AND MAV GUIDANCE. THE MET GUIDANCE LOOKED TOO COOL. GIVEN THE LOW LEVEL JET IS COMPOSED OF SW WINDS...WHICH DOWNSLOPES ALONG LAKE SUPERIOR...LAKE SUPERIOR LOCATIONS WILL LIKELY BE BREEZY TONIGHT. GUSTS GRIDS REFLECT THIS. .LONG TERM (SATURDAY THROUGH TUESDAY)... SAT...MODEL SOUNDINGS LOOK A BIT TOO COOL TONIGHT FOR THE AMOUNT OF RADIATIONAL COOLING EXPECTED...THEREFORE TEMPS WILL BE WARMER THAN MODEL GUIDANCE. HOWEVER...CURRENT THINKING IS THAT FCST MAX TEMPS SAT MAY HAVE BEEN A LITTLE OVERDONE...ESPECIALLY ACROSS THE INTERIOR WEST. IF SKIES ARE CLEAR TONIGHT...RADIATIONAL COOLING MAY CAUSE TEMPS TO BE VERY LOW SATURDAY MORNING. MODEL SNDGS INDICATE SFC TEMPS DOWN TO AROUND 5C IN IMT. IF THIS PANS OUT...IT WOULD BE DIFFICULT FOR THE TEMPS TO RISE MUCH HIGHER THAN THE LOWER 70S. MAX TEMPS ALONG THE LAKE SUPERIOR SHORELINE SHOULD BE OK SINCE THERE WILL BE LESS RADIATIONAL COOLING AND DOWNSLOPING WINDS. AS FOR MIXING...GFS/NAM MODEL SNDGS SHOW A DRY PROFILE AND A MIXING HEIGHT AROUND 2500FT. THIS GIVES MIXING UP TO AROUND 900MB...WHICH GIVES SFC TEMPS OF AT LEAST 65F. WITH MOSTLY SUNNY SKIES AND DOWNSLOPING WINDS...CONFIDENT WITH MAX TEMPS IN THE 70S ACROSS MOST OF OUR CWA. FIRE WX MAY BE A CONCERN. SAT NIGHT...RADIATIONAL COOLING WILL NOT BE AS PREVALENT...WITH BREEZY CONDITIONS AND INCREASING CLOUDS FROM THE WEST DUE TO THE UPSTREAM LOW PRESSURE SYSTEM. KEPT LOW TEMPS IN THE MID TO UPPER 50S ACROSS THE WEST AND THE LAKE SUPERIOR SHORELINE...AND IN THE LOWER 50S ELSEWHERE. SUN THROUGH MON...THE SFC COLD FRONT IS EXPECTED TO MAKE ITS WAY ACROSS OUR CWA BEGINNING AROUND 12Z. 850-700MB LAPSE RATES GET UP TO 7.25C ACROSS THE WESTERN U.P. IN THE MORNING...THEN STABILIZE AFTER THE SFC FROPA. CHANGED WX TO A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS SUN MORNING WEST HALF...THEN KEPT THE CHANCE OF SHOWERS FOR THE WHOLE CWA IN THE AFTERNOON TO ACCOUNT FOR THE UPPER LEVEL FROPA. GFS/NAM SNDGS SHOW 850MB TEMPS STEADILY WARMER THAN THE SFC UNTIL 00Z MON. KEPT SUN MAX TEMPS WITH GOING FCST IN THE UPPER 60S. SUN NIGHT DECREASED MIN TEMPS A DEGREE OR TWO TO ACCOUNT FOR DECREASING CLOUDS...WENT WITH HPC/GFS COOP MOS BLEND. MON...LOWERED HIGHS EAST TO ACCOUNT FOR EXPECTED LAKE EFFECT CLOUDS WITH THE STIFF NW WIND ACROSS LAKE SUPERIOR. NOT EXPECTING LAKE EFFECT SHOWERS BEHIND THE FRONT DUE TO AIR THAT IS TOO DRY. FOR TUE THROUGH THU...NORMALLY DO NOT WORK ON THE EXTENDED ON THIS SHIFT...BUT LOOKING AT THE ECMWF AND UKMET AND GFS...HAD TO LOWER TEMPERATURES ON WED AND THURSDAY DRASTICALLY AND ALSO HAD TO INTRODUCE A CHANCE OF RAIN OR SNOW SHOWERS FOR WED NIGHT AND THU ACROSS THE WEST HALF. THE GFS AND ECMWF ALL SHOW 850 MB TEMPERATURES DROPPING TO BELOW -10C AND WITH LAKE TEMPERATURES BEING AROUND 11C-15C...THIS IS ENOUGH FOR A LAKE EFFECT PRECIPITATION EVENT. PROBLEM IS THAT BOTH THE GFS AND ECMWF ALL SHOW A WOUND UP SYSTEM WITH A DRY SLOT AND OCCLUDED FRONT WORKING THROUGH AND THE WINDS BECOMING MORE WESTERLY OR EVEN SOUTHWESTERLY WITH COLD AIR ADVECTION ON WED NIGHT AND THU. WILL GO CHANCE POPS FOR NOW. IT IS ALSO HARD TO FIGURE OUT IF THERE WILL BE A RAIN/SNOW MIX ON THU OVER THE EAST. 1000-850 MB THICKNESS WILL NOT WORK WELL BECAUSE IT IS EARLY IN THE SEASON AND THE 1305 METER THICKNESS RULE OF 1000-850 MB DOES NOT WORK WELL EARLY IN THE FALL AND WINTER SEASON. WILL GO WITH THE WEST HALF AS THE MOST LIKELY CANDIDATE FOR THE RAIN/SNOW MIX WITH ELEVATION A KEY PLAYER AND THE WEST WILL BE ENTRENCHED IN THE COLD AIR LONGER THAN THE EAST HALF. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ MRC/AJ/GM mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 305 AM EDT FRI OCT 6 2006 .SYNOPSIS... WATER VAPOR IMAGERY AND 00Z RAOBS INDICATED AN UPPER LOW ALONG THE CENTRAL CALIFORNIA COAST...WITH A PLUME OF PACIFIC MOISTURE MOVING NORTH ACROSS THE ROCKIES...WHERE PW VALUES ACROSS THE CENTRAL ROCKIES (SLC/RIW/GJT) WERE OVER 200 PERCENT OF NORMAL. CLOSER TO HOME...A DIGGING UPPER LEVEL TROUGH WAS TRACKING THROUGH THE GREAT LAKES REGION...WITH ALL MODELS INDICATING A CUTOFF UPPER LOW DEVELOPING OVER THE CENTRAL APPALACHIANS/SOUTHEAST CONUS LATER TODAY. THIS WILL SET UP A PSEUDO OMEGA BLOCK PATTERN INTO THE FIRST HALF OF THE WEEKEND...WITH THE CENTRAL GREAT LAKES UNDERNEATH THE DRY RIDGE AXIS. THE ONLY REAL CONCERN TO THE SENSIBLE WEATHER THROUGH THE WEEKEND IS WHETHER OR NOT LOW STRATUS WILL BE ABLE TO DEVELOP UNDERNEATH THE SUBSIDENCE INVERSION...AS TYPICALLY OCCURS DURING FALL. GFS/NAM SOUNDINGS INDICATING LOW INVERSION HEIGHTS...4000 FEET OR LESS...WHICH SHOULD MAKE IT AWFULLY TOUGH WITH THE LIMITED LOW LEVEL MOISTURE IN PLACE. HOWEVER...THE NAM IS INDICATING EASTERLY FLOW COMING OFF OF LAKE ERIE WILL EVENTUALLY LEAD TO LOW STRATUS ACROSS THE SOUTH HALF OF THE CWA COME FRIDAY NIGHT...BASED ON THE HIGH 925 MB RH INDICATED. 