AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 1018 AM MST SUN OCT 5 2008 SOUTH-CENTRAL AND SOUTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA FORECAST DISCUSSION .UPDATE...UPDATED AVIATION DISCUSSION. && .SYNOPSIS... AFTER LAST NIGHTS SHOWERS AND THUNDERSTORMS MOVED EAST OF THE AREA...HIGH PRESSURE AND A CLEARING TREND IS NOW TAKING OVER. ABUNDANT SUNSHINE WILL PREVAIL ACROSS THE DESERTS TODAY. HIGH TEMPERATURES WILL BE A BIT WARMER TODAY AT MOST LOCATIONS THOUGH STILL BELOW NORMAL. A MORE SUBSTANTIAL WARMING TREND CAN BE EXPECTED MONDAY THROUGH WEDNESDAY AS HIGH PRESSURE BUILDS IN FROM THE WEST. TEMPERATURES WILL ONCE AGAIN BECOME WELL ABOVE NORMAL WITH MANY LOWER DESERT LOCATIONS...INCLUDING THE PHOENIX AREA APPROACHING OR EVEN REACHING 100 DEGREES WEDNESDAY AND THURSDAY. THEREAFTER...A GRADUAL COOLING TREND IS ANTICIPATED AS HIGH PRESSURE WEAKENS. && .DISCUSSION... SHORT WAVE TROUGH WAS LOCATED ALONG A PAGE-SHOW LOW-TUCSON LINE AT MID MORNING WITH A FEW REMNANT SHOWERS TRACKING THROUGH THE WHITE MOUNTAINS. IT WAS AN ACTIVE NIGHT...WITH MUCH MORE PRECIP IN EASTERN AZ THAN I HAD EXPECTED. IN FACT...SHOW LOW HAD .88 INCH AND ROOSEVELT CAME OUT ON TOP WITH A WHOPPING 1.20 INCHES FROM OVERNIGHT THUNDERSTORMS. RUC SEEMED TO HAVE VERY GOOD MOISTURE AND INSTABILITY TRENDS...WITH THE VORT MAX TRYING TO SPLIT INTO TWO PARTS BY 18Z AS IT APPROACHED THE AZ/NEW MEXICO LINE. DRY NORTHWEST FLOW ALOFT IS ALSO FORECAST...AND GFS/NAM APPEAR TO AGREE WITH EACH OTHER MUCH BETTER. THEREFORE...SOME MINOR ADJUSTMENTS...OR CUTBACKS IN POPS WERE NECESSARY EARLIER TODAY. TEMPS STILL LOOK GOOD AND GUIDANCE SHOWS SIMILAR WARMING TRENDS AS BEFORE THROUGH AT LEAST TUESDAY. PREVIOUS DISCUSSION... WEDNESDAY THROUGH SATURDAY...TEMPS WILL GET TO BE WELL ABOVE NORMAL ONCE AGAIN. IN FACT MANY LOWER ELEVATION LOCATIONS INCLUDING THE PHOENIX AREA WILL GET VERY CLOSE TO...IF NOT REACH...100 DEGREES WEDNESDAY AND THURSDAY. THEREAFTER...THE PROGS ARE DEPICTING A WEAKENING OF THE RIDGE. HOWEVER...THERE ARE VERY DIFFERENT SCENARIOS WHEN COMPARING THE OPERATIONAL GFS AND ECMWF. THE GFS PASSES A TROUGH WELL TO THE NORTH WHEREAS THE ECMWF DEVELOPS A DEEP CLOSED LOW OVER THE PACIFIC NORTHWEST. THE GFS ENSEMBLE MEAN IS MUCH CLOSER TO THE OPERATIONAL GFS SOLUTION THOUGH IT HAS A TROUGH AXIS FURTHER TO THE WEST. OVER THE WEEKEND...THE GFS AND ECMWF ARE OUT OF PHASE WITH ONE ANOTHER AS THE GFS HAS A RIDGE OVER THE INTERIOR WEST AND THE ECMWF HAS A DEEP LOW CENTERED OVER THE NORTHERN GREAT BASIN AND SOUTHERN IDAHO. THE 00Z ECMWF DOES NOT TRACK THE LOW AS FAR SOUTH AS THE 12Z RUN. GIVEN THE ANOMALOUS NATURE OF THE ECMWF...LEANING TOWARD THE GFS ENSEMBLE MEAN AND THUS SHOW A MORE GRADUAL COOLING TREND DURING THE LATTER PART OF THE EXTENDED. INTERESTINGLY...BOTH MODELS ARE MUCH CLOSER TO ONE ANOTHER IN HOW THEY DEPICT A TROPICAL STORM MOVING INTO SOUTHERN BAJA MEXICO. && .AVIATION... KPHX AND KIWA... SKIES HAVE CLEARED FROM WEST TO EAST...WITH ONLY A FEW MID-LEVEL CLOUDS PERSISTING THROUGH THE AFTERNOON. MUCH LESS WIND EXPECTED COMPARED TO YESTERDAY...WITH DIRECTIONS FAVORING THE WEST ALL DAY. TYPICAL DIURNAL WINDS WILL RETURN OVERNIGHT. KYUM/KIPL AND KBLH...MUCH LESS WIND EXPECTED TODAY AS COMPARED TO SATURDAY...WITH DIRECTIONS FAVORING THE WEST THRU NORTH. SPEEDS SHOULD GENLY BE 5-15KT. BY EARLY EVE WINDS SHOULD DIMINISH AND BECOME LARGELY LIGHT VARIABLE OR DIURNAL...AGAIN TENDING TO FAVOR THE NW TO N. GENLY CLEAR SKIES ON TAP NEXT 24 HOURS AT LEAST. && .FIRE WEATHER... TUESDAY THROUGH SATURDAY... A HIGH PRESSURE SYSTEM WILL DOMINATE THE REST OF THE WEEK...BRINGING MOSTLY CLEAR SKIES TO THE REGION. EXPECT LIGHT WINDS AND DRIER CONDITIONS...WITH MINIMUM HUMIDITY VALUES DROPPING BELOW 15 PERCENT ACROSS SOUTH-CENTRAL ARIZONA AND SOUTHEAST CALIFORNIA THROUGH THE WEEKEND. DECENT RECOVERY EXPECTED EACH NIGHT...WITH MAX RH VALUES RISING TO BETWEEN 30 AND 50 PERCENT. NO SIGNIFICANT FIRE WEATHER ISSUES EXPECTED DURING THE PERIOD. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && $$ NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT WEATHER.GOV/PHOENIX DISCUSSION...SIPPLE AVIATION...ROGERS/CB FIRE WEATHER...CB az AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PUEBLO CO 317 PM MDT SUN OCT 5 2008 .SHORT TERM... (TONIGHT AND MONDAY) UPPER TROUGH CROSSING THE STATE THIS AFTERNOON...WITH STRONG SHORT WAVE ROUNDING THE BASE OF THE TROUGH IN SOUTHERN NEW MEXICO EJECTING INTO WESTERN TX. SURFACE LOW HAS REMAINED NEARLY STATIONARY BETWEEN KPUB AND KCOS...WITH REGIONAL RADAR LOOP INDICATING CONVECTION BREAKING OUT ALONG THE COLD FRONT FROM KCOS NORTHEAST TO NEAR KMCK AS OF 20Z. BEST UPWARD MOTION HAS SHIFTED SOUTH AND EAST OF THE CONTINENTAL DIVIDE THIS AFTERNOON...THOUGH STILL A GOOD AMOUNT OF CONVECTION UNDER THE COLD POOL OVER THE MOUNTAINS. WILL LET WINTER WEATHER ADVISORY DIE AT 3 PM AS THREAT OF WIDESPREAD ACCUMULATING SNOW HAS ENDED...THOUGH BE A FEW BURSTS OF BRIEF HEAVY SNOW ABOVE 11K FEET ARE POSSIBLE THROUGH SUNSET. ATTENTION THIS EVENING THROUGH MONDAY TURNS TO THE EASTERN PLAINS...AS UPPER LOW SLOWLY CLOSES OFF OVER WESTERN KS EARLY MONDAY. BOTH RUC AND NAM SUGGEST SURFACE LOW WILL SLOWLY DRIFT SOUTHEAST THROUGH THE EVENING...WITH COLD FRONT MAKING A RATHER WEAK PUSH TO SOMEWHERE SOUTH OF THE ARKANSAS RIVER BY 06Z. FRONT THEN ACCELERATES SOUTHWARD MONDAY MORNING...WITH INCREASING NORTHERLY WINDS ACROSS MOST OF THE PLAINS DURING THE DAY. BEST UPWARD MOTION OVER THE EASTERN MOUNTAINS AND I-25 CORRIDOR APPEARS TO BE LATE THIS AFTERNOON AND THIS EVENING...ESPECIALLY NORTH OF THE FRONTAL BOUNDARY WHERE MOISTURE DEEPENS AND WINDS BECOME AT LEAST WEAKLY UPSLOPE. ISENTROPIC LIFT WRAPS AROUND THE LOW MONDAY MORNING...WHICH SHOULD KEEP PRECIP GOING OVER THE FAR EASTERN PLAINS FROM ROUGHLY 06Z-18Z...THOUGH STRONGEST LIFT IS NORTH AND EAST OF THE AREA. OVERALL TREND OF THE GRIDS LOOKED GOOD...MAIN CHANGES WERE TO END PRECIP FROM WEST TO EAST SLIGHTLY FASTER OVERNIGHT AND EARLY MONDAY. PETERSEN .LONG TERM... (MONDAY NIGHT THROUGH SUNDAY) ...ANOTHER POTENTIAL SYSTEM SETTING UP FOR NEXT WEEKEND... MONDAY NIGHT...THE UPPER TROUGH IS FORECAST TO BE MOVING EAST ACROSS THE CENTRAL PLAINS BY MON EVE...ALLOWING FOR COLD DRY AIR TO SWEEP ACROSS THE CWA MON NIGHT. RAPIDLY CLEARING SKIES COULD MAKE FOR A COLD NIGHT WITH PATCHY FROST ACROSS THE PALMER DIVIDE AND LOWER ARKANSAS RIVER VALLEY. ONLY OTHER THING TO NOTE WILL BE BRISK N WINDS OVER THE FAR EASTERN PLAINS DUE TO WRAPAROUND WHICH SHOULD DIMINISH AS THE NIGHT WEARS ON. TUESDAY THROUGH FRIDAY...NEAR ZONAL FLOW ACROSS THE ROCKY MT REGION FOR TUE THRU THUR AS A FLAT RIDGE BUILDS INTO THE DESERT SW. ESSENTIALLY DRY CONDITIONS WITH GRADUAL WARMING THROUGH THE WEEK. GFS AND ECMWF IS HINTING AT THE POTENTIAL OF SOME PCPN ACROSS THE E PLAINS THU...DUE TO SFC HIGH PRES DROPPING DOWN INTO THE CENTRAL PLAINS AND BACKDOORING INTO CO. FOR NOW INCREASED CLOUD COVER AND MIN TEMPS SLIGHTLY THU NIGHT AND HELD OFF INTRODUCING ANY POPS...BUT THIS WILL NEED TO BE WATCHED FOR MODEL CONSISTENCY. ON FRI THE NEXT UPPER TROUGH DROPS DOWN INTO MT...DIPPING INTO WY BY FRI EVE. IF THE TIMING AND POSITION IS FORECAST CORRECTLY...THIS WILL MEAN A WARM DAY FOR MUCH OF THE CWA AS SW WINDS ALOFT INCREASE AND ASSOC PCPN STAYS NORTH OF COLORADO THRU THE DAY. CURRENT POP GRIDS HAVE ISOLATED POPS OVER THE CENT MTS IN THE AFTN...THEN ISOLATED POPS ALL AREAS FRI NIGHT. FOR NOW THIS SEEMS REASONABLE...BUT WILL GET ADJUSTED AS THE EVENT NEARS. SATURDAY AND SUNDAY...ECMWF AND GFS LONG RANGE MODELS ARE STILL UNCERTAIN ON HOW TO HANDLE THE NEXT STORM SYSTEM...SO FORECAST CONFIDENCE IS LOW. FEEL CONFIDENT IN SAYING THAT NEXT WEEKEND WILL FEEL MORE LIKE FALL WITH MUCH COLDER TEMPS...BUT PCPN TYPE AND AMOUNTS ARE STILL UP IN THE AIR. MOORE && .AVIATION... SURFACE BOUNDARY LIES BETWEEN KCOS AND KPUB AT 21Z...AND SHOULD SINK SLOWLY SOUTH TO SOUTH OF KPUB AROUND 00Z. WINDOW FOR TSRA AT KCOS SHOULD RUN FROM ABOUT 22Z THROUGH 04Z...AND FROM 00Z THROUGH 05Z AT KPUB. STILL SOME ISOLATED SHOWERS POSSIBLE AT BOTH SITES INTO EARLY MONDAY MORNING...WITH ANY PRECIP SHIFTING EAST OF THE I-25 CORRIDOR AFTER 12Z. MOISTURE REMAINS FAIRLY LIMITED...SO ONLY VERY BRIEF MVFR CONDITIONS AT WORST WITH ANY CONVECTION THIS EVENING AND OVERNIGHT. OVER THE MOUNTAINS...FAIRLY WIDESPREAD CONVECTION THIS AFTERNOON...THOUGH WEB CAMS SUGGEST OBSCURATION OF HIGHER TERRAIN IS RATHER PATCHY. EXPECT MOST CONVECTION TO DIE OUT AFTER SUNSET OVER ALONG AND WEST OF THE SANGRES...INCLUDING KALS...WHILE THICKER CLOUDS AND SOME SHOWERS WILL HANG OVER THE SAWATCH AND MOSQUITO RANGES THROUGH EARLY MONDAY MORNING. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 10/27 co AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 927 PM EDT MON OCT 6 2008 .SYNOPSIS... AN AREA OF CANADIAN HIGH PRESSURE WILL MOVE ACROSS THE NORTHEAST THROUGH WEDNESDAY. THIS WILL ALLOW FOR CHILLY MORNINGS AND INCREASINGLY WARMER AFTERNOONS ACROSS THE REGION FOR TUESDAY AND WEDNESDAY. A FRONTAL BOUNDARY WILL APPROACH THE AREA ON THURSDAY...BRINGING THE CHANCE FOR A FEW SHOWERS. && .NEAR TERM /UNTIL 8 AM TUESDAY MORNING/... UPPER LEVEL TROUGH IS NOW WELL EAST OF THE REGION ACROSS THE GULF OF MAINE...ALLOWING FOR RIDGING ACROSS THE GREAT LAKES TO SHIFT TOWARDS OUR REGION. LATEST SATELLITE PICTURE SHOWS CLEAR SKIES CWA WIDE AND PLENTY OF DRY AIR AT MID LEVELS ACCORDING TO H20 LOOP AS WELL. THIS HAS ALLOWED TEMPERATURES TO RAPIDLY FALL IN MOST AREAS THIS EVENING. BOUNDARY LAYER IS JUST A BIT MORE MOIST THAN MODELS HAVE PROJECTED...WHICH COULD ALLOW FOR SOME PATCHY FOG TO BRIEFLY DEVELOP OVERNIGHT AT USUAL SUSPECT PLACES. HOWEVER...00Z ALY SOUNDING SHOWS A HIGH INVERSION HEIGHT /AROUND 800 MB/ WITH ABOUT 20 KTS OF WIND FROM JUST ABOVE THE DECK UP TO THE INVERSION LEVEL. WOULD THINK THAT THIS COULD HELP MIX AIR SOMEWHAT ENOUGH TO PREVENT ANY WIDESPREAD FOG FROM DEVELOPING TONIGHT. WITH WEAK CAA CURRENTLY ONGOING...WOULDN/T BE SURPRISED IF TDS CONTINUED TO DROP THROUGH THE FIRST HALF OF THE NIGHT AS WELL. AT THIS POINT...WILL LEAVE FORECASTED MINS ALONE AND ONLY DO A MINOR UPDATE TO ACCOUNT FOR CURRENT TRENDS. ACCORDINGLY...WILL CONTINUE CURRENT FREEZE/FROST HEADLINES AS IS...SEEING NO NEED TO MESS WITH THEM AT THIS TIME. && .SHORT TERM /8 AM TUESDAY MORNING THROUGH THURSDAY/... NOT SO SURE HOW COLD IT WILL GET TUESDAY NIGHT. MAV GUIDANCE BY FAR THE COLDEST AND BELIEVE THAT IS OVERDONE. WARMING WILL BE OCCURRING ALOFT WITH 850 MB TEMPERATURES EXPECTED TO WARM TO 8 TO 10 DEGREES CELSIUS BY 12Z/WEDNESDAY. PLUS SOME HIGH LEVEL CLOUDS MAY REACH THE REGION. SURFACE HIGH WILL MOVE OFF REGION AND WINDS WILL BE LIGHT AND VARIABLE. WHERE GROWING SEASON DOES NOT END TONIGHT WILL NEED FREEZE WARNINGS AND/OR FROST ADVISORIES FOR TUESDAY NIGHT. THE SURFACE HIGH WILL SLIDE OFF TO OUR SOUTH AND EAST WEDNESDAY AND THE UPPER RIDGE AXIS WILL SHIFT TO THE EAST. TEMPERATURES WILL BEGIN TO MODERATE. AFTER A COLD START TEMPERATURES WILL REBOUND TO ABOVE NORMAL LEVELS. HIGHER LEVEL CLOUDS WILL MOVE IN AHEAD OF A FRONTAL BOUNDARY WHICH IS EXPECTED TO CROSS THE REGION THURSDAY. MODEL SOLUTIONS REALLY BEGIN TO DIVERGE BY THURSDAY. EXPECT ANOTHER MILD DAY WITH ABOVE NORMAL TEMPERATURES THURSDAY ALONG WITH A CHANCE FOR SHOWERS. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AROUND THE START OF THE EXTENDED PERIOD...A FRONTAL SYSTEM IN THE NORTHERN STREAM WILL BE PUSHING THROUGH THE NORTHEAST. HAVE TAPERED OFF POPS THROUGH THE NIGHT AS THE BEST FORCING WILL BE MOVING EAST OF THE REGION. MIN TEMPS WILL BE HELD SEVERAL DEGREES ABOVE SEASONAL NORMALS AS THE ASSOCIATED CLOUD COVER AND SHOWER ACTIVITY WILL HELP KEEP TEMPS FROM DROPPING TOO MUCH. THE WEEKEND PERIOD IS NOT BEING HANDLED TOO WELL BY THE MODELS AT THIS POINT. BOTH THE ECMWF AND GFS HAVE BEEN HOLDING STEADY ON THEIR VARIOUS PATTERNS FOR SEVERAL RUNS NOW. THE GFS IS DETERMINED TO BRING A CUTOFF NORTHEASTWARD FROM THE SOUTHEAST FRIDAY AND UP THE ATLANTIC COAST FOR THE WEEKEND. THIS WOULD BRING AN AREA OF SHOWERS TO THE REGION FOR SOMETIME FRIDAY NIGHT INTO SATURDAY NIGHT. MEANWHILE...THE ECMWF HAS CONTINUED TO SHOW STRONG HIGH PRESSURE AT THE SURFACE DEVELOPING ACROSS THE GREAT LAKES ON FRIDAY...WHICH WOULD SPREAD EASTWARD OVER THE WEEKEND...KEEPING THE CUTOFF SUPPRESSED ACROSS THE SOUTHEAST. WILL TEND TO FAVOR THE ECMWF SOLUTION...WHICH HAS SUPPORT FROM BOTH THE 12Z UKMET AND 12Z GGEM. STILL...TO ACCOUNT FOR THE UNCERTAINTY AND TO PRESERVE SOME CONTINUITY WITH PREVIOUS FORECASTS...WILL STILL HOLD LOW CHC POPS FOR A BRIEF PERIOD FOR SOUTHERN AND EASTERN AREAS OF THE CWA OVER THE WEEKEND. WILL KEEP TEMPS A FEW DEGREES ABOVE NORMAL...AS STRONG RIDGING DEPICTED BY ECMWF WOULD ALLOW FOR TEMPS TO AVERAGE WARMER THAN SEASONAL NORMALS. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... TRICKY CALL ON VSBYS OVERNIGHT...ESP OVER THE NEXT 1-3 HOURS...AS TEMP/DEWPOINT SPREADS ARE NEARING ZERO F ALREADY AT KGFL...AND ARE WITHIN 3F AT KALB. CURRENT THINKING IS THAT DRIER AIR WILL GRADUALLY WORK DOWNWARD LATER THIS EVENING...LIMITING OVERALL GROUND FOG POTENTIAL TO EARLY THIS EVENING. AS SUCH...HAVE ONLY INDICATED A BRIEF TEMPO GROUP FOR IFR VSBY AT KGFL...WITH NO REDUCTIONS ELSEWHERE. THIS SEEMS TO BE SUPPORTED BY LATEST RUC13...WHICH DEPICTS DRYING AT THE TOP OF THE BOUNDARY LAYER OVER THE NEXT 2-4 HOURS...ALONG WITH AN INCREASE IN WINDS UP TO 20-30KT AT 90MB AGL. SHOULD THESE WINDS FAIL TO DEVELOP...A MORE PROLONGED AND WIDESPREAD GROUND FOG EVENT MAY OCCUR AT KGFL AND KALB...BUT CURRENT THINKING IS THAT THIS IS ONLY A SMALL POSSIBILITY. VFR CONDITIONS ARE THEN EXPECTED THROUGHOUT TUE. WINDS WILL MAINLY BE FROM THE NORTH OVERNIGHT AND TUESDAY...AT LESS THAN 5 KT TONIGHT...THEN 5-10 KT ON TUE. LOCAL VARIATIONS IN WIND DIRECTION ARE POSSIBLE TUE AFTERNOON DUE TO TOPOGRAPHICAL INFLUENCES...ESP AT KGFL...WHICH MAY BECOME NORTHEAST TO EAST AT TIMES. OUTLOOK... TUE-WED...VFR...NO SIG WX. THU-SAT...VFR/MVFR...CHC SHOWERS. && .FIRE WEATHER... COOL CANADIAN HIGH PRESSURE WILL BUILD SOUTHWARD INTO THE REGION AND WILL DOMINATE OUR WEATHER THROUGH MID WEEK. TEMPERATURES WILL BEGIN TO MODERATE DURING THE DAY WEDNESDAY AS THE HIGH SHIFTS OFF TO OUR SOUTHEAST AND A SOUTHERLY FLOW OF WARMER AIR DEVELOPS. THE RELATIVE HUMIDITY WILL RECOVER TO 90 TO NEAR 100 PERCENT TONIGHT AND DROP TO MINIMUMS OF 30 TO 40 TUESDAY AFTERNOON. LIGHT NORTHWESTERLY WINDS TONIGHT INCREASING TO 5 TO 10 MPH TUESDAY THEN DIMINISHING IN THE EVENING. && .HYDROLOGY... NO HYDRO PROBLEMS ANTICIPATED FOR THE NEXT SEVERAL DAYS. COOL CANADIAN HIGH PRESSURE WILL BUILD SOUTHWARD INTO THE REGION AND WILL DOMINATE OUR WEATHER THROUGH MID WEEK. TEMPERATURES WILL BEGIN TO MODERATE DURING THE DAY WEDNESDAY AS THE HIGH SHIFTS OFF TO OUR SOUTHEAST AND A SOUTHERLY FLOW OF WARMER AIR DEVELOPS. OUR NEXT CHANCES FOR RAIN WILL COME LATE IN THE WEEK WHEN A FRONTAL BOUNDARY IS EXPECTED TO MOVE ACROSS THE REGION. FOR DETAILS ON THE RIVERS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...FROST ADVISORY UNTIL 9 AM EDT TUESDAY FOR CTZ001-013. NY...FREEZE WARNING UNTIL 9 AM EDT TUESDAY FOR NYZ038>043-047-048- 051-054-061-063-066-083-084. FROST ADVISORY UNTIL 9 AM EDT TUESDAY FOR NYZ049-050-052-053- 059-060-064-065. MA...FREEZE WARNING UNTIL 9 AM EDT TUESDAY FOR MAZ025. VT...FREEZE WARNING UNTIL 9 AM EDT TUESDAY FOR VTZ014-015. && $$ SYNOPSIS...FRUGIS NEAR TERM...FRUGIS SHORT TERM...IAA LONG TERM...FRUGIS AVIATION...KL FIRE WEATHER...IAA HYDROLOGY...IAA ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ALBANY NY 737 PM EDT MON OCT 6 2008 .SYNOPSIS... COOL CANADIAN HIGH PRESSURE WILL BUILD SOUTHWARD INTO THE REGION AND WILL DOMINATE OUR WEATHER THROUGH MID WEEK. TUESDAY AND WEDNESDAY MORNINGS WILL START OUT COLD. TEMPERATURES WILL BEGIN TO MODERATE DURING THE DAY WEDNESDAY AS THE HIGH SHIFTS OFF TO OUR SOUTHEAST AND A SOUTHERLY FLOW OF WARMER AIR DEVELOPS. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... AS OF 730 PM EDT...DEWPOINTS HAVE BEEN SLOW TO DROP WITHIN THE VALLEYS...AND ARE SLOWLY DROPPING ACROSS THE HIGHER TERRAIN...AS THE DRIER AIR WORKS DOWNWARD IN ELEVATION. WE EXPECT THE DEWPOINTS TO GRADUALLY LOWER OVER THE NEXT 2-4 HOURS...AS STRONG SUBSIDENCE CONTINUES IN THE WAKE OF POTENT SHORTWAVE PASSING TO OUR S/E. IN ADDITION...RUC13 DEPICTS WINDS STRENGTHENING AT THE TOP OF THE BOUNDARY LAYER OVER THE NEXT SEVERAL HOURS...WHICH SHOULD HELP ENTRAIN THE DRIER AIR DOWNWARD A BIT LATER TONIGHT. UNTIL THEN...SOME PATCHY FOG COULD BRIEFLY DEVELOP. RIDGE FINALLY BUILDS IN AT ALL LEVELS LATER TONIGHT...WITH LIGHT N-NW FLOW ON THE EAST SIDE OF RIDGE. COLD POOL SHIFTS TO THE EAST WITH TROUGH AXIS. WEAK WARMING OCCURS ALOFT LATER TONIGHT. MOS GUIDANCE IS IN FAIRLY GOOD AGREEMENT FOR TONIGHT...WILL BE A COLD ONE. BLENDED THE FORECAST LOWS INHERITED WITH LATEST MODEL GUIDANCE WHICH RESULTED IN MINOR ADJUSTMENTS...A TAD WARMER IN SOME LOCALES. HOWEVER...NO CHANGES NEEDED TO CURRENT FREEZE WARNINGS AND FROST ADVISORIES. THE GROWING SEASON SHOULD END ACROSS MUCH OF THE FORECAST AREA TONIGHT. THE HUDSON VALLEY UP TO THE IMMEDIATE CAPITAL DISTRICT AND LITCHFIELD COUNTY CT TEMPERATURES SHOULD FALL JUST SHORT OF REACHING THE FREEZING MARK. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... NOT SO SURE HOW COLD IT WILL GET TUESDAY NIGHT. MAV GUIDANCE BY FAR THE COLDEST AND BELIEVE THAT IS OVERDONE. WARMING WILL BE OCCURRING ALOFT WITH 850 MB TEMPERATURES EXPECTED TO WARM TO 8 TO 10 DEGREES CELSIUS BY 12Z/WEDNESDAY. PLUS SOME HIGH LEVEL CLOUDS MAY REACH THE REGION. SURFACE HIGH WILL MOVE OFF REGION AND WINDS WILL BE LIGHT AND VARIABLE. WHERE GROWING SEASON DOES NOT END TONIGHT WILL NEED FREEZE WARNINGS AND/OR FROST ADVISORIES FOR TUESDAY NIGHT. THE SURFACE HIGH WILL SLIDE OFF TO OUR SOUTH AND EAST WEDNESDAY AND THE UPPER RIDGE AXIS WILL SHIFT TO THE EAST. TEMPERATURES WILL BEGIN TO MODERATE. AFTER A COLD START TEMPERATURES WILL REBOUND TO ABOVE NORMAL LEVELS. HIGHER LEVEL CLOUDS WILL MOVE IN AHEAD OF A FRONTAL BOUNDARY WHICH IS EXPECTED TO CROSS THE REGION THURSDAY. MODEL SOLUTIONS REALLY BEGIN TO DIVERGE BY THURSDAY. EXPECT ANOTHER MILD DAY WITH ABOVE NORMAL TEMPERATURES THURSDAY ALONG WITH A CHANCE FOR SHOWERS. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AROUND THE START OF THE EXTENDED PERIOD...A FRONTAL SYSTEM IN THE NORTHERN STREAM WILL BE PUSHING THROUGH THE NORTHEAST. HAVE TAPERED OFF POPS THROUGH THE NIGHT AS THE BEST FORCING WILL BE MOVING EAST OF THE REGION. MIN TEMPS WILL BE HELD SEVERAL DEGREES ABOVE SEASONAL NORMALS AS THE ASSOCIATED CLOUD COVER AND SHOWER ACTIVITY WILL HELP KEEP TEMPS FROM DROPPING TOO MUCH. THE WEEKEND PERIOD IS NOT BEING HANDLED TOO WELL BY THE MODELS AT THIS POINT. BOTH THE ECMWF AND GFS HAVE BEEN HOLDING STEADY ON THEIR VARIOUS PATTERNS FOR SEVERAL RUNS NOW. THE GFS IS DETERMINED TO BRING A CUTOFF NORTHEASTWARD FROM THE SOUTHEAST FRIDAY AND UP THE ATLANTIC COAST FOR THE WEEKEND. THIS WOULD BRING AN AREA OF SHOWERS TO THE REGION FOR SOMETIME FRIDAY NIGHT INTO SATURDAY NIGHT. MEANWHILE...THE ECMWF HAS CONTINUED TO SHOW STRONG HIGH PRESSURE AT THE SURFACE DEVELOPING ACROSS THE GREAT LAKES ON FRIDAY...WHICH WOULD SPREAD EASTWARD OVER THE WEEKEND...KEEPING THE CUTOFF SUPPRESSED ACROSS THE SOUTHEAST. WILL TEND TO FAVOR THE ECMWF SOLUTION...WHICH HAS SUPPORT FROM BOTH THE 12Z UKMET AND 12Z GGEM. STILL...TO ACCOUNT FOR THE UNCERTAINTY AND TO PRESERVE SOME CONTINUITY WITH PREVIOUS FORECASTS...WILL STILL HOLD LOW CHC POPS FOR A BRIEF PERIOD FOR SOUTHERN AND EASTERN AREAS OF THE CWA OVER THE WEEKEND. WILL KEEP TEMPS A FEW DEGREES ABOVE NORMAL...AS STRONG RIDGING DEPICTED BY ECMWF WOULD ALLOW FOR TEMPS TO AVERAGE WARMER THAN SEASONAL NORMALS. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... TRICKY CALL ON VSBYS OVERNIGHT...ESP OVER THE NEXT 1-3 HOURS...AS TEMP/DEWPOINT SPREADS ARE NEARING ZERO F ALREADY AT KGFL...AND ARE WITHIN 3F AT KALB. CURRENT THINKING IS THAT DRIER AIR WILL GRADUALLY WORK DOWNWARD LATER THIS EVENING...LIMITING OVERALL GROUND FOG POTENTIAL TO EARLY THIS EVENING. AS SUCH...HAVE ONLY INDICATED A BRIEF TEMPO GROUP FOR IFR VSBY AT KGFL...WITH NO REDUCTIONS ELSEWHERE. THIS SEEMS TO BE SUPPORTED BY LATEST RUC13...WHICH DEPICTS DRYING AT THE TOP OF THE BOUNDARY LAYER OVER THE NEXT 2-4 HOURS...ALONG WITH AN INCREASE IN WINDS UP TO 20-30KT AT 90MB AGL. SHOULD THESE WINDS FAIL TO DEVELOP...A MORE PROLONGED AND WIDESPREAD GROUND FOG EVENT MAY OCCUR AT KGFL AND KALB...BUT CURRENT THINKING IS THAT THIS IS ONLY A SMALL POSSIBILITY. VFR CONDITIONS ARE THEN EXPECTED THROUGHOUT TUE. WINDS WILL MAINLY BE FROM THE NORTH OVERNIGHT AND TUESDAY...AT LESS THAN 5 KT TONIGHT...THEN 5-10 KT ON TUE. LOCAL VARIATIONS IN WIND DIRECTION ARE POSSIBLE TUE AFTERNOON DUE TO TOPOGRAPHICAL INFLUENCES...ESP AT KGFL...WHICH MAY BECOME NORTHEAST TO EAST AT TIMES. OUTLOOK... TUE-WED...VFR...NO SIG WX. THU-SAT...VFR/MVFR...CHC SHOWERS. && .FIRE WEATHER... COOL CANADIAN HIGH PRESSURE WILL BUILD SOUTHWARD INTO THE REGION AND WILL DOMINATE OUR WEATHER THROUGH MID WEEK. TEMPERATURES WILL BEGIN TO MODERATE DURING THE DAY WEDNESDAY AS THE HIGH SHIFTS OFF TO OUR SOUTHEAST AND A SOUTHERLY FLOW OF WARMER AIR DEVELOPS. THE RELATIVE HUMIDITY WILL RECOVER TO 90 TO NEAR 100 PERCENT TONIGHT AND DROP TO MINIMUMS OF 30 TO 40 TUESDAY AFTERNOON. LIGHT NORTHWESTERLY WINDS TONIGHT INCREASING TO 5 TO 10 MPH TUESDAY THEN DIMINISHING IN THE EVENING. && .HYDROLOGY... NO HYDRO PROBLEMS ANTICIPATED FOR THE NEXT SEVERAL DAYS. COOL CANADIAN HIGH PRESSURE WILL BUILD SOUTHWARD INTO THE REGION AND WILL DOMINATE OUR WEATHER THROUGH MID WEEK. TEMPERATURES WILL BEGIN TO MODERATE DURING THE DAY WEDNESDAY AS THE HIGH SHIFTS OFF TO OUR SOUTHEAST AND A SOUTHERLY FLOW OF WARMER AIR DEVELOPS. OUR NEXT CHANCES FOR RAIN WILL COME LATE IN THE WEEK WHEN A FRONTAL BOUNDARY IS EXPECTED TO MOVE ACROSS THE REGION. FOR DETAILS ON THE RIVERS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEBSITE. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EDT TUESDAY FOR CTZ001-013. NY...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT TUESDAY FOR NYZ038>043-047-048-051-054-061-063-066-083-084. FROST ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EDT TUESDAY FOR NYZ049-050-052-053-059-060-064-065. MA...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT TUESDAY FOR MAZ025. VT...FREEZE WARNING FROM MIDNIGHT TONIGHT TO 9 AM EDT TUESDAY FOR VTZ014-015. && $$ SYNOPSIS...IAA NEAR TERM...KL/IAA SHORT TERM...IAA LONG TERM...FRUGIS AVIATION...KL FIRE WEATHER... HYDROLOGY...IAA ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE UPTON NY 144 PM EDT MON OCT 6 2008 .SYNOPSIS... STRONG HIGH PRESSURE WILL BUILD DOWN FROM ONTARIO THROUGH TONIGHT...THEN MOVE OFFSHORE THURSDAY. LOW PRESSURE OVER THE TENNESSEE VALLEY ON THURSDAY WILL MOVE OFF THE MIDDLE ATLANTIC COAST ON FRIDAY AND MOVE TOWARDS THE REGION FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... DEPARTING JET STREAK AND 850-700 FRONTOGENETIC REGION ALLOWING FOR SOME BRIEF CLEARING EARLY THIS AFTERNOON...BUT 500 MB VORT TRACKING SE FROM UPSTATE NY THIS AFTERNOON WILL BRING A RETURN TO PARTLY SUNNY/MOSTLY CLOUDY SKY CONDITIONS AT MOST LOCATIONS THIS AFTERNOON. BEST FORCING WILL BE OVER NE PORTIONS OF THE CWA...SO LEFT IN CHANCE OF SPRINKLES OVER SE CT THIS AFTERNOON...OTHERWISE DRY. BASICALLY FOLLOWED THE RUC FOR THIS UPDATE AS IT HAS BEST HANDLE ON 500 MB VORT. TEMPERATURE FORECAST GENERALLY ON TRACK...MADE MINOR CHANGES TO REFLECT LATEST HOURLY TRENDS. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... STRONG SUBSIDENCE LEADING TO CLEAR SKIES BY THIS EVENING. WINDS DIMINISH AND EXPECT MOST AREAS TO DECOUPLE AND GO CALM...ESPECIALLY INTERIOR SECTIONS. THIS WILL PROVIDE AND EXCELLENT SETUP FOR FROST. A FROST ADVISORY IS UP FOR THE OUTER ZONES IN NY/NJ AND CT FOR AFTER MIDNIGHT TONIGHT. SUFFOLK COUNTY ON LONG ISLAND IS QUESTIONABLE WITH HOW COLD THE PINE BARREN REGION CAN GET. HOWEVER IT WILL BE A LITTLE MORE DIFFICULT TO DECOUPLE HERE...AND THE AREA THAT DOES GET FROST IS TOO SMALL TO WARRANT A FROST ADVISORY FOR THE SURROUNDING ZONE. GUIDANCE TEMPS LOOK GOOD...BUT FAVORED THE SLIGHTLY COOLER MET OVER THE MAV. HIGH PRESSURE SOLIDLY IN CONTROL WITH SKC TUESDAY...AND MAYBE A FEW POPCORN CU WEDNESDAY. COOL TEMPS WITH DAYTIME HIGHS IN THE UPPER 50S TO MID 60S. TUESDAY NIGHT MAY BE THE END OF THE GROWING SEASON FOR MOST AREAS AWAY FROM THE COAST WITH A FREEZE POSSIBLE UNDER IDEAL RADIATIONAL COOLING CONDITIONS. LOWS RANGE FROM LOW 30S INLAND TO UPPER 40S NEAR THE OCEAN. THE SURFACE HIGH SLIDES EAST OFF THE COAST AND LETS RETURN FLOW AND MID LEVEL MOISTURE WORK IN FROM THE WEST THURSDAY...WITH SLIGHTLY WARMER TEMPS. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... LARGE DIFFERENCES IN THE MEDIUM RANGE MODELS FOR LATER THIS WEEK. BOTH THE EC AND GFS HAVE SIMILAR HEIGHT FIELDS....BUT THE FEATURES IN THE EC ARE ABOUT 500 MILES WEST OF THE GFS. BOTH MODELS DRIVE A STRONG PACIFIC JET ACROSS THE NORTHERN US...AND DEVELOP A CUTOFF LOW OVER THE LOWER MS VALLEY BY THURSDAY MORNING. HOWEVER...THE GFS HAS A MUCH MORE PROGRESSIVE FLOW AND BRINGS THAT LOW RACING UP THE US EAST COAST FRIDAY NIGHT ON STRONG SW FLOW AHEAD OF A FULL LATITUDE TROUGH OVER THE CENTRAL PLAINS. THE EC KEEPS THIS DEEP TROUGH AS A CUTOFF OVER THE GREAT BASIN RIGHT THROUGH THE WEEKEND...AND THE INCIPIENT CUTOFF OVER THE SE US. THE RESULT OF ALL THIS IS A COMPLETELY DIFFERENT FORECAST FOR THE TRI STATE AREA FOR THE FRIDAY-SUNDAY PERIOD. WILL HAVE TO MONITOR THE PROGRESS OF THE PACIFIC JET ENERGY TO DELINEATE THE IMPACT ON THIS WEEKENDS WEATHER. HAVE LEFT CHANCE POPS IN THE FORECAST DUE TO THE UNCERTAINTY AT THIS POINT. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... VFR THROUGH THE TAF PERIOD. WILL HAVE A BRIEF PERIOD OF BKN 050-100 DEVELOPING FROM N TO S FROM 19-20Z THEN DISSIPATING AROUND SUNSET. WILL BE SKC AFTER THAT. FOR WINDS...OBSERVATIONS NOT SHOWING GUSTINESS ORIGINALLY ADVERTISED FOR THIS AFTERNOON...EXCEPT AT HIGHER ELEVATIONS...SO HAVE REMOVED FROM TAFS. STILL CANNOT RULE OUT ONE TO TWO HORS OF GUSTS OF 15 TO 20 KT...BUT NOT ENOUGH CONFIDENCE TO REFLECT IN TAFS. WINDS WILL BECOME NW AT ALL TERMINALS WITHIN THE NEXT 2-3 HOURS AT AROUND 10 KT (FROM NW TO SE)...THEN BECOME NORTHERLY AT AROUND 5 KT (LIGHT AND VARIABLE NORTHERN LOWER HUDSON VALLEY TERMINALS AND KTEB) OVERNIGHT...THEN PICK BACK UP OUT OF THE NW AT AROUND 10 KT BY MID MORNING. OUTLOOK FOR 18Z TUESDAY THROUGH SATURDAY... VFR THROUGH THURSDAY. A SLOW MOVING STORM SYSTEM WILL POSSIBLY BRING SUB-VFR CONDITIONS FROM THURSDAY NIGHT INTO SATURDAY...DEPENDING ON ITS EXACT TRACK. A LOW CONFIDENCE FORECAST IN THE EXTENDED FOR THE WEEKEND. && .MARINE... MINOR CHANGES MADE...MAINLY TO PRECIPITATION FORECAST. PREVIOUS DISCUSSION FOLLOWS... AN UPPER LEVEL SHORTWAVE WILL PUSH ACROSS THE AREA WATERS LATE THIS AFTERNOON/EVENING. MEANWHILE...HIGH PRESSURE WILL BUILD IN AT THE SURFACE. AS A RESULT...WINDS WILL INCREASE TO AROUND 15KT...WITH GUSTS BETWEEN 20 AND 25 KT THIS EVENING AND INTO THE FIRST HALF OF THE OVERNIGHT PERIOD. SEAS ARE ALSO EXPECTED TO INCREASE TO 3-4 FT. IT LOOKS LIKE A MARGINAL EVENT FOR SMALL CRAFT CONDITIONS AS FAR AS WINDS ARE CONCERNED. AT THIS TIME...WE HAVE DECIDED TO HOLD OFF ON ANY SCA FOR NOW AND WILL MENTION OCCASIONAL GUSTS UP TO 25KT. WINDS AND WAVES ARE FORECAST TO SUBSIDE TUESDAY WITH STRONG HIGH PRESSURE IN PLACE. QUIET IN THE LONG TERM UNTIL PERHAPS THE VERY END OF THE FORECAST PERIOD...AS A WAVE OF LOW PRESSURE MOVING UP THE COAST COULD TIGHTEN UP THE PRESSURE GRADIENT ENOUGH TO BUILD SEAS TO SCA CRITERIA LATE FRI NIGHT. && .HYDROLOGY... NO MAJOR HYDROLOGY CONCERNS THROUGH THE FCST PERIOD ATTM. A SYSTEM MAY IMPACT THE AREA BY THE END OF THE WEEK INTO THE WEEKEND. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...FROST ADVISORY FROM 2 AM TO 10 AM EDT TUESDAY FOR CTZ005>008. NY...FROST ADVISORY FROM 2 AM TO 10 AM EDT TUESDAY FOR NYZ067-068. NJ...FROST ADVISORY FROM 2 AM TO 10 AM EDT TUESDAY FOR NJZ002. MARINE...NONE. && $$ SYNOPSIS...BS NEAR TERM...MALOIT SHORT TERM...BS LONG TERM...BS AVIATION...MALOIT MARINE...BC/MALOIT HYDROLOGY...BS ct AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIAMI FL 945 AM EDT SUN OCT 5 2008 .UPDATE... NO CHANGE TO THE SHORT TERM OR LONG TERM FORECAST. FOR THE SHORT TERM...HAVE SCATTERED POPS OVER MOST OF THE CWA WITH MORE NUMEROUS ACTIVITY OVER THE NORTHERN THIRD OF THE SOUTH FLORIDA PENINSULA. THE DEW POINTS REMAIN ELEVATED ACROSS THE REGION...MID 70S AND ABOVE. IN ADDITION THE 12Z SOUNDING INDICATED PWATS JUST UNDER TWO INCHES...SUFFICIENT INSTABILITY TO SUPPORT SOME CONVECTION AND THERE IS SOME CLEARING OCCURRING OVER PORTIONS OF THE PENINSULA FOR DAY TIME HEATING TO TAKE EFFECT. MOST SHOWER AND THUNDERSTORM ACTIVITY IS EXPECTED DURING THE AFTERNOON AND EARLY EVENING...WITH A FEW STRONG THUNDERSTORMS POSSIBLE...WITH SMALL HAIL AND GUSTS TO NEAR 45 KNOTS POSSIBLE. 60 .PREVIOUS DISCUSSION... .AVIATION... WIDESPREAD MID/HIGH CLOUDS LINGER ACROSS SOUTH FL THIS MORNING WITH SOME SHOWERS NEAR KPBI. EASTERLY WINDS WILL INCREASE SOME BY MID MORNING WHICH WILL ALLOW AN EAST COAST SEA BREEZE TO COME INLAND AND IGNITE SHRA AND TSRA WITH IT. SW FLOW ALOFT MAY ALLOW ACTIVITY TO MOVE BACK TOWARDS THE COAST SLIGHTLY AS IT DEVELOPS ALONG SEA BREEZE SO WILL CARRY VCTS AT EAST COAST TERMINALS. OTHER SCT TSRA SHOULD DEVELOP NEAR KAPF BY MID DAY OR EARLY AFTERNOON. HEAVY RAINFALL LIKELY AGAIN TODAY...AND ANY SHRA/TSRA CAN BE ACCOMPANIED BY REDUCED CIGS/VSBYS...BUT TIMING AT ANY ONE TERMINAL IS HIGHLY QUESTIONABLE AT THIS HOUR AND WILL NOT CARRY A TEMPO GROUP AS A RESULT. /STRASSBERG && .PREV DISCUSSION... /ISSUED 341 AM EDT SUN OCT 5 2008/ SHORT TERM...TODAY AND TONIGHT...WEAK SFC FRONTAL BOUNDARY ACROSS MAINLAND S. FLORIDA ATTM WILL CONTINUE TO SLOWLY MOVE NORTHWEST TODAY. MOST RECENT RUC ANALYSIS SHOWS RATHER STRONG LOW LVL CONVERGENCE (850 MB) TO THE EAST OF THIS BOUNDARY, WHILE SIGNIFICANT DIV IS INDICATED ALOFT ASSOCIATED WITH THE SUBTROPICAL JET AROUND THE BASE OF A LONG WAVE MID LATITUDE TROUGH. THESE FEATURES ARE EXPECTED TO REMAIN IN THE VICINITY OF THE LOCAL AREA TODAY SO THE CHANCE OF PRECIP WILL REMAIN HIGH (ALTHOUGH THE FOCUS WILL PROBABLY BE OVR CENTRAL FLORIDA NEAR THE LOW LVL BOUNDARY) ESPECIALLY ACROSS NORTHERN PORTIONS OF MAINLAND SOUTH FLORIDA. CLOUD COVER TODAY WILL ALSO CONTRIBUTE TO KEEP MAX TEMPS ON THE COOL SIDE, SO DECIDED TO GO 3 TO 4 DEGREES BELOW GUIDANCE IN MOST AREAS. THE LOW LVL BOUNDARY IS EXPECTED TO BE WELL NORTH OF THE LOCAL AREA, AND THE UPPER TROUGH BE REPLACED BY DEEP LAYER RIDGE TONIGHT, LEADING TO A SIGNIFICANT IMPROVEMENT IN THE WX CONDS OVR MAINLAND S. FL. MONDAY THROUGH TUESDAY...A MID/UPR LVL RIDGE WILL REMAIN OVR THE PENINSULA WHILE A SFC RIDGE BUILDS SOUTH FROM THE MID ATLANTIC REGION. THIS WILL RESULT IN LESS CONVECTIVE ACTIVITY AND A RETURN TO MORE CLIMATOLOGICAL POPS. LONG TERM...WEDNESDAY THROUGH SATURDAY...THE LATEST GFS RUN SHOWS QUITE A DIFFERENT PICTURE THAN THE PREVIOUS RUN (24 HRS AGO). SHORT WAVE OVER THE FOUR CORNERS REGION TODAY WILL RAPIDLY MOVE EAST AND DEEPEN WITH A CLOSED 500 MB LOW MOVING FROM AK TO THE CAROLINAS WEDNESDAY THROUGH THURSDAY. SFC CYCLONE WILL DRAG A FRONT SEWRD WITH GFS BRINGING THE FRONT ACROSS CENTRAL FLORIDA THURSDAY NIGHT THROUGH FRIDAY. HOWEVER, NO MUCH PRECIP IS INDICATED WITH THIS SYSTEM. MARINE...MOSTLY EAST WINDS AT 15 KNOTS OR LESS WITH SEAS AT 4 FEET OR LESS SHOULD BE EXPECTED THROUGH THIS PERIOD. SFC WINDS MAY SHIFT TO MORE SE-S WEDNESDAY AND THURSDAY AS THE AFOREMENTIONED FRONT MOVES INTO N-CENTRAL FLORIDA. FIRE WEATHER...NO PROBLEMS AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 77 88 78 88 / 30 40 20 30 FORT LAUDERDALE 78 87 79 87 / 30 30 20 30 MIAMI 76 88 79 89 / 30 30 20 30 NAPLES 73 90 74 90 / 30 40 20 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ LONG TERM...47/RHG SHORT TERM/AVIATION...15/JR fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIAMI FL 731 AM EDT SUN OCT 5 2008 .AVIATION... WIDESPREAD MID/HIGH CLOUDS LINGER ACROSS SOUTH FL THIS MORNING WITH SOME SHOWERS NEAR KPBI. EASTERLY WINDS WILL INCREASE SOME BY MID MORNING WHICH WILL ALLOW AN EAST COAST SEA BREEZE TO COME INLAND AND IGNITE SHRA AND TSRA WITH IT. SW FLOW ALOFT MAY ALLOW ACTIVITY TO MOVE BACK TOWARDS THE COAST SLIGHTLY AS IT DEVELOPS ALONG SEA BREEZE SO WILL CARRY VCTS AT EAST COAST TERMINALS. OTHER SCT TSRA SHOULD DEVELOP NEAR KAPF BY MID DAY OR EARLY AFTERNOON. HEAVY RAINFALL LIKELY AGAIN TODAY...AND ANY SHRA/TSRA CAN BE ACCOMPANIED BY REDUCED CIGS/VSBYS...BUT TIMING AT ANY ONE TERMINAL IS HIGHLY QUESTIONABLE AT THIS HOUR AND WILL NOT CARRY A TEMPO GROUP AS A RESULT. /STRASSBERG && .PREV DISCUSSION... /ISSUED 341 AM EDT SUN OCT 5 2008/ SHORT TERM...TODAY AND TONIGHT...WEAK SFC FRONTAL BOUNDARY ACROSS MAINLAND S. FLORIDA ATTM WILL CONTINUE TO SLOWLY MOVE NORTHWEST TODAY. MOST RECENT RUC ANALYSIS SHOWS RATHER STRONG LOW LVL CONVERGENCE (850 MB) TO THE EAST OF THIS BOUNDARY, WHILE SIGNIFICANT DIV IS INDICATED ALOFT ASSOCIATED WITH THE SUBTROPICAL JET AROUND THE BASE OF A LONG WAVE MID LATITUDE TROUGH. THESE FEATURES ARE EXPECTED TO REMAIN IN THE VICINITY OF THE LOCAL AREA TODAY SO THE CHANCE OF PRECIP WILL REMAIN HIGH (ALTHOUGH THE FOCUS WILL PROBABLY BE OVR CENTRAL FLORIDA NEAR THE LOW LVL BOUNDARY) ESPECIALLY ACROSS NORTHERN PORTIONS OF MAINLAND SOUTH FLORIDA. CLOUD COVER TODAY WILL ALSO CONTRIBUTE TO KEEP MAX TEMPS ON THE COOL SIDE, SO DECIDED TO GO 3 TO 4 DEGREES BELOW GUIDANCE IN MOST AREAS. THE LOW LVL BOUNDARY IS EXPECTED TO BE WELL NORTH OF THE LOCAL AREA, AND THE UPPER TROUGH BE REPLACED BY DEEP LAYER RIDGE TONIGHT, LEADING TO A SIGNIFICANT IMPROVEMENT IN THE WX CONDS OVR MAINLAND S. FL. MONDAY THROUGH TUESDAY...A MID/UPR LVL RIDGE WILL REMAIN OVR THE PENINSULA WHILE A SFC RIDGE BUILDS SOUTH FROM THE MID ATLANTIC REGION. THIS WILL RESULT IN LESS CONVECTIVE ACTIVITY AND A RETURN TO MORE CLIMATOLOGICAL POPS. LONG TERM...WEDNESDAY THROUGH SATURDAY...THE LATEST GFS RUN SHOWS QUITE A DIFFERENT PICTURE THAN THE PREVIOUS RUN (24 HRS AGO). SHORT WAVE OVER THE FOUR CORNERS REGION TODAY WILL RAPIDLY MOVE EAST AND DEEPEN WITH A CLOSED 500 MB LOW MOVING FROM AK TO THE CAROLINAS WEDNESDAY THROUGH THURSDAY. SFC CYCLONE WILL DRAG A FRONT SEWRD WITH GFS BRINGING THE FRONT ACROSS CENTRAL FLORIDA THURSDAY NIGHT THROUGH FRIDAY. HOWEVER, NO MUCH PRECIP IS INDICATED WITH THIS SYSTEM. MARINE...MOSTLY EAST WINDS AT 15 KNOTS OR LESS WITH SEAS AT 4 FEET OR LESS SHOULD BE EXPECTED THROUGH THIS PERIOD. SFC WINDS MAY SHIFT TO MORE SE-S WEDNESDAY AND THURSDAY AS THE AFOREMENTIONED FRONT MOVES INTO N-CENTRAL FLORIDA. FIRE WEATHER...NO PROBLEMS AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 77 88 78 88 / 30 40 20 30 FORT LAUDERDALE 78 87 79 87 / 30 30 20 30 MIAMI 76 88 79 89 / 30 30 20 30 NAPLES 73 90 74 90 / 30 40 20 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ LONG TERM...47/RHG SHORT TERM/AVIATION...15/JR fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIAMI FL 341 AM EDT SUN OCT 5 2008 .SHORT TERM...TODAY AND TONIGHT...WEAK SFC FRONTAL BOUNDARY ACROSS MAINLAND S. FLORIDA ATTM WILL CONTINUE TO SLOWLY MOVE NORTHWEST TODAY. MOST RECENT RUC ANALYSIS SHOWS RATHER STRONG LOW LVL CONVERGENCE (850 MB) TO THE EAST OF THIS BOUNDARY, WHILE SIGNIFICANT DIV IS INDICATED ALOFT ASSOCIATED WITH THE SUBTROPICAL JET AROUND THE BASE OF A LONG WAVE MID LATITUDE TROUGH. THESE FEATURES ARE EXPECTED TO REMAIN IN THE VICINITY OF THE LOCAL AREA TODAY SO THE CHANCE OF PRECIP WILL REMAIN HIGH (ALTHOUGH THE FOCUS WILL PROBABLY BE OVR CENTRAL FLORIDA NEAR THE LOW LVL BOUNDARY) ESPECIALLY ACROSS NORTHERN PORTIONS OF MAINLAND SOUTH FLORIDA. CLOUD COVER TODAY WILL ALSO CONTRIBUTE TO KEEP MAX TEMPS ON THE COOL SIDE, SO DECIDED TO GO 3 TO 4 DEGREES BELOW GUIDANCE IN MOST AREAS. THE LOW LVL BOUNDARY IS EXPECTED TO BE WELL NORTH OF THE LOCAL AREA, AND THE UPPER TROUGH BE REPLACED BY DEEP LAYER RIDGE TONIGHT, LEADING TO A SIGNIFICANT IMPROVEMENT IN THE WX CONDS OVR MAINLAND S. FL. MONDAY THROUGH TUESDAY...A MID/UPR LVL RIDGE WILL REMAIN OVR THE PENINSULA WHILE A SFC RIDGE BUILDS SOUTH FROM THE MID ATLANTIC REGION. THIS WILL RESULT IN LESS CONVECTIVE ACTIVITY AND A RETURN TO MORE CLIMATOLOGICAL POPS. && .LONG TERM...WEDNESDAY THROUGH SATURDAY...THE LATEST GFS RUN SHOWS QUITE A DIFFERENT PICTURE THAN THE PREVIOUS RUN (24 HRS AGO). SHORT WAVE OVER THE FOUR CORNERS REGION TODAY WILL RAPIDLY MOVE EAST AND DEEPEN WITH A CLOSED 500 MB LOW MOVING FROM AK TO THE CAROLINAS WEDNESDAY THROUGH THURSDAY. SFC CYCLONE WILL DRAG A FRONT SEWRD WITH GFS BRINGING THE FRONT ACROSS CENTRAL FLORIDA THURSDAY NIGHT THROUGH FRIDAY. HOWEVER, NO MUCH PRECIP IS INDICATED WITH THIS SYSTEM. .MARINE...MOSTLY EAST WINDS AT 15 KNOTS OR LESS WITH SEAS AT 4 FEET OR LESS SHOULD BE EXPECTED THROUGH THIS PERIOD. SFC WINDS MAY SHIFT TO MORE SE-S WEDNESDAY AND THURSDAY AS THE AFOREMENTIONED FRONT MOVES INTO N-CENTRAL FLORIDA. && .FIRE WEATHER...NO PROBLEMS AT THIS TIME. