AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 630 AM EST SAT NOV 11 2006 .UPDATE... QUICK UPDATE TO LOWER POPS FOR TODAY. LINE OF SHRA/TSRA HIT THE STATE LINE AND POW...VAPOR. NOT THAT THE MODELS WERE OFF ON THIS...BUT WAS EXPECTING AT LEAST A HUNDREDTH TO GET SQUEEZED OUT OVER MOST OF NW 1/3RD OF CWA. NOT SO SURE NOW UNLESS NEW ACTIVITY CAN DEVELOP THIS AFTERNOON. BEST CHC FOR MEASURABLE PRECIP WILL BE ACROSS NORTHERN ZONES. SNELSON && .SHORT TERM...(TODAY THROUGH MONDAY) HIGH AMPLITUDE SHORT WAVELENGTH SYSTEM TO MOVE FROM MISSOURI INTO NORTH GA TODAY AND THIS EVENING. LINE OF CONVECTION ALONG LEADING EDGE OF FRONT HAS BEEN VIGOROUS ALL MORNING LONG BUT IS FINALLY SHOWING SIGNS OF WEAKENING AS CG FREQUENCY WITHIN THE COMPLEX HAS DROPPED TO BELOW 100 STRIKES/15 MIN. NORTHERN AL LMA DATA NOT AVAILABLE ATTM. THIS WEAKENING ALSO PROGGED BY MODELS AS INSTABILITY WANES THIS MORNING. BY AFTERNOON...NO SFC-BASED CAPE INDICATED BY NMM/WRF OR GFS ACROSS CWA. COULD SEE SOME SCATTERED SHOWERS WITH AN ISOLATED STORMS AROUND TODAY BUT SVR STORMS APPEAR UNLIKELY GIVEN LIMITED INSTABILITY AND TIMING OF SYSTEM. FRONT SHOULD PROGRESS QUICKLY WITH STRONG WINDS DEVELOPING BEHIND FRONT. W TO NW WINDS OF 15-19 MPH WITH GUSTS OF 25-30 MPH EXPECTED THROUGH ABOUT 06Z TONIGHT. SHOULD REMAIN BELOW ADVISORY CRITERIA. SHOULD BE A VERY SUNNY DAY SUNDAY EVEN WITH SLIGHTLY COOLER WEATHER. TEMPS SHOULD COOL DRAMATICALLY BEHIND FRONT OVER WRN ZONES THIS AFTERNOON AND REST OF CWA TONIGHT. TEMPS STILL NOT TOO COLD DURING THE DAY WITH NEAR NORMAL READINGS EXPECTED. USED BIAS-ADJUSTED MAV GUIDANCE AND A BLEND OF MAV AND MET GUIDANCE FOR PERIODS WITH MORE DISAGREEMENT BETWEEN GUIDANCE. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) JUST TO SPITE ME...THE MEDIUM RANGE MODELS (ECMWF/GFS/DGEX) ARE NOW PROGGING A MONSTER TROUGH ALONG THE MISSISSIPPI VALLEY FOR WED. THE ONE FORECAST BY THE THURSDAY 18Z DGEX THAT THIS FORECASTER WAS DISSING THIS TIME YESTERDAY. YEA. WELL...WE WILL SEE HOW IT PANS OUT. WITH THIS AGREEMENT HAVE BUMPED POPS UP TO HIGH CHC CATEGORY FOR WED AND WED NIGHT...NOT QUITE THE LIKELIES AS MEX HAS. INDICATED TSRA FOR WED. IF MONSTER TROUGH AND 990MB SFC LOW OVER SRN INDIANA VERIFIES... COULD SEE SOME SVR STORMS POSSIBLE. && .FIRE DANGER... SHOULD BE IN GOOD SHAPE THROUGH SUNDAY WITH SOMEWHAT MOIST CONDITIONS EXPECTED. COULD SEE SOME CRITICAL RH VALUES MET FOR SEVERAL HOURS ON MONDAY. WILL NEED TO MONITOR THIS FOR POSSIBLE FIRE WEATHER WATCH. SNELSON && .AVIATION... WINDS A LITTLE LIGHTER THAN EXPECTED THIS MORNING...BUT THEY SHOULD PICK UP THROUGH THE MORNING HOURS AS THE COLD FRONT APPROACHES. THIS WITH RADIATIONAL COOLING HAS ALLOWED FOG TO DEVELOP AT CLIMATOLOGICALLY PREFERRED SITES. SOME HIGH CLOUDS HAVE ALREADY FILTERED IN...ONCE MID AND LOWER CLOUDS MOVE IN SOME OF THE FOG FORMATION WILL BE SHUT DOWN SINCE COOLING POTENTIAL WILL BE SLOWED. CONVECTION THAT WAS ONGOING THROUGH THE VERY EARLY MORNING HOURS HAS FIZZLED OUT OVER MS/AL...BUT NAM/RUC BOTH SEEM TO THINK THAT PRECIP WILL REDEVELOP LATER THIS AFTERNOON WITH DAYTIME HEATING. THUS... PLAN TO BRING IN LOWER CLOUDS AT BEGINNING OF TAF PERIOD...WITH SOME MENTION OF SHOWERS FOR THE AFTERNOON PERIOD. WRAPAROUND COLD-AIR STRATOCU WITH CAA ALOFT WILL LIKELY KEEP CEILINGS LOW FOR MOST OF THE REMAINDER OF THE PERIOD AS WINDS SHIFT AROUND TO THE NORTHWEST AND INCREASE TO AT LEAST 15KT WITH HIGHER GUSTS...SEE PUBLIC DISCUSSION ABOVE. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 72 42 64 35 / 50 20 0 5 ATLANTA 67 39 62 39 / 40 10 0 5 BLAIRSVILLE 63 39 58 31 / 60 20 0 5 CARTERSVILLE 64 38 60 31 / 60 10 0 5 COLUMBUS 70 43 67 38 / 30 5 0 5 GAINESVILLE 67 41 61 38 / 50 20 0 5 MACON 77 40 70 33 / 30 10 0 5 ROME 58 40 62 31 / 70 10 0 5 PEACHTREE CITY 69 39 63 30 / 40 10 0 5 VIDALIA 80 47 69 39 / 20 20 0 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 13 ga AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE PEACHTREE CITY GA 530 AM EST SAT NOV 11 2006 .SHORT TERM...(TODAY THROUGH MONDAY) HIGH AMPLITUDE SHORT WAVELENGTH SYSTEM TO MOVE FROM MISSOURI INTO NORTH GA TODAY AND THIS EVENING. LINE OF CONVECTION ALONG LEADING EDGE OF FRONT HAS BEEN VIGOROUS ALL MORNING LONG BUT IS FINALLY SHOWING SIGNS OF WEAKENING AS CG FREQUENCY WITHIN THE COMPLEX HAS DROPPED TO BELOW 100 STRIKES/15 MIN. NORTHERN AL LMA DATA NOT AVAILABLE ATTM. THIS WEAKENING ALSO PROGGED BY MODELS AS INSTABILITY WANES THIS MORNING. BY AFTERNOON...NO SFC-BASED CAPE INDICATED BY NMM/WRF OR GFS ACROSS CWA. COULD SEE SOME SCATTERED SHOWERS WITH AN ISOLATED STORMS AROUND TODAY BUT SVR STORMS APPEAR UNLIKELY GIVEN LIMITED INSTABILITY AND TIMING OF SYSTEM. FRONT SHOULD PROGRESS QUICKLY WITH STRONG WINDS DEVELOPING BEHIND FRONT. W TO NW WINDS OF 15-19 MPH WITH GUSTS OF 25-30 MPH EXPECTED THROUGH ABOUT 06Z TONIGHT. SHOULD REMAIN BELOW ADVISORY CRITERIA. SHOULD BE A VERY SUNNY DAY SUNDAY EVEN WITH SLIGHTLY COOLER WEATHER. TEMPS SHOULD COOL DRAMATICALLY BEHIND FRONT OVER WRN ZONES THIS AFTERNOON AND REST OF CWA TONIGHT. TEMPS STILL NOT TOO COLD DURING THE DAY WITH NEAR NORMAL READINGS EXPECTED. USED BIAS-ADJUSTED MAV GUIDANCE AND A BLEND OF MAV AND MET GUIDANCE FOR PERIODS WITH MORE DISAGREEMENT BETWEEN GUIDANCE. .LONG TERM...(MONDAY NIGHT THROUGH FRIDAY) JUST TO SPITE ME...THE MEDIUM RANGE MODELS (ECMWF/GFS/DGEX) ARE NOW PROGGING A MONSTER TROUGH ALONG THE MISSISSIPPI VALLEY FOR WED. THE ONE FORECAST BY THE THURSDAY 18Z DGEX THAT THIS FORECASTER WAS DISSING THIS TIME YESTERDAY. YEA. WELL...WE WILL SEE HOW IT PANS OUT. WITH THIS AGREEMENT HAVE BUMPED POPS UP TO HIGH CHC CATEGORY FOR WED AND WED NIGHT...NOT QUITE THE LIKELIES AS MEX HAS. INDICATED TSRA FOR WED. IF MONSTER TROUGH AND 990MB SFC LOW OVER SRN INDIANA VERIFIES... COULD SEE SOME SVR STORMS POSSIBLE. && .FIRE DANGER... SHOULD BE IN GOOD SHAPE THROUGH SUNDAY WITH SOMEWHAT MOIST CONDITIONS EXPECTED. COULD SEE SOME CRITICAL RH VALUES MET FOR SEVERAL HOURS ON MONDAY. WILL NEED TO MONITOR THIS FOR POSSIBLE FIRE WEATHER WATCH. SNELSON && .AVIATION... WINDS A LITTLE LIGHTER THAN EXPECTED THIS MORNING...BUT THEY SHOULD PICK UP THROUGH THE MORNING HOURS AS THE COLD FRONT APPROACHES. THIS WITH RADIATIONAL COOLING HAS ALLOWED FOG TO DEVELOP AT CLIMATOLOGICALLY PREFERRED SITES. SOME HIGH CLOUDS HAVE ALREADY FILTERED IN...ONCE MID AND LOWER CLOUDS MOVE IN SOME OF THE FOG FORMATION WILL BE SHUT DOWN SINCE COOLING POTENTIAL WILL BE SLOWED. CONVECTION THAT WAS ONGOING THROUGH THE VERY EARLY MORNING HOURS HAS FIZZLED OUT OVER MS/AL...BUT NAM/RUC BOTH SEEM TO THINK THAT PRECIP WILL REDEVELOP LATER THIS AFTERNOON WITH DAYTIME HEATING. THUS... PLAN TO BRING IN LOWER CLOUDS AT BEGINNING OF TAF PERIOD...WITH SOME MENTION OF SHOWERS FOR THE AFTERNOON PERIOD. WRAPAROUND COLD-AIR STRATOCU WITH CAA ALOFT WILL LIKELY KEEP CEILINGS LOW FOR MOST OF THE REMAINDER OF THE PERIOD AS WINDS SHIFT AROUND TO THE NORTHWEST AND INCREASE TO AT LEAST 15KT WITH HIGHER GUSTS...SEE PUBLIC DISCUSSION ABOVE. && .PRELIMINARY POINT TEMPS/POPS... ATHENS 72 42 64 35 / 50 20 0 5 ATLANTA 67 39 62 39 / 40 10 0 5 BLAIRSVILLE 63 39 58 31 / 60 20 0 5 CARTERSVILLE 64 38 60 31 / 60 10 0 5 COLUMBUS 70 43 67 38 / 30 5 0 5 GAINESVILLE 67 41 61 38 / 50 20 0 5 MACON 77 40 70 33 / 30 10 0 5 ROME 58 40 62 31 / 70 10 0 5 PEACHTREE CITY 69 39 63 30 / 40 10 0 5 VIDALIA 80 47 69 39 / 20 20 0 5 && .FFC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 13 ga AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CARIBOU ME 1011 AM EST SAT NOV 11 2006 .SYNOPSIS...CLOUDS WILL THICKEN ACROSS THE REGION AS AN APPROACHING WARM FRONT LIFTS NORTH AND STALLS OVER NORTH CENTRAL MAINE LATE THIS AFTERNOON. RAIN WILL OVERSPREAD NORTHWEST AREAS LATE THIS AFTERNOON AND SPREAD ACROSS THE REMAINDER OF THE REGION TONIGHT. COLDER AIR FILTERING INTO EXTREME NORTHERN MAINE WILL CHANGE THE RAIN TO SNOW LATER TONIGHT. UNSETTLED WEATHER IS EXPECTED TO CONTINUE ONTO EARLY NEXT WEEK. && .SHORT TERM /REST OF TODAY/... BASED ON THE LATEST RUC MODEL FORECAST DECIDED TO DECREASE THE CHANCE OF PRECIPITATION FROM ALL ZONES TODAY. RUC ALONG WITH 12Z NAM WRF INDICATE THAT RAIN WILL OVERSPREAD NORTHWEST MAINE ESPECIALLY NORTHERN ZONES 1 AND 3 BY LATE AFTERNOON BUT SHOULD HOLD OFF UNTIL AFTER SUNSET ELSEWHERE. SAT AND RADAR TRENDS ALSO SUPPORT THIS AS WELL. ALSO...ADJUSTED SKY EARLY ON BASED ON SAT TRENDS AND ONLY TWEAKED HIGH TEMPS UP A NOTCH TODAY BASED ON CURRENTS OBS. && .MARINE... NO CHANGES. && .PREVIOUS DISCUSSION... SHORT TERM /TODAY THROUGH SUNDAY/... WEAK SURFACE RIDGE THAT BROUGHT DRY CONDITIONS TO THE CWA DURING THE LAST TWENTY FOUR HOURS WILL MOVE OFF TO THE EAST EARLY THIS MORNING. LATEST IR SATELLITE LOOP INDICATING CLOUDS ALREADY SPREADING OVER THE NORTHERN AND NORTH CENTRAL ZONES WITH WARM ADVECTION PATTERN SETTING UP ON THE BACK SIDE OF THE RIDGE AND WITHIN THE DEVELOPING FRONTOGENETIC ZONE OFF TO THE SOUTHWEST. THE FORECAST IN THE SHORT TERM HINGES ON STRENGTH OF THE LOW LEVEL FRONTOGENESIS AND ACCOMPANYING LARGE SCALE LIFT RESULTING IN THE OVERRUNNING PATTERN THAT SETS UP ACROSS THE NORTHERN PORTION OF THE CWA THIS AFTERNOON INTO TONIGHT. BOTH THE NAM WRF AND GFS INCREASE THE LOW LEVEL Q-VECTOR FORCING AND CONVERGENCE STRENGTHENING THE BAROCLINIC ZONE THROUGH NORTH CENTRAL MAINE TODAY. INCREASING LOW LEVEL SOUTHERLY FLOW AND MOISTURE CONVERGENCE ALONG/NORTH OF THE FRONT WILL ESTABLISH A BAND PRECIPITATION ACROSS THE FAR NORTH. HAVE INCREASED TO POPS TO LIKELY FOR ZONE 1 WITH HIGH CHANCE CONTINUING FOR ZONES 2>4 THIS AFTERNOON. MODEL SOUNDINGS SUGGEST PRECIPITATION TO BEGIN AS RAIN...HOWEVER AS SURFACE HIGH OVER CENTRAL QUEBEC PROVINCE BUILDS AND ENHANCES A NORTHEAST LOW LEVEL FLOW NORTH OF THE WARM FRONT...THE COLUMN COOLS CONSIDERABLY ESPECIALLY AFTER MIDNIGHT TO AOB FREEZING ACROSS NORTHWEST MAINE AND THROUGHOUT THE SAINT JOHN VALLEY. IN-HOUSE SNOW TOOL SUGGESTS UP TO AN INCH ACROSS THE ALLAGASH WILDERNESS AND SAINT JOHN VALLEY WITH UP TO 3 INCHES ACROSS THE BIG TWENTY TOWNSHIP /ESTCOURT STATION/ BY EARLY SUNDAY MORNING. SOME MIXED PRECIPITATION ALSO POSSIBLE ACROSS EXTREME NORTHERN ZONE 2 FROM VAN BUREN TO HAMLIN WITH LITTLE IF ANY ACCUMULATION EXPECTED. ELSEWHERE EXPECT RAIN TO DEVELOP ACROSS DOWNEAST EARLY TONIGHT. LOW LEVEL SUPPORT GRADUALLY WEAKENS AS FRONTAL BOUNDARY SLOWLY MOVES TOWAD THE COAST LATE TONIGHT AND SUNDAY MORNING. HAVE REFLECTED THIS THINKING WITH LOWERING POPS ACROSS THE NORTH AND A GRADUAL INCREASE IN POPS DOWNEAST FOR SUNDAY. WENT BELOW THE MOS GUIDANCE FOR MAX TEMPERATURES ON SUNDAY WHICH LOCAL STUDY SUPPORTS WITH NORTH TO NORTHEAST CAA IN PLACE. LONG TERM /SUNDAY NIGHT THROUGH TUESDAY/... STILL SOME MAJOR DISAGREEMENTS ON THE MOVEMENT OF MID ATLC LOW EARLY NEXT WEEK. GFS THE MORE PROGRESSIVE MODEL...EJECTING LOW ACROSS THE STATE ON TUESDAY NIGHT WITH THE ECMWF WAITING UNTIL WEDNESDAY. STRONG HIGH PRESSURE NORTH OF THE STATE COMBINED WITH LOW PRESSURE SOUTH OF THE AREA WILL KEEP MOIST EASTERLY FLOW ACROSS THE STATE. WITH EITHER MODEL SOLUTION EXPECT PLENTY OF CLOUDS AND OCCASIONAL SHOWERS SUNDAY NIGHT THROUGH TUESDAY. AVIATION...VFR CONDITIONS EXPECTED ACROSS THE NORTH THIS MORNING... THEN MVFR/IFR CIGS DEVELOPING WITH OVERRUNNING PATTERN ACROSS THE NORTHERN TAF SITES THIS AFTERNOON AND TONIGHT. VFR CONDITIONS FOR DOWNEAST TODAY...THEN MVFR CONDITIONS WITH APPROACHING FRONT AND MOIST SOUTHERLY FLOW OFF THE ATLANTIC TONIGHT. MARINE... SHORT TERM: SWELL AROUND 6 FT STILL OCCURRING OVER THE WATERS EARLY THIS MORNING. WILL CONTINUE WITH SCA HEADLINE AS EXPECT WINDS TO INCREASE TO SCA CRITERIA /IN GUSTS/ WITH SOUTHERLY FLOW INCREASING THIS AFTERNOON INTO EARLY TONIGHT. LONG TERM: COMBINATION OF HIGH PRESSURE TO THE NORTH AND LOW PRESSURE TO THE SOUTH WILL PRODUCE EASTERLY FLOW OVER THE WATERS EARLY NEXT WEEK. AS GRADIENT CONTINUES TO TIGHTEN BETWEEN THESE TWO SURFACE FEATURES...EXPECT SEAS AND WINDS TO INCREASE TO SCA CRITERIA DURING THIS TIME. && CAR WATCHES/WARNINGS/ADVISORIES... ME...NONE. MARINE...SMALL CRAFT ADVISORY FOR ANZ050 UNTIL 5 PM SATURDAY. && $$ SHORT TERM UPDATE...DUDA me AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 1000 PM EST SAT NOV 11 2006 .UPDATE... MAIN FCST ISSUES OVERNIGHT ARE CLOUDS/TEMPS. EVENING SATELLITE IMAGERY SHOWS STRATOCU DECK HANGING TOUGH ACROSS UPPER MI. THERE HAVE BEEN A FEW TRANSIENT SMALL BREAKS IN THE CLOUD COVER OVER A PORTION OF CNTRL UPPER MI...BUT BREAKS HAVE FILLED IN FOR THE MOST PART RECENTLY. MOISTURE IS TRAPPED BLO SHARP INVERSION BASED AT ABOUT 3.5KFT AGL PER TAMDAR SOUNDING FROM FLIGHT OUT OF KSAW JUST BEFORE 01Z. ALTHOUGH SFC RIDGE IS PASSING ACROSS UPPER MI ATTM...NOT TOO CONFIDENT ABOUT SIGNIFICANT CLEARING OVERNIGHT... ESPECIALLY CONSIDERING THAT WINDS INTIALLY AFTER RIDGE PASSAGE WILL BE A SE UPSLOPING FLOW OFF LAKE MICHIGAN FOR A GOOD PORTION OF THE FCST AREA. HOWEVER...SE TO S FLOW OVER FAR WRN UPPER MI TOWARD LAKE SUPERIOR IS DOWNSLOPING AND THAT SHOULD PROMOTE SOME BREAK UP OF STRATOCU THERE. OTHERWISE...AS FLOW BECOMES STRONGER AND SRLY VERY LATE TONIGHT/EARLY SUN MORNING...STRATOCU SHOULD BEGIN TO BREAK UP ALL AREAS. THIS IS ALREADY UNDERWAY ACROSS SW WI. WITH MORE CLOUD COVER EXPECTED THRU THE NIGHT...HAVE BUMPED MIN TEMPS UP INTO THE 20S EVERYWHERE. IF ANY PERSISTENT HOLES IN THE CLOUD COVER SHOULD DEVELOP OVER THE CNTRL/E WHERE SNOWCOVER IS PRESENT...TEMPS WILL DROP INTO THE TEENS. && .PREV DISCUSSION... ISSUED AT 354 PM EST SYNOPSIS... WV LOOP AND RUC ANALYSIS INDICATED A PROGRESSIVE PATTERN WITH A POSITIVE TILT MID/UPPER LEVEL TROF FROM ERN ONTARIO AND LWR MI TO THE LWR MS VALLEY...AN UPSTREAM RIDGE FROM THE SRN PLAINS TO THE UPPER MS VALLEY AND ANOTHER TROUGH OVER THE WRN CONUS. AT THE SFC...LOW PRES WAS LOCATED E OF LAKE ONTARIO WHILE A RIDGE EXTENDED FROM NRN ONTARIO AND WRN LAKE SUPERIOR THROUGH IA TO TX. SRLY FLOW WAS INCREASING OVER THE PLAINS AND UPPER MS VALLEY AHEAD OF A TROUGH FROM SRN SASK INTO ERN WY. VIS IMAGERY SHOWED LOW CLOUDS LINGERING OVER FROM WRN LK SUPERIOR INTO NW WI..BENEATH STRONG 850 MB INVERSION...PER 19Z KCMX TAMDAR SOUNDING. MORE CELLULAR LAKE EFFECT CLOUDS PERSISTED WITH NNE FLOW FROM E LK SUPERIOR INTO CNTRL AND E UPPER MI. 850 MB TEMPS NEAR -10C PROVIDED ENOUGH INSTABILITY FOR CONTINUED LIGHT LES THIS AFTERNOON. HOWEVER...RADAR SHOWED MAINLY JUST SCT -SHSN OR FLURRIES. SHORT TERM (TONIGHT AND SUNDAY)... MAIN FCST CONCERNS ARE CLOUD TRENDS AND IMPACTS ON TEMPS. ANY LINGERING LES OVER CNTRL UPR MI SHOULD DIMINISH AND END EARLY THIS EVENING AS THE WINDS BECOME VARIABLE AND EVENTUALLY OFFSHORE. ALTHOUGH THE CLOUD DECK HAS BEEN SLOWLY ERODING OVER NW WI...THE STRENGTH OF THE INVERSION AND LACK OF SIGNIFICANT DRY ADVECTION HAS HINDERED ANY CLEARING. THE 18Z RUC SUGGESTS THAT AS THE RDG AXIS SLIDES TO THE EAST RETURN SRLY FLOW WILL PUSH THE CLOUDS NORTH OF UPPER MI WHILE THE NAM...AS IS OFTEN THE CASE WITH LOW LVL MOISTURE...IS MORE PESSIMISTIC. GIVEN THE AMOUNT OF CLOUDS THROUGH CNTRL WI...A SLOWER DEPARTURE OF LOWER CLOUDS LOOKS MORE LIKELY. IN ADDITION...HIGHER CLOUDS AHEAD OF THE WRN CONUS TROUGH WERE ALREADY STREAMING TOWARD THE WRN LAKES. COMBINATION OF GREATER CLOUD COVER AND INCREASING S WINDS LATE TONIGHT OVER THE WEST HALF SHOULD KEEP TEMPS FROM DROPPING OFF AS FAR...EVEN WITH THE ABUNDANT SNOW COVER IN PORTIONS OF CNTRL AND E UPR MI. THERE MAY BE SOME LINGERING LOW CLOUDS INTO CNTRL UPR MI LATE TONIGHT INTO SUN WITH LONG SRLY FETCH DEVELOPING ACROSS LAKE MI AND 925 MB TEMPS FCST NEAR -4C. OTHERWISE...SOME SUNSHINE THROUGH INCREASING HIGH CLOUDS SHOULD PREVAIL SUNDAY. SNOW COVER SHOULD AGAIN KEEP TEMPS AOB GUIDANCE FOR INLAND PORTIONS OF CNTRL UPR MI. LONG TERM (SUNDAY NIGHT THROUGH NEXT SATURDAY)... MAIN FORECAST CONCERN IS MODERATE TO HEAVY PERIOD OF SNOW SUNDAY NIGHT INTO MONDAY. SUNDAY NIGHT...SHRTWV TROUGH EXTENDING FROM WASHINGTON INTO CALIFORNIA IS PROGGED TO BE LOCATED OVER THE PLAINS AT 00Z. SINCE FAIRLY STRONG UPPER LEVEL RIDGING IS EXPECTED AHEAD OF THE TROUGH OVER THE EAST COAST...THIS TROUGH WILL HAVE TO LIFT NORTHEAST TOWARDS THE CWA. BY 12Z...THE TROUGH SHOULD BE LOCATED IN WESTERN WISCONSIN. THE TRACK OF THE TROUGH ALSO ALLOWS FOR A 100KT JET STREAK...WHICH SHOULD BE JUST SOUTH OF OMAHA AT 00Z MON...TO TRACK UP TO SAULT SAINTE MARIE BY 12Z...PLACING MUCH OF THE CWA IN THE LEFT EXIT REGION (FAVORED FOR UPPER LEVEL DIVERGENCE). IN ADDITION TO THE FAVORABLE UPPER JET TRACK...NAM/GFS SHOW DECENT MID-LEVEL FRONTOGENESIS MOVING THROUGH...ADDING EXTRA VERTICAL MOTION. OTHER THAN FOR SOME INITIAL DRY AIR...PARTICULARLY OVER THE EASTERN CWA...CONDITIONS LOOK FAVORABLE FOR BRINGING PRECIPITATION ACROSS MUCH OF THE CWA BY 12Z. SINCE MODELS HAVE BEEN SHOWING THIS FEATURE FOR A WHILE...HAVE RAISED POPS TO CATEGORICAL. MOST TEMPERATURE PROFILES ON SOUNDINGS WHEN THE PRECIPITATION IS MOVING THROUGH IS ALL BELOW FREEZING...EXCEPT IMMEDIATELY ALONG LAKE MICHIGAN... THEREFORE MAINLY SNOW IS EXPECTED. AS FOR AMOUNTS...GIVEN THE STRONG VERTICAL MOTION...AT LEAST A 0.25 INCH OF LIQUID SHOULD BE POSSIBLE. BECAUSE OF THE SYNOPTIC NATURE OF THE SYSTEM...A 10 TO 1 SNOWFALL RATIO WOULD BE APPROPRIATE...HOWEVER WITH THE SATURATED SNOW GROWTH LAYER A FEW THOUSAND FEET DEEP AND PLENTY OF VERTICAL MOTION IN THAT LAYER...WILL USE A 15 TO 1 RATIO TO ACCOUNT FOR MORE SNOWFALL. ADVISORIES MAY BE NEEDED FOR THIS EVENT IF SLIGHTLY MORE QPF OCCURS THAN EXPECTED. MONDAY...SHRTWV TROUGH WILL CONTINUE MOVING NORTHEASTWARD...CROSSING MOST OF THE CWA BY 00Z. IN FACT...SOME WEAK UPPER LEVEL RIDGING IS PROGGED TO BUILD INTO FAR WESTERN LAKE SUPERIOR BY 00Z AHEAD OF TROUGHING DEVELOPING OVER THE NW U.S.. EXPECT THE BAND OF FRONTOGENETIC SNOWFALL TO PROGRESS EASTWARD ACROSS THE CWA WITH THE SHRTWV TROUGH...AND SKIES GRADUALLY CLEARING OUT BEHIND IT. WITH 850MB TEMPS RISING TO AROUND -2C BY THE END OF THE DAY...TEMPERATURES SHOULD STILL BE ABLE TO HIT THE UPPER 30S/LOW 40S. MONDAY NIGHT...UPPER LEVEL RIDGING IS PROGGED TO ENCOMPASS THE CWA THROUGH THE NIGHT WHILE THE TROUGHING OVER THE NW MOVES TOWARDS THE PLAINS. SKIES SHOULD CLEAR OUT ACROSS MUCH OF THE CWA DURING THE EVENING DUE TO A COMBINATION OF DRY AIR ADVECTION...MID/UPPER LEVEL SUBSIDENCE AND LOW LEVEL ANTICYCLONIC FLOW FROM A HIGH PRESSURE RIDGE MOVING ACROSS. THESE FACTORS WILL ALLOW TEMPERATURES TO DROP FAIRLY QUICKLY. BY 12Z...THE SURFACE HIGH PRESSURE RIDGE IS PROGGED OVER THE EASTERN CWA...ALLOWING RETURN FLOW TO SET UP IN THE WESTERN U.P.. THEREFORE THIS AREA COULD SEE RISING TEMPERATURES AFTER MIDNIGHT. IN ADDITION...HIGH CLOUDS ARE EXPECTED TO INCREASE ACROSS THE CWA AFTER MIDNIGHT AS THE UPPER LEVEL RIDGE MOVES SLIGHTLY EASTWARD...WHICH SHOULD KEEP TEMPERATURES FROM DROPPING TOO LOW. STILL WENT CLOSE TO COOP GUIDANCE...THOUGH...GIVEN THE AMOUNT OF GOOD RADIATIONAL COOLING. TUESDAY...AN UPPER LEVEL TROUGH IS EXPECTED TO COVER MUCH OF THE PLAINS STATES BY 00Z WED...SIMILAR TO THAT OF 00Z MON BUT DEEPER. GFS/ECMWF INDICATE THAT A WEAK SHRTWV MAY MOVE ACROSS THE CWA DURING THE DAY. HOWEVER...RH PROFILES ARE VERY DRY...SO LIKELY THE MAIN IMPACT FROM THIS SHRTWV WILL BE FOR INCREASING MID/HIGH CLOUDS. ANOTHER SHRTWV IS PROGGED TO APPROACH THE WESTERN U.P. LATE IN THE DAY. THIS SHRTWV WILL BE ASSOCIATED WITH MORE ISENTROPIC LIFT AND MOISTURE...SO HAVE MAINTAINED A CHANCE OF RAIN/SNOW THERE. AS FAR AS TEMPERATURES GO...WITH QUITE A BIT OF CLOUD COVER EXPECTED...HAVE STAYED CLOSER TO MAV GUIDANCE. TUESDAY NIGHT THROUGH SATURDAY...OPERATIONAL MODELS ARE IN FAIRLY GOOD AGREEMENT REGARDING THE MOVEMENT OF THE UPPER LEVEL TROUGH...TAKING IT FROM THE PLAINS TUESDAY EVENING TO THE OHIO VALLEY BY THURSDAY MORNING...AND THEN INTO THE NORTHEAST U.S. ON FRIDAY. THE 12Z UKMET IS SLIGHTLY SLOWER IN THE MOTION OF THIS TROUGH COMPARED TO THE 12Z ECMWF/GFS...BUT GIVEN THE GOOD AGREEMENT...THIS SPEED DIFFERENCE IS NOT A BIG ISSUE. AS FAR AS THE TROUGH\S IMPACTS ON THE CWA\S WEATHER...ISENTROPIC LIFT AND HEIGHT FALLS AHEAD OF THE TROUGH MAY BRING SOME LIGHT SNOW OR RAIN INTO THE CWA TUESDAY NIGHT INTO WEDNESDAY. AS COLD AIR FLOWS IN BEHIND THE TROUGH ON WEDNESDAY NIGHT...THE PRECIPITATION SHOULD CHANGE OVER TO ALL SNOW. HOWEVER...THE AMOUNT OF COLD AIR IS NOT THAT SIGNIFICANT...WITH THE GFS (WHICH TYPICALLY HAS A COLD BIAS OUT IN THE EXTENDED) INDICATING 850MB TEMPS OF -2 TO -4C AT 12Z THU. SINCE LAKE SUPERIOR WATER TEMPERATURES ARE ONLY AROUND 6C...NO LAKE EFFECT IS EXPECTED. AS THE UPPER TROUGH LIFTS NORTHEASTWARD TOWARDS THE NORTHEAST U.S. THURSDAY...WARMER ATLANTIC AIR WRAPS BACK TOWARDS UPPER MICHIGAN. THEREFORE HAVE INCLUDED A MIX WITH RAIN AGAIN FOR THURSDAY ACROSS THE U.P....THEN ACROSS THE EASTERN CWA THURSDAY NIGHT. UPPER LEVEL FLOW FOR FRIDAY INTO SATURDAY IS EXPECTED TO BECOME WEST-NORTHWESTERLY...WHICH FAVORS FAST MOVING SHRTWVS TO SLIDE THROUGH UPPER MICHIGAN. ONE OF THESE SHRTWVS THE GFS/ECMWF SHOW MOVING THROUGH LATE FRIDAY INTO FRIDAY NIGHT. HAVE INCLUDED A SLIGHT CHANCE OF RAIN/SNOW WITH THIS FEATURE. THE 12Z ECMWF/GFS INDICATE THAT THE 850MB TEMPS WILL FALL TO AROUND -8C BEHIND THE SHRTWV EARLY SATURDAY MORNING OVER EASTERN LAKE SUPERIOR...THEN WARM QUICKLY THROUGH THE DAY. THEREFORE THERE MIGHT BE A BRIEF PERIOD OF LAKE EFFECT...BUT FOR NOW PREFER TO LEAVE SATURDAY DRY WITH THE THINKING THAT MUCH OF THE LAKE EFFECT WILL OCCUR FRIDAY NIGHT...IF ANY. TEMPERATURES THROUGH THE EXTENDED SHOULD REMAIN AT OR JUST SLIGHTLY ABOVE NORMAL GIVEN RELATIVELY MILD 850MB TEMPS THROUGH THE PERIOD. LOOKING OUT BEYOND SATURDAY INTO THE WEEK AFTER...PATTERN LOOKS NEARLY ZONAL WHICH FAVORS CONTINUED PACIFIC AIRMASSES. THEREFORE TEMPERATURES SHOULD STAY NEAR OR ABOVE NORMAL. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ROLFSON (UPDATE) JLB (SHORT TERM) AJ (LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 354 PM EST SAT NOV 11 2006 .SYNOPSIS... WV LOOP AND RUC ANALYSIS INDICATED A PROGRESSIVE PATTERN WITH A POSITIVE TILT MID/UPPER LEVEL TROF FROM ERN ONTARIO AND LWR MI TO THE LWR MS VALLEY...AN UPSTREAM RIDGE FROM THE SRN PLAINS TO THE UPPER MS VALLEY AND ANOTHER TROUGH OVER THE WRN CONUS. AT THE SFC...LOW PRES WAS LOCATED E OF LAKE ONTARIO WHILE A RIDGE EXTENDED FROM NRN ONTARIO AND WRN LAKE SUPERIOR THROUGH IA TO TX. SRLY FLOW WAS INCREASING OVER THE PLAINS AND UPPER MS VALLEY AHEAD OF A TROUGH FROM SRN SASK INTO ERN WY. VIS IMAGERY SHOWED LOW CLOUDS LINGERING OVER FROM WRN LK SUPERIOR INTO NW WI..BENEATH STRONG 850 MB INVERSION...PER 19Z KCMX TAMDAR SOUNDING. MORE CELLULAR LAKE EFFECT CLOUDS PERSISTED WITH NNE FLOW FROM E LK SUPERIOR INTO CNTRL AND E UPPER MI. 850 MB TEMPS NEAR -10C PROVIDED ENOUGH INSTABILITY FOR CONTINUED LIGHT LES THIS AFTERNOON. HOWEVER...RADAR SHOWED MAINLY JUST SCT -SHSN OR FLURRIES. && .SHORT TERM (TONIGHT AND SUNDAY)... MAIN FCST CONCERNS ARE CLOUD TRENDS AND IMPACTS ON TEMPS. ANY LINGERING LES OVER CNTRL UPR MI SHOULD DIMINISH AND END EARLY THIS EVENING AS THE WINDS BECOME VARIABLE AND EVENTUALLY OFFSHORE. ALTHOUGH THE CLOUD DECK HAS BEEN SLOWLY ERODING OVER NW WI...THE STRENGTH OF THE INVERSION AND LACK OF SIGNIFICANT DRY ADVECTION HAS HINDERED ANY CLEARING. THE 18Z RUC SUGGESTS THAT AS THE RDG AXIS SLIDES TO THE EAST RETURN SRLY FLOW WILL PUSH THE CLOUDS NORTH OF UPPER MI WHILE THE NAM...AS IS OFTEN THE CASE WITH LOW LVL MOISTURE...IS MORE PESSIMISTIC. GIVEN THE AMOUNT OF CLOUDS THROUGH CNTRL WI...A SLOWER DEPARTURE OF LOWER CLOUDS LOOKS MORE LIKELY. IN ADDITION...HIGHER CLOUDS AHEAD OF THE WRN CONUS TROUGH WERE ALREADY STREAMING TOWARD THE WRN LAKES. COMBINATION OF GREATER CLOUD COVER AND INCREASING S WINDS LATE TONIGHT OVER THE WEST HALF SHOULD KEEP TEMPS FROM DROPPING OFF AS FAR...EVEN WITH THE ABUNDANT SNOW COVER IN PORTIONS OF CNTRL AND E UPR MI. THERE MAY BE SOME LINGERING LOW CLOUDS INTO CNTRL UPR MI LATE TONIGHT INTO SUN WITH LONG SRLY FETCH DEVELOPING ACROSS LAKE MI AND 925 MB TEMPS FCST NEAR -4C. OTHERWISE...SOME SUNSHINE THROUGH INCREASING HIGH CLOUDS SHOULD PREVAIL SUNDAY. SNOW COVER SHOULD AGAIN KEEP TEMPS AOB GUIDANCE FOR INLAND PORTIONS OF CNTRL UPR MI. .LONG TERM (SUNDAY NIGHT THROUGH NEXT SATURDAY)... MAIN FORECAST CONCERN IS MODERATE TO HEAVY PERIOD OF SNOW SUNDAY NIGHT INTO MONDAY. SUNDAY NIGHT...SHRTWV TROUGH EXTENDING FROM WASHINGTON INTO CALIFORNIA IS PROGGED TO BE LOCATED OVER THE PLAINS AT 00Z. SINCE FAIRLY STRONG UPPER LEVEL RIDGING IS EXPECTED AHEAD OF THE TROUGH OVER THE EAST COAST...THIS TROUGH WILL HAVE TO LIFT NORTHEAST TOWARDS THE CWA. BY 12Z...THE TROUGH SHOULD BE LOCATED IN WESTERN WISCONSIN. THE TRACK OF THE TROUGH ALSO ALLOWS FOR A 100KT JET STREAK...WHICH SHOULD BE JUST SOUTH OF OMAHA AT 00Z MON...TO TRACK UP TO SAULT SAINTE MARIE BY 12Z...PLACING MUCH OF THE CWA IN THE LEFT EXIT REGION (FAVORED FOR UPPER LEVEL DIVERGENCE). IN ADDITION TO THE FAVORABLE UPPER JET TRACK...NAM/GFS SHOW DECENT MID-LEVEL FRONTOGENESIS MOVING THROUGH...ADDING EXTRA VERTICAL MOTION. OTHER THAN FOR SOME INITIAL DRY AIR...PARTICULARLY OVER THE EASTERN CWA...CONDITIONS LOOK FAVORABLE FOR BRINGING PRECIPITATION ACROSS MUCH OF THE CWA BY 12Z. SINCE MODELS HAVE BEEN SHOWING THIS FEATURE FOR A WHILE...HAVE RAISED POPS TO CATEGORICAL. MOST TEMPERATURE PROFILES ON SOUNDINGS WHEN THE PRECIPITATION IS MOVING THROUGH IS ALL BELOW FREEZING...EXCEPT IMMEDIATELY ALONG LAKE MICHIGAN... THEREFORE MAINLY SNOW IS EXPECTED. AS FOR AMOUNTS...GIVEN THE STRONG VERTICAL MOTION...AT LEAST A 0.25 INCH OF LIQUID SHOULD BE POSSIBLE. BECAUSE OF THE SYNOPTIC NATURE OF THE SYSTEM...A 10 TO 1 SNOWFALL RATIO WOULD BE APPROPRIATE...HOWEVER WITH THE SATURATED SNOW GROWTH LAYER A FEW THOUSAND FEET DEEP AND PLENTY OF VERTICAL MOTION IN THAT LAYER...WILL USE A 15 TO 1 RATIO TO ACCOUNT FOR MORE SNOWFALL. ADVISORIES MAY BE NEEDED FOR THIS EVENT IF SLIGHTLY MORE QPF OCCURS THAN EXPECTED. MONDAY...SHRTWV TROUGH WILL CONTINUE MOVING NORTHEASTWARD...CROSSING MOST OF THE CWA BY 00Z. IN FACT...SOME WEAK UPPER LEVEL RIDGING IS PROGGED TO BUILD INTO FAR WESTERN LAKE SUPERIOR BY 00Z AHEAD OF TROUGHING DEVELOPING OVER THE NW U.S.. EXPECT THE BAND OF FRONTOGENETIC SNOWFALL TO PROGRESS EASTWARD ACROSS THE CWA WITH THE SHRTWV TROUGH...AND SKIES GRADUALLY CLEARING OUT BEHIND IT. WITH 850MB TEMPS RISING TO AROUND -2C BY THE END OF THE DAY...TEMPERATURES SHOULD STILL BE ABLE TO HIT THE UPPER 30S/LOW 40S. MONDAY NIGHT...UPPER LEVEL RIDGING IS PROGGED TO ENCOMPASS THE CWA THROUGH THE NIGHT WHILE THE TROUGHING OVER THE NW MOVES TOWARDS THE PLAINS. SKIES SHOULD CLEAR OUT ACROSS MUCH OF THE CWA DURING THE EVENING DUE TO A COMBINATION OF DRY AIR ADVECTION...MID/UPPER LEVEL SUBSIDENCE AND LOW LEVEL ANTICYCLONIC FLOW FROM A HIGH PRESSURE RIDGE MOVING ACROSS. THESE FACTORS WILL ALLOW TEMPERATURES TO DROP FAIRLY QUICKLY. BY 12Z...THE SURFACE HIGH PRESSURE RIDGE IS PROGGED OVER THE EASTERN CWA...ALLOWING RETURN FLOW TO SET UP IN THE WESTERN U.P.. THEREFORE THIS AREA COULD SEE RISING TEMPERATURES AFTER MIDNIGHT. IN ADDITION...HIGH CLOUDS ARE EXPECTED TO INCREASE ACROSS THE CWA AFTER MIDNIGHT AS THE UPPER LEVEL RIDGE MOVES SLIGHTLY EASTWARD...WHICH SHOULD KEEP TEMPERATURES FROM DROPPING TOO LOW. STILL WENT CLOSE TO COOP GUIDANCE...THOUGH...GIVEN THE AMOUNT OF GOOD RADIATIONAL COOLING. TUESDAY...AN UPPER LEVEL TROUGH IS EXPECTED TO COVER MUCH OF THE PLAINS STATES BY 00Z WED...SIMILAR TO THAT OF 00Z MON BUT DEEPER. GFS/ECMWF INDICATE THAT A WEAK SHRTWV MAY MOVE ACROSS THE CWA DURING THE DAY. HOWEVER...RH PROFILES ARE VERY DRY...SO LIKELY THE MAIN IMPACT FROM THIS SHRTWV WILL BE FOR INCREASING MID/HIGH CLOUDS. ANOTHER SHRTWV IS PROGGED TO APPROACH THE WESTERN U.P. LATE IN THE DAY. THIS SHRTWV WILL BE ASSOCIATED WITH MORE ISENTROPIC LIFT AND MOISTURE...SO HAVE MAINTAINED A CHANCE OF RAIN/SNOW THERE. AS FAR AS TEMPERATURES GO...WITH QUITE A BIT OF CLOUD COVER EXPECTED...HAVE STAYED CLOSER TO MAV GUIDANCE. TUESDAY NIGHT THROUGH SATURDAY...OPERATIONAL MODELS ARE IN FAIRLY GOOD AGREEMENT REGARDING THE MOVEMENT OF THE UPPER LEVEL TROUGH...TAKING IT FROM THE PLAINS TUESDAY EVENING TO THE OHIO VALLEY BY THURSDAY MORNING...AND THEN INTO THE NORTHEAST U.S. ON FRIDAY. THE 12Z UKMET IS SLIGHTLY SLOWER IN THE MOTION OF THIS TROUGH COMPARED TO THE 12Z ECMWF/GFS...BUT GIVEN THE GOOD AGREEMENT...THIS SPEED DIFFERENCE IS NOT A BIG ISSUE. AS FAR AS THE TROUGH\S IMPACTS ON THE CWA\S WEATHER...ISENTROPIC LIFT AND HEIGHT FALLS AHEAD OF THE TROUGH MAY BRING SOME LIGHT SNOW OR RAIN INTO THE CWA TUESDAY NIGHT INTO WEDNESDAY. AS COLD AIR FLOWS IN BEHIND THE TROUGH ON WEDNESDAY NIGHT...THE PRECIPITATION SHOULD CHANGE OVER TO ALL SNOW. HOWEVER...THE AMOUNT OF COLD AIR IS NOT THAT SIGNIFICANT...WITH THE GFS (WHICH TYPICALLY HAS A COLD BIAS OUT IN THE EXTENDED) INDICATING 850MB TEMPS OF -2 TO -4C AT 12Z THU. SINCE LAKE SUPERIOR WATER TEMPERATURES ARE ONLY AROUND 6C...NO LAKE EFFECT IS EXPECTED. AS THE UPPER TROUGH LIFTS NORTHEASTWARD TOWARDS THE NORTHEAST U.S. THURSDAY...WARMER ATLANTIC AIR WRAPS BACK TOWARDS UPPER MICHIGAN. THEREFORE HAVE INCLUDED A MIX WITH RAIN AGAIN FOR THURSDAY ACROSS THE U.P....THEN ACROSS THE EASTERN CWA THURSDAY NIGHT. UPPER LEVEL FLOW FOR FRIDAY INTO SATURDAY IS EXPECTED TO BECOME WEST-NORTHWESTERLY...WHICH FAVORS FAST MOVING SHRTWVS TO SLIDE THROUGH UPPER MICHIGAN. ONE OF THESE SHRTWVS THE GFS/ECMWF SHOW MOVING THROUGH LATE FRIDAY INTO FRIDAY NIGHT. HAVE INCLUDED A SLIGHT CHANCE OF RAIN/SNOW WITH THIS FEATURE. THE 12Z ECMWF/GFS INDICATE THAT THE 850MB TEMPS WILL FALL TO AROUND -8C BEHIND THE SHRTWV EARLY SATURDAY MORNING OVER EASTERN LAKE SUPERIOR...THEN WARM QUICKLY THROUGH THE DAY. THEREFORE THERE MIGHT BE A BRIEF PERIOD OF LAKE EFFECT...BUT FOR NOW PREFER TO LEAVE SATURDAY DRY WITH THE THINKING THAT MUCH OF THE LAKE EFFECT WILL OCCUR FRIDAY NIGHT...IF ANY. TEMPERATURES THROUGH THE EXTENDED SHOULD REMAIN AT OR JUST SLIGHTLY ABOVE NORMAL GIVEN RELATIVELY MILD 850MB TEMPS THROUGH THE PERIOD. LOOKING OUT BEYOND SATURDAY INTO THE WEEK AFTER...PATTERN LOOKS NEARLY ZONAL WHICH FAVORS CONTINUED PACIFIC AIRMASSES. THEREFORE TEMPERATURES SHOULD STAY NEAR OR ABOVE NORMAL. && .MQT WATCHES/WARNINGS/ADVISORIES...NONE. && $$ JLB (SHORT TERM) AJ (LONG TERM) mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1256 PM EST SAT NOV 11 2006 .AVIATION... TOUGH CALL ON THE EXACT TIMING OF MVFR CLOUD DISSIPATION TONIGHT...BUT VERY DRY AIR AND LARGE SCALE SUBSIDENCE SHOULD WIN OUT SOONER RATHER THAN LATER. THEREFORE...CEILINGS ARE EXPECTED TO LIFT ABOVE 3K FEET BY MIDNIGHT...WITH STRATOCUMULUS CLOUDS BECOMING SCATTERED DURING THE EARLY MORNING HOURS. THIS WILL ALL BE DRIVEN BY RIDGING THAT WILL QUICKLY REPLACE THE TROUGHINESS CURRENTLY OVER THE REGION. 500 MB HEIGHTS WILL RISE QUICKLY BEGINNING EARLY THIS EVENING...RESULTING IN STRONG SUBSIDENCE AND A DRYING ATMOSPHERE. THE THINKING IS THAT THE WINDS WILL REMAIN UP JUST ENOUGH TO PRECLUDE ANY FOG DEVELOPMENT OVERNIGHT. HOWEVER...IF WE CLEAR OUT COMPLETELY AND WINDS GO NEARLY CALM...WE MAY HAVE SOME PATCHY FOG FOR A BRIEF PERIOD OF TIME AROUND SUNRISE. AT THIS TIME...NOT ENOUGH CONFIDENCE EXISTS TO INCLUDE IN TAFS. && .PREV DISCUSSION...ISSUED 1112 AM EST SAT NOV 11 2006 UPDATE... SURFACE OBS/RUC ANALYSIS/SATELLITE AND RADAR IMAGERY ALL DEPICT A WEAKENING STORM SYSTEM. THE SURFACE LOW RAPIDLY MOVED EAST OF OUR AREA THIS MORNING AND THE CENTRAL PRESSURE CONTINUES TO CLIMB. LATEST RUC DATA INDICATES RISING HEIGHTS ASSOCIATED WITH THE MID AND UPPER LEVEL WAVES NOW MOVING ACROSS WESTERN MICHIGAN. WATER VAPOR IMAGERY CONTINUES TO SHOW A DRY SLOT POSITIONED ACROSS SOUTHEAST LOWER MICHIGAN AND A WEDGE OF MOISTURE ALONG THE MID/UPPER LEVEL TROUGH AXIS SLOWLY PIVOTING TO THE EAST ACROSS LAKE MICHIGAN. WATER VAPOR DEPICTS THIS WEDGE OF MOISTURE STEADILY DISSIPATING...SUPPORTING AN OVERALL WEAKENING TO THIS SYSTEM. OUTSIDE OF A VERY BRIEF PERIOD OF A RAIN AND SNOW MIX AT A FEW LOCATIONS ACROSS THE NORTHERN COUNTIES AROUND SUNRISE...ALL PRECIPITATION HAS BEEN IN THE FORM OF RAIN. RADAR COVERAGE AND RETURNS SUPPORT A CONTINUED WEAKENING TREND WITH A BAND OF LIGHT DRIZZLE (AS SUPPORTED BY OBS) STRETCHING ACROSS PART OF THE CWA WITHIN AN AREA OF WEAKENING DEFORMATION. TEMPERATURES HAVE RISEN A FEW DEGREES AT MOST SITES ACROSS THE CWA THIS MORNING. MOST SITES ARE CURRENTLY IN THE UPPER 30'S...TO THE LOW 40'S ACROSS THE SOUTHERN COUNTIES. DEWPOINTS ARE ALSO WELL ABOVE FREEZING. MID LEVELS WILL CONTINUE TO COOL THIS AFTERNOON...BUT AT THE SAME TIME...MUCH DRIER AIR WILL ADVECT INTO THE AREA. SHALLOW MOIST BOUNDARY LAYER WILL BECOME MORE UNSTABLE BUT LACK ENOUGH SUPPORT FOR PRECIPITATION AT THE SURFACE. ZONES WERE UPDATED TO REFLECT THESE CHANGES...WITH SCATTERED LIGHT RAIN SHOWERS EXPECTED TO DISSIPATE BY MID AFTERNOON AS DEFORMATION CONTINUES TO WEAKEN AND DRIER AIR TAKES OVER. PREV DISCUSSION...ISSUED 657 AM EST SAT NOV 11 2006 AVIATION... LOTS OF IFR CONDITIONS ACROSS FORECAST AREA THROUGH EARLY MORNING REFLECTED IN TAFS...AND MAINLY DUE TO CEILINGS...WITH TEMPO GROUPS OF LIGHT SHOWERS OF RAIN KDTW/KDET AND OF RAIN OR MIX AT KFNT/KMBS IN RESPONSE TO INCREASING EXTENT OF SHOWERS HAVING DEVELOPED IN DRY SLOT. TAFS REFLECT SLIGHTLY IMPROVED CEILINGS/MVFR CONDITIONS BY LATE MORNING AND CONTINUING THROUGH THE TAF PERIOD. EXPECT FAIRLY WIDESPREAD LIGHT MIX OF RAIN AND SNOW SHOWERS...THOUGH...AT KDTW/DET THIS AFTERNOON AND FLURRIES/LIGHT SNOW SHOWERS AT KFNT/KMBS AS WEAK DEFORMATION SLIDES EAST ACROSS THE AREA. MODEL SOUNDINGS SHOW LOW MOISTURE TRAPPED BENEATH STRONG INVERSION TONIGHT WILL MAKE IT DIFFICULT TO BREAK THE CEILINGS. PREV DISCUSSION...ISSUED 405 AM EST SAT NOV 11 2006 SHORT TERM...TODAY AND TONIGHT SURFACE LOW AS OF 08Z HAD ALREADY REACHED CENTRAL LAKE ERIE...WELL AHEAD OF PACE OF MOST 00Z RUNS AND CERTAINLY WELL AHEAD OF PACE SHOWN BY MODELS 24 HOURS AGO. THIS LOW IS EXPECTED TO CONTINUE TO RETREAT AND REDEVELOP SOUTHEAST TODAY LEAVING BRISK NORTHERLY FLOW IN ITS WAKE...THEN A RIDGE SLOWLY BUILDS IN TONIGHT. AT 500 MB...A SHARPENING TROUGH STILL TO MOVE ACROSS THE FORECAST AREA THIS AFTERNOON/EVENING...THOUGH MAIN VORTICITY ENERGY WILL BE WELL TO THE SOUTH IN BASE OF TROUGH...WITH SHORTWAVE RIDGE BUILDING IN LATE TONIGHT. NOT A LOT OF CONFIDENCE IN DETAILS OF MODELS...GIVEN RECENT PERFORMANCE. WATER VAPOR/SATELLITE IMAGERY CONTINUES TO SHOW BAROCLINIC ZONE EASING ITS WAY EAST OUT OF LOWER MICHIGAN...WITH A RATHER PRONOUNCED DRY SLOT SPREADING ACROSS LOWER MICHIGAN BEHIND IT. MODELS ARE TENDING TO UNDERPLAY THIS DRY WEDGE...THOUGH MORE MOISTURE IS EXPECTED TO WRAP BACK INTO AREA THIS AFTERNOON BEHIND DRY SLOT. MEANWHILE...MODELS IN GOOD AGREEMENT DEPICTING RICH 925 MB MOISTURE UNTIL IT BEGINS TO EASE LATE TONIGHT. MODELS STILL SHOW SOME RESIDUAL...ALBEIT MAINLY WEAK...LOW TO MID LEVEL OMEGA ASCENT TODAY...WITH MORE IN WAY OF SUBSIDENCE TONIGHT. 850 TO 500 MB QVECTOR CONVERGENCE STILL MODEST TODAY AS WELL...ALONG WITH A BIT OF 250 MB DIVERGENCE/850 MB CONVERGENCE COUPLING. ALSO... LOW TO MID LEVEL FRONTOGENESIS LINGERING MAINLY SOUTHEAST TODAY...WHILE WEAK AREA OF DEFORMATION IS EXPECTED TO SLIDE ACROSS SOUTHEAST MI TODAY. IN LIGHT OF DRY SLOT AND CURRENT RADAR TRENDS...WILL MENTION ONLY SCATTERED LIGHT PRECIPITATION THIS MORNING. THEN...WITH BETTER MOISTURE AND STILL SOME DYNAMICS THIS AFTERNOON...WILL GO NUMEROUS POPS EXCEPT SCATTERED IN SAGINAW VALLEY. AS FOR PRECIPITATION TYPE...AM STARTING OFF AS MIX IN NORTH AND LIQUID CENTRAL AND SOUTH...TRANSITIONING TO SNOW FROM NORTHWEST TO SOUTHEAST AS THE DAY UNFOLDS. SNOW AMOUNTS TODAY AN INCH OR LESS. WILL KEEP EVENING FLURRY MENTION FOR NOW...THOUGH ICE NUCLEATION MAY BECOME DIFFICULT EARLIER. AM LEAVING HEADLINES INTACT FOR MARINE AREAS. GFS IS STILL GOING FOR 925 MB WINDS AROUND 35 KNOTS TODAY IN THE VICINITY OF SOUTHERN LAKE HURON. LONG TERM...SUNDAY THROUGH FRIDAY SAME METEOROLOGICAL THINKING APPLIES THIS MORNING FROM PREVIOUS FORECASTS AS POTENT PACIFIC JET (ANALYZED NEAR 200KTS PER SATELLITE DERIVED INFO) WILL PLAQUE THE WEATHER ACROSS THE CONUS THIS UPCOMING WEEK. STILL SEVERAL MODELS POINTING TOWARD A STRONG STORM SYSTEM TO IMPACT THE REGION MID-WEEK BUT NO MAJOR ARCTIC INTRUSIONS EXPECTED. SUNDAY... SURFACE HIGH AND UPPER RIDGE AXIS WILL BE OVER THE GREAT LAKES WITH VERY DRY FORECAST SOUNDINGS. HOWEVER...SOME HINT OF LOW LEVEL MOISTURE BUT THIS DOES SEEM SHALLOW AND THOUGHTS ARE TOWARD A MOSTLY SUNNY DAY. WITH MINIMAL MIXING EXPECTED...STILL KEEP HIGH TEMPERATURES GENERALLY BETWEEN 41-46 DEGREES. SUNDAY NIGHT... AS OBSERVED IN THE WATER VAPOR IMAGERY THIS MORNING...PACIFIC SHORT WAVE COMING ASHORE ACROSS THE WEST COAST OF THE CONUS RACES TOWARD THE PLAINS. THIS WILL AID THE SURFACE COLD FRONT TO APPROACH THE WESTERN LAKES OVERNIGHT. MOISTURE APPEARS LIMITED AND QUITE NARROW WHICH COMES INTO THE LOCAL AREA MONDAY. CLOUDS SHOULD BE SLOW TO INCREASE DUE TO THE AFOREMENTIONED LACK OF MOISTURE SO RADIATIONAL COOLING (AT OR A FEW DEGREES BELOW FREEZING...NEAR MAV NUMBERS) SHOULD COMMENCE EARLY BEFORE SOME OF THIS CLOUD COVER MOVES INTO THE AREA OVERNIGHT. MONDAY AND MONDAY NIGHT... FAST MOVING COOL FRONT...SHORT WAVE TROF AND ENTRANCE REGION OF UPPER JET WILL BE IN PLACE MONDAY AFTERNOON. DPROG/DT OF THE MODEL FIELDS SUGGEST QPF WILL DECREASE WITH MINIMAL MOISTURE TRANSPORT AND GULF ALL BUT SHUT OFF TO THIS SYSTEM. THEREFORE POPS WILL BE DECREASED ANOTHER 10% AND WILL RETAIN THE CHANCE/SLIGHT CHANCE FOR THE CWA. LOCATIONS SOUTH OF M59 HAVE A GOOD SHOT OF REMAINING DRY BEFORE NEXT SURFACE HIGH AND A DRY COLUMN OF AIR (850-500MB RH OF <=20%) MOVE IN THE REGION MONDAY NIGHT. TUESDAY THROUGH THURSDAY... MODEL CONSENSUS FOR THE MID WEEK FAVORS A WET PATTERN FOR THE GREAT LAKES ALTHOUGH DETAILS REMAIN IFFY. THE UKMET/GFS/ECMWF/18Z-DGEX SUGGEST POTENT PACIFIC JET WILL DIVE SOUTHEAST FROM THE PACIFIC NORTHWEST INTO THE SOUTH CENTRAL PLAINS WITH SURFACE CYCLOGENESIS ACROSS THE MID MISSISSIPPI RIVER VALLEY TUESDAY NIGHT INTO WEDNESDAY AS UPPER PATTERN BECOME MORE NEGATIVELY TILTED TOWARD THE GREAT LAKES. THE LOCAL WRF-HEMI SUGGESTS A RATHER MORE PROGRESSIVE NATURE TO THIS SYSTEM WHICH IS AN OUTLIER BUT IT DOES HAVE SOME SUPPORT FROM THE RECENTLY UPGRADED CANADIAN GLOBAL. THE ECMWF IS NEARLY IDENTICAL TO THE 18Z-DGEX AND WHEN BLENDING THESE MODEL SOLUTIONS TO THE LOCAL WRF-HEMI SUGGESTS A WEAKER SURFACE REFLECTION BUT UPPER PATTERN DOES AMPLIFY BUT LIKELY NOT TO THE EXTENT OF THE GFS. SENSIBLE WEATHER FOR THE GREAT LAKES DOES NOT CHANGE IN THE CURRENT FORECAST WITH RAIN CHANCES INCREASING TUESDAY NIGHT INTO WEDNESDAY. ELEVATED INSTABILITY IS EXPECTED TO INCREASE WITH SHOWALTERS DROPPING BACK TOWARD 0C AND WILL ADD THE SLIGHT CHANCE FOR THUNDER. COOLER AIR ARRIVES THURSDAY WITH THE CHANCE FOR SOME RAIN/SNOW SHOWERS. AGAIN...NO MAJOR ARCTIC OUTBREAKS WITH THE PACIFIC ZONAL INFLUENCE KEEPING THE COLDER AIR LOCKED UP TO OUR NORTH. FRIDAY... IT SEEMS WE REMAIN WITHIN A REGION OF BAROCLINICITY WITH A NEAR ZONAL FLOW ACROSS THE NORTHERN HALF OF THE CONUS (MORE LIKE AN EL NINO PATTERN WITH LATEST SST ANALYSIS INDICATING EASTERN PACIFIC TEMPS A GOOD 1-3 DEGREES ABOVE CLIMATOLOGY). REMNANTS OF MID WEEK SYSTEM LIFT NORTH WITH A SLIGHT MODIFICATION TO THE THERMAL PROFILE BUT SUNSHINE COULD BE AT A PREMIUM. AT THIS TIME THE CURRENT IDEA OF PTSUNNY SKIES AND TEMPERATURES AVERAGING NEAR OR SLIGHTLY BELOW NORMAL. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...GALE WARNING...LHZ421...NEARSHORE WATERS FROM PORT AUSTIN TO PORT H UNTIL 1 AM SUNDAY. GALE WARNING...LHZ422 UNTIL 10 PM SATURDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY...LCZ422-LCZ460 UNTIL 1 AM SUNDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...LEZ444 UNTIL 1 AM SUNDAY. && $$ AVIATION/UPDATE...SHULER SHORT TERM...DWD LONG TERM....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 1112 AM EST SAT NOV 11 2006 .UPDATE... SURFACE OBS/RUC ANALYSIS/SATELLITE AND RADAR IMAGERY ALL DEPICT A WEAKENING STORM SYSTEM. THE SURFACE LOW RAPIDLY MOVED EAST OF OUR AREA THIS MORNING AND THE CENTRAL PRESSURE CONTINUES TO CLIMB. LATEST RUC DATA INDICATES RISING HEIGHTS ASSOCIATED WITH THE MID AND UPPER LEVEL WAVES NOW MOVING ACROSS WESTERN MICHIGAN. WATER VAPOR IMAGERY CONTINUES TO SHOW A DRY SLOT POSITIONED ACROSS SOUTHEAST LOWER MICHIGAN AND A WEDGE OF MOISTURE ALONG THE MID/UPPER LEVEL TROUGH AXIS SLOWLY PIVOTING TO THE EAST ACROSS LAKE MICHIGAN. WATER VAPOR DEPICTS THIS WEDGE OF MOISTURE STEADILY DISSIPATING...SUPPORTING AN OVERALL WEAKENING TO THIS SYSTEM. OUTSIDE OF A VERY BRIEF PERIOD OF A RAIN AND SNOW MIX AT A FEW LOCATIONS ACROSS THE NORTHERN COUNTIES AROUND SUNRISE...ALL PRECIPITATION HAS BEEN IN THE FORM OF RAIN. RADAR COVERAGE AND RETURNS SUPPORT A CONTINUED WEAKENING TREND WITH A BAND OF LIGHT DRIZZLE (AS SUPPORTED BY OBS) STRETCHING ACROSS PART OF THE CWA WITHIN AN AREA OF WEAKENING DEFORMATION. TEMPERATURES HAVE RISEN A FEW DEGREES AT MOST SITES ACROSS THE CWA THIS MORNING. MOST SITES ARE CURRENTLY IN THE UPPER 30'S...TO THE LOW 40'S ACROSS THE SOUTHERN COUNTIES. DEWPOINTS ARE ALSO WELL ABOVE FREEZING. MID LEVELS WILL CONTINUE TO COOL THIS AFTERNOON...BUT AT THE SAME TIME...MUCH DRIER AIR WILL ADVECT INTO THE AREA. SHALLOW MOIST BOUNDARY LAYER WILL BECOME MORE UNSTABLE BUT LACK ENOUGH SUPPORT FOR PRECIPITATION AT THE SURFACE. ZONES WERE UPDATED TO REFLECT THESE CHANGES...WITH SCATTERED LIGHT RAIN SHOWERS EXPECTED TO DISSIPATE BY MID AFTERNOON AS DEFORMATION CONTINUES TO WEAKEN AND DRIER AIR TAKES OVER. && PREV DISCUSSION...ISSUED 657 AM EST SAT NOV 11 2006 AVIATION... LOTS OF IFR CONDITIONS ACROSS FORECAST AREA THROUGH EARLY MORNING REFLECTED IN TAFS...AND MAINLY DUE TO CEILINGS...WITH TEMPO GROUPS OF LIGHT SHOWERS OF RAIN KDTW/KDET AND OF RAIN OR MIX AT KFNT/KMBS IN RESPONSE TO INCREASING EXTENT OF SHOWERS HAVING DEVELOPED IN DRY SLOT. TAFS REFLECT SLIGHTLY IMPROVED CEILINGS/MVFR CONDITIONS BY LATE MORNING AND CONTINUING THROUGH THE TAF PERIOD. EXPECT FAIRLY WIDESPREAD LIGHT MIX OF RAIN AND SNOW SHOWERS...THOUGH...AT KDTW/DET THIS AFTERNOON AND FLURRIES/LIGHT SNOW SHOWERS AT KFNT/KMBS AS WEAK DEFORMATION SLIDES EAST ACROSS THE AREA. MODEL SOUNDINGS SHOW LOW MOISTURE TRAPPED BENEATH STRONG INVERSION TONIGHT WILL MAKE IT DIFFICULT TO BREAK THE CEILINGS. PREV DISCUSSION...ISSUED 405 AM EST SAT NOV 11 2006 SHORT TERM...TODAY AND TONIGHT SURFACE LOW AS OF 08Z HAD ALREADY REACHED CENTRAL LAKE ERIE...WELL AHEAD OF PACE OF MOST 00Z RUNS AND CERTAINLY WELL AHEAD OF PACE SHOWN BY MODELS 24 HOURS AGO. THIS LOW IS EXPECTED TO CONTINUE TO RETREAT AND REDEVELOP SOUTHEAST TODAY LEAVING BRISK NORTHERLY FLOW IN ITS WAKE...THEN A RIDGE SLOWLY BUILDS IN TONIGHT. AT 500 MB...A SHARPENING TROUGH STILL TO MOVE ACROSS THE FORECAST AREA THIS AFTERNOON/EVENING...THOUGH MAIN VORTICITY ENERGY WILL BE WELL TO THE SOUTH IN BASE OF TROUGH...WITH SHORTWAVE RIDGE BUILDING IN LATE TONIGHT. NOT A LOT OF CONFIDENCE IN DETAILS OF MODELS...GIVEN RECENT PERFORMANCE. WATER VAPOR/SATELLITE IMAGERY CONTINUES TO SHOW BAROCLINIC ZONE EASING ITS WAY EAST OUT OF LOWER MICHIGAN...WITH A RATHER PRONOUNCED DRY SLOT SPREADING ACROSS LOWER MICHIGAN BEHIND IT. MODELS ARE TENDING TO UNDERPLAY THIS DRY WEDGE...THOUGH MORE MOISTURE IS EXPECTED TO WRAP BACK INTO AREA THIS AFTERNOON BEHIND DRY SLOT. MEANWHILE...MODELS IN GOOD AGREEMENT DEPICTING RICH 925 MB MOISTURE UNTIL IT BEGINS TO EASE LATE TONIGHT. MODELS STILL SHOW SOME RESIDUAL...ALBEIT MAINLY WEAK...LOW TO MID LEVEL OMEGA ASCENT TODAY...WITH MORE IN WAY OF SUBSIDENCE TONIGHT. 850 TO 500 MB QVECTOR CONVERGENCE STILL MODEST TODAY AS WELL...ALONG WITH A BIT OF 250 MB DIVERGENCE/850 MB CONVERGENCE COUPLING. ALSO... LOW TO MID LEVEL FRONTOGENESIS LINGERING MAINLY SOUTHEAST TODAY...WHILE WEAK AREA OF DEFORMATION IS EXPECTED TO SLIDE ACROSS SOUTHEAST MI TODAY. IN LIGHT OF DRY SLOT AND CURRENT RADAR TRENDS...WILL MENTION ONLY SCATTERED LIGHT PRECIPITATION THIS MORNING. THEN...WITH BETTER MOISTURE AND STILL SOME DYNAMICS THIS AFTERNOON...WILL GO NUMEROUS POPS EXCEPT SCATTERED IN SAGINAW VALLEY. AS FOR PRECIPITATION TYPE...AM STARTING OFF AS MIX IN NORTH AND LIQUID CENTRAL AND SOUTH...TRANSITIONING TO SNOW FROM NORTHWEST TO SOUTHEAST AS THE DAY UNFOLDS. SNOW AMOUNTS TODAY AN INCH OR LESS. WILL KEEP EVENING FLURRY MENTION FOR NOW...THOUGH ICE NUCLEATION MAY BECOME DIFFICULT EARLIER. AM LEAVING HEADLINES INTACT FOR MARINE AREAS. GFS IS STILL GOING FOR 925 MB WINDS AROUND 35 KNOTS TODAY IN THE VICINITY OF SOUTHERN LAKE HURON. LONG TERM...SUNDAY THROUGH FRIDAY SAME METEOROLOGICAL THINKING APPLIES THIS MORNING FROM PREVIOUS FORECASTS AS POTENT PACIFIC JET (ANALYZED NEAR 200KTS PER SATELLITE DERIVED INFO) WILL PLAQUE THE WEATHER ACROSS THE CONUS THIS UPCOMING WEEK. STILL SEVERAL MODELS POINTING TOWARD A STRONG STORM SYSTEM TO IMPACT THE REGION MID-WEEK BUT NO MAJOR ARCTIC INTRUSIONS EXPECTED. SUNDAY... SURFACE HIGH AND UPPER RIDGE AXIS WILL BE OVER THE GREAT LAKES WITH VERY DRY FORECAST SOUNDINGS. HOWEVER...SOME HINT OF LOW LEVEL MOISTURE BUT THIS DOES SEEM SHALLOW AND THOUGHTS ARE TOWARD A MOSTLY SUNNY DAY. WITH MINIMAL MIXING EXPECTED...STILL KEEP HIGH TEMPERATURES GENERALLY BETWEEN 41-46 DEGREES. SUNDAY NIGHT... AS OBSERVED IN THE WATER VAPOR IMAGERY THIS MORNING...PACIFIC SHORT WAVE COMING ASHORE ACROSS THE WEST COAST OF THE CONUS RACES TOWARD THE PLAINS. THIS WILL AID THE SURFACE COLD FRONT TO APPROACH THE WESTERN LAKES OVERNIGHT. MOISTURE APPEARS LIMITED AND QUITE NARROW WHICH COMES INTO THE LOCAL AREA MONDAY. CLOUDS SHOULD BE SLOW TO INCREASE DUE TO THE AFOREMENTIONED LACK OF MOISTURE SO RADIATIONAL COOLING (AT OR A FEW DEGREES BELOW FREEZING...NEAR MAV NUMBERS) SHOULD COMMENCE EARLY BEFORE SOME OF THIS CLOUD COVER MOVES INTO THE AREA OVERNIGHT. MONDAY AND MONDAY NIGHT... FAST MOVING COOL FRONT...SHORT WAVE TROF AND ENTRANCE REGION OF UPPER JET WILL BE IN PLACE MONDAY AFTERNOON. DPROG/DT OF THE MODEL FIELDS SUGGEST QPF WILL DECREASE WITH MINIMAL MOISTURE TRANSPORT AND GULF ALL BUT SHUT OFF TO THIS SYSTEM. THEREFORE POPS WILL BE DECREASED ANOTHER 10% AND WILL RETAIN THE CHANCE/SLIGHT CHANCE FOR THE CWA. LOCATIONS SOUTH OF M59 HAVE A GOOD SHOT OF REMAINING DRY BEFORE NEXT SURFACE HIGH AND A DRY COLUMN OF AIR (850-500MB RH OF <=20%) MOVE IN THE REGION MONDAY NIGHT. TUESDAY THROUGH THURSDAY... MODEL CONSENSUS FOR THE MID WEEK FAVORS A WET PATTERN FOR THE GREAT LAKES ALTHOUGH DETAILS REMAIN IFFY. THE UKMET/GFS/ECMWF/18Z-DGEX SUGGEST POTENT PACIFIC JET WILL DIVE SOUTHEAST FROM THE PACIFIC NORTHWEST INTO THE SOUTH CENTRAL PLAINS WITH SURFACE CYCLOGENESIS ACROSS THE MID MISSISSIPPI RIVER VALLEY TUESDAY NIGHT INTO WEDNESDAY AS UPPER PATTERN BECOME MORE NEGATIVELY TILTED TOWARD THE GREAT LAKES. THE LOCAL WRF-HEMI SUGGESTS A RATHER MORE PROGRESSIVE NATURE TO THIS SYSTEM WHICH IS AN OUTLIER BUT IT DOES HAVE SOME SUPPORT FROM THE RECENTLY UPGRADED CANADIAN GLOBAL. THE ECMWF IS NEARLY IDENTICAL TO THE 18Z-DGEX AND WHEN BLENDING THESE MODEL SOLUTIONS TO THE LOCAL WRF-HEMI SUGGESTS A WEAKER SURFACE REFLECTION BUT UPPER PATTERN DOES AMPLIFY BUT LIKELY NOT TO THE EXTENT OF THE GFS. SENSIBLE WEATHER FOR THE GREAT LAKES DOES NOT CHANGE IN THE CURRENT FORECAST WITH RAIN CHANCES INCREASING TUESDAY NIGHT INTO WEDNESDAY. ELEVATED INSTABILITY IS EXPECTED TO INCREASE WITH SHOWALTERS DROPPING BACK TOWARD 0C AND WILL ADD THE SLIGHT CHANCE FOR THUNDER. COOLER AIR ARRIVES THURSDAY WITH THE CHANCE FOR SOME RAIN/SNOW SHOWERS. AGAIN...NO MAJOR ARCTIC OUTBREAKS WITH THE PACIFIC ZONAL INFLUENCE KEEPING THE COLDER AIR LOCKED UP TO OUR NORTH. FRIDAY... IT SEEMS WE REMAIN WITHIN A REGION OF BAROCLINICITY WITH A NEAR ZONAL FLOW ACROSS THE NORTHERN HALF OF THE CONUS (MORE LIKE AN EL NINO PATTERN WITH LATEST SST ANALYSIS INDICATING EASTERN PACIFIC TEMPS A GOOD 1-3 DEGREES ABOVE CLIMATOLOGY). REMNANTS OF MID WEEK SYSTEM LIFT NORTH WITH A SLIGHT MODIFICATION TO THE THERMAL PROFILE BUT SUNSHINE COULD BE AT A PREMIUM. AT THIS TIME THE CURRENT IDEA OF PTSUNNY SKIES AND TEMPERATURES AVERAGING NEAR OR SLIGHTLY BELOW NORMAL. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...GALE WARNING...LHZ421...NEARSHORE WATERS FROM PORT AUSTIN TO PORT H UNTIL 1 AM SUNDAY. GALE WARNING...LHZ422 UNTIL 10 PM SATURDAY. LAKE ST CLAIR...SMALL CRAFT ADVISORY...LCZ422-LCZ460 UNTIL 1 AM SUNDAY. MI WATERS OF LAKE ERIE...SMALL CRAFT ADVISORY...LEZ444 UNTIL 1 AM SUNDAY. && $$ UPDATE...SHULER SHORT TERM...DWD LONG TERM....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 BILLINGS MT 810 PM MST SAT NOV 11 2006 .SHORT TERM...VALID FOR SUN AND MON... WAVE CURRENTLY PUSHING THROUGH THE AREA HAS RESULTED IN SOME LIGHT RA/SN SHOWERS ACROSS OUR WEST/SOUTH THIS EVENING. AIRMASS COOLED QUICKLY BEHIND SFC FROPA EARLIER THIS EVENING...ALLOWING FOR A CHANGE TO SNOW ALONG THE FOOTHILLS...AND SOME LIGHT SNOW ACCUMULATION IS NOTED AT RED LODGE AS OF 0230Z. PCPN IS HEAVIEST ALONG THE SOUTHERN HIGHER TERRAIN PER THE POST FRONTAL NW FLOW. LOCATIONS TO THE NORTH AND EAST HAVE SEEN LITTLE MORE THAN SPRINKLES OR VIRGA DUE TO THE DRY LOW LEVELS. HAVE REDUCED EVENING POPS FROM BILLINGS NORTH/EAST TO JUST ISOLD...AND EVEN THIS IS PROBABLY TOO OPTIMISTIC GIVEN LATEST SATELLITE/RADAR TRENDS. HAVE RAISED POPS ALONG THE SOUTHERN FOOTHILLS...WHERE THEY SHOULD SEE UP TO AN INCH OF QUICK SNOW FROM NYE TO RED LODGE. THINGS WILL QUIET DOWN AFTER MIDNIGHT AS SFC RIDGE BUILDS IN FROM THE WEST...BUT WILL SUSTAIN HIGH ELEVATION POPS THRU 12Z AS COLDEST AIR ALOFT MOVES IN FROM THE WEST WITH A SECONDARY WEAK SHORTWAVE. GFS/RUC SHOW WEAK MID LEVEL Q-VECTOR CONVERGENCE PERSISTING THROUGH 12Z...ALONG WITH INCREASED INSTABILITY AS TEMPS ALOFT COOL. BIG HORNS SHOULD SEE A FEW INCHES IN UNSTABLE NW FLOW BUT WITH PROGRESSIVE NATURE OF WAVE THEY SHOULD EASILY REMAIN BELOW ADVISORY CRITERIA. CURRENT FORECAST LOOKS GOOD HERE. ALREADY TWEAKED GRIDS. UPDATED ZONES COMING SHORTLY. JKL .LONG TERM...VALID FOR TUE...WED...THU...FRI...SAT... ONLY MINOR CHANGES FOR THE EXTENDED FORECAST THIS AFTERNOON. WILL KEEP PRECIPITATION CHANCES AS INHERITED DUE TO LIFT ASSOCIATED WITH THE COLD FRONTAL PASSAGE TUESDAY. AFTER THIS ROUND OF PRECIPITATION SHIFTS EAST OF THE AREA TUESDAY NIGHT...THE NEXT JET STREAK WILL COME ASHORE IN WASHINGTON STATE AND INDUCE SURFACE PRESSURE FALLS ACROSS THE FORECAST AREA WEDNESDAY. WARM AIR ADVECTION ALOFT AS THIS TROUGH AND WARM FRONT SHIFT EAST WILL PRODUCE A SLIGHT CHANCE FOR RAIN SHOWERS ACROSS THE CENTRAL AND WESTERN ZONES WEDNESDAY. IN ADDITION...VERY FAST WESTERLY FLOW ASSOCIATED WITH THE JET STREAK WILL ENHANCE PRECIPITATION CHANCES IN THE MOUNTAIN AREAS...PARTICULARLY THE WEST FACING SLOPES. AS THE SURFACE LOW PASSES TO THE NORTH...PRESSURE GRADIENTS BETWEEN EASTERN IDAHO AND THE LEWISTOWN AREA ARE CURRENTLY FORECAST TO BE ENOUGH TO SUPPORT AT LEAST ADVISORY CRITERIA WINDS IN THE UPPER YELLOWSTONE AND UPPER STILLWATER VALLEYS. SINCE THIS IS STILL FOUR DAYS OUT IN THE FORECAST...HAVE ONLY ADJUSTED WIND SPEEDS UP IN THE GRIDS. WILL NEED TO WATCH THIS WEDNESDAY NIGHT PERIOD FOR POSSIBLE HIGH WIND WARNINGS IN THOSE AREAS. NO MAJOR CHANGES FOR PRECIPITATION CHANCES BEYOND THAT POINT IN THE FORECAST...KEEPING THE IDEA THAT THE FAST ZONAL WESTERLY FLOW WILL CONTINUE TO PRODUCE THE BEST CHANCES FOR PRECIPITATION IN THE MOUNTAIN AREAS...PARTICULARLY THE WEST FACING SLOPES. HAVE INCREASED TEMPERATURES SLIGHTLY FROM WEDNESDAY THROUGH SATURDAY NIGHT. LARGEST INCREASE TO LOW TEMPERATURES WAS FOR WEDNESDAY NIGHT WHEN STRONG WINDS ARE EXPECTED TO KEEP CONDITIONS QUITE WARM...ESPECIALLY IN THE FAVORED GAP WIND AND FOOTHILLS AREAS. HAVE ALSO INCREASED HIGH TEMPERATURES SLIGHTLY AS ZONAL FLOW YIELDS TO INCREASING HEIGHTS AHEAD OF A BROAD UPPER LEVEL LOW IN THE GULF OF ALASKA. CARPENTER && .AVIATION... A COLD FRONT WITH ASSOCIATED RAIN AND SNOW SHOWERS WILL PUSH SE THROUGH SE MT AND NORTH CENTRAL WY THROUGH 06Z. MVFR CONDITIONS WILL ACCOMPANY THE PRECIPITATION AND WILL MAINLY AFFECT AREAS E AND S OF KBIL. MOUNTAIN OBSCURATION WILL ALSO OCCUR IN THESE AREAS. VFR WILL PREVAIL ELSEWHERE. EXPECT VFR CONDITIONS OVER THE ROUTES SUN AND SUN EVENING. MOUNTAIN OBSCURATION WILL BE POSSIBLE OVER THE BEARTOOTH AND ABSAROKA MOUNTAINS SUN EVENING. ARTHUR && .PRELIMINARY POINT TEMP/POPS... SUN MON TUE WED THU FRI SAT ----------------------------------------------------------- BIL 030/045 028/049 031/043 027/047 035/052 032/051 031/050 20/B 02/O 13/O 02/R 02/R 22/O 00/B LVM 026/043 035/048 033/041 028/047 038/051 030/051 030/048 30/N 04/R 33/O 00/N 03/R 22/O 00/B HDN 029/046 026/050 028/043 027/048 036/054 029/052 029/052 30/B 02/O 14/O 02/R 02/R 22/R 00/B MLS 026/048 023/050 027/040 024/049 030/052 028/052 026/051 20/B 03/O 14/O 20/B 02/R 20/B 00/B 4BQ 026/043 023/048 027/041 024/049 031/051 029/051 027/051 20/B 03/O 34/O 20/B 00/B 20/B 00/B BHK 026/045 022/050 027/038 022/046 028/050 024/048 023/049 20/B 02/O 34/O 20/B 02/R 20/B 00/B SHR 027/041 014/049 029/043 021/048 026/053 024/051 024/052 60/B 02/O 34/O 20/B 00/B 22/O 00/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...NONE. WY...NONE. && $$ WEATHER.GOV/BILLINGS mt AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEWPORT/MOREHEAD CITY NC 951 PM EST SAT NOV 11 2006 .SHORT TERM /TONIGHT/...COLD FRONT IS ADVANCING EAST ACROSS THE WESTERN PORTIONS OF THE STATE WITH A BROKEN LINE OF SHOWERS AND A FEW THUNDERSTORMS OUT AHEAD OF IT. WILL SEE AN INCREASE IN PRECIP OVERNIGHT FROM WEST TO EAST AS UPWARD MOTION INCREASES WITH APPROACHING UPPER TROUGH. HAVE ADJUSTED POP GRIDS TO REFLECT CURRENT SAT AND RADAR TRENDS WITH BULK OF PRECIP HOLDING OFF IN WESTERN ZONES UNTIL AFT 06Z AND THEN INCREASING FROM WEST TO EAST TOWARDS DAYBREAK AS FRONT PUSHES ACROSS THE AREA. TEMPS ARE HOLDING IN THE MID 60S INLAND TO UPPER 60S FAR EAST AND OUTER BANKS WITH SOUTHERLY FLOW AHEAD OF FRONT. OVERNIGHT LOWS APPEAR ON TRACK WITH TEMPS DROPPING INTO THE UPPER 50S AND LOWER 60S WITH RAIN DEVELOPING. && .AVIATION...VFR CONDITIONS PREVAIL AT THIS TIME AND SHOULD CONTINUE FOR A FEW MORE HOURS AS PCPN ASCD WITH APPROACHING COLD FRONT IS STILL WELL TO THE WEST. OBSERVATIONS AHEAD OF THE FRONT INDICATE CIGS IN THE 4K TO 5K FT RANGE WITH MINIMAL VSBY REDUCTION WHILE BEHIND THE FRONT CIGS DROP TO AROUND 1500 FT WITH MVFR VSBYS IN RAIN. COULD BE A BRIEF PERIOD OF LOWER CIGS/VSBYS IN CONVECTION LATE TONIGHT BUT OVERALL FEEL CONVECTION WILL BE VERY SHORT LIVED AND CONCENTRATED NEAR THE FRONT AND SCATTERED AT BEST. LOW LVL CLOUDS BEHIND THE FRONT LIKELY TO HANG ON SUNDAY WITH MVFR CIGS THROUGH MUCH OF THE DAY. && .MARINE...WINDS NEAR DIAMOND BUOY INCREASING A BIT FASTER THAN OTHER LOCATIONS LIKELY DUE TO ENHANCED MIXING ON THE WESTERN EDGE OF THE GULF STREAM WHERE SSTS ARE APPROACHING 80 DEGREES. SEAS HAVE RISEN TO 7 FT AT DIAMOND AS WELL...WELL ABOVE THE NEAR SHORE BUOYS THAT ARE REPORTING MAINLY 2 TO 3 FT. SOME CONVECTION IS PRESENT ALONG THE WESTERN EDGE OF THE GULF STREAM AND THE HIER SEAS AT DIAMOND MAY BE IN RESPONSE TO THIS AS WELL. OVERALL THINK GFS IS STILL DOING A SLIGHTLY BETTER JOB WITH WINDS. RUC DOES NOT APPEAR TO INCREASE WINDS ENOUGH THROUGH THE NIGHT. IT IS CLOSER TO THE NAM BUT WITH LESSER SPEEDS. SIG PRESSURE RISES BEHIND THE FRONT SHOULD INDUCE STRONGER WINDS AS PRES GRADIENT BEGINS TO TIGHTEN LATE TONIGHT. HAVE MADE ONLY MINOR ADJUSTMENTS TO WINDS AND GALES OVER CENTRAL WATERS STILL LOOKS GOOD. WILL BUMP UP SEAS CENTRAL WATERS MORE IN LINE WITH DIAMOND OBSERVATIONS THIS EVENING. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY FROM 1 AM SUNDAY TO 3 AM EST MONDAY FOR AMZ135-150-158. SMALL CRAFT ADVISORY FROM 1 AM TO 1 PM EST SUNDAY FOR AMZ130. GALE WARNING FROM 1 AM TO 1 PM EST SUNDAY FOR AMZ152-154-156. && $$ SHORT TERM...WINGENROTH AVIATION...FAUCETTE MARINE...FAUCETTE nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 947 PM EST SAT NOV 11 2006 .SYNOPSIS... THE COLD FRONT HAD COME EAST OFF THE MOUNTAINS AND THROUGH THE PIEDMONT TRIAD AREA AS OF 915 PM. THE MID AND UPPER LEVEL TROUGH (AIDED BY 130 METER 12 HOUR HEIGHT FALLS AT H5 OVER NASHVILLE TN) WAS BEGINNING TO APPROACH THE APPALACHIANS FROM THE TN VALLEY... AND WAS BEGINNING TO TAKE ON A NEGATIVE TILT. SHOWERS AND ISOLATED THUNDERSTORMS ARE EXPECTED TO INCREASE IN COVERAGE AND INTENSITY IN THE NEXT FEW HOURS FROM GSP TO CLT... THEN OVERSPREAD MUCH OF CENTRAL NC OVERNIGHT. POP WILL BE NEAR 100 AND QPF BETWEEN 0.25 TO 0.50 EXPECTED WITH LOCAL 1 INCH AMOUNTS POSSIBLE OVER THE PIEDMONT. && .SHORT TERM /REST OF TONIGHT/... THE LINE OF CONVECTION ASSOCIATED WITH THE COLD FRONT HAS BEEN DIMINISHING IN INTENSITY OVER OUR WESTERN PIEDMONT IN THE PAST HOUR. THE CG LIGHTNING STRIKES HAD GREATLY DECREASED FROM THE LATE AFTERNOON AND EARLY EVENING OVER NW NC... MAINLY DUE TO THE LOSS OF THE REMAINING MINIMAL INSTABILITY. HOWEVER... THE GUST FRONT HAS BEEN FORMIDABLE AS IT ROLLED THROUGH THE TRIAD REGION WITH GUSTS TO 36 MPH REPORTED AT WINSTON- SALEM (827 PM)... AND 31 MPH AT GREENSBORO (905 PM). THIS COLD FRONT IS EXPECTED TO CONTINUE MOVING EAST THROUGH THE PIEDMONT THROUGH 06Z/12 AND THEN SLOW DOWN AS A SURFACE WAVE IS EXPECTED TO DEVELOP ON THE FRONT IN THE VICINITY OF SOP TO RDU BETWEEN 06Z-09Z. 02Z/12 NOVEMBER UPPER AIR DATA INDICATED THE STRONGEST UPPER DIVERGENCE AND MID LEVEL ASCENT WAS LOCATED ON THE NOSE OF A 100 KNOT 300 MB JET... OVER UPSTATE SC EXTENDING INTO THE SW PIEDMONT OF NC NEAR CLT. IR SATELLITE IMAGERY INDICATED COOLING CLOUD TOPS OVER THIS SAME REGION AND RADAR INDICATED AN INCREASE IN ACTIVITY APPROACHING THE SW PIEDMONT OF NC. AS THE MID AND UPPER LOW CONTINUES TO BECOME NEGATIVELY TILTED AND CLOSES OFF AS IT COMES EAST OVER NC TONIGHT... CONDITIONS WILL BE FAVORABLE FOR STRONG MID LEVEL ASCENT TO CONTINUE TO OVERSPREAD CENTRAL NC. IT IS STILL TOO EARLY TO TELL WHICH MODEL SOLUTION REGARDING THE EXACT TRACK THE CUT OFF LOW WILL TAKE LATER TONIGHT AND SUNDAY... BUT THE LATEST RUC AND NEW 00Z/12 NAM SUPPORT THE EARLIER THINKING OF A TRACK THAT WOULD BE ACROSS NC. WITH THE ABOVE IN MIND... THIS UPDATE WILL RAISE THE POP TO 100 ACROSS CENTRAL NC FOR THE OVERNIGHT PERIOD. SHOWERS WILL BECOME WIDESPREAD WITH ISOLATED THUNDERSTORMS THROUGHOUT CENTRAL NC. THE 00Z NAM SUPPORTS THE CURRENT TRENDS... AND IF THE TRACK AND INTENSITY OF THE MID-UPPER LEVEL SYSTEM PROVES CORRECT LATER TONIGHT AND SUNDAY... THERE WILL HAVE TO BE ADJUSTMENTS MADE LATER FOR ADDITIONAL RAIN AND CHILLY TEMPS SUNDAY. NO ADDITIONAL CHANGES AT THIS TIME. && .PREV