00Z GFS IS DRIER (925 MB RH RISING INTO THE 60 PERCENT RANGE)...AND IS PREFERRED WITH THE USUAL MOIST BIAS OF THE NAM IN THE LOW LEVELS. NOT TO MENTION 850 MB TEMPS ARE RELATIVELY WARM (8 C) AND THE LOW LEVEL FLOW LOOKS WEAK. FEW IF ANY CHANGES MADE TO THE TEMPS THIS WEEKEND...AS THEY ARE IN LINE WITH THE GFS MOS GUIDANCE AND APPEAR REASONABLE. ANOTHER FROST ADVISORY APPEARS LIKELY FOR TONIGHT WITH THE SURFACE HIGH LINGERING. RETURN FLOW OVER THE WEEKEND WILL ALLOW FOR A WARMUP...WITH SUNDAY SHAPING UP TO BE THE WARMEST DAY (LOW TO MID 70S) OF THE FORECAST PERIOD OUT AHEAD OF APPROACHING COLD FRONT...WHICH HAS THE POTENTIAL OF COMING THROUGH DRY SUNDAY NIGHT/MONDAY WITH WEAK FRONTAL CONVERGENCE...WARM MID LEVELS/CAP...AND LACK OF UPPER LEVEL FORCING (WHICH MOVES INTO ONTARIO). NEXT WEEK IS THEN EXPECTED TO FEATURE ANOTHER MAJOR PATTERN SHIFT...AS POLAR VORTEX SETS UP SHOP OVER/NEAR HUDSON BAY (PER 12Z EUROPEAN/00Z GLOBAL) WITH A SOUTHWARD EXTENSION...DELIVERING POTENTIALLY THE FIRST SHOT OF ARCTIC AIR AND SNOW SHOWERS TO THE REGION DURING THE MID TO LATE WEEK PERIOD. THE 00Z GFS/EUROPEAN ARE SIGNIFICANTLY FARTHER SOUTHWEST/SLOWER WITH THE COLD CORE...AND THUS HAVE ONLY MADE A SLIGHT DOWNWARD ADJUSTMENT TO DAY 7 MAXES FOR NOW. && .PREV DISCUSSION...ISSUED 105 AM EDT FRI OCT 6 2006 AVIATION... SATELLITE IMAGERY VERY LATE IN EVENING SHOWS SOUTHEAST MI NEARLY FREE OF CLOUDS...THE MAIN CLOUDS BEING SMALL PATCHES FROM THE EASTERN THUMB TO NEAR LAKE ST CLAIR. LATEST RUC...AND TO MUCH LESSER EXTENT NAM...SHOW ENHANCED LOW LEVEL MOISTURE LATE TONIGHT INTO FRIDAY DAYTIME HOURS IN NORTHEAST FLOW OFF OF LAKE HURON...BUT YET NAM AND NGM MOS GUIDANCE BOTH SHOW CLEAR FOR ALL TAF SITES. CHANCE OF MUCH IN WAY OF LAKE EFFECT CLOUDS DEVELOPING AND MOVING INTO TAF SITES APPEARS MARGINAL AT BEST...BUT GIVEN SOME POTENTIAL FOR THIS WILL RETAIN TEMPO GROUP FROM 10Z THROUGH 12Z AT KFNT FOR POSSIBLE CEILINGS NEAR 3K FEET. THERMAL TROUGH STILL HANGING AROUND OVERHEAD OVERNIGHT TO PROMOTE DELTA TS OVER LAKE HURON WELL INTO THE TEENS. LATEST MODEL DATA SHOWS OVERALL VERY LITTLE MOISTURE TO WORK WITH THROUGH FRIDAY EVENING...WITH SURFACE RIDGE SETTLING IN. LATEST NAM LOW THROUGH MID LEVEL QVECTOR AND OMEGA FIELDS CONTINUE TO INDICATE SUBSIDENCE THROUGH THE TAF PERIOD...AND AWIPS CUMULUS SCHEME IS VERY WEAK IN DIURNAL CLOUD DEVELOPMENT POTENTIAL FRIDAY. EXCEPT AS NOTED FOR KFNT ABOVE...06Z TAFS WILL BE VFR...IN FACT NO CEILINGS. NO VISIBILITY RESTRICTIONS EITHER. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...FROST ADVISORY...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055- MIZ060-MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070-MIZ075- MIZ082 UNTIL 9 AM FRIDAY. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...GSS LONG TERM....SF AVIATION...DWD YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 105 AM EDT FRI OCT 6 2006 .AVIATION... SATELLITE IMAGERY VERY LATE IN EVENING SHOWS SOUTHEAST MI NEARLY FREE OF CLOUDS...THE MAIN CLOUDS BEING SMALL PATCHES FROM THE EASTERN THUMB TO NEAR LAKE ST CLAIR. LATEST RUC...AND TO MUCH LESSER EXTENT NAM...SHOW ENHANCED LOW LEVEL MOISTURE LATE TONIGHT INTO FRIDAY DAYTIME HOURS IN NORTHEAST FLOW OFF OF LAKE HURON...BUT YET NAM AND NGM MOS GUIDANCE BOTH SHOW CLEAR FOR ALL TAF SITES. CHANCE OF MUCH IN WAY OF LAKE EFFECT CLOUDS DEVELOPING AND MOVING INTO TAF SITES APPEARS MARGINAL AT BEST...BUT GIVEN SOME POTENTIAL FOR THIS WILL RETAIN TEMPO GROUP FROM 10Z THROUGH 12Z AT KFNT FOR POSSIBLE CEILINGS NEAR 3K FEET. THERMAL TROUGH STILL HANGING AROUND OVERHEAD OVERNIGHT TO PROMOTE DELTA TS OVER LAKE HURON WELL INTO THE TEENS. LATEST MODEL DATA SHOWS OVERALL VERY LITTLE MOISTURE TO WORK WITH THROUGH FRIDAY EVENING...WITH SURFACE RIDGE SETTLING IN. LATEST NAM LOW THROUGH MID LEVEL QVECTOR AND OMEGA FIELDS CONTINUE TO INDICATE SUBSIDENCE THROUGH THE TAF PERIOD...AND AWIPS CUMULUS SCHEME IS VERY WEAK IN DIURNAL CLOUD DEVELOPMENT POTENTIAL FRIDAY. EXCEPT AS NOTED FOR KFNT ABOVE...06Z TAFS WILL BE VFR...IN FACT NO CEILINGS. NO VISIBILITY RESTRICTIONS EITHER. && .PREV DISCUSSION...ISSUED 335 PM EDT THU OCT 5 2006 SHORT TERM...TONIGHT AND FRIDAY LAKE STRATUS COMBINING WITH THE APPROACH OF SHORT WAVE TROUGH AND THE PEAK HEATING HAS RESULTED IN SCT-BKN DECK NORTH OF M59 TODAY. IN FACT...SOME LIGHT RAIN SHOWERS HAVE BEEN OBSERVED VIA RADAR IN SAGINAW BAY INTO ADJACENT HURON AND TUSCOLA COUNTIES SHORELINES. SOME MESOSCALE INFLUENCES ARE OBSERVED IN THE 1KM IMAGERY AS A NORTHEAST COMPONENT TO THE WIND HAS KEPT SKIES MAINLY SUNNY SOUTH OF 8-MILE ROAD DOWN TO THE MICHIGAN STATE LINE. HERE TOO SOME CLOUDS WILL FILL IN AS THIS AFOREMENTIONED TROUGH SWINGS THROUGH THE REGION THIS EVENING. SKIES SHOULD CLEAR OUT THIS EVENING BUT THEN THE COMPLICATED LAKE STRATUS FORECAST DEVELOPMENT OVERNIGHT. ONCE AGAIN...THE WRF-NMM AND RUC2-13KM SUGGEST ANOTHER BAND OF LAKE CLOUDS WILL DEVELOP AND IMPACT BAX-JXN OVERNIGHT. HOWEVER...AS OBSERVED IN THE WATER VAPOR IMAGERY AND UPSTREAM SATELLITE TRENDS OFF LAKE SUPERIOR REVEAL CLOUDS DECREASING DUE TO THE INCREASED SUBSIDENCE. MODEL CONSENSUS FAVORS STRONG SUBSIDENCE OVERNIGHT AS TROUGH AMPLIFIES JUST TO OUR SOUTHEAST. SO AT THE MINIMUM CLR-PTCLOUDY SKIES FOR PORTIONS OF THE THUMB-FNT-OZW WITH MOCLEAR SKIES ELSEWHERE. WITH UPSTREAM DEWPOINTS INTO THE LOWER 30S AND DEWPOINTS ACROSS THE CWA INTO THE MIDDLE 30S...COMBINE THAT WITH SURFACE HIGH PRESSURE TO BUILD ACROSS THE STATE OVERNIGHT...TEMPERATURES SHOULD HAVE NO PROBLEM DIPPING DOWN INTO THE 30S AWAY FROM THE LAKE HURON SHORELINE...LAKE ERIE SHORELINE AND DOWNTOWN DTW (EVEN IF CLOUDS DEVELOP...SHOULD BE ENOUGH BREAKS). THEREFORE FROST ADVISORIES WILL BE HOISTED TONIGHT FOR MOST OF THE CWA. A NICE END TO THE WEEK WITH RIDGE BUILDING AT ALL LEVELS AND A DRY COLUMN TO BRING SUNSHINE. WITH MORE SUNSHINE AND A 2-3 DEGREE RISE AT 850MB...SHOULD RESULT INTO A NICE DIURNAL RISE OF 25-30 DEGREES INTO THE LOWER 60S INLAND...UPPER 50S NEAR LAKE HURON. LONG TERM...FRIDAY NIGHT THROUGH NEXT THURSDAY ANOTHER CHILLY/FROSTY START TO THE DAY IS IN STORE FOR SATURDAY AFTER A CLEAR FRIDAY NIGHT WITH CALM WIND AND CONTINUED IDEAL RADIATIONAL COOLING CONDITIONS. THE 12Z MODELS INDICATED SOME THIN CIRRUS IS POSSIBLE OVER THE AREA FRIDAY NIGHT WITH THE UPPER RIDGE AXIS JUST TO OUR WEST BUT NOT ENOUGH TO AID IN ELEVATING TEMPERATURES. THE GOING FORECAST CALLS FOR AREAS