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 83 77 88 78 / 60 30 40 20 FORT LAUDERDALE 83 78 87 79 / 60 30 30 20 MIAMI 83 76 88 79 / 60 30 30 20 NAPLES 83 73 90 74 / 60 30 40 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ SHORT TERM/LONG TERM/MARINE/FIRE...47/RGH AVIATION...15/JR fl AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL 639 PM CDT SUN OCT 5 2008 .DISCUSSION... 316 PM CDT THE SKY WILL SLOWLY CLEAR TONIGHT. THE NEXT CHANCE OF RAIN WILL BE TUESDAY THROUGH WEDNESDAY NIGHT. THE WARM FRONT WILL MOVE INTO NORTHERN ILLINOIS AND NORTHWEST INDIANA MONDAY AND MAY BECOME STATIONARY. THE PRECIPITATION ASSOCIATED WITH WEAK OVERRUNNING AIR WILL MOVE INTO WISCONSIN AND NORTHERN LAKE MICHIGAN TONIGHT. THE HIGH TEMPERATURE FOR MONDAY AND TUESDAY IS EXPECTED TO BE IN THE 70S...ESPECIALLY AWAY FROM LAKE MICHIGAN. WE USED THE OUR LOCAL WRF-ARW MODEL FOR THE FORECAST OF PRECIPITATION AND ISENTROPIC LIFT TONIGHT. FOR TUESDAY THROUGH THURSDAY...A LARGE 500 MB WAVE TROUGH WAS OVER THE WESTERN UNITED STATES AND CANADA THIS MORNING. THIS TROUGH IS FORECAST TO MOVE EAST INTO THE MISSISSIPPI VALLEY BY MONDAY EVENING. THIS 500 MB WAVE TROUGH WILL MOVE INTO ILLINOIS BY LATE TUESDAY NIGHT. THE ECMWF HAS A LONG MERIDIONAL SURFACE PRESSURE TROUGH FROM ONTARIO TO LOUISIANA BY WEDNESDAY MORNING. WE USED OUTPUT FROM THE ECMWF MODEL FOR GUIDANCE IN THIS FORECAST. THE PRECIPITATION IS EXPECTED TO BE ALONG THIS SURFACE TROUGH IN A NARROW BAND ABOUT 750 MILES WIDE OR FROM EASTERN OHIO TO WESTERN MISSOURI AT 12 UTC WEDNESDAY. MOST OF THIS PRECIPITATING WILL BE SHOWERS AND ISOLATED THUNDERSTORMS. THE RAIN WILL BE EAST OF OUR FORECAST AREA BY LATE THURSDAY NIGHT. WE EXPECT THE HIGH TEMPERATURES TO BE IN THE UPPER 60S TO AROUND 70 WEDNESDAY AND THURSDAY. FRIDAY THROUGH SUNDAY...WE EXPECT DRY CONDITIONS FRIDAY. THERE FORECAST A CHANCE OF SHOWERS SATURDAY AND SUNDAY. A SURFACE LOW WILL MOVE INTO MINNESOTA AND THAT LOW WILL DRAG A WARM FRONT ACROSS NORTHERN ILLINOIS AS IT MOVES NORTH. && .AVIATION... 0000 UTC TAFS...RELATIVELY QUIET WEATHER EXPECTED OVER THE NEXT 24 HOURS UNDER A 500MB RIDGE MOVING THROUGH AND FAIRLY DRY SOUTHEAST SURFACE FLOW. NAM/GFS AND ENSEMBLES ALL KEEP PRECIP TO OUR NORTH UNTIL SOMETIME ON TUESDAY WHEN A SURFACE TROUGH MOVES OUT OF THE PLAINS TOWARD OUR AREA. HAVE ELECTED TO GO WITH ONE LINE TAFS TO GIVE AN OVERALL SENSE OF WIND SPEED AND DIRECTION THROUGH THE PERIOD. 21Z RUC SHOWS WINDS TURNING MORE SOUTHEAST FOR A WHILE AFTER MIDNIGHT...BUT OVERALL DIRECTION IS EXPECTED TO BE JUST SOUTH OF EAST. WILL HAVE TO MONITOR NEW GUIDANCE LATER THIS EVENING AND SEE ABOUT INTRODUCING INCREASED WIND SPEEDS FOR TOMORROW AFTERNOON. LENNING && .MARINE... 201 PM CDT WITH A RIDGE OF HIGH PRESSURE SITTING ACROSS THE LAKES WINDS WILL SLOWLY VEER FROM THE EAST-SOUTHEAST TO THE SOUTH THROUGH THE EARLY PORTION OF THE WEEK. AS THE LOW PRESSURE SYSTEM OFF TO THE WEST TRACKS EASTWARD...THE PRESSURE GRADIENT IS EXPECTED TO TIGHTEN UP AND STRENGTHEN. WINDS WILL LIKELY APPROACH SMALL CRAFT ADVISORY LEVELS OVERNIGHT TONIGHT AND PUSHING 30KTS OUT OVER THE OPEN WATERS THROUGH TUESDAY. THE EXTENDED PORTION OF THE FORECAST PERIOD IS A BIT UNCERTAIN AT THIS POINT BUT SHOULD MAINLY BE IN LIGHT FLOW THROUGH THE END OF THE WEEK AFTER THE COLD FRONT COMES THROUGH ON WEDNESDAY. HALBACH && .LOT WATCHES/WARNINGS/ADVISORIES... IL...NONE. IN...NONE. LM...SMALL CRAFT ADVISORY...LMZ740-LMZ741-LMZ742...10 PM SUNDAY TO 4 PM TUESDAY. && $$ il AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 145 AM EDT MON OCT 6 2008 .AVIATION... LIGHT SHOWERS LINGERING OVER LAKE MI MOVING SE SHOWING WEAKENING TREND AND SHOULD NOT IMPACT KSBN BEYOND SPRINKLES WITH VFR CONDITIONS CONTINUING. VFR BKN CEILINGS GRADUALLY THIN TODAY WITH BREEZY E TO SE WINDS THIS AFTERNOON. && PREV DISCUSSION... /ISSUED 340 PM EDT SUN OCT 5 2008/ SHORT TERM... TONIGHT THROUGH MONDAY NIGHT WEAK REGION OF LIFT ALOFT ASSOCIATED WITH MID LEVEL RETURN FLOW UNDER INCREASING LARGE SCALE SCENT PER AN ADVANCING UPPER TROUGH OVER THE GREAT LAKES...CONTINUES TO SUPPORT LIGHT RAIN OVER WI/IL/AND NOW NW IN. ACTIVITY CONTINUES TO ERODE ON THE SOUTHERN END OF THE RAIN SHIELD WITH THE BEST FORCING AND LIFT STILL NORTH OF THE REGION. HOWEVER...RECENT RADAR RETURNS INDICATE EXPANSION OF THE RAIN SHIELD OVER LK MI...AN INDICATION THAT BETTER FORCING PER THE ADVANCING MID LEVEL WAVE MAY BE ARRIVING SOONER THAN PREVIOUSLY PROGGED IN FORECAST MODELS. THE ORIGINAL EXPECTATION WAS FOR RAIN TO WAIN THIS AFTERNOON AS IT PUSHES EAST AWAY FROM LL VEERED SOUTHERLY FLOW/BEST MOISTURE TRANSPORT AND THEN REDEVELOP LATER AS THE PROGGED UPPER VORT SHIFTS SE INTO THE EASTERN GREAT LAKES. NOW IT SEEMS THAT THIS MAY OCCUR EARLIER AS INDICATED BY RECENT TRENDS IN OBS. HENCE HAVE RAISE POPS NW THIS AFTERNOON...AND SHIFTED SOUTH AND RAISED POPS TONIGHT. RATHER DECENT LARGE SCALE ASCENT WILL BE IN PLACE TONIGHT AS AN AREA OF UPPER LEVEL CONVERGENCE LOOKS TO SETUP OVER THE NORTHERN PORTION OF THE FA AND REMAIN QUASI- STATIONARY THROUGH MUCH OF MONDAY. H5 FLOW ANALYSIS CONFIRMS DECENT MID LEVEL CONVERGENCE WITH CONTINUED LIFT IN PLACE PROGGED BY ISENTROPIC ANALYSIS ON THE 295-300K SURFACES. THIS SEMI-BLOCK IN THE PROGRESSION OF UPPER LEVEL WAVES IS THE RESULT OF RIDGING TO THE WEST OF FA WITH HEIGHT FALLS BEHIND THE DEPARTING NE CONUS TROUGH. THIS WILL HAVE MAJOR RAMIFICATIONS ON THE FORECAST THE NEXT 24 HOURS AS RAIN CHANCES LOOK ELEVATED IN THE NE TONIGHT...WITH TEMPS/AND CLOUDS HIGHLY AFFECTED MONDAY IN THE NE. INCREASED CLOUDS PER LINGERING MID LEVEL ASCENT WILL LOOK TO HIGHLY SUBDUE TEMPS IN THE NE. HAVE UTILIZED THE THE NAM12/GFS/UKMET AND RUC13 FOR FORECAST DETAILS...REMAINING CLOSE TO THE NAM12 WRT TO THE EVOLUTION OF HIGH TEMPS MON. CHANGES TO THE FORECAST PACKAGE INCLUDE THE AFOREMENTIONED POP ADJUSTMENT TONIGHT AND SKY AND TEMP CHANGES MONDAY. GIVEN MOSTLY CLEAR CONDITIONS OVER THE SW THIRD OF THE FA MON/DEEP MIXING EXPECTED AS OBSERVED TODAY IN IL WHERE HIGHS ARE IN THE 80S/AND H85 TEMPS AROUND 14 C...HAVE RAISED HIGHS IN THE SW TO ACCOUNT FOR THIS. HAVE LOWERED TEMPS IN THE NE SOME TO REFLECT PERSISTENT CLOUD COVER EXPECTED THROUGH THE MAJORITY OF THE AFTERNOON. OTHERWISE...RIDGING LOOKS TO FINALLY OVERTAKE THE ENTIRE FA BY LATE AFTERNOON...AND ALLOW CLEARING ACROSS THE BOARD. LONG TERM... AS HAS BEEN ECHOED IN THE LAST SEVERAL DISCUSSION...HUGE DIFFERENCES CONTINUE IN THE HANDLING OF THE EVOLUTION AND EVENTUAL LOCATION/EFFECT OF THE TROUGH IN THE WEST. MORE SPECIFIC DETAILS CAN BE FOUND ON TRENDS AND ISSUES IN EXTENDED DISCUSSIONS FROM HPC. MAIN FOCUS FOR THE LONG TERM WILL BE THE TUESDAY THROUGH THURSDAY TIME FRAME. ABOUT THE ONLY THING THAT CAN BE SAID WITH CERTAINTY IN THE FOCUS TIME FRAME IS THAT TUESDAY AND TUESDAY EVENING WILL BE DRY AS RIDGE WILL HOLD ON JUST A BIT LONGER AS IT FINALLY BEGINS TO SHIFT EAST SOMEWHAT. HOWEVER IT IS THE HOLDING OF THIS RIDGE AND A SERIES OF UPSTREAM SYSTEM THAT WILL CARVE OUT THE TROUGH THAT HAS BEEN SO PROBLEMATIC OF LATE. GFS CONTINUES TO EJECT THE UPPER LOW AND TROUGH RATHER QUICKLY WITH CHANCES FOR RAIN ARRIVING BY LATE TUESDAY NIGHT AND ENDING BY LATE WEDNESDAY NIGHT. AS NOTED IN THE OVERNIGHT DISCUSSION...GFS IS SUFFERING SOME CONVECTIVE FEEDBACK ISSUES THAT MAKES IT HARDER TO SWALLOW AS WELL. THE NAM ALSO APPEARS TO BE SUFFERING SOMEWHAT FROM FEEDBACK ISSUES. BULK OF THE PRECIPITATION BEING HELD SE OF THE FORECAST AREA. THE ECMWF...WHICH OVERALL HAS BEEN A BIT MORE RELIABLE IN PAST WEEKS IS ALSO HAVING SOME ISSUES WITH THE HANDLING OF THE SETUP. GFS ENSEMBLE STANDARD DEVIATIONS FROM LAST NIGHT FOR THIS TIME FRAME AT A WHOPPING 18 TO 20...MAKING IT EVEN MORE DIFFICULT TO SORT OUT DETAILS. THE ONLY THING THAT CAN BE DONE AT THIS POINT IS WAIT IT OUT AND SEE IF ANY OF THE MODELS CAN COME AROUND AND START HONING IN ON THINGS. AS A RESULT...ONLY MINOR CHANGES MADE MAINLY IN SKY COVER THROUGH THURSDAY. OBVIOUSLY TO MAKE ANY CHANGES TO THE LONG TERM BEYOND THURSDAY WOULD BE GROSSLY PREMATURE AT THIS POINT. TRENDS WOULD SUGGEST THAT THE PERIOD WILL BE DRY WHICH IS WHAT THE GRIDS WILL REFLECT THROUGH SUNDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...FISHER AVIATION...LUDINGTON in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 716 PM EDT SUN OCT 5 2008 .AVIATION... SHOWERS MOVG THROUGH NRN INDIANA WKNG AS THEY MOVE EAST OF MID LEVEL RIDGE WITH RESULTANT WKNG THETA-E ADVECTION. HWVR...WITH RIDGE MOVG ONLY VERY SLOWLY EAST OVERNIGHT...EXPECT MID CLOUDS WILL LINGER AT THE TERMINALS INTO MONDAY...PSBLY DIMINISHING LATE IN THE PD. SFC HIGH OVER NE ONTARIO WILL MOVE SE BEHIND SHRTWV ROTATING THROUGH THE LWR GRTLKS TNGT/MON RESULTING IN INCRSG ELY PRES GRADIENT TOMORROW WHICH ALONG WITH DIURNAL MIXING SHOULD RESULT IN 12-16KT ELY SFC WINDS. DRY LOW LEVEL ELY FLOW COMBINED WITH LINGERING MID CLOUDS LIMITING HEATING SHOULD PREVENT ANY CU FROM FORMING DURING THE DAY MONDAY. && .PREV DISCUSSION... /ISSUED 340 PM EDT SUN OCT 5 2008/ SHORT TERM... TONIGHT THROUGH MONDAY NIGHT WEAK REGION OF LIFT ALOFT ASSOCIATED WITH MID LEVEL RETURN FLOW UNDER INCREASING LARGE SCALE SCENT PER AN ADVANCING UPPER TROUGH OVER THE GREAT LAKES...CONTINUES TO SUPPORT LIGHT RAIN OVER WI/IL/AND NOW NW IN. ACTIVITY CONTINUES TO ERODE ON THE SOUTHERN END OF THE RAIN SHIELD WITH THE BEST FORCING AND LIFT STILL NORTH OF THE REGION. HOWEVER...RECENT RADAR RETURNS INDICATE EXPANSION OF THE RAIN SHIELD OVER LK MI...AN INDICATION THAT BETTER FORCING PER THE ADVANCING MID LEVEL WAVE MAY BE ARRIVING SOONER THAN PREVIOUSLY PROGGED IN FORECAST MODELS. THE ORIGINAL EXPECTATION WAS FOR RAIN TO WAIN THIS AFTERNOON AS IT PUSHES EAST AWAY FROM LL VEERED SOUTHERLY FLOW/BEST MOISTURE TRANSPORT AND THEN REDEVELOP LATER AS THE PROGGED UPPER VORT SHIFTS SE INTO THE EASTERN GREAT LAKES. NOW IT SEEMS THAT THIS MAY OCCUR EARLIER AS INDICATED BY RECENT TRENDS IN OBS. HENCE HAVE RAISE POPS NW THIS AFTERNOON...AND SHIFTED SOUTH AND RAISED POPS TONIGHT. RATHER DECENT LARGE SCALE ASCENT WILL BE IN PLACE TONIGHT AS AN AREA OF UPPER LEVEL CONVERGENCE LOOKS TO SETUP OVER THE NORTHERN PORTION OF THE FA AND REMAIN QUASI- STATIONARY THROUGH MUCH OF MONDAY. H5 FLOW ANALYSIS CONFIRMS DECENT MID LEVEL CONVERGENCE WITH CONTINUED LIFT IN PLACE PROGGED BY ISENTROPIC ANALYSIS ON THE 295-300K SURFACES. THIS SEMI-BLOCK IN THE PROGRESSION OF UPPER LEVEL WAVES IS THE RESULT OF RIDGING TO THE WEST OF FA WITH HEIGHT FALLS BEHIND THE DEPARTING NE CONUS TROUGH. THIS WILL HAVE MAJOR RAMIFICATIONS ON THE FORECAST THE NEXT 24 HOURS AS RAIN CHANCES LOOK ELEVATED IN THE NE TONIGHT...WITH TEMPS/AND CLOUDS HIGHLY AFFECTED MONDAY IN THE NE. INCREASED CLOUDS PER LINGERING MID LEVEL ASCENT WILL LOOK TO HIGHLY SUBDUE TEMPS IN THE NE. HAVE UTILIZED THE THE NAM12/GFS/UKMET AND RUC13 FOR FORECAST DETAILS...REMAINING CLOSE TO THE NAM12 WRT TO THE EVOLUTION OF HIGH TEMPS MON. CHANGES TO THE FORECAST PACKAGE INCLUDE THE AFOREMENTIONED POP ADJUSTMENT TONIGHT AND SKY AND TEMP CHANGES MONDAY. GIVEN MOSTLY CLEAR CONDITIONS OVER THE SW THIRD OF THE FA MON/DEEP MIXING EXPECTED AS OBSERVED TODAY IN IL WHERE HIGHS ARE IN THE 80S/AND H85 TEMPS AROUND 14 C...HAVE RAISED HIGHS IN THE SW TO ACCOUNT FOR THIS. HAVE LOWERED TEMPS IN THE NE SOME TO REFLECT PERSISTENT CLOUD COVER EXPECTED THROUGH THE MAJORITY OF THE AFTERNOON. OTHERWISE...RIDGING LOOKS TO FINALLY OVERTAKE THE ENTIRE FA BY LATE AFTERNOON...AND ALLOW CLEARING ACROSS THE BOARD. LONG TERM... AS HAS BEEN ECHOED IN THE LAST SEVERAL DISCUSSION...HUGE DIFFERENCES CONTINUE IN THE HANDLING OF THE EVOLUTION AND EVENTUAL LOCATION/EFFECT OF THE TROUGH IN THE WEST. MORE SPECIFIC DETAILS CAN BE FOUND ON TRENDS AND ISSUES IN EXTENDED DISCUSSIONS FROM HPC. MAIN FOCUS FOR THE LONG TERM WILL BE THE TUESDAY THROUGH THURSDAY TIME FRAME. ABOUT THE ONLY THING THAT CAN BE SAID WITH CERTAINTY IN THE FOCUS TIME FRAME IS THAT TUESDAY AND TUESDAY EVENING WILL BE DRY AS RIDGE WILL HOLD ON JUST A BIT LONGER AS IT FINALLY BEGINS TO SHIFT EAST SOMEWHAT. HOWEVER IT IS THE HOLDING OF THIS RIDGE AND A SERIES OF UPSTREAM SYSTEM THAT WILL CARVE OUT THE TROUGH THAT HAS BEEN SO PROBLEMATIC OF LATE. GFS CONTINUES TO EJECT THE UPPER LOW AND TROUGH RATHER QUICKLY WITH CHANCES FOR RAIN ARRIVING BY LATE TUESDAY NIGHT AND ENDING BY LATE WEDNESDAY NIGHT. AS NOTED IN THE OVERNIGHT DISCUSSION...GFS IS SUFFERING SOME CONVECTIVE FEEDBACK ISSUES THAT MAKES IT HARDER TO SWALLOW AS WELL. THE NAM ALSO APPEARS TO BE SUFFERING SOMEWHAT FROM FEEDBACK ISSUES. BULK OF THE PRECIPITATION BEING HELD SE OF THE FORECAST AREA. THE ECMWF...WHICH OVERALL HAS BEEN A BIT MORE RELIABLE IN PAST WEEKS IS ALSO HAVING SOME ISSUES WITH THE HANDLING OF THE SETUP. GFS ENSEMBLE STANDARD DEVIATIONS FROM LAST NIGHT FOR THIS TIME FRAME AT A WHOPPING 18 TO 20...MAKING IT EVEN MORE DIFFICULT TO SORT OUT DETAILS. THE ONLY THING THAT CAN BE DONE AT THIS POINT IS WAIT IT OUT AND SEE IF ANY OF THE MODELS CAN COME AROUND AND START HONING IN ON THINGS. AS A RESULT...ONLY MINOR CHANGES MADE MAINLY IN SKY COVER THROUGH THURSDAY. OBVIOUSLY TO MAKE ANY CHANGES TO THE LONG TERM BEYOND THURSDAY WOULD BE GROSSLY PREMATURE AT THIS POINT. TRENDS WOULD SUGGEST THAT THE PERIOD WILL BE DRY WHICH IS WHAT THE GRIDS WILL REFLECT THROUGH SUNDAY. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...FISHER AVIATION...JT in AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORTHERN INDIANA 340 PM EDT SUN OCT 5 2008 .SHORT TERM... TONIGHT THROUGH MONDAY NIGHT WEAK REGION OF LIFT ALOFT ASSOCIATED WITH MID LEVEL RETURN FLOW UNDER INCREASING LARGE SCALE SCENT PER AN ADVANCING UPPER TROUGH OVER THE GREAT LAKES...CONTINUES TO SUPPORT LIGHT RAIN OVER WI/IL/AND NOW NW IN. ACTIVITY CONTINUES TO ERODE ON THE SOUTHERN END OF THE RAIN SHIELD WITH THE BEST FORCING AND LIFT STILL NORTH OF THE REGION. HOWEVER...RECENT RADAR RETURNS INDICATE EXPANSION OF THE RAIN SHIELD OVER LK MI...AN INDICATION THAT BETTER FORCING PER THE ADVANCING MID LEVEL WAVE MAY BE ARRIVING SOONER THAN PREVIOUSLY PROGGED IN FORECAST MODELS. THE ORIGINAL EXPECTATION WAS FOR RAIN TO WAIN THIS AFTERNOON AS IT PUSHES EAST AWAY FROM LL VEERED SOUTHERLY FLOW/BEST MOISTURE TRANSPORT AND THEN REDEVELOP LATER AS THE PROGGED UPPER VORT SHIFTS SE INTO THE EASTERN GREAT LAKES. NOW IT SEEMS THAT THIS MAY OCCUR EARLIER AS INDICATED BY RECENT TRENDS IN OBS. HENCE HAVE RAISE POPS NW THIS AFTERNOON...AND SHIFTED SOUTH AND RAISED POPS TONIGHT. RATHER DECENT LARGE SCALE ASCENT WILL BE IN PLACE TONIGHT AS AN AREA OF UPPER LEVEL CONVERGENCE LOOKS TO SETUP OVER THE NORTHERN PORTION OF THE FA AND REMAIN QUASI- STATIONARY THROUGH MUCH OF MONDAY. H5 FLOW ANALYSIS CONFIRMS DECENT MID LEVEL CONVERGENCE WITH CONTINUED LIFT IN PLACE PROGGED BY ISENTROPIC ANALYSIS ON THE 295-300K SURFACES. THIS SEMI-BLOCK IN THE PROGRESSION OF UPPER LEVEL WAVES IS THE RESULT OF RIDGING TO THE WEST OF FA WITH HEIGHT FALLS BEHIND THE DEPARTING NE CONUS TROUGH. THIS WILL HAVE MAJOR RAMIFICATIONS ON THE FORECAST THE NEXT 24 HOURS AS RAIN CHANCES LOOK ELEVATED IN THE NE TONIGHT...WITH TEMPS/AND CLOUDS HIGHLY AFFECTED MONDAY IN THE NE. INCREASED CLOUDS PER LINGERING MID LEVEL ASCENT WILL LOOK TO HIGHLY SUBDUE TEMPS IN THE NE. HAVE UTILIZED THE THE NAM12/GFS/UKMET AND RUC13 FOR FORECAST DETAILS...REMAINING CLOSE TO THE NAM12 WRT TO THE EVOLUTION OF HIGH TEMPS MON. CHANGES TO THE FORECAST PACKAGE INCLUDE THE AFOREMENTIONED POP ADJUSTMENT TONIGHT AND SKY AND TEMP CHANGES MONDAY. GIVEN MOSTLY CLEAR CONDITIONS OVER THE SW THIRD OF THE FA MON/DEEP MIXING EXPECTED AS OBSERVED TODAY IN IL WHERE HIGHS ARE IN THE 80S/AND H85 TEMPS AROUND 14 C...HAVE RAISED HIGHS IN THE SW TO ACCOUNT FOR THIS. HAVE LOWERED TEMPS IN THE NE SOME TO REFLECT PERSISTENT CLOUD COVER EXPECTED THROUGH THE MAJORITY OF THE AFTERNOON. OTHERWISE...RIDGING LOOKS TO FINALLY OVERTAKE THE ENTIRE FA BY LATE AFTERNOON...AND ALLOW CLEARING ACROSS THE BOARD. && .LONG TERM... AS HAS BEEN ECHOED IN THE LAST SEVERAL DISCUSSION...HUGE DIFFERENCES CONTINUE IN THE HANDLING OF THE EVOLUTION AND EVENTUAL LOCATION/EFFECT OF THE TROUGH IN THE WEST. MORE SPECIFIC DETAILS CAN BE FOUND ON TRENDS AND ISSUES IN EXTENDED DISCUSSIONS FROM HPC. MAIN FOCUS FOR THE LONG TERM WILL BE THE TUESDAY THROUGH THURSDAY TIME FRAME. ABOUT THE ONLY THING THAT CAN BE SAID WITH CERTAINTY IN THE FOCUS TIME FRAME IS THAT TUESDAY AND TUESDAY EVENING WILL BE DRY AS RIDGE WILL HOLD ON JUST A BIT LONGER AS IT FINALLY BEGINS TO SHIFT EAST SOMEWHAT. HOWEVER IT IS THE HOLDING OF THIS RIDGE AND A SERIES OF UPSTREAM SYSTEM THAT WILL CARVE OUT THE TROUGH THAT HAS BEEN SO PROBLEMATIC OF LATE. GFS CONTINUES TO EJECT THE UPPER LOW AND TROUGH RATHER QUICKLY WITH CHANCES FOR RAIN ARRIVING BY LATE TUESDAY NIGHT AND ENDING BY LATE WEDNESDAY NIGHT. AS NOTED IN THE OVERNIGHT DISCUSSION...GFS IS SUFFERING SOME CONVECTIVE FEEDBACK ISSUES THAT MAKES IT HARDER TO SWALLOW AS WELL. THE NAM ALSO APPEARS TO BE SUFFERING SOMEWHAT FROM FEEDBACK ISSUES. BULK OF THE PRECIPITATION BEING HELD SE OF THE FORECAST AREA. THE ECMWF...WHICH OVERALL HAS BEEN A BIT MORE RELIABLE IN PAST WEEKS IS ALSO HAVING SOME ISSUES WITH THE HANDLING OF THE SETUP. GFS ENSEMBLE STANDARD DEVIATIONS FROM LAST NIGHT FOR THIS TIME FRAME AT A WHOPPING 18 TO 20...MAKING IT EVEN MORE DIFFICULT TO SORT OUT DETAILS. THE ONLY THING THAT CAN BE DONE AT THIS POINT IS WAIT IT OUT AND SEE IF ANY OF THE MODELS CAN COME AROUND AND START HONING IN ON THINGS. AS A RESULT...ONLY MINOR CHANGES MADE MAINLY IN SKY COVER THROUGH THURSDAY. OBVIOUSLY TO MAKE ANY CHANGES TO THE LONG TERM BEYOND THURSDAY WOULD BE GROSSLY PREMATURE AT THIS POINT. TRENDS WOULD SUGGEST THAT THE PERIOD WILL BE DRY WHICH IS WHAT THE GRIDS WILL REFLECT THROUGH SUNDAY. && .AVIATION.../18Z TAFS/ VFR CONDITIONS EXPECTED THROUGH THE PERIOD. WEAK ASCENT ASSOCIATED WITH VEERED LL FLOW PER DEVELOPING LOW PRESSURE IN THE PLAIN STATES AND INCREASED LARGE SCALE ASCENT FROM ANOTHER UPPER VORT MAX DIVING SE OUT OF ONTARIO...WILL CONTINUE TO SUPPORT SH ACTIVITY TO THE WEST AND NORTH OF THE FA. MID-LEVEL FLOW WOULD DIRECT ACTIVITY INTO THE AREA. HOWEVER...BEST FORCING AND FLOW WILL SHIFTS NORTH OF THE FA ONLY LEAVING A FEW DEBRIS MID AND HIGH LEVEL CLOUDS TO CONTEND WITH LOCALLY. FAR NW PORTIONS OF THE FA MAY SEE A BRIEF SHOWER/SPRINKLE THIS AFTERNOON...BUT NO FLIGHT RESTRICTIONS EXPECTED. MID/HIGHS CLOUDS WILL EXPAND EAST AND NORTH THROUGH THE DAY AND INTO TONIGHT. ADVANCING SECONDARY TROUGH NOW PUSHING INTO THE EASTERN GREAT LAKES WILL SUPPORT ANOTHER ROUND OF MID LEVEL CONVERGENCE OVER WI/MI AND EXTREME NORTHERN IN...SUPPORTING MID AND HIGH CLOUDINESS THROUGH THE NIGHT THERE AS H5 HEIGHTS REMAIN NEARLY FIXED LOCALLY PER AN ADVANCING RIDGE. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...NONE. MI...NONE. OH...NONE. LM...NONE. && $$ SHORT TERM...CHAMBERLAIN LONG TERM...FISHER AVIATION...CHAMBERLAIN in AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE DES MOINES IA 1158 AM CDT SUN OCT 5 2008 .SHORT TERM.../TODAY/ BIG QUESTION TODAY WILL BE PRECIP TRENDS...ESPECIALLY THIS MORNING. SEVERAL SHORT WAVES CONTINUE TO EJECT OUT OF WRN CONUS MEAN TROUGH INCLUDING ONE NOTED OVER ERN SD AND ITS ASSOCIATED NW-SE VORT LOBE. MUCH OF THE FORCING APPEARS TO BE THERMODYNAMIC WITH MODERATE/STRONG THETA-E ADVECTION AND FRONTOGENETICAL FORCING. ALTHOUGH QPF A BIT HOT FOR THE TIME BEING...MODELS GENERALLY SEEM TO BE HANDLING THIS WELL AS DEPICTED IN 300-310K ISENT LAYER WITH INCREASING UVM AND CONVERGENCE. SENSIBLE WX TRENDS SHOULD BE TO EXTENT CURRENT SD-NWRN IA BAND OF PRECIP SEWD ACROSS NERN IA AS REFLECTED IN MOST MODELS INCLUDING 4KM SPC/5KM ARX WRF RUNS. EXTRAPOLATION KEEPS BACK EDGE OVER NERN FORECAST AREA BY 12Z SO HAVE RAISED POPS WELL INTO CATEGORICAL IN THOSE SECTIONS. AS THE BAND OF 300-310K ISENT UVM LIFTS AWAY...PRECIP CHANCES SHOULD DECREASE AS MO VALLEY WARM FRONT LIFTS NWD BRING IA MORE INTO THE WARM SECTOR RELEGATING AFTERNOON POPS ONLY TO NRN PORTIONS. RAISED HIGHS A DEGREE OR SO IN MOST AREAS BASED ON NAM/RUC SOUNDINGS AND SREF SUGGESTIONS. GFS RAW TEMPS SOMEWHAT COOLER...CLOSER TO PERSISTENCE...BUT THIS DOES NOT SEEM LIKELY BASED ON STRENGTH OF WARM ADVECTION. .LONG TERM.../TONIGHT...SATURDAY/ THE SHORT RANGE CONTINUES TO BE WELL FORECAST. AFTER THE INITIAL SURGE OF MOISTURE TODAY...GFS/NAM BOTH SHOW QUIET PERIOD THROUGH MONDAY AFTERNOON WITH NEXT UPSTREAM WAVE AND MAIN UPPER LEVEL SYSTEM TRACKING NORTHEAST BY MONDAY NIGHT. WITH H850 LOW JUST TO WEST OF AREA BY MONDAY NIGHT...MOISTURE TRANSPORT AIMED RIGHT AT THE FORECAST AREA. LOW LVL JET INCREASES TO 30 TO 40KTS WITH MODEST QVECTOR CONVERGENCE OVER NORTHERN SECTIONS BY 12Z TUES WHICH CONTINUES MOST OF THE DAY...THOUGH WEAKER ACROSS THE FORECAST AREA. WITH SUPPORT OF CLOSED H850 LOW...WILL CONTINUE TO GO HIGH LIKELY...LOW CAT POPS WITH GREAT LIKELIHOOD OF RAIN/ISO THUNDER. PROFILES QUITE MOIST FOR TUESDAY WITH SATURATION THROUGH H300 THROUGH 18Z. WILL PWATS CONTINUE IN THE 1 TO 1.5 IN RANGE. INSTABILITY STILL LACKING TO ANY DEGREE FOR THE NEXT FEW DAYS...SO RUMBLES OF THUNDER AT MOST EXPECTED WITH LITTLE THREAT FOR ANY SEVERE. GEM/NAM/GFS AND 00Z EURO HAVE SYSTEM EXITING ON WED...ABOUT 12 HOURS SLOWER THAN PREVIOUS FCST. THOUGH BEST OF THE LIFT IS ALREADY EAST OF THE AREA...SOME CLOUDS AND LIGHT SHOWERS WILL CONTINUE FOR THE EAST. IN THE EXTENDED...PERIOD STILL LOOKS VERY ACTIVE WITH STRONG SYSTEM SWINGING ACROSS THE CENTRAL PLAINS BY DAYS 6 AND 7. MODELS HANDLING THE SYSTEM QUITE DIFFERENTLY AFTER AN INITIAL PUSH OF WARM AIR ADVECTION AND PRECIP ON FRIDAY. SOME WAA SHOWERS/ISO THUNDER FRI WITH A MILD DAY OR TWO BEFORE STRONG COLD FRONT ARRIVES. THOUGH BEYOND THE CURRENT PACKAGE...WILL BE INTERESTING TO SEE THE CHANGES UNFOLD. && .AVIATION...05/18Z SURFACE WARM FRONT ACROSS CENTRAL IOWA WILL CONTINUE MOVING SLOWLY NORTHEAST...BUT ANY SIGNIFICANT THREAT FOR SHRA/TSRA HAS MOVED NORTH OF THE AREA. VFR CONDITIONS BUT WITH PLENTY OF MID/HIGH CLOUDINESS ARE EXPECTED THROUGH THE TAF PERIOD. THERE IS AN OUTSIDE CHANCE OF ISOLATED LATE IN THE PERIOD AT KFOD AND KMCW...BUT NOT CONFIDENT ENOUGH TO MENTION AT THIS TIME. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...REV/BSS AVIATION...MOYER ia AREA FORECAST DISCUSSION...UPDATED AVIATION SECTION NATIONAL WEATHER SERVICE MARQUETTE MI 841 PM EDT MON OCT 6 2008 .SYNOPSIS... 19Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED AN INTENSE LOOKING TROUGH OFF THE COAST OF BRITISH COLUMBIA...WEAK RIDGING DEVELOPING DOWNSTREAM OVER THE PACIFIC NW...A TROUGH STRETCHING FROM ALBERTA/SASKATCHEWAN SOUTHEAST INTO THE CENTRAL PLAINS...AND RIDGING FROM THE OHIO VALLEY NORTHWARD ACROSS UPPER MI INTO NRN ONTARIO. DESPITE SUBSIDENCE UNDER THE UPPER RIDGE OVER UPPER MI...ALONG WITH A DRY SE FLOW COMING OUT OF HIGH PRESSURE IN EASTERN ONTARIO AS INDICATED BY THE 12Z APX SOUNDING (40C OR GREATER DEWPOINT DEPRESSIONS FROM 800MB UP TO 350MB)...WARM ADVECTION CLOUDS AND PCPN HAS MANAGED TO MOVE FROM NRN WI INTO THE WESTERN HALF OF THE CWA. IT SHOULD BE NOTED THAT THE PCPN IS FALLING APART...LIKELY DUE TO THE UPPER RIDGE STILL BUILDING AHEAD OF THE TROUGH AND THE INFLUENCE OF THE DRY AIR. IN ADDITION...PCPN REPORTS FROM AUTOMATED SITES IN UPPER MI HAVE ONLY BEEN AROUND 0.01. SOME BREAK UP OF THE CLOUDS EXISTS OVER SRN PORTIONS OF MN AND WI. HOWEVER...A MORE SUBSTANTIAL AREA OF PCPN EXISTS ALONG THE RED RIVER BTWN ND AND MN...IN AN AREA OF DPVA IMMEDIATELY AHEAD OF THE UPPER TROUGH AND IN AN AXIS OF PRECIPITABLE WATER AROUND 1.3 INCHES. DEWPOINTS REFLECT THE MORE MOIST AIRMASS AS WELL...WITH READINGS IN THE 50S OVER WI AND MN...WITH EVEN A FEW LOW 60S AS WELL...SOMEWHAT HUMID FOR THIS TIME OF THE YEAR. && .SHORT TERM (TONIGHT AND TUE)... LIGHT RAIN/SPRINKLES OVER THE CWA WILL DISSIPATE THIS EVENING... PROBABLY BEFORE 00Z...AS SUBSIDENCE AND RIDGING CONTINUES TO BUILD OVER THE CWA AHEAD OF THE TROUGH OVER THE WESTERN HIGH PLAINS INCHING CLOSER. THE REST OF THE NIGHT LOOKS DRY...WITH PERSISTENT DRY SE FLOW OUT OF THE HIGH PRESSURE AREA DRIFTING OFF TO THE EAST...AND RIDGING ALOFT. THEREFORE TONIGHTS ONLY ISSUES ARE CLOUDS AND TEMPS. CLOUD COVER CURRENTLY OVER THE WESTERN HALF OF THE CWA ASSOCIATED WITH WARM ADVECTION/MID-LEVEL FRONTOGENESIS SHOULD SLOWLY PUSH TO THE NORTHEAST WITH TIME. MEANWHILE...LOCATIONS NEAR THE WI BORDER SHOULD PARTIALLY CLEAR OUT. THEREFORE...A FULL CLOUD DECK IS NOT EXPECTED ACROSS ANY OF THE CWA TONIGHT...WHICH SHOULD ALLOW FOR SOME RADIATIONAL COOLING. HOWEVER...WITH A SE BREEZE GOING AND PRECIPITABLE WATER INCREASING WITH TIME TO BTWN 0.75 AND 1 INCH...TEMPS SHOULD NOT DROP TOO MUCH. ONLY CHANGE WAS TO THE PREVIOUS FORECAST WAS TO LOWER THEM A LITTLE IN THE INLAND AREAS OF THE EASTERN U.P. WITH MOSTLY CLEAR SKIES EARLY. ON TUE...THE ATTENTION IS FOCUSED TO THE BAND OF SHOWERS ALONG THE RED RIVER. MODELS ARE IN GOOD AGREEMENT ON A SLOWER MOTION COMPARED TO THE PREVIOUS FORECAST...LIKELY DUE TO THE STRONG UPPER AND SFC RIDGING DOWNSTREAM. DPVA ASSOCIATED WITH THE UPPER TROUGH SHIFTS EAST INTO THE WESTERN HALF OF THE CWA BTWN 18Z TUE AND 00Z WED. WITH AMPLE MOISTURE MOVING IN (PRECIPITABLE WATER CLIMBING TO OVER AN INCH)...THE DPVA SHOULD BE ENOUGH TO AT LEAST TRANSLATE THE CURRENT SHOWERS ALONG THE RED RIVER EASTWARD...REACHING FAR WESTERN LAKE SUPERIOR IN THE MORNING...THEN INTO THE FAR WESTERN U.P. IN THE AFTERNOON. RAISED POPS TO LIKELY OR CATEGORICAL IN THIS AREA. FOR THE CENTRAL U.P....DELAYED PCPN UNTIL LATE IN THE DAY GIVEN THE SLOWER TIMING. TEMPS ARE TRICKY SINCE THERE PROBABLY WILL BE SOME FILTERED SUNSHINE THROUGH MID/HIGH CLOUDS IN THE MORNING. WITH 850MB TEMPS PROGGED BETWEEN 10-12C...HIGH TEMPERATURES SHOULD BE ABLE TO REACH INTO THE LOW TO POSSIBLY MID 60S...A BLEND BETWEEN MAV AND MET GUIDANCE. WARMEST READINGS EXPECTED IN DOWNSLOPE SE FLOW AREAS... WITH COOLEST READINGS DOWNWIND OF LAKE MICHIGAN. IF MORE SUN OCCURS THAN CURRENTLY EXPECTED...SOME LOCATIONS COULD REACH THE UPPER 60S...SUCH AS PELKIE. .LONG TERM (TUE NIGHT THROUGH MONDAY)... TUE NIGHT INTO WED NIGHT...A MID LEVEL AND SFC TROUGH MOVING THROUGH THE UPPER GREAT LAKES WILL SUPPORT PCPN INTO THE CWA. ALTHOUGH THE STRONGER 900-600 MB FGEN OVER NW WI AND WRN LAKE SUPERIOR WEAKENS AS IT SLIDES TO THE EAST...A BROAD AREA OF 300-305K ISENTROPIC LIFT ALONG WITH STRONG MOISTURE INFLOW...BRINGING PWAT VALUES TO 1.00-1.25 INCHES WILL SUPPORT DECENT COVERAGE OF RAIN WITH LIKELY POPS INCLUDED IN THE FCST. ANY LEFTOVER RAIN IS EXPECTED TO DEPART THE CNTRL CWA WED MORNING AND IN THE AFTERNOON OVER THE EAST. A MORE ZONAL PATTERN WITH A MID LEVEL LOW AND SFC TROUGH MOVING THROUGH NRN MANITOBA INTO NW ONTARIO WILL RESULT IN DRY ADVECTION WITH WRLY FLOW. THU-MON...THE GLOBAL MODELS ARE INITIALLY IN AGREEMENT WITH PATTERN AMPLIFICATION AS A TROUGH DEVELOPS OVER THE WRN CONUS. HOWEVER...BY THE WEEKEND INTO MON SIGNIFICANT DIFFERENCES DEVELOP. THE 00Z AND 12Z ECMWF REMAIN SLOWER WITH THE PROGRESSION OF THE MID LEVEL TROUGH THAN THE GFS AND GFS ENSEMBLE MEAN WHICH IN ADDITION TO THE GLBL GEM PUSH A NORTHERN STREAM TROUGH THROUGH THE UPPER LAKES AND LEAVE A CUTOFF LOW OVER THE SW CONUS. SO...WITH LARGE UNCERTAINTY THE FCST CONTINUES TO LEAN MORE TOWARD A SLIGHTLY FASTER PROGRESSION OF THE ECMWF FAVORED BY HPC. BY SAT...HIGHER POPS ARE EXPECTED OVER THE WEST...CLOSER TO THE INVERTED TROF AXIS. 30-40 POPS ARE THEN INCLUDED THROUGH MON TO ACCOUNT FOR THE LARGE UNCERTAINTY. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... LOW IFR CIGS AT KSAW WERE TEMPORARY CAUSED BY RAIN AND ALSO A BIT OF USLOPE. LOW CLOUDS ACROSS NE WI/WESTERN MI HAVE BEEN ERODING AND LOOK FOR THIS TO CONTINUE. WILL ADD LLWS IN TONIGHT AT BOTH SITES WITH WINDS OFF THE SFC. AS FOR KCMX...SE WINDS ARE DOWNSLOPE FOR THEM...SO KEPT THE LOW CLOUDS OUT. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... BREEZY SE WINDS WILL CONTINUE ON LAKE SUPERIOR TONIGHT INTO MUCH OF TUE...ESPECIALLY ON THE EAST HALF...WHERE WINDS SPEEDS OF UP TO 30 KT ARE POSSIBLE. THE BREEZY WINDS ARE DUE TO A TIGHT PRESSURE GRADIENT BTWN HIGH PRESSURE OVER EASTERN ONTARIO AND A LOW PRESSURE TROUGH OVER FAR WESTERN MN. THIS TROUGH SHOULD BE MOVING INTO FAR WESTERN LAKE SUPERIOR LATE TUE AFTN...THEN CROSSING THE REST OF THE LAKE TUE NIGHT INTO WED MORNING. AS THE TROUGH CROSSES...EXPECT WINDS TO FALL BELOW 20 KT AND GRADUALLY SHIFT TO THE SW. FOR WED INTO THU...DEEPENING LOW PRESSURE WILL BE MOVING ACROSS CENTRAL CANADA TO HUDSON BAY...WHILE HIGH PRESSURE CROSSES THE SOUTHERN GREAT LAKES. THIS SETS UP AN INCREASING WEST WIND OVER LAKE SUPERIOR...POSSIBLY REACHING UP TO 30 KT WED NIGHT AND THU ACROSS THE NORTHERN PORTION OF THE LAKE. THE HIGH PRESSURE AREA OVER THE SOUTHERN GREAT LAKES SHOULD EXPAND UP INTO THE LAKE SUPERIOR ON FRI...BRINGING WINDS BACK DOWN BELOW 20 KT. A FRONTAL BOUNDARY WILL THEN SET UP OVER THE UPPER GREAT LAKES FRI NIGHT AND SAT. POSITION OF THIS BOUNDARY IS UNCERTAIN...BUT RIGHT NOW IT APPEARS THAT SE WINDS UP TO 25 KT MAY AFFECT LAKE SUPERIOR DURING THIS PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM...AJ LONG TERM...JLB AVIATION...GM MARINE...AJ mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 137 PM EDT MON OCT 6 2008 UPDATED AVIATION DISCUSSION FOR 18Z TAF ISSUANCE .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR RAIN TODAY AND TONIGHT. WATER VAPOR IMAGERY AND RUC SHOW A CLOSED LOW OVER NEW ENGLAND WITH AN ACCOMPANYING TROUGH EXTENDING WEST INTO THE LOWER GREAT LAKES. A LONGWAVE TROUGH STRETCHES FROM A LOW OVER SOUTHEAST COLORADO NORTHWEST ACROSS THE HIGH PLAINS INTO NORTHERN ALBERTA. A STEEP RIDGE SEPARATES THESE TWO SYSTEMS AND RUN FROM A HIGH OVER NORTHERN ONTARIO SOUTH THROUGH WISCONSIN INTO THE WEST END OF THE OHIO RIVER VALLEY. SURFACE FEATURES DEPICT A LARGE HIGH EMBEDDED OVER EASTERN ONTARIO BLANKETING MUCH OF THE GREAT LAKES REGION. A LOW AND ASSOCIATED FRONTAL SYSTEM REACHES FROM NORTH DAKOTAS SOUTH THROUGH THE CENTRAL PLAINS INTO WEST TEXAS. A THICK DECK OF CLOUDS HAVE MOVED ACROSS THE FORECAST AREA IN THE WAKE OF THE UPPER LEVEL JET. THE MODELS ARE IN A FAIRLY GOOD AGREEMENT IN THE EARLY PART OF THE FORECAST PERIOD. THE MID LEVEL RIDGE WILL SHIFT OVER UPPER MICHIGAN TODAY WHILE THE UPPER LEVEL JET SLIDES SOUTHEAST INTO THE MID ATLANTIC STATES. THE SURFACE HIGH WILL EDGE INTO SOUTHWEST QUEBEC. THE NORTHERN PLAINS FRONT WILL MANEUVER INTO WESTERN MINNESOTA. LOW LEVEL MOISTURE WILL CONTINUE TO BE DRAWN INTO THE AREA IN THE SOUTHERLY FLOW AHEAD OF THE FRONT AND WILL SHIFT ACROSS THE AREA. THE LOSS OF THE UPPER LEVEL SUPPORT FROM THE JET AND THE SHORTWAVE ENERGY MOVING THROUGH THE RIDGE WILL CAUSE THE CHANCE OF PRECIPITATION TO LESSEN DURING THE DAY. GUIDANCE SHOWING THE BEST CHANCE OF SHOWERS WILL BE OVER THE WEST THIS MORNING...AND WEAKENING DURING THE DAY. CLOUD COVER DURING THE DAY WILL HELP HOLD DOWN THE TEMPERATURES. TRAJECTORY FORECAST SUGGEST SOME WARM AIR ADVECTION. THUS WILL STICK FAIRLY CLOSE TO GUIDANCE...KEEPING TEMPERATURES IN THE UPPER 50S TO AROUND 760. THE MID LEVEL RIDGE WILL DIVERT INTO EASTERN ONTARIO AS THE NORTHERN PLAINS TROUGH SHIFTS INTO WESTERN MINNESOTA. THE COLD FRONT WILL TRACK INTO EASTERN MINNESOTA. THE FLOW AHEAD OF THE FRONT WILL CONTINUE TO DRAW WARM MOIST AIR INTO THE FORECAST AREA. AN UPPER LEVEL JET MAX WILL PUSH INTO WESTERN ONTARIO. DEEP MOISTURE WILL BE CONFINED TO THE AREA TO THE WEST OF THE FORECAST AREA. THE RIDGE WILL RELOCATE OVER WESTERN QUEBEC ON TUESDAY ALLOWING THE MID LEVEL TROUGH AND ASSOCIATED FRONTAL SYSTEM TO PUSH INTO THE WEST END OF THE FORECAST AREA ON TUESDAY. THE UPPER LEVEL JET MAX WILL BECOME FOCUSED OVER NORTH ONTARIO...AIMED AT THE UPPER GREAT LAKES AND CONTRIBUTE TO THE INSTABILITY OVER THE AREA. LOW LEVEL MOISTURE WILL CONTINUE TO FEED INTO THE AREA HEAD OF THE FRONT. SHORTWAVE ENERGY AND ISENTROPIC ASCENT AHEAD OF THE FRONT WILL COMBINED TO GENERATE SHOWERS OVER THE WEST HALF OF THE FORECAST AREA. THE SHORTWAVE AND FRONTAL SYSTEM WILL TREK THROUGH THE FORECAST AREA TUESDAY NIGHT AS IT WEAKENS AND WASHES OUT AS IT CRASHES INTO DRIER AND MORE STABLE AIR ASSOCIATED WITH THE LARGE RIDGE OVER THE EASTERN CONUS. ANOTHER TROUGH WILL DEVELOP OVER THE CANADIAN PRAIRIE AND SLIDE INTO SOUTHERN MANITOBA. A FRONTAL SYSTEM WILL ALSO DEVELOP OVER SOUTHERN MANITOBA AND THE NORTHERN PLAINS. SHOWERS WILL STILL BE POSSIBLE OVER THE FORECAST AREA ACCOMPANYING THE FROPA. PLAN TO KEEP CHANCE POPS GOING. THE MID LEVEL LOW WILL SPIN INTO CENTRAL MANITOBA ON WEDNESDAY WHILE THE COLD FRONT RACES THROUGH THE AREA. GUIDANCE CONTINUES TO KEEP SHOWER POSSIBILITY OVER THE AREA THROUGH WEDNESDAY WITH THE PASSAGE TO THE FRONT AND SHORTWAVE ENERGY. THE MID LEVEL LOW WILL SHIFT INTO NORTHERN MANITOBA WEDNESDAY NIGHT...WHILE SHORTWAVE ENERGY ROTATING THROUGH THE BASE OF THE LOW SWEEPS INTO THE FORECAST AREA. THIS INSTABILITY WILL CONTRIBUTE TO KEEPING A CHANCE OF SHOWERS GOING OVER THE EASTERN U.P. DRY AIR WILL ADVECT INTO THE AREA BEHIND THE FRONT AND SHOULD END THE CHANCES OF SHOWERS OVER THE WEST. DRY AIR WILL REMAIN IN PLACE ON THURSDAY AS A SURFACE RIDGE SETTLE OVER THE AREA AND THE SHORTWAVE ENERGY ROTATE TO THE EAST OF THE CWA ON THURSDAY. THURSDAY NIGHT AND FRIDAY SHOWING SOME DISAGREEMENT BETWEEN ECMWF AND GFS MODELS ON THE TRACK OF SURFACE FEATURES. THE ECMWF KEEPS A HIGH OVER THE AREA WHILE GFS IS BRINGING IN THE NEXT LOW PRESSURE SYSTEM. THE ECMWF HAS BEEN SHOWING A LITTLE BETTER CONTINUITY SO WILL FAVOR THE EC SOLUTION AND KEEP CONDITIONS DRY THROUGH FRIDAY. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... A DRY ESE FLOW AROUND HIGH PRESSURE DROPPING SOUTH ACROSS EASTERN ONTARIO WILL MAINTAIN VFR CONDITIONS THROUGH THE FORECAST PERIOD AT BOTH TAF SITES. HOWEVER...SOME MVFR STRATOCUMULUS POPPED UP THIS MORNING AT SAW...AND ALTHOUGH RECENT CALL TO THE SITE REPORTED NO MORE STRATOCUMULUS DECK...DECIDED TO LEAVE IN POTENTIAL FOR REDEVELOPMENT DURING THE NEXT FEW HOURS WITH SE FLOW OFF LAKE MI PROVIDING UPSLOPE. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... A E-SE GRADIENT BETWEEN HIGH PRESSURE SOUTH OF JAMES BAY...AND LOW PRESSURE OVER WESTERN SOUTH DAKOTA WILL RESULT IN WINDS UP TO 30 KNOTS OVER PORTIONS OF CENTRAL AND EASTERN LAKE SUPERIOR TODAY THROUGH TUESDAY MORNING. WINDS WILL DIE OFF TO 10 TO 20 KNOTS BY LATE TUE NIGHT AND WED AS THE LOW PRESSURE TROUGH FROM THE NRN PLAINS MOVES ACROSS THE LAKE. WRLY WINDS WILL INCREASE AGAIN TO 30 KNOTS OVER NRN PORTIONS OF THE LAKE THU AS THE GRADIENT TIGHTENS BETWEEN LOW PRESSURE OVER HUDSON BAY AND HIGH PRESSURE OVER THE CENTRAL PLAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE LAKE MICHIGAN...NONE. && $$ DISCUSSION...DLG AVIATION...AJ MARINE...VOSS mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 745 AM EDT MON OCT 6 2008 .DISCUSSION... THE MAIN CONCERN WITH THIS FORECAST PACKAGE IS THE POTENTIAL FOR RAIN TODAY AND TONIGHT. WATER VAPOR IMAGERY AND RUC SHOW A CLOSED LOW OVER NEW ENGLAND WITH AN ACCOMPANYING TROUGH EXTENDING WEST INTO THE LOWER GREAT LAKES. A LONGWAVE TROUGH STRETCHES FROM A LOW OVER SOUTHEAST COLORADO NORTHWEST ACROSS THE HIGH PLAINS INTO NORTHERN ALBERTA. A STEEP RIDGE SEPARATES THESE TWO SYSTEMS AND RUN FROM A HIGH OVER NORTHERN ONTARIO SOUTH THROUGH WISCONSIN INTO THE WEST END OF THE OHIO RIVER VALLEY. SURFACE FEATURES DEPICT A LARGE HIGH EMBEDDED OVER EASTERN ONTARIO BLANKETING MUCH OF THE GREAT LAKES REGION. A LOW AND ASSOCIATED FRONTAL SYSTEM REACHES FROM NORTH DAKOTAS SOUTH THROUGH THE CENTRAL PLAINS INTO WEST TEXAS. A THICK DECK OF CLOUDS HAVE MOVED ACROSS THE FORECAST AREA IN THE WAKE OF THE UPPER LEVEL JET. THE MODELS ARE IN A FAIRLY GOOD AGREEMENT IN THE EARLY PART OF THE FORECAST PERIOD. THE MID LEVEL RIDGE WILL SHIFT OVER UPPER MICHIGAN TODAY WHILE THE UPPER LEVEL JET SLIDES SOUTHEAST INTO THE MID ATLANTIC STATES. THE SURFACE HIGH WILL EDGE INTO SOUTHWEST QUEBEC. THE NORTHERN PLAINS FRONT WILL MANEUVER INTO WESTERN MINNESOTA. LOW LEVEL MOISTURE WILL CONTINUE TO BE DRAWN INTO THE AREA IN THE SOUTHERLY FLOW AHEAD OF THE FRONT AND WILL SHIFT ACROSS THE AREA. THE LOSS OF THE UPPER LEVEL SUPPORT FROM THE JET AND THE SHORTWAVE ENERGY MOVING THROUGH THE RIDGE WILL CAUSE THE CHANCE OF PRECIPITATION TO LESSEN DURING THE DAY. GUIDANCE SHOWING THE BEST CHANCE OF SHOWERS WILL BE OVER THE WEST THIS MORNING...AND WEAKENING DURING THE DAY. CLOUD COVER DURING THE DAY WILL HELP HOLD DOWN THE TEMPERATURES. TRAJECTORY FORECAST SUGGEST SOME WARM AIR ADVECTION. THUS WILL STICK FAIRLY CLOSE TO GUIDANCE...KEEPING TEMPERATURES IN THE UPPER 50S TO AROUND 760. THE MID LEVEL RIDGE WILL DIVERT INTO EASTERN ONTARIO AS THE NORTHERN PLAINS TROUGH SHIFTS INTO WESTERN MINNESOTA. THE COLD FRONT WILL TRACK INTO EASTERN MINNESOTA. THE FLOW AHEAD OF THE FRONT WILL CONTINUE TO DRAW WARM MOIST AIR INTO THE FORECAST AREA. AN UPPER LEVEL JET MAX WILL PUSH INTO WESTERN ONTARIO. DEEP MOISTURE WILL BE CONFINED TO THE AREA TO THE WEST OF THE FORECAST AREA. THE RIDGE WILL RELOCATE OVER WESTERN QUEBEC ON TUESDAY ALLOWING THE MID LEVEL TROUGH AND ASSOCIATED FRONTAL SYSTEM TO PUSH INTO THE WEST END OF THE FORECAST AREA ON TUESDAY. THE UPPER LEVEL JET MAX WILL BECOME FOCUSED OVER NORTH ONTARIO...AIMED AT THE UPPER GREAT LAKES AND CONTRIBUTE TO THE INSTABILITY OVER THE AREA. LOW LEVEL MOISTURE WILL CONTINUE TO FEED INTO THE AREA HEAD OF THE FRONT. SHORTWAVE ENERGY AND ISENTROPIC ASCENT AHEAD OF THE FRONT WILL COMBINED TO GENERATE SHOWERS OVER THE WEST HALF OF THE FORECAST AREA. THE SHORTWAVE AND FRONTAL SYSTEM WILL TREK THROUGH THE FORECAST AREA TUESDAY NIGHT AS IT WEAKENS AND WASHES OUT AS IT CRASHES INTO DRIER AND MORE STABLE AIR ASSOCIATED WITH THE LARGE RIDGE OVER THE EASTERN CONUS. ANOTHER TROUGH WILL DEVELOP OVER THE CANADIAN PRAIRIE AND SLIDE INTO SOUTHERN MANITOBA. A FRONTAL SYSTEM WILL ALSO DEVELOP OVER SOUTHERN MANITOBA AND THE NORTHERN PLAINS. SHOWERS WILL STILL BE POSSIBLE OVER THE FORECAST AREA ACCOMPANYING THE FROPA. PLAN TO KEEP CHANCE POPS GOING. THE MID LEVEL LOW WILL SPIN INTO CENTRAL MANITOBA ON WEDNESDAY WHILE THE COLD FRONT RACES THROUGH THE AREA. GUIDANCE CONTINUES TO KEEP SHOWER POSSIBILITY OVER THE AREA THROUGH WEDNESDAY WITH THE PASSAGE TO THE FRONT AND SHORTWAVE ENERGY. THE MID LEVEL LOW WILL SHIFT INTO NORTHERN MANITOBA WEDNESDAY NIGHT...WHILE SHORTWAVE ENERGY ROTATING THROUGH THE BASE OF THE LOW SWEEPS INTO THE FORECAST AREA. THIS INSTABILITY WILL CONTRIBUTE TO KEEPING A CHANCE OF SHOWERS GOING OVER THE EASTERN U.P. DRY AIR WILL ADVECT INTO THE AREA BEHIND THE FRONT AND SHOULD END THE CHANCES OF SHOWERS OVER THE WEST. DRY AIR WILL REMAIN IN PLACE ON THURSDAY AS A SURFACE RIDGE SETTLE OVER THE AREA AND THE SHORTWAVE ENERGY ROTATE TO THE EAST OF THE CWA ON THURSDAY. THURSDAY NIGHT AND FRIDAY SHOWING SOME DISAGREEMENT BETWEEN ECMWF AND GFS MODELS ON THE TRACK OF SURFACE FEATURES. THE ECMWF KEEPS A HIGH OVER THE AREA WHILE GFS IS BRINGING IN THE NEXT LOW PRESSURE SYSTEM. THE ECMWF HAS BEEN SHOWING A LITTLE BETTER CONTINUITY SO WILL FAVOR THE EC SOLUTION AND KEEP CONDITIONS DRY THROUGH FRIDAY. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... A DRY ESE FLOW AROUND HIGH PRESSURE DROPPING SOUTH OF JAMES BAY SHOULD YIELD VFR CONDITIONS AT BOTH TAF SITES...ALTHOUGH A BAND OF MOISTURE MOVING UP FROM WI COULD LOWER CIGS TO 4-5KFT BY EARLY AFTERNOON. AS THE S-SE PRESSURE GRADIENT INCREASES...WIND GUSTS NEAR 20 KNOTS CAN BE EXPECTED BY LATE THIS MORNING. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... A E-SE GRADIENT BETWEEN HIGH PRESSURE SOUTH OF JAMES BAY...AND LOW PRESSURE OVER WESTERN SOUTH DAKOTA WILL RESULT IN WINDS UP TO 30 KNOTS OVER PORTIONS OF CENTRAL AND EASTERN LAKE SUPERIOR TODAY THROUGH TUESDAY MORNING. WINDS WILL DIE OFF TO 10 TO 20 KNOTS BY LATE TUE NIGHT AND WED AS THE LOW PRESSURE TROUGH FROM THE NRN PLAINS MOVES ACROSS THE LAKE. WRLY WINDS WILL INCREASE AGAIN TO 30 KNOTS OVER NRN PORTIONS OF THE LAKE THU AS THE GRADIENT TIGHTENS BETWEEN LOW PRESSURE OVER HUDSON BAY AND HIGH PRESSURE OVER THE CENTRAL PLAINS. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE LAKE MICHIGAN...NONE. && $$ DISCUSSION...DLG AVIATION...VOSS MARINE...VOSS mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 134 PM EDT SUN OCT 5 2008 UPDATED FOR THE 18Z TAF ISSUANCE .DISCUSSION (ISSUED AT 335 AM EDT)... THE MAIN CONCERN WITH THE HIGH TEMPERATURES FOR TODAY AND PRECIPITATION POTENTIAL FOR TONIGHT. WATER VAPOR IMAGERY AND RUC ANALYSIS CLOSED LOW OVER WEST CENTRAL QUEBEC...A RIDGE EXTENDING NORTH FROM MISSOURI INTO EASTERN MANITOBA. A LONGWAVE TROUGH IS OVER ROCKIES. A SURFACE ANALYSIS DEPICTS A HIGH OVER NORTHERN ONTARIO AND BLANKETS MUCH OF THE GREAT LAKES REGION AND A LOW OVER THE NEBRASKA PANHANDLE. A STATIONARY FRONT EXTENDS EAST FROM THIS LOW ACROSS MIDDLE MISSISSIPPI RIVER VALLEY AND THE SOUTHERN OHIO RIVER VALLEY. A TROUGH ALSO STRETCHES NORTHWEST FROM THE SAME LOW INTO NORTHERN BRITISH COLUMBIA. A WEAK MID LEVEL TROUGH ROTATING AROUND THE QUEBEC LOW IS SWEEPING THROUGH LAKE SUPERIOR AND CENTRAL ONTARIO PRODUCING SOME CLOUD COVER OVER THE AREA TONIGHT. SEVERAL WEAK SHORTWAVES ARE BEING EJECTED OUT OF THE TROUGH OVER THE ROCKIES AND ARE OVER THE CENTRAL PLAINS. ONE OF THE SHORTWAVES EJECTED OUT OF THE ROCKIES TROUGH WILL APPROACH THE RIDGE AND BECOME FOCUSED OVER THE IOWA AND SOUTHERN MINNESOTA LATE TODAY. DEEP MOISTURE ACCOMPANIES THE SHORTWAVE. THE QUEBEC LOW WILL SETTLE SOUTH INTO EAST CENTRAL ONTARIO...WHILE HOLDING THE MINNESOTA RIDGE STATIONARY. AS THIS LOW SETTLE SOUTH...THE HIGH OVER ONTARIO WILL SHIFT A LITTLE EAST INTO JAMES BAY. THIS WILL ALSO HOLD THE LOW OVER THE CENTRAL PLAINS STATIONARY AS WELL. THE SHORTWAVE IN THE RIDGE WILL SLIDE SOUTHEAST INTO WISCONSIN AND SOUTHERN LOWER MICHIGAN. PRECIPITABLE WATER IN EXCESS OF 1 INCH WILL BLANKET MUCH OVER THE DAKOTAS...SOUTHERN MINNESOTA AND SOUTHERN WISCONSIN. OVER THE FORECAST AREA...CONDITIONS WILL BE DRIER AND MORE STABLE. THUS PLAN TO KEEP THE CWA DRY. THERE SHOULD BE SOME CLOUD COVER TODAY...MAINLY OVER THE EASTERN CWA CLOSER TO SHORTWAVE WRAPPING AROUND THE ONTARIO LOW. SOUNDING FORECAST SUGGEST THIS WILL BE MAINLY AC. IT SHOULD BE A LITTLE WARMER OVER THE WEST WHERE THERE SHOULD BE MORE SUN. THE MID LEVEL LOW OVER EASTERN ONTARIO WILL SETTLE INTO SOUTHEAST ONTARIO TONIGHT ALLOWING THE RIDGE OVER MINNESOTA TO EDGE EAST INTO WESTERN LAKE SUPERIOR. THE HIGH OVER JAMES BAY WILL SETTLE A LITTLE SOUTH ALSO INTO EAST CENTRAL ONTARIO. THE LOW OVER CENTRAL PLAINS WILL LIFT INTO THE DAKOTAS. A JET MAX WILL SLIDE ACROSS THE FORECAST AREA. PLACING THE STRONGEST UPPER LEVEL DIVERGENCE OVER WISCONSIN. GFS/NAM SHOWING THAT THE DEEP MOISTURE FIELD AND SHORTWAVE ENERGY WILL REACH TO JUST SOUTH OF THE WISCONSIN/U.P. BORDER. FOR NOW THE SHOWERS SHOULD STAY JUST TO THE SOUTHWEST OF THE FORECAST AREA. THE CLOSE PROXIMITY OF THE SHORTWAVE ENERGY WILL SUGGEST THAT THERE SHOULD BE PLENTY OF CLOUD COVER. THE MID LEVEL LOW OVER SOUTHEAST ONTARIO WILL SHIFT EAST INTO SOUTHERN QUEBEC ON MONDAY...ALLOWING THE RIDGE TO PUSH INTO CENTRAL ONTARIO AND THE FORECAST AREA. THE DAKOTA LOW WILL DEVELOP INTO A LONGWAVE TROUGH OVER THE WESTERN DAKOTAS. A LOW WILL ALSO DEVELOP IN THIS TROUGH OVER KANSAS. THE SURFACE HIGH WILL REMAIN OVER EAST CENTRAL ONTARIO SLOWING THE PROGRESS OF THE DAKOTAS TROUGH SO IT WILL ONLY REACH THE DAKOTAS/MINNESOTA BORDER. MODELS CONTINUE TO SHOW THAT THE DEEP MOISTURE WILL STAY JUST TO THE WEST OF THE FORECAST AREA. THE MID LEVEL TROUGH WILL PUSH INTO EASTERN DAKOTAS AND THE ASSOCIATED LOW OVER KANSAS WILL LIFT INTO NEBRASKA MONDAY NIGHT. THE SURFACE HIGH WILL DRIFT TO JUST NORTH OF LAKE ONTARIO. THE SURFACE TROUGH WILL DEEPEN INTO A WEAK FRONTAL SYSTEM AS IT TREKS INTO MINNESOTA BEHIND THE HIGH. TOGETHER THESE WILL PRODUCE A SOUTHERLY FLOW DRAWING WARMER TEMPERATURES INTO THE AREA AND DEEP MOISTURE INTO MINNESOTA AND WESTERN WISCONSIN. THE MOISTURE AND INSTABILITY JUST WEST OF THE FORECAST AREA WILL KEEP RAIN OUT OF THE FORECAST FOR NOW. THE MID LEVEL RIDGE WILL PUSH INTO EASTERN ONTARIO ON TUESDAY. THE CLOSED LOW WILL SHIFT INTO SOUTHWEST MISSOURI. THE ACCOMPANYING WEAK TROUGH WILL RELOCATE OVER NORTHERN MINNESOTA. A WEAK RIDGE FOLLOWING THE TROUGH WILL ALSO PUSH INTO MANITOBA. THIS WILL ALLOW SOME WEAK TROUGH ACCOMPANYING THIS SYSTEM WILL SETTLE OVER THE WESTERN U.P. AND LAKE SUPERIOR. THE SURFACE RIDGE WILL MOVE EAST BLANKETING MUCH OF THE EAST COAST. THE COLD FRONT WILL TRACK INTO WESTERN LAKE SUPERIOR. THE SOUTHERLY FLOW WILL CONTINUE TO DRAW WARM MOIST AIR IN THE FORECAST AREA. THUS WITH THE INSTABILITY OVER THE WESTERN U.P. AND THE AVAILABLE MOISTURE...I PLAN TO START TO CALL FOR SOME SHOWERS OVER THE WESTERN U.P. ON TUESDAY. THE CUT OFF LOW OVER MISSOURI WILL MOVE INTO THE MIDDLE MISSISSIPPI RIVER VALLEY TUESDAY NIGHT. THE ACCOMPANYING TROUGH OVER MINNESOTA WILL WEAKEN EVEN MORE AS IT SHIFTS OVER THE FORECAST AREA. THIS LOW WILL DRAW MORE OF THE WARM MOIST GULF AIR INTO THE UPPER GREAT LAKES REGION. THE COLD FRONT WILL SWEEP ACROSS MUCH OF THE FORECAST AREA. THUS CHANCE OF SHOWERS APPEARS TO BE MORE LIKELY...SO WILL CALL FOR SHOWERS ACROSS MUCH OF THE AREA. THE CLOSED LOW OVER MISSOURI WILL RELOCATE OVER SOUTHERN ILLINOIS ON WEDNESDAY. WEAK SHORTWAVE ENERGY WILL RACE ACROSS THE FORECAST AREA. THE SURFACE LOW WILL EDGE INTO NORTHEAST MANITOBA. THE ASSOCIATED COLD FRONT WILL SLIDE INTO LOWER MICHIGAN. THERE WILL STILL BE ENOUGH LOW LEVEL MOISTURE ACCOMPANYING THIS SHORTWAVE INSTABILITY AND THE FRONTAL SYSTEM...TO KEEP A CHANCE OF SHOWERS IN THE FORECASTS. GFS GUIDANCE CALLING FOR A CHANCE OF SHOWERS ON WEDNESDAY. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... EXPECT VFR CONDITIONS TO PREVAIL AT KCMX/KSAW THROUGH THE FCST PERIOD AS A DRY EASTERLY FLOW CONTINUES AROUND HIGH PRESSURE DROPPING SOUTH OF JAMES BAY. TOWARDS THE END OF THE PERIOD...AS THE PRESSURE GRADIENT INCREASES...WIND GUSTS NEAR 20 KNOTS CAN BE EXPECTED...ALONG WITH LOWERING CEILINGS THAT SHOULD STILL REMAIN VFR. PRECIPITATION MAY BE NEEDED AFTER 18Z OR SLIGHTLY BEFORE...HAVE ADDED PROB30 AFTER 17Z. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... LIGHT WIND REGIME OVER LAKE SUPERIOR UNDER A HIGH PRES RIDGE WILL GIVE WAY TO INCREASING ERLY WINDS TONIGHT THRU MON NIGHT AS A HIGH PRES CENTER BUILDS E OF LAKE SUPERIOR OVER THE ONTARIO/QUEBEC BORDER. LOOK FOR THE STRONGEST WINDS TO OCCUR OVER WRN LAKE SUPERIOR DURING THIS PATTERN...BTWN THE APOSTLE ISLANDS AND THE MN SHORE. WINDS SHOULD REACH 30KT BY SUN EVENING. THE STRONGEST WINDS WILL THEN SHIFT TO CNTRL AND ERN LAKE SUPERIOR MON/TUE AS WINDS VEER SE AHEAD OF APPROACHING TROF. PRES GRADIENT SLACKENS TUE NIGHT THRU THU AS A TROF PASSES THRU THE UPPER LAKES. EXPECT WINDS GENERALLY IN THE 10-20KT RANGE WITH OCCASIONAL 15-25KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE LAKE MICHIGAN...NONE. && $$ DISCUSSION...DLG AVIATION...KF MARINE...VOSS mi AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MARQUETTE MI 732 AM EDT SUN OCT 5 2008 .DISCUSSION... THE MAIN CONCERN WITH THE HIGH TEMPERATURES FOR TODAY AND PRECIPITATION POTENTIAL FOR TONIGHT. WATER VAPOR IMAGERY AND RUC ANALYSIS CLOSED LOW OVER WEST CENTRAL QUEBEC...A RIDGE EXTENDING NORTH FROM MISSOURI INTO EASTERN MANITOBA. A LONGWAVE TROUGH IS OVER ROCKIES. A SURFACE ANALYSIS DEPICTS A HIGH OVER NORTHERN ONTARIO AND BLANKETS MUCH OF THE GREAT LAKES REGION AND A LOW OVER THE NEBRASKA PANHANDLE. A STATIONARY FRONT EXTENDS EAST FROM THIS LOW ACROSS MIDDLE MISSISSIPPI RIVER VALLEY AND THE SOUTHERN OHIO RIVER VALLEY. A TROUGH ALSO STRETCHES NORTHWEST FROM THE SAME LOW INTO NORTHERN BRITISH COLUMBIA. A WEAK MID LEVEL TROUGH ROTATING AROUND THE QUEBEC LOW IS SWEEPING THROUGH LAKE SUPERIOR AND CENTRAL ONTARIO PRODUCING SOME CLOUD COVER OVER THE AREA TONIGHT. SEVERAL WEAK SHORTWAVES ARE BEING EJECTED OUT OF THE TROUGH OVER THE ROCKIES AND ARE OVER THE CENTRAL PLAINS. ONE OF THE SHORTWAVES EJECTED OUT OF THE ROCKIES TROUGH WILL APPROACH THE RIDGE AND BECOME FOCUSED OVER THE IOWA AND SOUTHERN MINNESOTA LATE TODAY. DEEP MOISTURE ACCOMPANIES THE SHORTWAVE. THE QUEBEC LOW WILL SETTLE SOUTH INTO EAST CENTRAL ONTARIO...WHILE HOLDING THE MINNESOTA RIDGE STATIONARY. AS THIS LOW SETTLE SOUTH...THE HIGH OVER ONTARIO WILL SHIFT A LITTLE EAST INTO JAMES BAY. THIS WILL ALSO HOLD THE LOW OVER THE CENTRAL PLAINS STATIONARY AS WELL. THE SHORTWAVE IN THE RIDGE WILL SLIDE SOUTHEAST INTO WISCONSIN AND SOUTHERN LOWER MICHIGAN. PRECIPITABLE WATER IN EXCESS OF 1 INCH WILL BLANKET MUCH OVER THE DAKOTAS...SOUTHERN MINNESOTA AND SOUTHERN WISCONSIN. OVER THE FORECAST AREA...CONDITIONS WILL BE DRIER AND MORE STABLE. THUS PLAN TO KEEP THE CWA DRY. THERE SHOULD BE SOME CLOUD COVER TODAY...MAINLY OVER THE EASTERN CWA CLOSER TO SHORTWAVE WRAPPING AROUND THE ONTARIO LOW. SOUNDING FORECAST SUGGEST THIS WILL BE MAINLY AC. IT SHOULD BE A LITTLE WARMER OVER THE WEST WHERE THERE SHOULD BE MORE SUN. THE MID LEVEL LOW OVER EASTERN ONTARIO WILL SETTLE INTO SOUTHEAST ONTARIO TONIGHT ALLOWING THE RIDGE OVER MINNESOTA TO EDGE EAST INTO WESTERN LAKE SUPERIOR. THE HIGH OVER JAMES BAY WILL SETTLE A LITTLE SOUTH ALSO INTO EAST CENTRAL ONTARIO. THE LOW OVER CENTRAL PLAINS WILL LIFT INTO THE DAKOTAS. A JET MAX WILL SLIDE ACROSS THE FORECAST AREA. PLACING THE STRONGEST UPPER LEVEL DIVERGENCE OVER WISCONSIN. GFS/NAM SHOWING THAT THE DEEP MOISTURE FIELD AND SHORTWAVE ENERGY WILL REACH TO JUST SOUTH OF THE WISCONSIN/U.P. BORDER. FOR NOW THE SHOWERS SHOULD STAY JUST TO THE SOUTHWEST OF THE FORECAST AREA. THE CLOSE PROXIMITY OF THE SHORTWAVE ENERGY WILL SUGGEST THAT THERE SHOULD BE PLENTY OF CLOUD COVER. THE MID LEVEL LOW OVER SOUTHEAST ONTARIO WILL SHIFT EAST INTO SOUTHERN QUEBEC ON MONDAY...ALLOWING THE RIDGE TO PUSH INTO CENTRAL ONTARIO AND THE FORECAST AREA. THE DAKOTA LOW WILL DEVELOP INTO A LONGWAVE TROUGH OVER THE WESTERN DAKOTAS. A LOW WILL ALSO DEVELOP IN THIS TROUGH OVER KANSAS. THE SURFACE HIGH WILL REMAIN OVER EAST CENTRAL ONTARIO SLOWING THE PROGRESS OF THE DAKOTAS TROUGH SO IT WILL ONLY REACH THE DAKOTAS/MINNESOTA BORDER. MODELS CONTINUE TO SHOW THAT THE DEEP MOISTURE WILL STAY JUST TO THE WEST OF THE FORECAST AREA. THE MID LEVEL TROUGH WILL PUSH INTO EASTERN DAKOTAS AND THE ASSOCIATED LOW OVER KANSAS WILL LIFT INTO NEBRASKA MONDAY NIGHT. THE SURFACE HIGH WILL DRIFT TO JUST NORTH OF LAKE ONTARIO. THE SURFACE TROUGH WILL DEEPEN INTO A WEAK FRONTAL SYSTEM AS IT TREKS INTO MINNESOTA BEHIND THE HIGH. TOGETHER THESE WILL PRODUCE A SOUTHERLY FLOW DRAWING WARMER TEMPERATURES INTO THE AREA AND DEEP MOISTURE INTO MINNESOTA AND WESTERN WISCONSIN. THE MOISTURE AND INSTABILITY JUST WEST OF THE FORECAST AREA WILL KEEP RAIN OUT OF THE FORECAST FOR NOW. THE MID LEVEL RIDGE WILL PUSH INTO EASTERN ONTARIO ON TUESDAY. THE CLOSED LOW WILL SHIFT INTO SOUTHWEST MISSOURI. THE ACCOMPANYING WEAK TROUGH WILL RELOCATE OVER NORTHERN MINNESOTA. A WEAK RIDGE FOLLOWING THE TROUGH WILL ALSO PUSH INTO MANITOBA. THIS WILL ALLOW SOME WEAK TROUGH ACCOMPANYING THIS SYSTEM WILL SETTLE OVER THE WESTERN U.P. AND LAKE SUPERIOR. THE SURFACE RIDGE WILL MOVE EAST BLANKETING MUCH OF THE EAST COAST. THE COLD FRONT WILL TRACK INTO WESTERN LAKE SUPERIOR. THE SOUTHERLY FLOW WILL CONTINUE TO DRAW WARM MOIST AIR IN THE FORECAST AREA. THUS WITH THE INSTABILITY OVER THE WESTERN U.P. AND THE AVAILABLE MOISTURE...I PLAN TO START TO CALL FOR SOME SHOWERS OVER THE WESTERN U.P. ON TUESDAY. THE CUT OFF LOW OVER MISSOURI WILL MOVE INTO THE MIDDLE MISSISSIPPI RIVER VALLEY TUESDAY NIGHT. THE ACCOMPANYING TROUGH OVER MINNESOTA WILL WEAKEN EVEN MORE AS IT SHIFTS OVER THE FORECAST AREA. THIS LOW WILL DRAW MORE OF THE WARM MOIST GULF AIR INTO THE UPPER GREAT LAKES REGION. THE COLD FRONT WILL SWEEP ACROSS MUCH OF THE FORECAST AREA. THUS CHANCE OF SHOWERS APPEARS TO BE MORE LIKELY...SO WILL CALL FOR SHOWERS ACROSS MUCH OF THE AREA. THE CLOSED LOW OVER MISSOURI WILL RELOCATE OVER SOUTHERN ILLINOIS ON WEDNESDAY. WEAK SHORTWAVE ENERGY WILL RACE ACROSS THE FORECAST AREA. THE SURFACE LOW WILL EDGE INTO NORTHEAST MANITOBA. THE ASSOCIATED COLD FRONT WILL SLIDE INTO LOWER MICHIGAN. THERE WILL STILL BE ENOUGH LOW LEVEL MOISTURE ACCOMPANYING THIS SHORTWAVE INSTABILITY AND THE FRONTAL SYSTEM...TO KEEP A CHANCE OF SHOWERS IN THE FORECASTS. GFS GUIDANCE CALLING FOR A CHANCE OF SHOWERS ON WEDNESDAY. && .AVIATION (FOR THE 12Z TAF ISSUANCE)... EXPECT VFR CONDITIONS TO PREVAIL AT KCMX/KSAW THROUGH THE FCST PERIOD AS A DRY ERLY FLOW CONTINUES AROUND HIGH PRESSURE DROPPING SOUTH OF JAMES BAY. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... LIGHT WIND REGIME OVER LAKE SUPERIOR UNDER A HIGH PRES RIDGE WILL GIVE WAY TO INCREASING ERLY WINDS TONIGHT THRU MON NIGHT AS A HIGH PRES CENTER BUILDS E OF LAKE SUPERIOR OVER THE ONTARIO/QUEBEC BORDER. LOOK FOR THE STRONGEST WINDS TO OCCUR OVER WRN LAKE SUPERIOR DURING THIS PATTERN...BTWN THE APOSTLE ISLANDS AND THE MN SHORE. WINDS SHOULD REACH 30KT BY SUN EVENING. THE STRONGEST WINDS WILL THEN SHIFT TO CNTRL AND ERN LAKE SUPERIOR MON/TUE AS WINDS VEER SE AHEAD OF APPROACHING TROF. PRES GRADIENT SLACKENS TUE NIGHT THRU THU AS A TROF PASSES THRU THE UPPER LAKES. EXPECT WINDS GENERALLY IN THE 10-20KT RANGE WITH OCCASIONAL 15-25KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE LAKE MICHIGAN...NONE. && $$ DISCUSSION...DLG AVIATION...GM MARINE...VOSS mi AREA FORECAST DISCUSSION...UPDATED AVIATION DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 209 AM EDT SUN OCT 5 2008 .SYNOPSIS... WATER VAPOR IMAGERY AND RUC ANALYSIS CONTINUE TO SHOW AN AMPLIFIED PATTERN OVER NAMERICA...FEATURING A TROF ALONG THE W COAST...A PRONOUNCED RIDGE EXTENDING N THRU CNTRL CANADA AND A TROF OVER THE NE CONUS/ERN CANADA. ON THE BACKSIDE OF THE ERN TROF...A SHORTWAVE WAS DROPPING S THRU NRN ONTARIO. ASSOCIATED JET STREAK WAS SUPPORTING A RIBBON OF -SHRA FROM NW OF CYQT TO THE MANITOBA BORDER. PCPN HAS DIMINISHED IN COVERAGE/INTENSITY FROM EARLIER TODAY...AND THE MID CLOUD DECK HAS HAD A TOUGH TIME SPREADING SE TO UPPER MI. OTHERWISE...LAKE EFFECT -SHRA OVER LAKE SUPERIOR INTO NCNTRL UPPER MI HAVE TRANSITIONED TO JUST INLAND -SHRA (SPRINKLES NOW)...TYPICAL OF EARLY SEASON LAKE EFFECT PCPN AS DAYTIME HEATING DISRUPTS LAKE EFFECT PROCESSES. && .SHORT TERM (TONIGHT/SUN)... SMALL BATCH OF PCPN TO THE NW SHOULDN`T BE AN ISSUE HERE TONIGHT AS FORCING IS TO WEAKEN...AND THAT APPEARS ON TRACK GIVEN DIMINISHING PCPN TRENDS EVIDENT ON RADAR IMAGERY OVER THE LAST FEW HRS. IN ADDITION...ANTECEDENT DRY AIRMASS SHOULD ALSO WORK TO LIMIT PCPN (AFTN TAMDAR SOUNDING FROM KCMX SHOWED A PRONOUNCED WEDGE OF DRY AIR WITH DWPT DEPRESSIONS UPWARDS OF 33C AROUND 750MB). OTHERWISE...WITH 850MB TEMPS TONIGHT EXPECTED TO RANGE FROM AROUND -1C E TO 2C W... THERE WILL STILL BE MARGINAL CONDITIONS FOR LAKE EFFECT -SHRA TO REDEVELOP OVER ERN LAKE SUPERIOR. AT THE SFC...NNW-SSE ORIENTED HIGH PRES RIDGE AXIS WILL REMAIN ACROSS CNTRL/ERN LAKE SUPERIOR... ESPECIALLY THRU THE FIRST PART OF THE NIGHT. THIS WILL ALLOW LAND BREEZES TO DEVELOP WHICH SHOULD RESULT IN ANY DEVELOPING LAKE EFFECT -SHRA REMAINING OFFSHORE. LATE TONIGHT...IT`S POSSIBLE A FEW -SHRA MAY REACH PORTIONS OF NCNTRL UPPER MI OR THE KEWEENAW AS LIGHT ERLY GRADIENT FLOW DEVELOPS DUE TO HIGH PRES RIDGE DRIFTING E A BIT. HOWEVER...GIVEN THE MARGINAL OVERLAKE INSTABILITY AND POTENTIAL FOR LAND BREEZES TO HOLD DOMINATE THRU THE NIGHT AS SUGGESTED BY THE RUC13...WILL MAINTAIN A DRY FCST. INLAND...CALM WINDS AND LIMITED CLOUD COVER FOR AT LEAST A PORTION OF THE NIGHT WILL RESULT IN ANOTHER CHILLY NIGHT. FAVORED THE LOWER END OF AVBL MOS GUIDANCE FOR MINS. MAY SEE SOME UPPER 20S IN THE USUAL COLD SPOTS. SUN...MID/UPPER RIDGE CURRENTLY EXTENDING N THRU CNTRL CANADA WILL CLOSE OFF INTO A HIGH IN THE VCNTY OF NE MANITOBA WHILE THE ERN TROF WILL BECOME REORIENTED WITH AXIS FROM THE UPPER LAKES/ONTARIO TO NEW ENGLAND/SRN QUEBEC. FOR THE LAST SEVERAL DAYS...ALL THE MODELS HAVE STRUGGLED WITH THE SHAPE OF UPSTREAM RIDGE/CLOSED HIGH AND LOCATION/ORIENTATION OF THE DOWNSTREAM TROF AXIS. THIS HAS BEEN IMPORTANT FOR THE FCST HERE BECAUSE THE LOCATION OF THE JET ASSOCIATED WITH THE TROF WILL SERVE TO FOCUS A BAND OF PCPN UNDER A RATHER IMPRESSIVE UPPER DIVERGENCE AREA IN THE RIGHT ENTRANCE OF THE JET AND IN A ZONE OF LOW/MID LEVEL FRONTOGENESIS. THE DIFFICULTY THE MODELS HAVE HAD WITH THIS EVOLVING PATTERN HAS RESULTED IN SUCCESSIVE RUNS OFTEN FLIP FLOPPING FROM A DRY FCST TO A WET FCST ACROSS UPPER MI. AS THIS PATTERN EVOLVES SUN...THERE IS MODEL AGREEMENT NOW THAT FORCING WILL BE FOCUSED WELL SW OF HERE. IN ADDITION...STRENGTHENING SFC HIGH ACROSS ONTARIO DOWNSTREAM OF DEVELOPING MID/UPPER HIGH WILL PROVIDE A FEED OF DRY AIR INTO THE AREA. WILL THUS MAINTAIN A DRY FCST SUN. MODERATING AIRMASS WILL LEAD TO WARMER CONDITIONS. ETA MOS NUMBERS LOOK REASONABLE FOR MAX TEMPS. && .LONG TERM (SUNDAY NIGHT THROUGH SATURDAY)... THE HIGH AMPLITUDE 500MB RIDGE CURRENTLY OVER CENTRAL CANADA AND THE CENTRAL UNITED STATES WILL SHIFT EASTWARD. IT WILL BE OVER THE UPPER GREAT LAKES REGION MONDAY AFTERNOON...BEING PUSHED FARTHER EASTWARD BY A CUT OFF LOW THAT FORMED LATE SUNDAY NIGHT ACROSS EASTERN COLORADO AND WESTERN KANSAS. THE RESULT FOR UPPER MICHIGAN WILL CONTINUE TO BE DRY WEATHER...WITH DRY EASTERLY WINDS CONTINUING THE DRY OUT THE LOWER LEVELS OF THE ATMOSPHERE. AFTERNOON HIGH TEMPERATURES SLOWLY RISING FROM THE 40S AND 50S OF LATE...TO THE LOWER 60S FROM MONDAY THROUGH THE END OF THE WORK WEEK. THE 500MB RIDGE WILL INEVITABLY SLIDE TO THE LOWER GREAT LAKES BY TUESDAY AFTERNOON...ALLOWING THE TROUGH OF LOW PRESSURE AND ITS ASSOCIATED MOISTURE BACK INTO THE UPPER GREAT LAKES FOR MID WEEK. BY 12Z TUESDAY...COLD FRONT SHOULD STRETCH FROM NORTHEASTERN MANITOBA THROUGH EASTERN NORTH DAKOTA TO NORTHERN OKLAHOMA. THIS WILL BE FAIRLY WEAK AS IT CROSSES UPPER MICHIGAN SOMETIME EARLY WEDNESDAY MORNING...BUT WILL SHIFT WINDS TO A SOUTHWESTERLY DIRECTION AND INCREASE MOISTURE A LITTLE MORE. THE GFS...BEING FASTER...IS STRONGEST WITH THIS FEATURE WEDNESDAY MORNING. WEDNESDAY THROUGH SATURDAY...PER HPC GUIDANCE A BLEND OF THE 00Z/04 GFS AND ECMWF RUNS WAS UTILIZED THIS PERIOD...DAY 4/WEDNESDAY THROUGH DAY 5/SATURDAY. THE EXACT TIMING OF THE NEXT SIGNIFICANT FRONTAL PASSAGE REMAINS PROBLEMATIC...WITH MODELS DIFFERING ON THE POSITION OF THE SFC LOW BY ROUGHLY 500 MILES BY 12Z THURSDAY. THE 06Z/04 GFS AND 00Z/04 CANADIAN HAD THE LOW LOCATED OVER HUDSON BAY...WHILE THE 00Z/04 ECMWF STILL HAD THIS FEATURE OVER CENTRAL MANITOBA. BOTH THE 12Z/04 GFS AND NAM TRENDED SLIGHTLY FASTER. STILL GRID WISE...FEW CHANGES WERE NEEDED. && .AVIATION (FOR THE 00Z TAF ISSUANCE)... EXPECT VFR CONDITIONS TO PREVAIL AT KCMX/KSAW DURING THIS FCST PERIOD WITH MID CLOUDS DEPARTING LATE TONIGHT ASSOCIATED WITH A SHORTWAVE THAT WILL BE MOVING OUT LATE TONIGHT. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... LIGHT WIND REGIME OVER LAKE SUPERIOR UNDER HIGH PRES RIDGE WILL GIVE WAY TO INCREASING ERLY WINDS TONIGHT THRU MON NIGHT AS HIGH PRES CENTER BUILDS TO THE E OF LAKE SUPERIOR. UNDER SUCH A PATTERN...THE STRONGEST WINDS WILL OCCUR OVER THE WRN LAKE BTWN THE APOSTLE ISLANDS AND THE MN SHORE. WINDS SHOULD REACH 30KT LATE SUN AFTN AND SUN NIGHT. MAY SEE A FEW GALE GUSTS TO AROUND 35KT LOCALLY. STRONGEST WINDS WILL THEN SHIFT TO CNTRL AND ERN LAKE SUPERIOR MON/TUE AS WINDS VEER SE AHEAD OF APPROACHING TROF. PRES GRADIENT SLACKENS TUE NIGHT THRU THU AS A TROF PASSES THRU THE UPPER LAKES. EXPECT WINDS GENERALLY IN THE 10-20KT RANGE WITH OCCASIONAL 15-25KT. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE LAKE MICHIGAN...NONE. && $$ SHORT TERM...ROLFSON LONG TERM...KF AVIATION...GM MARINE...ROLFSON mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 1107 PM CDT SUN OCT 5 2008 .AVIATION...06Z TAF. FORECAST REMAINS ON TARGET FOR A SIGNIFICANT RAIN EVENING DURING THE DAY MONDAY AND MONDAY NIGHT. IN THE MEAN TIME...LOOK FOR PASSING SHOWERS AND VFR CIGS AROUND 8K. LOOK FOR MVFR CIGS TO SETTLE MONDAY MORNING AS THE RAIN BEGINS IN EARNEST. OCCASIONAL IFR CIGS AND VSBYS WILL BE NOTED DURING MORE INTENSE RAIN AND ISOLATED STORM EVENTS MONDAY. && .PREV DISCUSSION... /ISSUED 927 PM CDT SUN OCT 5 2008/ UPDATE...JUST A SHORT COMMENT REGARDING PRECIPITATION. CWFA HAS STRUGGLED WITH RAINFALL DEVELOPMENT...ALTHOUGH THERE HAS BEEN A BIT MORE IN THE LAST 30 MINUTES OR SO OVER THE WESTERN/NORTHERN CWFA. OPTED TO LOWER PRECIPITATION COVERAGE IN THE NEXT FEW HOURS AS A LARGE PART OF THE CWFA WILL EXPERIENCE ONLY VERY LIGHT SHOWERS. BY FAR...THE MAIN RAIN EVENT WILL BE MONDAY AND MONDAY NIGHT. 00Z NAM STILL ON TARGET FOR WIDESPREAD RAINFALL IN EXCESS OF ONE INCH FOR THE CWFA DURING THAT TIME FRAME. PREV DISCUSSION... /ISSUED 622 PM CDT SUN OCT 5 2008/ AVIATION...00Z TAF. ACTIVE 24HR PERIOD FOR THE KGRI AREA AS STRONG UPPER LEVEL LOW PRESSURE EJECTS ONTO THE PLAINS DURING THE LAST HALF OF THE FORECAST PERIOD. STREAM OF MOISTURE WITH THIS SYSTEM IS PLENTIFUL FOR EARLY OCTOBER...AND WE WILL CONTINUE TO SEE A SCATTERED OF SPRINKLES OR SHOWERS EARLY IN THE FORECAST PERIOD. THE MAIN RAIN WILL BE DURING THE MONDAY...WITH PREVAILING TSRA AND MVFR CIGS LIKELY NEARLY ALL DAY. WINDS WILL GRADUALLY BACK AROUND TO THE NORTH/NORTHEAST LATE IN THE DAY. PREV DISCUSSION... /ISSUED 333 PM CDT SUN OCT 5 2008/ SHORT TERM...PAST MORNING UPPER AIR DATA ALONG WITH RECENT WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP UPPER TROUGH MOVING ACROSS THE ROCKIES. EMBEDDED WITHIN THE TROUGH IS A CLOSED CIRCULATION SITTING OVER SOUTHERN COLORADO INTO NORTHERN NEW MEXICO. QUICK EXAMINATION OF REGIONAL SURFACE OBS SHOWS A DEEPENING AREA OF LOW PRESSURE ACROSS EASTERN COLORADO WITH A SECOND LOW SITTING JUST EAST OF THE BLACK HILLS REGION. BETWEEN THESE TWO LOWS A WEAK FRONT/DRYLINE IS SHOWN STRETCHING ACROSS THE NEBRASKA PANHANDLE INTO NORTHEAST COLORADO. AHEAD OF THE FRONT...DEEP BOUNDARY LAYER MOISTURE HAS BEEN ADVECTED BACK INTO THE REGION WITH DEWPOINTS IN THE MID 50S TO LOWER 60S SEEN ACROSS THE AREA. DESPITE THIS DEEPER MOISTURE...LAPS AND RUC ANALYSIS DATA SHOW LITTLE TO NO INSTABILITY FROM 600MB DOWN TO THE SURFACE ACROSS THE AREA. NONETHELESS...A BAND OF LIGHT TO MODERATE RAINFALL IS SEEN STRETCHING FROM THE TEXAS PANHANDLE...ACROSS NORTH CENTRAL KANSAS AND INTO THE UPPER MIDWEST. WHILE THE PRECIP OVER THE TEXAS PANHANDLE IS THE RESULT OF DEEP CONVECTION FIRING FURTHER SOUTH ACROSS WEST TEXAS...THE MAINTENANCE OF THIS PRECIP BAND FURTHER NORTH APPEARS TO BE THE RESULT OF A BAND OF MID LEVEL FRONTOGENESIS PRODUCED BY THE LATENT HEAT RELEASE COMING FROM THIS PRECIP AND/OR MID LEVEL VORTICITY ADVECTION. AS THE DAY GIVES WAY TO THE EVENING TO OVERNIGHT HOURS ACROSS THE REGION...THE AFOREMENTIONED CLOSED LOW IS SHOWN TO TRACK EASTWARD INTO THE PLAINS. AT LEAST FOR THIS EVENING...THE MID LEVEL DEFORMATION AND RESULTANT FRONTOGENESIS FROM THIS LOW SHOULD STAY FAR ENOUGH WEST TO BE A NON FACTOR FOR THE FORECAST AREA. GENERALLY THIS WILL LEAVE THE CWA UNDER THE INFLUENCE OF THE LIGHT PRECIP BAND OUT AHEAD OF THE MAIN SYSTEM...BUT RAINFALL AMOUNTS SHOULD BE LIGHT. HOWEVER...STRONGER CONVECTION DEVELOPING CLOSER TO THE FRONT/DRYLINE WHERE SOME MARGINAL INSTABILITY EXISTS ACROSS THE HIGH PLAINS...MAY BEGIN TO SNEAK INTO THE AREA BY MID EVENING. THE CONVECTION ITSELF WILL WEAKEN CONSIDERABLY...BUT LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. THE CHANCE FOR PRECIP WILL THEN BEGIN TO PICK UP LATE TONIGHT INTO EARLY ON MONDAY AS THE UPPER LOW BEGINS TO ENTER THE REGION. A BROAD AREA OF MID LEVEL DEFORMATION AND RESULTANT FRONTOGENESIS WILL SPREAD INTO THE AREA AND ALONG WITH THE REMNANTS OF DEEP CONVECTION SLIDING ACROSS THE SOUTHERN PLAINS WILL PRODUCE WIDESPREAD PRECIPITATION ACROSS THE AREA WITH EMBEDDED THUNDERSTORMS IMPACTING THE AREA AS WELL. CHANCES LOOK HIGH ENOUGH THAT CATEGORICAL POPS WILL REMAIN IN THE FORECAST. EXPECT RAINFALL TO BE HEAVY ENOUGH TO RESULT IN SOME AREAS SEEING RAINFALL TOTALS OF 2 TO 3 INCHES BY LATE SUNDAY NIGHT. IN TERMS OF MONDAY NIGHT...THE MODELS ARE NOW SLOWING DOWN THE MOVEMENT OF THE UPPER LOW WITH A HEALTHY BAND OF MID LEVEL FRONTOGENESIS STILL SEEN ACROSS THE CWA IN THE 700-600MB LAYER. EXPECT THIS TO ALLOW THE MAIN PRECIP BAND TO CONTINUE IMPACTING THE AREA INTO THE EVENING TO EARLY OVERNIGHT HOURS. BASED ON THIS SETUP...HAVE OPTED TO INCREASE POPS INTO THE CATEGORICAL RANGE OVER MOST OF THE CWA DURING THE EVENING AND IN THE EASTERN THIRD OF THE CWA AFTER MIDNIGHT. RAINFALL AMOUNTS WILL REMAIN MODERATE TO HEAVY AT TIMES WITHIN THIS BAND BUT ANY FLOODING ISSUES SHOULD REMAIN AT THE NUISANCE LEVEL. LONG TERM...12Z TUESDAY THROUGH SUNDAY. PRIMARY FORECAST CHALLENGE CONCERNS EVOLUTION OF SYSTEM TO AFFECT THE AREA LATE WEEK INTO THE WEEKEND. BY TUESDAY MORNING...FIRST SYSTEM WILL BE EXITING THE AREA WITH PRECIPITATION MOVING OFF TO THE EAST. KEPT A SMALL POP FOR AREAS EAST OF HWY 281 IN THE MORNING IN CASE SYSTEM IS A LITTLE SLOWER TO PUSH OUT...BUT THE MAIN EVENT WILL BE OVER BY THIS TIME. STRONG SUBSIDENCE IN WAKE OF THE EXITING UPPER TROUGH WILL BRING SHARPLY CLEARING SKIES FROM WEST TO EAST. TEMPERATURES WILL REBOUND ON TUESDAY UNDER INCREASED INSOLATION...BUT STILL BE A TOUCH ON THE COOL SIDE WITH COOLER AIRMASS IN PLACE AND A NORTH/NORTHWEST WIND. A FAST-MOVING UPPER WAVE SKIRTING ALONG THE US/CANADIAN BORDER SENDS A COLD FRONT SOUTH INTO THE AREA ON WEDNESDAY. A DRY AIRMASS WILL BE IN PLACE IN WAKE OF PREVIOUS SYSTEM...AND THUS FRONT LOOKS TO BE MOISTURE STARVED AS IT MOVES IN AND NOT EXPECTING ANY PRECIP TO ACCOMPANY IT. THE FRONT MOVING IN DURING THE DAY WILL PRODUCE A NORTHWEST TO SOUTHEAST GRADIENT IN TEMPS. SOUTHEAST AREAS SHOULD CONTINUE TO REBOUND AHEAD OF THE FRONT/S ARRIVAL. OF COURSE TEMPS WILL DEPEND HEAVILY ON FRONTAL TIMING...BUT WILL AIM HIGHS IN THE UPPER 60S NORTHWEST TO LOWER/MID 70S SOUTHEAST. THE SURFACE BOUNDARY IS EXPECTED TO STALL ACROSS KANSAS...BEFORE EVENTUALLY LIFTING BACK NORTH THROUGH THE CWA AS A WARM FRONT FRIDAY/FRIDAY NIGHT. HAVE KEPT THINGS DRY THROUGH THURSDAY NIGHT...ALTHOUGH HAVE SOME CONCERNS THAT NORTHERN PORTIONS OF THE CWA COULD GET CLIPPED BY SOME PRECIP ESPECIALLY THURSDAY NIGHT BUT POSSIBLY EVEN AS EARLY AS DURING THE DAY ON THURSDAY ASSOCIATED WITH A BAND OF MID-LEVEL /H7-H5/ FRONTOGENESIS THAT SETS UP FROM ROUGHLY UT TO SOUTHERN MN ASSOCIATED WITH A STRONG UPPER JET STREAK ORIENTED ACROSS THE NORTH CENTRAL CONUS. BETTER FOCUS AT THIS POINT LOOKS TO BE JUST NORTH OF THE CWA...BUT WILL NEED TO KEEP A CLOSE EYE ON THIS AND PERHAPS INCREASE POPS IN SUBSEQUENT FORECASTS. FORECAST UNCERTAINTY THEN RAMPS UP GREATLY FRIDAY INTO THE WEEKEND. SIGNIFICANT MODEL DIFFERENCES CONTINUE CONCERNING HANDLING OF NEXT SYSTEM...LEADING TO LOW FORECAST CONFIDENCE. GFS CONTINUES TO LOOK TOO PROGRESSIVE WITH THE SYSTEM...WHILE THE ECMWF REMAINS MUCH SLOWER AS IT DIGS A DEEP CUTOFF OVER THE WESTERN CONUS. HPC PREFERENCE LEANED TOWARD A SOLUTION IN BETWEEN THE TWO SIMILAR TO THE ECMWF ENSEMBLE TIMING...AND GENERALLY FOLLOWED ALONG THOSE SAME LINES. HAVE SMALL PRECIP CHANCES BEGINNING FRIDAY AS WARM FRONT BEGINS TO LIFT NORTHWARD THROUGH THE AREA AND H85 THETA-E ADVECTION INCREASES. CONTINUED WITH SMALL PRECIP CHANCES SATURDAY INTO SUNDAY GIVEN CONTINUED THETA-E ADVECTION AHEAD OF FRONTAL PASSAGE...AND THEN THE FRONT EVENTUALLY COMING THROUGH. COULD EVEN HAVE SOME TROPICAL MOISTURE WORKING IN BY LATE IN THE WEEKEND FROM REMNANTS OF NORBERT. TIMING OF FRONTAL PASSAGE REMAINS HIGHLY UP IN THE AIR...BUT STILL LOOKS LIKE POTENTIAL FOR A SHOT OF CHILLY AIR COMING IN BEHIND THE FRONT ONCE IT FINALLY COMES THROUGH. AT THIS POINT...UNFORTUNATELY CAN/T SAY MUCH MORE THAN IT COULD VERY WELL BE THE COLDEST AIR WE/VE SEEN SO FAR THIS SEASON AND POTENTIALLY THE FIRST FREEZE FOR THE AREA ARRIVING ANYWHERE FROM SATURDAY NIGHT TO MONDAY NIGHT. BUT ONCE AGAIN...STILL A LOT TO BE DETERMINED AND CONFIDENCE AT THIS JUNCTURE IS TOWARD THE BOTTOM END OF THE SPECTRUM. KB && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE HASTINGS NE 927 PM CDT SUN OCT 5 2008 .UPDATE...JUST A SHORT COMMENT REGARDING PRECIPITATION. CWFA HAS STRUGGLED WITH RAINFALL DEVELOPMENT...ALTHOUGH THERE HAS BEEN A BIT MORE IN THE LAST 30 MINUTES OR SO OVER THE WESTERN/NORTHERN CWFA. OPTED TO LOWER PRECIPITATION COVERAGE IN THE NEXT FEW HOURS AS A LARGE PART OF THE CWFA WILL EXPERINCE ONLY VERY LIGHT SHOWERS. BY FAR...THE MAIN RAIN EVENT WILL BE MONDAY AND MONDAY NIGHT. 