DISCUSSION... (ISSUED 557 PM EST SAT NOV 11 2006) SYNOPSIS... AT 545 PM... THE COLD FRONT HAD ADVANCED TO THE BLUE RIDGE HAVING PASSED JEFFERSON AND BOONE IN ASHE AND WATAUGA COUNTIES... AND WILL BE MOVING OFF THE BLUE RIDGE AND INTO THE WESTERN PIEDMONT IN THE NEXT FEW HOURS. A SOLID LINE OF SHOWERS AND SCATTERED THUNDERSTORMS HAD DEVELOPED ALONG THE FRONT THROUGHOUT WESTERN NC... WITH ADDITIONAL DEVELOPMENT NEAR GSP SC.. MOVING NE. SHORT TERM /REST OF TONIGHT/... WILL UPDATE THE FORECAST NOW BASED ON CURRENT SATELLITE AND RADAR TRENDS. THE FRONT WILL BE MOVING INTO THE PIEDMONT TRIAD REGION BY MID EVENING (EARLIER THAN PREVIOUS THINKING... ACCOMPANIED BY A LINE OF SHOWERS AND THUNDERSTORMS). WILL RAISE EVENING POP OVER THE WESTERN PIEDMONT TO 100 PERCENT. WILL ADD SCATTERED THUNDERSTORMS. WILL ALSO INDICATE A STRONG WIND SHIFT TO THE NW-N BEHIND THE FRONT WITH GUSTS TO 20-25 MPH. LATER UPDATES WILL BE LIKELY FOR THE EASTERN PIEDMONT AS THE CURRENT WATER VAPOR LOOP INDICATES THE MID AND UPPER LOW APPROACHING THE TN VALLEY IS GOING TO BECOME NEGATIVELY TILTED IN THE NEXT FEW HOURS... AND CLOSE OFF OVERNIGHT IN WESTERN NC. POP WILL HAVE TO BE RAISED TO NEAR 100 EARLIER THAN ANTICIPATED. QPF WILL HAVE TO BE MONITORED CLOSELY AND WILL STRONGLY BE TIED TO EXACTLY WHERE THE CUT OFF FORMS. A DEEPER AND MORE SOUTHERN CUT OFF WILL BRING MUCH HIGHER QPF OVERNIGHT INTO SUNDAY. UPDATE OUT SHORTLY. PREV DISCUSSION... (ISSUED 321 PM EST SAT NOV 11 2006) SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/... MODELS QUICKLY DIVERGE WITH THEIR FORECAST FOR TONIGHT AND INTO SUNDAY WITH ONE SET OF MODELS (INCLUDING THE NAM) DROPING THE 500 MILLIBAR LOW NEAR THE SOUTH CAROLINA BORDER WHILE THE GFS AND OTHERS MOVE THE LOW ALONG THE VIRGINIA BORDER. I CAN FIND NO MAJOR CLUES TO THE CORRECT SOLUTION AND AM RELATIVELY SATISFIED TO GO WITH A COMPROMISE. AS THE UPPER LEVEL LOW IS FORECAST TO DEEPEN AS IT DROPS SOUTH... THE CURRENT THIN LINE OF SHOWERS SHOULD BLOSSOM OVER NORTH CAROLINA INTO A LARGER BLOB TOWARD MIDNIGHT. RAINS SHOULD BEGIN TO EXIT THE WEST AFTER SUNRISE AND LEAVE THE NORTHEAST PARTS IN THE AFTERNOON. IT IS CERTAINLY OPEN TO DEBATE THAT SOME RAINS MAY STILL BE OVER THE ROANOKE RIVER AFTER DARK... BUT WILL LEAVE SUNDAY NIGHT DRY AT THIS TIME. STORM TOTAL PRECIPITATION IN EXCESS OF ONE INCH TOWARD VIRGINIA...TAPERING OFF TO THE SOUTHEAST. CHANCES FOR THUNDER LOOK BEST IN THE WEST AND EARLY IN THE EVENT...BUT LEADING COLD ADVECTION AT THE SURFACE MAY KNOCK THE LEGS OFF OF ANY THUNDER THREAT BEFORE IT BEGINS. LOW LEVEL THICKNESS FALLS FROM THIS EVENING TO SUNRISE SUNDAY ARE FORECAST TO BE ON THE ORDER OF 60 METERS. NO HOPE OF CORRECTLY NAILING DOWN TIMING AND INTENSITY. DID RISK INCREASING THE TEMPERATURE GRADIENT WEST TO EAST ACROSS THE AREA TO TEN DEGREES AND GRADIENT COULD BE A BIT STRONGER. FOUR TO SEVEN DEGREE DIURNAL RISE TO SUNDAY HIGH TEMPERATURES COULD BE TOO HIGH...ESPECIALLY NORTH. LONG TERM /WEDNESDAY THROUGH SATURDAY/... DID NOT SPEND A LOT OF TIME HERE WITH PROBLEMS IN THE SHORT TERM FORECAST. ANOTHER LOW PRESSURE SYSTEM MAY BRING RAINS AS EARLY AS WEDNESDAY AFTERNOON...WITH WEDNESDAY NIGHT PERHAPS THE BETTER BET AT THIS TIME. TEMPERATURES WEDNESDAY AFTERNOON AND THURSDAY MORNING WILL BE ABOVE NORMAL...OTHERWISE NOT STRAYING TOO FAR FROM CLIMATOLOGY. AVIATION... WARM SOUTHERLY FLOW WILL CONTINUE OVER THE AREA THROUGH THE AFTERNOON...WITH SOUTH TO SOUTHWEST WINDS AT 10 TO 15 MPH. MAINLY HIGH LEVEL CLOUDS WILL OVERSPREAD THE AREA IN ADVANCE OF A COLD FRONT. THE FRONT WILL APPROACH THE WESTERN PORTION OF THE REGION THIS EVENING AND TRACK EAST TONIGHT. BROKEN CLOUDS AROUND 10 THOUSAND FEET WILL DEVELOP AFTER 22Z. CONDITIONS WILL LOWER TO MVFR IN RAIN AND FOG AFTER MIDNIGHT IN THE WEST... AND SPREAD EAST AFTER 09Z. MOISTURE WRAPPING AROUND THE ASSOCIATED LOW PRESSURE SYSTEM WHICH WILL BE LOCATED OVER THE SOUTHERN VIRGINIA COAST AFTER 12Z WILL DELAY IMPROVING CONDITIONS UNTIL AFTER 13Z IN THE WEST... 15Z IN THE EAST... AND THE EARLY AFTERNOON IN THE NORTHEAST. WINDS WILL SHIFT TO THE WEST AT 10 TO 20 MPH AFTER 09Z ...AND TO THE NORTHWEST BETWEEN 13Z AND 15Z FOLLOWING THE FRONTAL PASSAGE. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS... SHORT TERM...BADGETT/MLM/STRICKLER nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TULSA OK 845 PM CST SAT NOV 11 2006 .UPDATE... THE LATEST RUC ANALYSIS PLACES THE CENTER OF SURFACE HIGH PRESSURE NEAR THE NW CORNER OF ARKANSAS AND NE CORNER OF OKLAHOMA AT THIS HOUR. CONSEQUENTLY... TEMPERATURES IN THAT PORTION OF THE FORECAST AREA HAVE FALLEN RAPIDLY TO NEAR FORECAST MINIMUMS. SEVERAL OTHER SITES FURTHER WEST ACROSS NORTHERN OKLAHOMA HAVE ALSO DROPPED A LITTLE MORE THAN EXPECTED. COPIOUS HIGH CLOUDS TO OUR NORTH AND WEST SHOULD HAVE TROUBLE MAKING IT INTO THE REGION WITH THE BUILDING UPPER RIDGE. HAVE THEREFORE LOWERED OVERNIGHT MINIMUMS SEVERAL DEGREES ACROSS BASICALLY OUR NORTHERN TIER OF COUNTIES. HAVE ADJUSTED HOURLY GRIDS FOR TEMP AND RH AND SENT ALL UPDATED PRODUCTS. && .PREV DISCUSSION... (ISSUED 240 PM CST SAT NOV 11 2006) DISCUSSION... A COLD NIGHT IN STORE TONIGHT WITH SURFACE HIGH PRESSURE PROVIDING CLEAR SKIES AND LIGHT WINDS. TEMPS TONIGHT EXPECTED TO BE WELL DOWN INTO THE 30S...WITH NORMALLY COOLER SPOTS FALLING BELOW FREEZING. SOUTHERLY WINDS RETURNING IN WESTERN AREAS BY MORNING...AS THE SURFACE HIGH SLIDES OFF TO THE EAST...SHOULD KEEP TEMPS IN WESTERN ZONES FROM REALLY BOTTOMING OUT. LOOKS LIKE A FEW UNEVENTFUL DAYS FOR SUNDAY AND MONDAY AS ANOTHER WAVE BYPASSES THE AREA TO THE NORTH. A WEAK BOUNDARY SHOULD MAKE ITS WAY INTO THE AREA LATE SUNDAY NIGHT...BUT NOT ENOUGH MOISTURE TO WARRANT ANY POPS OVER THE AREA AND NO DRAMATIC TEMPS CHANGES EXPECTED. TEMPS SUNDAY AND MONDAY SHOULD BE GENERALLY NEAR SEASONAL NORMS...THEN SLIGHTLY WARMER ON TUESDAY AHEAD OF NEXT DEVELOPING SYSTEM. HAVE ALSO ADDED SOME LOW POPS ON TUESDAY AS MODELS BEGIN TO ORGANIZE A TROUGH THAT WILL DEEPEN OVER THE PLAINS OR JUST TO THE EAST TUESDAY INTO WEDNESDAY. SOMEWHAT HIGHER POPS TUESDAY NIGHT...THEN LINGERING LOW POPS IN THE EAST WEDNESDAY BEFORE SYSTEM MOVES OFF TO THE EAST. USUAL TIMING/STRENGTH ISSUES...SO HAVE NOT GOTTEN TO CARRIED AWAY WITH POPS JUST YET. MODELS DO APPEAR TO BE TRENDING TOWARD A WETTER SOLUTION THROUGH...ESPECIALLY TO THE EAST OR NORTHEAST. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...NONE. AR...NONE. && $$ SHORT TERM FORECASTER ID= 15 LONG TERM FORECASTER ID= 6 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 852 PM EST SAT NOV 11 2006 .SHORT TERM /REST OF TONIGHT/... FRONT CONTINUES TO PUSH EASTWARD TOWARDS OUR AREA...JUST NOW MVG INTO THE WESTERN PORTIONS OF VA. UPR TROUGH HAS PASSED THROUGH W INDIANA...WITH MODELS CONTINUING TO SHOW AN UPR LOW BECOMING CUT-OFF NEAR OH/E KY/WV REGION OVER THE NEXT 6 HRS. DECENT AREA OF RAIN BEHIND THE FRONT THIS EVNG SHOULD INTENSIFY OVER OUR AREA AS THIS UPR LOW DVLPS. ALL IN ALL...TS POTENTIAL IS RATHER LOW DUE TO ONLY WEAK INSTABILITY. MID LVL LAPSE RATES NOT ALL THAT IMPRESSIVE...ONLY ABOUT 6 DEGREES C. LI'S ARE NEAR ZERO TO SLIGHTLY POSITIVE. 0-6KM SHEAR HOWEVER IS SUFFICIENT TO SUPPORT UPDRAFTS THAT COULD PRODUCE HAIL (ABOUT 50KTS ACCORDING TO RUC ANALYSIS) AND IN FACT HAIL WAS REPORTED IN WATAUGA COUNTY IN NC...RIGHT ALONG THE NC/W VA BORDER. THEREFORE...ANY ISOLD TS THAT WE DO SEE MAY PRODUCE SOME HAIL PROBABLY AROUND A QUARTER TO HALF INCH. BY FAR...THE BIGGER THREAT WITH THIS SYSTEM WILL BE HEAVY RAIN...AND HOW LONG THE RAIN HANGS AROUND WILL DETERMINE ANY TYPE OF FLOODING POTENTIAL. MODEL DIFFERENCES...THE GFS TAKES THE UPR LOW TO THE EASTERN BORDER OF VA/NC BY MIDDAY SUNDAY (18Z) WHILE THE NAM TAKES THE LOW INTO E-CNTRL NC BY MIDDAY. ALTHOUGH WE'RE ONLY TALKING ABOUT A 100 MILE DIFFERENCE...THIS SIGNIFICANTLY IMPACTS WHERE THE HEAVIEST RAINFALL WOULD BE OVERNIGHT AND INTO TOMORROW. GOING WITH A BLEND OF THE TWO MODELS AS WELL AS LOOKING AT HPC'S PRECIP GRAPHICS...IT APPEARS THAT THE HEAVIEST RAIN WILL FALL OVER THE VA PIEDMONT AND CNTRL VA. AMOUNTS COULD BE UP TO THREE INCHES IN SOME LOCATIONS...WITH AN AVERAGE OF 1-2 INCHES ACROSS THE AREA. WHILE THIS WOULDN'T PROMPT A FLOOD WATCH AT THIS TIME...WILL ISSUE AN SPS SHORTLY TO OUTLINE THIS THREAT AND CONTINUE TO MONITOR UPSTREAM TRENDS OVER THE NEXT FEW HRS. WILL UPDATE ZONES SHORTLY TO INCREASE POPS SLIGHTLY LATE THIS EVNG...AND ALSO TO INCLUDE HEAVY RAIN WORDING OVERNIGHT AND EARLY TOMORROW. REST OF THE FCST LOOKS GOOD. && .PREV DISCUSSION... (ISSUED 256 PM EST SAT NOV 11 2006) SHORT TERM /TONIGHT THROUGH MONDAY/... SPLENDID WX FOR TDA...INCLDG RCRD-BRKG TEMPS (AT LEAST AT SBY SO FAR)...WRM/SSWLY FLO PREVAILS AS SFC HI PRES OFFSHR WKNS. MNWHL...STRNG CDFNT ENTERING THE MTNS ERY THIS AFTN. WHL TEMPS ARE IN THE 70S IN MANY SPOTS E OF THE MTNS (IN VA/NC)...W OF MTNS (OH/KY/TN)...RDGS ONLY IN THE LWR/MID 40S. PCPN IS CURRENTLY ALG/RIGHT BEHIND THE FNT...W/ NOTHING SO FAR E OF IT IN WRMSCTR. XPCTG THAT TO LRGLY CONT THROUGH THIS EVE AS FNT MVS ONTO THE HIGHLANDS IN WRN VA/NC. JUST AS NICE/WRM AS TDA HAS BEEN...SUN WL BE QUITE THE OPPOSITE. MDLS CONTG TO DEPICT VIGOROUS UPR LVL LO PRES DVLPMNT LT TNGT/ERY SUN ACRS SW VA/NW NC AS THE STRNG SFC CDFNT PUSHES TO THE CSTL PLN (LT TNGT) AND OFFSHR (SUN MORNING). XPCTG WDSPRD AREA OF RA TO DVLP (ACRS WRN/CNTRL VA) AS UPR LVL SYS BCMS CLSD OFF. IMPRESSIVE/DP LYR UVM AND MSTR SUGG PTNTL FOR HVY RA ACRS MUCH OF FA LT TNGT THROUGH SUN MORNING AS CONVEYOR BELT INTENSIFIES W/ THE UPR LVL DVLPG JUST WSW OF FA. AS UPR LVL LO PRES TRACKS ACRS SRN VA SUN AFTN...MOD SFC LO PRES FORMS INVOF VA CAPES...LIKELY KPG RA ACRS MUCH OF THE FA THRUT THE DAY SUN. AS W/ SYS ERYR THIS WK (THAT PASSED NRLY OVRHD ACRS FA)...CANNOT RULE OUT PSBL T FM LT TNGT THRU SUN. AVG QPF ONCE AGN LOOKS TO BE 1 TO 1.5 IN (HV HAD QUITE A FEW OF THESE TYPES OF SYSTEMS IN PAST CPL MONTHS - WL THAT CONT INTO THE UPCOMING WINTER SEASON?). TEMPS RMNG MILD TNGT (LOWS IN LWR/MID 50S)...THEN NOTICEABLY/SHARPLY COOLER FOR SUN (AND RDGS WL LIKELY BE AT HIEST LVLS ERY IN THE DAY...B4 HOLDING STDY OR EVEN FALLING DURG MIDDAY/AFTN HRS IN MANY SPOTS. BY THE END OF THE DAY...MANY LCTNS AWAY FM THE CST WL PRBLY HV TEMPS IN THE 40S. STM SYS SLO TO PULL AWAY FM THE RGN SUN NGT THROUGH MON...KPG PLNTY OF CLDS AND CHC POPS SUN NGT ALL AREAS...THEN LMTD TO THE ERN SHR BY MIDDAY/AFTN MON. XPCTG SLO DRYING/CLRG ACRS THE FA BY MON AFTN. LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... WK RIDGING MVS ACRS RGN MON NGT THROUGH ERY WED...B4 NEXT VIGOROUS TROUGH ALOFT AMPLIFIES W OF THE MTNS (WED AFTN) AND PROGRESSES EWD TO THE E CST (THU). HOLDING OFF ON NEXT CHC OF PCPN UNTIL LT WED NGT AND THU W/ MOD CDFNTL PASSAGE. STILL LOOKS TO DRY OUT FRI INTO NEXT WKND. AVIATION... VFR THRU THE EVENG...WITH DETERIORATING CONDS WELL AFTER MIDNGT. BRING PRECIP INTO TAF SITES 09/11Z FROM W TO E. UPR LOW WILL BRING TEMPO MVFR/IFR IN SHWRS/LOW CLDS ON SUNDAY...MAY EVEN ALLOW FOR SOME THUNDER...BUT NOT IN TAFS AT THIS PT. MARINE... APPROACH OF SLOW MVG UPPER LOW TONIGHT MAKES FOR AN INTERESTING MARINE FCST...ALONG WITH LARGE DIFFS BETWN GFS AND NAM/WRF. WINDS HAVE STRUGGLED TO MIX DOWN TODAY OVER THE COOL WATERS...GNRLY JUST 10-15 KTS THIS AFTN...EXPECT TO COME UP A BIT MORE THIS EVENG BUT WILL KEEP JUST BELOW SMALL CRAFT FOR NOW. BY ERLY SUN MRNG WINDS LIGHTEN UP AS SFC LOW BECOMES CNTRD OVERHD...ALTHOUGH ENOUGH OF A S TO SSE SURGE ALONG THE COAST FOR SEAS INCREASING TO 4-5 FT. BY MID TO LATE DAY SUNDAY BAY LOOKS TO SEE A NLY SURGE OF SMALL CRAFT WHILE CSTL WTRS THIS SURGE HOLDS OFF UNTIL LATER SUN NGT/ERLY MON. TAKING A GFS/NAM/WRF CONSENSUS LEADS TO ALL ZONES INTO SMALL CRAFT FROM MIDDAY SUNDAY THRU MIDDAY MONDAY. QUIETER CONDS MON NGT/TUE/TUE NGT. NXT SYSTM MAKING THU OUT TO BE ANOTHER SMALL CRAFT EVENT. CLIMATE... SBY SET A RCRD HI TEMP AT 75 DEGS F ARND 1241 PM THIS AFTN (PREV RCRD WAS 74/2002)...WATCHING OTR SPOTS...ESP RIC FOR THE REST OF THE LT AFTN. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FOR ANZ650-652 UNTIL 6 PM MONDAY. ...SMALL CRAFT ADVISORY FOR ANZ654-656-658 FROM 6 AM SUNDAY TO 1 PM MONDAY. ...SMALL CRAFT ADVISORY FOR ANZ630>633 FROM NOON SUNDAY TO 1 PM MONDAY. && $$ SHORT TERM...MCNATT va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 358 AM EST SUN NOV 12 2006 .SHORT TERM...TODAY AND TONIGHT MODELS IN PRETTY GOOD AGREEMENT AS FOR THE SYNOPTIC PICTURE. SURFACE RIDGE TO PASS SLOWLY EAST ACROSS SOUTHEAST MI TODAY INTO TONIGHT. AT 500 MB...MEANWHILE...SHORTWAVE RIDGE OVERHEAD TODAY TO RETREAT EAST TONIGHT. EXCEPT AS NOTED BELOW...OVERALL DESCENT SEEN IN OMEGA FIELDS TODAY INTO TONIGHT...WITH QVECTOR CONVERGENCE ALSO INDICATING MOSTLY DIVERGENCE/SUBSIDENCE. 850 TO 500 MB MOISTURE RATHER MEAGER THROUGH TONIGHT. INCREASING CIRRUS...THOUGH...LIKELY TO BE SEEN MAINLY LATE TONIGHT BEHIND RIDGE ALOFT. LOW LEVEL MOISTURE...AS AT 925 MB...EXPECTED TO DIMINISH TODAY. THE EXCEPTION TO NO WEATHER IS THE OVERNIGHT SPRINKLES AND FLURRIES SEEN OVER MUCH OF THE FORECAST AREA...LARGELY RELATED TO LAKE EFFECT FROM NORTH TO NORTHEAST FLOW OFF OF LAKE HURON. DELTA TS INTO THE LOWER TEENS EARLIER IN THE NIGHT SHOULD LESSEN STEADILY THIS MORNING AS 850 MB TEMPERATURES WARM BEHIND THE BRIEF THERMAL TROUGH. NAM/RUC AND GFS SHOW GOOD LOW LEVEL CONVERGENCE...TENDING TO MAXIMIZE AROUND 06Z...ALSO ON THE WANE THIS MORNING. NAM ALSO SHOWS MODEST 950 MB OMEGA LIFT...MAINLY IN THE THUMB...WANING THIS MORNING. WILL CARRY MENTION OF SPRINKLES OR FLURRIES INTO THE MORNING FOR MOST OF THE AREA...THEN RIDGE OVERHEAD THIS AFTERNOON SHOULD KILL OFF ANY MORE POSSIBILITY OF THIS TRACE PRECIPITATION. PERSISTENCE OF SPRINKLES...AS OPPOSED TO FLURRIES...SEEMS RELATED TO SHALLOW DEPTH OF MOISTURE AND THUS VERY POOR ICE NUCLEATION POTENTIAL...AS PER MODEL SOUNDINGS. AS FOR CLOUD COVER TODAY...MOST MODELS INDICATE LESSENING BY AFTERNOON...AND WILL SO INDICATE. SATELLITE IMAGERY ALREADY SHOWING SOME THIN SPOTS/HOLES IN THE CLOUD COVER. DAYTIME MIXING SHOULD AID IN CLOUD COVER DECREASE. && .LONG TERM...MONDAY THROUGH SUNDAY CONFIDENCE IS INCREASING FOR A POTENT STORM TO IMPACT THE REGION FOR MID WEEK...HOWEVER...PREDICTABILITY OF THE EVENTUAL UPPER FLOW REGIME ACROSS THE CONUS REMAINS BELOW AVERAGE. SATELLITE DERIVED WINDS IN THE EASTERN PACIFIC AS OF 03Z WERE AVERAGING AROUND 120KTS WITH A DEVELOPING JET STREAK APPROACHING 150KTS EAST OF 150W INBETWEEN 40-50N. GLOBAL MODELS SEEM TO HAVE INITIALIZED THE PACIFIC JET ORIENTATION AND GENERAL STRENGTH AS THE ECMWF APPEARS TO HAVE PICKED UP THE JET STREAK EARLIER THAN THE OTHER OPERATIONAL GLOBAL MODELS. THIS FEATURE(S) WILL BE OUR FORECAST CHALLENGE FOR THIS UPCOMING WEEK. BEGINNING WITH MONDAY...LONG WAVE TROUGH CURRENTLY PROGRESSING THROUGH THE INTERMOUNTAIN WEST AND EMBEDDED SHORT WAVE ACROSS THE FOUR CORNERS WILL LIFT NORTHEAST THROUGH THE DAY AS SHORT WAVE RIDGE AND SURFACE HIGH PRECEDING IT SLIDES FURTHER EAST. WHILE A GOOD AERIAL COVERAGE OF PRECIP IS EXPECTED TO ACCOMPANY THIS FEATURE INITIALLY...DECREASING THERMAL GRADIENT IN THE LOW-MID LEVELS ACROSS THE MID-UPPER MISSISSIPPI RIVER VALLEY AND BEST UPPER SUPPORT WILL LIFT INTO CANADA AND REDUCE THE CHANCES OF PRECIP FOR THE CWA. IN FACT...HARD TO FIND A MODEL THAT PRINTS ANY QPF ACROSS THE CWA. DO NOT FEEL COMPELLED TO REMOVE POPS COMPLETELY AND WILL RETAIN THE CURRENT FORECAST WITH 20% POPS ALONG AND NORTH OF 8-MILE WITH 30% POPS AROUND THE TRI CITIES. THEN A BRIEF RESPITE MONDAY NIGHT INTO TUESDAY AS WEAK SURFACE HIGH AND SHORT WAVE RIDGE AXIS MOVES ACROSS THE GREAT LAKES. HOWEVER... LOW LEVEL MOISTURE REMAINS RATHER HIGH AS OBSERVED IN THE GFS/NAM/WRF-HEMI SOUNDINGS HENCE THE PERCENT CLOUD COVER WILL REMAIN RATHER HIGH THROUGH EARLY TUESDAY MORNING. POTENT PACIFIC JET COMES ASHORE AND DIVES SOUTHEAST INTO THE THE FOUR CORNERS REGION TUESDAY NIGHT WITH SURFACE LOW DEVELOPING IN THE VICINITY OF THE PANHANDLE OF TEXAS. DEPENDING ON HOW THIS PATTERN UNFOLDS ACROSS THE CONUS...TRENDS IN THE GLOBAL MODELS SUGGEST UPPER PATTERN QUICKLY BECOMES NEGATIVELY TILTED AS GULF OF MEXICO MOISTURE ADVANCES NORTHWARD WEDNESDAY-WEDNESDAY NIGHT. CROSS SECTIONS FROM THE GFS SHOW A RATHER POTENT PETTERSSEN 2-D FGEN LAYER BETWEEN 850-700MB WITH AN INCREASED SLANTWISE INSTABILITY (INCLUDING DEPTH) JUST ABOVE THIS LAYER AS SUGGESTED IN THE LOWERING EPV/S ACROSS THE CWA. COULD SEE A BAND(S) OF HEAVY RAIN AND THUNDER WEDNESDAY AFTERNOON INTO THURSDAY MORNING...THIS WILL NEED TO MONITORED CLOSELY AS PWATS ARE EXPECTED TO CLIMB IN EXCESS OF 1 INCH. LOW BECOMES VERTICALLY STACKED ACROSS THE STATE THROUGH THURSDAY WITH A SLOW RETREAT NORTHWARD THROUGH THE END OF THIS WEEK. 850MB TEMPS DROP BACK TOWARD THE NEGATIVE TERRITORY AND PERHAPS EVEN LOWER INTO THE WEEKEND AS UPPER FLOW AMPLIFIES TOWARD A RIDGE ACROSS THE ROCKIES AND A TROUGH ACROSS THE GREAT LAKES/MIDDLE ATLANTIC COAST. THIS SETS THE STAGE FOR THE CHANCE OF SNOW SHOWERS FROM THE COLD/MOIST CYCLONIC FLOW AND CONTRIBUTIONS FROM LAKE MICHIGAN. WILL GO LOWER THAN MEX NUMBERS AND ADD POPS FOR SNOW THROUGH AT LEAST NEXT SATURDAY. && .PREV DISCUSSION... AVIATION... SURFACE HIGH PRESSURE WILL GRADUALLY BUILD INTO LOWER MICHIGAN TONIGHT. DESPITE THIS HIGH...LOW LEVEL MOISTURE FLUX OVER LAKE HURON WITH NORTH-NORTHEASTERLY FLOW HAS ALLOWED PLENTY OF MOISTURE TO BECOME TRAPPED UNDERNEATH A STRONG LOW LEVEL INVERSION. ALTHOUGH THERE HAVE BEEN A FEW BREAKS IN THE CLOUDS...PREDOMINATE MVFR CEILINGS ARE WIDESPREAD ACROSS THE AREA. CLOUDS WILL PERSIST THROUGH 12Z...THEN THERE WILL BE A GRADUAL IMPROVEMENT DURING THE REST OF THE MORNING AS THE SURFACE RIDGE MOVES OVERHEAD AND LOW LEVEL DRY AIR ADVECTION PERSISTS. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421... NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON UNTIL 5 PM SUNDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ SHORT TERM...DWD LONG TERM....