OF FROST IN MOST LOCATIONS AWAY FROM THE LAKES AND CITY OF DETROIT AND THIS LOOKS GOOD WITH LOW TEMPS AS CHILLY AS 32F POSSIBLE IN THE TYPICALLY COLDER LOCATIONS OF THE INTERIOR THUMB AND CENTRAL LOWER. THE WEEKEND WARMING TREND WILL THEN GET UNDERWAY DURING SATURDAY AFTERNOON. THE SURFACE RIDGE WILL SLIDE TO OUR EAST AND ALLOW SOUTHERLY RETURN FLOW TO BEGIN. MODEL FORECAST SOUNDINGS SHOW A MODEST MIXED BOUNDARY LAYER GENERALLY BELOW 900 MB. THIS IS ABOUT RIGHT FOR EARLY OCTOBER IN A STRONG LOW LEVEL WARM ADVECTION PATTERN. THE RESULT WILL BE HIGH TEMPS LOWER THAN THE POTENTIAL INDICATED BY WARMING 850 MB TEMPS BUT ON THE HIGH SIDE OF THE MACHINE NUMBERS WHEN FACTORING IN PLENTIFUL SUNSHINE. HIGHS WILL BE AT LEAST IN THE MID 60S AND WILL LIKELY TOUCH 70 IN THE SAGINAW VALLEY WITH STRONGER SW FLOW. THE SW FLOW WILL BE STRONGER BUT THE GRADIENT IN THE MODELS DOES NOT LOOK LIKE ENOUGH TO MAINTAIN A STEADY WIND SATURDAY NIGHT, ESPECIALLY SOUTH OF INTERSTATE 69. PLAN TO SHADE LOW TEMPS ON THE COOL SIDE OF GUIDANCE WITH THE EXPECTATION OF GREATER RADIATIONAL COOLING POTENTIAL. WITH ONLY THIN CIRRUS EXPECTED ONCE AGAIN, PREFER THE COOLER MET/NAM TEMPERATURE GUIDANCE WITH OFFERINGS DOWN NEAR 40. SUNDAY WILL BE VERY SIMILAR TO SATURDAY IN TERMS OF THE TEMPERATURE PROFILE AND SKY CONDITION, EXCEPT THE ENTIRE ATMOSPHERE WILL BE A FEW DEGREES WARMER THANKS TO EVEN STRONGER SW LOW LEVEL FLOW. THIS WILL BE DUE TO A RESPECTABLE LOW PRESSURE SYSTEM TAKING SHAPE IN CENTRAL CANADA, WHICH THE 12Z MODELS MAINTAIN ON THE STRONG SIDE AND CENTERED NEAR JAMES BAY BY SUNDAY AFTERNOON. HIGHS IN THE LOWER TO MID 70S WILL BE REACHABLE AHEAD OF THE ASSOCIATED COLD FRONT THAT WILL BE ON OUR DOORSTEP BY SUNDAY EVENING. TIMING ON THE PASSAGE OF THIS FRONT REMAINS CONSISTENT IN THE MODELS FOR SUNDAY NIGHT BUT WITH A LIMITED MOISTURE SUPPLY, SO MUCH SO THAT THE NORMALLY GENEROUS GFS OFFERS ONLY A FEW 100THS INCH QPF SUNDAY NIGHT AND MONDAY. MORE CERTAIN THAN RAIN CHANCES IS ANOTHER PUSH OF COLD AIR THAT WILL TAKE TEMPERATURES DOWN TO THE RANGE COMPARABLE TO EARLIER THIS WEEK WITH HIGHS IN THE UPPER 50S TO LOWER 60S AND THE USUAL COMPLEMENT OF COLD AIR STRATOCU ON MONDAY. CONSIDERING THE CONSISTENT TIMING ON THE SUNDAY NIGHT/MONDAY FRONTAL SYSTEM, CONFIDENCE IS MODERATE THAT HIGH PRESSURE WILL BE IN PLACE OVER SE MICHIGAN BY TUESDAY AS THE WHEELS TURN ON ANOTHER SUBSTANTIAL UPPER AIR PATTERN CHANGE. ADVERTISEMENT OF THIS BEGAN IN LAST NIGHTS MODEL RUNS AND CONTINUED TODAY. THE DRIVER OF THE CHANGE WILL BE STRONG AMPLIFICATION IN THE UPPER AIR PATTERN OVER THE EASTERN PACIFIC LEADING TO DOWNSTREAM DEVELOPMENT OF A LARGE CLOSED UPPER LOW DURING THE WEDNESDAY AND THURSDAY PERIOD. TRENDS IN THE 12Z RUN OF THE GFS SHOW AN UPPER AIR PATTERN THAT IS NOT AS DEEP/COLD AS THE PREVIOUS COUPLE OF RUNS, BUT WITH SIMILAR TIMING ON THE EVOLUTION OF THE SYSTEM. DETAILS ON THE SURFACE FEATURES WILL BE REFINED WITH TIME BUT THE BEST SHOT RIGHT NOW BRINGS THE COLD FRONT AND A CHANCE OF SHOWERS INTO THE AREA WEDNESDAY NIGHT AND THURSDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...FROST ADVISORY...MIZ047-MIZ048-MIZ049-MIZ053-MIZ054-MIZ055- MIZ060-MIZ061-MIZ062-MIZ063-MIZ068-MIZ069-MIZ070-MIZ075- MIZ082...MIDNIGHT FRIDAY TO 9 AM FRIDAY. LAKE HURON...NONE. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION...DWD SHORT TERM...BGM LONG TERM....BT YOU CAN OBTAIN YOUR LATEST NATIONAL WEATHER SERVICE FORECASTS ONLINE AT WWW.WEATHER.GOV/DETROIT (ALL LOWER CASE). mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BINGHAMTON NY 922 AM EDT FRI OCT 6 2006 .SHORT TERM /REST OF TODAY/... UPDATED ZONES TO REMOVE MORNING HEADLINE FOR FROST ADV. SATELLITE SHOWS MID/HIGH CLOUDS ACROSS MUCH OF CWA FROM I81 EAST IN NYS AND ALL OF NE PA. SATELLITE TRENDS AND RUC/GFS MOISTURE PROGS INDICATE FAIRLY DENSE MID/HIGH LEVEL MOISTURE WILL PERSIST THROUGH THIS AFTERNOON ESP ACROSS WYOMING VALLEY/POCONOS. UPDATED GRIDS/ZONES TO MOSTLY CLOUDY HERE AND MOSTLY SUNNY FINGER LAKES AND NRN ZONES WITH PS IN BETWEEN. NO OTHER CHANGES. && .PREV DISCUSSION... /ISSUED 805 AM EDT FRI OCT 6 2006/ SHORT TERM /TODAY THROUGH SATURDAY NIGHT/... HIPRES OVER THE ST LAWRENCE VLY HOLDING THE CLSD LOW AND RAIN SOUTH OF THE FCST AREA. HWVR...CLDS FROM THE SYSTEM HAS HELPED KEEP TEMPS FROM FALLING TOO SHARPLY SO FAR. MOST CRNTS NEAR OR ABV 40. VERY DRY AIR WILL ALLOW FOR CNSRBL SUN TODAY...ALTHOUGH SOME CI MAY HANG ARND THE CNTRL AND SRN ZONES FOR PART OF THE MRNG. SOME LAKE EFFECT STREAMERS SHOWN OF ERIE AND ONTARIO...BUT NE FLOW WILL KEEP THEM OUT OF THE FCST AREA. TNGT WILL BE COLDER THAN LAST WITH FEW OR NO CLDS AVBL TO LIMIT THE RADIATION. NE FLOW WILL LIMIT LAKE MODIFICATION OF THE AIR...SO BELIEVE TEMPS WILL DROP INTO THE LWR 30S...AND EVEN SOME UPPER 20S. HAVE ONCE AGAIN ISSUED FROST ADVISORIES FOR MUCH OF THE AREA...WITH FREEZE WARNING ACROSS THE SRN TIER AND CATSKILLS...AWAY FROM THE LAKES INFLUENCE. DRY CONDS CONT FOR THE REMAINDER OF THE PD. FLWD BLENDED MOS GUID FOR TEMPS. AVIATION... CLDS ACRS SE SXNS WITH VFR CIGS 5-6K FT AT AVP. LOWER DECK SHUD PULL OUT WITH JUST AN AC OR CI DECK BY THIS AFTN. OTRW, VFR CONDITIONS WITH ONLY SCT CLD. WINDS GNRLY NE 10 KTS OR LESS. LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... GFS MOS TEMPS APPEAR SEVERAL DEG TOO HIGH FOR SATURDAY NIGHT/EARLY SUNDAY IN THE PRESENCE OF LIGHT WIND AND DRY AIR UNDER THE CENTER OF HIGH PRESSURE. TEMPS MAY EVEN HAVE TO ADJUSTED FURTHER DOWNWARD A FEW MORE DEG WITH THE POTENTIAL FOR FROST/FREEZING CONDITIONS. A WEAK COOL FRONT WILL CROSS THE REGION MONDAY...BUT LIKELY ACCOMPANIED BY