00Z NAM STILL ON TARGET FOR WIDSPREAD RAINFALL IN EXCESS OF ONE INCH FOR THE CWFA DURING THAT TIME FRAME. && .PREV DISCUSSION... /ISSUED 622 PM CDT SUN OCT 5 2008/ AVIATION...00Z TAF. ACTIVE 24HR PERIOD FOR THE KGRI AREA AS STRONG UPPER LEVEL LOW PRESSURE EJECTS ONTO THE PLAINS DURING THE LAST HALF OF THE FORECAST PERIOD. STREAM OF MOISTURE WITH THIS SYSTEM IS PLENTIFUL FOR EARLY OCTOBER...AND WE WILL CONTINUE TO SEE A SCATTERED OF SPRINKLES OR SHOWERS EARLY IN THE FORECAST PERIOD. THE MAIN RAIN WILL BE DURING THE MONDAY...WITH PREVAILING TSRA AND MVFR CIGS LIKELY NEARLY ALL DAY. WINDS WILL GRADUALLY BACK AROUND TO THE NORTH/NORTHEAST LATE IN THE DAY. PREV DISCUSSION... /ISSUED 333 PM CDT SUN OCT 5 2008/ SHORT TERM...PAST MORNING UPPER AIR DATA ALONG WITH RECENT WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP UPPER TROUGH MOVING ACROSS THE ROCKIES. EMBEDDED WITHIN THE TROUGH IS A CLOSED CIRCULATION SITTING OVER SOUTHERN COLORADO INTO NORTHERN NEW MEXICO. QUICK EXAMINATION OF REGIONAL SURFACE OBS SHOWS A DEEPENING AREA OF LOW PRESSURE ACROSS EASTERN COLORADO WITH A SECOND LOW SITTING JUST EAST OF THE BLACK HILLS REGION. BETWEEN THESE TWO LOWS A WEAK FRONT/DRYLINE IS SHOWN STRETCHING ACROSS THE NEBRASKA PANHANDLE INTO NORTHEAST COLORADO. AHEAD OF THE FRONT...DEEP BOUNDARY LAYER MOISTURE HAS BEEN ADVECTED BACK INTO THE REGION WITH DEWPOINTS IN THE MID 50S TO LOWER 60S SEEN ACROSS THE AREA. DESPITE THIS DEEPER MOISTURE...LAPS AND RUC ANALYSIS DATA SHOW LITTLE TO NO INSTABILITY FROM 600MB DOWN TO THE SURFACE ACROSS THE AREA. NONETHELESS...A BAND OF LIGHT TO MODERATE RAINFALL IS SEEN STRETCHING FROM THE TEXAS PANHANDLE...ACROSS NORTH CENTRAL KANSAS AND INTO THE UPPER MIDWEST. WHILE THE PRECIP OVER THE TEXAS PANHANDLE IS THE RESULT OF DEEP CONVECTION FIRING FURTHER SOUTH ACROSS WEST TEXAS...THE MAINTENANCE OF THIS PRECIP BAND FURTHER NORTH APPEARS TO BE THE RESULT OF A BAND OF MID LEVEL FRONTOGENESIS PRODUCED BY THE LATENT HEAT RELEASE COMING FROM THIS PRECIP AND/OR MID LEVEL VORTICITY ADVECTION. AS THE DAY GIVES WAY TO THE EVENING TO OVERNIGHT HOURS ACROSS THE REGION...THE AFOREMENTIONED CLOSED LOW IS SHOWN TO TRACK EASTWARD INTO THE PLAINS. AT LEAST FOR THIS EVENING...THE MID LEVEL DEFORMATION AND RESULTANT FRONTOGENESIS FROM THIS LOW SHOULD STAY FAR ENOUGH WEST TO BE A NON FACTOR FOR THE FORECAST AREA. GENERALLY THIS WILL LEAVE THE CWA UNDER THE INFLUENCE OF THE LIGHT PRECIP BAND OUT AHEAD OF THE MAIN SYSTEM...BUT RAINFALL AMOUNTS SHOULD BE LIGHT. HOWEVER...STRONGER CONVECTION DEVELOPING CLOSER TO THE FRONT/DRYLINE WHERE SOME MARGINAL INSTABILITY EXISTS ACROSS THE HIGH PLAINS...MAY BEGIN TO SNEAK INTO THE AREA BY MID EVENING. THE CONVECTION ITSELF WILL WEAKEN CONSIDERABLY...BUT LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. THE CHANCE FOR PRECIP WILL THEN BEGIN TO PICK UP LATE TONIGHT INTO EARLY ON MONDAY AS THE UPPER LOW BEGINS TO ENTER THE REGION. A BROAD AREA OF MID LEVEL DEFORMATION AND RESULTANT FRONTOGENESIS WILL SPREAD INTO THE AREA AND ALONG WITH THE REMNANTS OF DEEP CONVECTION SLIDING ACROSS THE SOUTHERN PLAINS WILL PRODUCE WIDESPREAD PRECIPITATION ACROSS THE AREA WITH EMBEDDED THUNDERSTORMS IMPACTING THE AREA AS WELL. CHANCES LOOK HIGH ENOUGH THAT CATEGORICAL POPS WILL REMAIN IN THE FORECAST. EXPECT RAINFALL TO BE HEAVY ENOUGH TO RESULT IN SOME AREAS SEEING RAINFALL TOTALS OF 2 TO 3 INCHES BY LATE SUNDAY NIGHT. IN TERMS OF MONDAY NIGHT...THE MODELS ARE NOW SLOWING DOWN THE MOVEMENT OF THE UPPER LOW WITH A HEALTHY BAND OF MID LEVEL FRONTOGENESIS STILL SEEN ACROSS THE CWA IN THE 700-600MB LAYER. EXPECT THIS TO ALLOW THE MAIN PRECIP BAND TO CONTINUE IMPACTING THE AREA INTO THE EVENING TO EARLY OVERNIGHT HOURS. BASED ON THIS SETUP...HAVE OPTED TO INCREASE POPS INTO THE CATEGORICAL RANGE OVER MOST OF THE CWA DURING THE EVENING AND IN THE EASTERN THIRD OF THE CWA AFTER MIDNIGHT. RAINFALL AMOUNTS WILL REMAIN MODERATE TO HEAVY AT TIMES WITHIN THIS BAND BUT ANY FLOODING ISSUES SHOULD REMAIN AT THE NUISANCE LEVEL. LONG TERM...12Z TUESDAY THROUGH SUNDAY. PRIMARY FORECAST CHALLENGE CONCERNS EVOLUTION OF SYSTEM TO AFFECT THE AREA LATE WEEK INTO THE WEEKEND. BY TUESDAY MORNING...FIRST SYSTEM WILL BE EXITING THE AREA WITH PRECIPITATION MOVING OFF TO THE EAST. KEPT A SMALL POP FOR AREAS EAST OF HWY 281 IN THE MORNING IN CASE SYSTEM IS A LITTLE SLOWER TO PUSH OUT...BUT THE MAIN EVENT WILL BE OVER BY THIS TIME. STRONG SUBSIDENCE IN WAKE OF THE EXITING UPPER TROUGH WILL BRING SHARPLY CLEARING SKIES FROM WEST TO EAST. TEMPERATURES WILL REBOUND ON TUESDAY UNDER INCREASED INSOLATION...BUT STILL BE A TOUCH ON THE COOL SIDE WITH COOLER AIRMASS IN PLACE AND A NORTH/NORTHWEST WIND. A FAST-MOVING UPPER WAVE SKIRTING ALONG THE US/CANADIAN BORDER SENDS A COLD FRONT SOUTH INTO THE AREA ON WEDNESDAY. A DRY AIRMASS WILL BE IN PLACE IN WAKE OF PREVIOUS SYSTEM...AND THUS FRONT LOOKS TO BE MOISTURE STARVED AS IT MOVES IN AND NOT EXPECTING ANY PRECIP TO ACCOMPANY IT. THE FRONT MOVING IN DURING THE DAY WILL PRODUCE A NORTHWEST TO SOUTHEAST GRADIENT IN TEMPS. SOUTHEAST AREAS SHOULD CONTINUE TO REBOUND AHEAD OF THE FRONT/S ARRIVAL. OF COURSE TEMPS WILL DEPEND HEAVILY ON FRONTAL TIMING...BUT WILL AIM HIGHS IN THE UPPER 60S NORTHWEST TO LOWER/MID 70S SOUTHEAST. THE SURFACE BOUNDARY IS EXPECTED TO STALL ACROSS KANSAS...BEFORE EVENTUALLY LIFTING BACK NORTH THROUGH THE CWA AS A WARM FRONT FRIDAY/FRIDAY NIGHT. HAVE KEPT THINGS DRY THROUGH THURSDAY NIGHT...ALTHOUGH HAVE SOME CONCERNS THAT NORTHERN PORTIONS OF THE CWA COULD GET CLIPPED BY SOME PRECIP ESPECIALLY THURSDAY NIGHT BUT POSSIBLY EVEN AS EARLY AS DURING THE DAY ON THURSDAY ASSOCIATED WITH A BAND OF MID-LEVEL /H7-H5/ FRONTOGENESIS THAT SETS UP FROM ROUGHLY UT TO SOUTHERN MN ASSOCIATED WITH A STRONG UPPER JET STREAK ORIENTED ACROSS THE NORTH CENTRAL CONUS. BETTER FOCUS AT THIS POINT LOOKS TO BE JUST NORTH OF THE CWA...BUT WILL NEED TO KEEP A CLOSE EYE ON THIS AND PERHAPS INCREASE POPS IN SUBSEQUENT FORECASTS. FORECAST UNCERTAINTY THEN RAMPS UP GREATLY FRIDAY INTO THE WEEKEND. SIGNIFICANT MODEL DIFFERENCES CONTINUE CONCERNING HANDLING OF NEXT SYSTEM...LEADING TO LOW FORECAST CONFIDENCE. GFS CONTINUES TO LOOK TOO PROGRESSIVE WITH THE SYSTEM...WHILE THE ECMWF REMAINS MUCH SLOWER AS IT DIGS A DEEP CUTOFF OVER THE WESTERN CONUS. HPC PREFERENCE LEANED TOWARD A SOLUTION IN BETWEEN THE TWO SIMILAR TO THE ECMWF ENSEMBLE TIMING...AND GENERALLY FOLLOWED ALONG THOSE SAME LINES. HAVE SMALL PRECIP CHANCES BEGINNING FRIDAY AS WARM FRONT BEGINS TO LIFT NORTHWARD THROUGH THE AREA AND H85 THETA-E ADVECTION INCREASES. CONTINUED WITH SMALL PRECIP CHANCES SATURDAY INTO SUNDAY GIVEN CONTINUED THETA-E ADVECTION AHEAD OF FRONTAL PASSAGE...AND THEN THE FRONT EVENTUALLY COMING THROUGH. COULD EVEN HAVE SOME TROPICAL MOISTURE WORKING IN BY LATE IN THE WEEKEND FROM REMNANTS OF NORBERT. TIMING OF FRONTAL PASSAGE REMAINS HIGHLY UP IN THE AIR...BUT STILL LOOKS LIKE POTENTIAL FOR A SHOT OF CHILLY AIR COMING IN BEHIND THE FRONT ONCE IT FINALLY COMES THROUGH. AT THIS POINT...UNFORTUNATELY CAN/T SAY MUCH MORE THAN IT COULD VERY WELL BE THE COLDEST AIR WE/VE SEEN SO FAR THIS SEASON AND POTENTIALLY THE FIRST FREEZE FOR THE AREA ARRIVING ANYWHERE FROM SATURDAY NIGHT TO MONDAY NIGHT. BUT ONCE AGAIN...STILL A LOT TO BE DETERMINED AND CONFIDENCE AT THIS JUNCTURE IS TOWARD THE BOTTOM END OF THE SPECTRUM. KB && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 622 PM CDT SUN OCT 5 2008 .AVIATION...00Z TAF. ACTIVE 24HR PERIOD FOR THE KGRI AREA AS STRONG UPPER LEVEL LOW PRESSURE EJECTS ONTO THE PLAINS DURING THE LAST HALF OF THE FORECAST PERIOD. STREAM OF MOISTURE WITH THIS SYSTEM IS PLENTIFUL FOR EARLY OCTOBER...AND WE WILL CONTINUE TO SEE A SCATTERED OF SPRINKLES OR SHOWERS EARLY IN THE FORECAST PERIOD. THE MAIN RAIN WILL BE DURING THE MONDAY...WITH PREVAILING TSRA AND MVFR CIGS LIKELY NEARLY ALL DAY. WINDS WILL GRADUALLY BACK AROUND TO THE NORTH/NORTHEAST LATE IN THE DAY. && .PREV DISCUSSION... /ISSUED 333 PM CDT SUN OCT 5 2008/ SHORT TERM...PAST MORNING UPPER AIR DATA ALONG WITH RECENT WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP UPPER TROUGH MOVING ACROSS THE ROCKIES. EMBEDDED WITHIN THE TROUGH IS A CLOSED CIRCULATION SITTING OVER SOUTHERN COLORADO INTO NORTHERN NEW MEXICO. QUICK EXAMINATION OF REGIONAL SURFACE OBS SHOWS A DEEPENING AREA OF LOW PRESSURE ACROSS EASTERN COLORADO WITH A SECOND LOW SITTING JUST EAST OF THE BLACK HILLS REGION. BETWEEN THESE TWO LOWS A WEAK FRONT/DRYLINE IS SHOWN STRETCHING ACROSS THE NEBRASKA PANHANDLE INTO NORTHEAST COLORADO. AHEAD OF THE FRONT...DEEP BOUNDARY LAYER MOISTURE HAS BEEN ADVECTED BACK INTO THE REGION WITH DEWPOINTS IN THE MID 50S TO LOWER 60S SEEN ACROSS THE AREA. DESPITE THIS DEEPER MOISTURE...LAPS AND RUC ANALYSIS DATA SHOW LITTLE TO NO INSTABILITY FROM 600MB DOWN TO THE SURFACE ACROSS THE AREA. NONETHELESS...A BAND OF LIGHT TO MODERATE RAINFALL IS SEEN STRETCHING FROM THE TEXAS PANHANDLE...ACROSS NORTH CENTRAL KANSAS AND INTO THE UPPER MIDWEST. WHILE THE PRECIP OVER THE TEXAS PANHANDLE IS THE RESULT OF DEEP CONVECTION FIRING FURTHER SOUTH ACROSS WEST TEXAS...THE MAINTENANCE OF THIS PRECIP BAND FURTHER NORTH APPEARS TO BE THE RESULT OF A BAND OF MID LEVEL FRONTOGENESIS PRODUCED BY THE LATENT HEAT RELEASE COMING FROM THIS PRECIP AND/OR MID LEVEL VORTICITY ADVECTION. AS THE DAY GIVES WAY TO THE EVENING TO OVERNIGHT HOURS ACROSS THE REGION...THE AFOREMENTIONED CLOSED LOW IS SHOWN TO TRACK EASTWARD INTO THE PLAINS. AT LEAST FOR THIS EVENING...THE MID LEVEL DEFORMATION AND RESULTANT FRONTOGENESIS FROM THIS LOW SHOULD STAY FAR ENOUGH WEST TO BE A NON FACTOR FOR THE FORECAST AREA. GENERALLY THIS WILL LEAVE THE CWA UNDER THE INFLUENCE OF THE LIGHT PRECIP BAND OUT AHEAD OF THE MAIN SYSTEM...BUT RAINFALL AMOUNTS SHOULD BE LIGHT. HOWEVER...STRONGER CONVECTION DEVELOPING CLOSER TO THE FRONT/DRYLINE WHERE SOME MARGINAL INSTABILITY EXISTS ACROSS THE HIGH PLAINS...MAY BEGIN TO SNEAK INTO THE AREA BY MID EVENING. THE CONVECTION ITSELF WILL WEAKEN CONSIDERABLY...BUT LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. THE CHANCE FOR PRECIP WILL THEN BEGIN TO PICK UP LATE TONIGHT INTO EARLY ON MONDAY AS THE UPPER LOW BEGINS TO ENTER THE REGION. A BROAD AREA OF MID LEVEL DEFORMATION AND RESULTANT FRONTOGENESIS WILL SPREAD INTO THE AREA AND ALONG WITH THE REMNANTS OF DEEP CONVECTION SLIDING ACROSS THE SOUTHERN PLAINS WILL PRODUCE WIDESPREAD PRECIPITATION ACROSS THE AREA WITH EMBEDDED THUNDERSTORMS IMPACTING THE AREA AS WELL. CHANCES LOOK HIGH ENOUGH THAT CATEGORICAL POPS WILL REMAIN IN THE FORECAST. EXPECT RAINFALL TO BE HEAVY ENOUGH TO RESULT IN SOME AREAS SEEING RAINFALL TOTALS OF 2 TO 3 INCHES BY LATE SUNDAY NIGHT. IN TERMS OF MONDAY NIGHT...THE MODELS ARE NOW SLOWING DOWN THE MOVEMENT OF THE UPPER LOW WITH A HEALTHY BAND OF MID LEVEL FRONTOGENESIS STILL SEEN ACROSS THE CWA IN THE 700-600MB LAYER. EXPECT THIS TO ALLOW THE MAIN PRECIP BAND TO CONTINUE IMPACTING THE AREA INTO THE EVENING TO EARLY OVERNIGHT HOURS. BASED ON THIS SETUP...HAVE OPTED TO INCREASE POPS INTO THE CATEGORICAL RANGE OVER MOST OF THE CWA DURING THE EVENING AND IN THE EASTERN THIRD OF THE CWA AFTER MIDNIGHT. RAINFALL AMOUNTS WILL REMAIN MODERATE TO HEAVY AT TIMES WITHIN THIS BAND BUT ANY FLOODING ISSUES SHOULD REMAIN AT THE NUISANCE LEVEL. LONG TERM...12Z TUESDAY THROUGH SUNDAY. PRIMARY FORECAST CHALLENGE CONCERNS EVOLUTION OF SYSTEM TO AFFECT THE AREA LATE WEEK INTO THE WEEKEND. BY TUESDAY MORNING...FIRST SYSTEM WILL BE EXITING THE AREA WITH PRECIPITATION MOVING OFF TO THE EAST. KEPT A SMALL POP FOR AREAS EAST OF HWY 281 IN THE MORNING IN CASE SYSTEM IS A LITTLE SLOWER TO PUSH OUT...BUT THE MAIN EVENT WILL BE OVER BY THIS TIME. STRONG SUBSIDENCE IN WAKE OF THE EXITING UPPER TROUGH WILL BRING SHARPLY CLEARING SKIES FROM WEST TO EAST. TEMPERATURES WILL REBOUND ON TUESDAY UNDER INCREASED INSOLATION...BUT STILL BE A TOUCH ON THE COOL SIDE WITH COOLER AIRMASS IN PLACE AND A NORTH/NORTHWEST WIND. A FAST-MOVING UPPER WAVE SKIRTING ALONG THE US/CANADIAN BORDER SENDS A COLD FRONT SOUTH INTO THE AREA ON WEDNESDAY. A DRY AIRMASS WILL BE IN PLACE IN WAKE OF PREVIOUS SYSTEM...AND THUS FRONT LOOKS TO BE MOISTURE STARVED AS IT MOVES IN AND NOT EXPECTING ANY PRECIP TO ACCOMPANY IT. THE FRONT MOVING IN DURING THE DAY WILL PRODUCE A NORTHWEST TO SOUTHEAST GRADIENT IN TEMPS. SOUTHEAST AREAS SHOULD CONTINUE TO REBOUND AHEAD OF THE FRONT/S ARRIVAL. OF COURSE TEMPS WILL DEPEND HEAVILY ON FRONTAL TIMING...BUT WILL AIM HIGHS IN THE UPPER 60S NORTHWEST TO LOWER/MID 70S SOUTHEAST. THE SURFACE BOUNDARY IS EXPECTED TO STALL ACROSS KANSAS...BEFORE EVENTUALLY LIFTING BACK NORTH THROUGH THE CWA AS A WARM FRONT FRIDAY/FRIDAY NIGHT. HAVE KEPT THINGS DRY THROUGH THURSDAY NIGHT...ALTHOUGH HAVE SOME CONCERNS THAT NORTHERN PORTIONS OF THE CWA COULD GET CLIPPED BY SOME PRECIP ESPECIALLY THURSDAY NIGHT BUT POSSIBLY EVEN AS EARLY AS DURING THE DAY ON THURSDAY ASSOCIATED WITH A BAND OF MID-LEVEL /H7-H5/ FRONTOGENESIS THAT SETS UP FROM ROUGHLY UT TO SOUTHERN MN ASSOCIATED WITH A STRONG UPPER JET STREAK ORIENTED ACROSS THE NORTH CENTRAL CONUS. BETTER FOCUS AT THIS POINT LOOKS TO BE JUST NORTH OF THE CWA...BUT WILL NEED TO KEEP A CLOSE EYE ON THIS AND PERHAPS INCREASE POPS IN SUBSEQUENT FORECASTS. FORECAST UNCERTAINTY THEN RAMPS UP GREATLY FRIDAY INTO THE WEEKEND. SIGNIFICANT MODEL DIFFERENCES CONTINUE CONCERNING HANDLING OF NEXT SYSTEM...LEADING TO LOW FORECAST CONFIDENCE. GFS CONTINUES TO LOOK TOO PROGRESSIVE WITH THE SYSTEM...WHILE THE ECMWF REMAINS MUCH SLOWER AS IT DIGS A DEEP CUTOFF OVER THE WESTERN CONUS. HPC PREFERENCE LEANED TOWARD A SOLUTION IN BETWEEN THE TWO SIMILAR TO THE ECMWF ENSEMBLE TIMING...AND GENERALLY FOLLOWED ALONG THOSE SAME LINES. HAVE SMALL PRECIP CHANCES BEGINNING FRIDAY AS WARM FRONT BEGINS TO LIFT NORTHWARD THROUGH THE AREA AND H85 THETA-E ADVECTION INCREASES. CONTINUED WITH SMALL PRECIP CHANCES SATURDAY INTO SUNDAY GIVEN CONTINUED THETA-E ADVECTION AHEAD OF FRONTAL PASSAGE...AND THEN THE FRONT EVENTUALLY COMING THROUGH. COULD EVEN HAVE SOME TROPICAL MOISTURE WORKING IN BY LATE IN THE WEEKEND FROM REMNANTS OF NORBERT. TIMING OF FRONTAL PASSAGE REMAINS HIGHLY UP IN THE AIR...BUT STILL LOOKS LIKE POTENTIAL FOR A SHOT OF CHILLY AIR COMING IN BEHIND THE FRONT ONCE IT FINALLY COMES THROUGH. AT THIS POINT...UNFORTUNATELY CAN/T SAY MUCH MORE THAN IT COULD VERY WELL BE THE COLDEST AIR WE/VE SEEN SO FAR THIS SEASON AND POTENTIALLY THE FIRST FREEZE FOR THE AREA ARRIVING ANYWHERE FROM SATURDAY NIGHT TO MONDAY NIGHT. BUT ONCE AGAIN...STILL A LOT TO BE DETERMINED AND CONFIDENCE AT THIS JUNCTURE IS TOWARD THE BOTTOM END OF THE SPECTRUM. KB && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE HASTINGS NE 333 PM CDT SUN OCT 5 2008 .SHORT TERM...PAST MORNING UPPER AIR DATA ALONG WITH RECENT WATER VAPOR IMAGERY CONTINUES TO SHOW A DEEP UPPER TROUGH MOVING ACROSS THE ROCKIES. EMBEDDED WITHIN THE TROUGH IS A CLOSED CIRCULATION SITTING OVER SOUTHERN COLORADO INTO NORTHERN NEW MEXICO. QUICK EXAMINATION OF REGIONAL SURFACE OBS SHOWS A DEEPENING AREA OF LOW PRESSURE ACROSS EASTERN COLORADO WITH A SECOND LOW SITTING JUST EAST OF THE BLACK HILLS REGION. BETWEEN THESE TWO LOWS A WEAK FRONT/DRYLINE IS SHOWN STRETCHING ACROSS THE NEBRASKA PANHANDLE INTO NORTHEAST COLORADO. AHEAD OF THE FRONT...DEEP BOUNDARY LAYER MOISTURE HAS BEEN ADVECTED BACK INTO THE REGION WITH DEWPOINTS IN THE MID 50S TO LOWER 60S SEEN ACROSS THE AREA. DESPITE THIS DEEPER MOISTURE...LAPS AND RUC ANALYSIS DATA SHOW LITTLE TO NO INSTABILITY FROM 600MB DOWN TO THE SURFACE ACROSS THE AREA. NONETHELESS...A BAND OF LIGHT TO MODERATE RAINFALL IS SEEN STRETCHING FROM THE TEXAS PANHANDLE...ACROSS NORTH CENTRAL KANSAS AND INTO THE UPPER MIDWEST. WHILE THE PRECIP OVER THE TEXAS PANHANDLE IS THE RESULT OF DEEP CONVECTION FIRING FURTHER SOUTH ACROSS WEST TEXAS...THE MAINTENANCE OF THIS PRECIP BAND FURTHER NORTH APPEARS TO BE THE RESULT OF A BAND OF MID LEVEL FRONTOGENESIS PRODUCED BY THE LATENT HEAT RELEASE COMING FROM THIS PRECIP AND/OR MID LEVEL VORTICITY ADVECTION. AS THE DAY GIVES WAY TO THE EVENING TO OVERNIGHT HOURS ACROSS THE REGION...THE AFOREMENTIONED CLOSED LOW IS SHOWN TO TRACK EASTWARD INTO THE PLAINS. AT LEAST FOR THIS EVENING...THE MID LEVEL DEFORMATION AND RESULTANT FRONTOGENESIS FROM THIS LOW SHOULD STAY FAR ENOUGH WEST TO BE A NON FACTOR FOR THE FORECAST AREA. GENERALLY THIS WILL LEAVE THE CWA UNDER THE INFLUENCE OF THE LIGHT PRECIP BAND OUT AHEAD OF THE MAIN SYSTEM...BUT RAINFALL AMOUNTS SHOULD BE LIGHT. HOWEVER...STRONGER CONVECTION DEVELOPING CLOSER TO THE FRONT/DRYLINE WHERE SOME MARGINAL INSTABILITY EXISTS ACROSS THE HIGH PLAINS...MAY BEGIN TO SNEAK INTO THE AREA BY MID EVENING. THE CONVECTION ITSELF WILL WEAKEN CONSIDERABLY...BUT LOCALLY HEAVY RAINFALL WILL BE POSSIBLE. THE CHANCE FOR PRECIP WILL THEN BEGIN TO PICK UP LATE TONIGHT INTO EARLY ON MONDAY AS THE UPPER LOW BEGINS TO ENTER THE REGION. A BROAD AREA OF MID LEVEL DEFORMATION AND RESULTANT FRONTOGENESIS WILL SPREAD INTO THE AREA AND ALONG WITH THE REMNANTS OF DEEP CONVECTION SLIDING ACROSS THE SOUTHERN PLAINS WILL PRODUCE WIDESPREAD PRECIPITATION ACROSS THE AREA WITH EMBEDDED THUNDERSTORMS IMPACTING THE AREA AS WELL. CHANCES LOOK HIGH ENOUGH THAT CATEGORICAL POPS WILL REMAIN IN THE FORECAST. EXPECT RAINFALL TO BE HEAVY ENOUGH TO RESULT IN SOME AREAS SEEING RAINFALL TOTALS OF 2 TO 3 INCHES BY LATE SUNDAY NIGHT. IN TERMS OF MONDAY NIGHT...THE MODELS ARE NOW SLOWING DOWN THE MOVEMENT OF THE UPPER LOW WITH A HEALTHY BAND OF MID LEVEL FRONTOGENESIS STILL SEEN ACROSS THE CWA IN THE 700-600MB LAYER. EXPECT THIS TO ALLOW THE MAIN PRECIP BAND TO CONTINUE IMPACTING THE AREA INTO THE EVENING TO EARLY OVERNIGHT HOURS. BASED ON THIS SETUP...HAVE OPTED TO INCREASE POPS INTO THE CATEGORICAL RANGE OVER MOST OF THE CWA DURING THE EVENING AND IN THE EASTERN THIRD OF THE CWA AFTER MIDNIGHT. RAINFALL AMOUNTS WILL REMAIN MODERATE TO HEAVY AT TIMES WITHIN THIS BAND BUT ANY FLOODING ISSUES SHOULD REMAIN AT THE NUISANCE LEVEL. .LONG TERM...12Z TUESDAY THROUGH SUNDAY. PRIMARY FORECAST CHALLENGE CONCERNS EVOLUTION OF SYSTEM TO AFFECT THE AREA LATE WEEK INTO THE WEEKEND. BY TUESDAY MORNING...FIRST SYSTEM WILL BE EXITING THE AREA WITH PRECIPITATION MOVING OFF TO THE EAST. KEPT A SMALL POP FOR AREAS EAST OF HWY 281 IN THE MORNING IN CASE SYSTEM IS A LITTLE SLOWER TO PUSH OUT...BUT THE MAIN EVENT WILL BE OVER BY THIS TIME. STRONG SUBSIDENCE IN WAKE OF THE EXITING UPPER TROUGH WILL BRING SHARPLY CLEARING SKIES FROM WEST TO EAST. TEMPERATURES WILL REBOUND ON TUESDAY UNDER INCREASED INSOLATION...BUT STILL BE A TOUCH ON THE COOL SIDE WITH COOLER AIRMASS IN PLACE AND A NORTH/NORTHWEST WIND. A FAST-MOVING UPPER WAVE SKIRTING ALONG THE US/CANADIAN BORDER SENDS A COLD FRONT SOUTH INTO THE AREA ON WEDNESDAY. A DRY AIRMASS WILL BE IN PLACE IN WAKE OF PREVIOUS SYSTEM...AND THUS FRONT LOOKS TO BE MOISTURE STARVED AS IT MOVES IN AND NOT EXPECTING ANY PRECIP TO ACCOMPANY IT. THE FRONT MOVING IN DURING THE DAY WILL PRODUCE A NORTHWEST TO SOUTHEAST GRADIENT IN TEMPS. SOUTHEAST AREAS SHOULD CONTINUE TO REBOUND AHEAD OF THE FRONT/S ARRIVAL. OF COURSE TEMPS WILL DEPEND HEAVILY ON FRONTAL TIMING...BUT WILL AIM HIGHS IN THE UPPER 60S NORTHWEST TO LOWER/MID 70S SOUTHEAST. THE SURFACE BOUNDARY IS EXPECTED TO STALL ACROSS KANSAS...BEFORE EVENTUALLY LIFTING BACK NORTH THROUGH THE CWA AS A WARM FRONT FRIDAY/FRIDAY NIGHT. HAVE KEPT THINGS DRY THROUGH THURSDAY NIGHT...ALTHOUGH HAVE SOME CONCERNS THAT NORTHERN PORTIONS OF THE CWA COULD GET CLIPPED BY SOME PRECIP ESPECIALLY THURSDAY NIGHT BUT POSSIBLY EVEN AS EARLY AS DURING THE DAY ON THURSDAY ASSOCIATED WITH A BAND OF MID-LEVEL /H7-H5/ FRONTOGENESIS THAT SETS UP FROM ROUGHLY UT TO SOUTHERN MN ASSOCIATED WITH A STRONG UPPER JET STREAK ORIENTED ACROSS THE NORTH CENTRAL CONUS. BETTER FOCUS AT THIS POINT LOOKS TO BE JUST NORTH OF THE CWA...BUT WILL NEED TO KEEP A CLOSE EYE ON THIS AND PERHAPS INCREASE POPS IN SUBSEQUENT FORECASTS. FORECAST UNCERTAINTY THEN RAMPS UP GREATLY FRIDAY INTO THE WEEKEND. SIGNIFICANT MODEL DIFFERENCES CONTINUE CONCERNING HANDLING OF NEXT SYSTEM...LEADING TO LOW FORECAST CONFIDENCE. GFS CONTINUES TO LOOK TOO PROGRESSIVE WITH THE SYSTEM...WHILE THE ECMWF REMAINS MUCH SLOWER AS IT DIGS A DEEP CUTOFF OVER THE WESTERN CONUS. HPC PREFERENCE LEANED TOWARD A SOLUTION IN BETWEEN THE TWO SIMILAR TO THE ECMWF ENSEMBLE TIMING...AND GENERALLY FOLLOWED ALONG THOSE SAME LINES. HAVE SMALL PRECIP CHANCES BEGINNING FRIDAY AS WARM FRONT BEGINS TO LIFT NORTHWARD THROUGH THE AREA AND H85 THETA-E ADVECTION INCREASES. CONTINUED WITH SMALL PRECIP CHANCES SATURDAY INTO SUNDAY GIVEN CONTINUED THETA-E ADVECTION AHEAD OF FRONTAL PASSAGE...AND THEN THE FRONT EVENTUALLY COMING THROUGH. COULD EVEN HAVE SOME TROPICAL MOISTURE WORKING IN BY LATE IN THE WEEKEND FROM REMNANTS OF NORBERT. TIMING OF FRONTAL PASSAGE REMAINS HIGHLY UP IN THE AIR...BUT STILL LOOKS LIKE POTENTIAL FOR A SHOT OF CHILLY AIR COMING IN BEHIND THE FRONT ONCE IT FINALLY COMES THROUGH. AT THIS POINT...UNFORTUNATELY CAN/T SAY MUCH MORE THAN IT COULD VERY WELL BE THE COLDEST AIR WE/VE SEEN SO FAR THIS SEASON AND POTENTIALLY THE FIRST FREEZE FOR THE AREA ARRIVING ANYWHERE FROM SATURDAY NIGHT TO MONDAY NIGHT. BUT ONCE AGAIN...STILL A LOT TO BE DETERMINED AND CONFIDENCE AT THIS JUNCTURE IS TOWARD THE BOTTOM END OF THE SPECTRUM. KB && .AVIATION...18Z KGRI TAF. VFR CONDITIONS WILL STILL PREVAIL THROUGH THE MAJORITY OF THIS TAF PERIOD...AS A LARGE UPPER LEVEL LOW PRESSURE SYSTEM CONTINUES TO SLOWLY APPROACH. ALTHOUGH A FEW LIGHT RAIN SHOWERS WILL BE IN THE AREA THIS AFTERNOON AND EVENING...THE MAIN CONCERN INITIALLY WILL BE STOUT SOUTH BREEZES GUSTING TO AROUND 30 KTS AT TIMES THROUGH EARLY EVENING. THERE IS STILL PLENTY OF UNCERTAINTY REGARDING THE ONSET OF STEADIER RAINFALL AT KGRI...BUT FOR NOW HAVE KEPT PRECIPITATION AND MVFR CEILING/VISIBILITY OUT OF THE PREVAILING FORECAST UNTIL AT LEAST 12Z. THIS MAY END UP BEING TOO AGGRESSIVE AND HAVE TO BE DELAYED EVEN FURTHER IN FUTURE FORECASTS...AS IT NOW APPEARS THAT THE BULK OF RAIN AND MVFR/POSSIBLE IFR CONDITIONS SHOULD HOLD OFF UNTIL MONDAY AFTERNOON AND EVENING. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ ne AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 738 PM EDT MON OCT 6 2008 .SYNOPSIS... A COLD UPPER LEVEL TROUGH WILL SHIFT SOUTHEAST OFF THE NEW ENGLAND COAST TONIGHT RESULTING IN DIMINISHING CLOUD COVER ACROSS THE NORTH COUNTRY THIS EVENING. A STRONG AREA OF HIGH PRESSURE WILL BUILD IN BEHIND THIS SYSTEM...FROM NORTH OF LAKE HURON TO SOUTHEAST ONTARIO INTO CENTRAL NEW YORK STATE BY EARLY TUESDAY MORNING. THIS WILL RESULT IN IDEAL RADIATIONAL COOLING CONDITIONS TONIGHT WITH MUCH OF THE NORTH COUNTRY AT OR BELOW FREEZING FOR EARLY MORNING LOWS ON TUESDAY...WITH AREAS OF FROST EXPECTED. THE REGION OF HIGH PRESSURE WILL BRING FAIR WEATHER CONDITIONS THROUGH WEDNESDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... AS OF 343 PM EDT MONDAY...STEEP LOW-LEVEL LAPSE RATES AND SHALLOW INSTABILITY RESULTED IN WIDESPREAD DAYTIME CUMULUS CLOUDS TODAY...AND ISOLATED RAIN SHOWER ACTIVITY ACROSS CENTRAL VT. PER LATEST RUC ANALYSIS...THE CORE OF COLDEST 500MB TEMPERATURES /-28 TO -30C/ IS ALREADY SHIFTING EASTWARD ACROSS NH AND SRN ME. THIS COMBINED WITH THE LOSS OF INSOLATIONAL HEATING WILL RESULT IN A RAPID DECREASE IN CUMULUS CLOUDS THIS EVENING...WITH SKIES BECOME MOSTLY CLEAR AREAWIDE BY 1-2Z. WITH SFC HIGH PRESSURE CENTERED BETWEEN LAKE HURON AND JAMES BAY THIS AFTERNOON...A NLY GRADIENT FLOW WILL CONTINUE INTO THIS EVENING...UNTIL PBL FULLY DECOUPLES. IN THE FORECAST...HAVE MAINTAINED MENTION OF NW WINDS AROUND 10 MPH THROUGH THIS EVENING. THE WIDER VALLEYS AND HIGHER ELEVATIONS WILL SEE THESE WINDS DIMINISH LATER IN THE EVENING...WHILE THE SHELTERED VALLEYS WILL SEE WINDS BECOME NEARLY CALM SHORTLY AFTER SUNSET TONIGHT. WITH THE DIMINISHING CLOUD COVER...SFC DEWPOINTS ALREADY IN THE LOWER 30S...AND HIGH PRESSURE BUILDING TOWARD THE REGION...CONDITIONS WILL BECOME FAVORABLE FOR RADIATIONAL COOLING FROM LATE THIS EVENING ONWARD THROUGH THE REMAINDER OF THE OVERNIGHT HOURS. WE CONTINUE TO EXPECT WIDESPREAD FROST FORMATION...EXCEPT VERY NEAR THE LAKE CHAMPLAIN SHORELINE. MOST SECTIONS WILL FALL BELOW FREEZING TONIGHT...WITH LOWS VERY NEAR 32F AT BTV TONIGHT. THE SARANAC LAKE AIRPORT WILL LIKELY SEE A LOW TEMP NEAR 20F TONIGHT...WITH READINGS IN THE LOW TO MID 20S IN FAR NERN VT WHERE WINDS WILL STAY IN THE 5-10 MPH THROUGH MOST OF THE EVENING /OWING TO STRONGER LOW-LEVEL GRADIENT FLOW/. HAVE MAINTAINED PREVIOUS FROST/FREEZE HEADLINES /PLEASE SEE LATEST STATEMENT...ALBNPWBTV/...EXCEPT DECIDED TO UPGRADE WINDSOR COUNTY VERMONT FROM A FROST ADVISORY TO A FREEZE WARNING...BASED ON EXPECTED LOW TEMPERATURES 29-32F ACROSS MUCH OF THE COUNTY. THE ONLY AREAS EXCLUDED FROM THE ADVISORY/WARNING AREAS ARE ACROSS THE NORTHERN ADIRONDACKS AND CALEDONIA/ESSEX COUNTIES IN NERN VT WHERE A WIDESPREAD FREEZE OCCURRED ON THE MORNING OF SEPTEMBER 19TH. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... AS OF 350 PM EDT MONDAY...A DEEP-TROPOSPHERIC RIDGE AXIS IN PLACE ACROSS THE NORTH COUNTRY WILL BRING A TRANQUIL STRETCH OF WEATHER TUESDAY THROUGH EARLY WEDNESDAY NIGHT...WITH NO PRECIPITATION EXPECTED. ANOTHER COLD NIGHT IS EXPECTED TUESDAY NIGHT...WITH LOW TEMPERATURES IN A SIMILAR RANGE TO THOSE EXPECTED TONIGHT /MOST OF THE FORECAST AREA WILL SEE MIN TEMPS AT OR BELOW 32F/. SKIES WILL BE MOSTLY CLEAR THROUGH MUCH OF THE PERIOD...EXCEPT FOR INCREASING CLOUDS FROM WEST TO EAST DURING WEDNESDAY NIGHT. A WEAKENING FRONTAL SYSTEM APPROACHES LATE WEDNESDAY NIGHT AND HAVE INCLUDED A CHANCE OF SHOWERS FOR THIS FEATURE. AT THIS POINT...MOST PRECIPITATION AMOUNTS THROUGH 12Z THURSDAY SHOULD BE AOB A TENTH OF AN INCH. && .LONG TERM /THURSDAY THROUGH MONDAY/... AS OF 300 PM EDT MONDAY...ABOVE NORMAL TEMPERATURES TO AFFECT THE AREA FROM THURSDAY THROUGH SUNDAY. WAA WILL STREAM INTO THE AREA AHEAD OF APPROACHING WEAK COLD FRONT ON THURSDAY. LIMITED MOISTURE WITH THIS FEATURE...AND BEST DYNAMICS WILL REMAIN WELL TO OUR NORTH...SO HAVE ONLY INCLUDED CHANCE FOR SHOWERS DURING THURSDAY. A SURFACE RIDGE WILL BUILD IN BEHIND THE FRONT ON FRIDAY...AND ANOTHER LOW PRESSURE SYSTEM WILL FORM OVER THE CAROLINAS. FORMATION OF THIS LOW HAS ACTUALLY BEEN PRETTY PERSISTENT IN THE GFS MODEL RUNS OVER THE PAST TWO DAYS. THERE IS A POSSIBILITY FOR THE MOISTURE ASSOCIATED WITH THIS LOW TO GET CAUGHT UP IN THE FLOW AND STREAM ACROSS THE NORTHEAST FOR SATURDAY THROUGH SUNDAY. AT THIS TIME HAVE JUST INCLUDED CHANCE POPS BECAUSE OF A LACK OF MODEL TO MODEL CONSISTENCY. HOPEFULLY SOON THE MODELS WILL COME TOGETHER A BIT MORE FOR DAYS 4 THROUGH 8 BECAUSE THE LAST FEW DAYS HAVE BEEN LOW CONFIDENCE FORECASTS...AS IS TODAY. ANOTHER LOW PRESSURE SYSTEM WILL PASS WELL TO OUR NORTH ON SUNDAY...BRINGING WEAK COLD FRONT ACROSS THE REGION. HAVE AGAIN MENTIONED VERY LOW CHANCE POPS. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... THROUGH 00Z WEDNESDAY...MAINLY VFR THROUGH THE FIRST 24 HOURS WITH SCATTERED IFR OR BELOW IN PATCHY FOG AFTER MIDNIGHT. CLEAR SKIES AND LIGHT WINDS WILL PREVAIL TONIGHT AND TUESDAY. THIS WILL ALLOW FOG TO DEVELOP AT THE USUAL SITES. KMPV WILL DROP TO VLIFR AFTER 03Z AND REMAIN SO THROUGH 14Z. OPTED TO LEAVE OUT MENTION OF FREEZING FOG AT KMPV AS TEMPERATURES WILL BE BORDERLINE. IF IT DOES DROP BELOW FREEZING AT KMPV...IT SHOULD ONLY BE FOR A FEW HOURS. KRUT WILL SEE VISIBILITY AROUND 4SM AFTER 06Z...WITH OFF AND ON VLIFR 08Z-12Z. KSLK SHOULD REMAIN VFR WITH OCCASIONAL IFR POSSIBLE 07Z-11Z. BOTH THE WRF AND GFS HINT AT POSSIBLE EAST WINDS LATE TONIGHT AT KBTV...WHICH IS USUALLY FAVORABLE FOR ADVECTION FOG. HOWEVER...AIRMASS WILL BE VERY DRY AND MET MOS KEEPS WINDS NORTHWEST. THIS WOULD PRECLUDE ANY VISIBILITY OBSTRUCTIONS DUE TO FOG AT KBTV. GIVEN THE UNCERTAINTY...THIS WILL BEAR WATCHING TONIGHT. 00Z WEDNESDAY THROUGH SATURDAY...VFR TO CONTINUE THROUGH WEDNESDAY NIGHT AS HIGH PRESSURE AT THE SURFACE AND ALOFT REMAIN THE DOMINANT FEATURE ACROSS THE NORTH COUNTRY. IFR CAN BE EXPECTED EARLY WEDNESDAY MORNING AT THE USUAL SITES DUE TO FOG. A WEAKENING COLD FRONT WILL SLIP ACROSS THE FORECAST AREA THURSDAY BRINGING THE CHANCE FOR LIGHT RAIN SHOWERS TO ALL TAF SITES. GIVEN THE LACK OF MOISTURE WITH THIS SYSTEM...CONDITIONS SHOULD REMAIN VFR/MVFR. HIGH PRESSURE AND FAIR WEATHER WILL RETURN BY FRIDAY MORNING...THEN MORE RAIN SATURDAY AS LOW PRESSURE SLIDES BY TO THE SOUTH. MVFR WITH PERHAPS SCATTERED IFR FOR THE WEEKEND SYSTEM. NOTICE TO USERS OF TERMINAL AERODROME FORECASTS (TAF)...BEGINNING AT 0000 UTC ON NOVEMBER 5...2008...THE FORMAT FOR TAFS WILL CHANGE. THE NATIONAL WEATHER SERVICE WILL BEGIN TO ISSUE TAFS USING A VALID DATE AND TIME GROUP IN THE FORECAST. ALL METEOROLOGICAL AGENCIES WORLDWIDE WILL ALSO ISSUE THEIR TAF FORECASTS IN THIS NEW FORMAT. THIS IS BEING DONE TO ACCOMMODATE 30 HOUR TAF FORECASTS THAT WILL BE DONE FOR SELECT MAJOR INTERNATIONAL AIRPORTS WORLDWIDE. THERE WILL BE 32 MAJOR U.S. INTERNATIONAL AIRPORTS FOR WHICH TAFS FORECASTS WILL BE VALID FOR 30 HOURS. THIS FORMAT CHANGE IS BEING MANDATED BY THE INTERNATIONAL CIVIL AVIATION ORGANIZATION (ICAO). THE 6 TAF FORECASTS BEING DONE BY THE NATIONAL WEATHER SERVICE IN BURLINGTON WILL CONTINUE TO BE VALID FOR 24 HOURS. TO SEE EXAMPLES OF THIS NEW FORMAT...PLEASE GO TO THE INTERNET WEB SITE LISTED BELOW. WWW.AVIATIONWEATHER.GOV/NOTICE/TAF30.PHP (ALL LOWER CASE) && .BTV WATCHES/WARNINGS/ADVISORIES... VT...FREEZE WARNING FROM 1 AM TO 8 AM EDT TUESDAY FOR VTZ003-006- 008-010-012-016>019. FROST ADVISORY FROM 1 AM TO 8 AM EDT TUESDAY FOR VTZ001-002- 005-009-011. NY...FREEZE WARNING FROM 1 AM TO 8 AM EDT TUESDAY FOR NYZ026-027- 087. FROST ADVISORY FROM 1 AM TO 8 AM EDT TUESDAY FOR NYZ028-035. && $$ SYNOPSIS...BANACOS NEAR TERM...BANACOS SHORT TERM...BANACOS LONG TERM...NEILES AVIATION...MB ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 312 PM EDT MON OCT 6 2008 .SYNOPSIS... A TROUGH OF LOW PRESSURE WILL MOVE THROUGH THE REGION THIS MORNING...FOLLOWED BY A STRONG RIDGE OF HIGH PRESSURE...WHICH WILL BE IN CONTROL OF THE WEATHER OVER THE AREA INTO THURSDAY. A COUPLE OF WEATHER SYSTEMS WILL THEN AFFECT THE REGION THURSDAY NIGHT RIGHT THROUGH NEXT WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 933 AM EDT MONDAY...A MID-LVL VORTICITY AXIS SHIFTING SOUTHEAST ACROSS THE SOUTHERN HALF OF THE FORECAST AREA PER IR IMAGERY AND LATEST RUC ANALYSIS. THIS FEATURE CONTINUES TO BE ASSOCIATED WITH SCATTERED TO BROKEN CLOUDS...WHICH WILL LIKELY LINGER THRU THE REMAINDER OF THIS MORNING. ONCE THE VORT AXIS SHIFTS FURTHER SE...MID-LEVEL AVA WILL CONTRIBUTE TO SUBSIDENCE AND DIMINISHING CLOUDS THIS AFTERNOON WITH MOSTLY SUNNY CONDITIONS ANTICIPATED. AT THE SFC...1035MB ANTICYCLONE CENTERED SOUTH OF JAMES BAY WILL BUILD SLOWLY SEWD...WITH THE RIDGE AXIS REACHING SERN ONTARIO/CENTRAL NY BY 12Z TUESDAY. A NORTHERLY LOW-LEVEL FLOW WILL DEVELOP ACROSS THE FORECAST AREA AS AIR MASS MIXES OUT LATE THIS MORNING AND THROUGH THE AFTERNOON HRS. LOOKING AT 10M WINDS AROUND 10 KTS WITH OCCASIONAL GUSTS 15-18 KTS ACROSS THE REGION. WINDS WILL DIMINISH LATE THIS EVENING AND ESTABLISH GOOD RADIATIONAL COOLING CONDITIONS ACROSS THE NORTH COUNTRY. MOST SECTIONS WILL GO AOB 32F FOR LOWS...EXCEPT NEAR THE LAKE CHAMPLAIN SHORELINE/CHAMPLAIN ISLANDS. WE WILL MAINTAIN FROST AND FREEZE HEADLINES AS THEY CURRENTLY EXIST...AS CURRENT FORECAST LOOKS ON TRACK. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... AS OF 415 AM EDT MONDAY...A COUPLE NICE DAYS ON TAP FOR TUES AND WED...AS SFC HIGH DRIFTS SLOWLY OFF THE EAST COAST. EXPECTING AN INCR IN HIGHS FROM TUES INTO WED AS WINDS WILL SHIFT TO MORE WSW BY WED. HAVE GONE A COUPLE DEGREES ABV GUIDNACE FOR WEDNESDAY W/ 850 TEMPS NEARING +8C TO +10C. && .LONG TERM /THURSDAY THROUGH SUNDAY/... AS OF 300 PM EDT MONDAY...ABOVE NORMAL TEMPERATURES TO AFFECT THE AREA FROM THURSDAY THROUGH SUNDAY. WAA WILL STREAM INTO THE AREA AHEAD OF APPROACHING WEAK COLD FRONT ON THURSDAY. LIMITED MOISTURE WITH THIS FEATURE...AND BEST DYNAMICS WILL REMAIN WELL TO OUR NORTH...SO HAVE ONLY INCLUDED CHANCE FOR SHOWERS DURING THURSDAY. A SURFACE RIDGE WILL BUILD IN BEHIND THE FRONT ON FRIDAY...AND ANOTHER LOW PRESSURE SYSTEM WILL FORM OVER THE CAROLINAS. FORMATION OF THIS LOW HAS ACTUALLY BEEN PRETTY PERSISTENT IN THE GFS MODEL RUNS OVER THE PAST TWO DAYS. THERE IS A POSSIBILITY FOR THE MOISTURE ASSOCIATED WITH THIS LOW TO GET CAUGHT UP IN THE FLOW AND STREAM ACROSS THE NORTHEAST FOR SATURDAY THROUGH SUNDAY. AT THIS TIME HAVE JUST INCLUDED CHANCE POPS BECAUSE OF A LACK OF MODEL TO MODEL CONSISTENCY. HOPEFULLY SOON THE MODELS WILL COME TOGETHER A BIT MORE FOR DAYS 4 THROUGH 8 BECAUSE THE LAST FEW DAYS HAVE BEEN LOW CONFIDENCE FORECASTS...AS IS TODAY. ANOTHER LOW PRESSURE SYSTEM WILL PASS WELL TO OUR NORTH ON SUNDAY...BRINGING WEAK COLD FRONT ACROSS THE REGION. HAVE AGAIN MENTIONED VERY LOW CHANCE POPS. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... THROUGH 18Z TUESDAY...BKN TO SCT CLOUD COVER ACROSS THE CWA THIS AFTERNOON WILL BECOME CLEAR BY ABOUT 00Z...THEN REMAIN CLEAR THROUGH WEDNESDAY. UPPER LEVEL TROF WILL PUSH EAST OF THE REGION THIS EVENING AND SURFACE HIGH PRESSURE DROPS SOUTH OUT OF CANADA AND RIDGES INTO THE REGION. WINDS ARE CURRENTLY OUT OF THE NNW 10 TO 15 KTS AND GUSTING...BUT WILL BECOME LIGHT AND VARIABLE AFTER 00Z. HAVE INCLUDED BR/FG AT MPV AND RUT WITH A PRETTY DECENT RADIATIONAL FOG NIGHT COMING UP. ANY FOG THAT DOES FORM WILL LIFT BY 12Z AND HAVE INDICATED THIS IN THE TAFS. TOMORROW THERE WILL BE CLEAR SKIES AND LIGHT WINDS AS HIGH PRESSURE CONTINUES TO BUILD. 18Z TUESDAY THROUGH FRIDAY...HIGH PRESSURE WILL BE OVER THE REGION THROUGH WEDNESDAY. VFR CONDITIONS...EXCEPT LOCAL IFR/LIFR IN RADIATION FOG 06Z-14Z WEDNESDAY IN SHELTERED VLYS...INCLUDING TAF SITES MPV/SLK. A WEAK FRONTAL SYSTEM WILL BRING A CHANCE OF SHOWERS LATE WED NITE/THURS...BUT CIGS/VSBYS MAINLY VFR. DRY WX AND VFR CONDITIONS EXPECTED FRIDAY. NOTICE TO USERS OF TERMINAL AERODROME FORECASTS (TAF)...BEGINNING AT 0000 UTC ON NOVEMBER 5...2008...THE FORMAT FOR TAFS WILL CHANGE. THE NATIONAL WEATHER SERVICE WILL BEGIN TO ISSUE TAFS USING A VALID DATE AND TIME GROUP IN THE FORECAST. ALL METEOROLOGICAL AGENCIES WORLDWIDE WILL ALSO ISSUE THEIR TAF FORECASTS IN THIS NEW FORMAT. THIS IS BEING DONE TO ACCOMMODATE 30 HOUR TAF FORECASTS THAT WILL BE DONE FOR SELECT MAJOR INTERNATIONAL AIRPORTS WORLDWIDE. THERE WILL BE 32 MAJOR U.S. INTERNATIONAL AIRPORTS FOR WHICH TAFS FORECASTS WILL BE VALID FOR 30 HOURS. THIS FORMAT CHANGE IS BEING MANDATED BY THE INTERNATIONAL CIVIL AVIATION ORGANIZATION (ICAO). THE 6 TAF FORECASTS BEING DONE BY THE NATIONAL WEATHER SERVICE IN BURLINGTON WILL CONTINUE TO BE VALID FOR 24 HOURS. TO SEE EXAMPLES OF THIS NEW FORMAT...PLEASE GO TO THE INTERNET WEB SITE LISTED BELOW. WWW.AVIATIONWEATHER.GOV/NOTICE/TAF30.PHP (ALL LOWER CASE) && .BTV WATCHES/WARNINGS/ADVISORIES... VT...FREEZE WARNING FROM 1 AM TO 8 AM EDT TUESDAY FOR VTZ003-006- 008-010-012-016>019. FROST ADVISORY FROM 1 AM TO 8 AM EDT TUESDAY FOR VTZ001-002- 005-009-011. NY...FREEZE WARNING FROM 1 AM TO 8 AM EDT TUESDAY FOR NYZ026-027- 087. FROST ADVISORY FROM 1 AM TO 8 AM EDT TUESDAY FOR NYZ028-035. && $$ SYNOPSIS...JN NEAR TERM...BANACOS SHORT TERM...JN LONG TERM...NEILES AVIATION...NEILES ny AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1033 PM EDT MON OCT 6 2008 .SYNOPSIS... STRONG HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTH TONIGHT... PUSHING A DRY COLD FRONT SOUTHWARD THROUGH THE AREA. COOLER TEMPERATURES ARE EXPECTED BEHIND THE FRONT FOR TUESDAY THROUGH WEDNESDAY. A STORM SYSTEM WILL APPROACH FROM THE WEST AND BRING OUR NEXT CHANCE OF RAIN STARTING WEDNESDAY NIGHT. && .NEAR TERM /THROUGH TUESDAY/... AS OF 1030 PM MONDAY... ...DRY WITH INCREASING CLOUDS AND LOWS IN THE LOWER TO MIDDLE 50S OVERNIGHT... A BACKDOOR FRONT WAS DIFFUSING OVER CENTRAL NC AT 10 PM THIS EVENING. THE COMBINATION OF LOW LEVEL COLD ADVECTION BEHIND THE FRONT... NOCTURNAL COOLING... AND ATLANTIC MOISTURE (SAMPLED IN THE 1500-5000 THSD FT LAYER AT WALLOPS THIS EVENING)... MAY LEAD TO ADEQUATE LOW LEVEL SATURATION TO SUPPORT THE DEVELOPMENT OF SCATTERED TO PERHAPS BROKEN STRATUS OR STRATOCUMULUS ACROSS THE AREA OVERNIGHT. IN FACT... LATEST SATELLITE IMAGERY AND SURFACE OBS INDICATE THESE CLOUDS MAY BE ON THE UPSWING OVER SOUTHEASTERN VA. MEANWHILE... AN INITIALLY SEPARATE AREA OF STRATOCUMULUS HAS DEVELOPED ALONG THE EAST FACING SLOPES OF THE CENTRAL APPALACHIANS. EXPECT THAT SOME OF THIS CLOUD COVER MAY SPILL EASTWARD INTO THE PIEDMONT LATE TONIGHT... IN RESPONSE TO LOW LEVEL WINDS VEERING TO A MORE EASTERLY/UPSLOPE COMPONENT LATE. THE AREAL EXTENT OF THE CLOUD COVER WILL HAVE AN IMPACT ON OVERNIGHT LOW TEMPERATURES... BUT FEEL THAT LOWER TO MIDDLE 50S FROM NORTH TO SOUTH IS STILL ATTAINABLE GIVEN THE LOW LEVEL COLD AIR JUST UPSTREAM OVER VA (CHARACTERIZED BY OBSERVED 1000-850MB THICKNESSES OF 1359 METERS AT BOTH WALLOPS AND STERLING)... WHICH IS POISED TO SPREAD INTO CENTRAL NC LATER TONIGHT. SUSPECT THAT A STEADY LIGHT NORTHEASTERLY BREEZE AND THE ANTICIPATED CLOUD DEVELOPMENT SHOULD LARGELY MITIGATE THE POTENTIAL FOR RADIATION FOG OVERNIGHT... THOUGH SOME SHALLOW PATCHES WILL BE POSSIBLE WHERE CLOUDS ARE SLOWEST TO DEVELOP AND LESS EXPANSIVE... GIVEN THE RESIDUALLY HIGH SURFACE DEWPOINTS IN THE UPPER 50S TO AROUND 60. -MWS TUESDAY: THE MORNING CLOUDS SHOULD BE LAST TO BREAK OVER THE NW CWA GIVEN THE UPSLOPE-DIRECTED LOW LEVEL FLOW... AND HAVE HELD ONTO MOSTLY CLOUDY SKIES THERE THROUGH TUESDAY MORNING. LOW LEVEL THICKNESSES PLUMMET INTO THE 1360-1365 M RANGE BY TOMORROW... WHICH YIELDS HIGHS OF 69-76. -GIH && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... AS OF 300 PM MONDAY... DIFFICULT FORECAST THIS PERIOD WITH NWP GUIDANCE PROVIDING SEVERAL POSSIBLE SOLUTIONS. GUIDANCE IS IN DECENT AGREEMENT ON TUES NIGHT AS SHORT WAVE RIDING BUILDS INTO THE CAROLINAS AS TROUGH DEEPENS ACROSS THE MS VALLEY. SHOULD SEE HIGH CLOUDS INCREASE ON TUES NIGHT WITH LOWS IN THE UPPER 40S ACROSS THE N COASTAL PLAIN AND THE LOWER 50S IN THE WESTERN PIEDMONT. ON WEDNESDAY GUIDANCE BEGINS TO DIVERGE WITH GFS DEPICTING A STRONGER WAVE MOVING ACROSS THE MIDWEST THAT CLOSES OFF EARLY WED WHILE THE ECMWF IS SLOWER AND WEAKER...WAITING UNTIL WED EVE BEFORE CLOSING OFF. 12Z CANADIAN AND NAM-WRF AREA ALSO SLOWER AND A BIT WEAKER WITH THE UPPER LOW. ALL OF THE GUIDANCE SUGGEST THAT BEST FORCING AND MOISTURE SHOULD BE LOCATED OVER CENTRAL NC LATE WED NIGHT AND ESPECIALLY THURS. HAVE ADJUSTED POPS UPWARD AND FOCUSED THEM A LITTLE FURTHER S WITH LIKELY POPS NOW INCLUDED FOR MUCH OF THE CWA. SEVERAL DETAILS ARE WORTH NOTING. THE 12Z GFS IS NOTABLY STRONGER IN THE LOW LEVEL FLOW ESP AT 850 WHERE A SE FLOW REACHES 35 KNOTS ON THURS MORNING. THIS ENHANCED FLOW IS COINCIDENT WITH A BULLSEYE OF PRECIPITATION THAT MOVES OUT OF THE GULF. MODEL GENERATED CONVECTIVE PRECIPITATION IS ONLY RESPONSIBLE FOR AROUND A QUARTER OF THIS PRECIPITATION AREA. HAVE DOWNPLAYED PRECIPITATION AMOUNTS DURING THIS PERIOD AS THIS FEATURE APPEARS ANOMALOUS. NAM SHOWS A SIMILAR FEATURE ALTHOUGH IT IS OF A WEAKER MAGNITUDE. EXPECT TO SEE SOME WEAK IN SITU DAMMING AS PRECIPITATION MOVES INTO A STABLE AIRMASS ACROSS INTERIOR PORTIONS OF THE PIEDMONT. WILL LOWER TEMPS IN CAD FAVORED AREAS ON THURS AND HOLD ONTO CAD FEATURE THROUGH SAT AM. SOME CONCERN EXISTS OVER THE POTENTIAL IMPACT OF UPSTREAM CONVECTION ACROSS THE NORTHERN GULF COAST ON WED INTO THURSDAY. WITH A VARIETY OF SCENARIOS POSSIBLE IT IS DIFFICULT TO CONCLUDE DEFINITIVELY BUT AT LEAST A MODEST ATLANTIC ONSHORE FLOW IS EXPECTED. STUDIES HAVE SHOWN THE ONSHORE FLOW CAN MITIGATE THE IMPACT OF UPSTREAM CONVECTION. WE`VE TRIMMED BACK RAINFALL AMOUNTS AND POPS SLIGHTLY IN THE TRIAD. -BLAES && .LONG TERM /FRIDAY THROUGH MONDAY/... AS OF 300 PM MONDAY... NOT A GREAT DEAL OF CONFIDENCE IN THE EXTENDED FORECAST AS WELL. SENSIBLE WEATHER DETAILS AT THE BEGINNING OF THE EXTENDED PERIOD WILL LARGELY DEPEND ON THE EVOLUTION OF THE UPPER LOW THAT LIFTS ACROSS THE CAROLINAS. THE GFS AND 00Z CANADIAN ARE PROGRESSIVE WITH THE UPPER LOW AND MOVE IT NORTHEAST INTO THE MID ATLANTIC AWAY FROM THE AREA. THE ECMWF AND THE 12Z CANADIAN MOVE THE UPPER LOW SLOWLY SE AND OFF THE GA/SC COAST ON FRI. WHILE THE 00Z UK MOVES THE UPPER LOW PROGRESSIVELY AND OFF THE GA COAST BY THU NIGHT. HPC IS LEANING TOWARD THE ECMWF WHICH WOULD BRING THE BEST CHANCE OF PRECIPITATION ACROSS CENTRAL NC ON WED NIGHT AND THURS. MOISTURE...CLOUDS AND THE THREAT OF PRECIPITATION LINGERS INTO FRIDAY NIGHT. TEMPS ON FRIDAY SHOULD STILL BE MODULATED BY A LINGERING IN SITU DAMMING EVENT. IF ECMWF VERIFIES THEN A LONGER THEN ADVERTISED PERIOD OF CLOUDS AND SHOWERS MAY CONTINUE INTO SATURDAY AND SUNDAY. WITH VARIOUS SCENARIOS IN PLAY WILL OPT TO PLAY UP CLOUDS ON SAT BUT KEEP MENTION OF PRECIPITATION OUT THE FORECAST. HEIGHTS SHOULD BUILD EVENTUALLY AFTER THE SYSTEM DEPARTS WITH SOME CLEARING AND MODERATING TEMPS. -BLAES && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... AS OF 915 PM... THE FORECAST PROBLEM FOR THE TAF PERIOD IS THE POTENTIAL FOR LOW LEVEL STRATUS TOWARD DAWN IN CENTRAL NORTH CAROLINA. AT THE CURRENT TIME SOME STRATUS HAS DEVELOPED IN UPSLOPE FLOW IN THE NORTH CAROLINA FOOTHILLS. TINY AMOUNTS OF STRATUS IN THE COASTAL PLAIN AS WELL WITH A FEW CLOUDS IN THE FAYETTEVILLE VICINITY. GIVEN THE PAST SUCCESS OF THE RUC MODEL IN THESE SITUATIONS A RELATIVELY CEILING FREE NIGHT IS FORECAST. HOWEVER CONFIDENCE IS LOW DUE TO OTHER COMPUTER MODELS INDICATING POSSIBLE STRATUS DEVELOPMENT. CEILINGS BASED FROM 1500 TO 2500 FEET COULD OCCUR...MOST LIKELY AT RDU AND RWI... BUT STRATUS BUILDING EAST FROM THE FOOTHILLS INTO GSO AND INT IS NOT OUT OF THE QUESTION. WILL MONITOR OBSERVATIONS AND MODELS AND ADJUST AS NEEDED. EXPECT VFR CONDITIONS TUESDAY WITH VFR CEILINGS NEAR 4000 FEET AT TIMES DURING THE AFTERNOON. SOME FOG LATE TUESDAY NIGHT INTO EARLY WEDNESDAY MORNING BUT LOW STRATUS CEILINGS OTHER THAN LOCALIZED IS NOT EXPECTED AT THIS TIME. IFR TO LIFR CEILINGS AND VISIBILITIES AT TIMES ACROSS CENTRAL NORTH CAROLINA STARTING AFTER MIDNIGHT WEDNESDAY NIGHT... AND CONTINUING THROUGH MUCH OF THURSDAY AND FRIDAY. VFR CONDITIONS SATURDAY. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...BLAES NEAR TERM...MWS/HARTFIELD SHORT TERM...BLAES LONG TERM...BLAES nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1010 AM EDT MON OCT 6 2008 .SYNOPSIS... STRONG HIGH PRESSURE WILL BEGIN TO BUILD INTO THE REGION FROM THE NORTH TODAY... PUSHING A DRY BACKDOOR COLD FRONT THROUGH THE AREA TONIGHT. MOSTLY CLEAR SKIES AND MUCH COOLER TEMPERATURES ARE EXPECTED BEHIND THE FRONT ON TUESDAY. && .NEAR TERM /THROUGH TONIGHT/... AS OF 1005 AM MONDAY... THE EARLY MORNING FOG HAS MIXED OUT NEARLY EVERYWHERE. THE 12Z SURFACE ANALYSIS SHOWS THE INCOMING FRONTAL ZONE... PROVIDING THE LEADING EDGE OF THE LOWER DEW POINTS... NOW STRETCHING ACROSS CENTRAL VA... ALTHOUGH THE ZONE ITSELF IS RATHER DIFFUSE. LATEST MODEL OUTPUT FROM THE 12KM NAM AND 13KM RUC INDICATE THE FRONT IS UNLIKELY TO MAKE MUCH SOUTHWARD PROGRESS INTO THE CWA PRIOR TO EVENING... SO EXPECT STEADY HEATING TODAY UNENCUMBERED BY CLOUDS (GIVEN THE DEEP ISENTROPIC DOWNGLIDE OVER NC) OR COLD AIR ADVECTION. MORNING THICKNESSES OFF THE 12Z GSO SOUNDING WERE MINIMALLY WARMER THAN YESTERDAY`S... SO HIGHS TODAY SHOULD BE SIMILAR OR A DEGREE OR SO WARMER... AROUND 80-84. -GIH EARLIER DISCUSSION... AS OF 315 AM... SFC ANALYSIS THIS MORNING SHOWED 1032 MB HIGH PRESSURE CENTERED JUST NORTH OF THE GREAT LAKES...WITH A SFC RIDGE AXIS EXTENDING SOUTH INTO THE MID-ATLANTIC AND CAROLINAS. A STATIONARY FRONT WAS LOCATED IN CENTRAL/NORTHERN VA...EXTENDING NORTHWEST THROUGH THE OH VALLEY. ALOFT...A DEEP UPPER TROUGH WAS DIGGING INTO THE MIDWEST...WITH RIDGING ALOFT JUST EAST OF THE MS RIVER...AND ANOTHER DEEP UPPER TROUGH WAS DROPPING SOUTHEAST INTO NEW ENGLAND. TODAY AND TONIGHT: THE DEEP UPPER TROUGH CURRENTLY IN EASTERN CANADA IS PROGGED TO DROP SOUTHEAST THROUGH NEW ENGLAND INTO THE NORTH ATLANTIC THIS AFTERNOON...WITH UPPER RIDGING BUILDING IN BEHIND IN ITS WAKE ACROSS THE OH VALLEY AND GREAT LAKES. THIS PROVIDES AN IDEAL SETUP FOR MASS CONVERGENCE ALOFT OVER THE NORTHERN MID-ATLANTIC AND NEW ENGLAND... ALLOWING SFC HIGH PRESSURE CURRENTLY NORTH OF THE GREAT LAKES TO BUILD SOUTHEAST AND STRENGTHEN OVER PA/NY BY 00Z THIS EVENING...WITH THE SFC RIDGE AXIS STRENGTHENING AND EXTENDING SOUTH THROUGH THE CAROLINAS. THIS STRONG SFC RIDGING WILL PUSH A BACKDOOR COLD FRONT SOUTH THROUGH THE AREA AFTER SUNSET THIS EVENING. EXPECT SUNNY OR MOSTLY SUNNY SKIES THROUGH THE DAY TODAY WITH SYNOPTIC SUBSIDENCE AND LOW RH VALUES THROUGHOUT THE COLUMN. ALTHOUGH THE BACKDOOR COLD FRONTAL PASSAGE TONIGHT IS EXPECTED TO BE DRY (NO PRECIP) GIVEN LIMITED MOISTURE AND ONLY WEAK LOW LEVEL CONVERGENCE...BOTH THE GFS/NAM 1000-850 MB LAYER RH`S INCREASE TO 85-95% IN THE FAR WESTERN PIEDMONT AND FOOTHILLS LATE TONIGHT (AFTER 06Z)...INDICATING THE POSSIBILITY OF LOW STRATUS DEVELOPING IN THOSE AREAS. THE NAM IS ACTUALLY HINTING AT LOW STRATUS DEVELOPING IN SE VA AND NE NC JUST AHEAD OF THE BACKDOOR FRONT AFTER SUNSET...PROPAGATING WEST/WSW THROUGH CENTRAL NC TOWARD THE WESTERN PIEDMONT DURING THE OVERNIGHT HOURS. ALTHOUGH I AM UNSURE OF EXACTLY HOW MUCH CLOUD COVER THERE WILL BE... FEEL CONFIDENT ENOUGH TO SHOW CLOUD COVER INCREASING TO AT LEAST PARTLY CLOUDY OVERNIGHT...WITH POTENTIALLY MOSTLY CLOUDY SKIES IN THE TRIAD BY MORNING. W/REGARD TO HIGH TEMPS...A BLEND OF GFS/NAM THICKNESSES YIELD 1380M INCREASING TO ROUGHLY 1390M THIS AFTERNOON...WHICH WOULD SUPPORT HIGH TEMPS IN THE UPPER 70S BASED ON LOCAL TEMP RESEARCH. HOWEVER... THE MAV/MET MOS GUIDANCE IS IN UNUSUALLY GOOD AGREEMENT SHOWING HIGH TEMPS MAKING IT INTO THE LOWER 80S. AS SUCH...HAVE DECIDED TO TREND TOWARD MOS GUIDANCE...SHOWING HIGHS RANGING FROM 81-83F ACROSS THE AREA. LOW TEMPS TONIGHT WILL BE SOMEWHAT TRICKY SINCE WE WILL LIKELY HAVE SOME LOW CLOUD COVER ASSOC/W THE BACKDOOR FRONT...IN ADDITION TO COLD ADVECTION IN AT LEAST NORTHEAST PORTIONS OF THE AREA BEHIND THE FRONT DURING THE OVERNIGHT HOURS. LOOKING AT MOS GUIDANCE AND UPSTREAM TEMPS/DEWPOINTS...LOW TEMPS RANGING FROM THE LOWER 50S (NE) TO MID 50S ELSEWHERE LOOKS REASONABLE. -VINCENT && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/ AS OF 315 AM MONDAY... TUESDAY AND TUESDAY NIGHT: ALTHOUGH RIDGING ALOFT BUILDS OVER THE EAST COAST DURING THE DAY TUESDAY AS A DEEP TROUGH MOVES EAST INTO THE MIDWEST...THE POST FRONTAL AIRMASS SURGING INTO THE AREA FROM THE NORTH WILL KEEP HIGH TEMPS MUCH COOLER THAN WHAT IS EXPECTED TODAY...WITH THICKNESSES AND MOS GUIDANCE SUGGESTING HIGHS RANGING FROM AROUND 70F NORTH TO 75F SOUTH. WITH SUBSIDENCE ALOFT INCREASING OVER THE AREA AS THE UPPER RIDGE BUILDS OVER THE CAROLINAS...AND SFC RIDGING EXTENDING INTO THE AREA FROM THE NORTH...EXPECT MOSTLY SUNNY OR SUNNY SKIES TUESDAY... EXCEPT PERHAPS DURING THE MORNING HOURS WHEN STRATUS OR STRATO-CU MAY STILL BE HANGING AROUND IN WESTERN AND SOUTHERN PORTIONS OF THE AREA. THROUGHOUT TUESDAY NIGHT THE DEEP UPPER TROUGH IN THE MIDWEST CONTINUES PROGRESSING EAST...REACHING WESTERN TN/KY BY 12Z WED MORNING...WITH THE UPPER RIDGING OVER THE EAST COAST WEAKENING AND BEING FORCED EAST TOWARD THE ATLANTIC. BY 12Z WED MORNING...AN UPPER LOW IS EXPECTED TO DEVELOP WITHIN THE TROUGH ACROSS SOUTHEAST MO OR NORTHEAST AR. WE SHOULD SEE MID/UPPER LEVEL CLOUD COVER BEGINNING TO INCREASE ACROSS WESTERN PORTIONS OF THE STATE BY SUNRISE WED MORNING AS CLOUD COVER PROPAGATES DOWNSTREAM OF CONVECTION IN THE DEEP SOUTH. HOWEVER...MOST OF THE NIGHT SHOULD BE CLOUD FREE ACROSS THE ENTIRE AREA...AND WITH A COOL/DRY AIRMASS IN PLACE...EXPECT SOMEWHAT CHILLY LOWS IN THE MID/UPPER 40S OVER MOST OF THE AREA...WITH LOWER 50S POSSIBLE IN THE FAR WESTERN PIEDMONT IF CLOUD COVER ADVANCES INTO THAT AREA QUICK ENOUGH. WEDNESDAY: EXPECT CLOUD COVER TO INCREASE THROUGHOUT THE DAY WED FROM THE WEST AND SOUTH AS THE UPPER LOW TO OUR WEST BECOMES CUT-OFF FROM THE NORTHERN STREAM JET AND GETS PICKED UP BY THE SOUTHERN STREAM... HEADING EAST ACROSS THE TN VALLEY OR DEEP SOUTH TOWARD THE CAROLINAS. THE LATEST GFS/ECMWF/NAM DIFFER SOMEWHAT IN THE TIMING/POSITION AND STRENGTH OF THE UPPER LOW...ALTHOUGH THEY ALL SHOW THE SAME GENERAL THING...A FAIRLY RESPECTABLE UPPER LEVEL SYSTEM ADVANCING TOWARD THE CAROLINAS. ALTHOUGH PRECIP MAY BEGIN ENTERING FAR WESTERN PORTIONS OF THE STATE AND UPSTATE SC BY SUNSET WED EVENING...DO NOT EXPECT A CHANCE FOR PRECIP ACROSS CENTRAL NC UNTIL AT LEAST WED NIGHT GIVEN THE LATEST MODEL GUIDANCE...AND WILL THEREFORE KEEP THE FCST DRY AT THIS TIME. AFTERNOON TEMPS WILL DEPEND PRIMARILY ON HOW THICK THE ADVANCING MID/UPPER LEVEL CLOUD COVER IS...BUT HIGHS IN THE LOWER/MID 70S LOOK ATTAINABLE LOOKING AT THE LATEST MOS GUIDANCE AND THICKNESSES. WEDNESDAY NIGHT THROUGH THURSDAY NIGHT: ALTHOUGH THERE IS STILL SOME DISAGREEMENT AMONG THE MAJOR OPERATIONAL AND ENSEMBLE MODELS ON THE EXACT DETAILS OF THE UPPER LEVEL SYSTEM APPROACHING THE CAROLINAS...THERE APPEARS TO BE ENOUGH OF A CONSENSUS (THE NAM IS A NOTABLE OUTLIER THOUGH) TO START BRINGING SLIGHT CHANCE POPS TO WEST/SW PORTIONS OF CENTRAL NC AFTER SUNSET WED EVENING...WITH POPS INCREASING FROM SOUTHWEST TO NORTHEAST AFTER MIDNIGHT. WILL SHOW POPS INCREASING TO SLIGHT CHANCE (20%) EVERYWHERE BY SUNRISE THU MORNING...WITH LOW CHANCE (30%) POPS IN THE WESTERN HALF OF THE AREA. WILL INCREASE POPS TO HIGH CHANCE (50%) DURING THE DAY THURSDAY AS THE BULK OF MODEL GUIDANCE SHOWS THE SOUTHERN STREAM UPPER LOW ADVANCING EVER CLOSER TO THE CAROLINAS...WITH PRECIP SPREADING OVER THE ENTIRE AREA FROM WEST TO EAST OR SW TO NE. THE LATEST 00Z ECMWF IS IN AGREEMENT WITH THE 00Z GFS IN SHOWING THIS OCCURRING. IF TODAY`S 12Z MODEL RUNS CONTINUE THE TREND SHOWN IN THE 00Z GFS/ECMWF...WE WILL NEED TO UP POPS TO LIKELY ACROSS THE ENTIRE AREA FROM THURSDAY AFTERNOON THROUGH SUNRISE FRIDAY MORNING. SO BASICALLY...WE COULD SEE WIDESPREAD RAIN DURING THE DAY THURSDAY...CONTINUING THROUGH THURSDAY NIGHT INTO FRIDAY MORNING. ALTHOUGH IT IS TOO EARLY TO GET SPECIFIC WITH RAINFALL AMOUNTS...THE LATEST GFS/ECMWF SUGGEST A WIDESPREAD 1-2" IS NOT OUT OF THE QUESTION. LOW TEMPS ON THU/FRI MORNINGS WILL HIGHLY DEPEND ON THE EXACT POSITION/STRENGTH OF THE SURFACE LOW/FRONTS ASSOC/W THE UPPER LOW...IN ADDITION TO WHERE PRECIP IS OCCURRING...AND AS SUCH ARE DIFFICULT TO DETERMINE AT THIS TIME. BASED ON MOS GUIDANCE AND EXPECTED PROGRESSION OF PRECIP...LOWS IN THE MID 50S LOOK REASONABLE THU MORNING...WITH LOWS RANGING FROM THE MID 50S TO LOWER 60S FRI MORNING. HIGH TEMPS ON THU WILL RANGE FROM THE MID 60S IN THE NW PIEDMONT TO LOWER/MID 70S IN THE SE COASTAL PLAIN. -VINCENT && .LONG TERM /FRIDAY THROUGH SUNDAY/... AS OF 250 AM MONDAY... ONLY MINOR CHANGES TO PREVIOUS FORECAST. PREFER THE PROGRESSIVE TIMING OF THE GFS AND CANADIAN...AS OPPOSE TO THE SLOWER EC...WITH THE NORTHERN EJECTION OF THE SOUTHERN STREAM UPPER CYCLONE AT THE START OF THE PERIOD. THIS CALLS FOR DIMINISHING POPS FRIDAY AND FRIDAY NIGHT. HEIGHTS BUILD ALOFT IN THE WAKE OF THE SYSTEM AND THROUGH THE WEEKEND...AS NW PACIFIC S/W ENERGY AMPLIFIES OVER THE INTERMOUNTAIN REGION. ADDITIONALLY...SOUTHERLY RETURN FLOW FROM OFFSHORE SURFACE ANTICYCLONE WILL SUPPORT TEMPERATURES WELL ABOVE NORMAL......MUCH LIKE THE PAST TWO DAYS WITH AFTERNOON HIGHS IN THE UPPER 70S TO LOWER 80S. -CBL && .AVIATION /12Z MONDAY THROUGH FRIDAY/... AS OF 730 AM MONDAY... LOOK FOR MVFR AND IFR FOG TO QUICKLY BURN THIS MORNING. SOME FAIR WEATHER CU WITH BASES AT OR ABOVE 5000 FEET. A DRY BACK-DOOR COLD FRONT WILL DROP SOUTHWARD THROUGH CENTRAL NORTH CAROLINA TONIGHT. SOME IFR CEILINGS AND VISIBILITIES MONDAY NIGHT THROUGH EARLY TUESDAY MORNING...ESPECIALLY IN THE WEST...WHERE MODEL RH CROSS SECTIONS INDICATE LOW-LEVEL MOISTURE BANKING UP ON THE LEE SIDE OF THE MOUNTAINS...DUE TO THE ENELY FLOW. THE RISK OF RAIN WITH MVFR OR IFR CEILINGS AND VISIBILITIES INCREASES LATE WEDNESDAY NIGHT THROUGH THURSDAY AS A POTENT STORM SYSTEM APPROACHES FROM THE WEST. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...HARTFIELD/VINCENT SHORT TERM...VINCENT LONG TERM...CBL AVIATION...CBL nc AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 953 PM CDT MON OCT 6 2008 .DISCUSSION... 0230Z RADAR IMAGE SHOWING BROAD AREA OF PRECIP MAINLY ALONG AND WEST OF INTERSTATE 29 UP TO FARGO...THEN SOUTHEAST OF A FARGO TO LAKE OF THE WOODS COUNTY LINE. PRECIP MATCHING UP WELL WITH 00Z NAMS NEARLY SATURATED 305K CONDENSATION PRESSURE DEFICITS...WITH HEAVIER RAIN LINING UP NICELY WITH 00Z NAM H700-H850 FRONTOGENESIS BAND. USING A BLEND OF NAM AND RUC FOR EVENING UPDATES. HAVE UPDATED GRIDS FOR CURRENT ORIENTATION OF PRECIP BAND...AND REDUCING POPS IN LINE WITH AFOREMENTIONED PARAMETERS. SECOND ISSUE BEYOND POPS WILL BE SKY COVER BEHIND SFC TROUGH. WV IMAGERY SHOWING RAPID DRYING OVER WESTERN ND...HOWEVER FORWARD PROGRESSION OF CLEARING LINE IS SLOWING DOWN. THUS WILL KEEP THINGS MOSTLY CLOUDY THROUGH AT LEAST 06Z TO 09Z. KEEPING THE MENTION OF PATCHY FOG IN THE GRIDS FOR NOW AS CHANCES OF ANY DECENT RADIATIONAL COOLING TONIGHT ARE MINIMAL...ESPECIALLY ON THE MN SIDE. THUS WILL NOT INTRODUCE DENSE FOG ATTM. && .AVIATION... LOOK FOR VFR CONDS FOR CURRENT AND NEXT SET OF TAFS AT ALL SITES EXCEPT BEMIDJI...WHERE THINGS SHOULD FLUCTUATE BETWEEN MARGINAL AND VFR THROUGHOUT THE NIGHT DUE TO CONTINUATION OF RAIN. COULD SEE SOME FOG DEVELOPMENT AT BJI BY EARLY MORNING AS WELL...BUT WILL NOT DROP VIS TO LOW AS BJI SHOULD REMAIN CLOUDY AND EXPECTING MORE OF A LOWERING STRATUS DECK. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ SPEICHER nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 1038 AM CDT SUN OCT 5 2008 .DISCUSSION... 850 MOIST AND TEMP ADV CONTINUES TO FORCE INCREASING AREAS OF RAIN AND SHOWERS TO SPREAD NORTH. SOME DRYING IN THE LOWER LEVELS MAY INHIBIT RAINFALL IN SOUTHERN VALLEY THIS AFTERNOON. HAVE UPPED POPS AND QPF IN DVL AREA BASED ON 305K ISENTROPIC SURFACE UP-GLIDE AND 88D ECHO INCREASES. LEADING EDGE OF PRECIPITATION ON MINNESOTA SIDE OF RIVER RUNNING INTO RELATIVELY DRY EASTERLY FLOW...BUT EXPECT THIS TO SHIFT SLOWLY EAST AS THE DAY PROGRESSES. REMOVED THUNDER THREAT AS ATMOSPHERE APPEARS STABLE. OVERALL PREVIOUS FORECAST HAS GOOD HANDLE AND CHANGES MINIMAL. && .AVIATION... THICKENING AND INCREASING CLOUD COVER SOUTHWEST TO NORTHEAST THIS AFTERNOON. LOWERING LIKELY TONIGHT INTO MONDAY AS MOISTURE BECOME MORE ABUNDANT IN THE LOWER LEVELS WITH MVFR CIGS PSBL MONDAY...ESP IN THE FARGO AREA. && .PREV DISCUSSION... /ISSUED 322 AM CDT SUN OCT 5 2008/ SHORT TERM... FCST CHALLENGE IS PCPN TIMING AND AMOUNTS. OVERALL PREV FCST LOOKING GOOD AND 00Z MODEL DATA SUPPORTS PREV TIMING WELL. 06Z RUC SHOWING STRONG 850 MB WARM ADV ON NOSE OF 50 KT 850 MB JET OVER SE SD/NW IA AND FINALLY SEEING INCREASE IN THUNDERSTORM ACTIVITY IN THIS AREA. MODELS PROGGED THIS WELL AND HAVE THIS AREA CENTERED OVER SRN MN/NRN IA MUCH OF THE DAY. CLOSER TO HOME...NRN EDGE OF 700 MB WARM ADVECTION PRODUCING SHOWERS AND EVEN ISOLD THUNDERSTORM AT TIMES OVER SE ND INTO WCNTRL MN. QUESTION IS HOW FAR WILL SHOWERS GET INTO THE DRY AIRMASS THAT IS OVER NE ND/NW MN. 06Z RUC DOES SHOW THE INITIAL WARM ADV SURGE RUNNING OUT OF GAS AS IT APPROACHES GFK-BJI AREA BY 12Z...AS ACTIVITY FURTHER SOUTH TAKES OVER. THIS WOULD SEEM REASONABLE....SO KEPT TIGHT POP GRADIENT FROM PREV FCST THRU 18Z SUN IN KEEPING PCPN OUT OF GFK-BJI AREAS UNTIL THIS AFTN. THIS AFTN WILL SEE SECOND SURGE OF 850 MB WARM/MOIST ADVECTION NORTHWARD INTO SE ND...AND THIS WILL OVERSPREAD ALL BUT FAR NRN MN TONIGHT. PWATS INCREASE TO 1.50 INCHES TONIGHT SO LOOKS LIKE GENEROUS COVERAGE OF SHOWERS AND ISOLD THUNDERSTORMS OVER MOST AREAS. NRN STREAM SHORT WAVE MOVING INTO B.C. WILL MOVE EAST AND SWING INTO ND MONDAY HELPING TO KICK SFC TROUGH/LOW PRESSURE EASTWARD INTO THE VALLEY IN THE AFTN/EVE AND INTO MN MON NIGHT/TUES MORNING. GOOD MOISTURE FEED AHD OF SFC TROUGH SHOULD AID IN CONTINUED WIDESRPEAD SHOWER ACTIVITY MONDAY OVER ERN ND AND INTO NW/WCNTRL MN MON NIGHT INTO TUESDAY MORNING. OVERALL STORM TOTALS PCPN WILL AVERAGE 1 TO 1.50 INCHES SE ND INTO WCNTRL MN WITH CLOSE TO AN INCH AVERAGE OVER NE ND/FAR NW MN. LOCALIZED HEAVIER AMTS LIKELY TO NR 2 INCHES. PROLONGED NATURE OF RAIN SHOULD NOT RESULT IN ANY FLOODING ISSUES. ADDED LOW POP FOR SHOWERS ON WEDNESDAY PER COORD WITH WFO BIS DUE TO SHORT WAVE MOVING ALONG CANADIAN BORDER. LONG TERM... DID DECIDE TO UP POPS FRI AND FRI NIGHT FROM 20S TO 30S IN MOST AREAS AS MODELS PRETTY GOOD AGREEMENT THAT PCPN WILL OCCUR. NOW 00Z EMCWF HOWEVER IS A BIT SLOWER AND HAS MORE PCPN LATER ON IN THE WEEKEND. MODELS OVERALL NOT HANDLING STORM SYSTEM FOR LATE IN THE WEEK/WEEKEND WELL OVER THE PAST FEW DAYS BUT ALL AGREE STORMINESS WILL BE THERE. AVIATION... THICKENING AND INCREASING CLOUD COVER SOUTHWEST TO NORTHEAST TODAY...BUT INITIALLY CLOUD BASES WILL BE ABV 7000 FT. SOME LOWERING LIKELY TONIGHT INTO MONDAY AS MOISTURE BECOME MORE ABUNDANT IN THE LOWER LEVELS WITH MVFR CIGS PSBL MONDAY...ESP IN THE FARGO AREA. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ EWENS nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND FORKS ND 322 AM CDT SUN OCT 5 2008 .SHORT TERM... FCST CHALLENGE IS PCPN TIMING AND AMOUNTS. OVERALL PREV FCST LOOKING GOOD AND 00Z MODEL DATA SUPPORTS PREV TIMING WELL. 06Z RUC SHOWING STRONG 850 MB WARM ADV ON NOSE OF 50 KT 850 MB JET OVER SE SD/NW IA AND FINALLY SEEING INCREASE IN THUNDERSTORM ACTIVITY IN THIS AREA. MODELS PROGGED THIS WELL AND HAVE THIS AREA CENTERED OVER SRN MN/NRN IA MUCH OF THE DAY. CLOSER TO HOME...NRN EDGE OF 700 MB WARM ADVECTION PRODUCING SHOWERS AND EVEN ISOLD THUNDERSTORM AT TIMES OVER SE ND INTO WCNTRL MN. QUESTION IS HOW FAR WILL SHOWERS GET INTO THE DRY AIRMASS THAT IS OVER NE ND/NW MN. 06Z RUC DOES SHOW THE INITIAL WARM ADV SURGE RUNNING OUT OF GAS AS IT APPROACHES GFK-BJI AREA BY 12Z...AS ACTIVITY FURTHER SOUTH TAKES OVER. THIS WOULD SEEM REASONABLE....SO KEPT TIGHT POP GRADIENT FROM PREV FCST THRU 18Z SUN IN KEEPING PCPN OUT OF GFK-BJI AREAS UNTIL THIS AFTN. THIS AFTN WILL SEE SECOND SURGE OF 850 MB WARM/MOIST ADVECTION NORTHWARD INTO SE ND...AND THIS WILL OVERSPREAD ALL BUT FAR NRN MN TONIGHT. PWATS INCREASE TO 1.50 INCHES TONIGHT SO LOOKS LIKE GENEROUS COVERAGE OF SHOWERS AND ISOLD THUNDERSTORMS OVER MOST AREAS. NRN STREAM SHORT WAVE MOVING INTO B.C. WILL MOVE EAST AND SWING INTO ND MONDAY HELPING TO KICK SFC TROUGH/LOW PRESSURE EASTWARD INTO THE VALLEY IN THE AFTN/EVE AND INTO MN MON NIGHT/TUES MORNING. GOOD MOISTURE FEED AHD OF SFC TROUGH SHOULD AID IN CONTINUED WIDESRPEAD SHOWER ACTIVITY MONDAY OVER ERN ND AND INTO NW/WCNTRL MN MON NIGHT INTO TUESDAY MORNING. OVERALL STORM TOTALS PCPN WILL AVERAGE 1 TO 1.50 INCHES SE ND INTO WCNTRL MN WITH CLOSE TO AN INCH AVERAGE OVER NE ND/FAR NW MN. LOCALIZED HEAVIER AMTS LIKELY TO NR 2 INCHES. PROLONGED NATURE OF RAIN SHOULD NOT RESULT IN ANY FLOODING ISSUES. ADDED LOW POP FOR SHOWERS ON WEDNESDAY PER COORD WITH WFO BIS DUE TO SHORT WAVE MOVING ALONG CANADIAN BORDER. .LONG TERM... DID DECIDE TO UP POPS FRI AND FRI NIGHT FROM 20S TO 30S IN MOST AREAS AS MODELS PRETTY GOOD AGREEMENT THAT PCPN WILL OCCUR. NOW 00Z EMCWF HOWEVER IS A BIT SLOWER AND HAS MORE PCPN LATER ON IN THE WEEKEND. MODELS OVERALL NOT HANDLING STORM SYSTEM FOR LATE IN THE WEEK/WEEKEND WELL OVER THE PAST FEW DAYS BUT ALL AGREE STORMINESS WILL BE THERE. && .AVIATION... THICKENING AND INCREASING CLOUD COVER SOUTHWEST TO NORTHEAST TODAY...BUT INITIALLY CLOUD BASES WILL BE ABV 7000 FT. SOME LOWERING LIKELY TONIGHT INTO MONDAY AS MOISTURE BECOME MORE ABUNDANT IN THE LOWER LEVELS WITH MVFR CIGS PSBL MONDAY...ESP IN THE FARGO AREA. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...NONE. MN...NONE. && $$ RIDDLE nd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CLEVELAND OH 141 AM EDT SUN OCT 5 2008 .SYNOPSIS... A LARGE AREA OF HIGH PRESSURE FROM HUDSON BAY TO THE GREAT LAKES WILL REMAIN OVER THE AREA THROUGH SUNDAY. ALSO...A WEAK FRONTAL BOUNDARY NEAR THE OHIO RIVER WILL REMAIN STATIONARY THROUGH THE END OF THE WEEKEND. THIS BOUNDARY WILL BEGIN MOVING NORTH SUNDAY NIGHT ALLOWING FOR CLOUDS AND THE CHANCE FOR SHOWERS. THE BOUNDARY WILL GRADUALLY DISSIPATE THROUGH MONDAY AS ANOTHER STRONG HIGH PRESSURE BUILDS SOUTHWARD FROM CANADA. && .NEAR TERM /UNTIL 8 AM THIS MORNING/... ADDED THE EXTREME SOUTHERN PORTION OF THE FORECAST AREA TO THE FROST ADVISORY BECAUSE OF DECREASING DEW POINTS AND LIGHT WINDS AND CLEAR SKIES. DOWN IN THAT AREA THE FROST MAY BE JUST AREAS BECAUSE THE DEW POINTS COULD BE A DEGREE OR TWO HIGHER. DEW POINTS ARE DROPPING...SKIES WILL BE MOSTLY CLEAR. WENT WITH WIDESPREAD FROST AS NOT MUCH CLOUDS AND WITH SOME DRIER AIR TRYING TO MOVE IN...TEMPERATURES HAVE THE POTENTIAL TO GET A LITTLE COLDER THAN LAST NIGHT SO MORE FROST. THE CIRRUS OVER NORTHWEST INDIANA IS MAINLY THIN AND IN THE NORTHWEST FLOW SOME OF THAT COULD BRUSH THE SOUTHWEST PORTION OF THE FORECAST AREA OVERNIGHT. A LITTLE SHORT WAVE MOVED THROUGH DURING THE AFTERNOON AND NOW WITH THE WINDS SHIFTING TO THE NORTHWEST SOME CLOUDS OVER SOUTHWEST CANADA MAY DRIFT INTO NORTHWEST PENNSYLVANIA AND ASHTABULA COUNTY. IN FACT THE 21Z RUC MODELS SAYS IT WILL RAIN OVERNIGHT OVER NORTHWEST PENNSYLVANIA. I AM GOING TO KEEP IT DRY WITH SO MUCH RIDGING ALOFT EVEN THOUGH THE LAKE AND 850 MB TEMPERATURE DIFFERENCE IS NEAR 18C. WILL ADD BECOMING PARTLY CLOUDY FROM ASHTABULA COUNTY EAST. IF IT WASN`T FOR THAT THIS IS A TYPICAL PATTERN WHEN THE LAKESHORE CAN GET VERY COLD. BECAUSE OF THE CLOUD POTENTIAL LEFT PATCHY FROST FOR THE LAKESHORE AND JUST AREAS OF FROST INLAND. && .SHORT TERM /8 AM THIS MORNING THROUGH TUESDAY NIGHT/... REINFORCING PUSH OF COLD AIR...ESSENTIALLY A SECONDARY COLD FRONT... WILL CROSS ONTARIO AND QUEBEC LATER SUNDAY INTO MONDAY. COMBINE THIS WITH FRONTOGENESIS OVER THE UPPER MIDWEST AND WESTERN GREAT LAKES AND WILL SEE A NICE OVERRUNNING AREA DEVELOP. HIGH CLOUDS SHOULD INCREASE STEADILY SUNDAY. SHOWERS WILL BE LIMITED THOUGH. BEST UVV WILL DEVELOP IN THE MID LEVELS AND EVEN WITH A DRY AIRMASS SOME OF THE RAIN DROPS WILL REACH THE GROUND. ALL MODELS SEEM TO HINT AT A ZONE FROM SOUTHEAST LOWER MI TO NW PA SUNDAY NIGHT INTO MON WHERE SHOWERS ARE MOST LIKELY WITH A SHARP CUTOFF TO THE SOUTH. WILL KEEP MOST POPS IN THE SLIGHT CHANCE/CHANCE CATEGORY ACROSS THE NORTHERN COUNTIES AND KEEP THE FAR SOUTHERN COUNTIES DRY SUNDAY NIGHT INTO MONDAY. HIGH PRESSURE SHOULD BUILD BACK IN TUESDAY. LIGHT ENE FLOW WILL KEEP TEMPS IN CHECK ALTHOUGH WARM ADVECTION WILL CONTINUE. WEDNESDAY SHOULD BE THE WARMEST DAY AHEAD OF THE NEXT FRONT AS WIND COME AROUND FROM THE SSE WITH HIGHS IN THE 70S. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... MODELS MORE IN AGREEMENT IN DEVELOPING AN UPPER LOW OVER THE NATIONS MIDSECTION EARLY NEXT WEEK AND BOWLING IT EASTWARD. INTERESTINGLY... THE MODELS ARE FASTER EJECTING THE SYSTEM EASTWARD. I DOUBT THIS WILL HAPPEN AS UPPER LOWS...ESPECIALLY CUT OFFS...RARELY MOVE THAT QUICKLY. MAIN SYSTEM SHOULD PASS SOUTH OF THE AREA LATER THURSDAY WHILE A COLD FRONT PUSHES SOUTHEAST ACROSS THE GREAT LAKES. FRONT MAY JUST BRUSH THE AREA AS THE MAIN PUSH LOOKS TO BE EAST. WILL NOT FORECAST TOO HIGH OF A POP AT THIS TIME GIVEN THE UNCERTAINTY OF THE TRACK OF THE UPPER LOW AND THE EXTENT OF THE SHOWER THAT WILL DEVELOP AROUND THE LOW. ALSO SOME UNCERTAINTY ABOUT THE NORTHERN FRONT WHICH COULD ACT AS THE NORTHERN EDGE FOR THE MOISTURE/UVV. WILL KEEP A LOW POP CHANCE OF SHOWERS ACROSS THE EASTERN COUNTIES FRIDAY AND THEN DRY IT OUT FOR THE WEEKEND WITH TEMPS GENERALLY ABOVE NORMAL AS HEIGHTS/THICKNESSES RISE AS THE MAIN JET REMAINS WELL TO THE NORTH. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/... A FEW CLOUDS APPROACHING MVFR LEVELS ARE LOCATED ALONG THE LAKESHORE FROM LAKE COUNTY NORTHEAST INTO NY. THESE CLOUDS WILL AFFECT THE ERIE TAF BUT BELIEVE WITH THE LIGHT DOWNSLOPING WINDS THE CLOUD COVER WILL REMAIN SCATTERED. OTHERWISE EXPECT VFR CONDITIONS FOR THE REMAINDER OF NORTHERN OHIO WITH SOME PATCHY GROUND FOG POSSIBLE...ESPECIALLY AS WE GET CLOSER TO SUNRISE. CEILINGS WILL GRADUALLY LOWER THROUGH THE AFTERNOON INTO TONIGHT WITH A FEW SPRINKLES/LIGHT RAIN A POSSIBILITY FOR THE TOLEDO AREA. FOR NOW HAVE KEPT IT FROM THE KTOL TAF WITH CHANCES LIKELY INCREASING BEYOND 06Z MON. OUTLOOK...VFR CONDITIONS LOOK TO BE THE RULE AT ALL SITES EARLY NEXT WEEK. SOME MVFR CONDITIONS MAY OCCUR ALONG AND NORTH OF A TOL TO YNG LINE ON MONDAY WITHA WARM FRONT IN THE VICINITY. SHOWER AND THUNDERSTORMS MAY BE POSSIBLE LATE WEDNESDAY INTO THURSDAY AS THE NEXT STORM SYSTEMS APPROACH THE REGION. && .MARINE... QUIET CONDITIONS ON THE LAKE THROUGH SUNDAY WITH HIGH PRESSURE OVERHEAD. SOME INCREASE IN ENE WINDS FROM SUNDAY NIGHT THROUGH MONDAY NIGHT AS A BACKDOOR TYPE COLD FRONT MOVES ACROSS THE LAKE WITH THE HIGH REMAINING IN PLACE ACROSS SOUTHERN ONTARIO/QUEBEC. CONCERN WITH SMALL CRAFT POTENTIAL MONDAY INTO TUESDAY. HIGH MOVES SOUTHEAST WEDNESDAY ALLOWING WINDS TO COME AROUND TO THE SOUTHEAST. LEFT THE WINDS WITH A SOUTHERLY COMPONENT THROUGH THURSDAY. A WEAKENING FRONT APPROACHES FROM THE NORTHWEST WHILE A CUTOFF SYSTEM DRIFTS EASTWARD ACROSS THE TN VALLEY WEDNESDAY INTO THURSDAY. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR OHZ003-006>014- 017>023-027>033-036>038-047. PA...FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR PAZ002-003. MARINE...NONE. && $$ SYNOPSIS...ABE NEAR TERM...KIELTYKA SHORT TERM...KOSARIK LONG TERM...KOSARIK/OUDEMAN AVIATION...MULLEN MARINE...OUDEMAN oh AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 136 AM EDT SUN OCT 5 2008 .SYNOPSIS... HIGH PRESSURE WILL REBUILD OVER THE STATE THROUGH SUNDAY MORNING... BRINGING ANOTHER CHILLY NIGHT TO NORTHERN PENNSYLVANIA. WIDESPREAD FREEZING AND FROSTY TEMPERATURES WILL AFFECT NORTHERN SECTIONS ONCE AGAIN. ACROSS THE CENTRAL AND SOUTH...A WEAK DISTURBANCE AND MEANDERING FRONTAL BOUNDARY WILL BRING CLOUDS AND A SLIGHT CHANCE OF SOME VERY LIGHT RAIN LATE TONIGHT AND EARLY SUNDAY MORNING. A LARGE UPPER LEVEL DISTURBANCE WILL DROP SOUTHWARD OVER QUEBEC AND ONTARIO BY SUNDAY NIGHT...BRINGING INCREASING CLOUDS AND A CHILLY RAIN TO THE NORTH BEFORE HIGH PRESSURE RETURNS FOR MONDAY AND TUESDAY. MAINLY DRY WEATHER WILL PERSIST THROUGH MIDWEEK...WITH UNSETTLED CONDITIONS RETURNING FOR THE SECOND HALF OF THE WEEK AS THE HIGH DRIFTS OFFSHORE. && .NEAR TERM /UNTIL 9 AM THIS MORNING/... ANOTHER ROUND OF RELATIVELY WEAK ISENTROPIC LIFT ALONG THE I295-300K THETA SFCS...AND A BAND OF 850-925 HPA FRONTOGENETIC FORCING SLDING ENE ACROSS CENTRAL AND ERN PENN OVERNIGHT. THE RESULT WILL BE PLENTY OF CLOUDS NEAR...AND ACROSS THE ENTIRE REGION TO THE SOUTH OF INTERSTATE 80. 