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 UPTON NY 429 AM EST SUN NOV 12 2006 .NEAR TERM (TODAY)... AT 8Z WATER VAPOR AND 500MB RUC ANALYSIS SHOWED 500MB LOW HAD FINALLY CUTOFF OVER SOUTHERN WEST VIRGINIA...WITH AN INTENSE VORTICITY MAXIMA OVER WESTERN SOUTH CAROLINA (40 VORTICITY UNITS ACCORDING TO THE RUC...IMPRESSIVE)...AND AT THE SURFACE A BROAD AREA OF LOW PRESSURE CENTERED OVER SOUTH CENTRAL VIRGINIA...WITH 2.4 MB PRESSURE FALLS OVER THE PAST 3 HOURS OVER EAST CENTRAL NORTH CAROLINA. CONVECTION DEVELOPING OFF THE NORTH CAROLINA COAST AND POSITIVE VORTICITY ADVECTION FROM THE 500 MB LOW/VORTICITY MAXIMUM WILL CONTINUE TO SUPPORT PRESSURE FALLS NEAR THE EAST CENTRAL NORTH CAROLINA COAST...AND SHOULD LEAD TO COASTAL LOW FORMATION BETWEEN CAPE HATTERAS AND CAPE LOOKOUT NC THIS MORNING. THIS DATA BASED FORECAST IS IN STRONG AGREEMENT WITH THE 0Z/6Z NAM/0Z NGM AND TO A LESSER EXTENT THE 0Z ECMWF AND 3Z SREF ENSEMBLE MEAN (BOTH ARE A LITTLE NORTH OF CAPE HATTERAS WITH THEIR COASTAL LOW AT 12Z THIS MORNING). THE 0Z GFS DEVELOPS THIS LOW NEAR THE SOUTHEAST VIRGINIA COAST THIS MORNING...AS DO THE 0Z UKMET AND CANADIAN (BUT A TAD FURTHER SW). BASED ON THE DATA SUPPORTING THE NAM/NGM AND TO A LARGE DEGREE ECMWF/SREF ENSEMBLE MEAN SOLUTIONS...HAVE USED THE NAM FOR TIMING THE ONSET OF PRECIPITATION (ALSO NOTING THAT IT DID A VERY GOOD JOB CAPTURING THE BATCH OF SHOWERS WITH ISOLATED THUNDERSTORMS THAT MOVED CROSS THE EAST FORK OF LONG ISLAND/FAR SOUTHEAST CT OVERNIGHT). BASED ON THIS...AND THE LATEST RADAR TRENDS SHOWING NO EASTWARD PROGRESS (ACTUALLY SLIGHT WESTWARD DRIFT) TO RAIN SHIELD OVER CENTRAL PA/NY...EXPECT MOST PRECIPITATION TO HOLD OF UNTIL THIS AFTERNOON...SO ONLY HAVE SLIGHT CHANCE POPS TO START THIS MORNING...INCREASING TO CHANCE POPS BY LATE MORNING (HIGHEST WEST)...THEN CATEGORICAL POPS THROUGHOUT THIS AFTERNOON. HAVE SLIGHT CHANCE OF THUNDER IN THIS MORNING OVER EASTERN AREAS...NOTING THAT WE ALREADY HAVE HAD THUNDER OVERNIGHT...AND ALL MODELS SHOW SUB ZERO SHOALWATER INDICES (SUPPORTING ELEVATED CONVECTION)...AND LIFTED INDICES NEAR ZERO THIS MORNING. DEVELOPING SOUTHEAST TO EAST BOUNDARY LAYER FLOW THIS AFTERNOON...WILL BRING IN A SUFFICIENT MARINE LAYER TO PREVENT DEEP CONVECTION (AS SHOWN BY ALL MODELS INCREASING THE SHOALWATER INDEX TO ABOVE 0 AND MOST ABOVE 2 THIS AFTERNOON). AS FAR AS TEMPERATURES GO ALL BUT ORANGE/WESTERN PASSAIC COUNTIES ALREADY HAVE TEMPERATURES AROUND 60...SO USED WARMEST AVAILABLE GUIDANCE FOR HIGHS. EXPECT TEMPERATURES TO GENERALLY RISE 3-5 DEGREES FROM CURRENT LEVELS BEFORE ONSET OF STEADIER PRECIPITATION THIS AFTERNOON...SO IN THE HOURLY TEMPERATURES HAVE TEMPERATURES PEEKING AROUND MIDDAY...THEN STEADY OR SLOWLY FALLING DURING THE AFTERNOON. HAVE QUITE A LARGE NUMBER OF OBSERVATIONS OF VISIBILITIES OF 2 MILES OR LESS...SO HAVE PATCHY FOG IN THE ZONES THIS MORNING. AS SOUTHEAST TO EAST FLOW SETS UP AND STRENGTHENS BY THIS AFTERNOON IN THE BOUNDARY LAYER THE FOG SHOULD MIX OUT...BUT THIS SHOULD PROMOTE PATCHY DRIZZLE IN THE AFTERNOON (ESPECIALLY OVER LONG ISLAND AND COASTAL CT) WHEN IT IS NOT RAINING. && .SHORT TERM (TONIGHT THROUGH WEDNESDAY)... WHILE I INITIALLY PREFER THE NAM WITH STORM TRACK...OVER TIME IT BECOMES THE SLOWEST IN LIFTING THE STORM TO THE NORTH...AND HAS BEEN IN THE PAST FEW RUNS SLIGHTLY ACCELERATING ITS SOLUTION AND SHIFTING IT FURTHER WEST. THIS IS STILL TRUE WITH THE 6Z NAM...WHICH IS FURTHER WEST AND NORTH THAN THE 0Z NAM AT 0Z WEDNESDAY. THE GFS REMAINS THE FASTEST MODEL LIFTING NORTH...AND IS AN OUTLIER IN THIS...SO HAVE DISREGARDED IT. THE 0Z UKMET/ECMWF/3Z SREF ENSEMBLE MEAN ARE A REASONABLE SOLUTION IN TERMS OF SPEED (THOUGH THE ECMWF IS FURTHER EAST THAN THE OTHER 2...ALSO FURTHER EAST THAN THE 6Z NAM)...SO FOLLOWED THE 12Z UKMET/3Z SREF FOR THE LOW TRACK BY TUESDAY MORNING. CURRENTLY EXPECT THE LOW TO BE CENTERED SOUTH OF MONTAUK POINT TUESDAY MORNING...THEN LIFT NORTH ACROSS/JUST TO THE EAST OF FAR EASTERN PORTIONS OF THE CWA TUESDAY MORNING/EARLY TUESDAY AFTERNOON. THIS LOW TRACK MADE NECESSARY CHANGES TO THE CURRENT FORECAST. THE MAIN CHANGE IS THE SHIFT OF THE AXIS OF QPF TO THE EAST. WHILE EXACT DETAILS ARE IN THE HYDROLOGY SECTION...THIS RESULTS IN DROPPING THE FLOOD WATCH. EXPECT PERIODS OF RAIN THIS AFTERNOON AND EVENING WITH PATCHY DRIZZLE AS THE TROUGH ASSOCIATED WITH THE DEVELOPING COASTAL LOW CROSSES THE AREA...THEN EXPECT A LULL FROM LATE TONIGHT INTO MONDAY MORNING AS THE COASTAL LOW CONSOLIDATES AND LIFTS SLOWLY NORTH AND EAST. HAVE LOWERED POPS TO CHANCE DURING THIS TIME...AS IT WILL BE MAINLY PREDOMINATED BY DRIZZLE. INCREASE POPS TO LIKELY MONDAY AFTERNOON AND NIGHT AS COASTAL LOW GETS BETTER ORGANIZED AND DRAWS NEAR. FOCUS LIKELY POPS TUESDAY MORNING (IN COLLABORATION WITH SURROUNDING OFFICES) OVER EASTERN AREAS TUESDAY MORNING AS LOW PASSES WITH CHANCE POPS EAST...THEN CHANCE POPS TUESDAY AFTERNOON (REFLECTING UNCERTAINTY IN TIMING/EXACT TRACK OF LOW)...THEN SLIGHT CHANCE POPS TUESDAY EVENING (EXCEPT LOW CHANCE POPS FAR EAST (CLOSEST TO LOW)...THEN SLIGHT CHANCE POPS AFTER MIDNIGHT TUESDAY NIGHT...ALSO REFLECTING UNCERTAINTY IN APPROACH OF NEXT SYSTEM. AS FAR AS TEMPERATURES TODAY THROUGH TUESDAY NIGHT FOLLOWED A BLEND OF AVAILABLE GUIDANCE. MADE NO CHANGES TO THE FORECAST ON WEDNESDAY...AS SOUTHERLY FLOW SETS UP OVER THE REGION AHEAD OF THE NEXT SYSTEM WHICH SHOULD BE LOCATED OVER THE UPPER OHIO RIVER VALLEY/LOWER GREAT LAKES BY WEDNESDAY EVENING. && .LONG TERM (WEDNESDAY NIGHT THROUGH SATURDAY)... 0Z ECMWF/GFS IN REASONABLE DEGREE OF AGREEMENT OVER MEDIUM RANGE...REFLECTING THE SET UP OF A TROUGH OVER THE EASTERN US BY THE END OF THIS WEEK...THE FORECAST IN GENERAL REFLECTS THIS...SO COUPLED WITH MORE PRESSING SHORT TERM CONCERNS...MADE NO CHANGES TO THE EXTENDED FORECAST. && .AVIATION... GENERALLY IFR CONDITIONS ARE LIKELY THROUGH 06Z MON. SOME SPOTS WILL SEE MVFR OR LIFR/VLIFR AT TIMES...BUT THESE WILL TEND TO BE THE EXCEPTION RATHER THAN THE RULE. SATURATED LOW LEVELS HAS LED TO A GOOD BIT OF FOG EARLY THIS MORNING...LOCALLY DENSE. EXPECT THE FOG TO BECOME LESS PREVALENT LATER THIS MORNING AS NE FLOW KICKS IN...BUT IFR CIGS WILL CONTINUE. RAIN WILL BE DEVELOPING DURING THE DAY AS WELL...LIKELY BECOMING WIDESPREAD IN THE AFTERNOON. THE RAIN COULD BE HEAVY AT TIMES DURING THE AFTERNOON AND EVENING WITH CIGS/VSBYS DROPPING DOWN INTO THE LIFR CATEGORY. STEADY RAIN WILL GIVE WAY TO MORE OF A DRIZZLE SITUATION LATE TONIGHT...BUT THERE IS LITTLE HOPE FOR IMPROVING AVIATION CONDITIONS THROUGH 12Z MON. THE NEXT TAF PACKAGE WILL LIKELY REFLECT IFR OR WORSE CONDITIONS CONTINUING THROUGH THAT TIME. LGT/VRBL WINDS WILL BECOME E THEN NE THIS MORNING. SPEEDS WILL RANGE FROM 6-12 KT. NE FLOW WILL INCREASE A BIT TONIGHT INTO THE 10-15 KT RANGE. && .MARINE... WIND FCST REMAINS DIFFICULT AS 00Z MODELS CONTINUE TO PRESENT A VARIETY OF SOLUTIONS WITH RESPECT TO THE PLACEMENT AND INTENSITY OF LOW PRESSURE ALONG THE MID ATLANTIC COAST DURING THE NEXT 24-48 HOURS. BASICALLY THE GFS IS FASTEST TO MOVE THE SFC LOW NORTHWARD INTO NEW ENGLAND...THEN NAM IS THE SLOWEST AND FURTHEST OFFSHORE...AND THE UKMET AND ECMWF ARE IN BETWEEN. THIS RESULTS IN QUITE A BIT OF SPREAD FOR THE MODEL WIND FCSTS. MOSTLY WENT CLOSE TO THE NAM...BUT ADJUSTED DIRECTIONS/SPEEDS SOMEWHAT TO FIT BETTER WITH THE OTHER MODELS AND SURROUNDING OFFICES. RESULT IS NE FLOW DEVELOPING TODAY... THEN INCREASING TONIGHT AND REMAINING RATHER BRISK ON MON. THE PERSISTENT NE FLOW WILL CAUSE SEAS TO BUILD REACHING 6 TO 9 FT MON AND MON NIGHT. FLOW GRADUALLY BACKS TO NORTH ON TUE AS THE LOW PASSES BY...LIKELY JUST TO THE EAST OF THE LOCAL WATERS. THIS WILL ALLOW SEAS TO SUBSIDE. BASED ON THE ABOVE FCST...NO CHANGES ARE NEEDED TO THE EXISTING SCA FOR THE OCEAN ZONES...WHICH RUNS THROUGH TUE AFTERNOON. LONG PERIOD OF BRISK NE FLOW WILL CAUSE WATER TO PILE UP IN WESTERN LONG ISLAND...AS WELL AS IN NY HARBOR AND THE BACK BAYS OF THE LONG ISLAND SOUTH SHORE. FORTUNATELY ASTRONOMICAL TIDES ARE RELATIVELY LOW FOR THE NEXT COUPLE OF DAYS...AND 2.5 TO 3 FOOT DEPARTURES WILL BE NEEDED TO REACH MINOR COASTAL FLOODING THRESHOLDS. CURRENT GUIDANCE SUGGESTS THAT WE WILL PROBABLY REMAIN BELOW THOSE LEVELS AT MOST LOCATIONS...AND ANY COASTAL FLOODING WOULD BE ISOLATED AND MINOR AT WORST. GREATEST POSSIBILITY FOR ANY FLOODING THAT MIGHT OCCUR WOULD LIKELY BE DURING THE MON AFTERNOON AND LATE MON NIGHT HIGH TIDE CYCLES. WILL NEED TO CONTINUE MONITORING OVER THE NEXT COUPLE OF DAYS. && .HYDROLOGY... EXPECTED STORM TRACK SHIFTS THE AXIS OF HEAVIEST QPF OVER THE NEXT 48 TO 60 HOURS EASTWARD OVER CONNECTICUT AND LONG ISLAND. THIS IS THE AREA OVER WHICH ALL MODELS CURRENTLY AGREE WILL RECEIVE 1 TO 1.5 INCHES OF RAIN. TO THE WEST...MODELS GENERALLY AGREE ON 0.75 TO 1 INCH OF RAIN OVER THE CURRENT FLOOD WATCH AREA. THIS IS MUCH LESS (BY A FACTOR OF 75 TO 100 PERCENT) THAN CURRENT 12-24 HOUR FLASH FLOOD GUIDANCE OVER NORTHEAST NEW JERSEY AND THE LOWER HUDSON VALLEY...SO I HAVE OPTED TO CANCEL THE FLOOD WATCH THERE (IN COLLABORATION WITH MT HOLLY). THE EXPECTED RAINFALL OVER CONNECTICUT AND LONG ISLAND IS ALSO 75 TO 100 PERCENT BELOW FLASH FLOOD GUIDANCE...SO THERE WAS NO NEED (IN COLLABORATION WITH SURROUNDING OFFICES) TO PUT THOSE AREAS IN A WATCH. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NJ...NONE. NY...NONE. MARINE...SMALL CRAFT ADVISORY FOR ANZ350-353-355 UNTIL 5 PM TUESDAY. && $$ PUBLIC/HYDROLOGY...MALOIT AVIATION/MARINE...CNJ ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 230 AM CST SUN NOV 12 2006 LOW POP PCPN CHANCES/PHASE AND TEMPERATURES REMAIN FORECAST CHALLENGES. OVERALL MODELS CONTINUE IN PRETTY GOOD AGREEMENT. WILL LEAN TOWARDS GFS FOR DETAILS AS ITS DOING A LITTLE BETTER WITH NEAR TERM SURFACE FEATURES. REGION TO REMAIN IN BROAD SW FLOW ALOFT TODAY AS MID LEVEL SHEAR AXIS SHIFTS ACROSS HIGH PLAINS. SO FAR NOT MUCH HAPPENING IN PCPN DEPARTMENT AS RUC SHOWING HIGH CONDENSATION PRESSURE DEFICITS WITH MAINLY MID LEVEL CIGS. WATER VAPOR INDICATING PLUME OF DEEPER LAYERED RH LIFTING NE WHICH WILL AFFECT AREAS FROM FAR SE ND INTO NW MN DURING DAY. CONDENSATION PRESSURE DEFICITS DO LOWER THIS AREA DURING DAY SO WILL CONTINUE WITH LOW POPS FROM SOUTHERN VALLEY INTO NW MN. PHASE WILL BE TRICKY EARLY THIS MORNING WITH ANY PCPN WHICH DOES FORM. TEMPERATURES CURRENTLY BLO FREEZING HOWEVER APPEARS TO BE A WEAK WARM FRONT ALONG A MOT-JMS-ATY LINE WHICH MAY LIFT TEMPERATURES ABOVE FREEZING AS SURFACE TROUGH APPROACHES. WILL WATCH TEMPERATURE TRENDS BEFORE DETERMINING PHASE HOWEVER ANY PCPN LIKELY TO BE FAIRLY INSIGNIFICANT. FOR AVIATION PURPOSES ZONE OF LOWER CIGS BEHIND COLD FRONT WHICH HAS JUST ENTERED NW ND DROPPING SE AT 25KTS AND MAY REACH FAR NW FA AROUND 12Z. WILL ALSO MONITOR THIS FOR 12Z TAFS AS MODELS DO BRING IN HIGHER 925MB RH VALUES DURING DAY. THERMAL RIDGE OVER FA THIS MORNING SAGS WITH COLD ADVECTION DURING DAY. ALONG WITH POTENTIAL CLOUD COVER AND BEING TOO OPTIMISTIC WITH TEMPERATURES LAST SEVERAL DAYS WILL STAY ON LOW SIDE OF NUMERICAL GUIDANCE. BOUNDARY LOOKS A LITTLE SLOWER EXITING EASTERN FA THIS EVENING. WILL HOLD OFF ON INSERTING POPS BUT DAY CREW WILL NEED TO MONITOR BOUNDARY PROGRESSION. OTHERWISE WEAK RIDGING BUILDS IN OVERNIGHT AND RETURN TO WARM ADVECTION/RETURN FLOW MONDAY AM. ATLEAST PARTIAL CLOUDS AND LACK OF COLD AIR WILL KEEP MINS FROM DROPPING TOO FAR. COLUMN DOES DRY OUT DURING THE DAY MONDAY FOR POTENTIAL SOLAR. COMBINED WITH WARM ADVECTION AND S-SW SURFACE FLOW MAY ACTUALLY SEE TEMPERATURES CLOSER TO AVERAGE. 850MB WARM ADVECTION MAXIMIZED OVER WESTERN FA AT 06Z TUESDAY WHICH SHIFTS INTO VALLEY AREA BY 12Z. PHASE AGAIN WILL BE TRICKY HOWEVER FOR NOW WILL NOT JOSTLE PHASES IN MARGINAL SITUATION. REGION THEN BECOMES SPLIT BETWEEN LOW PRESSURE AREAS AND ENERGY REFOCUSES ACROSS SOUTHERN PLAINS SYSTEM. WILL KEEP LOW POPS GOING WITH BOUNDARY PASSAGE TUESDAY HOWEVER DOESNT LOOK LIKE MUCH OF AN EVENT HERE. PROGRESSIVE PATTERN CONTINUES FOR REMAINDER OF WORK WEEK WITH HIGH PRESSURE WEDNESDAY AND NEXT WAVE AND ASSOCIATED SURFACE BOUNDARY THURSDAY. CURRENT FORECAST HAS THIS IN HAND SO NO SIGNIFICANT CHANGES PLANNED IN LATER PERIODS. && AVIATION...AREA OF IFR/MVFR CIGS ENTERING NW ND NOT SHOWING ANY SIGNS OF SLOWING AND LIKE PAST EVENTS WILL LIKELY SPREAD ACROSS FA FROM NW-SE DURING DAY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ VOELKER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE INDIANAPOLIS IN 1029 AM EST SUN NOV 12 2006 .UPDATE...STRONG 900MB INVERSION STILL HANGING ON OVER INDIANA THIS MORNING. H85 RIDGE MAX IS STILL SLIGHTLY TO OUR WEST WHICH IS CONTRIBUTING TO THE LACK OF CLEARING. RUC SHOWING PLENTY OF MOISTURE BELOW 900MB AND UNTIL THE RIDGE MAX PASSES TO OUR EAST SUBSIDENCE WONT BE STRONG ENOUGH TO FORCE THE INVERSION TO THE GROUND. THE FEW BREAKS IN THE CLOUDS HAVE BEGUN TO FILL IN WHICH WILL ALSO LIMIT DAYTIME HEATING. WITH LITTLE TEMPERATURE ADVECTION BELOW 900MB WOULD NOT EXPECT CLOUDS TO BREAK UP UNTIL THE 18Z-21Z TIMEFRAME. BECAUSE OF THIS WILL SHAVE A DEGREE OR TWO OFF OF DAYTIME HIGHS. UPDATE OUT SHORTLY. && .AVIATION...DISCUSSION FOR 121200Z TAF ISSUANCE. HI PRES CENTERED OVR IL AT 11Z. MVFR CLOUD LINE IS LOCATED ALONG INDIANA ILLINOIS BORDER. SOUNDINGS SHOW STRONG INVERSION PERSISTING UNTIL LATE MORNING/EARLY AFTERNOON WHICH SHOULD KEEP LOW CIGS AROUND UNTIL THEN. 95 PERCENT RH FROM THE NAM AT 925 MB MATCHES UP WELL WITH CURRENT LOW CIGS AND AGREES WITH SOUNDINGS ON TIMING OF VFR. INVERSION SHUD MIX OUT AT ALL SITES BY 17Z AND MIX CIGS TO VFR. && .PREV DISCUSSION...MAIN WEATHER FACTOR TO WORK WITH TODAY WILL BE THE CLOUDS. THIS MORNING SATELLITE PICTURES AND SURFACE OBSERVATIONS SHOW A LINGERING AREA OF LOW CLOUDS OVER MOST OF CENTRAL INDIANA. THESE CLOUDS ARE BEING TRAPPED OVER THE AREA BY AN INVERSION. ONCE THE INVERSION BREAKS MID TO LATE MORNING THE CLOUDS SHOULD MOVE OUT. THE NEXT CLOUD PROBLEM IS AN AREA OF CI THAT IS OVER ILLINOIS MOVING EAST. ONLY THE GFS HAS THIS MOVING INTO INDIANA. WITH ITS PRESENT STEADY MOVEMENT THIS LOOKS GOOD. THE PROBLEM WILL BE WHEN IT DOES MOVE IN HOW DENSE WILL IT BE. AT THE PRESENT TIME IT LOOKS THIN ENOUGH TO GO MOSTLY SUNNY. THE CLOUDS DURING THE MORNING WILL SLOW THE TEMPERATURE INCREASE SOME ALONG WITH ANY CLOUDS THIS AFTERNOON. SO WILL GO TOWARD THE LOWER GUIDANCE HIGHS. HIGH PRESSURE WILL CONTINUE TO BUILD INTO INDIANA DURING THE DAY. THE GFS CONTINUES TO SHOW MID AND HIGH LEVEL MOISTURE OVER INDIANA TONIGHT. WILL GO AT LEAST PARTLY CLOUDY DUE TO THE MOISTURE. WITH THE CLOUDS WILL KEEP MIN TEMPERATURES A LITTLE HIGHER. THE HIGH WILL MOVE EAST OF INDIANA ON MONDAY. THIS WILL ALLOW A WEAK COLD FRONT TO MOVE INTO THE STATE. 850 MB TEMPS SHOW A WARM UP FOR PART OF THE DAY. WILL GO NEAR GUIDANCE FORECAST. DUE TO LACK OF MOISTURE WILL NOT MENTION ANY RAIN WITH THIS FRONT. && IND WATCHES/WARNINGS/ADVISORIES...NONE. $$ UPDATE...SALLY AVIATION...CP PUBLIC...HAINES in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 855 AM EST SUN NOV 12 2006 .UPDATE... SATELLITE IMAGERY THIS MORNING CONTINUES TO SHOW PLENTY OF STRATOCUMULUS CLOUDS ACRS THE FCST AREA. LOCAL RAOBS AND RUC40 SOUNDINGS INDICATE THAT THIS MOISTURE LAYER IS NEAR 900 MB...AND IT IS TRAPPED BENEATH A STRONG INVERSION. WITH A RIDGE OF HIGH PRESSURE FCST TO MOVE ACRS THE AREA TODAY...CLOUDS WILL HAVE A HARD TIME EXITING THE REGION AS WINDS WILL BE FAIRLY LIGHT OVERHEAD. AS A RESULT...THE CLEARING OF THE CLOUDS WILL HAVE TO DEPEND ON THE LATE AUTUMN SUNSHINE IN ORDER TO ERODE THE CLOUD DECK. WILL UPDATE THE ZONES/GRIDS TO KEEP MOSTLY CLOUDY CONDITIONS LONGER THROUGH THE DAY...BUT EVENTUALLY HOPING THAT SKIES BECOME PARTLY CLOUDY LATE. WILL ALSO TWEAK HIGH TEMPERATURES DOWN SOME DUE TO THE LINGERING CLOUD COVER. .PREV DISCUSSION... SHORT TERM... SFC HIGH PRESSURE RIDGE EXTENDING FROM NRN MI TO SRN IL AND MOVG SLOWLY EAST THIS MORNING. WIDESPREAD LOW CLOUDS TRAPPED BENEATH INVERSION BASED AROUND 925MB TO THE EAST OF THE RIDGE SHOULD LINGER OVER THE AREA PAST DAYBREAK WITH A GRADUAL CLEARING FROM W-E DURING THE DAY AS THE RIDGE MOVES INTO WRN OH BY 00Z MON. LOWERED MAXES A FEW DEGS FM PREVIOUS FCST IN AGREEMENT WITH COOLER LATEST MAV/MET FCSTS WHICH SEEM REASONABLE GIVEN WK MIXING AND LINGERING LOW CLOUDS AT LEAST PART OF THE DAY. SKIES SHOULD BE MOSTLY CLEAR THIS EVE AND WINDS LIGHT AS THE RIDGE MOVES SLOWLY EAST OF THE AREA. A SHRTWV OVER THE FOUR CORNERS THIS MORNING IS EXPECTED TO LIFT NE TO THE MS VLY BY MON MORNING. THIS WILL INCREASE THE GRADIENT WITH SOME INCREASE IN HIGH CLOUDS LATE OVER WRN PORTIONS OF THE AREA. HWVR, SHOULD BE DECENT RADIATIONAL COOLING EARLY ACROSS THE ENTIRE AREA CONTG SE MOST OF THE NIGHT. MINS AT OR SLIGHTLY BLO MOS SEEM REASONABLE GIVEN THIS EXPECTATION. LONG TERM... MONDAY THROUGH SATURDAY. HIGH PRESSURE WILL SLIDE EAST ON MONDAY. MODELS CONTINUE TO BRING A WEAKENING FRONTAL BOUNDARY ACROSS THE GREAT LAKES...BUT FORCING WILL DECREASE WITH TIME AND WHAT MSTR EXISTS WITH IT WILL REMAIN MAINLY NORTH OF THE AREA. POPS WERE PULLED BY DAY SHIFT AND WILL CONTINUE WITH THIS THINKING AS AT BEST A SPRINKLE OR 2 MAY OCCUR. THEN ATTENTION TURNS TO SYSTEM ADVERTISED TO ARRIVE SOMETIME IN THE TUES NGT/WEDS TIME FRAME. WIDE VARIETY OF SOLUTIONS COMING OUT OF 00Z RUNS BY 12Z WEDS...WITH ECMWF FURTHEST NORTH ACROSS N IL...TO NAM OVER CNTRL IL...GFS OVER W TENNESSEE...AND UKMET OVER N LOUISIANA. ALL SOLUTIONS HAVE MANY IMPLICATIONS ON AMOUNT OF PRECIP AND CONVECTIVE POTENTIAL. GENERAL CONSENSUS OF MOST MODELS HAVING THE LOW TRACK OVER OR SOUTH OF THE AREA WOULD SUGGEST MINIMAL THUNDER CHANCES...BUT INCREASING CHCS FOR MEASURABLE QPF. CURRENTLY HAVE LOW CHC POPS IN FOR TUES EVE THEN HIGH CHC TUES NGT INTO WEDS. WAS TEMPTED TO INCREASE TO LIKELY ON WEDS BUT IF FURTHER SOUTH SOLUTIONS VERIFY...MAIN PRECIP MAY NOT ARRIVE TILL WEDS NGT/THURS SO WILL LEAVE THINGS ALONE. ALL PRECIP THROUGH THURS SHOULD BE IN THE LIQUID FORM...WITH SNOW BECOMING MORE OF AN ISSUE ON THE BACK SIDE OF THE SYSTEM. BY 00Z FRI MODELS DO COME INTO SLIGHTLY BETTER AGREEMENT ON THE SFC LOW SOMEWHERE FROM NE LK HURON TO LAKE ERIE OR NW OHIO. ANOTHER TROUGH WILL MOVE IN ACROSS SOUTHERN CANADA LATE THURS AND ALLOW FOR THE SYSTEM OVER THE GREAT LAKES TO BE PULLED NORTH ENDING PRECIP CHANCES JUST AS THE COLDER AIR ARRIVES. ANOTHER FRONT MAY BE ASSOCIATED WITH THIS APPROACHING TROUGH IN THE FRI TIME FRAME. ENOUGH MODEL ISSUES THAT FAR OUT TO PRECLUDE PRECIP MENTION. IF SCENARIO WORKED OUT WOULD BE SHOT AT SOMEWHAT COLDER AIR ARRIVING WITH THIS FRONT...BUT NOT SO SURE THIS WILL OCCUR. PLENTY OF TIME TO MONITOR SO WILL KEEP THURS NGT THROUGH SATURDAY DRY WITH TEMPS NEAR OR JUST BELOW NORMAL. AVIATION... SFC HIGH PRES RIDGE EXTENDED FROM CENTRAL MI TO SE IL ATTM. LARGE STRATO CU DECK WAS LOCATED EAST OF THE SFC RIDGE. A COUPLE OF LARGE HOLES HAVE DEVELOPED IN THIS DECK OVER LOWER MICHIGAN AND EXPECT THESE WILL EXPAND INTO NRN INDIANA BY 18Z. REMAINDER OF THE PERIOD SHOULD BE GENERALLY CLOUD FREE OTHER THAN SOME PASSING CIRRUS TODAY AND PSBLY A CIRROSTRATUS DECK MOVG INTO THE AREA FROM THE WEST LATE IN THE PERIOD AS A WKNG SHRTWV/CDFNT APPROACHES. DECENT RADIATIONAL COOLING TONIGHT MAY CAUSE TEMPS TO DROP BELOW CROSSOVER TEMP, HOWEVER MIXING SHOULD BE SUFFICIENT TO PREVENT FOG AND DOUBT MOISTURE DEEP ENOUGH FOR STRATUS SO CONTD VFR. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ UPDATE...HICKMAN LONG TERM...FISHER SHORT TERM/AVIATION...TAYLOR in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 700 AM EST SUN NOV 12 2006 .AVIATION... THE WEAK BUT PERSISTENT BANDING OF SPRINKLES/FLURRIES DETECTED COMING OFF OF SAGINAW BAY AND ALSO CLIPPING AREAS PRIMARILY NEAR THE SOUTHERN TIP OF LAKE HURON OVERNIGHT HAS OVERALL WEAKENED BUT IS STILL DISCERNIBLE IN AVAILABLE RADAR IMAGERY. HARDER TO EXPLAIN IS THE DEGREE OF CLEARING LATE IN THE OVERNIGHT OVER PARTS OF SOUTHEAST MI. BELIEVE THAT THE THINNING/CLEARING IS RELATED AT LEAST IN PART TO RELATIVE SUBSIDENCE BETWEEN THE CONVERGENCE PLUMES ASSOCIATED WITH THE LAKE EFFECT BANDS. THIS MAY ALSO EXPLAIN WHY SOME AREAS ARE TENDING TO FILL BACK IN AGAIN WITH CLOUDS AS THE LAKE EFFECT/CONVERGENCE WEAKENS. THIS WEAKENING TREND IS STILL SUPPORTED BY THE 06Z GFS/NAM AND LATEST RUC. SO...FOR THE TAFS...THE ONLY ISSUE IS IN GETTING RID OF THE LOW CLOUDS. MOST MODEL SOUNDINGS DO LOOK TO WIDEN THE LOW LEVEL TEMPERATURE/DEW POINT SPREAD ENOUGH TO SUGGEST LOSS OF THE OCCASIONAL MAINLY MVFR CEILINGS BY MID DAY...SO HAVE WRITTEN THE TAFS ACCORDINGLY. OTHERWISE...NO CEILINGS...DRY AND VFR AS RIDGE AT THE SURFACE AND ALOFT MOVES OVER THE AREA. && .UPDATE... RECENTLY UPDATED TO REMOVE EARLY MORNING WORDING FROM ZONES AND TO TWEAK FORECAST TODAY MAINLY FOR SKY CONDITIONS THIS MORNING. UNEXPECTED DEGREE AND PERSISTENCE OF THINNING/CLEARING OVER MUCH OF THE EASTERN AND SOUTHERN COUNTIES OF SOUTHEAST MICHIGAN. && .PREV DISCUSSION...ISSUED 358 AM EST SUN NOV 12 2006 SHORT TERM...TODAY AND TONIGHT MODELS IN PRETTY GOOD AGREEMENT AS FOR THE SYNOPTIC PICTURE. SURFACE RIDGE TO PASS SLOWLY EAST ACROSS SOUTHEAST MI TODAY INTO TONIGHT. AT 500 MB...MEANWHILE...SHORTWAVE RIDGE OVERHEAD TODAY TO RETREAT EAST TONIGHT. EXCEPT AS NOTED BELOW...OVERALL DESCENT SEEN IN OMEGA FIELDS TODAY INTO TONIGHT...WITH QVECTOR CONVERGENCE ALSO INDICATING MOSTLY DIVERGENCE/SUBSIDENCE. 