NOTHING MORE THAN SOME CLOUDS AD PERHAPS A FEW SPRINKLES. UPPER HEIGHTS SLOWLY DROP AS THE FLOW ALOFT BECOMES MORE ZONAL EARLY NEXT WEEK...BEFORE BACKING TO THE SW DURING THE MID TO LATE WEEK. TEMPS WILL TREND BACK TO SLIGHTLY BELOW NORMAL /IN THE 50S/ FOR TUESDAY AND WEDNESDAY...BEFORE REBOUNDING BACK INTO THE 60S LATE IN THE WEEK. && .BGM WATCHES/WARNINGS/ADVISORIES... NY...FREEZE WARNING FOR NYZ022-024-044>046-055>057 FROM 1 AM SATURDAY TO 8 AM SATURDAY. ...FROST ADVISORY FOR NYZ009-015>018-023-025-036-037-062 FROM 1 AM SATURDAY TO 8 AM SATURDAY. PA...FROST ADVISORY FOR PAZ038>040-043 FROM 1 AM SATURDAY TO 8 AM SATURDAY. && $$ SHORT TERM...RRM ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 930 AM EDT FRI OCT 6 2006 .SHORT TERM /THIS AFTERNOON/...PLAN TO UPDATE AND ADD IN CHANCE OF THUNDER ENTIRE FORECAST AREA. WE'RE FORECAST TO REMAIN IN THE WARM SECTOR WITH THE FRONTAL BOUNDARY TO OUR WEST AND NORTH. LATEST RUC40 AND SHORT-RANGE ENSEMBLE PRODUCTS SHOW GOOD INSTABILITY THIS AFTERNOON. LIKELY POPS AND FORECAST TEMPS STILL LOOK GOOD. ALSO ADDED THUNDER TO COASTAL WATERS OVERNIGHT AS INSTABILITY WILL CONTINUE OVERNIGHT ACROSS THE WARM ATLANTIC WATERS. NO CHANGES MADE BEYOND THAT. && .AVIATION...CIG/VIS IMPROVING ACROSS THE FCST AREA. VARYING CIGS/VSBY CATEGORIES EXPECTED TODAY WITH SFC LOW OVER THE AREA AND SOME WEAK ISENTROPIC LIFT DEVELOPING. PRECIP NOT EXPECTED TO OCCUR UNTIL THE AFTERNOON AND EVENING HOURS. SHOULD SEE WIDESPREAD IFR CONDITIONS DEVELOP DURING THE EVENING AND OVERNIGHT HOURS. A PROLONGED PERIOD OF LOW CIGS/VSBYS ARE POSSIBLE THROUGH SUNDAY NIGHT AS NORTHEAST LOW LEVEL FLOW CONTINUES OVER THE AREA. && .MARINE...MODELS COMING INTO BETTER AGREEMENT...AND WILL LEAN TOWARD THE GFS SOLUTION. WILL MAKE A FEW CHANGES TO THE FIRST PERIOD FCST AS ARE EXPECTED TO INCREASE WITH DEVELOPMENT OF SFC LOW OVER THE REGION. REMAINDER OF FCST REMAINS ON TRACK. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 PM THIS AFTERNOON TO 8 AM EDT SATURDAY FOR AMZ150. && $$ HSA/RAP nc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1050 AM EDT FRI OCT 6 2006 .UPDATE /THIS AFTERNOON/... IF THIS WAS ONLY WINTER WITH THIS CURRENT WEATHER SETUP, WE WOULD BE DEALING WITH SNOW! ANYHOW, WATER VAPOR IMAGERY SHOWING A VERY IMPRESSIVE UPPER-LEVEL TROUGH DIGGING SOUTHWARD TO OUR WEST. AN UPPER AIR ANALYSIS SHOWS A STRONG UPPER JET ENTRANCE REGION LOCATED NEAR SOUTHEASTERN PENNSYLVANIA THIS MORNING AND THIS FEATURE WILL PROBABLY NOT MOVE TO MUCH AS THE SHARP TROUGH SETTLES SOUTHWARD THROUGH TODAY AND CLOSES OFF INTO AN UPPER LOW TOWARD THE CENTRAL APPALACHIAN REGION. STRONG LIFT WILL BE MAINLY FOCUSED ACROSS THE SOUTHEASTERN ZONES AND DELMARVA. THE NORTHWESTERN EDGE OF THE STEADY RAIN AS BEEN SLIDING SOUTHEASTWARD THIS MORNING, AND THIS TREND IS DEPICTED TO CONTINUE GRADUALLY THIS AFTERNOON BY THE RUC. THE GOING FORECAST HANDLES THIS TREND WELL AND ONLY SOME MINOR ADJUSTMENTS WERE MADE TO THE TIMING. RAINFALL AMOUNTS HAVE BEEN HEAVIEST ACROSS THE SOUTHERN ZONES WHERE GENERALLY 1 TO 2 INCHES HAS ALREADY FALLEN THROUGH 14Z. ANOTHER INCH OR SO IS QUITE POSSIBLE ACROSS OUR SOUTHERN ZONES, WITH MUCH LESSER AMOUNTS AS YOU GO NORTHWARD. WIDESPREAD FLOODING IS NOT ANTICIPATED, HOWEVER SOME FLOODING OF POOR DRAINAGE AREAS AS WELL AS SOME PONDING OF WATER ON ROADS IS QUITE POSSIBLE. WE WILL MONITOR RAINFALL AMOUNTS AND TRENDS. REGARDING WINDS...THE PRESSURE GRADIENT CONTINUES TO TIGHTEN UP AS LOW PRESSURE ORGANIZES TO OUR SOUTH. THE SURFACE LOW IS NOT FORECAST TO BE THAT STRONG, HOWEVER IT WILL COMBINE WITH A 1036 MB HIGH TO OUR NORTH. THIS WILL BE PLENTY TO CREATE/SUSTAIN A STRONG ONSHORE FLOW. THIS INCREASED NORTHEASTERLY FLOW IS ALREADY BEING OBSERVED AS BUOY 44009 HAS GUSTED TO 45 MPH ALREADY. SOME COASTAL OBSERVING SITES SHOWING GUSTS TO 48 MPH IN AVALON, NJ, 44 MPH AT LEWES, DE AND 33 MPH AT THE ATLANTIC CITY MARINA. THE GOING WIND ADVISORY LOOKS GOOD, HOWEVER WE WILL START IT NOW BASED ON SOME CURRENT WIND GUSTS BEING OBSERVED AT THE COAST AS WELL AS INCREASED THE WIND GUSTS A BIT MORE IN THE FORECAST. TEMPERATURES HAVE BEEN LOWERED A COUPLE OF DEGREES FOR MOST OF THE REGION BASED ON PERSISTENT CLOUD COVER ACROSS THE BOARD AND CONTINUED RAIN FOR THE CENTRAL AND SOUTHERN ZONES. UPDATED PRODUCTS SHOULD HIT THE STREET BY 11:30 AM. ANOTHER UPDATE MAY BE ISSUED BY EARLY AFTERNOON IF ANY HEADLINES CHANGE. && .MARINE... THE COASTAL WATERS FORECAST WAS UPDATED EARLIER TO BEGIN THE GALE WARNINGS A BIT SOONER. THE GALE WARNINGS WILL CONTINUE FOR ALL MARINE ZONES DUE TO A STRONG NORTHEASTERLY FLOW. PEAK WIND GUSTS SHOULD TOP OUT BETWEEN 40 AND 45 KNOTS, WITH THE HIGHER OF THE GUSTS BEING OBSERVED OVER THE OCEAN ZONES. SEAS AT BUOY 44009 ARE UP TO 10 FEET AT 13Z. THE SEAS ARE EXPECTED TO BUILD SOME MORE THROUGH THIS AFTERNOON. && .TIDES... WE CONTINUE TO LOOK AT NEW DATA AND GUIDANCE THIS MORNING REGARDING THE COASTAL FLOOD POTENTIAL. WE ARE LOOKING INTO THE POSSIBILITY OF UPGRADING THE COASTAL FLOOD WATCH TO A WARNING OVER THE NEXT COUPLE OF HOURS. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...WIND ADVISORY FOR NJZ024-025 UNTIL 10 AM SATURDAY. ...COASTAL FLOOD WATCH FOR NJZ012>014-016-020>027 FROM 7 PM FRIDAY TO 2 AM SUNDAY. DE...COASTAL FLOOD WATCH FOR DEZ001>004 FROM 7 PM FRIDAY TO 2 AM SUNDAY. ...WIND ADVISORY FOR DEZ004 UNTIL 10 AM SATURDAY. MD...NONE. MARINE...GALE WARNING FOR ANZ430-431-450>455 UNTIL NOON SATURDAY. && $$ UPDATE...GORSE MARINE/TIDES...O'HARA pa AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 1118 AM EDT FRI OCT 6 2006 .SHORT TERM /REST OF TODAY/... LARGE AREA OF RAIN EXITED THE EASTERN COUNTY WARNING AREA BY 12Z WITH ONLY SCATTERED LIGHT RAIN FROM EASTERN WEST VIRIGNIA INTO SOUTH CENTRAL VIRGINIA AT 15Z. PRECIPITATION IS ORIENTED AROUND UPPER LOW NOW CENTERED IN EASTERN WEST VIRGINIA. LATEST RUC MODELS BRING UPPER LOW INTO THE MIDDLE OF THE COUNTY WARNING AREA BY 00Z TONIGHT. AS STEERING WINDS AROUND THE LOW BECOME MORE EAST AND NORTHEAST BETWEEN 18-21Z A MORE WIDEPSREAD AREA OF RAIN WILL SPREAD ACROSS THE FORECAST AREA. TEMPERATURES WILL ALSO DROP ALOFT WHICH SHOULD ENHANCE THE CLOUD COVER AND KEEP THE FORECSAT AREA STABLE ENOUGH TO PRVENT ANY THUNDER. SURFACE LOW IS NOW MOVING INTO EASTERN NORTH CAROLINA. SURFACE WINDS WILL INCREASE FROM THE NORTH AND NORTHEAST ALLOWING A BETTER SURGE OF COLD AIR ARRIVING BY LATE AFTERNOON. GUIDANCE AT ALL FORECAST SITES HAD TEMPERATURES DROPPING THIS AFTERNOON. THIS WILL BE REFLECTED IN THE GRIDDED DATABASE...ESPECIALLY IN THE NORTHEAST COUNTY WARNING AREA WHERE THE BEST COVERAGE OF RAIN WILL BE THIS AFTERNOON. && .PREV DISCUSSION... (ISSUED 643 AM EDT FRI OCT 6 2006) AVIATION... STRONG NE WINDS ALOFT WILL DEVELOP TODAY AS LOW PRES DEVELOPS ON THE COAST. 30 TO 40 KT WINDS CAN BE EXPECTED ABOVE ABOUT 1500 FEET BY AFTN. SOME OF THIS WIND WILL TRANSLATE TO THE SFC AND THINK INCREASE IN WIND SPEEDS FROM THE SFC TO 1500 WILL BE GRADUAL ENUF TO PRECLUDE LLWS AT DAN/LYH/ROA. LEFT LLWS IN LWB AND BLF FOR LATE TDA AND TNGT AS SFC WINDS LIKELY TO BECOME LIGHT. THESE WINDS ALOFT CONTINUE THRU 12Z SAT. LOOK FOR SOME IMPROVEMENT IN CIGS TODAY BUT NOT MUCH. MVFR IS PROBABLY AS GOOD AS IT GETS TODAY WITH ABUNDANT LOW LEVEL MOISTR IN PLACE FOR A WHILE. SFC WINDS FROM THE NE MAY KEEP VSBYS IN GOOD SHAPE FOR THE FIRST PART OF THE DAY...BUT THEN CHC OF RAIN INCREASES AND THUS LOWER (MVFR) VSBYS. RAIN CONTS TNGT WITH SLOWLY LOWERING CIGS AND VSBYS. PREV DISCUSSION... (ISSUED 259 AM EDT FRI OCT 6 2006) SHORT TERM /REST OF TODAY THROUGH MONDAY/... STRONG SHORTWAVE DIVING DOWN THRU THE OHIO VALLEY AND RESULTANT INCREASING DIVERGENCE OVER THE REGION PRODUCING WIDESPREAD RAINFALL COVERAGE. MEANWHILE COLD FRONT STALLED OVER THE SOUTHERN PORTIONS OF THE FCST AREA (FA) HAVING A HARD TIME PUSHING SOUTH THANKS TO ADVANCING UPPER WAVE AND STRENGTHENING SFC LOW NEAR CLT. THIS LOW WILL MOVE TO THE COAST TODAY WITH INCREASING NORTHERLY FLOW IN ITS WAKE REALLY PULLING DOWN THE COOL AIR. HIGH TEMPS WILL LIKELY BE EARLY THIS MORNING WITH FALLING TEMPS THE REST OF THE DAY. MEANWHILE RAIN SHIELD WILL SLOWLY MOVE EAST THIS MORNING...THEN AS UPPER WAVE CLOSES OFF OVER NC RAIN WILL WRAP BACK AROUND INTO THE MTNS AND PERSIST INTO THE OVERNIGHT PD TNGT. STRONG PRESSURE GRADIENT BETWEEN THE COASTAL LOW AND HIGH PRES OVER NEW ENGLAND WILL KEEP IMPRESSIVE LOW LVL NE FLOW AND VERY CHILLY TEMPS ACROSS THE FA THRU SATURDAY. SYSTEM BECOMES VERTICALLY STACKED BY SATURDAY RESULTING IN DECREASING DYNAMIC SPPT FOR RAINFALL. AREAS OF RAIN LIKELY TO ARND SATURDAY BUT MUCH MORE WIDELY SCTD. MODELS IN GOOD AGREEMENT ON THE UPR LOW DRIFTING SOUTH THRU THE WEEKEND WITH GRADUALLY IMPROVING CONDITIONS THROUGH MONDAY AS SFC HIGH PRESSURE PUSHES DOWN INTO THE MID-ATLANTIC REGION. PREV DISCUSSION... (ISSUED 845 PM EDT THU OCT 5 2006) SHORT TERM /REST OF TONIGHT/... EVENING TSTMS HAVE WEEKENED. HOWEVER...ANTICIPATE WIDESPREAD SHOWERS WITH EMBEDDED THUNDER DURING THE OVERNIGHT AS UPPER FLOW TRANSFORMS INTO HIGH AMPLITUED CONFIGURATION WITH BOOKEND CUTOFF LOWS ON EITHER SIDE OF THE MID CONUS RIDGE COME THIS TIME FRIDAY. SIGNIFICANT DINAMIC LIFT IF FCST OVER THE MID ATLANTIC THE NEXT 24 HOURS...THUS SO ANTICIPATING WET CONDITIONS TO PERSIST WITH 1-2 INCHES QPF THROUGH 00 UTC TOMORROW EVENING. A LITTLE CONCERNED ABOUT OVERALL QPF POTENTIAL. PWATS HAVE CLIMBED WELL ABOVE 1 INCH AT RNK/GSO...THE GSO SOUNDING A VERY MOIST 1.50. IF MODELS ARE CORRECT WITH DEEP EASTERLY FLOW SETTING UP EARLY FRIDAY...UPSLOPE FLOW AND SLOW CELL MOTION IN COMBINATION WITH THIS HIGH PWAT AIRMASS COULD EASIALLY SUPPORT RAIN RATES THAT WOULD RESULT IN MORE THAN 1-2 INCHES OF QPF. IF THIS OCCURS...MAY NEED TO CONSIDER FLOOD WATCH FOR SOME AREAS ALONG AND EAST OF THE BLUE RIDGE...IN SPITE OF THE LOW STREAM LEVELS. AVIATION... CIGS WILL GRADUALLY LOWER OVERNIGHT WITH WIDESPREAD AREAS OF RAIN WITH EMBEDDED TSRA. ANTICIPATE WIDESPREAD IFR CONDITIONS AFT 06 UTC...CONDITIONS PERSISTING THROUGH THE PD. PREV DISCUSSION... (ISSUED 351 PM EDT THU OCT 5 2006) SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... MAIN CONCERN CONTINUES TO BE UPR LOW THAT WILL BE INFLUENCING THE LOCAL WX THRU THE SHORT TERM. LATE MORNING ANALYSIS SHOWED CONTINUED AMPLIFICATION OF UPR RIDGE ACRS THE CENTRAL CONUS...ALLOWING PIECE OF ENERGY DROPPING THRU THE GREAT LAKES THIS AFTN TO BEGIN DIGGING SHARPLY SOUTHWARD PER LATEST WV PICS. AT THE SFC...BACKDOOR FRONT MAKING GOOD PROGRESS SOUTHWARD EAST OF THE MOUNTAINS...WITH DRIER AIR BEGINNING TO FILTER SOUTH THRU NORTHERN VA. LOW LEVEL WINDS BACK TO THE SOUTHWEST TONIGHT AHEAD OF THE COLD FRONT. MSAS AND SPC ANALYSIS HAS BEST LIFT AND INSTABILITY ALONG THE SOUTHERN BLUE RIDGE INTO THE NORTH CAROLINA FOOTHILLS. LOW LEVEL CONVERGENCE IS MAXIMIZED IN THIS AREA AND RADAR IS ALREADY SHOWING THUNDERSTORMS DEVELOPING IN TAZEWELL...CARROL AND PATRICK COUNTIES. COVERAGE WILL BE BEST IN THE FOOTHILLS WITH ONLY SCATTERED SHOWERS FOR THE REST OF THE FORECAST AREA. WILL HAVE HIGHEST CHANCE OF RAIN IN THE SOUTHWEST COUNTY WARNING AREA THIS EVENING. BIG TRANSITION IN THE UPPER PATTERN TONIGHT AS SHORT WAVE OVER THE UPPER MISSISSIPPI VALLEY DIVES SOUTHEAST AND CLOSES OFF OVERNIGHT. BEST