21Z 13 KM/40 KM RUC...18Z 12 KM NAM...AND 15Z SREF ALL CONCUR ON INCREASING LOW/MID LVL UVVEL ACROSS THE SCENT MTNS...EAST ACROSS THE SUSQ VALLEY AFTER MIDNIGHT WITH SOME VERY LIGHT QPF FOR SVRL HOURS UNTIL AROUND DAYBREAK SUNDAY. INCREASED THE TEMPS ACROSS THE CENTRAL AND SOUTH AS A RESULT OF THE EXPECTED WIDESPREAD CLOUD COVER...WHILE A FROSTY NIGHT IS STILL IN STORE FOR THE NRN MTNS...WHERE 4 COUNTIES (MCKEAN... POTTER...ELK AND CAMERON) EXPERIENCED A KILLING FREEZE EARLY SATURDAY MORNING...AND END TO THEIR GROWING SEASON. HAVE EXPANDED THE LATE NIGHT/EARLY SUNDAY FROST ADVISORY TO NOW INCLUDE NRN LYCOMING COUNTY. && .SHORT TERM /9 AM THIS MORNING THROUGH 6 PM MONDAY/... AFTER A SEVERAL HOUR PERIOD OF FROST-AND FREEZE-PRODUCING TEMPS OVERNIGHT... SUNDAY WILL START MAINLY CLEAR ACROSS THE NORTH WITH LAYER STRATO/ALTO CU EXITING EAST FROM THE SUSQ VALLEY DURING THE MID TO LATE MORNING HOURS. DURING THE AFTERNOON...SOME HIGH CLOUDS WILL RACE EASTWARD FROM THE OHIO VALLEY AHEAD OF A FILLING UPPER LOW DROPPING SOUTHWARD OVER ONTARIO AND QUEBEC. MOISTURE WILL CONTINUE TO POOL AHEAD OF A VERY SLOW MOVING WEST TO EAST ORIENTED BOUNDARY SUNDAY AFTERNOON...BUT IT APPEARS ANY PRECIP CHANCES OVER THE NORTHERN TIER WILL HOLD OFF UNTIL SUNDAY EVENING AT THE EARLIEST. MOSTLY CLOUDY SKIES (MAINLY ALTO CU BASED BETWEEN 8-12 KFT AGL) WILL SLIDE SE AND COVER MUCH OF THE FCST AREA AFTER 06Z MONDAY. && .LONG TERM /MONDAY NIGHT THROUGH SATURDAY/... TROUGH DROPS THROUGH REGION ON MONDAY BRINGING HIGH CHANCE TO LIKELY POPS ESPECIALLY IN THE NE. AFTER TROUGH SWEEPS THROUGH...HEIGHTS BOUNCE BACK BY RISING QUICKLY. A NARROW BUT HEALTHY RIDGE ALOFT WILL DEVELOP OVER THE UPPER GREAT LAKES TUE AND SLIDE OVERHEAD WED. THIS WILL BRING WARMER HIGHS WITH SEASONAL LOWS. SOME UNCERTAINTY IN THE FORECAST FOR LATE WEEK AS GFS AND ECMWF HAVE DIFFERENCES IN PLACEMENT OF FEATURES. SW FLOW WILL INCREASE MOISTURE ACROSS REGION THU INTO FRI BUT DYNAMICS WILL REMAIN CONFINED TO UPPER LOW OVER THE SE U.S. AND IN A WAVE SLIDING ACROSS S CANADA. SO ONLY SLIGHT CHANCE FOR RAIN THU WITH CHANCE ON FRI. THEN A BRIEF BREAK ON SAT BEFORE WEAK UPPER LOW OVER THE SOUTHEAST PUSHES SOME ADDITIONAL MOISTURE INTO PA VIA SE FLOW AND BRINGS CHANCE FOR RAIN SUN INTO MON. && .AVIATION /05Z SUNDAY THROUGH THURSDAY/... LATEST IR IMAGERY DEPICTS AREA OF STRATUS SLIDING NORTHEAST ALONG AND SOUTHEAST OF A LINE FROM KJST TO KIPT. SOME PATCHY DRIZZLE AND LIGHT RAIN SHOWERS WERE UNDERNEATH THIS CLOUD SHIELD AROUND KMDT AND WILL PERSIST THRU THE NEXT FEW HOURS. KBFD HAS CLEAR SKIES WHICH MAY LEAD TO PATCHY FOG DEVELOPING OVERNIGHT AND REDUCING VSBYS TO IFR BETWEEN 09-13Z. IF CLOUDS CAN DEPART KUNV/KAOO/KJST/KIPT PATCHY FOG AND MVFR COULD DEVELOP ALONG WITH SOME IFR TEMPO LIFR CIGS ASSOCIATED WITH THE FOG. WEAK SURFACE HIGH PRESSURE WILL INFLUENCE CENTRAL PA AIRFIELDS THIS AFTERNOON WITH VFR CIGS/VSBYS THRU THIS EVE. THE UPPER LEVEL TROUGH ACROSS WESTERN QUEBEC WILL SWING SOUTHEAST TONIGHT AND MAY BRING REDUCED CIGS AND VSBYS FOR KBFD/KUNV/KIPT. MOISTURE IS MARGINAL EARLY MONDAY...HOWEVER SOME PATCHY RAIN SHOWERS ACROSS NORTHERN PA AIRFIELDS CANNOT BE RULED OUT WITH FOG. A SECOND AREA OF HIGH PRESSURE SLIDES INTO EASTERN ONTARIO/WESTERN QUEBEC MON...WHICH COULD SET THE STAGE FOR COLD AIR SLIDING SOUTH FROM CANADA EARLY NEXT WEEK AS A WARM FRONTAL BNDRY APPROACHES FROM THE SW AND INTRODUCES A CHC FOR REDUCED CIGS/VSBYS MON/TUE WITH SOME SHOWERS. && .CTP WATCHES/WARNINGS/ADVISORIES... FROST ADVISORY UNTIL 9 AM EDT THIS MORNING FOR PAZ004-037-041- 042. && $$ SYNOPSIS...DEVOIR/LAMBERT NEAR TERM...DEVOIR/LAMBERT SHORT TERM...DEVOIR LONG TERM...RXR AVIATION...BEACHLER pa AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE ABERDEEN SD 937 AM CDT SUN OCT 5 2008 .UPDATE... MSAS ANLYS SHOWS SFC LOW SITTING IN SERN MT...WITH WEAK E-W ORIENTED BOUNDARY DRAPED ACROSS THE ND/SD BORDER. LATEST RUC AND NAM12 SHOW THAT PCPN COVERAGE SHOULD DIMINISH TO MORE OF A SCATTERED NATURE AS LEAD 7H VORT/TROF LIFT NORTH OF THE AREA...AND SECOND ONE PUSHES IN LATER THIS AFTERNOON. HAVE REDRAWN WEATHER/POP GRIDS TO REFLECT BETTER TIMING OF FEATURES THROUGH THE DAY. CURRENT FCSTD HIGHS LOOK GOOD WITH LITTLE DIURNAL TREND OFFERED. STILL LOOKS TO BE A SOGGY NEXT 24 HOURS. UPDATED AVIATION DISCUSSION BELOW. && .PREV DISCUSSION... .SHORT TERM...THROUGH TUESDAY UPPER TROUGH CONTINUES TO PROGRESS EASTWARDS...ROTATING A WEAK EAST-WEST ORIENTED H7 SHORTWAVE ACROSS THE CWA. THIS FEATURE...COUPLED WITH A WEAK LOW LEVEL JET...ARE THE PRIMARY REASONS FOR THE LINE OF SHOWERS AND INTERMITTENT THUNDER MOVING NORTHWARDS. EVENING SOUNDING REMAINED DRY BELOW 10KFT...BUT EXPECT DRY SUB CLOUD LAYER ALL BUT EVAPORATED BY THIS POINT. THEREFORE WILL BEGIN PERIOD WITH WIDESPREAD FOR COVERAGE WITH SHOWERS/THUNDERSTORMS. MIXING OF 35KT LOW LEVEL JET TO SURFACE COULD PRODUCE STRONG GUSTS BUT EXPECT TO REMAIN WELL BELOW WARNING CRITERIA. AFTER THE H7 WAVE PASSES WILL CONTINUE TO ADVERTISE HIGH POPS AS GUIDANCES SUGGESTS BROAD ISENTROPIC UPGLIDE PERSISTS THROUGH MONDAY AM. LI/MUCAPE VALUES REMAIN HIGH ENOUGH THAT THUNDER CAN NOT BE RULED OUT. SREF PWAT ANOMALIES CONTINUE TO INCREASE TODAY...REACHING 3 TO 4 STANDARD DEVIATIONS ABOVE CLIMATOLOGY. AS UPPER LOW CONTINUES TO SIT AND SPIN ACROSS THE CENTRAL PLAINS STATES MONDAY...A DEVELOPING TROWAL FEATURE OVER THE EASTERN CWA WILL RESULT IN DECREASE POPS TUESDAY AM IN THE WEST...WITH SHOWERS HANG ON IN THE EAST. DIURNAL TRENDS THIS PERIOD WILL BE INFLUENCED HEAVILY BY CLOUD COVER. GUIDANCE VALUES REFLECT THIS WELL...SO WILL GO WITH MAV/MET GUIDANCE. .LONG TERM...TUESDAY NIGHT THROUGH SATURDAY THE EXTENDED PERIOD STARTS OFF WITH AN UPPER TROUGH CENTERED FROM MINNESOTA TO EASTERN OKLAHOMA...WITH A SURFACE FRONT JUST EAST OF THE REGION. HIGH PRESSURE SLIDES OVER THE PLAINS BEHIND THE EXITING SYSTEM TUESDAY NIGHT...THEN REMAINS DOMINANT OVER THE AREA THROUGH THE DAY THURSDAY...WITH DRY CONDITIONS EXPECTED. THE MODELS BEGIN TO DIVERGE GREATLY WITH THEIR SOLUTIONS BEGINNING THURSDAY NIGHT. BOTH HINT AT A LOW PRESSURE SYSTEM DEVELOPING SOMEWHERE OVER THE WESTERN HIGH PLAINS THURSDAY NIGHT...SO WILL LEAVE A SMALL POP IN FOR THAT TIME PERIOD. FRIDAY AND SATURDAY BECOME EXTREMELY MESSY WITH BIG DIFFERENCES IN THE MODELS. THE GFS STRENGTHENS A LOW PRESSURE SYSTEM SOUTH OF THE REGION...RESULTING IN PRECIPITATION OVER THE CWA ON FRIDAY. IT THEN MOVES THE SYSTEM NORTHEAST OF THE AREA WITH HIGH PRESSURE SETTLING IN OVER THE PLAINS ON SATURDAY. THE ECMWF ON THE OTHER HAND TRACKS HIGH PRESSURE ACROSS THE AREA ON FRIDAY...THEN DEVELOPS AN INTENSE LOW PRESSURE SYSTEM SOUTH OF THE REGION WITH A LARGE AREA OF PRECIPITATION OVER THE NORTHERN PLAINS ON SATURDAY. DUE TO THESE SIGNIFICANT DIFFERENCES...WILL STICK WITH PERSISTENCE AND HAVE NOT MADE ANY CHANGES TO THE FRIDAY OR SATURDAY TIME PERIODS. TEMPERATURES WILL BE RIGHT AROUND NORMAL WEDNESDAY AND THURSDAY AS H85 TEMPS REMAIN IN THE SINGLE DIGITS. AGAIN...DUE TO MODEL DIFFERENCES...TEMPERATURES FOR THE LATTER TWO DAYS OF THE PERIOD ARE TRICKY...WITH THE GFS BRINGING MUCH COOLER AIR INTO THE AREA VS THE OTHER MODELS. POTENTIAL IS THERE FOR DAYTIME HIGHS TO NOT GET OUT OF THE 50S BOTH FRIDAY AND SATURDAY. && .AVIATION... SCT -SHRAS ACROSS THE AREA WILL BECOME MORE NMRS LATER IN THE DAY ACROSS MUCH OF THE AREA. OVC VFR CIGS WILL ALSO GRADUALLY LOWER INTO THE MVFR CATEGORY BY LATER IN THE DAY AND INTO THE OVERNIGHT HOURS. VSBYS MAY FALL TO 3-5SM WITHIN HEAVIER SHRAS. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. && $$ UPDATE...HINTZ SHORT TERM...CONNELLY LONG TERM...PARKIN AVIATION...TMT WEATHER.GOV/ABERDEEN sd AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 848 PM CDT MON OCT 6 2008 .UPDATE...PROBABILITIES WERE RECONFIGURED FROM NOW TIL MIDNIGHT AS A SUBSIDENT SOUTHWEST TO WEST FLOW ALOFT WAS LIMITING DEVELOPMENTS. NEW RAOB DATA FROM KDRT AND KCRP REINFORCE IDEA AND POINT TO SEVERAL INVERSIONS IN THE LOW AND MID LEVELS AS TEMPERATURES HAD INCREASED AND MOISTURE DECREASED IN THE ZONE OF SOUTH-WESTERLIES ALOFT. AFTER MIDNIGHT..PROBABILITIES STILL ON TRACK AS LATEST RUC SHOWS LAST DISTURBANCE PUSHING TROUGH THROUGH EASTERN CWA INTO RICHER MOISTURE FIELD. THIS WILL DESTABILIZE UPPER LEVELS AT THE SAME TIME LOWERING SUBSIDENT SOUTHWEST WIND INFLUENCE. THUS..ACTIVITY SHOULD FORM AGAIN..MAINLY EAST OF THE I-35 CORRIDOR LATE TONIGHT. && .PREV DISCUSSION... /ISSUED 646 PM CDT MON OCT 6 2008/ AVIATION... RADAR CONVECTIVE TRENDS SHOW A SMALL POCKET OF WEAK SHOWER ACTIVITY TO AFFECT THE SAN ANTONIO METRO TERMINALS THROUGH AROUND 2Z. THE MORE SIGNIFICANT WEATHER FEATURE IS FORMING ALONG A ACT TO JCT AXIS. THIS CONVECTIVE FOCUS SHOULD DROP SLOWLY ESE THROUGH THE NIGHT, AFFECTING THE AUS AREA AFTER 03Z AND POSSIBLY GLANCING THE SAT METRO AREA AFTER 08Z. BY 11Z, MOST OF THE CONVECTIVE WEATHER SHOULD SHIFT EAST OF THE I-35 CORRIDOR WITH A WEAK COLD FRONT TO BRING NEARLY STEADY NW WINDS OF AROUND 8-14 KTS ACROSS THE AREA THROUGH THE END OF THE TAF PERIOD. NOCTURNAL STRATOCUMULUS FOR THE ESCARPMENT TERMINALS SHOULD FORM MOSTLY AFTER 04Z WITH THE ADDED INSTABILITY AND MID CLOUD PRESENCE IN THE AREA. VFR CONDITIONS ARE EXEPCTED TO RESUME BY DAYBREAK. PREV DISCUSSION... /ISSUED 302 PM CDT MON OCT 6 2008/ DISCUSSION... THIS AFTERNOON ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WERE DEVELOPING ACROSS OUR NORTHEAST COUNTIES IN THE WARM AND UNSTABLE AIRMASS...IN ADVANCE OF THE DRY LINE AND COLD FRONT. THE PRE-FRONTAL TROF/DRY LINE IS EAST OF K6R6 AND KSJT WITH THE COLD FRONT HAVING PASSED THROUGH KINK AND KLBB. THE BEST LOW LEVEL CONVERGENCE WILL OCCUR ALONG AND AHEAD OF THE FRONTAL BOUNDARY ALONG AND EAST OF HIGHWAY 281 WHERE THE BEST LOW LEVEL MOISTURE AXIS IS LOCATED. THUS THE BEST CHANCE FOR MEASURABLE RAINFALL ASSOCIATED WITH THE FROPA WILL BE MAINLY EAST OF HIGHWAY 281. THE FRONTAL BOUNDARY WILL MOVE ACROSS OUR CWFA OVERNIGHT AND WILL CLEAR OUR SOUTHEAST COUNTIES TUESDAY MORNING. THERE WILL BE SOME POST- FRONTAL SHOWERS LINGERING ACROSS OUR SOUTHEAST COUNTIES TUESDAY AFTERNOON AS THE COLD FRONT CLEARS THE MIDDLE TEXAS COAST. HIGH PRESSURE AT THE SURFACE AND ALOFT WILL DOMINATE THE WEATHER ACROSS SOUTH CENTRAL TEXAS WEDNESDAY AND THURSDAY. THIS PATTERN WILL RESULT IN COOL MORNINGS AND WARM AFTERNOONS. GULF MOISTURE WILL BEGIN TO RETURN TO THE CWFA ON FRIDAY. ATMOSPHERIC MOISTURE LEVELS WILL INCREASE SATURDAY THRU MONDAY IN ADVANCE OF THE NEXT UPPER LEVEL TROF AND ASSOCIATED COLD FRONT. THUS A WET WEEKEND IS EXPECTED. ATTM THE NEXT COLD FRONT IS EXPECTED TO MOVE ACROSS SOUTH CENTRAL TEXAS MONDAY NIGHT OF NEXT WEEK. THE GFS HAS BEEN INCONSISTENT WITH THE TIMING OF THIS FRONT SO WENT WITH THE HPC DAY 7 GRAPHIC FOR FRONTAL TIMING. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 67 86 59 88 57 / 30 10 0 0 0 AUSTIN BERGSTROM INTL AIRPORT 66 86 54 86 52 / 30 10 0 0 0 DEL RIO INTL AIRPORT 68 88 59 87 58 / 10 - 0 0 0 SAN ANTONIO INTL AIRPORT 68 86 58 88 54 / 30 10 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 02/18 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AMARILLO TX 1139 PM CDT SUN OCT 5 2008 .AVIATION... SHOWERS CONTINUE TO REMAIN EAST OF THE TERMINALS THIS EVENING...AND EXPECTING THIS TO PERSIST THROUGHOUT THE OVERNIGHT. THE BIG QUESTION WILL BE IF LOW CLOUDS FORM...AND IF SO HOW LOW DO CEILINGS DROP. STILL THINKING AMA AND GUY HAVE THE BEST CHANCE OF LOW CEILINGS...SO CONTINUED WITH MVFR CONDITIONS THROUGH 12Z. CEILINGS COULD DROP A LITTLE LOWER...BUT NOT CONFIDENT ENOUGH FOR IFR CONDITIONS AS OF NOW. LEFT VCSH REMARKS IN GUY IN CASE ANY WRAP AROUND PRECIP SKIRTS THE NORTHERN AREAS OF THE REGION. UPPER TROUGH SWINGS THROUGHOUT THE PANHANDLES TOMORROW WITH A WIND SHIFT TO THE NORTHWEST...FIRST AT DHT THEN AT AMA AND GUY. TAB && .PREV DISCUSSION... /ISSUED 1057 PM CDT SUN OCT 5 2008/ UPDATE... ANOTHER REVISED PACKAGE SENT TO LOWER POPS ACCORDINGLY BASED ON RADAR TRENDS. ALSO LOWERED MIN TEMPS TONIGHT SINCE MANY LOCATIONS AT OR NEAR EARLIER FCST LOWS. ANDRADE PREV DISCUSSION... /ISSUED 729 PM CDT SUN OCT 5 2008/ UPDATE... SENT OUT A QUICK UPDATE TO RE ORIENT POPS BASED ON LATEST RADAR TRENDS...THAT IS A TIGHT GRADIENT FROM W TO E. ANDRADE PREV DISCUSSION... /ISSUED 647 PM CDT SUN OCT 5 2008/ AVIATION... BULK OF THE SHOWER AND THUNDERSTORM ACTIVITY HAS STAYED EAST OF THE TERMINALS THIS AFTERNOON. EXPECT THIS TREND TO CONTINUE INTO THE EVENING AND OVERNIGHT HOURS. THINK LOW CLOUDS WILL BE MOST PREVALENT AT THE GUY AND AMA TAF SITES...THEREFORE INSERTED MVFR CEILINGS BEGINNING AT 03/04Z. ALSO INCLUDED SOME VCSH REMARKS AT THE GUY TAF SITE TOMORROW MORNING FOR ANY WRAP AROUND RAIN. VFR CONDITIONS SHOULD RETURN DURING THE MID MORNING HOURS. ONLY OTHER AVIATION CONCERN WILL BE THE WINDS. TIMED WIND SHIFT ACCORDINGLY ACROSS THE TERMINALS WITH A NORTHWEST WIND AT DHT AT 09Z...AND THEN AMA AND GUY AS THE UPPER TROUGH SWINGS THROUGH THE AREA. TAB PREV DISCUSSION... /ISSUED 336 PM CDT SUN OCT 5 2008/ DISCUSSION... MAIN FORECAST CONCERN CONTINUES TO CENTER ON STRONG UPPER TROUGH WEST OF THE AREA. BASE OF STRONG UPPER TROUGH WAS OVER WESTERN NEW MEXICO THIS AFTERNOON WITH STRONG HEIGHT FALLS AND UPPER JET STREAK ROUNDING THE BASE OF THE TROUGH. SYNOPTIC SCALE ASCENT HAS LEAD TO WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS MUCH OF EASTERN NEW MEXICO/WESTERN TEXAS TODAY. ALTHOUGH WIDESPREAD CLOUDS/RAIN OVER THE PANHANDLES HAS RESULTED IN LIMITED SURFACE HEATING/MID LEVEL LAPSE RATES...CONVECTION IS STILL POSSIBLE THIS EVENING. HOWEVER FURTHER WEST...LESS CLOUD COVER HAS RESULTED IN GREATER POTENTIAL FOR SEVERE STORMS WITH RUC MESOSCALE ANALYSIS INDICATING SBCAPES AROUND 1000 J/KG. SYSTEM WILL CONTINUE TO PUSH EAST TONIGHT AND WITH LIFT STILL MAXIMIZED AHEAD OF MAIN UPPER CIRCULATION...PRECIP WILL LAST INTO MONDAY. UPPER TROUGH MOVES OVER THE PANHANDLES MONDAY MORNING AND LIFTS INTO CENTRAL KANSAS DURING THE AFTERNOON WITH THE SURFACE LOW FOLLOWING A SIMILAR ROUTE. MID LEVEL MOISTURE WRAPPING AROUND THE MAIN UPPER CIRCULATION WILL SUPPORT WRAP AROUND SHOWERS AND ISOLATED THUNDERSTORMS DURING THE DAY. PRECIP WILL END FROM WEST TO EAST DURING THE DAY WITH THE BULK OF ANY SHOWERS/CONVECTION ENDING BY LATE AFTERNOON. LOW CLOUDS WILL BE SLOW TO DEPART...WHICH WILL LIKELY LEAD TO TEMPS ONLY CLIMBING INTO 70S WITH PERHAPS COOLER 60S FARTHER NORTH WHERE THE BETTER POTENTIAL FOR WRAP AROUND SHOWERS LIE. UPPER LEVEL HEIGHTS WILL BE SLOW TO RISE ACROSS THE HIGH PLAINS TUESDAY. HOWEVER AS THE UPPER TROUGH LIFTS INTO THE LOWER GREAT LAKES WEDNESDAY...THE UPPER LEVELS WILL TRANSITION TOWARD MORE OF A ZONAL FLOW REGIME. TUESDAY WILL ONCE AGAIN SEE TEMPS IN THE 70S AS SURFACE HIGH PRESSURE BUILDS INTO THE PLAINS. BUT AS THIS HIGH SLIDES SOUTHEAST OF THE AREA...SURFACE TROUGH WILL DEVELOP IN THE LEE OF THE ROCKIES. WITH THE SURFACE GRADIENT TURNING MORE OUT OF THE SOUTH...LOW LEVEL WARM AIR ADVECTION WILL BE MORE PRONOUNCED AND WILL LEAD TO TEMPS CLIMBING INTO THE UPPER 70S/LOWER 80S. ATTENTION THEN TURNS TO NEXT UPPER TROUGH THAT IS SLATED TO DROP SOUTH...INTO THE NORTHERN PLAINS BY THE END OF THE WEEK. MEDIUM RANGE MODELS DISPLAY TIMING AND TRACKING DISCREPANCIES ALTHOUGH STILL LOOKS LIKE THIS SYSTEM WILL BRING THE FIRST SIGNIFICANT COLD AIR INTRUSION TO THE AREA BY SUNDAY ALONG WITH THE NEXT POSSIBILITY OF PRECIP. CLK FIRE WEATHER... HIGH RELATIVE HUMIDITIES AND MODERATE RAINFALL TODAY WILL HELP ALLEVIATE ANY CRITICAL FIRE WEATHER CONDITIONS FOR A LITTLE WHILE. DRY AND WARMER AIR WILL MOVE INTO THE PANHANDLES FOR MUCH OF THE WEEK AS THE UPPER TROUGH HEADS INTO THE LOWER GREAT LAKES REGION WEDNESDAY WHILE THE UPPER FLOW FLATTENS. MINIMUM RELATIVE HUMIDITIES GENERALLY AT OR AROUND 20 PERCENT AND 20 FOOT WINDS UNDER 25 KNOTS WILL PRECLUDE ANY CRITICAL FIRE WEATHER CONDITIONS THROUGH THE END OF THE WEEK. CLK && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 10/02 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AMARILLO TX 1057 PM CDT SUN OCT 5 2008 .UPDATE... ANOTHER REVISED PACKAGE SENT TO LOWER POPS ACCORDINGLY BASED ON RADAR TRENDS. ALSO LOWERED MIN TEMPS TONIGHT SINCE MANY LOCATIONS AT OR NEAR EARLIER FCST LOWS. ANDRADE && .PREV DISCUSSION... /ISSUED 729 PM CDT SUN OCT 5 2008/ UPDATE... SENT OUT A QUICK UPDATE TO RE ORIENT POPS BASED ON LATEST RADAR TRENDS...THAT IS A TIGHT GRADIENT FROM W TO E. ANDRADE PREV DISCUSSION... /ISSUED 647 PM CDT SUN OCT 5 2008/ AVIATION... BULK OF THE SHOWER AND THUNDERSTORM ACTIVITY HAS STAYED EAST OF THE TERMINALS THIS AFTERNOON. EXPECT THIS TREND TO CONTINUE INTO THE EVENING AND OVERNIGHT HOURS. THINK LOW CLOUDS WILL BE MOST PREVALENT AT THE GUY AND AMA TAF SITES...THEREFORE INSERTED MVFR CEILINGS BEGINNING AT 03/04Z. ALSO INCLUDED SOME VCSH REMARKS AT THE GUY TAF SITE TOMORROW MORNING FOR ANY WRAP AROUND RAIN. VFR CONDITIONS SHOULD RETURN DURING THE MID MORNING HOURS. ONLY OTHER AVIATION CONCERN WILL BE THE WINDS. TIMED WIND SHIFT ACCORDINGLY ACROSS THE TERMINALS WITH A NORTHWEST WIND AT DHT AT 09Z...AND THEN AMA AND GUY AS THE UPPER TROUGH SWINGS THROUGH THE AREA. TAB PREV DISCUSSION... /ISSUED 336 PM CDT SUN OCT 5 2008/ DISCUSSION... MAIN FORECAST CONCERN CONTINUES TO CENTER ON STRONG UPPER TROUGH WEST OF THE AREA. BASE OF STRONG UPPER TROUGH WAS OVER WESTERN NEW MEXICO THIS AFTERNOON WITH STRONG HEIGHT FALLS AND UPPER JET STREAK ROUNDING THE BASE OF THE TROUGH. SYNOPTIC SCALE ASCENT HAS LEAD TO WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS MUCH OF EASTERN NEW MEXICO/WESTERN TEXAS TODAY. ALTHOUGH WIDESPREAD CLOUDS/RAIN OVER THE PANHANDLES HAS RESULTED IN LIMITED SURFACE HEATING/MID LEVEL LAPSE RATES...CONVECTION IS STILL POSSIBLE THIS EVENING. HOWEVER FURTHER WEST...LESS CLOUD COVER HAS RESULTED IN GREATER POTENTIAL FOR SEVERE STORMS WITH RUC MESOSCALE ANALYSIS INDICATING SBCAPES AROUND 1000 J/KG. SYSTEM WILL CONTINUE TO PUSH EAST TONIGHT AND WITH LIFT STILL MAXIMIZED AHEAD OF MAIN UPPER CIRCULATION...PRECIP WILL LAST INTO MONDAY. UPPER TROUGH MOVES OVER THE PANHANDLES MONDAY MORNING AND LIFTS INTO CENTRAL KANSAS DURING THE AFTERNOON WITH THE SURFACE LOW FOLLOWING A SIMILAR ROUTE. MID LEVEL MOISTURE WRAPPING AROUND THE MAIN UPPER CIRCULATION WILL SUPPORT WRAP AROUND SHOWERS AND ISOLATED THUNDERSTORMS DURING THE DAY. PRECIP WILL END FROM WEST TO EAST DURING THE DAY WITH THE BULK OF ANY SHOWERS/CONVECTION ENDING BY LATE AFTERNOON. LOW CLOUDS WILL BE SLOW TO DEPART...WHICH WILL LIKELY LEAD TO TEMPS ONLY CLIMBING INTO 70S WITH PERHAPS COOLER 60S FARTHER NORTH WHERE THE BETTER POTENTIAL FOR WRAP AROUND SHOWERS LIE. UPPER LEVEL HEIGHTS WILL BE SLOW TO RISE ACROSS THE HIGH PLAINS TUESDAY. HOWEVER AS THE UPPER TROUGH LIFTS INTO THE LOWER GREAT LAKES WEDNESDAY...THE UPPER LEVELS WILL TRANSITION TOWARD MORE OF A ZONAL FLOW REGIME. TUESDAY WILL ONCE AGAIN SEE TEMPS IN THE 70S AS SURFACE HIGH PRESSURE BUILDS INTO THE PLAINS. BUT AS THIS HIGH SLIDES SOUTHEAST OF THE AREA...SURFACE TROUGH WILL DEVELOP IN THE LEE OF THE ROCKIES. WITH THE SURFACE GRADIENT TURNING MORE OUT OF THE SOUTH...LOW LEVEL WARM AIR ADVECTION WILL BE MORE PRONOUNCED AND WILL LEAD TO TEMPS CLIMBING INTO THE UPPER 70S/LOWER 80S. ATTENTION THEN TURNS TO NEXT UPPER TROUGH THAT IS SLATED TO DROP SOUTH...INTO THE NORTHERN PLAINS BY THE END OF THE WEEK. MEDIUM RANGE MODELS DISPLAY TIMING AND TRACKING DISCREPANCIES ALTHOUGH STILL LOOKS LIKE THIS SYSTEM WILL BRING THE FIRST SIGNIFICANT COLD AIR INTRUSION TO THE AREA BY SUNDAY ALONG WITH THE NEXT POSSIBILITY OF PRECIP. CLK FIRE WEATHER... HIGH RELATIVE HUMIDITIES AND MODERATE RAINFALL TODAY WILL HELP ALLEVIATE ANY CRITICAL FIRE WEATHER CONDITIONS FOR A LITTLE WHILE. DRY AND WARMER AIR WILL MOVE INTO THE PANHANDLES FOR MUCH OF THE WEEK AS THE UPPER TROUGH HEADS INTO THE LOWER GREAT LAKES REGION WEDNESDAY WHILE THE UPPER FLOW FLATTENS. MINIMUM RELATIVE HUMIDITIES GENERALLY AT OR AROUND 20 PERCENT AND 20 FOOT WINDS UNDER 25 KNOTS WILL PRECLUDE ANY CRITICAL FIRE WEATHER CONDITIONS THROUGH THE END OF THE WEEK. CLK && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AMARILLO TX 729 PM CDT SUN OCT 5 2008 .UPDATE... SENT OUT A QUICK UPDATE TO RE ORIENT POPS BASED ON LATEST RADAR TRENDS...THAT IS A TIGHT GRADIENT FROM W TO E. ANDRADE && .PREV DISCUSSION... /ISSUED 647 PM CDT SUN OCT 5 2008/ AVIATION... BULK OF THE SHOWER AND THUNDERSTORM ACTIVITY HAS STAYED EAST OF THE TERMINALS THIS AFTERNOON. EXPECT THIS TREND TO CONTINUE INTO THE EVENING AND OVERNIGHT HOURS. THINK LOW CLOUDS WILL BE MOST PREVALENT AT THE GUY AND AMA TAF SITES...THEREFORE INSERTED MVFR CEILINGS BEGINNING AT 03/04Z. ALSO INCLUDED SOME VCSH REMARKS AT THE GUY TAF SITE TOMORROW MORNING FOR ANY WRAP AROUND RAIN. VFR CONDITIONS SHOULD RETURN DURING THE MID MORNING HOURS. ONLY OTHER AVIATION CONCERN WILL BE THE WINDS. TIMED WIND SHIFT ACCORDINGLY ACROSS THE TERMINALS WITH A NORTHWEST WIND AT DHT AT 09Z...AND THEN AMA AND GUY AS THE UPPER TROUGH SWINGS THROUGH THE AREA. TAB PREV DISCUSSION... /ISSUED 336 PM CDT SUN OCT 5 2008/ DISCUSSION... MAIN FORECAST CONCERN CONTINUES TO CENTER ON STRONG UPPER TROUGH WEST OF THE AREA. BASE OF STRONG UPPER TROUGH WAS OVER WESTERN NEW MEXICO THIS AFTERNOON WITH STRONG HEIGHT FALLS AND UPPER JET STREAK ROUNDING THE BASE OF THE TROUGH. SYNOPTIC SCALE ASCENT HAS LEAD TO WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS MUCH OF EASTERN NEW MEXICO/WESTERN TEXAS TODAY. ALTHOUGH WIDESPREAD CLOUDS/RAIN OVER THE PANHANDLES HAS RESULTED IN LIMITED SURFACE HEATING/MID LEVEL LAPSE RATES...CONVECTION IS STILL POSSIBLE THIS EVENING. HOWEVER FURTHER WEST...LESS CLOUD COVER HAS RESULTED IN GREATER POTENTIAL FOR SEVERE STORMS WITH RUC MESOSCALE ANALYSIS INDICATING SBCAPES AROUND 1000 J/KG. SYSTEM WILL CONTINUE TO PUSH EAST TONIGHT AND WITH LIFT STILL MAXIMIZED AHEAD OF MAIN UPPER CIRCULATION...PRECIP WILL LAST INTO MONDAY. UPPER TROUGH MOVES OVER THE PANHANDLES MONDAY MORNING AND LIFTS INTO CENTRAL KANSAS DURING THE AFTERNOON WITH THE SURFACE LOW FOLLOWING A SIMILAR ROUTE. MID LEVEL MOISTURE WRAPPING AROUND THE MAIN UPPER CIRCULATION WILL SUPPORT WRAP AROUND SHOWERS AND ISOLATED THUNDERSTORMS DURING THE DAY. PRECIP WILL END FROM WEST TO EAST DURING THE DAY WITH THE BULK OF ANY SHOWERS/CONVECTION ENDING BY LATE AFTERNOON. LOW CLOUDS WILL BE SLOW TO DEPART...WHICH WILL LIKELY LEAD TO TEMPS ONLY CLIMBING INTO 70S WITH PERHAPS COOLER 60S FARTHER NORTH WHERE THE BETTER POTENTIAL FOR WRAP AROUND SHOWERS LIE. UPPER LEVEL HEIGHTS WILL BE SLOW TO RISE ACROSS THE HIGH PLAINS TUESDAY. HOWEVER AS THE UPPER TROUGH LIFTS INTO THE LOWER GREAT LAKES WEDNESDAY...THE UPPER LEVELS WILL TRANSITION TOWARD MORE OF A ZONAL FLOW REGIME. TUESDAY WILL ONCE AGAIN SEE TEMPS IN THE 70S AS SURFACE HIGH PRESSURE BUILDS INTO THE PLAINS. BUT AS THIS HIGH SLIDES SOUTHEAST OF THE AREA...SURFACE TROUGH WILL DEVELOP IN THE LEE OF THE ROCKIES. WITH THE SURFACE GRADIENT TURNING MORE OUT OF THE SOUTH...LOW LEVEL WARM AIR ADVECTION WILL BE MORE PRONOUNCED AND WILL LEAD TO TEMPS CLIMBING INTO THE UPPER 70S/LOWER 80S. ATTENTION THEN TURNS TO NEXT UPPER TROUGH THAT IS SLATED TO DROP SOUTH...INTO THE NORTHERN PLAINS BY THE END OF THE WEEK. MEDIUM RANGE MODELS DISPLAY TIMING AND TRACKING DISCREPANCIES ALTHOUGH STILL LOOKS LIKE THIS SYSTEM WILL BRING THE FIRST SIGNIFICANT COLD AIR INTRUSION TO THE AREA BY SUNDAY ALONG WITH THE NEXT POSSIBILITY OF PRECIP. CLK FIRE WEATHER... HIGH RELATIVE HUMIDITIES AND MODERATE RAINFALL TODAY WILL HELP ALLEVIATE ANY CRITICAL FIRE WEATHER CONDITIONS FOR A LITTLE WHILE. DRY AND WARMER AIR WILL MOVE INTO THE PANHANDLES FOR MUCH OF THE WEEK AS THE UPPER TROUGH HEADS INTO THE LOWER GREAT LAKES REGION WEDNESDAY WHILE THE UPPER FLOW FLATTENS. MINIMUM RELATIVE HUMIDITIES GENERALLY AT OR AROUND 20 PERCENT AND 20 FOOT WINDS UNDER 25 KNOTS WILL PRECLUDE ANY CRITICAL FIRE WEATHER CONDITIONS THROUGH THE END OF THE WEEK. CLK && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE AMARILLO TX 647 PM CDT SUN OCT 5 2008 .AVIATION... BULK OF THE SHOWER AND THUNDERSTORM ACTIVITY HAS STAYED EAST OF THE TERMINALS THIS AFTERNOON. EXPECT THIS TREND TO CONTINUE INTO THE EVENING AND OVERNIGHT HOURS. THINK LOW CLOUDS WILL BE MOST PREVALENT AT THE GUY AND AMA TAF SITES...THEREFORE INSERTED MVFR CEILINGS BEGINNING AT 03/04Z. ALSO INCLUDED SOME VCSH REMARKS AT THE GUY TAF SITE TOMORROW MORNING FOR ANY WRAP AROUND RAIN. VFR CONDITIONS SHOULD RETURN DURING THE MID MORNING HOURS. ONLY OTHER AVIATION CONCERN WILL BE THE WINDS. TIMED WIND SHIFT ACCORDINGLY ACROSS THE TERMINALS WITH A NORTHWEST WIND AT DHT AT 09Z...AND THEN AMA AND GUY AS THE UPPER TROUGH SWINGS THROUGH THE AREA. TAB && .PREV DISCUSSION... /ISSUED 336 PM CDT SUN OCT 5 2008/ DISCUSSION... MAIN FORECAST CONCERN CONTINUES TO CENTER ON STRONG UPPER TROUGH WEST OF THE AREA. BASE OF STRONG UPPER TROUGH WAS OVER WESTERN NEW MEXICO THIS AFTERNOON WITH STRONG HEIGHT FALLS AND UPPER JET STREAK ROUNDING THE BASE OF THE TROUGH. SYNOPTIC SCALE ASCENT HAS LEAD TO WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS MUCH OF EASTERN NEW MEXICO/WESTERN TEXAS TODAY. ALTHOUGH WIDESPREAD CLOUDS/RAIN OVER THE PANHANDLES HAS RESULTED IN LIMITED SURFACE HEATING/MID LEVEL LAPSE RATES...CONVECTION IS STILL POSSIBLE THIS EVENING. HOWEVER FURTHER WEST...LESS CLOUD COVER HAS RESULTED IN GREATER POTENTIAL FOR SEVERE STORMS WITH RUC MESOSCALE ANALYSIS INDICATING SBCAPES AROUND 1000 J/KG. SYSTEM WILL CONTINUE TO PUSH EAST TONIGHT AND WITH LIFT STILL MAXIMIZED AHEAD OF MAIN UPPER CIRCULATION...PRECIP WILL LAST INTO MONDAY. UPPER TROUGH MOVES OVER THE PANHANDLES MONDAY MORNING AND LIFTS INTO CENTRAL KANSAS DURING THE AFTERNOON WITH THE SURFACE LOW FOLLOWING A SIMILAR ROUTE. MID LEVEL MOISTURE WRAPPING AROUND THE MAIN UPPER CIRCULATION WILL SUPPORT WRAP AROUND SHOWERS AND ISOLATED THUNDERSTORMS DURING THE DAY. PRECIP WILL END FROM WEST TO EAST DURING THE DAY WITH THE BULK OF ANY SHOWERS/CONVECTION ENDING BY LATE AFTERNOON. LOW CLOUDS WILL BE SLOW TO DEPART...WHICH WILL LIKELY LEAD TO TEMPS ONLY CLIMBING INTO 70S WITH PERHAPS COOLER 60S FARTHER NORTH WHERE THE BETTER POTENTIAL FOR WRAP AROUND SHOWERS LIE. UPPER LEVEL HEIGHTS WILL BE SLOW TO RISE ACROSS THE HIGH PLAINS TUESDAY. HOWEVER AS THE UPPER TROUGH LIFTS INTO THE LOWER GREAT LAKES WEDNESDAY...THE UPPER LEVELS WILL TRANSITION TOWARD MORE OF A ZONAL FLOW REGIME. TUESDAY WILL ONCE AGAIN SEE TEMPS IN THE 70S AS SURFACE HIGH PRESSURE BUILDS INTO THE PLAINS. BUT AS THIS HIGH SLIDES SOUTHEAST OF THE AREA...SURFACE TROUGH WILL DEVELOP IN THE LEE OF THE ROCKIES. WITH THE SURFACE GRADIENT TURNING MORE OUT OF THE SOUTH...LOW LEVEL WARM AIR ADVECTION WILL BE MORE PRONOUNCED AND WILL LEAD TO TEMPS CLIMBING INTO THE UPPER 70S/LOWER 80S. ATTENTION THEN TURNS TO NEXT UPPER TROUGH THAT IS SLATED TO DROP SOUTH...INTO THE NORTHERN PLAINS BY THE END OF THE WEEK. MEDIUM RANGE MODELS DISPLAY TIMING AND TRACKING DISCREPANCIES ALTHOUGH STILL LOOKS LIKE THIS SYSTEM WILL BRING THE FIRST SIGNIFICANT COLD AIR INTRUSION TO THE AREA BY SUNDAY ALONG WITH THE NEXT POSSIBILITY OF PRECIP. CLK FIRE WEATHER... HIGH RELATIVE HUMIDITIES AND MODERATE RAINFALL TODAY WILL HELP ALLEVIATE ANY CRITICAL FIRE WEATHER CONDITIONS FOR A LITTLE WHILE. DRY AND WARMER AIR WILL MOVE INTO THE PANHANDLES FOR MUCH OF THE WEEK AS THE UPPER TROUGH HEADS INTO THE LOWER GREAT LAKES REGION WEDNESDAY WHILE THE UPPER FLOW FLATTENS. MINIMUM RELATIVE HUMIDITIES GENERALLY AT OR AROUND 20 PERCENT AND 20 FOOT WINDS UNDER 25 KNOTS WILL PRECLUDE ANY CRITICAL FIRE WEATHER CONDITIONS THROUGH THE END OF THE WEEK. CLK && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 10/02 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AMARILLO TX 336 PM CDT SUN OCT 5 2008 .DISCUSSION... MAIN FORECAST CONCERN CONTINUES TO CENTER ON STRONG UPPER TROUGH WEST OF THE AREA. BASE OF STRONG UPPER TROUGH WAS OVER WESTERN NEW MEXICO THIS AFTERNOON WITH STRONG HEIGHT FALLS AND UPPER JET STREAK ROUNDING THE BASE OF THE TROUGH. SYNOPTIC SCALE ASCENT HAS LEAD TO WIDESPREAD SHOWERS/THUNDERSTORMS ACROSS MUCH OF EASTERN NEW MEXICO/WESTERN TEXAS TODAY. ALTHOUGH WIDESPREAD CLOUDS/RAIN OVER THE PANHANDLES HAS RESULTED IN LIMITED SURFACE HEATING/MID LEVEL LAPSE RATES...CONVECTION IS STILL POSSIBLE THIS EVENING. HOWEVER FURTHER WEST...LESS CLOUD COVER HAS RESULTED IN GREATER POTENTIAL FOR SEVERE STORMS WITH RUC MESOSCALE ANALYSIS INDICATING SBCAPES AROUND 1000 J/KG. SYSTEM WILL CONTINUE TO PUSH EAST TONIGHT AND WITH LIFT STILL MAXIMIZED AHEAD OF MAIN UPPER CIRCULATION...PRECIP WILL LAST INTO MONDAY. UPPER TROUGH MOVES OVER THE PANHANDLES MONDAY MORNING AND LIFTS INTO CENTRAL KANSAS DURING THE AFTERNOON WITH THE SURFACE LOW FOLLOWING A SIMILAR ROUTE. MID LEVEL MOISTURE WRAPPING AROUND THE MAIN UPPER CIRCULATION WILL SUPPORT WRAP AROUND SHOWERS AND ISOLATED THUNDERSTORMS DURING THE DAY. PRECIP WILL END FROM WEST TO EAST DURING THE DAY WITH THE BULK OF ANY SHOWERS/CONVECTION ENDING BY LATE AFTERNOON. LOW CLOUDS WILL BE SLOW TO DEPART...WHICH WILL LIKELY LEAD TO TEMPS ONLY CLIMBING INTO 70S WITH PERHAPS COOLER 60S FARTHER NORTH WHERE THE BETTER POTENTIAL FOR WRAP AROUND SHOWERS LIE. UPPER LEVEL HEIGHTS WILL BE SLOW TO RISE ACROSS THE HIGH PLAINS TUESDAY. HOWEVER AS THE UPPER TROUGH LIFTS INTO THE LOWER GREAT LAKES WEDNESDAY...THE UPPER LEVELS WILL TRANSITION TOWARD MORE OF A ZONAL FLOW REGIME. TUESDAY WILL ONCE AGAIN SEE TEMPS IN THE 70S AS SURFACE HIGH PRESSURE BUILDS INTO THE PLAINS. BUT AS THIS HIGH SLIDES SOUTHEAST OF THE AREA...SURFACE TROUGH WILL DEVELOP IN THE LEE OF THE ROCKIES. WITH THE SURFACE GRADIENT TURNING MORE OUT OF THE SOUTH...LOW LEVEL WARM AIR ADVECTION WILL BE MORE PRONOUNCED AND WILL LEAD TO TEMPS CLIMBING INTO THE UPPER 70S/LOWER 80S. ATTENTION THEN TURNS TO NEXT UPPER TROUGH THAT IS SLATED TO DROP SOUTH...INTO THE NORTHERN PLAINS BY THE END OF THE WEEK. MEDIUM RANGE MODELS DISPLAY TIMING AND TRACKING DISCREPANCIES ALTHOUGH STILL LOOKS LIKE THIS SYSTEM WILL BRING THE FIRST SIGNIFICANT COLD AIR INTRUSION TO THE AREA BY SUNDAY ALONG WITH THE NEXT POSSIBILITY OF PRECIP. CLK && .FIRE WEATHER... HIGH RELATIVE HUMIDITIES AND MODERATE RAINFALL TODAY WILL HELP ALLEVIATE ANY CRITICAL FIRE WEATHER CONDITIONS FOR A LITTLE WHILE. DRY AND WARMER AIR WILL MOVE INTO THE PANHANDLES FOR MUCH OF THE WEEK AS THE UPPER TROUGH HEADS INTO THE LOWER GREAT LAKES REGION WEDNESDAY WHILE THE UPPER FLOW FLATTENS. MINIMUM RELATIVE HUMIDITIES GENERALLY AT OR AROUND 20 PERCENT AND 20 FOOT WINDS UNDER 25 KNOTS WILL PRECLUDE ANY CRITICAL FIRE WEATHER CONDITIONS THROUGH THE END OF THE WEEK. CLK && .PRELIMINARY POINT TEMPS/POPS... AMARILLO TX 54 72 46 73 48 / 50 20 5 5 5 BEAVER OK 57 68 48 73 46 / 70 60 20 5 5 BOISE CITY OK 52 70 44 71 43 / 40 30 20 5 5 BORGER TX 58 74 51 74 52 / 50 40 5 5 5 BOYS RANCH TX 55 75 48 76 47 / 50 20 5 5 5 CANYON TX 53 75 46 74 45 / 50 20 5 5 5 CLARENDON TX 57 72 49 75 51 / 70 30 5 5 5 DALHART TX 51 68 44 73 44 / 40 30 5 5 5 GUYMON OK 55 69 46 72 44 / 60 40 20 5 5 HEREFORD TX 52 74 46 75 46 / 50 20 5 5 5 LIPSCOMB TX 60 68 49 72 47 / 80 60 20 5 5 PAMPA TX 58 70 50 71 53 / 50 40 10 5 5 SHAMROCK TX 59 71 53 75 51 / 80 50 10 5 5 WELLINGTON TX 60 73 53 77 52 / 90 50 10 5 5 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...NONE. OK...NONE. && $$ 01/05 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LA CROSSE WI 302 PM CDT SUN OCT 5 2008 .SHORT TERM...TONIGHT THROUGH WEDNESDAY NIGHT FORECAST FOCUS IS ON CLOUDS AND RAIN CHANCES TONIGHT...THEN RAIN CHANCES AGAIN MONDAY NIGHT AND TUESDAY. 17Z SURFACE ANALYSIS SHOWS WARM FRONT EXTENDING FROM SOUTH DAKOTA... THROUGH WESTERN IOWA AND INTO SOUTHERN ILLINOIS. RADAR SHOWING A BAND OF SHOWERS EXTENDING FROM CENTRAL MINNESOTA...INTO CENTRAL AND SOUTHEAST WISCONSIN. VISIBLE SATELLITE IMAGERY SHOWING BACK EDGE OF CLOUDS MOVING THROUGH SOUTHEAST MINNESOTA AND SOUTHWEST WISCONSIN. HOWEVER...FARTHER WEST STRATO CUMULUS CLOUDS WERE FILLING IN RATHER QUICKLY ACROSS WESTERN AND CENTRAL IOWA. 05.12Z MODELS IN DECENT AGREEMENT THROUGH THE PERIOD. IN THE NEAR TERM...RUC SHOWING FRONTOGENETIC FORCING IN THE 600MB-700MB LAYER TO CONTINUE TO LIFT NORTH THIS EVENING TAKING BAND OF SHOWERS WITH IT. KEPT HIGHER POPS ACROSS THE FAR NORTH THIS EVENING IN ZONE OF STRONGER FORCING. THE CLEARING TREND WILL BE SHORT LIVED THIS EVENING AS SOUNDINGS INDICATE CLOUDS TO FILL IN RATHER QUICKLY THIS EVENING ACROSS THE AREA AS LOW LEVELS REMAIN MOIST. ON MONDAY AREAS WILL BE BETWEEN TWO SYSTEMS. ALTHOUGH MODELS SHOWING SOME WEAK 850-700MB QG CONVERGENCE DURING THE MORNING HOURS...HAVE KEPT LOW END POPS ACROSS THE WEST AND NORTH DURING THE MORNING HOURS. NEXT TROUGH/SURFACE COLD FRONT CROSSES THE PLAINS LATE MONDAY AFTERNOON AND HEADS TOWARD THE AREA MONDAY NIGHT AND TUESDAY. BOTH NAM AND GFS CONSISTENT IN TAKING DEEP LAYER FORCING/LIFT ACROSS THE AREA LATE MONDAY NIGHT AND TUESDAY. ONLY MADE SOME MINOR CHANGES TO THE POP/WEATHER GRIDS IN THIS TIME FRAME WITH LIKELY POPS GOING WITH THE FRONTAL PASSAGE. SYSTEM SLOWLY PULLS AWAY TUESDAY NIGHT AND WEDNESDAY...BUT STILL CLOSE ENOUGH TO WARRANT LOW END POPS IN THIS TIME FRAME PER PREVIOUS GRIDDED DATABASE. AS FOR TEMPERATURES...MAV NUMBERS LOOK REASONABLE ALTHOUGH MAY BE A LITTLE ON THE WARM SIDE MONDAY AFTERNOON AND HAVE UNDERCUT A LITTLE. THESE WARMER TEMPERATURES WILL BE HIGHLY DEPENDANT ON AMOUNT OF SUNSHINE. .LONG TERM...THURSDAY THROUGH SUNDAY CONFIDENCE RATHER LOW IN THIS TIME FRAME AS MODELS CONTINUE TO SHOW PATTERN SHIFT AS WE HEAD INTO NEXT WEEKEND. ZONAL FLOW TO PERSIST AT THE BEGINNING OF THE PERIOD WITH HIGH PRESSURE OVERHEAD THURSDAY. AS THE HIGH SIDES EAST FRIDAY MODELS BEGIN TO DIVERGE ON HOW FAST SOUTHERLY FLOW RE-ESTABLISHES ITSELF ACROSS THE REGION. GFS SHOWS WARM ADVECTION/LIFT ACROSS THE AREA...WHILE ECMWF KEEPS THIS AREA FARTHER WEST. EVEN IN THE GFS LIFT IS WEAK AND THUS HAVE PULED POPS OUT FOR FRIDAY. FLOW THEN BECOMES MORE AMPLIFIED SATURDAY AND SUNDAY AS LARGE TROUGH DIGS ACROSS THE WESTERN CONUS. 05.00Z ECMWF DEEPER AND SLOWER WITH THIS FEATURE VERSUS THE 05.06Z GFS. IN FACT ECMWF SHOWING 500MB HEIGHTS 4 TO 6 STANDARD DEVIATIONS BELOW CLIMATOLOGICAL NORMAL ACROSS THE INTER MOUNTAIN WEST. ECMWF APPEARS TO THE OUTLIER WITH THIS SCENARIO AND THUS CONCUR WITH NCEP DISCUSSION OF A BLENDED APPROACH FOR DAYS 6 AND 7. && .AVIATION...TONIGHT AND MONDAY THE WARM FRONT ACROSS IA WILL CONTINUE TO LIFT NORTH TONIGHT AND MONDAY. THE FORCING AND LIFT WITH THIS FRONT WILL CONTINUE TO MOVE NORTH OF THE TAF SITES...WITH RATHER SMALL -SHRA CHANCES AT THE TAF SITES TONIGHT/MON. OF BIGGER CONCERN IS LOWER LEVEL MOISTURE SPREADING NORTH TONIGHT. THIS MOISTURE ALREADY MANIFESTING ITSELF AS SCT-LOCALLY BKN MVFR CLOUDS/CIGS WEST OF THE AREA. AS THE AIRMASS COOLS TONIGHT AND THE LOW LEVEL MOISTURE CONTINUES TO PUSH NORTH AND EAST...MVFR/LOCAL IFR CIGS AND MVFR VSBYS IN BR EXPECTED LATER TONIGHT INTO MID MORNING MON. WITH SOME INCREASE OF LOW LEVEL WINDS AND DEEPER MIXING...THESE CIGS/VSBYS EXPECTED TO IMPROVE BY LATE MON MORNING AND FOR THE AFTERNOON. CIGS/VSBYS EXPECTED TO DECREASE AGAIN LATE MON NIGHT/TUE AS A SFC AND MID LEVEL TROUGH WITH LIFT/MOISTURE AND HIGHER RAIN/ISOLATED TSRA CHANCES MOVES EAST ACROSS THE REGION. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...NONE. MN...NONE. IA...NONE. && $$ SHORT/LONG TERM...RABERDING AVIATION..........RRS wi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 530 AM EDT TUE OCT 7 2008 .SYNOPSIS... 09Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED AN UPR TROUGH OVER THE NRN/CENTRAL PLAINS WITH RIDGING OVER THE GREAT LAKES. A PLUME OF MOISTURE AND FORCING AHEAD OF THE UPR TROUGH SUPPORTING AN AREA OF PCPN FROM THE SRN PLAINS THROUGH IA AND MN. PRECIPITABLE WATER PLOT INDICATING VALUES OF AROUND 1.3 INCHES ALONG THE AXIS OF SHOWER ACTIVITY. && .DISCUSSION... TODAY...MODELS SEEM TO BE TRENDING SLOWER YET WITH ADVANCE OF UPR TROUGH APPROACHING FROM THE NRN PLAINS. THIS IS LIKELY DUE TO THE PROMINENT RIDGING IN PLACE OVER THE WRN GREAT LAKES. THE RIDGE IS FCST TO GRADUALLY MOVE EAST TODAY WITH THE ADVANCE OF THE UPR TROUGH ALLOWING FOR THE SFC TROUGH TO MOVE INTO THE FAR WRN PORTION OF THE CWA. GIVEN THE HIGH PCPN WATER VALUES OF OVER AN INCH MOVING IN ALONG/AHEAD OF THE SFC TROUGH...DECIDED TO KEEP LIKELY POPS IN FOR THE FAR WEST THIS AFTERNOON BUT TRIMMED BACK POPS TO SLIGHT CHC OVER WRN MQT...DICKINSON AND MNM COUNTIES LATE. NOT SURE HOW WELL WE WILL MIX TODAY GIVEN THICKENING OF HIGH CLOUDS FROM THE WEST AND PREVAILING SE FLOW...BUT DECIDED TO FAVOR SLIGHTLY WARMER MET GUIDANCE WHICH IS ALSO IN LINE WITH GOING FCST OF 60-65F. SNDGS INDICATE EVEN IF WE MIX TO JUST OVER 900MB...WE SHOULD BE ABLE TO REACH INTO THE LOWER 60S TO MID 60S. WARMEST READINGS CAN BE EXPECTED IN DOWNSLOPE SE FLOW AREAS... WITH COOLEST READINGS DOWNWIND OF LAKE MICHIGAN. TONIGHT...THE MID LEVEL TROUGH AND SFC TROUGH COME MORE INTO PHASE AS THEY MOVE THROUGH THE REGION TONIGHT. DPVA AHEAD OF THE UPR TROUGH AND A BROAD AREA OF 300-305K ISENTROPIC LIFT WILL COMBINE WITH STRONG MOISTURE INFLOW (PWAT VALUES OF 1.00-1.25 INCHES) TO SUPPORT DECENT COVERAGE OF RAIN. KEPT LIKELY POPS OVER MUCH OF THE FCST AREA. WED INTO THU...ANY LEFTOVER RAIN IS EXPECTED TO DEPART THE EAST HALF OF THE CWA WED MORNING. MODELS THEN INDICATE A MORE ZONAL FLOW PATTERN WITH A MID LEVEL LOW AND SFC TROUGH MOVING THROUGH NRN MANITOBA INTO NW ONTARIO AND A DRY WRLY FLOW OVER THE UPR GREAT LAKES. && .AVIATION (FOR THE 06Z TAF ISSUANCE)... VFR CONDITIONS WILL CONTINUE AT KCMX THROUGH THE PERIODS WITH LLW OVERNIGHT. LOW CLOUDS TO THE SOUTH WILL NOT MAKE IT INTO KCMX DUE TO SE WINDS WHICH IS DOWNSLOPE FOR THEM.ADDED RAIN IN LATER IN THE AFTERNOON AND LLWS MON NIGHT. KSAW IS TRICKIER AND CONFIDENCE CONTINUES TO BE LOW AT THAT SITE BASED ON WHAT HAPPENED EARLIER TONIGHT. LOW CIGS EARLIER WERE TEMPORARILY CAUSED BY RAIN AND ALSO A BIT OF UPSLOPE. THESE LOW CLOUDS ERODED AWAY AND THEN KESC WHICH IS UPSTREAM WITH SOUTHERLY FLOW HAD FOG AND LOW CLOUDS FORMED AND THEN DISSIPATED AS THE WINDS PICKED UP THERE. SOUTH WINDS AT KSAW ARE UPSLOPE AND WITH KESC HAVING FOG EARLIER WITH A VLIFR CIG AND VIS...THINK MOISTURE FROM LAKE MICHIGAN COULD COME INTO PLAY THIS FORECAST AND STARTED OFF WITH MVFR VIS AND THEN TEMPO IFR VIS AND LIFR CIG WHICH SHOULD BE IN PLACE AT SUNRISE. KSAW IS TRYING TO GET SOME FOG OR LOW STRATUS TO FORM AS VIS HAS DROPPED TO 7 NOW...SO ONLY A MATTER OF TIME BEFORE THINGS DROP OFF. WILL GO MORE PESSIMISTIC WITH THIS FORECAST WITH LAKE MICHIGAN FOG/STRATUS POSSIBILITY OVERNIGHT. AFTER SUNRISE...CONDITIONS SHOULD BE BACK TO VFR AND LAST THROUGH THE REST OF THE PERIOD WITH SHOWERS LATE IN THE PERIOD. LLWS OVERNIGHT AT KSAW ALSO. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... A TIGHT PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER EASTERN ONTARIO AND A FRONTAL SYSTEM OVER WESTERN MINNESOTA ARE CREATING NBREEZY SOUTHEAST WINDS WHICH WILL CONTINUE ON LAKE SUPERIOR TODAY... ESPECIALLY ON THE EAST HALF WHERE WINDS GUST SPEEDS OF UP TO 30 KT ARE POSSIBLE. AS THE FRONT MOVES INTO FAR WESTERN LAKE SUPERIOR LATE THIS AFTERNOON AND CROSS THE REST OF THE LAKE TONIGHT INTO WEDNESDAY MORNING...WINDS SHOULD FALL BELOW 20 KT AND GRADUALLY SHIFT TO THE SOUTHWEST. DEEPENING LOW PRESSURE SYSTEM WILL CROSS CENTRAL CANADA TO HUDSON BAY WEDNESDAY THROUGH THURSDAY AS HIGH PRESSURE CROSSES THE SOUTHERN GREAT LAKES CAUSING AN INCREASING WEST WIND OVER LAKE SUPERIOR...POSSIBLY REACHING UP TO 30 KNOTS WEDNESDAY NIGHT AND THURSDAY ACROSS THE NORTHERN PORTION OF THE LAKE. THE HIGH PRESSURE AREA OVER THE SOUTHERN GREAT LAKES SHOULD EXPAND UP INTO THE LAKE SUPERIOR ON FRIDAY BRINGING WINDS DOWN BELOW 20 KT. AS THE FRONTAL BOUNDARY SET UP OVER THE UPPER GREAT LAKES FRIDAY NIGHT AND SATURDAY SOUTHEAST WINDS UP TO 25 KT MAY AFFECT LAKE SUPERIOR DURING THIS PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE LAKE MICHIGAN...NONE. && $$ SYNOPSIS/DICUSSION...VOSS AVIATION...GM MARINE...DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 147 AM CDT TUE OCT 7 2008 .SYNOPSIS... A STRONG UPPER LOW WAS CURRENTLY ACROSS SOUTHEAST NEBRASKA WITH A TRAILING COLD/COOL (AIR MASS) FRONT ACROSS EASTERN KANSAS. RADAR TRENDS MONDAY EVENING AND EARLY THIS MORNING HAVE THE BULK OF THE HEAVIEST RAINFALL AND CONVECTION ACROSS SOUTHERN ARKANSAS. EARLIER THIS EVENING...A BAND OF HEAVY RAINFALL ASSOCIATED WITH ONE OF THE STRONGER COMPLEXES ACROSS EASTERN OKLAHOMA/WESTERN ARKANSAS LED TO RAINFALL AMOUNTS OF ONE HALF TO LOCALLY ONE INCH SOUTH AND SOUTHWEST OF THE SPRINGFIELD AREA. AS OF 1 AM...THE BULK OF THE HEAVIEST RAINFALL HAS SHIFTED SOUTHEAST OF SPRINGFIELD...AND MAINLY AFFECTING AREAS OF WEST PLAINS...ALTON AND EMINENCE. WATER VAPOR AND RUC ANALYSIS STILL SHOWING EMBEDDED SHORT WAVES ACROSS KANSAS AND NORTHERN OKLAHOMA. JLT && .DISCUSSION... AS THE STRONGEST MOISTURE ADVECTION REMAINS SOUTH OF THE REGION...HAVE OPTED TO DECREASE PERCENTAGES TO LIKELY EAST OF SPRINGFIELD...TO SCATTERED WEST OF SPRINGFIELD. HOWEVER...UPPER LEVEL DYNAMICS ASSOCIATED WITH THE UPPER LOW AND WEAK ISENTROPIC LIFT AND AFTERNOON INSTABILITY OF THE COLD POOL...WILL LIKELY CONTRIBUTE TO ADDITIONAL PRECIPITATION LATER TODAY. WILL LIKELY HOLD OFF UNTIL DAWN TO ADJUST THE MAIN PRECIPITATION AREA THIS MORNING...WITH SCATTERED ACTIVITY THIS AFTERNOON. WILL KEEP ISOLATED/SCATTERED SHOWERS ACROSS THE FAR EASTERN FORECAST AREA THIS EVENING AS THE MAIN UPPER TROUGH REMAINS NEAR THE REGION. THERE SHOULD BE A VERY SHARP CUT OFF LATER TONIGHT WITH THE CLOUD COVER DECREASING RAPIDLY FROM WEST TO EAST. FOG POTENTIAL IS LIKELY WEDNESDAY MORNING WITH CLEAR SKIES/LIGHT WINDS AND RESIDUAL MOISTURE NEAR THE SURFACE. DENSE FOG ADVISORY MAYBE CONSIDERED FOR THE NEXT MIDNIGHT SHIFT. THE EXTENDED OUTLOOK REMAINS VERY ACTIVE ACROSS THE ROCKIES AND NORTHERN PLAINS. ALL MODELS INDICATED THAT A VERY DEEP SYNOPTIC SCALE LOW AND LONG WAVE TROUGH DEVELOPING ACROSS THE WESTERN U.S. LATEST GFS HAS THE MAIN CORE AS FAR SOUTH AS THE FOUR CORNERS AREA OF THE SOUTHWESTERN U.S. THIS WILL LED TO A VERY WARM PATTERN ACROSS THE CENTRAL U.S. WITH MAINLY DRY CONDITIONS. ONCE THIS SYSTEM BEGINS TO MOVE EASTWARD...A VERY ACTIVE WEATHER PATTERN WILL EVOLVE ACROSS OUR REGION. JLT && .AVIATION... FOR THE 06Z TAFS...EXPECT CEILINGS TO BUILD DOWN TO AT LEAST MVFR LEVELS BY 12Z...WITH SPRINGFIELD LIKELY SEEING IFR FOR THE FIRST SEVERAL HOURS AFTER SUNRISE. HAVE TIMED PRECIP BASED ON RADAR AND MOVEMENT OF THE FRONT...WITH THE MOST LIKELY TIME FOR RAIN AT THE AIRPORTS ALSO CENTERED AROUND THE 10-15Z TIME FRAME. UPSLOPE FLOW BEHIND THE FRONT COULD KEEP LOWER CEILINGS AND VISIBILITIES OVER THE OZARKS A LITTLE LONGER THAN THE GOING FORECAST INDICATES. ALSO WILL HAVE TO MONITOR WIND SPEEDS LATE IN THE FORECAST AS THEY MAY BE A LITTLE ON THE LIGHT SIDE. TERRY && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 427 AM CDT TUE OCT 7 2008 .DISCUSSION...THE TAIL END OF A CENTRAL U.S. STORM SYSTEM WILL APPROACH FROM THE NORTHWEST THIS MORNING. THE FRONT NOW CURVES NORTHEAST TO SOUTHWEST ACROSS EAST AND SOUTH CENTRAL TEXAS. THE BASE OF THE ASSOCIATED H5 TROUGH WILL SWING ACROSS ARKANSAS TODAY...WELL NORTH OF HERE...DIMINISHING THE THREAT FOR STRONGER WEATHER AS THE FRONT EVENTUALLY MOVES THROUGH. FOG IS SETTING UP AROUND DEEP SOUTH TEXAS THIS MORNING AS MOISTURE POOLS AHEAD OF THE FRONT AND WINDS REMAIN LIGHT. HIGH PRESSURE WILL PUSH SOUTHEAST FROM THE FOUR CORNERS INTO WEST TEXAS AND THEN SOUTHEAST AND SOUTH TEXAS TODAY. THE SURFACE FRONT SHOULD PUSH INTO DEEP SOUTH TEXAS BY THIS EVENING...MOVING THROUGH THE AREA OVERNIGHT. THE BEST CHANCE FOR SHOWERS AND THUNDERSTORMS WILL BE THIS AFTERNOON AND EVENING AS THE FRONT APPROACHES. GENERAL THUNDERSTORM CONDITIONS ARE FORECAST BY SPC FOR TODAY AND TONIGHT. MASSAGED THE POPS IN THE INHERITED FORECAST WITH A MODEL BLEND... BUT THAT EFFORT DID NOT RESULT IN MUCH CHANGE...AND THE FORECAST IS STILL SHOWING CHANCE CATEGORY FOR MOST AREAS TODAY AND TONIGHT. THE WEATHER WILL CLEAR RAPIDLY AFTER DAYBREAK TOMORROW ONCE THE FRONT IS THROUGH...WITH LIGHT NORTHEAST WINDS AND SUNNY SKIES. THE NORTHWEST MID LEVEL FLOW AND SURFACE HIGH PRESSURE WILL DRY THINGS OUT AND PRODUCE FAIR AUTUMN WEATHER FOR A FEW DAYS. COOLER THAN NORMAL OVERNIGHT TEMPERATURES ARE EXPECTED WEDNESDAY NIGHT...BUT TEMPS WILL OTHERWISE NOT BE ALTERED SIGNIFICANTLY AS A RESULT OF THE FRONT. ANOTHER H5 SHORT WAVE TROUGH WILL DIG INTO THE PACIFIC NORTHWEST ON THURSDAY...KICKING OFF A CHAIN OF EVENTS THAT WILL LEAD TO ANOTHER FRONTAL PASSAGE LATE IN THE FORECAST. A LOW PRESSURE SYSTEM WILL DEVELOP IN THE LEE OF THE ROCKIES IN COLORADO AHEAD OF THE H5 TROUGH...AND ALONG WITH HIGH PRESSURE IN THE NORTH GULF...WILL SET UP RETURN SOUTHEAST FLOW BY THURSDAY NIGHT. MEANWHILE...HIGH PRESSURE WILL STRENGTHEN OVER THE SOUTHEAST UNITED STATES...LEADING TO A DELAY IN THE ARRIVAL OF THE NEXT FRONT...WHICH WAS ORIGINALLY SCHEDULED FOR SUNDAY. NONETHELESS... SHOWERS ARE STILL POSSIBLE OVER THE WEEKEND AS RETURN FLOW BRINGS MOISTURE AND EVEN AN OLD FRONTAL BOUNDARY BACK NORTH. A MAJOR H5 LOW AND STORM SYSTEM WILL GET HUNG UP OVER UTAH LATE IN THE WEEKEND...BUT WILL BEGIN TO EJECT NORTHEAST OVER THE NORTHERN PLAINS SUNDAY AND MONDAY. THE HIGH PRESSURE BEHIND IT WILL THEN BE RELEASED AND WILL BE PUSHED SOUTHEAST EARLY IN THE WEEK. A WEAKER FRONT THAN FORECAST PREVIOUSLY WILL THEN APPROACH NEXT TUESDAY AND WILL MOVE THROUGH TUESDAY NIGHT. && .PREV DISCUSSION... /ISSUED 743 PM CDT MON OCT 6 2008/ RUC80 500MB HEIGHT ANALYSIS INDICATED A TROUGH ACROSS THE CENTRAL AND SOUTHERN PLAINS THIS EVENING. MSAS SURFACE ANALYSIS INDICATED A WEAK COLD FRONT FROM NORTH TEXAS EXTENDING BACK TO PORTIONS OF WEST TX. SATELLITE AND RADAR IMAGES INDICATE CONVECTION CONTINUE TO DEVELOP ACROSS NORTHEAST TX. WARMER 850MB TEMPERATURES ACROSS SOUTH TX APPEAR TO KEEP THE ATMOSPHERE CAPPED ACROSS THE RIO GRANDE PLAINS AND THE LOWER RIO GRANDE VALLEY. 18Z NAM PROGS CONVECTION DEVELOPING ACROSS CENTRAL TX TONIGHT AND MOVING TOWARDS SOUTHEAST TX TUESDAY MORNING. THE FRONTAL BOUNDARY IS EXPECTED TO REACH THE COASTAL BEND TUES AFTERNOON. SHOWERS AND THUNDERSTORMS MAY DEVELOP AS THE FRONT MOVES INTO THE CWA. WILL LIKELY REMOVE POPS TONIGHT AND LOWER POPS TUES MORNING UNTIL THE 850MB FRONT ERODES THE CAP ACROSS DEEP SOUTH TX LATE TUES MORNING OR EARLY TUES AFTERNOON. && .MARINE...BUOY 42020 REPORTED SOUTHEAST WINDS AROUND 10 KNOTS GUSTING TO AROUND 14 KNOTS WITH SEAS SLIGHTLY UNDER 5 FEET WITH A PERIOD OF 8 SECONDS AT 01 CDT/06 UTC. LIGHT WINDS AND MODERATE SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST TODAY AND TONIGHT AHEAD OF A COLD FRONT...WHICH WILL SWEEP THROUGH THE LOWER TEXAS COAST AROUND SUNRISE WEDNESDAY MORNING. WINDS AND SEAS WILL INCREASE IN THE WAKE OF THE FRONT...BUT SMALL CRAFT ADVISORY CONDITIONS ARE NOT EXPECTED AT THIS TIME. LIGHT TO MODERATE WINDS AND LOW TO MODERATE SEAS WILL THEN PREVAIL WEDNESDAY NIGHT THROUGH THE WEEKEND WITH WEAK SURFACE HIGH PRESSURE OVERHEAD. && .AVIATION...SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER DEEP SOUTH TEXAS TODAY AND TONIGHT IN ADVANCE OF A COLD FRONT...WHICH WILL SWEEP THROUGH THE REGION AROUND SUNRISE WEDNESDAY MORNING. VFR/MVFR CONDITIONS WILL PREVAIL THROUGH THE NEXT 24 HOURS. && .HYDRO...THE RIO GRANDE RIVER AT THE SAN BENITO GAGE WILL CONTINUE TO RISE AS MORE WATER IS RELEASED UPSTREAM. CRESTING IS FORECAST AT 7 AM CDT ON SATURDAY. SEE THE LATEST SATRVSBRO FOR MORE INFO. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 90 73 86 65 / 50 30 0 0 BROWNSVILLE 91 70 87 63 / 50 30 10 0 HARLINGEN 91 70 88 62 / 50 30 0 0 MCALLEN 93 71 89 62 / 40 30 10 0 RIO GRANDE CITY 93 68 92 63 / 20 40 10 0 SOUTH PADRE ISLAND 88 76 85 70 / 50 30 0 0 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WWW.WEATHER.GOV/BROWNSVILLE 54/66 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 1207 AM CDT TUE OCT 7 2008 .AVIATION... BOTTOM EDGE OF A SQUALL LINE IS BEING INTERFERED WITH BY A SEA BREEZE SO IS TEMPERORARILY BREAKING UP INTO SCATTERED CELLS OVER A BROADER AREA OVER THE EASTERN HILL COUNTRY. THIS COULD RESULT IN A LONGER IMPACT ON THE AUS TERMINAL AND COULD RESULT IN LESS FOCUSING AND COVERAGE FOR THE SAT METRO AREA TERMINALS. COLD FRONT IS MAKING GOOD PROGRESS TOWARD THE DRT AREA, AND LOOKS TO PASS THROUGH DRT BETWEEN 9 AND 10Z AND INTO AUS BY 11Z AND SAT BY 12Z. BY 14Z, NEARLY ALL AREAS SHOULD SEE VFR CONDITIONS TO CARRY THROUGH THE END OF THE TAF PERIOD. SOME EXTRA WINDS WERE ADDED FOR THE MIDDLE OF THE DAY DUE TO INCREASING MOS WIND TRENDS && .PREV DISCUSSION... /ISSUED 848 PM CDT MON OCT 6 2008/ UPDATE...PROBABILITIES WERE RECONFIGURED FROM NOW TIL MIDNIGHT AS A SUBSIDENT SOUTHWEST TO WEST FLOW ALOFT WAS LIMITING DEVELOPMENTS. NEW RAOB DATA FROM KDRT AND KCRP REINFORCE IDEA AND POINT TO SEVERAL INVERSIONS IN THE LOW AND MID LEVELS AS TEMPERATURES HAD INCREASED AND MOISTURE DECREASED IN THE ZONE OF SOUTH-WESTERLIES ALOFT. AFTER MIDNIGHT..PROBABILITIES STILL ON TRACK AS LATEST RUC SHOWS LAST DISTURBANCE PUSHING TROUGH THROUGH EASTERN CWA INTO RICHER MOISTURE FIELD. THIS WILL DESTABILIZE UPPER LEVELS AT THE SAME TIME LOWERING SUBSIDENT SOUTHWEST WIND INFLUENCE. THUS..ACTIVITY SHOULD FORM AGAIN..MAINLY EAST OF THE I-35 CORRIDOR LATE TONIGHT. PREV DISCUSSION... /ISSUED 302 PM CDT MON OCT 6 2008/ DISCUSSION... THIS AFTERNOON ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WERE DEVELOPING ACROSS OUR NORTHEAST COUNTIES IN THE WARM AND UNSTABLE AIRMASS...IN ADVANCE OF THE DRY LINE AND COLD FRONT. THE PRE-FRONTAL TROF/DRY LINE IS EAST OF K6R6 AND KSJT WITH THE COLD FRONT HAVING PASSED THROUGH KINK AND KLBB. THE BEST LOW LEVEL CONVERGENCE WILL OCCUR ALONG AND AHEAD OF THE FRONTAL BOUNDARY ALONG AND EAST OF HIGHWAY 281 WHERE THE BEST LOW LEVEL MOISTURE AXIS IS LOCATED. THUS THE BEST CHANCE FOR MEASURABLE RAINFALL ASSOCIATED WITH THE FROPA WILL BE MAINLY EAST OF HIGHWAY 281. THE FRONTAL BOUNDARY WILL MOVE ACROSS OUR CWFA OVERNIGHT AND WILL CLEAR OUR SOUTHEAST COUNTIES TUESDAY MORNING. THERE WILL BE SOME POST- FRONTAL SHOWERS LINGERING ACROSS OUR SOUTHEAST COUNTIES TUESDAY AFTERNOON AS THE COLD FRONT CLEARS THE MIDDLE TEXAS COAST. HIGH PRESSURE AT THE SURFACE AND ALOFT WILL DOMINATE THE WEATHER ACROSS SOUTH CENTRAL TEXAS WEDNESDAY AND THURSDAY. THIS PATTERN WILL RESULT IN COOL MORNINGS AND WARM AFTERNOONS. GULF MOISTURE WILL BEGIN TO RETURN TO THE CWFA ON FRIDAY. ATMOSPHERIC MOISTURE LEVELS WILL INCREASE SATURDAY THRU MONDAY IN ADVANCE OF THE NEXT UPPER LEVEL TROF AND ASSOCIATED COLD FRONT. THUS A WET WEEKEND IS EXPECTED. ATTM THE NEXT COLD FRONT IS EXPECTED TO MOVE ACROSS SOUTH CENTRAL TEXAS MONDAY NIGHT OF NEXT WEEK. THE GFS HAS BEEN INCONSISTENT WITH THE TIMING OF THIS FRONT SO WENT WITH THE HPC DAY 7 GRAPHIC FOR FRONTAL TIMING. && .PRELIMINARY POINT TEMPS/POPS... AUSTIN CAMP MABRY 67 86 59 88 57 / 60 10 0 0 0 AUSTIN BERGSTROM INTL AIRPORT 66 86 54 86 52 / 60 10 0 0 0 DEL RIO INTL AIRPORT 68 88 59 87 58 / 10 - 0 0 0 SAN ANTONIO INTL AIRPORT 68 86 58 88 54 / 30 10 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ 02/18 tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOUISVILLE KY 1115 AM EDT TUE OCT 7 2008 .MORNING UPDATE... THE MESO-NAM AND ESPECIALLY THE RUC HAVE A GOOD HANDLE ON THE BROAD AREA OF SHOWERS AND EMBEDDED THUNDER NOW IN WESTERN KENTUCKY. THIS AREA OF RAIN HAS DEVELOPED VIA GOOD MOISTURE TRANSPORT AND LIFT ASSOCIATED WITH SOUTHERLY WINDS AHEAD OF A TROUGH. IN ADDITION...ELEVATED INSTABILITY HAS BEEN NOTED ACROSS WESTERN TENNESSEE. AGREE WITH THE RUC WHICH HAS THIS AREA OF RAIN WEAKENING WHILE MOVING SLOWLY EASTWARD. CURRENTLY...PRECIPITABLE WATER AND ELEVATED INSTABILITY ARE MUCH LOWER EAST OF INTERSTATE 65. EAST WINDS HAVE KEPT SURFACE DEWPOINTS ONLY IN THE UPPER 40S ACROSS THE BLUEGRASS AND LAKE CUMBERLAND REGIONS...ALTHOUGH THEY WILL RISE THIS AFTERNOON AS MOIST AIR MIXES DOWNWARD. UPDATED ZONES TO ACCOUNT FOR TIMING OF PRECIPITATION ONSET. OUR SOUTHWESTERN COUNTIES...INCLUDING BOWLING GREEN...SHOULD RECEIVE RAIN BY EARLY THIS AFTERNOON...WHILE AREAS NORTHEAST OF LOUISVILLE AND THE BLUEGRASS REGION WILL NOT SEE PRECIP UNTIL TOWARDS DARK. SOME AREAS IN WESTERN KENTUCKY HAVE RECEIVED AN INCH...BUT ADDITIONAL AMOUNTS WILL DROP THIS AFTERNOON AS THIS INITIAL BATCH OF SHOWERS WEAKEN. ADDITIONAL SHOWERS TONIGHT MAY STILL BRING WIDESPREAD RAINS TO THE WHOLE REGION. .SHORT TERM (TODAY AND TONIGHT)... MUCH NEEDED RAINFALL WILL BE LIKELY FROM LATE THIS AFTERNOON THROUGH THE OVERNIGHT HOURS AS A DEEP TROUGH AND LOW PRESSURE SYSTEM APPROACH THE AREA TODAY AND TONIGHT. CURRENTLY...UPPER LEVEL CLOUDINESS IS MOVING INTO THE AREA IN RESPONSE TO THIS SYSTEM. THE STORY FOR TODAY REMAINS MUCH THE SAME AS THE LAST FEW DAYS. CONDITIONS WILL REMAIN DRY THROUGH MIDDAY WITH AN INCREASING CHANCE FOR SHOWERS AND THUNDERSTORMS BY THIS AFTERNOON. INCREASED POPS IN THE EAST BETWEEN 18-00Z AS THUNDERSTORM CHANCES WILL INCREASE IN THE LATE AFTERNOON. CLOUDS WILL ALSO BE ON THE INCREASE DURING THIS TIME WITH MUCH OF THE AREA BECOMING CLOUDY BY THE AFTERNOON HOURS. THEREFORE...LOWERED TEMPERATURES A BIT AND EXPECT HIGHS IN THE FROM THE MID 70S TO NEAR 80 ACROSS THE AREA. WINDS MAY ALSO BE GUSTY TODAY AS THE PRESSURE GRADIENT INCREASES SOMEWHAT WITH HIGH PRESSURE TO OUR EAST AND LOW PRESSURE MOVING IN FROM THE WEST. WINDS INCREASING TO 20 TO 35 KT AT 925 AND 850 MB THIS AFTERNOON WILL ALSO AIDE IN SOME STRONGER SURFACE WINDS THROUGH EVENING. DO NOT EXPECT ANY THUNDERSTORMS THAT DEVELOP TO BE SEVERE TODAY AND HEAVY RAIN AT TIMES WILL BE THE MAIN CONCERN. THE BEST CHANCE FOR RAINFALL WILL BE TONIGHT AS UPPER TROUGH AND SURFACE LOW CONTINUE TO MOVE EASTWARD AND DIG. PLENTY OF GULF MOISTURE WILL HAVE BEEN STREAMING NORTHWARD DURING THE DAY AND MANY AREAS SHOULD SEE GOOD RAINFALL RATES...WITH DEEP SATURATED WARM CLOUD LAYERS...DESPITE THE RELATIVELY QUICK MOVEMENT OF THE SYSTEM. INCREASED POPS AND QPF AMOUNTS OVERNIGHT TO REFLECT CONFIDENCE IN FORECAST AND DUE TO THE ABOVE MENTIONED FACTS AS WELL AS MODEL GUIDANCE BEING IN VERY GOOD AGREEMENT. AS MENTIONED BEFORE...PERIODS OF MODERATE RAINFALL ARE EXPECTED AND SOME LOCATIONS MAY SEE UP TO THREE QUARTERS OF AN INCH OF PRECIPITATION BY WEDNESDAY MORNING. OVERNIGHT LOWS WILL REMAIN FAIRLY WARM DUE TO OVERCAST SKIES. EXPECT LOWS TO HOVER AROUND THE 60 DEGREE MARK IN MOST LOCATIONS. .LONG TERM (WEDNESDAY THROUGH COLUMBUS DAY)... A SHARP UPPER TROF LINED UP ALONG THE LENGTH OF THE MISSISSIPPI RIVER AT THE BEGINNING OF THE PERIOD WILL MOVE EAST TO THE SPINE OF THE APPALACHIANS BY THURSDAY MORNING WHILE DE-AMPLIFYING. AT THE SURFACE A WEAK COLD FRONT WILL PASS THROUGH THE REGION FROM WEST TO EAST WEDNESDAY AND WEDNESDAY NIGHT...THEN LOSE MUCH OF ITS IDENTITY TO OUR EAST ON THURSDAY. BY FAR THE BEST CHANCE OF RAIN IN THE LONG TERM WILL BE DURING THE DAY ON WEDNESDAY. THE GULF OF MEXICO WILL BE WIDE OPEN AND HIGH PRESSURE OFF THE VIRGINIA COAST COMBINED WITH LOW PRESSURE OVER MICHIGAN WILL DRAW THAT MOISTURE NORTHWARD INTO THE FRONTAL ZONE STRETCHED ACROSS OUR REGION. LOOKS LIKE GOOD SHOWER COVERAGE...ESPECIALLY WEDNESDAY MORNING. OVER THE COURSE OF THE DAY ON WEDNESDAY GENERAL RAINFALL AMOUNTS WILL LIKELY BE IN THE 1/4 TO 1/2 INCH RANGE...SIMILAR TO THE SYSTEM THAT MOVED THROUGH HERE ON THE 29TH AND 30TH OF SEPTEMBER. A FEW THUNDERSTORMS COULD DEVELOP BUT DYNAMICS WITH THE SYSTEM ARE FAIRLY WEAK. LATER IN THE WEEK AND INTO THE WEEKEND A STRONG UPPER TROUGH WILL DIG INTO THE AMERICAN WEST...BUILDING A RIDGE OVER THE EAST IN RESPONSE. AS A RESULT IT LOOKS LIKE WE WILL RETURN TO DRY WEATHER CONDITIONS. TEMPERATURES WILL MODERATE UNDER THE RIDGE WITH AFTERNOON HIGHS BY FRIDAY AND SATURDAY 5 TO 10 DEGREES WARMER THAN NORMAL. THANKS TO ILN...JKL...AND IND FOR COORD. && .AVIATION (12Z TAFS)... VFR CONDITIONS WILL PREVAIL TODAY THROUGH AT LEAST 18-21Z. THUNDERSTORM CHANCES WILL INCREASE AT BWG AND SDF AROUND THAT TIME AS A LOW PRESSURE SYSTEM AND COLD FRONT APPROACH THE AREA LATE THIS AFTERNOON AND TONIGHT. WHILE CEILINGS WILL REMAIN VFR THIS AFTERNOON...VISIBILITIES MAY BE REDUCED TO IFR OR MVFR IN ANY THUNDERSTORMS THAT DEVELOP. LATER THIS EVENING AND TONIGHT...SHOWERS AND ISOLATED THUNDERSTORMS WILL SPREAD EASTWARD. THIS ACTIVITY SHOULD REACH SDF BY 03-06Z AND LEX BETWEEN 06-09Z. LOCAL MVFR CEILINGS WILL BE POSSIBLE LATE TONIGHT WITH SOME AREAS DIPPING TO BKN-OVC AT 2-3 KFT AFTER 06Z. OTHERWISE...VISIBILITIES WILL BE THE MAIN ISSUE ONCE RAIN BEGINS AS IT MAY BE HEAVY AT TIMES. RIGHT NOW WENT WITH MVFR VISIBILITIES AT BWG AND SDF AND VFR AT LEX THROUGH THE TAF PERIOD...HOWEVER THESE COULD BE LOWER IF HEAVIER SHOWERS MOVE OVER TAF SITES. RAIN WILL LIKELY BE ONGOING OVER MOST OF THE AREA BY THE END OF THIS 24-HOUR TAF PERIOD. && WEATHER.GOV/LOUISVILLE .LMK WATCHES/WARNINGS/ADVISORIES... KY...NONE. IN...NONE. && $$ SHORT TERM...JSD LONG TERM....AL AVIATION.....JSD ky AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 1045 AM CDT TUE OCT 7 2008 .UPDATE...WATER VAPOR IMAGERY/RUC ANALYSIS SHOWS A SHORTWAVE TROUGH OVER KANSAS/OKLAHOMA THAT IS PROGGED TO STRENGTHEN TODAY AS IT MOVES SOUTHEAST. THIS WILL HELP THE COLD FRONT ANALYZED OVER EAST TEXAS CONTINUE TO APPROACH OUR CWA TODAY. ALTHOUGH MOST OF THE THUNDERSTORM ACTIVITY FROM EARLY MORNING HAS SHIFTED EAST OF OUR CWFA...SCATTERED SHOWERS CONTINUE OVER OUR EASTERN HALF. A LINE OF SHOWERS AND THUNDERSTORMS HAS FORMED OVER CENTRAL LOUISIANA WELL AHEAD OF THE COLD FRONT. THIS LINE WAS NEARING OUR LOUISIANA PARISHES AND WILL MOVE INTO SOUTHWEST MISSISSIPPI BY AFTERNOON. SPC HAS INCREASED RISK TODAY FOR SEVERE STORMS AND A FEW STRONG TO SEVERE THUNDERSTORMS MAY BECOME SEVERE THIS AFTERNOON OVER OUR WEST HALF. NOT SURE IF OUR EAST WILL RECOVER IN TIME BUT...BUT A FEW STRONG TO SEVERE STORMS MAY DEVELOP AS THE COLD FRONT MOVES IN THIS EVENING. GUIDANCE TODAY WAS TOO LOW ON POPS IN THE SOUTHWEST. HAVE GONE CATEGORICAL THERE BASED ON RADAR TRENDS. ADJUSTED TEMPS AS WELL AND UPDATES HAVE BEEN SENT. /22/ && .PREVIOUS DISCUSSION...SHORT TERM...DEEPER MOISTURE IS BEING ADVECTED INTO THE REGION TODAY. PRECIPITABLE WATER VALUES WERE RUNNING ABOVE 2 INCHES AT SLIDELL AT 00Z/07 AND ABOVE 1.5 INCHES TO THE WEST AND SOUTHWEST. A WAVE THAT LIFTED NEWD ACROSS THE ARKLAMISS LATE YDY/OVERNIGHT HELPED TO FOCUS CONVECTION WITH ONE OR TWO SEVERE STORMS EAST OF I-55 EARLY THIS MORNING. RAINFALL HAS PERSISTED JUST UPSTREAM ACROSS ARKANSAS TONIGHT...SHOWING VERY SLOW EWD MOVEMENT AS THE STRONGER ACTIVITY LIFTS N OF THE AREA. THE COLD FRONT WILL MOVE NEAR THE MS RIVER AROUND 00Z/08...MAINTAINING GOOD RAIN CHANCES ACROSS THE AREA. WITH SUCH DEEP MOISTURE IN PLACE...PERIODS OF HEAVY RAINFALL WILL OCCUR IN STRONGER STORMS. THE BETTER LOW LEVEL JET AND ASSOCIATED SHEAR WILL BE IN PLACE THIS MORNING BUT IS FORECAST TO WEAKEN THIS AFTERNOON WHEN 850 MB VEERS SLIGHTLY MORE WLY. HOWEVER FORCING ALONG AND JUST AHEAD OF THE BOUNDARY WILL BE SUFFICIENT TO MAINTAIN THE CHANCE OF STRONG CONVECTION INTO THE EVENING. RAIN CHANCES WILL CONTINUE TONIGHT WHEN THE COLD FRONT TRACKS THROUGH THE REGION. POPS WILL DECREASE FROM THE WEST LATE IN THE WAKE OF THE FRONT. /03/ LONG TERM...WEDNESDAY THROUGH TUESDAY. STUCK WITH GUIDANCE AGAIN TODAY. THE GFS CONTINUES TO DRY THE AREA OUT...HOPEFULLY THE FORECAST WILL NOT FLIP FLOP. POP VALUES DROPPED FROM 60 PERCENT TO 10 PERCENT FOR THE NORTHWEST PORTIONS OF THE CWA FOR THE WEEKEND. CONSIDERED USING A BLEND AND MAINTAINING LOW CHANCE VALUES JUST IN CASE THE SYSTEM SPEEDS UP. HOWEVER...THE EUROPEAN KEEPS THE AREA DRY AFTER WEDNESDAY. IT HAS BEEN CONSISTENTLY DRY FOR THE PAST FEW RUNS. TOOK RAIN OUT OF THE FORECAST FOR THE REMAINDER OF THE PERIOD. USED A BLEND OF GUIDANCE AND CLIMATOLOGY FOR TEMPS. RAISED HIGHS AND LOWS NEARLY EVERYDAY. THE BOUNDARY WILL BE EAST OF THE AREA BY WEDNESDAY AFTERNOON...WITH A FEW SHOWERS AND THUNDERSTORMS LINGERING OVER THE EASTERN ZONES. THE UPPER TROUGH WILL MOVE EVERYTHING OUT OF THE AREA...QUICKLY FOLLOWED BY COOL AND DRY AIR. A SURFACE HIGH WILL PASS THROUGH THE REGION THURSDAY AND FRIDAY. BY SATURDAY...AN UPPER LEVEL RIDGE WILL BUILD OVER THE EAST/SOUTHEAST STATES AND HELP KEEP MOISTURE AND RAIN TO THE WEST. THE RIDGE SEEMS TO HOLD THROUGH EARLY NEXT WEEK. RETURN FLOW BY THE WEEKEND WILL WARM THINGS UP...HIGHS MAY APPROACH 90 SUNDAY. BEYOND THE FORECAST PERIOD...THE MODELS NOW SUGGEST THE NEXT COLD FRONT WILL MOVE INTO THE AREA AROUND WEDNESDAY. GUIDANCE SHOWED SOME VERY SMALL RAIN CHANCES...BEING DAY 6 AND 7 OPTED TO KEEP THE AREA DRY. WILL LEAVE THE HWO CLEAR FOR THE EXTENDED. /07/ && .AVIATION...UPDATED WIDESPREAD MVFR CIGS WILL OCCUR ACROSS THE REGION THIS AFTERNOON. OCCASIONAL SHOWERS AND THUNDERSTORMS WILL CONTINUE WITH PERIODS OF FREQUENT LIGHTNING AND HEAVY RAINFALL. ISOLATED EPISODES OF DAMAGING THUNDERSTORM WIND GUSTS AND LARGE HAIL WILL BE POSSIBLE IN STRONGER STORMS. EXPECT THE STRONGEST STORMS TO AFFECT KGLH...KGWO...KJAN FOR THIS AFTERNOON...THEN AFFECT KGTR...KMEI AND KHBG SITES FOR TONIGHT. PUT IN WIND GUSTS OF 35G45KT AT TAF SITES WITH THE STRONGER STORMS. EXPECT WIDESPREAD MVFR CEILINGS FOR THE TAF PERIOD ACROSS THE WEST AND WIDESPREAD IFR CEILINGS ACROSS THE EAST HALF./17/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 83 60 78 57 / 75 44 7 0 MERIDIAN 79 62 79 55 / 84 60 21 0 VICKSBURG 84 59 79 54 / 62 28 3 1 HATTIESBURG 82 63 79 55 / 86 50 13 1 NATCHEZ 84 58 79 54 / 55 21 3 1 GREENVILLE 83 59 77 56 / 76 36 7 0 GREENWOOD 78 59 77 56 / 84 54 12 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ 22/3/7/17 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SPRINGFIELD MO 638 AM CDT TUE OCT 7 2008 ...UPDATE TO AVIATION... .SYNOPSIS... A STRONG UPPER LOW WAS CURRENTLY ACROSS SOUTHEAST NEBRASKA WITH A TRAILING COLD/COOL (AIR MASS) FRONT ACROSS EASTERN KANSAS. RADAR TRENDS MONDAY EVENING AND EARLY THIS MORNING HAVE THE BULK OF THE HEAVIEST RAINFALL AND CONVECTION ACROSS SOUTHERN ARKANSAS. EARLIER THIS EVENING...A BAND OF HEAVY RAINFALL ASSOCIATED WITH ONE OF THE STRONGER COMPLEXES ACROSS EASTERN OKLAHOMA/WESTERN ARKANSAS LED TO RAINFALL AMOUNTS OF ONE HALF TO LOCALLY ONE INCH SOUTH AND SOUTHWEST OF THE SPRINGFIELD AREA. AS OF 1 AM...THE BULK OF THE HEAVIEST RAINFALL HAS SHIFTED SOUTHEAST OF SPRINGFIELD...AND MAINLY AFFECTING AREAS OF WEST PLAINS...ALTON AND EMINENCE. WATER VAPOR AND RUC ANALYSIS STILL SHOWING EMBEDDED SHORT WAVES ACROSS KANSAS AND NORTHERN OKLAHOMA. JLT && .DISCUSSION... AS THE STRONGEST MOISTURE ADVECTION REMAINS SOUTH OF THE REGION...HAVE OPTED TO DECREASE PERCENTAGES TO LIKELY EAST OF SPRINGFIELD...TO SCATTERED WEST OF SPRINGFIELD. HOWEVER...UPPER LEVEL DYNAMICS ASSOCIATED WITH THE UPPER LOW AND WEAK ISENTROPIC LIFT AND AFTERNOON INSTABILITY OF THE COLD POOL...WILL LIKELY CONTRIBUTE TO ADDITIONAL PRECIPITATION LATER TODAY. WILL LIKELY HOLD OFF UNTIL DAWN TO ADJUST THE MAIN PRECIPITATION AREA THIS MORNING...WITH SCATTERED ACTIVITY THIS AFTERNOON. WILL KEEP ISOLATED/SCATTERED SHOWERS ACROSS THE FAR EASTERN FORECAST AREA THIS EVENING AS THE MAIN UPPER TROUGH REMAINS NEAR THE REGION. THERE SHOULD BE A VERY SHARP CUT OFF LATER TONIGHT WITH THE CLOUD COVER DECREASING RAPIDLY FROM WEST TO EAST. FOG POTENTIAL IS LIKELY WEDNESDAY MORNING WITH CLEAR SKIES/LIGHT WINDS AND RESIDUAL MOISTURE NEAR THE SURFACE. DENSE FOG ADVISORY MAYBE CONSIDERED FOR THE NEXT MIDNIGHT SHIFT. THE EXTENDED OUTLOOK REMAINS VERY ACTIVE ACROSS THE ROCKIES AND NORTHERN PLAINS. ALL MODELS INDICATED THAT A VERY DEEP SYNOPTIC SCALE LOW AND LONG WAVE TROUGH DEVELOPING ACROSS THE WESTERN U.S. LATEST GFS HAS THE MAIN CORE AS FAR SOUTH AS THE FOUR CORNERS AREA OF THE SOUTHWESTERN U.S. THIS WILL LED TO A VERY WARM PATTERN ACROSS THE CENTRAL U.S. WITH MAINLY DRY CONDITIONS. ONCE THIS SYSTEM BEGINS TO MOVE EASTWARD...A VERY ACTIVE WEATHER PATTERN WILL EVOLVE ACROSS OUR REGION. JLT && .AVIATION... FOR THE 1200 UTC KSGF/KJLN TAFS...A MIX MVFR AND IFR CEILINGS ARE OCCURRING OVER THE MISSOURI OZARKS EARLY THIS MORNING. A COLD FRONT OVER EASTERN KANSAS WILL MOVE SLOWLY EAST EAST THROUGH THE AREA TODAY. AHEAD OF THE FRONT SOME SHOWERS AND AT LEAST SOME MODEST RISE IN CEILINGS HEIGHTS IS EXPECTED. BEHIND THE FRONT LOWER IFR/MVFR STRATUS IS EXPECTED LATE TODAY AND TONIGHT. DSA && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ mo AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BURLINGTON VT 912 AM EDT TUE OCT 7 2008 .SYNOPSIS... A STRONG AREA OF HIGH PRESSURE WILL MOVE SLOWLY ACROSS THE NORTH COUNTRY THROUGH WEDNESDAY...BRINGING FAIR CONDITIONS TO THE REGION. TONIGHT WILL FEATURE CHILLY TEMPERATURES ONCE AGAIN...ALONG WITH AREAS OF FROST. A FRONTAL SYSTEM WILL MOVE ACROSS THE REGION WEDNESDAY NIGHT THROUGH THURSDAY...BRINGING OUR NEXT CHANCE FOR SHOWERS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... AS OF 905 AM EDT TUESDAY...NEARLY FULL SUNSHINE EXPECTED TODAY AS DEEP-LAYER RIDGE AXIS ACROSS THE ERN GREAT LAKES REGION SHIFTS SLOWLY EWD CRESTING ACROSS THE FORECAST AREA TONIGHT. SOME CIRRUS EVIDENT ON IR IMAGERY NORTH OF THE ST. LAWRENCE RIVER MAY AFFECT ERN VT THIS AFTERNOON. LOW CLOUDS ARE NOT EXPECTED. SFC TEMPERATURES WILL MODERATE TODAY AS 850MB TEMPERATURES HAVE WARMED TO +4 TO +5C BASED ON 13Z RUC ANALYSIS. AFTN HIGH TEMPS JUST A BIT BELOW SEASONAL NORMS WITH HIGHS MAINLY IN THE UPPER 50S TO LOWER 60S. WINDS WILL CONTINUE FROM THE NORTHWEST ON ERN PERIPHERY OF THE HIGH PRESSURE AREA. WITH PBL MIXING...WIND SPEEDS AROUND 10KTS EXPECTED LATE THIS MORNING THRU THE AFTN...WITH GUSTS 15-18 KTS IN LOCATIONS WITH NORTHWEST EXPOSURE BEFORE DIMINISHING LATE IN THE DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/... AS OF 425 AM EDT TUESDAY...WEATHER TONIGHT THRU WEDNESDAY WILL CONTINUE TO BE DOMINATED BY HIGH PRESSURE...WHICH WILL BE ANCHORED OVER THE FORECAST AREA TONIGHT...THEN SLIDE SOUTHEAST OF THE AREA DURING WEDNESDAY. ANOTHER CHILLY NIGHT TONIGHT...WITH MORE FROST/FREEZE CONDITIONS EXPECTED AS TEMPS FALL INTO THE 20S AND LOWER 30S...EVEN SOME TEENS PSBL IN THE SHELTERED VLYS OF THE ADRNDKS. NO HEADLINES ATTM HOWEVER...AS SOME LOCATIONS WILL SEE AN END TO THE GROWING SEASON THIS MORNING. WILL DEFER TO DAYSHIFT TO DECIDE WHICH AREAS WILL STILL REQUIRE NEED FOR ANY HEADLINES. AS HIGH MOVES EAST OF THE AREA WED PM...EXPECT AN INCR IN CLDS OVER WRN ZONES WITH ONSET OF WAA. CLOUDS WILL OVERSPREAD REST OF THE AREA WED NITE...ALONG WITH AN INCREASING CHANCES FOR SHWRS AS WRMFNT AND ASSOCD SHRTWV MOVE INTO THE REGION. BEST CHC FOR SHWRS WILL BE OVER NRN ZONES. CHANCE OF SHWRS CONTINUES THURS MORNING AS WEAK CDFNT MOVES ACRS THE AREA. TEMPS WED/THURS A LITTLE ABOVE NORMAL WITH HIGHS MAINLY IN THE 60S. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... AS OF 425 AM EDT TUESDAY...DRIER AIR FILTERS INTO THE AREA THURS NITE AS HIGH PRESSURE BUILDS EAST FROM THE GRTLKS. THIS HIGH ALONG WITH BUILDING RIDGE ALOFT WILL PROVIDE THE NORTH COUNTRY WITH DRY WX FRIDAY THRU SATURDAY. ANY LOW PRESSURE DISTURBANCE THAT FORMS OVER THE CAROLINAS IS NOW EXPECTED TO REMAIN SUPPPRESSED TO OUR SOUTH. STRONG SHRTWV DROPS SOUTHEAST ACRS ERN CANADA SUNDAY INTO SUNDAY NIGHT. THIS WILL ALLOW FOR BACKDOOR CDFNT TO DROP SOUTH ACRS THE FA BRINGING A CHC OF SHWRS. HIGH PRESSURE THEN BUILDS SOUTH FROM QUEBEC DURING COLUMBUS DAY. && .AVIATION /13Z TUESDAY THROUGH SATURDAY/... THROUGH 12Z WEDNESDAY...LIFR DEVELOPED AT KSLK OVERNIGHT...AND CONTINUES. KMSS DIPPED BELOW 2 SM AROUND 08Z...BUT RECOVERED TO VFR P6SM SKC. KMPV REMAINED FOG/CIG FREE OVERNIGHT. LIFR AT KSLK TO IMPROVE TO VFR P6SM SKC BY 13Z. OTHERWISE VFR CLR ELSEWHERE...WITH NW WIND INCREASING TO 8-10KTS. PUT LIFR FZFG AND CIGS AT KVSF AND KMPV AS RIDGE RIGHT OVERHEAD...AND ANY EFFECTS THE LOW LEVEL WIND JUST ABOVE THE BOUNDARY LAYER SHOULD BE GONE. 12Z WEDNESDAY THROUGH SATURDAY...RIDGE AXIS SHIFTS TO EAST BY 12Z...AND BOUNDARY LAYER WINDS TO TURN SOUTHERLY DURING THE DAY WITH INCREASING LOW LEVEL MOISTURE. VFR TO CONTINUE THROUGH WEDNESDAY NIGHT. A WEAKENING COLD FRONT WILL MOVE THROUGH THE FORECAST AREA THURSDAY WITH CHC FOR MVFR TO VFR SHRA- TO ALL TAF SITES. GIVEN THE LACK OF MOISTURE WITH THIS SYSTEM...CONDITIONS SHOULD REMAIN VFR/MVFR. HIGH PRESSURE AND FAIR WEATHER AND VFR CONDS WILL RETURN BY FRIDAY MORNING. LATEST MODEL GUIDANCE BACKING OFF RAIN POTENTIAL ON SATURDAY WITH HIGH PRESSURE REMAINING OVER THE NORTH COUNTRY. NOTICE TO USERS OF TERMINAL AERODROME FORECASTS (TAF)...BEGINNING AT 0000 UTC ON NOVEMBER 5...2008...THE FORMAT FOR TAFS WILL CHANGE. THE NATIONAL WEATHER SERVICE WILL BEGIN TO ISSUE TAFS USING A VALID DATE AND TIME GROUP IN THE FORECAST. ALL METEOROLOGICAL AGENCIES WORLDWIDE WILL ALSO ISSUE THEIR TAF FORECASTS IN THIS NEW FORMAT. THIS IS BEING DONE TO ACCOMMODATE 30 HOUR TAF FORECASTS THAT WILL BE DONE FOR SELECT MAJOR INTERNATIONAL AIRPORTS WORLDWIDE. THERE WILL BE 32 MAJOR U.S. INTERNATIONAL AIRPORTS FOR WHICH TAFS FORECASTS WILL BE VALID FOR 30 HOURS. THIS FORMAT CHANGE IS BEING MANDATED BY THE INTERNATIONAL CIVIL AVIATION ORGANIZATION (ICAO). THE 6 TAF FORECASTS BEING DONE BY THE NATIONAL WEATHER SERVICE IN BURLINGTON WILL CONTINUE TO BE VALID FOR 24 HOURS. TO SEE EXAMPLES OF THIS NEW FORMAT...PLEASE GO TO THE INTERNET WEB SITE LISTED BELOW. WWW.AVIATIONWEATHER.GOV/NOTICE/TAF30.PHP (ALL LOWER CASE) && .BTV WATCHES/WARNINGS/ADVISORIES... VT...NONE. NY...NONE. && $$ SYNOPSIS...RJS NEAR TERM...BANACOS SHORT TERM...RJS LONG TERM...RJS AVIATION...HANSON ny AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 714 AM CDT TUE OCT 7 2008 .AVIATION.../12Z UPDATE/ VFR CONDS TO PREVAIL BEHIND BACK EDGE OF CLOUD SHIELD WHICH IS MOVING THROUGH EASTERN PORTIONS OF NORTH TEXAS ATTM. WINDS WILL BE MAIN CONCERN TODAY AND SHOULD INCREASE TO 33023G33KT BY LATE MORNING PERSISTING INTO THE AFTERNOON. WINDS WILL DECREASE BY EARLY EVENING. MAY SEE SOME FOG DEVELOP LATE TONIGHT IN AREAS THAT CAN COMPLETELY DECOUPLE...BUT WILL LEAVE P6SM IN ALL SITES WHERE WINDS ARE EXPECTED TO BE SUFFICIENTLY HIGH TO KEEP THINGS MIXED. 