850 TO 500 MB MOISTURE RATHER MEAGER THROUGH TONIGHT. INCREASING CIRRUS...THOUGH...LIKELY TO BE SEEN MAINLY LATE TONIGHT BEHIND RIDGE ALOFT. LOW LEVEL MOISTURE...AS AT 925 MB...EXPECTED TO DIMINISH TODAY. THE EXCEPTION TO NO WEATHER IS THE OVERNIGHT SPRINKLES AND FLURRIES SEEN OVER MUCH OF THE FORECAST AREA...LARGELY RELATED TO LAKE EFFECT FROM NORTH TO NORTHEAST FLOW OFF OF LAKE HURON. DELTA TS INTO THE LOWER TEENS EARLIER IN THE NIGHT SHOULD LESSEN STEADILY THIS MORNING AS 850 MB TEMPERATURES WARM BEHIND THE BRIEF THERMAL TROUGH. NAM/RUC AND GFS SHOW GOOD LOW LEVEL CONVERGENCE...TENDING TO MAXIMIZE AROUND 06Z...ALSO ON THE WANE THIS MORNING. NAM ALSO SHOWS MODEST 950 MB OMEGA LIFT...MAINLY IN THE THUMB...WANING THIS MORNING. WILL CARRY MENTION OF SPRINKLES OR FLURRIES INTO THE MORNING FOR MOST OF THE AREA...THEN RIDGE OVERHEAD THIS AFTERNOON SHOULD KILL OFF ANY MORE POSSIBILITY OF THIS TRACE PRECIPITATION. PERSISTENCE OF SPRINKLES...AS OPPOSED TO FLURRIES...SEEMS RELATED TO SHALLOW DEPTH OF MOISTURE AND THUS VERY POOR ICE NUCLEATION POTENTIAL...AS PER MODEL SOUNDINGS. AS FOR CLOUD COVER TODAY...MOST MODELS INDICATE LESSENING BY AFTERNOON...AND WILL SO INDICATE. SATELLITE IMAGERY ALREADY SHOWING SOME THIN SPOTS/HOLES IN THE CLOUD COVER. DAYTIME MIXING SHOULD AID IN CLOUD COVER DECREASE. LONG TERM...MONDAY THROUGH SUNDAY CONFIDENCE IS INCREASING FOR A POTENT STORM TO IMPACT THE REGION FOR MID WEEK...HOWEVER...PREDICTABILITY OF THE EVENTUAL UPPER FLOW REGIME ACROSS THE CONUS REMAINS BELOW AVERAGE. SATELLITE DERIVED WINDS IN THE EASTERN PACIFIC AS OF 03Z WERE AVERAGING AROUND 120KTS WITH A DEVELOPING JET STREAK APPROACHING 150KTS EAST OF 150W IN BETWEEN 40-50N. GLOBAL MODELS SEEM TO HAVE INITIALIZED THE PACIFIC JET ORIENTATION AND GENERAL STRENGTH AS THE ECMWF APPEARS TO HAVE PICKED UP THE JET STREAK EARLIER THAN THE OTHER OPERATIONAL GLOBAL MODELS. THIS FEATURE(S) WILL BE OUR FORECAST CHALLENGE FOR THIS UPCOMING WEEK. BEGINNING WITH MONDAY...LONG WAVE TROUGH CURRENTLY PROGRESSING THROUGH THE INTERMOUNTAIN WEST AND EMBEDDED SHORT WAVE ACROSS THE FOUR CORNERS WILL LIFT NORTHEAST THROUGH THE DAY AS SHORT WAVE RIDGE AND SURFACE HIGH PRECEDING IT SLIDES FURTHER EAST. WHILE A GOOD AERIAL COVERAGE OF PRECIP IS EXPECTED TO ACCOMPANY THIS FEATURE INITIALLY...DECREASING THERMAL GRADIENT IN THE LOW-MID LEVELS ACROSS THE MID-UPPER MISSISSIPPI RIVER VALLEY AND BEST UPPER SUPPORT WILL LIFT INTO CANADA AND REDUCE THE CHANCES OF PRECIP FOR THE CWA. IN FACT...HARD TO FIND A MODEL THAT PRINTS ANY QPF ACROSS THE CWA. DO NOT FEEL COMPELLED TO REMOVE POPS COMPLETELY AND WILL RETAIN THE CURRENT FORECAST WITH 20% POPS ALONG AND NORTH OF 8-MILE WITH 30% POPS AROUND THE TRI CITIES. THEN A BRIEF RESPITE MONDAY NIGHT INTO TUESDAY AS WEAK SURFACE HIGH AND SHORT WAVE RIDGE AXIS MOVES ACROSS THE GREAT LAKES. HOWEVER... LOW LEVEL MOISTURE REMAINS RATHER HIGH AS OBSERVED IN THE GFS/NAM/WRF-HEMI SOUNDINGS HENCE THE PERCENT CLOUD COVER WILL REMAIN RATHER HIGH THROUGH EARLY TUESDAY MORNING. POTENT PACIFIC JET COMES ASHORE AND DIVES SOUTHEAST INTO THE THE FOUR CORNERS REGION TUESDAY NIGHT WITH SURFACE LOW DEVELOPING IN THE VICINITY OF THE PANHANDLE OF TEXAS. DEPENDING ON HOW THIS PATTERN UNFOLDS ACROSS THE CONUS...TRENDS IN THE GLOBAL MODELS SUGGEST UPPER PATTERN QUICKLY BECOMES NEGATIVELY TILTED AS GULF OF MEXICO MOISTURE ADVANCES NORTHWARD WEDNESDAY-WEDNESDAY NIGHT. CROSS SECTIONS FROM THE GFS SHOW A RATHER POTENT PETTERSSEN 2-D FGEN LAYER BETWEEN 850-700MB WITH AN INCREASED SLANTWISE INSTABILITY (INCLUDING DEPTH) JUST ABOVE THIS LAYER AS SUGGESTED IN THE LOWERING EPV/S ACROSS THE CWA. COULD SEE A BAND(S) OF HEAVY RAIN AND THUNDER WEDNESDAY AFTERNOON INTO THURSDAY MORNING...THIS WILL NEED TO MONITORED CLOSELY AS PWATS ARE EXPECTED TO CLIMB IN EXCESS OF 1 INCH. LOW BECOMES VERTICALLY STACKED ACROSS THE STATE THROUGH THURSDAY WITH A SLOW RETREAT NORTHWARD THROUGH THE END OF THIS WEEK. 850MB TEMPS DROP BACK TOWARD THE NEGATIVE TERRITORY AND PERHAPS EVEN LOWER INTO THE WEEKEND AS UPPER FLOW AMPLIFIES TOWARD A RIDGE ACROSS THE ROCKIES AND A TROUGH ACROSS THE GREAT LAKES/MIDDLE ATLANTIC COAST. THIS SETS THE STAGE FOR THE CHANCE OF SNOW SHOWERS FROM THE COLD/MOIST CYCLONIC FLOW AND CONTRIBUTIONS FROM LAKE MICHIGAN. WILL GO LOWER THAN MEX NUMBERS AND ADD POPS FOR SNOW THROUGH AT LEAST NEXT SATURDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421... NEARSHORE WATERS FROM PORT AUSTIN TO PORT HURON... UNTIL 5 PM SUNDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION AND UPDATE...DWD SHORT TERM...DWD LONG TERM....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 GREENVILLE-SPARTANBURG SC 1035 AM EST SUN NOV 12 2006 .SHORT TERM /REST OF TODAY/... UPPER LOW ABOUT WHERE IT WAS EXPECTED TO BE BASED ON PREVIOUS MODEL RUNS THIS MORNING...OVER THE NORTH CAROLINA PIEDMONT. SAID FEATURE SHOULD CONTINUE TO MOVE SOUTH AND EAST WITH TIME. SURFACE FRONTAL BOUNDARY AT THE COAST. SATELLITE IMAGERY SHOWS EXTENSIVE CLOUDINESS HUGGING THE TENNESSEE BORDER AREAS...AND SOME OF THE INTERIOR MOUNTAINS BUT MOST OF THE NON-TERRAIN AREAS MOSTLY CLEAR. MORNING OBSERVATIONS FROM THE MOUNTAINS REVEALED A LIGHT SNOW FELL IN THE VERY LATE HOURS OVERNIGHT FOR THE VERY HIGHER ELEVATIONS...WITH ONE INCH REPORTED FROM BEECH MOUNTAIN...MOUNT MITCHELL...GRANDFATHER AND AS FAR SOUTH AS FLAT TOP MOUNTAIN IN SOUTHEAST BUNCOMBE COUNTY. ALMOST NO SNOW REPORTED FROM THE VALLEYS. HOWEVER...LAPS SOUNDINGS AND FORECAST SOUNDINGS REVEAL THE SATURATED LAYER IS NOT VERY DEEP AND THE 85H TEMPERATURES SHOULD BE RISING THROUGH THE AFTERNOON. SATELLITE TRENDS REVEAL SLOW EROSION OF THE ANCHORED CLOUD DECK HAS ALREADY BEGUN...BUT THE LOW CLOUDS MAY HANG ON FOR MOST OF THE AFTERNOON. SO...ANY LINGERING SNOW AT THIS HOUR SHOULD TRANSITION TO ALL RAIN BY EARLY AFTERNOON. NEITHER RUC NOR 06Z NAM/WRF PRODUCES MUCH MORE ADDITIONAL PRECIPITATION FOR THE TENNESSEE BORDER AREAS. WE WILL HOLD ON TO ISOLATED RAIN SHOWERS FOR THE NORTHERN MOUNTAINS...HOWEVER...THIS AFTERNOON. MOUNTAIN WINDS HAVE GUSTED AS HIGH AS 40 TO 45 MPH SO FAR; KAVL JUST HAD A WIND GUST TO 43 MPH. THE BETTER MIXING HAS ALSO RESULTED IN STRONG GUSTS FOR THE FOOTHILLS AND PIEDMONT; KCLT RECENTLY GUSTED TO 31 MPH. WITH TIME...THE WINDS THROUGH THE ATMOSPHERIC COLUMN SHOULD WANE...AND ANY RESIDUAL COLD ADVECTION WILL BE REPLACED BY WARM ADVECTION. FOR NOW...WILL NOT PLAN ANY CHANGES TO CURRENT WIND ADVISORY/LAKE WIND ADVISORY PRODUCTS FOR THE HIGHER TERRAIN. BASED ON CHANGES WE MADE TO THE FOOTHILL/PIEDMONT WINDS FOR THE AFTERNOON...WILL HAVE TO CARVE OUT SOME OF TEH LARGER ZONE GROUPINGS TO INCREASE TO BREEZY BUT WILL HOLD OFF ON ANY EXTENSION OF THE LAKE WIND ADVISORY AND MONITOR FOR POTENTIAL UPDATES LATER. TEMPERATURES HAVE RISEN STEADILY THIS MORNING...BUT LOW LEVEL THICKNESS SCHEME SUPPORTS NO MORE THAN LOWER 60S FOR THE CWFA...AND NORTHEAST CWFA WILL BE IN THE OUTER CIRCULATION OF THE UPPER LOW FOR A WHILE YET. MOUNTAINS MAY SEE MINIMAL MERCURY CLIMBS TODAY. WILL LOWER MAXES CWFA-WIDE...TO MID/UPPER 50S FOOTHILLS AND PIEDMONT...AND HOLD ON TO LOWER 60S ONLY FOR THE EXTREME SOUTHWEST CWFA. && .PREV DISCUSSION... /ISSUED 255 AM EST SUN NOV 12 2006/ SHORT TERM /TODAY THROUGH TUESDAY NIGHT/... PCPN CHANCES THIS MORNING WILL BE LIMITED TO JUST THE NC MTNS...AND MAINLY THE WESTERN SLOPES AND HIGHER ELEVATIONS AS A PERIOD OF BRISK UPSLOPE FLOW CONTINUES. LLVL MOISTURE IS QUITE SHALLOW AND THE TEMPERATURES WITHIN THIS MOIST LAYER...MARGINALLY COLD...PERHAPS -2C AT BEST. SO...A MIX OF SPOTTY LIGHT RAIN/SNOW SHOWERS AND PATCHY DRIZZLE/FREEZING DRIZZLE WILL BE SEEN THIS MORNING WITH PROGRESSIVE LLVL DRYING SLATED FOR THIS AFTERNOON. BASED ON PALTRY MAGNITUDE OF EXPECTED WINTER WX THREAT AND RECENT RECORD WARMTH...LITTLE IF ANY SNOW OR ICE ACCUMULATION IS EXPECTED. WITHIN THE SUBSIDING AIRMASS TODAY...GUSTY WINDS WILL CONTINUE. 40-50 MPH GUSTS ARE EXPECTED ACRS FAVORED AREAS OF THE NC MTNS WITH CONDITIONS VARYING BETWEEN SOME DEGREE OF WINDY AND BREEZY ELSEWHERE. PRESSURE GRADIENT REMAINS UP TONIGHT...SO A MIXED AIRMASS WILL CONTINUE UNDER MAINLY CLEAR SKIES AS S/WV RIDGING ALOFT BUILDS A TOP THE CWFA. SHORT WAVE RIDGE REMAINS ACROSS THE AREA MONDAY. THE RIDGE MOVES EAST MONDAY NIGHT AS WEAK SHORT WAVE MOVES THRU INTRODUCING NEAR ZONAL FLOW AND MORE WEAK SHORT WAVES FOR TUESDAY. STRONG WAVES DIG A TROF OVER THE CENTRAL PART OF THE COUNTRY TUESDAY NIGHT WHILE OUR FLOW BECOMES SOUTHWESTERLY. AT THE SURFACE...CWFA WILL BE BETWEEN DEPARTING LOW AND HIGH PRESSURE MOVING IN FROM THE WEST. SHORT WAVE WILL BRING SOME CIRRUS FOR MONDAY AFTERNOON AND EVENING...BUT LOW LEVELS VERY DRY. THE DRY LOW LEVELS CONTINUE TUESDAY...BUT COULD BE QUITE A BIT OF CIRRUS STREAMING EASTWARD SO PARTLY CLOUDY SKIES. NEXT SYSTEM APPROACHES THE AREA TUESDAY NIGHT. NAM BRINGS PRECIP TO THE MOUNTAINS...WHILE GFS KEEPS IT TO THE WEST. SHORT RANGE ENSEMBLES SHOW SOME PRECIP POSSIBLE OVER THE MOUNTAINS SIMILAR TO NAM...BUT PLUME DIAGRAMS SHOW MANY DRY MEMBERS. MEMBERS SHOWING PRECIP...EXCEPT FOR ONE...HAVE ONLY LIGHT AMOUNTS. CANADIAN IS EVEN SLOWER THAN THE GFS. THEREFORE HAVE DECIDED TO SLOW PRECIP WITH ONLY CHC TO SLIGHT CHC OVER THE MOUNTAINS. HIGHS RETURN TO ABOVE NORMAL LEVELS WITH RIDGING ON MONDAY. LOWS BELOW NORMAL MONDAY NIGHT WITH SOMEWHAT DECENT RADIATIONAL CONDITIONS. HIGHS ABOVE NORMAL AGAIN TUESDAY...BUT A LITTLE LOWER WITH SLIGHTLY LOWER THICKNESSES AND INCREASING CIRRUS. LOWS TUESDAY NIGHT NEAR NORMAL. LONG TERM /WEDNESDAY THROUGH SATURDAY/... GFS AND CANADIAN SLOWING SYSTEM FOR WEDNESDAY. STILL LOOKS LIKE A DECENT CHANCE OF PRECIP OVER THE MOUNTAINS WEDNESDAY...SO WILL LEAVE POP AS IS. WILL HAVE TO WATCH THE DEVELOPMENT OF THIS SYSTEM. GFS SHOWS QUITE A BIT OF FORCING WITH HIGH SHEAR. FORECAST INSTABILITY QUITE LOW OVER OUR CWFA...BUT THIS FITS THE PATTERN FOR A FALL SEVERE WEATHER EPISODE. THAT SAID...STILL TOO EARLY TO FOR BANDWAGON JUMPING. SCATTERED SHOWERS SHOULD CONTINUE ACROSS THE NC MOUNTAINS...AND NORTHERN NC FOOTHILLS AND PIEDMONT THROUGH THURSDAY MORNING AS DRY SLOT MOVES IN TO THE AREA FROM THE SOUTHWEST. A DECENT THICKNESS PACKING ASSOCIATED WITH UPPER TROF WILL CROSS THE AREA WEDNESDAY AND A DEEP THERMAL TROF WILL SLOWLY TRANSIT THE CWFA THROUGH FRIDAY. TEMPERATURES ASSOCIATED WITH THIS SCENARIO WILL GENERALLY BE ON THE ORDER OF 10 DEGREES BELOW NORMAL THURSDAY THROUGH SATURDAY. AVIATION... LINGERING STRATOCU ACRS THE PIEDMONT WILL CONTINUE TO SCOUR DURING THE PRE-DAWN HOURS...WITH UPVALLEY CLOUDS AT KAVL LINGERING A LITTLE LONGER...PERHAPS UNTIL 12 UTC. OTHERWISE...SOLE CONCERN FOR THE 06 UTC TAF PACKAGE WILL BE GUSTY NW WINDS WHICH WILL BE SEEN PRETTY MUCH ALL DAY. EXPECT WIND GUSTS TO ABOUT 20 KTS ACRS LOWER ELEVATIONS AND TO ABOUT 30 AT KAVL...DIMINISHING BY THIS EVENING. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...LAKE WIND ADVISORY FOR GAZ010-017 UNTIL 7 PM SUNDAY. NC...WIND ADVISORY FOR NCZ033-034-048>050-052>055-059-063>066-501- 503-505-507-509 UNTIL 7 PM SUNDAY. ...LAKE WIND ADVISORY FOR NCZ051-058-062 UNTIL 7 PM SUNDAY. SC...LAKE WIND ADVISORY FOR SCZ001 UNTIL 7 PM SUNDAY. ...WIND ADVISORY FOR SCZ002-003 UNTIL 7 PM SUNDAY. && $$ SHORT TERM...44 sc AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 950 AM EST SUN NOV 12 2006 .SHORT TERM /REST OF TODAY/... LOW PRES ALONG THE FRONT CONTINUES TO DRIFT SLOWLY NE THRU EASTERN NC THIS MORNING WITH ONGOING NEGATIVE TILT PULLING LIGHT/MOD RAIN BACK ACROSS MUCH OF THE PIEDMONT ATTM. EXPECT AS THE SYSTEM WORKS NE THIS AFTERNOON WILL SEE DRY AIR SLOWLY CUTOFF -RA ON THE SW SIDE AS MID LEVEL AXIS OF CONVERGENCE PIVOTS MORE INTO THE NERN ZONES WHERE WILL KEEP CAT/LIKELY POPS GOING. ELSW ABRUPT DROPOFF IN RH LIKELY ALONG THE SOUTHERN BLUE RIDGE PER NW DOWNSLOPE/SUBSIDENCE BEFORE GETTING BACK INTO MORE UPSLOPISH MOISTURE WESTERN SLOPES. HOWEVER GIVEN FLOW ALOFT MORE NORTHERLY AND BEST MOISTURE OUT WITH COASTAL LOW APPEARS EVEN UPSLOPE MIX OF PRECIP LIKELY VERY LIGHT/SPOTTY THIS AFTERNOON. THIS SEEN IN MOST MODEL OUTPUT ESPCLY LATEST WRF/NMM AND RUC WHICH HAVE VERY LIMITED COVERAGE. THUS PLAN TO CUT POPS TO CHANCE WESTERN SLOPES AND GO WITH LITTLE OR NO PRECIP FROM THE NEW RIVER VALLEY SOUTH. WINDS HAVE BEEN BELOW ADVISORY LEVELS SO FAR WITH WAVE SLOW TO MOVE NE/DEEPEN AND RATHER WEAK 85H JET. EXPECT ONCE ITS GETS A BIT FARTHER EAST AND MIXING INCREASES WILL SEE RIDGES PICK UP ALTHO FORECAST PRES RISES NOT ALL THAT GREAT FOR THE AFTERNOON. OTRW SOME SMALL ADJUSTS TO TEMPS SINCE APPEARS ONLY SLIGHT RISES AT BEST MOST AREAS THRU THE AFTERNOON. && .PREV DISCUSSION... (ISSUED 647 AM EST SUN NOV 12 2006) AVIATION... BLF WILL START OUT WITH IFR CONDITIONS THIS MORNING DUE TO STRONG LOW LEVEL WINS PUSHING MOISTURE UP THE MOUNTAINS. CEILINGS WILL IMPROVE GRADULLY WITH CEILINGS AT BLF BECOMING MVFR BY THE END OF THE DAY. LOW PRESSURE DEVELOPING IN NORTH CAROLINA WILL KEEP VFR CLOUDS IN OVER LYH THROUGH THIS EVENING. CLOUDS AT ROA AND DAN WILL BECOME SCATTERED AS THE DRY SLOT ADVANCES INTO THE REGION. WINDS WILL BE GUSTY TODAY OUT OF THE NORTH TO NORTHWEST. AS THE SURFACE LOW DEEPENS THE WINDS WILL INCREASE...ESPECIALLY EAST OF THE MOUNTAINS. PREV DISCUSSION... (ISSUED 221 AM EST SUN NOV 12 2006) SHORT TERM /TODAY/... DECIDED TO KEEP WIND ADVISORY UP TODAY FOR NORTHWEST MOUNTAINS OF NC NORTHWARD THRU GRAYSON...CARROL AND FLOYD COUNTIES. COLD FRONT CONTINUES ITS MARCH EAST TO THE ATLANTIC THIS MORNING. CLOSED LOW DEVELOPS ACROSS EASTERN VA/NC AND LIFTS TOWARDS NEW ENGLAND TONIGHT. BAND OF SHOWERS AND EMBEDDED THUNDERSTORMS MOVING ACROSS EASTERN THIRD THIS MORNING. WRAP AROUND LOW MOISTURE WILL CLIP THE FAR EAST TODAY AND EXPECT UPSLOPE CLOUDS IN THE WEST. MOST OF PCPN WILL BE LIQUID BUT SOME LIGHT SNOW IS POSSIBLE IN THE HIGHEST ELEVATION. NOT AS IMPRESSED WITH LIMITED MOISTURE AND MORE NORTHERLY WIND COMPONENT. PLAYED TEMPERATURES CLOSE TO MAV GUID. LONG TERM /TONIGHT THROUGH SATURDAY/... CLOSED LOW MOVES OFF THE COAST THEN TOWARD NEW ENGLAND TONIGHT AND MONDAY. WINDS WILL REMAIN STRONG AROUND THE LOW THIS EVENING...THEN START TO DIMINISH AS THE LOW MOVES FURTHER OFFSHORE TONIGHT. SURFACE WINDS WILL BE MUCH LIGHTER BY MONDAY AFTERNOON WITH HIGH PRESSURE APPROACHING AREA. THE Q-VECTOR FORCING AND DEFORMATION AREA STAY JUST EAST OF THE COUNTY WARNING AREA TONIGHT. HOWEVER CLOUDS WILL HOLD IN ACROSS THE EASTERN COUNTY WARNING AREA THROUGH MONDAY AFTERNOON. WENT WARMER THAN MET GUIDANCE ON MONDAY WHICH KEEPS THE PIEDMONT CLOUDY ALL DAY AND COOLER THAN MAV GUIDANCE WHICH HAS MORE SUN IN THE MORNING. COLD AIR IS VERY SHALLOW AND WARM AIR ADVECTION MODERATES THE AIRMASS WITH 850 MB TEMPERATURES WELL AABOVE ZERO BY MONDAY MORNING. SINCE LOW LEVEL WINDS ARE FROM THE NORTH THE UPSLOPE COMPONENT IS NOT THAT GOOD AND WITH SUCH SHALLOW MOISTURE AND COLD AIR AND VERY LIGHT QPF AMOUNTS WILL KEEP JUST LIGHT ANOUMTS OF RAIN AND SNOW IN SOUTHEAST WEST VIRIGINA THROUGH EARLY MONDAY. THE NEXT DEEP TROF DIGGING INTO THE MISSISSIPPI VALLEY ON TUESDAY AND WEDNESDAY WILL BEGIN TO BACK THE LOW LEVELS WINDS. THE LOW LEVEL SOUTHWEST FLOW ON TUESDAY WILL RESULT IN ABOVE NORMAL HIGH TEMPERATURES. MID AND HIGH LEVEL RELATIVE HUMIDITY AND CLOUDS MOVE INTO THE AREA AHEAD OF THIS SYSTEM ON TUESDAY NIGHT. BY WEDNESDAY NIGHT A STRONG LOW LEVEL JET OUT OF THE SOUTHEAST WILL BRING ABUNDANT MOISTURE OFF THE ATLANTIC. THE GOOD DYNAMICS AND UPPER DIFFLUENCE WEDNESDAY NIGHT STILL SUPPORT RAIN SO NO CHANGE NEEDED TO THE FORECAST..EXCEPT WILL INCREASE WINDS SPEEDS A BIT. AVIATION... COLD FRONT WILL EXIT CWA EARLY THIS MORNING. IN WAKE OF FRONT... WINDS WILL BECOME INCREASINGLY GUSTY THIS MORNING WITH SECONDARY PUSH OF WIND ALOFT GIVEN COLD ADVECTION. UPSLOPE FLOW COMBINED WITH LOW LEVEL MOISTURE AND COLD AIR MAY CREATE LOW CLOUDS AND SOME SNOW SHOWERS IN THE NORTHWEST WESTERN AREAS. LOW CLOUD DECK (MVFR/IFR) IN THE WEST WILL BE SLOW TO IMPROVE TODAY...WHILE IN THE EAST DOWNSLOPE FLOW SHOULD ALLOW FOR SOME BREAKS BY LATE MORNING. MVFR/IFR SHOWERS ARE POSSIBLE IN THE FAR EAST TODAY WITH WRAPAROUND PRECIP BAND AS UPPER LOW CLOSES OFF NEARBY. GUSTY AFTERNOON WINDS ARE POSSIBLE ...WITH POTENTIAL FOR GUSTS IN EXCESS OF 40KTS ACRS THE HIGHER ELEVATIONS. WINDS WILL DIMINISH TONIGHT WITH VFR CONDITIONS PREVAILING. MOUNTAIN OBSCURATIONS ARE POSSIBLE TODAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WIND ADVISORY FOR VAZ015>017 UNTIL 7 PM SUNDAY. NC...WIND ADVISORY FOR NCZ001-002-018 UNTIL 7 PM SUNDAY. WV...NONE. && $$ JH va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 1230 PM EST SUN NOV 12 2006 .AVIATION... MAIN AVIATION CONCERN FOR THIS TAF PACKAGE IS HOW FAST PESKY MVFR STRATOCUMULUS DECK WILL ERODE. STRATOCUMULUS DECK WAS NEARLY STUCK ACRS THE REGION AS A RIDGE OF HIGH PRESSURE FROM THE SFC THROUGH 850 MB WAS PROVIDING FOR FAIRLY LIGHT WIND REGIME THROUGH THE LAYER. AS A RESULT...ONLY DAYTIME SUNSHINE WILL BE THE KEY FACTOR ON DISSIPATING THE DECK. LATEST VISIBLE SATELLITE IMAGERY WAS INDICATING THAT THIS INDEED WAS OCCURRING ACRS THE WEST. WILL ONLY EMPLOY A SCATTERED DECK AT KSBN WITH TAF ISSUANCE. FARTHER EAST...THE EROSION PROCESS HAS BEEN MUCH SLOWER. THEREFORE...WILL HAVE TO FCST A BKN MVFR DECK AT KFWA FOR AT LEAST THROUGH LATE AFTN. FOR TONIGHT...SFC RIDGE OF HIGH PRESSURE WILL MOVE SLOWLY EAST. A WEAK COLD FRONT ACRS THE PLAINS THIS AFTN WILL MOVE INTO THE WRN GREAT LAKES BY LATE MONDAY AFTN. AS THIS FEATURE APPROACHES...MID AND HIGH LVL CLOUDINESS WILL INCREASE. && .PREV DISCUSSION... UPDATE... SATELLITE IMAGERY THIS MORNING CONTINUES TO SHOW PLENTY OF STRATOCUMULUS CLOUDS ACRS THE FCST AREA. LOCAL RAOBS AND RUC40 SOUNDINGS INDICATE THAT THIS MOISTURE LAYER IS NEAR 900 MB...AND IT IS TRAPPED BENEATH A STRONG INVERSION. WITH A RIDGE OF HIGH PRESSURE FCST TO MOVE ACRS THE AREA TODAY...CLOUDS WILL HAVE A HARD TIME EXITING THE REGION AS WINDS WILL BE FAIRLY LIGHT OVERHEAD. AS A RESULT...THE CLEARING OF THE CLOUDS WILL HAVE TO DEPEND ON THE LATE AUTUMN SUNSHINE IN ORDER TO ERODE THE CLOUD DECK. WILL UPDATE THE ZONES/GRIDS TO KEEP MOSTLY CLOUDY CONDITIONS LONGER THROUGH THE DAY...BUT EVENTUALLY HOPING THAT SKIES BECOME PARTLY CLOUDY LATE. WILL ALSO TWEAK HIGH TEMPERATURES DOWN SOME DUE TO THE LINGERING CLOUD COVER. SHORT TERM... SFC HIGH PRESSURE RIDGE EXTENDING FROM NRN MI TO SRN IL AND MOVG SLOWLY EAST THIS MORNING. WIDESPREAD LOW CLOUDS TRAPPED BENEATH INVERSION BASED AROUND 925MB TO THE EAST OF THE RIDGE SHOULD LINGER OVER THE AREA PAST DAYBREAK WITH A GRADUAL CLEARING FROM W-E DURING THE DAY AS THE RIDGE MOVES INTO WRN OH BY 00Z MON. LOWERED MAXES A FEW DEGS FM PREVIOUS FCST IN AGREEMENT WITH COOLER LATEST MAV/MET FCSTS WHICH SEEM REASONABLE GIVEN WK MIXING AND LINGERING LOW CLOUDS AT LEAST PART OF THE DAY. SKIES SHOULD BE MOSTLY CLEAR THIS EVE AND WINDS LIGHT AS THE RIDGE MOVES SLOWLY EAST OF THE AREA. A SHRTWV OVER THE FOUR CORNERS THIS MORNING IS EXPECTED TO LIFT NE TO THE MS VLY BY MON MORNING. THIS WILL INCREASE THE GRADIENT WITH SOME INCREASE IN HIGH CLOUDS LATE OVER WRN PORTIONS OF THE AREA. HWVR, SHOULD BE DECENT RADIATIONAL COOLING EARLY ACROSS THE ENTIRE AREA CONTG SE MOST OF THE NIGHT. MINS AT OR SLIGHTLY BLO MOS SEEM REASONABLE GIVEN THIS EXPECTATION. LONG TERM... MONDAY THROUGH SATURDAY. HIGH PRESSURE WILL SLIDE EAST ON MONDAY. MODELS CONTINUE TO BRING A WEAKENING FRONTAL BOUNDARY ACROSS THE GREAT LAKES...BUT FORCING WILL DECREASE WITH TIME AND WHAT MSTR EXISTS WITH IT WILL REMAIN MAINLY NORTH OF THE AREA. POPS WERE PULLED BY DAY SHIFT AND WILL CONTINUE WITH THIS THINKING AS AT BEST A SPRINKLE OR 2 MAY OCCUR. THEN ATTENTION TURNS TO SYSTEM ADVERTISED TO ARRIVE SOMETIME IN THE TUES NGT/WEDS TIME FRAME. WIDE VARIETY OF SOLUTIONS COMING OUT OF 00Z RUNS BY 12Z WEDS...WITH ECMWF FURTHEST NORTH ACROSS N IL...TO NAM OVER CNTRL IL...GFS OVER W TENNESSEE...AND UKMET OVER N LOUISIANA. ALL SOLUTIONS HAVE MANY IMPLICATIONS ON AMOUNT OF PRECIP AND CONVECTIVE POTENTIAL. GENERAL CONSENSUS OF MOST MODELS HAVING THE LOW TRACK OVER OR SOUTH OF THE AREA WOULD SUGGEST MINIMAL THUNDER CHANCES...BUT INCREASING CHCS FOR MEASURABLE QPF. CURRENTLY HAVE LOW CHC POPS IN FOR TUES EVE THEN HIGH CHC TUES NGT INTO WEDS. WAS TEMPTED TO INCREASE TO LIKELY ON WEDS BUT IF FURTHER SOUTH SOLUTIONS VERIFY...MAIN PRECIP MAY NOT ARRIVE TILL WEDS NGT/THURS SO WILL LEAVE THINGS ALONE. ALL PRECIP THROUGH THURS SHOULD BE IN THE LIQUID FORM...WITH SNOW BECOMING MORE OF AN ISSUE ON THE BACK SIDE OF THE SYSTEM. BY 00Z FRI MODELS DO COME INTO SLIGHTLY BETTER AGREEMENT ON THE SFC LOW SOMEWHERE FROM NE LK HURON TO LAKE ERIE OR NW OHIO. ANOTHER TROUGH WILL MOVE IN ACROSS SOUTHERN CANADA LATE THURS AND ALLOW FOR THE SYSTEM OVER THE GREAT LAKES TO BE PULLED NORTH ENDING PRECIP CHANCES JUST AS THE COLDER AIR ARRIVES. ANOTHER FRONT MAY BE ASSOCIATED WITH THIS APPROACHING TROUGH IN THE FRI TIME FRAME. ENOUGH MODEL ISSUES THAT FAR OUT TO PRECLUDE PRECIP MENTION. IF SCENARIO WORKED OUT WOULD BE SHOT AT SOMEWHAT COLDER AIR ARRIVING WITH THIS FRONT...BUT NOT SO SURE THIS WILL OCCUR. PLENTY OF TIME TO MONITOR SO WILL KEEP THURS NGT THROUGH SATURDAY DRY WITH TEMPS NEAR OR JUST BELOW NORMAL. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ AVIATION/UPDATE...HICKMAN SHORT TERM...TAYLOR LONG TERM...FISHER in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DODGE CITY KS 305 PM CST SUN NOV 12 2006 .DISCUSSION... DAYS 1-2... THE MAIN FORECAST CONCERN FOR THE SHORT TERM ARE THE CHANCES FOR PRECIP TONIGHT AND TUESDAY AFTERNOON, ALONG WITH TEMPERATURES. THE UPPER TROUGH AXIS THAT WAS OVER THE FOUR CORNERS REGION AT 12Z HAS PROGRESSED INTO COLORADO, AND SHOULD CONTINUE TO MOVE ACROSS THE PLAINS TONIGHT. THE TROUGH HAS BROUGHT PLENTY OF UVV, AND LIGHT ECHOES HAVE SPREAD ACROSS OUR RADAR SCOPE IN THE LAST FEW HOURS. HOWEVER, TEMPERATURE DEWPOINT SPREADS ARE STILL GREATER THAN 20 DEGREES AT THE SFC IN MOST LOCATIONS, AND THE 850MB OBS FROM THIS MORNING SHOW SIMILAR PATHETIC MOISTURE. MOST OF THE ACTIVITY HAS BEEN IN THE MID LEVELS AND LITTLE IF ANY IS REACHING THE GROUND. TEMPS SHOULD BE COOLING OFF TONIGHT THOUGH, AND RUC MODEL SOUNDINGS ARE OPTIMISTIC ABOUT OUR NORTHERN LOCATIONS GETTING ENOUGH MOISTURE IN THE COLUMN FOR SOMETHING TO REACH THE GROUND. WILL KEEP SLIGHT/LOW CHANCE POPS GOING FOR LIGHT RAIN UNTIL MIDNIGHT, WHEN THE TROUGH AXIS AND SFC FRONT SHOULD BE PAST US. CLOUDS SHOULD START TO BREAK UP LATER TONIGHT AS THE TROUGH AXIS MOVES EAST AND SUBSIDENCE SETS IN. WITH THE BREAKS IN CLOUDS, DIMINISHING WINDS, AND LOW DEWPOINTS, LOWS TONIGHT SHOULD DROP DOWN INTO THE UPPER 20S TO LOW 30S. THE LEE SFC TROUGH SHOULD RAPIDLY RE-DEVELOP TOMORROW, WITH SOUTHERLY WINDS. THE MODELS HAVE STRONG RH AT HIGH LEVELS THOUGH, SO SOME CIRRUS AGAIN LOOKS PROBABLE. HIGHS IN THE 50S CONTINUE TO SEEM REASONABLE, SO ONLY MADE MINOR TWEAKS. WINDS SHOULD STAY UP SOME MONDAY NIGHT, KEEPING TEMPS FAIRLY MIXED AND A BIT WARMER THAN TONIGHT. WARMING SHOULD CONTINUE INTO TUESDAY WITH 850MB TEMPS RETURNING INTO THE LOWER TO MID TEENS C. CONTINUED WITH HIGHS IN THE UPPER 50S TO LOW 60S. THE NEXT UPPER TROUGH WILL MOVE OUT INTO THE NORTHERN PLAINS BY TUESDAY, WITH ANOTHER PACIFIC FRONTAL BOUNDARY MOVING INTO THE WESTERN PLAINS BY LATE IN THE DAY. THE LACK OF LOW LEVEL MOISTURE WILL AGAIN BE A FACTOR, SO CONTINUED TO KEEP VERY LOW POPS OF 10- 15 FOR TUESDAY AFTERNOON FOR NOW. DAYS 3-7... FORECAST CHALLENGE THIS PERIOD IS THE EXPECTED SENSIBLE WEATHER FROM A DEEPENING MID-WEEK SYSTEM. BASED ON EXPECTED FORCING FROM THE TROPICS AND RESULTING AMPLIFICATION DOWNSTREAM...THE SYSTEM THAT CURRENTLY IS IN THE NORTHEAST PACIFIC SHOULD DIG INTO THE CENTRAL PLAINS LATE TUESDAY/WEDNESDAY. HOWEVER, EVERYTHING WILL LIKELY BE TOO FAR EAST OF MY CWA TO OFFER MUCH HOPE FOR PCPN. WIND AND BRIEFLY COLDER TEMPS WILL BE IN THE OFFING THOUGH. THEN A QUICK WARMUP IS EXPECTED LATE IN THE WEEK AS HEIGHTS BEGIN TO RISE AGAIN IN RESPONSE TO A FULL LATITUDE TROUGH THAT IS EXPECTED ALONG THE WEST COAST. && .PRELIMINARY POINT TEMPS/POPS... DDC 27 55 36 60 / 20 0 0 10 GCK 26 54 33 61 / 20 0 0 10 EHA 26 57 35 65 / 20 0 0 10 LBL 25 57 33 65 / 20 0 0 10 HYS 28 55 37 57 / 30 0 0 10 P28 33 58 40 62 / 20 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ FN26/07 ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TOPEKA KS 254 PM CST SUN NOV 12 2006 .DISCUSSION... LATEST SURFACE ANALYSIS HAD FRONTAL BOUNDARY FROM NORTHEAST NEBRASKA SOUTHWEST INTO SOUTHWEST KANSAS TO SURFACE LOW NEAR KDHT. RADARS PICKING UP ON SOME MID LEVEL CLOUDS DEVELOPING ACROSS CENTRAL KANSAS THIS AFTERNOON. WATER VAPOR LOOP HAS BASE OF THE UPPER TROUGH OVER NEW MEXICO WITH A SHORTWAVE MOVING THROUGH THE BASE OF THE TROUGH. MID AND HIGH LEVEL MOISTURE SHOWING UP ON MOISTURE CHANNEL FROM THE BAJA OF CALIFORNIA INTO NORTHWEST MISSOURI. MODELS ARE DIFFERING ON QPF FOR TONIGHT WITH THE RUC KEEPING MOST OF THE CWA DRY BUT FOCUSING ON NORTHERN BORDER THROUGH 06Z. GFS BROADER WITH PRECIPITATION WITH HIGHEST AMOUNTS NORTH OF INTERSTATE 70. MORNING SOUNDINGS WERE VERY DRY AND FORECAST SOUNDINGS SHOW THAT IT WILL TAKE A FEW HOURS TO SATURATE THE AIRMASS FOR PRECIPITATION. LIFT WILL LAST A LITTLE LONGER OVER EASTERN KANSAS WITH UPPER TROUGH MOVING THROUGH AXIS MOVING THROUGH AROUND 09Z. HAVE EXTENDED PRECIPITATION CHANCES IN THE EASTERN COUNTIES THROUGH 09Z. CLOUDS WILL LINGER A LITTLE LONGER TONIGHT AND HAVE ADJUSTED LOWS UPWARD ACROSS THE SOUTHEAST TWO THIRDS OF THE CWA. FOR MONDAY...MOSTLY SUNNY SKIES WILL PREVAIL INTO THE EARLY AFTERNOON WITH SOME HIGH CLOUDS INCREASING IN THE AFTERNOON HOURS. ADJUSTED HIGHS SLIGHTLY FROM PREVIOUS FORECAST WITH MID 50S. MONDAY NIGHT THROUGH WEDNESDAY...MODELS STILL SHOW CONSIDERABLE DISAGREEMENT ON EVOLUTION OF H5 PATTERN AND THE AFFECTS ON THE SURFACE FEATURES. GFS IS STILL MUCH SLOWER AND DEEPER WITH DEVELOPMENT OF H5 TROUGH. WHILE OTHER MODELS HAVE TRENDED STRONGER...A WEAKER VERSION OF THE GFS IS STILL PREFERRED. AS UPPER FEATURE DIGS IN...SURFACE BOUNDARY/LOW WILL MOVE EAST ACROSS THE CENTRAL PLAINS...ACROSS THE TOP CWA TUESDAY NIGHT. NOT MUCH CHANGE MADE TO THE GOING FORECAST AS BEST CHANCES FOR PRECIP WILL BE ACROSS THE NORTHEAST CWA...IN CLOSER VICINITY TO DEEPENING SURFACE LOW. A QUICK CHANGE OVER TO SNOW LATE WEDS NIGHT/EARLY THU MORNING CANNOT BE RULED OUT...BUT STILL KEPT LIQUID PRECIP AS STILL PLENTY OF DOUBT ON COLD AIR TIMING AND MAGNITUDE. PRECIP WILL COME TO AN END BY EARLY WEDS MORNING. AS FAR AS TEMPERATURES GO...HIGHS ON TUESDAY WILL BE IN THE UPPER 50S AND LOW 60S WITH GOOD WAA. OFFSETTING THE WAA SOMEWHAT WILL BE SIGNIFICANT MID CLOUD COVER. BY COMPARISON...STRONG CAA BEHIND SURFACE LOW WILL KEEP HIGHS ON WEDS IN THE LOW TO MID 40S. THURSDAY THROUGH SUNDAY...DEEP H5 LOW LIFTS FROM THE OHIO VALLEY THROUGH THE GREAT LAKES AND INTO CANADA. FLOW ALOFT WILL INITIALLY RETURN TO ZONAL BEFORE RIDGING STARTS TO TAKE PLACE OVER THE WEEKEND ACROSS THE WESTERN HALF OF THE U.S. EXTENDED FORECAST CONTINUES TO LOOK DRY BUT TEMPERATURES LOOK SLOW TO REBOUND AS FLOW ALOFT WILL STAY FROM THE NORTHWEST THROUGH MUCH OF THE PERIOD...SO EXPECT TEMPERATURES TO BE NEAR SEASONAL AVERAGES. .TOP WATCHES/WARNINGS/ADVISORIES...NONE. && $$ ks AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1249 PM EST SUN NOV 12 2006 .AVIATION... MVFR CLOUDS TO HOLD ON A LITTLE LONGER TODAY BEFORE FINALLY SCATTERING OUT. THIN LAYER OF MOISTURE TRAPPED BENEATH SUBSIDENCE INVERSION REFUSES TO RELENT...BUT STRONG SUBSIDENCE INVERSION WILL CONTINUE TO LOWER AS LOW LEVEL WARM AIR ADVECTION PERSISTS INTO THE EVENING HOURS. THEN VFR EXPECTED TONIGHT AS CLOUDS FINALLY SCOUR OUT. CIRROSTRATUS WILL THEN MOVE IN MONDAY MORNING AHEAD OF THE NEXT SHORTWAVE. && .PREV DISCUSSION...ISSUED 1145 AM EST SUN NOV 12 2006 UPDATE... STRATOCUMULUS CLOUDS CONTINUE TO PERSIST DESPITE RIDGE AXIS OVERHEAD. SOUNDINGS REVEAL THAT THE MOISTURE TRAPPED AT 925MB IS VERY SHALLOW...AND LATEST MODEL DATA INSISTS RAPID EROSION OF THIS MOISTURE THIS AFTERNOON. BUT GIVEN LATEST SATELLITE IMAGES AND SURFACE OBSERVATIONS...WILL GO AHEAD AND SLOW DOWN THE CLEARING TREND BY A COUPLE OF HOURS. IT WILL LIKELY BE AFTER SUNSET BEFORE WE COMPLETELY SCOUR OUT THIS MOISTURE...BUT WE DO STILL EXPECT SKIES BECOMING PARTLY SUNNY DURING THE AFTERNOON...AS THE RIDGE AXIS PASSES TO THE EAST. ALSO LOWERED TEMPS ABOUT 3 DEGREES. BUT DO HOWEVER STILL EXPECT ENOUGH SUNSHINE AND WARM AIR ADVECTION TO ALLOW MIXING UP TO 925MB...WHICH WOULD LEAD TO TEMPERATURES IN THE LOW 40'S. PREV DISCUSSION...ISSUED 700 AM EST SUN NOV 12 2006 AVIATION... THE WEAK BUT PERSISTENT BANDING OF SPRINKLES/FLURRIES DETECTED COMING OFF OF SAGINAW BAY AND ALSO CLIPPING AREAS PRIMARILY NEAR THE SOUTHERN TIP OF LAKE HURON OVERNIGHT HAS OVERALL WEAKENED BUT IS STILL DISCERNIBLE IN AVAILABLE RADAR IMAGERY. HARDER TO EXPLAIN IS THE DEGREE OF CLEARING LATE IN THE OVERNIGHT OVER PARTS OF SOUTHEAST MI. BELIEVE THAT THE THINNING/CLEARING IS RELATED AT LEAST IN PART TO RELATIVE SUBSIDENCE BETWEEN THE CONVERGENCE PLUMES ASSOCIATED WITH THE LAKE EFFECT BANDS. THIS MAY ALSO EXPLAIN WHY SOME AREAS ARE TENDING TO FILL BACK IN AGAIN WITH CLOUDS AS THE LAKE EFFECT/CONVERGENCE WEAKENS. THIS WEAKENING TREND IS STILL SUPPORTED BY THE 06Z GFS/NAM AND LATEST RUC. SO...FOR THE TAFS...THE ONLY ISSUE IS IN GETTING RID OF THE LOW CLOUDS. MOST MODEL SOUNDINGS DO LOOK TO WIDEN THE LOW LEVEL TEMPERATURE/DEW POINT SPREAD ENOUGH TO SUGGEST LOSS OF THE OCCASIONAL MAINLY MVFR CEILINGS BY MID DAY...SO HAVE WRITTEN THE TAFS ACCORDINGLY. OTHERWISE...NO CEILINGS...DRY AND VFR AS RIDGE AT THE SURFACE AND ALOFT MOVES OVER THE AREA. UPDATE... RECENTLY UPDATED TO REMOVE EARLY MORNING WORDING FROM ZONES AND TO TWEAK FORECAST TODAY MAINLY FOR SKY CONDITIONS THIS MORNING. UNEXPECTED DEGREE AND PERSISTENCE OF THINNING/CLEARING OVER MUCH OF THE EASTERN AND SOUTHERN COUNTIES OF SOUTHEAST MICHIGAN. PREV DISCUSSION...ISSUED 358 AM EST SUN NOV 12 2006 SHORT TERM...TODAY AND TONIGHT MODELS IN PRETTY GOOD AGREEMENT AS FOR THE SYNOPTIC PICTURE. SURFACE RIDGE TO PASS SLOWLY EAST ACROSS SOUTHEAST MI TODAY INTO TONIGHT. AT 500 MB...MEANWHILE...SHORTWAVE RIDGE OVERHEAD TODAY TO RETREAT EAST TONIGHT. EXCEPT AS NOTED BELOW...OVERALL DESCENT SEEN IN OMEGA FIELDS TODAY INTO TONIGHT...WITH QVECTOR CONVERGENCE ALSO INDICATING MOSTLY DIVERGENCE/SUBSIDENCE. 850 TO 500 MB MOISTURE RATHER MEAGER THROUGH TONIGHT. INCREASING CIRRUS...THOUGH...LIKELY TO BE SEEN MAINLY LATE TONIGHT BEHIND RIDGE ALOFT. LOW LEVEL MOISTURE...AS AT 925 MB...EXPECTED TO DIMINISH TODAY. THE EXCEPTION TO NO WEATHER IS THE OVERNIGHT SPRINKLES AND FLURRIES SEEN OVER MUCH OF THE FORECAST AREA...LARGELY RELATED TO LAKE EFFECT FROM NORTH TO NORTHEAST FLOW OFF OF LAKE HURON. DELTA TS INTO THE LOWER TEENS EARLIER IN THE NIGHT SHOULD LESSEN STEADILY THIS MORNING AS 850 MB TEMPERATURES WARM BEHIND THE BRIEF THERMAL TROUGH. NAM/RUC AND GFS SHOW GOOD LOW LEVEL CONVERGENCE...TENDING TO MAXIMIZE AROUND 06Z...ALSO ON THE WANE THIS MORNING. NAM ALSO SHOWS MODEST 950 MB OMEGA LIFT...MAINLY IN THE THUMB...WANING THIS MORNING. WILL CARRY MENTION OF SPRINKLES OR FLURRIES INTO THE MORNING FOR MOST OF THE AREA...THEN RIDGE OVERHEAD THIS AFTERNOON SHOULD KILL OFF ANY MORE POSSIBILITY OF THIS TRACE PRECIPITATION. PERSISTENCE OF SPRINKLES...AS OPPOSED TO FLURRIES...SEEMS RELATED TO SHALLOW DEPTH OF MOISTURE AND THUS VERY POOR ICE NUCLEATION POTENTIAL...AS PER MODEL SOUNDINGS. AS FOR CLOUD COVER TODAY...MOST MODELS INDICATE LESSENING BY AFTERNOON...AND WILL SO INDICATE. SATELLITE IMAGERY ALREADY SHOWING SOME THIN SPOTS/HOLES IN THE CLOUD COVER. DAYTIME MIXING SHOULD AID IN CLOUD COVER DECREASE. LONG TERM...MONDAY THROUGH SUNDAY CONFIDENCE IS INCREASING FOR A POTENT STORM TO IMPACT THE REGION FOR MID WEEK...HOWEVER...PREDICTABILITY OF THE EVENTUAL UPPER FLOW REGIME ACROSS THE CONUS REMAINS BELOW AVERAGE. SATELLITE DERIVED WINDS IN THE EASTERN PACIFIC AS OF 03Z WERE AVERAGING AROUND 120KTS WITH A DEVELOPING JET STREAK APPROACHING 150KTS EAST OF 150W IN BETWEEN 40-50N. GLOBAL MODELS SEEM TO HAVE INITIALIZED THE PACIFIC JET ORIENTATION AND GENERAL STRENGTH AS THE ECMWF APPEARS TO HAVE PICKED UP THE JET STREAK EARLIER THAN THE OTHER OPERATIONAL GLOBAL MODELS. THIS FEATURE(S) WILL BE OUR FORECAST CHALLENGE FOR THIS UPCOMING WEEK. BEGINNING WITH MONDAY...LONG WAVE TROUGH CURRENTLY PROGRESSING THROUGH THE INTERMOUNTAIN WEST AND EMBEDDED SHORT WAVE ACROSS THE FOUR CORNERS WILL LIFT NORTHEAST THROUGH THE DAY AS SHORT WAVE RIDGE AND SURFACE HIGH PRECEDING IT SLIDES FURTHER EAST. WHILE A GOOD AERIAL COVERAGE OF PRECIP IS EXPECTED TO ACCOMPANY THIS FEATURE INITIALLY...DECREASING THERMAL GRADIENT IN THE LOW-MID LEVELS ACROSS THE MID-UPPER MISSISSIPPI RIVER VALLEY AND BEST UPPER SUPPORT WILL LIFT INTO CANADA AND REDUCE THE CHANCES OF PRECIP FOR THE CWA. IN FACT...HARD TO FIND A MODEL THAT PRINTS ANY QPF ACROSS THE CWA. DO NOT FEEL COMPELLED TO REMOVE POPS COMPLETELY AND WILL RETAIN THE CURRENT FORECAST WITH 20% POPS ALONG AND NORTH OF 8-MILE WITH 30% POPS AROUND THE TRI CITIES. THEN A BRIEF RESPITE MONDAY NIGHT INTO TUESDAY AS WEAK SURFACE HIGH AND SHORT WAVE RIDGE AXIS MOVES ACROSS THE GREAT LAKES. HOWEVER... LOW LEVEL MOISTURE REMAINS RATHER HIGH AS OBSERVED IN THE GFS/NAM/WRF-HEMI SOUNDINGS HENCE THE PERCENT CLOUD COVER WILL REMAIN RATHER HIGH THROUGH EARLY TUESDAY MORNING. POTENT PACIFIC JET COMES ASHORE AND DIVES SOUTHEAST INTO THE THE FOUR CORNERS REGION TUESDAY NIGHT WITH SURFACE LOW DEVELOPING IN THE VICINITY OF THE PANHANDLE OF TEXAS. DEPENDING ON HOW THIS PATTERN UNFOLDS ACROSS THE CONUS...TRENDS IN THE GLOBAL MODELS SUGGEST UPPER PATTERN QUICKLY BECOMES NEGATIVELY TILTED AS GULF OF MEXICO MOISTURE ADVANCES NORTHWARD WEDNESDAY-WEDNESDAY NIGHT. CROSS SECTIONS FROM THE GFS SHOW A RATHER POTENT PETTERSSEN 2-D FGEN LAYER BETWEEN 850-700MB WITH AN INCREASED SLANTWISE INSTABILITY (INCLUDING DEPTH) JUST ABOVE THIS LAYER AS SUGGESTED IN THE LOWERING EPV/S ACROSS THE CWA. COULD SEE A BAND(S) OF HEAVY RAIN AND THUNDER WEDNESDAY AFTERNOON INTO THURSDAY MORNING...THIS WILL NEED TO MONITORED CLOSELY AS PWATS ARE EXPECTED TO CLIMB IN EXCESS OF 1 INCH. LOW BECOMES VERTICALLY STACKED ACROSS THE STATE THROUGH THURSDAY WITH A SLOW RETREAT NORTHWARD THROUGH THE END OF THIS WEEK. 850MB TEMPS DROP BACK TOWARD THE NEGATIVE TERRITORY AND PERHAPS EVEN LOWER INTO THE WEEKEND AS UPPER FLOW AMPLIFIES TOWARD A RIDGE ACROSS THE ROCKIES AND A TROUGH ACROSS THE GREAT LAKES/MIDDLE ATLANTIC COAST. THIS SETS THE STAGE FOR THE CHANCE OF SNOW SHOWERS FROM THE COLD/MOIST CYCLONIC FLOW AND CONTRIBUTIONS FROM LAKE MICHIGAN. WILL GO LOWER THAN MEX NUMBERS AND ADD POPS FOR SNOW THROUGH AT LEAST NEXT SATURDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421...NEARSHORE WATERS FROM PORT AUSTIN T SUNDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ AVIATION/UPDATE...JDS SHORT TERM...DWD LONG TERM....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 1145 AM EST SUN NOV 12 2006 .UPDATE... STRATOCUMULUS CLOUDS CONTINUE TO PERSIST DESPITE RIDGE AXIS OVERHEAD. SOUNDINGS REVEAL THAT THE MOISTURE TRAPPED AT 925MB IS VERY SHALLOW...AND LATEST MODEL DATA INSISTS RAPID EROSION OF THIS MOISTURE THIS AFTERNOON. BUT GIVEN LATEST SATELLITE IMAGES AND SURFACE OBSERVATIONS...WILL GO AHEAD AND SLOW DOWN THE CLEARING TREND BY A COUPLE OF HOURS. IT WILL LIKELY BE AFTER SUNSET BEFORE WE COMPLETELY SCOUR OUT THIS MOISTURE...BUT WE DO STILL EXPECT SKIES BECOMING PARTLY SUNNY DURING THE AFTERNOON...AS THE RIDGE AXIS PASSES TO THE EAST. ALSO LOWERED TEMPS ABOUT 3 DEGREES. BUT DO HOWEVER STILL EXPECT ENOUGH SUNSHINE AND WARM AIR ADVECTION TO ALLOW MIXING UP TO 925MB...WHICH WOULD LEAD TO TEMPERATURES IN THE LOW 40'S. && .PREV DISCUSSION...ISSUED 700 AM EST SUN NOV 12 2006 AVIATION... THE WEAK BUT PERSISTENT BANDING OF SPRINKLES/FLURRIES DETECTED COMING OFF OF SAGINAW BAY AND ALSO CLIPPING AREAS PRIMARILY NEAR THE SOUTHERN TIP OF LAKE HURON OVERNIGHT HAS OVERALL WEAKENED BUT IS STILL DISCERNIBLE IN AVAILABLE RADAR IMAGERY. HARDER TO EXPLAIN IS THE DEGREE OF CLEARING LATE IN THE OVERNIGHT OVER PARTS OF SOUTHEAST MI. BELIEVE THAT THE THINNING/CLEARING IS RELATED AT LEAST IN PART TO RELATIVE SUBSIDENCE BETWEEN THE CONVERGENCE PLUMES ASSOCIATED WITH THE LAKE EFFECT BANDS. THIS MAY ALSO EXPLAIN WHY SOME AREAS ARE TENDING TO FILL BACK IN AGAIN WITH CLOUDS AS THE LAKE EFFECT/CONVERGENCE WEAKENS. THIS WEAKENING TREND IS STILL SUPPORTED BY THE 06Z GFS/NAM AND LATEST RUC. SO...FOR THE TAFS...THE ONLY ISSUE IS IN GETTING RID OF THE LOW CLOUDS. MOST MODEL SOUNDINGS DO LOOK TO WIDEN THE LOW LEVEL TEMPERATURE/DEW POINT SPREAD ENOUGH TO SUGGEST LOSS OF THE OCCASIONAL MAINLY MVFR CEILINGS BY MID DAY...SO HAVE WRITTEN THE TAFS ACCORDINGLY. OTHERWISE...NO CEILINGS...DRY AND VFR AS RIDGE AT THE SURFACE AND ALOFT MOVES OVER THE AREA. UPDATE... RECENTLY UPDATED TO REMOVE EARLY MORNING WORDING FROM ZONES AND TO TWEAK FORECAST TODAY MAINLY FOR SKY CONDITIONS THIS MORNING. UNEXPECTED DEGREE AND PERSISTENCE OF THINNING/CLEARING OVER MUCH OF THE EASTERN AND SOUTHERN COUNTIES OF SOUTHEAST MICHIGAN. PREV DISCUSSION...ISSUED 358 AM EST SUN NOV 12 2006 SHORT TERM...TODAY AND TONIGHT MODELS IN PRETTY GOOD AGREEMENT AS FOR THE SYNOPTIC PICTURE. SURFACE RIDGE TO PASS SLOWLY EAST ACROSS SOUTHEAST MI TODAY INTO TONIGHT. AT 500 MB...MEANWHILE...SHORTWAVE RIDGE OVERHEAD TODAY TO RETREAT EAST TONIGHT. EXCEPT AS NOTED BELOW...OVERALL DESCENT SEEN IN OMEGA FIELDS TODAY INTO TONIGHT...WITH QVECTOR CONVERGENCE ALSO INDICATING MOSTLY DIVERGENCE/SUBSIDENCE. 