SYNOPTIC SCALE LIFT ARRIVES AFTER 03Z AND BY 06Z FORECAST AREA IN UNDER AN AREA OF STRONG UPPER DIFFLUENCE BETWEEN COUPLED JETS AND STRONG ISENTROPIC LIFT AROUND THE 300K LAYER. PRECIPITATBLE WATER VALUES HAVE BEEN CLIMBING FOR THE LAST FEW DAYS AND ARE NOW GREATER THAN 1.0 INCH. AT THE SURFACE THE PRIMARY LOW MOVES FROM THE TENNESSEE VALLEY INTO THE CAROLINAS BY FRIDAY MORNING. IN ADDITION...TONIGHT WILL BE THE START OF A BIG SURGE OF COLDER TEMPERATURES INTO THE AREA WITH 850 MB WINDS BECOMING NORTHEAST AND 850 MB TEMPERATURES DROPPING DOWN TO AROUND +6 IN THE NORTHWEST COUNTY WARNING AREA BY 12Z. SO PLAN TO INCREASE CHANCE OF RAIN ESPECIALLY IN THE 03-09Z TIME FRAME. RAISED MINIMUM TEMPERATURES IN THE EAST TONIGHT...CLOSER TO MAV GUIDANCE. MODEL GUIDANCE STILL IN GOOD AGREEMENT IN DROPPING CLOSED UPR SYSTEM SOUTH ACRS THE REGION THRU EARLY SATURDAY BEFORE FINALLY PUSHING TO THE SOUTHEAST COAST BY SUNDAY. THIS SHOULD MEAN AN EXTENDED PERIOD OF MAINLY CLOUDY AND COOL CONDITIONS...ALONG WITH OCCASIONAL RAIN CHANCES. BEST PRECIP CHANCES AFTER TONIGHT STILL APPEAR TO RESIDE OVER THE EASTERN HALF OF THE CWA IN CLOSEST PROXIMITY TO BEST FORCING INITIALLY...AND THEN IN AREA OF BETTER WARM ADVECTION WRAP AROUND PRECIP BY SATURDAY AS UPR LOW SINKS SOUTH. STILL HAVE QUESTIONS ABOUT SFC LOW DEVELOPMENT OFF THE COAST FRIDAY INTO SATURDAY. THINKING MODELS MAY BE UNDERDOING DEVELOPMENT GIVEN SUCH A STRONG SYSTEM ALOFT AND INCREASED BAROCLINICITY ALONG THE COAST. WILL RUN WITH THE IDEA OF A STRONGER SFC SYSTEM...WHICH IN CONTRAST TO STRONG SFC HIGH TO THE NORTH IS LIKELY TO CREATE SOME RATHER GUSTY WINDS ACRS THE PIEDMONT FRIDAY AFTN INTO FRIDAY NIGHT. TEMPS ON FRIDAY LIKELY TO GO NOWHERE (BUT DOWN IN THE AFTN) WITH STRONG COLD ADVECTION...CLOUDS...AND LIKELY OCCASIONAL RAIN. HIGHS TO COME EARLY FOR MANY AREAS AND HAVE FOLLOWED MAV MOS GUIDANCE WHICH LOOKS REASONABLE IN THIS SITUATION. OTHERWISE CONTINUED CLOUDY AND COOL FOR SATURDAY WITH PRECIP LINGERING OVR THE EAST. SYSTEM FINALLY LOOKS TO GIVE UP ITS INFLUENCE ON THE LOCAL WX BY SUNDAY ALTHOUGH DEEP EASTERLY FLOW MAY BE ENOUGH TO HOLD SOME LOWER CLOUDS AND COOLER TEMPS IN PLACE. LONG TERM /MONDAY THROUGH THURSDAY/... OVERALL PATTERN WILL BEGIN TO AMPLIFY MONDAY AS STUBBORN UPR LOW BEGINS TO FILL AND GETS SHUNTED FARTHER EAST GIVEN APPROACHING UPSTREAM SHORTWAVE TROUGH. THIS WILL ALLOW FOR A WARMER DAY ON MONDAY AS STRONG RIDGING ALOFT TO THE WEST FINALLY FOLDS OVER INTO THE REGION. PREVIOUSLY MENTIONED TROUGH APPROACHING ON LATE MONDAY/EARLY TUESDAY WILL DRIVE A WEAK COLD FRONT ACRS THE REGION EARLY IN THE DAY...BUT WITH LITTLE TO NO MOISTURE TO WORK WITH GIVEN RIDGING ACRS THE GULF...WILL HOLD ONTO A DRY FCST. PATTERN THEN BEGINS TO ONCE AGAIN UNDERGO SIGNIFICANT CHANGES BY THE LATTER HALF OF THE PERIOD...AS STRONG RIDGING DEVELOPING INTO THE GULF OF ALASKA HELPS CARVE OUT DEEPENING UPR TROUGH ACRS THE CENTRAL CONUS. WHILE SPECIFICS ON THE TIMING AND DEGREE OF TROUGHING CERTAINLY FAR FROM SET IN STONE...OVERALL PATTERN WOULD SUGGEST ONE OF BUILDING HEIGHTS ACRS THE AREA ON WEDNESDAY FOLLOWED BY A TRANSITION TO DEEP SOUTHWEST FLOW ALOFT BY THURSDAY. NOT YET READY TO ACCEPT THE EXTREMELY DEEP SYSTEM OVR THE NORTHERN PLAINS SUGGESTED BY THE GFS...BUT OTHER GLOBAL MODELS AND ENSEMBLE MEMBERS SUGGEST A LIKELIHOOD OF PRECIP BY THE END OF THE EXTENDED PERIOD. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ AMS va AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1253 PM EDT FRI OCT 6 2006 .UPDATE #2... A QUICK TEXT PRODUCT UPDATE WILL BE SENT SHORTLY TO CHANGE A HEADLINE, AS WE JUST UPGRADED THE COASTAL FLOOD WATCH TO A WARNING. && .UPDATE#1 /THIS AFTERNOON/... IF THIS WAS ONLY WINTER WITH THIS CURRENT WEATHER SETUP, WE WOULD BE DEALING WITH SNOW! ANYHOW, WATER VAPOR IMAGERY SHOWING A VERY IMPRESSIVE UPPER-LEVEL TROUGH DIGGING SOUTHWARD TO OUR WEST. AN UPPER AIR ANALYSIS SHOWS A STRONG UPPER JET ENTRANCE REGION LOCATED NEAR SOUTHEASTERN PENNSYLVANIA THIS MORNING AND THIS FEATURE WILL PROBABLY NOT MOVE TO MUCH AS THE SHARP TROUGH SETTLES SOUTHWARD THROUGH TODAY AND CLOSES OFF INTO AN UPPER LOW TOWARD THE CENTRAL APPALACHIAN REGION. STRONG LIFT WILL BE MAINLY FOCUSED ACROSS THE SOUTHEASTERN ZONES AND DELMARVA. THE NORTHWESTERN EDGE OF THE STEADY RAIN AS BEEN SLIDING SOUTHEASTWARD THIS MORNING, AND THIS TREND IS DEPICTED TO CONTINUE GRADUALLY THIS AFTERNOON BY THE RUC. THE GOING FORECAST HANDLES THIS TREND WELL AND ONLY SOME MINOR ADJUSTMENTS WERE MADE TO THE TIMING. RAINFALL AMOUNTS HAVE BEEN HEAVIEST ACROSS THE SOUTHERN ZONES WHERE GENERALLY 1 TO 2 INCHES HAS ALREADY FALLEN THROUGH 14Z. ANOTHER INCH OR SO IS QUITE POSSIBLE ACROSS OUR SOUTHERN ZONES, WITH MUCH LESSER AMOUNTS AS YOU GO NORTHWARD. WIDESPREAD FLOODING IS NOT ANTICIPATED, HOWEVER SOME FLOODING OF POOR DRAINAGE AREAS AS WELL AS SOME PONDING OF WATER ON ROADS IS QUITE POSSIBLE. WE WILL MONITOR RAINFALL AMOUNTS AND TRENDS. REGARDING WINDS...THE PRESSURE GRADIENT CONTINUES TO TIGHTEN UP AS LOW PRESSURE ORGANIZES TO OUR SOUTH. THE SURFACE LOW IS NOT FORECAST TO BE THAT STRONG, HOWEVER IT WILL COMBINE WITH A 1036 MB HIGH TO OUR NORTH. THIS WILL BE PLENTY TO CREATE/SUSTAIN A STRONG ONSHORE FLOW. THIS INCREASED NORTHEASTERLY FLOW IS ALREADY BEING OBSERVED AS BUOY 44009 HAS GUSTED TO 45 MPH ALREADY. SOME COASTAL OBSERVING SITES SHOWING GUSTS TO 48 MPH IN AVALON, NJ, 44 MPH AT LEWES, DE AND 33 MPH AT THE ATLANTIC CITY MARINA. THE GOING WIND ADVISORY LOOKS GOOD, HOWEVER WE WILL START IT NOW BASED ON SOME CURRENT WIND GUSTS BEING OBSERVED AT THE COAST AS WELL AS INCREASED THE WIND GUSTS A BIT MORE IN THE FORECAST. TEMPERATURES HAVE BEEN LOWERED A COUPLE OF DEGREES FOR MOST OF THE REGION BASED ON PERSISTENT CLOUD COVER ACROSS THE BOARD AND CONTINUED RAIN FOR THE CENTRAL AND SOUTHERN ZONES. UPDATED PRODUCTS SHOULD HIT THE STREET BY 11:30 AM. ANOTHER UPDATE MAY BE ISSUED BY EARLY AFTERNOON IF ANY HEADLINES CHANGE. && .MARINE... THE COASTAL WATERS FORECAST WAS UPDATED EARLIER TO BEGIN THE GALE WARNINGS A BIT SOONER. THE GALE WARNINGS WILL CONTINUE FOR ALL MARINE ZONES DUE TO A STRONG NORTHEASTERLY FLOW. PEAK WIND GUSTS SHOULD TOP OUT BETWEEN 40 AND 45 KNOTS, WITH THE HIGHER OF THE GUSTS BEING OBSERVED OVER THE OCEAN ZONES. SEAS AT BUOY 44009 ARE UP TO 10 FEET AT 13Z. THE SEAS ARE EXPECTED TO BUILD SOME MORE THROUGH THIS AFTERNOON. && .TIDES... THE COASTAL FLOOD WATCH HAS BEEN UPGRADED TO A WARNING. THE LATEST INFORMATION CAN BE OBTAINED IN THE PRODUCT, PHLCFWPHI. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...NONE. NJ...WIND ADVISORY FOR NJZ024-025 UNTIL 10 AM SATURDAY. ...COASTAL FLOOD WARNING FOR NJZ012>014-016-020>027 FROM 7 PM FRIDAY TO 2 AM SUNDAY. DE...COASTAL FLOOD WARNING FOR DEZ001>004 FROM 7 PM FRIDAY TO 2 AM SUNDAY. ...WIND ADVISORY FOR DEZ004 UNTIL 10 AM SATURDAY. MD...NONE. MARINE...GALE WARNING FOR ANZ430-431-450>455 UNTIL NOON SATURDAY. && $$ UPDATES...GORSE MARINE/TIDES...O'HARA pa AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 149 PM EDT FRI OCT 6 2006 .AVIATION... CEILINGS WILL BE IFR OR LOWERING TO IFR BY 03Z TONIGHT AS DEEPENING UPPER LOW MOVES ACROSS THE FORECAST AREA. WINDS THROUGH A DEEP LAYER WILL HAVE AN EASTERLY COMPONENT WHICH WILL AIDE IN LIFT FOR WIDESPREAD PRECIPITAION TONIGHT AND RESULT IN BANKING THE STRATUS UP AGAINST THE EAST SIDE OF THE BLUE RIDGE. AS THE UPPER LOW MOVES SOUTH ON SATURDAY RAIN WILL GRADUALLY MOVE OUT OF THE AREA AND VISIBILITES WILL IMPROVE. WINDS AT 1000-3000 FEET WILL BE INCREASING TO THE 40-50KT RANGE SO LOW LEVEL WIND SHEAR HAS BEEN MAINTAINED IN THE BLF AND LWB WHERE THE SURFACE WINDS WONT BE AS STRONG AND GUSTY. && .PREV DISCUSSION... (ISSUED 1118 AM EDT FRI OCT 6 2006) SHORT TERM /REST OF TODAY/... LARGE AREA OF RAIN EXITED THE EASTERN COUNTY WARNING AREA BY 12Z WITH ONLY SCATTERED LIGHT RAIN FROM EASTERN WEST VIRIGNIA INTO SOUTH CENTRAL VIRGINIA AT 15Z. PRECIPITATION IS ORIENTED AROUND UPPER LOW NOW CENTERED IN EASTERN WEST VIRGINIA. LATEST RUC MODELS BRING UPPER LOW INTO THE MIDDLE OF THE COUNTY WARNING AREA BY 00Z TONIGHT. AS STEERING WINDS AROUND THE LOW BECOME MORE EAST AND NORTHEAST BETWEEN 18-21Z A MORE WIDEPSREAD AREA OF RAIN WILL SPREAD ACROSS THE FORECAST AREA. TEMPERATURES WILL ALSO DROP ALOFT WHICH SHOULD ENHANCE THE CLOUD COVER AND KEEP THE FORECSAT AREA STABLE ENOUGH TO PRVENT ANY THUNDER. SURFACE LOW IS NOW MOVING INTO EASTERN NORTH CAROLINA. SURFACE WINDS WILL INCREASE FROM THE NORTH AND NORTHEAST ALLOWING A BETTER SURGE OF COLD AIR ARRIVING BY LATE AFTERNOON. GUIDANCE AT ALL FORECAST SITES HAD TEMPERATURES DROPPING THIS AFTERNOON. THIS WILL BE REFLECTED IN THE GRIDDED DATABASE...ESPECIALLY IN THE NORTHEAST COUNTY WARNING AREA WHERE THE BEST COVERAGE OF RAIN WILL BE THIS AFTERNOON. PREV DISCUSSION... (ISSUED 643 AM EDT FRI OCT 6 2006) AVIATION... STRONG NE WINDS ALOFT WILL DEVELOP TODAY AS LOW PRES DEVELOPS ON THE COAST. 30 TO 40 KT WINDS CAN BE EXPECTED ABOVE ABOUT 1500 FEET BY AFTN. SOME OF THIS WIND WILL TRANSLATE TO THE SFC AND THINK INCREASE IN WIND SPEEDS FROM THE SFC TO 1500 WILL BE GRADUAL ENUF TO PRECLUDE LLWS AT DAN/LYH/ROA. LEFT LLWS IN LWB AND BLF FOR LATE TDA AND TNGT AS SFC WINDS LIKELY TO BECOME LIGHT. THESE WINDS ALOFT CONTINUE THRU 12Z SAT. LOOK FOR SOME IMPROVEMENT IN CIGS TODAY BUT NOT MUCH. MVFR IS PROBABLY AS GOOD AS IT GETS TODAY WITH ABUNDANT LOW LEVEL MOISTR IN PLACE FOR A WHILE. SFC WINDS FROM THE NE MAY KEEP VSBYS IN GOOD SHAPE FOR THE FIRST PART OF THE DAY...BUT THEN CHC OF RAIN INCREASES AND THUS LOWER (MVFR) VSBYS. RAIN CONTS TNGT WITH SLOWLY LOWERING CIGS AND VSBYS. PREV DISCUSSION... (ISSUED 259 AM EDT FRI OCT 6 2006) SHORT TERM /REST OF TODAY THROUGH MONDAY/... STRONG SHORTWAVE DIVING DOWN THRU THE OHIO VALLEY AND RESULTANT INCREASING DIVERGENCE OVER THE REGION PRODUCING WIDESPREAD RAINFALL COVERAGE. MEANWHILE COLD FRONT STALLED OVER THE SOUTHERN PORTIONS OF THE FCST AREA (FA) HAVING A HARD TIME PUSHING SOUTH THANKS TO ADVANCING UPPER WAVE AND STRENGTHENING SFC LOW NEAR CLT. THIS LOW WILL MOVE TO THE COAST TODAY WITH INCREASING NORTHERLY FLOW IN ITS WAKE REALLY PULLING DOWN THE COOL AIR. HIGH TEMPS WILL LIKELY BE EARLY THIS MORNING WITH FALLING TEMPS THE REST OF THE DAY. MEANWHILE RAIN SHIELD WILL SLOWLY MOVE EAST THIS MORNING...THEN AS UPPER WAVE CLOSES OFF OVER NC RAIN WILL WRAP BACK AROUND INTO THE MTNS AND PERSIST INTO THE OVERNIGHT PD TNGT. STRONG PRESSURE GRADIENT BETWEEN THE COASTAL LOW AND HIGH PRES OVER NEW ENGLAND WILL KEEP IMPRESSIVE LOW LVL NE FLOW AND VERY CHILLY TEMPS ACROSS THE FA THRU SATURDAY. SYSTEM BECOMES VERTICALLY STACKED BY SATURDAY RESULTING IN DECREASING DYNAMIC SPPT FOR RAINFALL. AREAS OF RAIN LIKELY TO ARND SATURDAY BUT MUCH MORE WIDELY SCTD. MODELS IN GOOD AGREEMENT ON THE UPR LOW DRIFTING SOUTH THRU THE WEEKEND WITH GRADUALLY IMPROVING CONDITIONS THROUGH MONDAY AS SFC HIGH PRESSURE PUSHES DOWN INTO THE MID-ATLANTIC REGION. PREV DISCUSSION... (ISSUED 845 PM EDT THU OCT 5 2006) SHORT TERM /REST OF TONIGHT/... EVENING TSTMS HAVE WEEKENED. HOWEVER...ANTICIPATE WIDESPREAD SHOWERS WITH EMBEDDED THUNDER DURING THE OVERNIGHT AS UPPER FLOW TRANSFORMS INTO HIGH AMPLITUED CONFIGURATION WITH BOOKEND CUTOFF LOWS ON EITHER SIDE