850 TO 500 MB MOISTURE RATHER MEAGER THROUGH TONIGHT. INCREASING CIRRUS...THOUGH...LIKELY TO BE SEEN MAINLY LATE TONIGHT BEHIND RIDGE ALOFT. LOW LEVEL MOISTURE...AS AT 925 MB...EXPECTED TO DIMINISH TODAY. THE EXCEPTION TO NO WEATHER IS THE OVERNIGHT SPRINKLES AND FLURRIES SEEN OVER MUCH OF THE FORECAST AREA...LARGELY RELATED TO LAKE EFFECT FROM NORTH TO NORTHEAST FLOW OFF OF LAKE HURON. DELTA TS INTO THE LOWER TEENS EARLIER IN THE NIGHT SHOULD LESSEN STEADILY THIS MORNING AS 850 MB TEMPERATURES WARM BEHIND THE BRIEF THERMAL TROUGH. NAM/RUC AND GFS SHOW GOOD LOW LEVEL CONVERGENCE...TENDING TO MAXIMIZE AROUND 06Z...ALSO ON THE WANE THIS MORNING. NAM ALSO SHOWS MODEST 950 MB OMEGA LIFT...MAINLY IN THE THUMB...WANING THIS MORNING. WILL CARRY MENTION OF SPRINKLES OR FLURRIES INTO THE MORNING FOR MOST OF THE AREA...THEN RIDGE OVERHEAD THIS AFTERNOON SHOULD KILL OFF ANY MORE POSSIBILITY OF THIS TRACE PRECIPITATION. PERSISTENCE OF SPRINKLES...AS OPPOSED TO FLURRIES...SEEMS RELATED TO SHALLOW DEPTH OF MOISTURE AND THUS VERY POOR ICE NUCLEATION POTENTIAL...AS PER MODEL SOUNDINGS. AS FOR CLOUD COVER TODAY...MOST MODELS INDICATE LESSENING BY AFTERNOON...AND WILL SO INDICATE. SATELLITE IMAGERY ALREADY SHOWING SOME THIN SPOTS/HOLES IN THE CLOUD COVER. DAYTIME MIXING SHOULD AID IN CLOUD COVER DECREASE. LONG TERM...MONDAY THROUGH SUNDAY CONFIDENCE IS INCREASING FOR A POTENT STORM TO IMPACT THE REGION FOR MID WEEK...HOWEVER...PREDICTABILITY OF THE EVENTUAL UPPER FLOW REGIME ACROSS THE CONUS REMAINS BELOW AVERAGE. SATELLITE DERIVED WINDS IN THE EASTERN PACIFIC AS OF 03Z WERE AVERAGING AROUND 120KTS WITH A DEVELOPING JET STREAK APPROACHING 150KTS EAST OF 150W IN BETWEEN 40-50N. GLOBAL MODELS SEEM TO HAVE INITIALIZED THE PACIFIC JET ORIENTATION AND GENERAL STRENGTH AS THE ECMWF APPEARS TO HAVE PICKED UP THE JET STREAK EARLIER THAN THE OTHER OPERATIONAL GLOBAL MODELS. THIS FEATURE(S) WILL BE OUR FORECAST CHALLENGE FOR THIS UPCOMING WEEK. BEGINNING WITH MONDAY...LONG WAVE TROUGH CURRENTLY PROGRESSING THROUGH THE INTERMOUNTAIN WEST AND EMBEDDED SHORT WAVE ACROSS THE FOUR CORNERS WILL LIFT NORTHEAST THROUGH THE DAY AS SHORT WAVE RIDGE AND SURFACE HIGH PRECEDING IT SLIDES FURTHER EAST. WHILE A GOOD AERIAL COVERAGE OF PRECIP IS EXPECTED TO ACCOMPANY THIS FEATURE INITIALLY...DECREASING THERMAL GRADIENT IN THE LOW-MID LEVELS ACROSS THE MID-UPPER MISSISSIPPI RIVER VALLEY AND BEST UPPER SUPPORT WILL LIFT INTO CANADA AND REDUCE THE CHANCES OF PRECIP FOR THE CWA. IN FACT...HARD TO FIND A MODEL THAT PRINTS ANY QPF ACROSS THE CWA. DO NOT FEEL COMPELLED TO REMOVE POPS COMPLETELY AND WILL RETAIN THE CURRENT FORECAST WITH 20% POPS ALONG AND NORTH OF 8-MILE WITH 30% POPS AROUND THE TRI CITIES. THEN A BRIEF RESPITE MONDAY NIGHT INTO TUESDAY AS WEAK SURFACE HIGH AND SHORT WAVE RIDGE AXIS MOVES ACROSS THE GREAT LAKES. HOWEVER... LOW LEVEL MOISTURE REMAINS RATHER HIGH AS OBSERVED IN THE GFS/NAM/WRF-HEMI SOUNDINGS HENCE THE PERCENT CLOUD COVER WILL REMAIN RATHER HIGH THROUGH EARLY TUESDAY MORNING. POTENT PACIFIC JET COMES ASHORE AND DIVES SOUTHEAST INTO THE THE FOUR CORNERS REGION TUESDAY NIGHT WITH SURFACE LOW DEVELOPING IN THE VICINITY OF THE PANHANDLE OF TEXAS. DEPENDING ON HOW THIS PATTERN UNFOLDS ACROSS THE CONUS...TRENDS IN THE GLOBAL MODELS SUGGEST UPPER PATTERN QUICKLY BECOMES NEGATIVELY TILTED AS GULF OF MEXICO MOISTURE ADVANCES NORTHWARD WEDNESDAY-WEDNESDAY NIGHT. CROSS SECTIONS FROM THE GFS SHOW A RATHER POTENT PETTERSSEN 2-D FGEN LAYER BETWEEN 850-700MB WITH AN INCREASED SLANTWISE INSTABILITY (INCLUDING DEPTH) JUST ABOVE THIS LAYER AS SUGGESTED IN THE LOWERING EPV/S ACROSS THE CWA. COULD SEE A BAND(S) OF HEAVY RAIN AND THUNDER WEDNESDAY AFTERNOON INTO THURSDAY MORNING...THIS WILL NEED TO MONITORED CLOSELY AS PWATS ARE EXPECTED TO CLIMB IN EXCESS OF 1 INCH. LOW BECOMES VERTICALLY STACKED ACROSS THE STATE THROUGH THURSDAY WITH A SLOW RETREAT NORTHWARD THROUGH THE END OF THIS WEEK. 850MB TEMPS DROP BACK TOWARD THE NEGATIVE TERRITORY AND PERHAPS EVEN LOWER INTO THE WEEKEND AS UPPER FLOW AMPLIFIES TOWARD A RIDGE ACROSS THE ROCKIES AND A TROUGH ACROSS THE GREAT LAKES/MIDDLE ATLANTIC COAST. THIS SETS THE STAGE FOR THE CHANCE OF SNOW SHOWERS FROM THE COLD/MOIST CYCLONIC FLOW AND CONTRIBUTIONS FROM LAKE MICHIGAN. WILL GO LOWER THAN MEX NUMBERS AND ADD POPS FOR SNOW THROUGH AT LEAST NEXT SATURDAY. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LAKE HURON...SMALL CRAFT ADVISORY...LHZ421...NEARSHORE WATERS FROM PORT AUSTIN T SUNDAY. LAKE ST CLAIR...NONE. MI WATERS OF LAKE ERIE...NONE. && $$ UPDATE...JDS SHORT TERM...DWD LONG TERM....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 NEWPORT/MOREHEAD CITY NC 1210 PM EST SUN NOV 12 2006 .SHORT TERM /REST OF TODAY/...SURFACE LOW PRES AND ASSOCIATED COLD FRONT ARE LIFTING NEWD OFF THE NRN OBX LATE THIS MORNING WITH THE UPPER LOW ACROSS CENTRAL NC. A WIDE AREA OF WRAP AROUND RAINFALL IS CONTINUING ACROSS MUCH OF THE WESTERN PORTION OF THE CWA. TEMPERATURES HAVE FALLEN INTO THE 50S BEHIND THE FRONT AND WINDS HAVE INCREASED UP TO 15 MPH WITH GUSTS 25-30 MPH AS STRONG CAA HAS COMMENCED. THE LOW PRES WILL SLOWLY LIFT NEWD THIS AFTERNOON WITH THE WRAP AROUND RAINFALL SLOWLY ENDING ACROSS THE SERN PORTION OF THE CWA THIS AFTERNOON. LOW PRES WILL BE SLOW TO PUSH EAST OF THE VA CAPES TODAY AND TONIGHT AS THE UPPER LOW BECOME CUTOFF ALLOWING FOR WRAP AROUND RAINFALL TO CONTINUE ACROSS NERN NC THIS AFTERNOON AND EVENING...WITH COVERAGE DIMINISHING THIS EVENING. UPDATED THE ZONES AND GRIDS TO CAPTURE CURRENT PCPN AND TEMPERATURE TRENDS. && .AVIATION...WIDESPREAD MVFR CONDITIONS WITH AREAS OF IFR WILL PREVAIL THIS AFTN INTO THIS EVENING...GRADUALLY IMPROVING LATE TONIGHT AND MON. && .MARINE...SIGNIFICANT UPDATE THIS MORNING AS SFC LOW TRACKED FARTHER S THAN FCST AND SW WINDS NEVER REACHED GALE FORCE. RUC HAD BEST HANDLE ON SFC LOW AND WINDS 12-15Z AND LEANED TO IT FOR UPDATE THROUGH EARLY THIS EVENING. NOW EXPECT GALES (MAINLY IN GUSTS) TO SPREAD OVER WATERS FROM S TO N THIS AFTN AS SFC LOW GRADUALLY MOVES NE AND CAA KICKS IN BEHIND IT. EXTENDED GALES TO ALL WATERS (EXCEPT SCA FOR SOUNDS) AND IN TIME TO 06Z TONIGHT. ADJUSTED SEAS FOR CURRENT BUOY OBS OF 6-9 FT...WW3 IS UNDERDONE. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 4 AM EST MONDAY FOR AMZ130-135. GALE WARNING UNTIL 1 AM EST MONDAY FOR AMZ152-154-156-158. GALE WARNING UNTIL 1 AM EST MONDAY FOR AMZ150. && $$ SHORT TERM...KENNEDY AVIATION...MERRELL MARINE...MERRELL nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 100 PM CST SUN NOV 12 2006 .UPDATE... TEMPERATURES WARMER THAN EXPECTED IN CLEAR SKY AREAS... AND COOLER IN CLOUDY REGIONS. SUNNY SKIES IN SOUTHEAST NORTH DAKOTA AND NORTHWESTERN MINNESOTA WITH CLOUDY SKIES SURROUNDING. CURRENTLY SURFACE BOUNDARY IS ALONG HALLOCK-GRAND FORKS-OAKES LINE AND MOVING EAST. SKY COVER IS EXPECTED TO INCREASE FOLLOWING THIS LINE. WINDS WILL ALSO SHIFT FROM SOUTH TO NORTHWEST FOLLOWING THE BOUNDARY. CHALLENGES WERE THE TIMING OF THE CLOUD COVER CHANGES AND CORRESPONDING TEMPERATURES. RUC IS HANDLING CURRENT CONDITIONS THE BEST... PARTICULARLY THE SKY COVER AND SURFACE TEMPERATURES. MOS GUIDANCE AND NAM SURFACE TEMPERATURES WERE NOT HOLDING TRUE FOR CURRENT OBSERVATIONS. CLOUD COVER FOR FIRST PART OF FORECAST IS MORE CERTAIN THAN FOR LATER HOURS. GFS AND HPC BOTH SHOW SOME PRECIPITATION POSSIBLE IN THE SOUTHEAST FORECAST AREA BUT CLEARING CONDITIONS DO NOT SUPPORT THIS. TOOK OUT AFTERNOON PRECIPITATION CHANCES ACCORDINGLY. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ STEINBRUCKNER/GODON nd AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BLACKSBURG VA 1235 PM EST SUN NOV 12 2006 .AVIATION... LOW PRESSURE TO THE SE COMBO WITH UPSLOPE FLOW WESTERN SLOPES WILL KEEP RANGE OF CONDITIONS FROM IFR/MVFR SE WVA SITES TO VFR/OCNL ELSWHERE INTO THIS EVENING. SPOTTY -RA MAY OCCUR AT LYH/DAN WITH SPORADIC -RA/-SN BLF BUT OVERALL EXPECTING ONLY BRIEF REDUCTIONS IN VSBY. HOWEVER GUSTY N/NW WINDS WILL PREVAIL INTO LATE THIS AFTERNOON WITH SOME GUSTS ABOVE 30 KTS POSSIBLE ACROSS THE EASTERN SITES. SYSTEM EXITS THE COAST OVERNIGHT ALLOWING SOME DRYING TO TAKE PLACE ESPCLY EAST WHILE EXPECTING LOWER CEILINGS TO FILL BACK IN SE WVA WHERE MVFR/IFR LIKELY FOR THE MOST PART. RESIDUAL CLOUDS SHOULD FINALLY BREAK ON MONDAY ALTHO LINGERING MVFR CEILINGS AT TIMES EARLY WITH WITH LOW LEVEL RH HANGING ACROSS THE EAST. && .PREV DISCUSSION... (ISSUED 950 AM EST SUN NOV 12 2006) SHORT TERM /REST OF TODAY/... LOW PRES ALONG THE FRONT CONTINUES TO DRIFT SLOWLY NE THRU EASTERN NC THIS MORNING WITH ONGOING NEGATIVE TILT PULLING LIGHT/MOD RAIN BACK ACROSS MUCH OF THE PIEDMONT ATTM. EXPECT AS THE SYSTEM WORKS NE THIS AFTERNOON WILL SEE DRY AIR SLOWLY CUTOFF -RA ON THE SW SIDE AS MID LEVEL AXIS OF CONVERGENCE PIVOTS MORE INTO THE NERN ZONES WHERE WILL KEEP CAT/LIKELY POPS GOING. ELSW ABRUPT DROPOFF IN RH LIKELY ALONG THE SOUTHERN BLUE RIDGE PER NW DOWNSLOPE/SUBSIDENCE BEFORE GETTING BACK INTO MORE UPSLOPISH MOISTURE WESTERN SLOPES. HOWEVER GIVEN FLOW ALOFT MORE NORTHERLY AND BEST MOISTURE OUT WITH COASTAL LOW APPEARS EVEN UPSLOPE MIX OF PRECIP LIKELY VERY LIGHT/SPOTTY THIS AFTERNOON. THIS SEEN IN MOST MODEL OUTPUT ESPCLY LATEST WRF/NMM AND RUC WHICH HAVE VERY LIMITED COVERAGE. THUS PLAN TO CUT POPS TO CHANCE WESTERN SLOPES AND GO WITH LITTLE OR NO PRECIP FROM THE NEW RIVER VALLEY SOUTH. WINDS HAVE BEEN BELOW ADVISORY LEVELS SO FAR WITH WAVE SLOW TO MOVE NE/DEEPEN AND RATHER WEAK 85H JET. EXPECT ONCE ITS GETS A BIT FARTHER EAST AND MIXING INCREASES WILL SEE RIDGES PICK UP ALTHO FORECAST PRES RISES NOT ALL THAT GREAT FOR THE AFTERNOON. OTRW SOME SMALL ADJUSTS TO TEMPS SINCE APPEARS ONLY SLIGHT RISES AT BEST MOST AREAS THRU THE AFTERNOON. PREV DISCUSSION... (ISSUED 647 AM EST SUN NOV 12 2006) AVIATION... BLF WILL START OUT WITH IFR CONDITIONS THIS MORNING DUE TO STRONG LOW LEVEL WINS PUSHING MOISTURE UP THE MOUNTAINS. CEILINGS WILL IMPROVE GRADULLY WITH CEILINGS AT BLF BECOMING MVFR BY THE END OF THE DAY. LOW PRESSURE DEVELOPING IN NORTH CAROLINA WILL KEEP VFR CLOUDS IN OVER LYH THROUGH THIS EVENING. CLOUDS AT ROA AND DAN WILL BECOME SCATTERED AS THE DRY SLOT ADVANCES INTO THE REGION. WINDS WILL BE GUSTY TODAY OUT OF THE NORTH TO NORTHWEST. AS THE SURFACE LOW DEEPENS THE WINDS WILL INCREASE...ESPECIALLY EAST OF THE MOUNTAINS. PREV DISCUSSION... (ISSUED 221 AM EST SUN NOV 12 2006) SHORT TERM /TODAY/... DECIDED TO KEEP WIND ADVISORY UP TODAY FOR NORTHWEST MOUNTAINS OF NC NORTHWARD THRU GRAYSON...CARROL AND FLOYD COUNTIES. COLD FRONT CONTINUES ITS MARCH EAST TO THE ATLANTIC THIS MORNING. CLOSED LOW DEVELOPS ACROSS EASTERN VA/NC AND LIFTS TOWARDS NEW ENGLAND TONIGHT. BAND OF SHOWERS AND EMBEDDED THUNDERSTORMS MOVING ACROSS EASTERN THIRD THIS MORNING. WRAP AROUND LOW MOISTURE WILL CLIP THE FAR EAST TODAY AND EXPECT UPSLOPE CLOUDS IN THE WEST. MOST OF PCPN WILL BE LIQUID BUT SOME LIGHT SNOW IS POSSIBLE IN THE HIGHEST ELEVATION. NOT AS IMPRESSED WITH LIMITED MOISTURE AND MORE NORTHERLY WIND COMPONENT. PLAYED TEMPERATURES CLOSE TO MAV GUID. LONG TERM /TONIGHT THROUGH SATURDAY/... CLOSED LOW MOVES OFF THE COAST THEN TOWARD NEW ENGLAND TONIGHT AND MONDAY. WINDS WILL REMAIN STRONG AROUND THE LOW THIS EVENING...THEN START TO DIMINISH AS THE LOW MOVES FURTHER OFFSHORE TONIGHT. SURFACE WINDS WILL BE MUCH LIGHTER BY MONDAY AFTERNOON WITH HIGH PRESSURE APPROACHING AREA. THE Q-VECTOR FORCING AND DEFORMATION AREA STAY JUST EAST OF THE COUNTY WARNING AREA TONIGHT. HOWEVER CLOUDS WILL HOLD IN ACROSS THE EASTERN COUNTY WARNING AREA THROUGH MONDAY AFTERNOON. WENT WARMER THAN MET GUIDANCE ON MONDAY WHICH KEEPS THE PIEDMONT CLOUDY ALL DAY AND COOLER THAN MAV GUIDANCE WHICH HAS MORE SUN IN THE MORNING. COLD AIR IS VERY SHALLOW AND WARM AIR ADVECTION MODERATES THE AIRMASS WITH 850 MB TEMPERATURES WELL AABOVE ZERO BY MONDAY MORNING. SINCE LOW LEVEL WINDS ARE FROM THE NORTH THE UPSLOPE COMPONENT IS NOT THAT GOOD AND WITH SUCH SHALLOW MOISTURE AND COLD AIR AND VERY LIGHT QPF AMOUNTS WILL KEEP JUST LIGHT ANOUMTS OF RAIN AND SNOW IN SOUTHEAST WEST VIRIGINA THROUGH EARLY MONDAY. THE NEXT DEEP TROF DIGGING INTO THE MISSISSIPPI VALLEY ON TUESDAY AND WEDNESDAY WILL BEGIN TO BACK THE LOW LEVELS WINDS. THE LOW LEVEL SOUTHWEST FLOW ON TUESDAY WILL RESULT IN ABOVE NORMAL HIGH TEMPERATURES. MID AND HIGH LEVEL RELATIVE HUMIDITY AND CLOUDS MOVE INTO THE AREA AHEAD OF THIS SYSTEM ON TUESDAY NIGHT. BY WEDNESDAY NIGHT A STRONG LOW LEVEL JET OUT OF THE SOUTHEAST WILL BRING ABUNDANT MOISTURE OFF THE ATLANTIC. THE GOOD DYNAMICS AND UPPER DIFFLUENCE WEDNESDAY NIGHT STILL SUPPORT RAIN SO NO CHANGE NEEDED TO THE FORECAST..EXCEPT WILL INCREASE WINDS SPEEDS A BIT. AVIATION... COLD FRONT WILL EXIT CWA EARLY THIS MORNING. IN WAKE OF FRONT... WINDS WILL BECOME INCREASINGLY GUSTY THIS MORNING WITH SECONDARY PUSH OF WIND ALOFT GIVEN COLD ADVECTION. UPSLOPE FLOW COMBINED WITH LOW LEVEL MOISTURE AND COLD AIR MAY CREATE LOW CLOUDS AND SOME SNOW SHOWERS IN THE NORTHWEST WESTERN AREAS. LOW CLOUD DECK (MVFR/IFR) IN THE WEST WILL BE SLOW TO IMPROVE TODAY...WHILE IN THE EAST DOWNSLOPE FLOW SHOULD ALLOW FOR SOME BREAKS BY LATE MORNING. MVFR/IFR SHOWERS ARE POSSIBLE IN THE FAR EAST TODAY WITH WRAPAROUND PRECIP BAND AS UPPER LOW CLOSES OFF NEARBY. GUSTY AFTERNOON WINDS ARE POSSIBLE ...WITH POTENTIAL FOR GUSTS IN EXCESS OF 40KTS ACRS THE HIGHER ELEVATIONS. WINDS WILL DIMINISH TONIGHT WITH VFR CONDITIONS PREVAILING. MOUNTAIN OBSCURATIONS ARE POSSIBLE TODAY. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...WIND ADVISORY FOR VAZ015>017 UNTIL 7 PM SUNDAY. NC...WIND ADVISORY FOR NCZ001-002-018 UNTIL 7 PM SUNDAY. WV...NONE. && $$ JH va AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI 328 PM CST SUN NOV 12 2006 .DISCUSSION...FCST FOCUS IS ON PCPN CHCS WITH APPCH TROF TNT INTO MONDAY AND THEN HANDLING OF SYS FOR MID WEEK. IN THE SHORT TERM...VISIBLE SATELLITE IMAGERY SHOWED APPROACHING MID/HI CLOUDS AHEAD OF 500 MB WAVE THAT RUC ANALYSIS PLACED IN THE WRN DAKOTAS AT 20Z. SERLY SFC WINDS AS RIDGE OF HI PRES SHIFTED EAST BROUGHT REMNANTS OF PERSISTENT LAKE EFFECT CLOUDS ONSHORE...KEEPING LOCATIONS NEAR LAKE MI IN AND OUT OF CLOUDS. WILL MONITOR LATEST TRENDS FOR ERLY EVENING CLOUD FCST. COMPETING FACTORS MAKE PCPN CHANCES FOR CWA LATE TONIGHT/MONDAY MORNING DIFFICULT TO PIN DOWN. BEST ISENTROPIC LIFT ON BOTH NAM AND GFS 290-300K SFCS CROSSES CWA BETWEEN 00Z AND 06Z WITH 30-35 KT LLJ...BUT MOISTURE LAGGING. COND PRESSURE DEFICITS OF 100-200 MB WITH BEST LIFT...THO GFS HAS AN ANOMALOUS SECONDARY BULLSEYE OF NET ADIABATIC ISENTROPIC OMEGA AT 12Z OVER S CNTRL WI ON LEADING EDGE OF LOWERING PRES DEFICIT GRADIENT. GOES SOUNDER IMAGERY CONFIRMS DRY AIR IN PLACE OVER RGN...19Z RUC PWATS OF 0.25 INCH OR LESS OVER SRN WI...WITH RETURN FLOW JUST NOW LIFTING NWD ALONG SFC TROF AHEAD OF DEVELOPING SFC LOW IN PANHANDLE REGION. 850 MB DEW POINT FCSTS INDICATE NARROW RIBBON OF HIER DEW POINTS ARE COINCIDENT WITH 850 MB TROF AXIS...BUT BEHIND BEST ISENTROPIC LIFT. CROSS SECTIONS SHOW STRONG MID LVL FRONTOGENETIC FORCING OVER CWA BETWEEN 12Z AND 18Z...BUT BETTER OMEGA ALOFT IS OFFSET BY DOWNWARD AGEOSTROPHIC FLOW BELOW 800MB...PROBABLY FROM CAA AT 850 MB AND BELOW THAT BEGINS AROUND 06Z MON...WITH WEAK 1000-850 MB FRONTOGENESIS TO OUR WEST AT 00Z MON DIMINISHING WITH TIME AFTER 06Z TO NEAR NOTHING BY 12Z. NARROW THETA E RIDGE TO PUSH ALONG/AHEAD OF TROF AS IT CROSSES CWA MONDAY MORNING. WILL TIE WHAT SHOULD BE LIGHT/SCT PCPN TO THIS AXIS...WHICH ALSO ALIGNS WELL WITH COLUMN SATURATION ON BUFKIT SNDGS. TOP DOWN AND BOURGOIUN PCPN TYPE METHODS INDICATE ALL RAIN FOR CWA. NEXT CONCERN IS MIDWEEK SYSTEM. SWD TREND NOTED BY PREV FCSTR CONTINUES WITH SUN 18Z NAM RUN TRACKING SFC LOW DVLPG OVR SRN MO AT 06Z WED...THEN MOVG ALONG OHIO RVR VLY TO FAR S CNTRL OHIO BY 06Z THUR. 12Z GFS JUST A TAD FARTHER NORTH WITH LOW TRACK IN SAME TIME PERIOD...THEN LIFTS IT NWD TO NR WRN LAKE ERIE AND RETROGRADES/REDEVELOPS NR SAGINAW BAY AS CLOSED 500 MB LOW DEEPENS. 12Z ECMWF ALSO TRENDING WITH OHIO RVR SOLUTION BY 12Z THUR WITH CLOSED 500 LOW FARTHER SOUTH THAN PREV RUNS. WILL HOLD ON TO CHC POPS FOR WED AS WELL AS RAIN OR SNOW FOR TYPE WITH BETTER CLARITY EXPECTED FOR TRACK/TIMING IN LATER RUNS. && .MKX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ REM wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 310 PM CST SUN NOV 12 2006 .SHORT TERM...THROUGH WEDNESDAY NIGHT PRIMARY FORECAST CONCERNS WERE WITH PRECIPITATION CHANCE/TYPE TONIGHT INTO EARLY MONDAY AND AGAIN TUESDAY INTO WEDNESDAY NIGHT. INFRARED AND VISIBLE SATELLITE IMAGERY INDICATED CONSIDERABLE MID AND HIGH LEVEL CLOUDS ADVANCING ACROSS THE UPPER MISSISSIPPI VALLEY. THIS WAS IN ADVANCE OF SURFACE COLD FRONT...WHICH EXTENDED ACROSS EASTERN DAKOTAS AND NEBRASKA INTO CENTRAL KANSAS. NARROW BAND OF PRECIPITATION NOTED ON REGIONAL RADAR FROM NORTHEAST TO WEST CENTRAL MN. LATEST RUC SUPPORTS THIS PRECIPITATION AS ASSOCIATED WITH 700-500MB FRONTOGENESIS. WATER VAPOR IMAGERY INDICATED MID LEVEL TROUGH EXTENDING NORTH-SOUTH ACROSS NATIONS MIDSECTION...WITH VIGOROUS WAVE IN THE TEXAS PANHANDLE AREA. 12Z 12NOV06 MODEL SOLUTIONS HAD EXCELLENT CLUSTERING WITH RESPECT TO UPPER LEVEL SURFACE FEATURES AFFECTING THE FORECAST AREA TONIGHT INTO EARLY MONDAY. THEREFORE...FORECAST CONFIDENCE WAS HIGH THAT WE WILL RECEIVE A LIGHT PRECIPITATION EVENT. IN FACT...80-100 PERCENT OF GFS ENSEMBLES SUPPORTED PRECIPITATION DURING THE OVERNIGHT HOURS. IN ADDITION...NCEP SREF ENSEMBLE SUPPORTED HIGHER PROBABILITY OF SNOW IN NORTHERN PART OF THE FORECAST AREA...WITH BETTER PROBABILITY OF RAIN ELSEWHERE. ANOTHER AND MORE VIGOROUS SYSTEM SHOULD IMPACT PARTS OF THE MIDWEST AT MIDWEEK. EVEN THOUGH MODEL DETAILS STILL DIFFER A BIT...THE CONSENSUS APPEARS TO BE INCREASING TOWARD A SOLUTION OF A CLOSED 500MB LOW DEVELOPING OVER THE MID MISSISSIPPI AND LOWER OHIO VALLEY BY WEDNESDAY. THIS SHOULD EFFECTIVELY KEEP THE HEAVIEST QPF SOUTH OF OUR FORECAST AREA....WHICH AGREED WITH NCEP SREF ENSEMBLE MEMBERS. THEREFORE...CONFIDENCE WAS INCREASING IN THIS AS A PROBABLE SOLUTION...WHICH CURRENT DATA BASE ALREADY SUPPORTS. TONIGHT INTO EARLY MONDAY...MODELS CONTINUED TO INDICATE A CONSISTENT SIGNAL WITH REGARD TO FRONTOGENETIC FORCING ASSOCIATED WITH UPPER LEVEL WAVE. NORTH-SOUTH CROSS SECTION INDICATED A NARROW BUT STRONG UPWARD VERTICAL MOTION SIGNAL SLIDES ACROSS THE FORECAST AREA. THIS SUGGESTS PRECIPITATION MAY FALL STEADILY FOR AWHILE...ALTHOUGH TRANSITORY NATURE OF THE FORCING SHOULD PRECLUDE HEAVY AMOUNTS PER MODEL QPF. BECAUSE OF CONSISTENTLY STRONG FORCING SIGNAL... CONFIDENCE WAS HIGH TO INCREASE PRECIPITATION PROBABILITIES INTO CATEGORICAL VALUES. ACCORDING TO NCEP SREF AND BUFKIT PRECIPITATION TYPE ALGORITHMS... PRECIPITATION PROBABILITIES FOR SNOW SHOULD BE BEST ACROSS NORTHERN MOST SECTIONS OF THE FORECAST AREA. THEREFORE...TAILORED SNOW AMOUNTS IN THE DATA BASE ACCORDINGLY...WITH AROUND 2 INCHES OF ACCUMULATION IN NORTH CENTRAL WI AND AN INCH OR LESS ELSEWHERE. TUESDAY INTO WEDNESDAY NIGHT...MORE VIGOROUS SYSTEM SHOULD IMPACT PARTS OF THE MIDWEST...ALTHOUGH BEST DYNAMICS APPEAR TO RESIDE SOUTH OF THE FORECAST AREA WHERE 500MB LOW CLOSES OFF. DIFFERENCES IN STRENGTH OF FORCING NOTED BETWEEN NAM/WRF AND GFS...WITH GFS STRONGER WITH REGARD TO DEEP LAYERED Q-G CONVERGENCE. IN ADDITION... SREF AND BUFKIT PRECIPITATION TYPE ALGORITHMS SUGGEST COULD BE RAIN AND/OR SNOW. ONLY CHANGE TO DATA BASE IN THIS TIME FRAME WAS TO TRIM EASTWARD EXTENT OF PRECIPITATION PROBABILITIES INTO CENTRAL WI ON TUESDAY. .LONG TERM...THURSDAY THROUGH SUNDAY THURSDAY INTO FRIDAY...OPERATIONAL ECMWF AND GFS HAVE COME INTO BETTER CONSENSUS ON CLOSED 500MB LOW ADVANCING FROM OHIO VALLEY INTO EASTERN GREAT LAKES AND SOUTHEAST CANADA. THIS WAS CORROBORATED BY MREF ENSEMBLES. THUS...FORECAST CONFIDENCE INCREASING IN DETAILS WITHIN CURRENT DATA BASE...WHICH SUPPORTS DRY CONDITIONS. SATURDAY INTO SUNDAY...ECMWF AND GFS HAD SIGNIFICANT DIFFERENCES IN THE DETAILS OF UPPER LEVEL AND SURFACE FEATURES. MREF ENSEMBLES SUPPORTED A LESS AMPLIFIED FLOW...THEREFORE FORECAST CONFIDENCE WAS LOW IN THIS TIME FRAME. NO CHANGES WERE MADE IN THE EXTENDED OUTLOOK AND THUS MAINTAINED DRY FORECAST. && .ARX WATCHES/WARNINGS/ADVISORIES... MN...NONE. IA...NONE. WI...NONE. && $$ THOMPSON wi