OF THE MID CONUS RIDGE COME THIS TIME FRIDAY. SIGNIFICANT DINAMIC LIFT IF FCST OVER THE MID ATLANTIC THE NEXT 24 HOURS...THUS SO ANTICIPATING WET CONDITIONS TO PERSIST WITH 1-2 INCHES QPF THROUGH 00 UTC TOMORROW EVENING. A LITTLE CONCERNED ABOUT OVERALL QPF POTENTIAL. PWATS HAVE CLIMBED WELL ABOVE 1 INCH AT RNK/GSO...THE GSO SOUNDING A VERY MOIST 1.50. IF MODELS ARE CORRECT WITH DEEP EASTERLY FLOW SETTING UP EARLY FRIDAY...UPSLOPE FLOW AND SLOW CELL MOTION IN COMBINATION WITH THIS HIGH PWAT AIRMASS COULD EASIALLY SUPPORT RAIN RATES THAT WOULD RESULT IN MORE THAN 1-2 INCHES OF QPF. IF THIS OCCURS...MAY NEED TO CONSIDER FLOOD WATCH FOR SOME AREAS ALONG AND EAST OF THE BLUE RIDGE...IN SPITE OF THE LOW STREAM LEVELS. AVIATION... CIGS WILL GRADUALLY LOWER OVERNIGHT WITH WIDESPREAD AREAS OF RAIN WITH EMBEDDED TSRA. ANTICIPATE WIDESPREAD IFR CONDITIONS AFT 06 UTC...CONDITIONS PERSISTING THROUGH THE PD. PREV DISCUSSION... (ISSUED 351 PM EDT THU OCT 5 2006) SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/... MAIN CONCERN CONTINUES TO BE UPR LOW THAT WILL BE INFLUENCING THE LOCAL WX THRU THE SHORT TERM. LATE MORNING ANALYSIS SHOWED CONTINUED AMPLIFICATION OF UPR RIDGE ACRS THE CENTRAL CONUS...ALLOWING PIECE OF ENERGY DROPPING THRU THE GREAT LAKES THIS AFTN TO BEGIN DIGGING SHARPLY SOUTHWARD PER LATEST WV PICS. AT THE SFC...BACKDOOR FRONT MAKING GOOD PROGRESS SOUTHWARD EAST OF THE MOUNTAINS...WITH DRIER AIR BEGINNING TO FILTER SOUTH THRU NORTHERN VA. LOW LEVEL WINDS BACK TO THE SOUTHWEST TONIGHT AHEAD OF THE COLD FRONT. MSAS AND SPC ANALYSIS HAS BEST LIFT AND INSTABILITY ALONG THE SOUTHERN BLUE RIDGE INTO THE NORTH CAROLINA FOOTHILLS. LOW LEVEL CONVERGENCE IS MAXIMIZED IN THIS AREA AND RADAR IS ALREADY SHOWING THUNDERSTORMS DEVELOPING IN TAZEWELL...CARROL AND PATRICK COUNTIES. COVERAGE WILL BE BEST IN THE FOOTHILLS WITH ONLY SCATTERED SHOWERS FOR THE REST OF THE FORECAST AREA. WILL HAVE HIGHEST CHANCE OF RAIN IN THE SOUTHWEST COUNTY WARNING AREA THIS EVENING. BIG TRANSITION IN THE UPPER PATTERN TONIGHT AS SHORT WAVE OVER THE UPPER MISSISSIPPI VALLEY DIVES SOUTHEAST AND CLOSES OFF OVERNIGHT. BEST SYNOPTIC SCALE LIFT ARRIVES AFTER 03Z AND BY 06Z FORECAST AREA IN UNDER AN AREA OF STRONG UPPER DIFFLUENCE BETWEEN COUPLED JETS AND STRONG ISENTROPIC LIFT AROUND THE 300K LAYER. PRECIPITATBLE WATER VALUES HAVE BEEN CLIMBING FOR THE LAST FEW DAYS AND ARE NOW GREATER THAN 1.0 INCH. AT THE SURFACE THE PRIMARY LOW MOVES FROM THE TENNESSEE VALLEY INTO THE CAROLINAS BY FRIDAY MORNING. IN ADDITION...TONIGHT WILL BE THE START OF A BIG SURGE OF COLDER TEMPERATURES INTO THE AREA WITH 850 MB WINDS BECOMING NORTHEAST AND 850 MB TEMPERATURES DROPPING DOWN TO AROUND +6 IN THE NORTHWEST COUNTY WARNING AREA BY 12Z. SO PLAN TO INCREASE CHANCE OF RAIN ESPECIALLY IN THE 03-09Z TIME FRAME. RAISED MINIMUM TEMPERATURES IN THE EAST TONIGHT...CLOSER TO MAV GUIDANCE. MODEL GUIDANCE STILL IN GOOD AGREEMENT IN DROPPING CLOSED UPR SYSTEM SOUTH ACRS THE REGION THRU EARLY SATURDAY BEFORE FINALLY PUSHING TO THE SOUTHEAST COAST BY SUNDAY. THIS SHOULD MEAN AN EXTENDED PERIOD OF MAINLY CLOUDY AND COOL CONDITIONS...ALONG WITH OCCASIONAL RAIN CHANCES. BEST PRECIP CHANCES AFTER TONIGHT STILL APPEAR TO RESIDE OVER THE EASTERN HALF OF THE CWA IN CLOSEST PROXIMITY TO BEST FORCING INITIALLY...AND THEN IN AREA OF BETTER WARM ADVECTION WRAP AROUND PRECIP BY SATURDAY AS UPR LOW SINKS SOUTH. STILL HAVE QUESTIONS ABOUT SFC LOW DEVELOPMENT OFF THE COAST FRIDAY INTO SATURDAY. THINKING MODELS MAY BE UNDERDOING DEVELOPMENT GIVEN SUCH A STRONG SYSTEM ALOFT AND INCREASED BAROCLINICITY ALONG THE COAST. WILL RUN WITH THE IDEA OF A STRONGER SFC SYSTEM...WHICH IN CONTRAST TO STRONG SFC HIGH TO THE NORTH IS LIKELY TO CREATE SOME RATHER GUSTY WINDS ACRS THE PIEDMONT FRIDAY AFTN INTO FRIDAY NIGHT. TEMPS ON FRIDAY LIKELY TO GO NOWHERE (BUT DOWN IN THE AFTN) WITH STRONG COLD ADVECTION...CLOUDS...AND LIKELY OCCASIONAL RAIN. HIGHS TO COME EARLY FOR MANY AREAS AND HAVE FOLLOWED MAV MOS GUIDANCE WHICH LOOKS REASONABLE IN THIS SITUATION. OTHERWISE CONTINUED CLOUDY AND COOL FOR SATURDAY WITH PRECIP LINGERING OVR THE EAST. SYSTEM FINALLY LOOKS TO GIVE UP ITS INFLUENCE ON THE LOCAL WX BY SUNDAY ALTHOUGH DEEP EASTERLY FLOW MAY BE ENOUGH TO HOLD SOME LOWER CLOUDS AND COOLER TEMPS IN PLACE. LONG TERM /MONDAY THROUGH THURSDAY/... OVERALL PATTERN WILL BEGIN TO AMPLIFY MONDAY AS STUBBORN UPR LOW BEGINS TO FILL AND GETS SHUNTED FARTHER EAST GIVEN APPROACHING UPSTREAM SHORTWAVE TROUGH. THIS WILL ALLOW FOR A WARMER DAY ON MONDAY AS STRONG RIDGING ALOFT TO THE WEST FINALLY FOLDS OVER INTO THE REGION. PREVIOUSLY MENTIONED TROUGH APPROACHING ON LATE MONDAY/EARLY TUESDAY WILL DRIVE A WEAK COLD FRONT ACRS THE REGION EARLY IN THE DAY...BUT WITH LITTLE TO NO MOISTURE TO WORK WITH GIVEN RIDGING ACRS THE GULF...WILL HOLD ONTO A DRY FCST. PATTERN THEN BEGINS TO ONCE AGAIN UNDERGO SIGNIFICANT CHANGES BY THE LATTER HALF OF THE PERIOD...AS STRONG RIDGING DEVELOPING INTO THE GULF OF ALASKA HELPS CARVE OUT DEEPENING UPR TROUGH ACRS THE CENTRAL CONUS. WHILE SPECIFICS ON THE TIMING AND DEGREE OF TROUGHING CERTAINLY FAR FROM SET IN STONE...OVERALL PATTERN WOULD SUGGEST ONE OF BUILDING HEIGHTS ACRS THE AREA ON WEDNESDAY FOLLOWED BY A TRANSITION TO DEEP SOUTHWEST FLOW ALOFT BY THURSDAY. NOT YET READY TO ACCEPT THE EXTREMELY DEEP SYSTEM OVR THE NORTHERN PLAINS SUGGESTED BY THE GFS...BUT OTHER GLOBAL MODELS AND ENSEMBLE MEMBERS SUGGEST A LIKELIHOOD OF PRECIP BY THE END OF THE EXTENDED PERIOD. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...NONE. NC...NONE. WV...NONE. && $$ AMS va