91/DUNN && .UPDATE... HAVE INCREASED WIND SPEED FORECAST FOR TODAY...ESPECIALLY ALONG AND WEST OF THE I-35 CORRIDOR. A LOOK AT THE 12Z RAOB ALREADY SHOWS 1000 FT WINDS AT 30 KT...AND RUC FORECASTS TODAY DEPICT 30-35 KT WINDS AT 925 MB. THESE WINDS WILL HAVE NO TROUBLE MIXING DOWN GIVEN STEEP LAPSE RATES. THIS WILL PUT WESTERN/CENTRAL CWA WINDS AT 20 TO 30 MPH WITH GUSTS UP TO 40 MPH...WHICH IS JUST ABOVE WIND ADVISORY CRITERIA. THE ADVISORY IS IN EFFECT FROM 10 AM TO 6 PM. TR.92 && .PREV DISCUSSION... /ISSUED 320 AM CDT TUE OCT 7 2008/ UPPER LEVEL TROUGH AXIS IS NOW PUSHING THROUGH NORTH TEXAS WITH OVERNIGHT CONVECTION BEING SHUNTED EAST AND SOUTHEAST OUT OF THE CWA. WILL HAVE SOME VERY LOW POPS FOR RESIDUAL SHOWERS IN THE EXTREME EASTERN ZONES THIS MORNING. A WEAK COLD FRONT WILL SLIDE THROUGH THE REGION DURING THE NEXT FEW HOURS. MEANWHILE...AN UPPER LEVEL LOW WILL INTENSIFY AT THE BASE OF THE UPPER TROUGH TODAY AND TONIGHT OVER THE LOWER MISSISSIPPI VALLEY WHICH MAY RESULT IN SOME WRAP AROUND LOW CLOUDS OVER THE NORTHEAST/EASTERN ZONES THIS AFTERNOON AND EVENING. OTHERWISE...MUCH OF NORTH TEXAS WILL BE SUNNY TODAY...WITH MODEST DRY/COLD ADVECTION TAKING PLACE BEHIND THE FRONT. DEEP MIXING IS ANTICIPATED TODAY...WHICH SHOULD RESULT IN N/NW WINDS OF 10 TO 20 MPH WITH GUSTS TO 30 MPH. WINDS SHOULD DIMINISH QUICKLY AFTER SUNSET WITH STRONG RADIATIONAL COOLING ALLOWING FOR LOWS IN THE MID 40S NW TO MID 50S SE. VERY NICE WEATHER IS ON TAP FOR WEDNESDAY AND THURSDAY AS LIGHT WINDS AND DRY AIRMASS REMAINS IN PLACE. TEMPERATURES WILL CONTINUE TO BE PLEASANTLY COOL AT NIGHT AND SLIGHTLY ABOVE NORMAL DURING THE DAY. CHANGES ARE EXPECTED BY THE WEEKEND AS SOUTHERLY FLOW ORGANIZES AHEAD OF STRONG UPPER LEVEL TROUGH OVER THE INTER MOUNTAIN WEST. CLOUDS/MOISTURE...BOTH FROM THE GULF IN THE LOW LEVELS AND FROM THE PACIFIC IN THE MID-UPPER LEVELS...WILL STREAM INTO THE REGION SATURDAY AND SUNDAY. MODELS TODAY ARE IN MUCH BETTER AGREEMENT...WITH THE GFS SIDING IN THE ECMWF FORECAST CAMP OF THE LAST FEW DAYS. IT APPEARS THAT UPPER TROUGH WILL BE SLOW TO MOVE OUT INTO THE PLAINS WHICH WILL HOLD THE FRONT UP UNTIL MONDAY OR TUESDAY OF NEXT WEEK. WITH THE SLOWER SOLUTION...HAVE PUSHED BACK THE POPS AND KEPT WARM/MUGGY TEMP FORECAST GOING THROUGH MONDAY. WILL SHOW SOME LOW POPS SATURDAY NIGHT THROUGH TUESDAY...WITH THE BEST CHANCES LIKELY OCCURRING WITH FROPA MONDAY NIGHT. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 79 54 84 58 86 / 0 0 0 0 0 WACO, TX 83 52 84 53 87 / 5 0 0 0 0 PARIS, TX 75 51 79 51 82 / 10 0 0 0 0 DENTON, TX 78 49 82 51 86 / 0 0 0 0 0 MCKINNEY, TX 77 50 81 49 84 / 5 0 0 0 0 DALLAS, TX 79 56 83 58 85 / 5 0 0 0 0 TERRELL, TX 78 54 82 54 85 / 10 0 0 0 0 CORSICANA, TX 82 54 84 54 87 / 10 0 0 0 0 TEMPLE, TX 84 53 86 54 88 / 10 0 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 6 PM CDT THIS AFTERNOON FOR TXZ091>093- 100>104-115>120-129>134-141>145-156>159. && $$ / tx AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE FORT WORTH TX 635 AM CDT TUE OCT 7 2008 .UPDATE... HAVE INCREASED WIND SPEED FORECAST FOR TODAY...ESPECIALLY ALONG AND WEST OF THE I-35 CORRIDOR. A LOOK AT THE 12Z RAOB ALREADY SHOWS 1000 FT WINDS AT 30 KT...AND RUC FORECASTS TODAY DEPICT 30-35 KT WINDS AT 925 MB. THESE WINDS WILL HAVE NO TROUBLE MIXING DOWN GIVEN STEEP LAPSE RATES. THIS WILL PUT WESTERN/CENTRAL CWA WINDS AT 20 TO 30 MPH WITH GUSTS UP TO 40 MPH...WHICH IS JUST ABOVE WIND ADVISORY CRITERIA. THE ADVISORY IS IN EFFECT FROM 10 AM TO 6 PM. TR.92 && .PREV DISCUSSION... /ISSUED 320 AM CDT TUE OCT 7 2008/ UPPER LEVEL TROUGH AXIS IS NOW PUSHING THROUGH NORTH TEXAS WITH OVERNIGHT CONVECTION BEING SHUNTED EAST AND SOUTHEAST OUT OF THE CWA. WILL HAVE SOME VERY LOW POPS FOR RESIDUAL SHOWERS IN THE EXTREME EASTERN ZONES THIS MORNING. A WEAK COLD FRONT WILL SLIDE THROUGH THE REGION DURING THE NEXT FEW HOURS. MEANWHILE...AN UPPER LEVEL LOW WILL INTENSIFY AT THE BASE OF THE UPPER TROUGH TODAY AND TONIGHT OVER THE LOWER MISSISSIPPI VALLEY WHICH MAY RESULT IN SOME WRAP AROUND LOW CLOUDS OVER THE NORTHEAST/EASTERN ZONES THIS AFTERNOON AND EVENING. OTHERWISE...MUCH OF NORTH TEXAS WILL BE SUNNY TODAY...WITH MODEST DRY/COLD ADVECTION TAKING PLACE BEHIND THE FRONT. DEEP MIXING IS ANTICIPATED TODAY...WHICH SHOULD RESULT IN N/NW WINDS OF 10 TO 20 MPH WITH GUSTS TO 30 MPH. WINDS SHOULD DIMINISH QUICKLY AFTER SUNSET WITH STRONG RADIATIONAL COOLING ALLOWING FOR LOWS IN THE MID 40S NW TO MID 50S SE. VERY NICE WEATHER IS ON TAP FOR WEDNESDAY AND THURSDAY AS LIGHT WINDS AND DRY AIRMASS REMAINS IN PLACE. TEMPERATURES WILL CONTINUE TO BE PLEASANTLY COOL AT NIGHT AND SLIGHTLY ABOVE NORMAL DURING THE DAY. CHANGES ARE EXPECTED BY THE WEEKEND AS SOUTHERLY FLOW ORGANIZES AHEAD OF STRONG UPPER LEVEL TROUGH OVER THE INTER MOUNTAIN WEST. CLOUDS/MOISTURE...BOTH FROM THE GULF IN THE LOW LEVELS AND FROM THE PACIFIC IN THE MID-UPPER LEVELS...WILL STREAM INTO THE REGION SATURDAY AND SUNDAY. MODELS TODAY ARE IN MUCH BETTER AGREEMENT...WITH THE GFS SIDING IN THE ECMWF FORECAST CAMP OF THE LAST FEW DAYS. IT APPEARS THAT UPPER TROUGH WILL BE SLOW TO MOVE OUT INTO THE PLAINS WHICH WILL HOLD THE FRONT UP UNTIL MONDAY OR TUESDAY OF NEXT WEEK. WITH THE SLOWER SOLUTION...HAVE PUSHED BACK THE POPS AND KEPT WARM/MUGGY TEMP FORECAST GOING THROUGH MONDAY. WILL SHOW SOME LOW POPS SATURDAY NIGHT THROUGH TUESDAY...WITH THE BEST CHANCES LIKELY OCCURRING WITH FROPA MONDAY NIGHT. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 79 54 84 58 86 / 0 0 0 0 0 WACO, TX 83 52 84 53 87 / 5 0 0 0 0 PARIS, TX 75 51 79 51 82 / 10 0 0 0 0 DENTON, TX 78 49 82 51 86 / 0 0 0 0 0 MCKINNEY, TX 77 50 81 49 84 / 5 0 0 0 0 DALLAS, TX 79 56 83 58 85 / 5 0 0 0 0 TERRELL, TX 78 54 82 54 85 / 10 0 0 0 0 CORSICANA, TX 82 54 84 54 87 / 10 0 0 0 0 TEMPLE, TX 84 53 86 54 88 / 10 0 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY FROM 10 AM THIS MORNING TO 6 PM CDT THIS AFTERNOON FOR TXZ091>093-100>104-115>120-129>134-141>145-156>159. && $$ 91/92 tx AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE SHREVEPORT LA 1148 AM CDT TUE OCT 7 2008 .AVIATION... PRE-FRONTAL SFC TROUGH NOW PUSHING TOWARD RUSKIN/ALEXANDRIA LINE...WHILE CD FNT IS MOVING THRU E TX ATTM. A HUNDRED OR SO MILES BEHIND CD FROPA... SOME MVFR CIGS ARE NOTED BTWN 1.5-2.5 KFT AND WILL GENERALLY FOLLOW A BLEND OF THE RUC40/GFS40 BL MOISTURE FCSTS WHICH MAY CLR A FEW OF THE E TX AIRPORTS OUT AN HR OR TWO SOONER THAN CURRENTLY FCST. AIRMASS WILL SEE DRYING WITH DECENT CAA BEHIND FROPA OVERNIGHT...AS SLY WINDS AHEAD OF SFC TROUGH CURRENTLY SHIFT WLY 8-11 KTS...THEN NWLY 10-15 KTS...WITH A FEW GUSTS IN EXCESS OF 20 KTS PSBL THRU 03Z. W/NW WINDS DIMINISHING BELOW 10 KTS WITH RAPID DECOUPLING WITH INTENSIFYING SFC INVERSION THRU DAYBREAK OR 12Z- 14Z WED...BEFORE MIXING RESULTS IN NW WINDS AROUND 10 KTS TOWARD 18Z WED. && .PREV DISCUSSION... /ISSUED 1106 AM CDT TUE OCT 7 2008/ DISCUSSION... A FEW CHANGES WERE MADE TO THE MORNING FORECAST PACKAGE CONCERNING HIGH TEMPERATURES AND RAIN CHANCES. HIGHS TODAY WILL BE A LITTLE BIT OF A CHALLENGE WITH A COLD FRONT DRAPED ACROSS NORTHEAST TEXAS AND SOUTHEAST OKLAHOMA MAKING IT WAY EASTWARD. TROPICAL AIR REMAINS IN PLACE AHEAD OF THE FRONT...WITH BROKEN CLOUD COVER AND SPOTTY SHOWERS AND THUNDERSTORMS OVER THE EAST. CLOUDS HAVE BEEN KEEPING A LID ON TEMPERATURE INCREASES OVER MUCH OF THE REGION...SO THEREFORE HAVE LOWERED HIGHS AREAWIDE...KEEPING IN MIND THAT TEMPERATURES WILL SPIKE UPWARD WHERE SUNSHINE BREAKS THROUGH THIS AFTERNOON. MORNING RADAR IMAGERY INDICATES SHOWERS AND THUNDERSTORMS MOVING ACROSS NORTH CENTRAL LOUISIANA AND SOUTHERN ARKANSAS...BUT WITH THE FRONT STILL TO THE WEST...AND DEWPOINTS HOVERING IN THE UPPER 60S AHEAD OF THE BOUNDARY...EXPECT ADDITIONAL SHOWERS AND THUNDERSTORMS TO DEVELOP WITH AFTERNOON HEATING...MAINLY OVER THE EASTERN HALF OF THE REGION. LAPSE RATES AND CAPE VALUES WITH BE SUFFICIENT THAT ISOLATED SEVERE THUNDERSTORMS MAY DEVELOP...WITH BOTH LARGE HAIL AND STRONG WINDS AS THREATS. /18/ AVIATION... PREFRONTAL TROUGH RESIDES ACROSS SW AR INTO NE TX WITH THE TRUE FRONT WITH AN INCREASING PRESSURE GRADIENT ACROSS NE TX AND SE OK. CONVECTION THIS MORNING REMAINS CONFINED OUT AHEAD OF THE PREFRONTAL SFC TROUGH ACROSS EAST CENTRAL AND NE LA. DEPENDING ON WHERE THIS CONVECTION IS CLOSER TO THE 18Z PACKAGE...MAY NEED TO MAKE MENTION OF AN HOUR OR TWO TEMPO TSRA AT MLU/ELD TERMINALS. OTHERWISE... CEILINGS WILL REMAIN TRICKY BEHIND THE PREFRONTAL TROUGH WITH MANY TERMINALS ACROSS NE TX WITH IFR CEILINGS. STRATOCUMULUS DECK WILL CONTINUE TO FILL IN BEHIND THE INITIAL BOUNDARY WITH MOST TERMINALS KEEPING IFR/LOW MVFR CEILINGS THROUGHOUT THE DAY AND INTO TONIGHT. CLOUDS SPILLING SOUTHWARD ACROSS NORTH TEXAS BEHIND THE SECONDARY BOUNDARY WILL LIKELY KEEP CLOUDS SOCKED IN OVERNIGHT AS WELL. WILL LIKELY SEE A FEW WIND GUSTS FROM THE NW BEHIND THE SECONDARY BOUNDARY AS WELL AT NE TX TERMINALS THIS AFTERNOON BEFORE WINDS DECOUPLE TONIGHT. /13/ && .PRELIMINARY POINT TEMPS/POPS... SHV MMM MMM MMM MMM MMM / MMM MMM MMM MMM MMM MLU MMM MMM MMM MMM MMM / MMM MMM MMM MMM MMM DEQ MMM MMM MMM MMM MMM / MMM MMM MMM MMM MMM TXK MMM MMM MMM MMM MMM / MMM MMM MMM MMM MMM ELD MMM MMM MMM MMM MMM / MMM MMM MMM MMM MMM TYR MMM MMM MMM MMM MMM / MMM MMM MMM MMM MMM GGG MMM MMM MMM MMM MMM / MMM MMM MMM MMM MMM LFK MMM MMM MMM MMM MMM / MMM MMM MMM MMM MMM && .SHV WATCHES/WARNINGS/ADVISORIES... AR...NONE. LA...NONE. OK...NONE. TX...NONE. && $$ 18/15/05 la AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 409 PM EDT TUE OCT 7 2008 .SYNOPSIS... WV IMAGERY AND RUC ANALYSIS INDICATED A MID/UPPER LEVEL RIDGE FROM FL TO HUDSON BAY AND A TROUGH FROM MANITOBA TO OK/NE TX. A LARGE ARES OF PCPN FROM ERN MN INTO WRN WI WAS SUPPORTED BY 850-500 MB QVECTOR CONV AND 900-700 MB FGEN AHEAD OF THE MID LEVEL TROUGH. AN ADDITIONAL BATCH OF RAIN FROM ERN IA AND NRN IL INTO SRN/CNTRL WI WAS SUPPORTED BY A SHORTWAVE OVER CNTRL IL. AT THE SFC...SOUTHEASTERLY FLOW PREVAILED THROUGH THE CWA BTWN HIGH PRES OVER THE ERN LAKES AND A FRONT/TROUGH EXTENDED FROM ERN MN TO LOW PRES OVER CNTRL MO. && .SHORT TERM (TONIGHT AND WED)... TONIGHT...EXPECT THE AREA OF SHOWERS TO THE WEST TO GRADUALLY SPREAD INTO WEST UPPER MICHIGAN THIS EVENING. AT THE SAME TIME...THE RAIN AREA ASSOCIATED WITH THE IL SHRTWV AND DEVELOPING SFC LOW WILL LIFT NE INTO THE SOUTHERN CWA THIS EVENING AND OVERNIGHT(AFT 03Z) INTO THE EAST HALF. SO WHILE THE HEAVIEST PCPN...IN THE 0.25-0.50 INCH RANGE IS EXPECTED OVER THE WEST AND EASTERN THIRDS...FCST INCLUDES CATEGORICAL POPS OVER THE AREA AS THE COMBINATION OF DECENT MOISTURE TRANSPORT (PWAT VALUES TO 1.00-1.25 INCH) AND MODERATE QG DYNAMICS BRING WIDESPREAD RAINFALL TO THE CWA. WED...AS THE SHRTWV AND MID LEVEL TROUGH LIFT TO THE ENE AND 700-300 MB QVECTOR CONV/SFC/MID LEVEL RIDGING BUILDS IN LINGERING RAIN IS EXPECTED TO DEPART FROM THE EAST HALF BTWN 12Z-15Z WITH ONLY LEFTOVER SLIGHT CHANCE TOWARD KERY BTWN 15Z-18Z. CLEARING SHOULD WORK INTO THE WEST IN THE AFTERNOON AND LATE OVER THE EAST HALF. .LONG TERM (WED NIGHT THROUGH NEXT TUE)... WED NIGHT AND THU...A DRY PERIOD IS EXPECTED WITH THE AREA MOSTLY IN A DRY SLOT. THIS DRY SLOT IS ASSOCIATED WITH THE CURRENT UPPER TROUGH OVER SW CANADA THAT MOVES EASTWARD ACROSS SOUTHERN CANADA TO NEAR JAMES BAY BY 00Z FRI. ALTHOUGH THE PCPN FORECAST IS DRY...THERE ARE A FEW ITEMS OF INTEREST. FIRST LOOKS TO BE A BAND OF MID CLOUDS ASSOCIATED WITH WEAK 850MB THETA-E ADVECTION THAT CROSSES WED NIGHT WEST TO EAST. THIS BAND OF CLOUDS COULD HELP HOLD TEMPERATURES UP...DESPITE 0.25 INCH PRECIPITABLE WATER VALUES ADVECTING IN FROM THE WEST. ANOTHER ITEM TO HOLD TEMPERATURES UP IS THE WINDS. ASSOCIATED WITH THE UPPER TROUGH WILL BE A FAIRLY DEEP SFC LOW (AROUND 995MB). AS THIS LOW MOVES INTO NW ONTARIO LATE WED NIGHT AND HIGH PRESSURE BUILDS SE INTO IOWA...WESTERLY WINDS WILL INCREASE. WINDS ARE EXPECTED TO CONTINUE INCREASING ON THU AS THE LOW MOVES ACROSS NORTHERN ONTARIO AND THE HIGH SHIFTS ACROSS SOUTHERN WI...TIGHTENING THE PRESSURE GRADIENT. IN ADDITION...WITH A DRY AIRMASS MOVING IN WITH PRECIPITABLE WATER LESS THAN 0.25 INCH PROMOTING DAYTIME MIXING...TRANSPORT OF WINDS TO THE SURFACE WILL BE BETTER. IN FACT...GUSTS OF 40 MPH OR SO LOOK LIKELY OVER THE KEWEENAW. FUTURE SHIFTS MAY HAVE TO MONITOR THE NEED FOR A WIND ADVISORY THERE. REGARDING TEMPS...STAYED CLOSER TO MAV GUIDANCE FOR LOWS ON WED NIGHT WHICH ARE WARMER THAN THE MET...WHICH SEEMS BETTER TO GO WITH GIVEN THE CLOUDS AND INCREASING WIND. ON THU...ALTHOUGH 850MB TEMPS ARE A COOLER 2-4C...DEEP MIXING IN THE DRY SLOT IS EXPECTED...POSSIBLY UP TO 750MB. THIS SHOULD ALLOW FOR READINGS IN THE UPPER 50S TO MID 60S...WARMEST SOUTH CENTRAL. THU NIGHT AND FRI...LARGE UPPER TROUGH IS PROGGED TO DEVELOP DURING THIS PERIOD OVER THE WESTERN U.S....CAUSING RIDGING TO DEVELOP DOWNSTREAM OVER THE OHIO VALLEY AND EVENTUALLY NORTH INTO THE WESTERN GREAT LAKES. THIS BUILDING RIDGE SHOULD SHOVE THE UPPER TROUGH OVER JAMES BAY EASTWARD INTO QUEBEC...ALLOWING THE HIGH PRESSURE RIDGE OVER SRN WI AT 00Z FRI TO LIFT NORTH ACROSS UPPER MI FRI MORNING. THIS SFC RIDGE WILL ALLOW WINDS TO DIMINISH...WHICH WOULD BE GOOD FOR RADIATIONAL COOLING. ONLY PROBLEM IS THAT MID-LEVEL FRONTOGENESIS INCREASES THROUGH THE NIGHT ASSOCIATED WITH THE WARM ADVECTION FROM THE BUILDING UPPER RIDGE. THE NAM AND GFS EVEN PRODUCE SOME LIGHT PCPN OUT OF THE FRONTOGENESIS...ESPECIALLY THE NAM. ALTHOUGH THE LOW LEVEL AIRMASS IS DRY INITIALLY... PRECIPITABLE WATER PROGS SUGGEST THAT IT MAY MOISTEN UP FAIRLY QUICK THROUGH THE NIGHT...SO HAVE DECIDED TO INCLUDE SOME SLIGHT CHANCE POPS. THESE LOWER POPS SHIFT OVER WESTERN LAKE SUPERIOR ON FRI AS WARM ADVECTION CONTINUES...WHICH ALLOWS FOR DRY WEATHER OVER UPPER MI ON FRI. SKIES...HOWEVER...WILL STILL BE PARTLY TO MOSTLY CLOUDY. FOLLOWED AGAIN CLOSER TO MAV GUIDANCE FOR THU NIGHT GIVEN THE INCREASING CLOUDS...THOUGH INTERIOR AREAS MAY STILL BE ABLE TO DROP INTO THE MID 30S WITH THE MOSTLY CLEAR EVENING. ON FRI...CLOUDS WILL BE THICKEST OVER THE WEST...KEEPING READINGS IN THE MID 50S THERE. WARMER READINGS EXPECTED IN THE SOUTH CENTRAL WITH MORE SUN AND 850MB TEMPS CLIMBING TO AROUND 6C. FRI NIGHT THROUGH TUE... MODELS...PARTICULARLY THE LAST FEW RUNS OF THE GFS...HAVE COME INTO MUCH BETTER AGREEMENT WITH THE 00Z ECMWF AND PREVIOUS ECMWF RUNS REGARDING THE UPPER LEVEL PATTERN. 00Z GFS ENSEMBLES STILL HAVE SOME SPREAD...ESPECIALLY INTO MON AND TUE... WITH THE EJECTION SPEED OF THE WESTERN U.S. TROUGH. HOWEVER...EVEN THE ENSEMBLES HAVE TRENDED TOWARDS THE ECMWF. THE 00Z UKMET ALSO LOOKS A BIT MORE LIKE THE ECMWF AS WELL...THOUGH THE COLD FRONT IT SHOWS MOVING THROUGH UPPER MI SAT NIGHT IS NOT SUPPORTED BY ANY OF THE OTHER MODELS. THEREFORE...EXTENDED FORECAST WILL RELY ON A BLEND OF THE 00Z ECMWF/06Z GFS...WHICH MAINTAINS MORE FORECAST CONTINUITY. FRI NIGHT AND SAT EXHIBITS A WARM ADVECTION PATTERN WITH BUILDING HEIGHTS OVER THE GREAT LAKES...IN RESPONSE TO THE WESTERN TROUGH CLOSING OFF INTO A LARGE UPPER LOW AND NORTHERN STREAM ENERGY PASSING ACROSS HUDSON BAY. THIS WARM ADVECTION COULD SET OFF SOME SHOWERS...PARTICULARLY OVER WESTERN AND NORTHERN LAKE SUPERIOR WHERE THE BETTER FRONTOGENESIS IS TAKING PLACE. THE 06Z GFS PAINTED SHOWERS OVER UPPER MI AND NRN WI AS WELL...THOUGH SOUNDINGS SUGGEST THIS MIGHT BE SUSPECT. NONETHELESS...DO BELIEVE THE GFS SCENARIO OF SOME SORT OF STRATUS DECK FORMING AS MORE MOISTURE MOVES INTO THE COOLER AIRMASS OVER THE CWA. THIS STRATUS DECK MAY MIX OUT SOME ON SAT...PROBABLY IN DOWNSLOPE AREAS...WHILE SE UPSLOPE LOCATIONS SUCH AS THE CENTRAL U.P. MAY HAVE MORE TROUBLE. FOR SAT NIGHT THROUGH SUN NIGHT...CWA IS MOSTLY UNDER UPPER RIDGING...WITH 500MB HEIGHTS THAT COULD APPROACH AN UNSEASONABLY HIGH 588 DAM. THE GFS AND ECMWF SUGGEST WARM ADVECTION PCPN STILL AFFECTING WESTERN AND NORTHERN LAKE SUPERIOR SAT NIGHT...THEN LIFTING INTO ONTARIO ON SUN. GFS IS THEN DRY THROUGH SUN NIGHT...THOUGH THE ECMWF DEPICTS SOME SHOWERS OVER THE EASTERN U.P. THROUGH LOWER MI SUN AFTN INTO SUN NIGHT. THESE APPARENTLY ARE RELATED TO SOME CONVERGENCE ALONG A BACK DOOR COLD FRONT TRYING TO DROP SOUTH ON THE EAST SIDE OF THE UPPER RIDGE. ALSO...THE ECMWF SHOWS PCPN MOVING INTO THE FAR WESTERN CWA ASSOCIATED WITH THE WESTERN UPPER LOW EJECTING OUT. WILL FOLLOW CLOSER TO THE ECMWF IDEA SINCE IT HAS CONTINUITY. FINALLY FOR MON INTO TUE...WARM ADVECTION/UPPER JET/DPVA FORCED PCPN AHEAD OF THE EJECTING WESTERN TROUGH/UPPER LOW WILL MOVE INTO THE CWA. TIMING WISE...IT APPEARS AT LEAST THE WEST HALF OF UPPER MI WILL BE AFFECTED ON MON...PERHAPS ALL OF UPPER MI MON NIGHT AND EASTERN UPPER MI ON TUE. ADJUSTMENTS STILL LOOK POSSIBLE TO THE PCPN TIMING...WHICH WILL DEPEND ON THE WESTERN TROUGH EJECTION. TEMPERATURES THROUGHOUT THE EXTENDED EXPECTED TO BE ABOVE NORMAL...WITH SOME HUMIDITY POSSIBLY CREEPING IN AS WELL FOR SUN INTO MON. HOW WARM TEMPS GET WILL DEPEND ON THE AMOUNT OF SUNSHINE...WHICH IS TRICKY TO FORECAST GIVEN LOW SUN ANGLE NOT ALLOWING FOR AS MUCH MIXING...AND THE POSSIBILITY FOR LOW CLOUDS GIVEN MOISTURE MOVING IN. 850MB TEMPS OF 10-12C THROUGH AT LEAST MON DEFINITELY SUGGEST THE POTENTIAL FOR WARM DAYS. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... VFR CONDITIONS AT KCMX/KSAW WILL GIVE WAY TO IFR CIGS/VSBY TONIGHT AS A BAND OF SHOWERS OVER WESTERN AND SOUTHERN WISCONSIN MOVES SLOWLY THROUGH UPPER MICHIGAN. ONLY SLOW IMPROVEMENT TO MVFR CONDITIONS IS EXPECTED WED MORNING AS LOW LEVEL MOISTURE PERSISTS OVER THE REGION. && .MARINE (FOR THE 4 PM LAKE SUPERIOR FORECAST ISSUANCE)... A TIGHT PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER THE EASTERN GREAT LAKES AND A TROUGH/FRONT MOVING TOWARD THE AREA FROM EASTERN MN WILL CONTINUE TO PRODUCE STIFF SOUTHEAST WINDS TO 30 KT TONIGHT OVER CNTRL AND EAST LAKE SUPERIOR. GENERALLY LIGHT WEST WINDS BEHIND THE FRONT IN THE 5 TO 15 KT RANGE WILL INCREASE TO 15 TO 25 KT OVER THE WEST AS LOW PRESSURE SIDES FROM CNTRL CANADA TOWARD NW ONTARIO. BREEZY WEST WINDS OF 15 TO 25 KT TO START OFF WED EVENING WILL INCREASE THROUGH WED NIGHT AND THU...DUE TO A TIGHTENING PRESSURE GRADIENT BETWEEN HIGH PRESSURE CROSSING SOUTHERN WI AND LOW PRESSURE CROSSING FROM CENTRAL CANADA INTO NORTHERN ONTARIO. GALE FORCE WINDS OF 35 KT ARE POSSIBLE OVER WEST AND NORTH CENTRAL LAKE SUPERIOR. WINDS SHOULD DIMINISH BELOW 20 KT BY LATE THU NIGHT AND THROUGH EARLY FRI AFTERNOON AS THE HIGH PRESSURE AREA OVER SOUTHERN WI MOVES NORTH ACROSS LAKE SUPERIOR. BY LATE FRI AFTERNOON AND INTO FRI EVENING...A PERIOD OF ENE WINDS OF UP TO 30 KT ARE POSSIBLE OVER WESTERN LAKE SUPERIOR...DUE TO DEEPENING LOW PRESSURE IN THE PLAINS AND THE HIGH PRESSURE AREA STRENGTHENING AS IT LIFTS INTO NE ONTARIO. THESE WINDS SHOULD DIMINISH TO BELOW 20 KT AFTER MIDNIGHT FRI NIGHT...AND STAY THAT WAY UNTIL LATER SUN WHEN THE LOW APPROACHES THE GREAT LAKES. AT THAT TIME...E TO SE WINDS OF 15 TO 25 KT ARE EXPECTED. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR... GALE WATCH FROM THURSDAY MORNING THROUGH THURSDAY EVENING FOR LSZ242>244-263-264. LAKE MICHIGAN...NONE. && $$ SYNOPSIS/SHORT TERM...JLB LONG TERM...AJ AVIATION...JLB MARINE...JLB/AJ mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MARQUETTE MI 135 PM EDT TUE OCT 7 2008 UPDATED FOR 18Z AVIATION DISCUSSION .SYNOPSIS... 09Z WATER VAPOR LOOP AND RUC 500MB HEIGHT ANALYSIS SHOWED AN UPR TROUGH OVER THE NRN/CENTRAL PLAINS WITH RIDGING OVER THE GREAT LAKES. A PLUME OF MOISTURE AND FORCING AHEAD OF THE UPR TROUGH SUPPORTING AN AREA OF PCPN FROM THE SRN PLAINS THROUGH IA AND MN. PRECIPITABLE WATER PLOT INDICATING VALUES OF AROUND 1.3 INCHES ALONG THE AXIS OF SHOWER ACTIVITY. && .DISCUSSION... TODAY...MODELS SEEM TO BE TRENDING SLOWER YET WITH ADVANCE OF UPR TROUGH APPROACHING FROM THE NRN PLAINS. THIS IS LIKELY DUE TO THE PROMINENT RIDGING IN PLACE OVER THE WRN GREAT LAKES. THE RIDGE IS FCST TO GRADUALLY MOVE EAST TODAY WITH THE ADVANCE OF THE UPR TROUGH ALLOWING FOR THE SFC TROUGH TO MOVE INTO THE FAR WRN PORTION OF THE CWA. GIVEN THE HIGH PCPN WATER VALUES OF OVER AN INCH MOVING IN ALONG/AHEAD OF THE SFC TROUGH...DECIDED TO KEEP LIKELY POPS IN FOR THE FAR WEST THIS AFTERNOON BUT TRIMMED BACK POPS TO SLIGHT CHC OVER WRN MQT...DICKINSON AND MNM COUNTIES LATE. NOT SURE HOW WELL WE WILL MIX TODAY GIVEN THICKENING OF HIGH CLOUDS FROM THE WEST AND PREVAILING SE FLOW...BUT DECIDED TO FAVOR SLIGHTLY WARMER MET GUIDANCE WHICH IS ALSO IN LINE WITH GOING FCST OF 60-65F. SNDGS INDICATE EVEN IF WE MIX TO JUST OVER 900MB...WE SHOULD BE ABLE TO REACH INTO THE LOWER 60S TO MID 60S. WARMEST READINGS CAN BE EXPECTED IN DOWNSLOPE SE FLOW AREAS... WITH COOLEST READINGS DOWNWIND OF LAKE MICHIGAN. TONIGHT...THE MID LEVEL TROUGH AND SFC TROUGH COME MORE INTO PHASE AS THEY MOVE THROUGH THE REGION TONIGHT. DPVA AHEAD OF THE UPR TROUGH AND A BROAD AREA OF 300-305K ISENTROPIC LIFT WILL COMBINE WITH STRONG MOISTURE INFLOW (PWAT VALUES OF 1.00-1.25 INCHES) TO SUPPORT DECENT COVERAGE OF RAIN. KEPT LIKELY POPS OVER MUCH OF THE FCST AREA. WED INTO THU...ANY LEFTOVER RAIN IS EXPECTED TO DEPART THE EAST HALF OF THE CWA WED MORNING. MODELS THEN INDICATE A MORE ZONAL FLOW PATTERN WITH A MID LEVEL LOW AND SFC TROUGH MOVING THROUGH NRN MANITOBA INTO NW ONTARIO AND A DRY WRLY FLOW OVER THE UPR GREAT LAKES. && .AVIATION (FOR THE 18Z TAF ISSUANCE)... VFR CONDITIONS AT KCMX/KSAW WILL GIVE WAY TO IFR CIGS/VSBY TONIGHT AS A BAND OF SHOWERS OVER WESTERN AND SOUTHERN WISCONSIN MOVES SLOWLY THROUGH UPPER MICHIGAN. ONLY SLOW IMPROVEMENT TO MVFR CONDITIONS IS EXPECTED WED MORNING AS LOW LEVEL MOISTURE PERSISTS OVER THE REGION. && .MARINE (FOR THE 4 AM LAKE SUPERIOR FORECAST ISSUANCE)... A TIGHT PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER EASTERN ONTARIO AND A FRONTAL SYSTEM OVER WESTERN MINNESOTA ARE CREATING NBREEZY SOUTHEAST WINDS WHICH WILL CONTINUE ON LAKE SUPERIOR TODAY... ESPECIALLY ON THE EAST HALF WHERE WINDS GUST SPEEDS OF UP TO 30 KT ARE POSSIBLE. AS THE FRONT MOVES INTO FAR WESTERN LAKE SUPERIOR LATE THIS AFTERNOON AND CROSS THE REST OF THE LAKE TONIGHT INTO WEDNESDAY MORNING...WINDS SHOULD FALL BELOW 20 KT AND GRADUALLY SHIFT TO THE SOUTHWEST. DEEPENING LOW PRESSURE SYSTEM WILL CROSS CENTRAL CANADA TO HUDSON BAY WEDNESDAY THROUGH THURSDAY AS HIGH PRESSURE CROSSES THE SOUTHERN GREAT LAKES CAUSING AN INCREASING WEST WIND OVER LAKE SUPERIOR...POSSIBLY REACHING UP TO 30 KNOTS WEDNESDAY NIGHT AND THURSDAY ACROSS THE NORTHERN PORTION OF THE LAKE. THE HIGH PRESSURE AREA OVER THE SOUTHERN GREAT LAKES SHOULD EXPAND UP INTO THE LAKE SUPERIOR ON FRIDAY BRINGING WINDS DOWN BELOW 20 KT. AS THE FRONTAL BOUNDARY SET UP OVER THE UPPER GREAT LAKES FRIDAY NIGHT AND SATURDAY SOUTHEAST WINDS UP TO 25 KT MAY AFFECT LAKE SUPERIOR DURING THIS PERIOD. && .MQT WATCHES/WARNINGS/ADVISORIES... UPPER MICHIGAN...NONE. LAKE SUPERIOR...NONE LAKE MICHIGAN...NONE. && $$ SYNOPSIS/DICUSSION...VOSS AVIATION...JLB MARINE...DLG mi AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSON MS 315 PM CDT TUE OCT 7 2008 .SHORT TERM...TONIGHT THROUGH THURSDAY...WATER VAPOR IMAGERY/RUC ANALYSIS SHOWS A POTENT SHORTWAVE TROUGH OVER OKLAHOMA THAT IS PROGGED TO MOVE EAST SOUTHEAST AND FORM A CLOSED LOW OVER NORTHEAST MISSISSIPPI WEDNESDAY. THIS CLOSED LOW IS EXPECTED TO CONTINUE SOUTHEAST ACROSS GEORGIA THURSDAY. THE DEVELOPING CLOSED LOW WAS HELPING DRIVE A COLD FRONT THIS AFTERNOON TOWARD OUR CWFA. LATEST SURFACE ANALYSIS PLACED THE COLD FRONT OVER WESTERN ARKANSAS DROPPING SOUTHWEST ACROSS NORTHWEST LOUISIANA. A BAND OF SHOWERS AND THUNDERSTORMS FORMED AHEAD OF THE FRONT OVER CENTRAL LOUISIANA EARLIER THIS AFTERNOON AND HAS SINCE OUTRUN THE COLD FRONT AND HAS MOVED THE ACTIVITY OVER INTO MISSISSIPPI. AHEAD OF THE MAIN CONVECTION THERE WAS A WARM MOIST AIRMASS. SURFACE DEW POINTS WERE IN THE LOWER 70S AND TEMPERATURES WERE IN THE LOWER 80S. RAIN COOLED AIR HAS KNOCKED TEMPERATURES DOWN INTO THE 70S OVER OUR PARISHES AND ARKANSAS COUNTIES. THIS WILL LIMIT POTENTIAL FOR STRONG THUNDERSTORM DEVELOPMENT IN OUR WEST LATE THIS AFTERNOON AND EVENING BEFORE THE FRONT MOVES IN. WL CONTINUE MENTION OF THE POSSIBILITY FOR STRONG TO SEVERE STORMS OVER OUR MISSISSIPPI COUNTIES THIS EVENING. THE COLD FRONT IS EXPECTED TO BE JUST WEST OF THE MISSISSIPPI RIVER AT 00Z AND BE NEAR INTERSTATE 55 BY MIDNIGHT. THE COLD FRONT SHOULD CLEAR MISSISSIPPI BY SUNRISE WEDNESDAY. ALTHOUGH THE BULK OF THE SIGNIFICANT PRECIPITATION WILL BE OVER BY WEDNESDAY MORNING...MOISTURE ASSOCIATED WITH THE CLOSED UPPER LOW THAT WILL MOVE ACROSS NORTHERN MISSISSIPPI WILL RESULT IN PATCHY DRIZZLE IN THE NORTH INTO THE AFTERNOON. CAA IN THE WAKE OF THE FRONT AND THE PROXIMITY OF THE CLOSED LOW WILL RESULT IN A COOLER DAY WEDNESDAY. MAV GUIDANCE TEMPERATURES HAVE COME IN A LITTLE TOO COOL. WL LEAN TOWARD 00Z MAV TEMPS WEDNESDAY WITH HIGHS RANGING FROM THE MID 70S NORTH TO THE UPPER 70S SOUTH. THE CLOSED LOW WILL SHIFT EAST THURSDAY AND RIDGING SURFACE AND ALOFT WILL INCREASE OVER OUR REGION. THIS WILL LEAD TO WARMER AFTERNOON HIGHS BACK ABOVE NORMAL THURSDAY. THE DRY AIRMASS ALONG WITH MOSTLY CLEAR SKIES WILL LEAD TO A COUPLE OF COOL NIGHTS THOUGH. OVERNIGHT LOWS WILL BE BACK INTO THE 50S WEDNESDAY AND THURSDAY NIGHTS. /22/ .LONG TERM...FRIDAY THROUGH TUESDAY...STUCK WITH GUIDANCE AGAIN. THE GFS CONTINUES TO DRY THE AREA OUT...HOPEFULLY THE FORECAST WILL NOT FLIP FLOP. POP VALUES DROPPED FROM 60 PERCENT TO 10 PERCENT FOR THE NORTHWEST PORTIONS OF THE CWA FOR THE UPCOMING WEEKEND. CONSIDERED USING A BLEND AND MAINTAINING LOW CHANCE VALUES JUST IN CASE THE SYSTEM SPEEDS UP. HOWEVER...THE EUROPEAN KEEPS THE AREA DRY AFTER WEDNESDAY. IT HAS BEEN CONSISTENTLY DRY FOR THE PAST FEW RUNS. TOOK RAIN OUT OF THE FORECAST FOR THE REMAINDER OF THE PERIOD. USED A BLEND OF GUIDANCE AND CLIMATOLOGY FOR TEMPS. RAISED HIGHS AND LOWS NEARLY EVERYDAY. A SURFACE HIGH WILL PASS THROUGH THE REGION FRIDAY. BY SATURDAY...AN UPPER LEVEL RIDGE WILL BUILD OVER THE EAST/SOUTHEAST STATES AND HELP KEEP MOISTURE AND RAIN TO THE WEST. THE RIDGE SEEMS TO HOLD THROUGH EARLY NEXT WEEK. RETURN FLOW BY THE WEEKEND WILL WARM THINGS UP...HIGHS MAY APPROACH 90 SUNDAY. BEYOND THE FORECAST PERIOD...THE MODELS NOW SUGGEST THE NEXT COLD FRONT WILL MOVE INTO THE AREA AROUND WEDNESDAY. GUIDANCE SHOWED SOME VERY SMALL RAIN CHANCES...BEING DAY 6 AND 7 OPTED TO KEEP THE AREA DRY. WILL LEAVE THE HWO CLEAR FOR THE EXTENDED. /07/ && .AVIATION...FOR THIS AFTERNOON VFR/MVFR CEILINGS(AROUND 2500 FT) WERE NOTED ACROSS THE REGION AHEAD OF AN APPROACHING COLD FRONT. SOME BRIEF SMALL BREAKS IN CLOUD COVER WERE ALSO NOTED. OCCASIONAL SHOWERS AND THUNDERSTORMS WILL CONTINUE WITH PERIODS OF FREQUENT LIGHTNING AND HEAVY RAINFALL. ISOLATED EPISODES OF DAMAGING THUNDERSTORM WIND GUSTS AND LARGE HAIL WILL BE POSSIBLE IN STRONGER STORMS. EXPECT THE STRONGEST STORMS TO AFFECT KGLH...KGWO...KJAN FOR THIS AFTERNOON...THEN AFFECT NEAR KJAN...KGTR...KMEI AND KHBG SITES FOR TONIGHT. PUT IN WIND GUSTS OF 35G45KT AT TAF SITES WITH THE STRONGER STORMS. EXPECT WIDESPREAD MVFR CEILINGS FOR THE TAF PERIOD ACROSS THE WEST AND WIDESPREAD IFR CEILINGS ACROSS THE EAST HALF. EXPECT THE IFR CEILINGS TO HOLD THROUGH WEDNESDAY MORNING./17/ && .PRELIMINARY POINT TEMPS/POPS... JACKSON 59 76 54 80 / 73 5 0 0 MERIDIAN 61 76 54 81 / 96 22 0 0 VICKSBURG 57 77 52 81 / 51 2 0 0 HATTIESBURG 64 78 53 81 / 82 11 0 0 NATCHEZ 58 77 51 80 / 49 2 0 0 GREENVILLE 59 75 53 83 / 48 4 0 0 GREENWOOD 59 74 53 81 / 69 7 1 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...NONE. LA...NONE. AR...NONE. && $$ SHORT TERM:22 LONG TERM: 07 AVIATION: 17 ms AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 143 PM CDT TUE OCT 7 2008 .UPDATE... UPDATED FORECAST TO REFLECT LOW CLOUDS ERODING MORE QUICKLY FROM THE WEST THAN EXPECTED. SUBSIDENCE AND DRYING ON THE BACKSIDE OF THE UPPER TROUGH HAS BEEN SUFFICIENTLY STRONG TO PREVENT ANY WESTWARD EXPANSION OF THE SCU FIELD DUE TO DAYTIME HEATING. WE ALSO HAVE NUDGED HIGH TEMPS UP A BIT IN A FEW LOCATIONS. && .PREV DISCUSSION... /ISSUED 1135 AM CDT TUE OCT 7 2008/ UPDATE... THE CURRENT FORECAST IS HOLDING UP WELL FOR TODAY. THE CLEARING LINE WITH THE LOW CLOUDS HAS SLOWLY SHIFTED TO THE EAST OF INTERSTATE 35 DURING THE MORNING. THIS GENERAL TREND SHOULD PERSIST THROUGH THE AFTERNOON AS RUC INDICATES THAT THE AIRMASS WILL CONTINUE TO DRY OUT. GUSTY NORTHWEST WINDS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA LEVELS ALTHOUGH ONE OR TWO SPOTS COULD OCCASIONALLY BRUSH IT. SPEEDS SHOULD DIMINISH QUICKLY THIS EVENING AS DECOUPLING OCCURS. PREV DISCUSSION... /ISSUED 405 AM CDT TUE OCT 7 2008/ DISCUSSION...SATELLITE AND RADAR TRENDS SHOWED THE MID AND UPPER TROUGH AXIS PROGRESSING INTO EASTERN OKLAHOMA...REPLACED BY DRIER DOWNSLOPE WINDS AND SINKING AIR. IT WILL BE NOTICEABLY COOLER THIS MORNING...WITH GUSTY NORTH WINDS. THE GREATEST COMBINATION OF COLD ADVECTION AND DIABATIC HEATING WILL OCCUR FROM SOUTHWEST OKLAHOMA INTO WESTERN NORTH TEXAS...AND THIS SHOULD MAKE FOR A WINDY DAY WITH SOME GUSTS AROUND 40 MPH. OVERALL THOUGH...THE SUSTAINED WIND LOOKS TO REMAIN BELOW ADVISORY CRITERIA. TEMPERATURES WILL REBOUND TO THE 70S OVER MUCH OF THE REGION THIS AFTERNOON...BUT CLOUDY AND COOLER CONDITIONS MAY HOLD ON A WHILE LONGER TO THE EAST OF INTERSTATE 35...WHERE MODELS DEPICT A LOW LEVEL CLOUD LAYER TRAPPED BENEATH A STRENGTHENING MID LEVEL INVERSION. CLOUDS WILL MOVE OUT BY EVENING...AND A SURFACE RIDGE WILL RELAX THE WINDS. THIS SHOULD RESULT IN A CHILLY NIGHT...AND WE GAVE SOME THOUGHT TO THE POSSIBILITY OF TEMPERATURES FALLING INTO THE 30S UP NORTH. WE ARE APPROACHING THE FROST SEASON...BUT IN THIS CASE IT APPEARS THAT WARM ADVECTION ALOFT COUPLED WITH NON-ZERO SURFACE WINDS AND DEWPOINTS IN THE 40S SHOULD PREVENT TEMPERATURES FROM BOTTOMING OUT. BY WEDNESDAY AFTERNOON...RETURN FLOW AND A WARMING TREND DEVELOP IN ADVANCE OF THE NEXT TROUGH. IT MAKES SENSE THAT LARGE SCALE TROUGHING WILL OCCUR TO EITHER SIDE OF A MEDIUM WAVELENGTH SUBTROPICAL RIDGE CURRENTLY RESIDING OFFSHORE OF SOUTHERN CALIFORNIA. THUS...THE ECMWF SOLUTION OF RECENT DAYS HAD BEEN PREFERRED...AND THIS MORNING THE GFS DROPPED RIGHT IN LINE WITH THAT SOLUTION. THE 00Z GFS WAS THE MODEL OF CHOICE FOR THE EXTENDED...AND THIS MADE TEMPERATURE INITIALIZATION FAIRLY EASY. THE MEX POPS...HOWEVER...DID NOT RESPOND TO WHAT LOOKS LIKE A VERY GOOD CHANCE FOR RAIN SUNDAY NIGHT THROUGH MONDAY NIGHT. THIS TIMING IS SUPPORTED BY BOTH MODELS...AND THE RAIN SHOULD BE WIDESPREAD...AS MODERATELY STRONG MID LEVEL WIND FIELDS DRAW MODIFIED GULF AIR UP AND OVER A SLOWLY SAGGING FRONT. POPS FOR THOSE PERIODS WERE INCREASED OVER MEX GUIDANCE. AVIATION...INTERMITTENT IFR CEILINGS...BKN015...DEVELOPING THIS MORNING FROM PNC TO OKC AND OUN. EXPECT VFR CONDITIONS TO RESUME UNINTERRUPTED AFTER 15-17Z. ALSO AFTER SUNRISE...SURFACE WINDS WILL GUST CLOSE TO 30 KNOTS AT MOST SITES...PARTICULARLY CSM...HBR...LAW .SPS. WINDS WILL DIMINISH AFTER 22Z. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 72 50 77 51 / 0 0 0 0 HOBART OK 76 49 81 55 / 0 0 0 0 WICHITA FALLS TX 78 52 81 55 / 0 0 0 0 GAGE OK 75 43 79 51 / 0 0 0 0 PONCA CITY OK 69 47 77 51 / 10 0 0 0 DURANT OK 72 51 77 52 / 10 0 0 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 32/30 ok AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NORMAN OK 1135 AM CDT TUE OCT 7 2008 .UPDATE... THE CURRENT FORECAST IS HOLDING UP WELL FOR TODAY. THE CLEARING LINE WITH THE LOW CLOUDS HAS SLOWLY SHIFTED TO THE EAST OF INTERSTATE 35 DURING THE MORNING. THIS GENERAL TREND SHOULD PERSIST THROUGH THE AFTERNOON AS RUC INDICATES THAT THE AIRMASS WILL CONTINUE TO DRY OUT. GUSTY NORTHWEST WINDS ARE EXPECTED TO REMAIN BELOW ADVISORY CRITERIA LEVELS ALTHOUGH ONE OR TWO SPOTS COULD OCCASIONALLY BRUSH IT. SPEEDS SHOULD DIMINISH QUICKLY THIS EVENING AS DECOUPLING OCCURS. && .PREV DISCUSSION... /ISSUED 405 AM CDT TUE OCT 7 2008/ DISCUSSION...SATELLITE AND RADAR TRENDS SHOWED THE MID AND UPPER TROUGH AXIS PROGRESSING INTO EASTERN OKLAHOMA...REPLACED BY DRIER DOWNSLOPE WINDS AND SINKING AIR. IT WILL BE NOTICEABLY COOLER THIS MORNING...WITH GUSTY NORTH WINDS. THE GREATEST COMBINATION OF COLD ADVECTION AND DIABATIC HEATING WILL OCCUR FROM SOUTHWEST OKLAHOMA INTO WESTERN NORTH TEXAS...AND THIS SHOULD MAKE FOR A WINDY DAY WITH SOME GUSTS AROUND 40 MPH. OVERALL THOUGH...THE SUSTAINED WIND LOOKS TO REMAIN BELOW ADVISORY CRITERIA. TEMPERATURES WILL REBOUND TO THE 70S OVER MUCH OF THE REGION THIS AFTERNOON...BUT CLOUDY AND COOLER CONDITIONS MAY HOLD ON A WHILE LONGER TO THE EAST OF INTERSTATE 35...WHERE MODELS DEPICT A LOW LEVEL CLOUD LAYER TRAPPED BENEATH A STRENGTHENING MID LEVEL INVERSION. CLOUDS WILL MOVE OUT BY EVENING...AND A SURFACE RIDGE WILL RELAX THE WINDS. THIS SHOULD RESULT IN A CHILLY NIGHT...AND WE GAVE SOME THOUGHT TO THE POSSIBILITY OF TEMPERATURES FALLING INTO THE 30S UP NORTH. WE ARE APPROACHING THE FROST SEASON...BUT IN THIS CASE IT APPEARS THAT WARM ADVECTION ALOFT COUPLED WITH NON-ZERO SURFACE WINDS AND DEWPOINTS IN THE 40S SHOULD PREVENT TEMPERATURES FROM BOTTOMING OUT. BY WEDNESDAY AFTERNOON...RETURN FLOW AND A WARMING TREND DEVELOP IN ADVANCE OF THE NEXT TROUGH. IT MAKES SENSE THAT LARGE SCALE TROUGHING WILL OCCUR TO EITHER SIDE OF A MEDIUM WAVELENGTH SUBTROPICAL RIDGE CURRENTLY RESIDING OFFSHORE OF SOUTHERN CALIFORNIA. THUS...THE ECMWF SOLUTION OF RECENT DAYS HAD BEEN PREFERRED...AND THIS MORNING THE GFS DROPPED RIGHT IN LINE WITH THAT SOLUTION. THE 00Z GFS WAS THE MODEL OF CHOICE FOR THE EXTENDED...AND THIS MADE TEMPERATURE INITIALIZATION FAIRLY EASY. THE MEX POPS...HOWEVER...DID NOT RESPOND TO WHAT LOOKS LIKE A VERY GOOD CHANCE FOR RAIN SUNDAY NIGHT THROUGH MONDAY NIGHT. THIS TIMING IS SUPPORTED BY BOTH MODELS...AND THE RAIN SHOULD BE WIDESPREAD...AS MODERATELY STRONG MID LEVEL WIND FIELDS DRAW MODIFIED GULF AIR UP AND OVER A SLOWLY SAGGING FRONT. POPS FOR THOSE PERIODS WERE INCREASED OVER MEX GUIDANCE. AVIATION...INTERMITTENT IFR CEILINGS...BKN015...DEVELOPING THIS MORNING FROM PNC TO OKC AND OUN. EXPECT VFR CONDITIONS TO RESUME UNINTERRUPTED AFTER 15-17Z. ALSO AFTER SUNRISE...SURFACE WINDS WILL GUST CLOSE TO 30 KNOTS AT MOST SITES...PARTICULARLY CSM...HBR...LAW ..SPS. WINDS WILL DIMINISH AFTER 22Z. && .PRELIMINARY POINT TEMPS/POPS... OKLAHOMA CITY OK 70 50 77 51 / 0 0 0 0 HOBART OK 76 49 81 55 / 0 0 0 0 WICHITA FALLS TX 76 52 81 55 / 0 0 0 0 GAGE OK 75 43 79 51 / 0 0 0 0 PONCA CITY OK 69 47 77 51 / 10 0 0 0 DURANT OK 72 51 77 52 / 10 0 0 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...NONE. TX...NONE. && $$ 32/30 ok AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE FORT WORTH TX 1150 AM CDT TUE OCT 7 2008 .AVIATION... /18Z TAFS/ THE ONLY CONCERN FOR THE NEXT 24 HOURS WILL BE GUSTY WINDS THIS AFTERNOON AND EARLY EVENING. A NORTHWESTERLY LOW LEVEL JET OFF THE SURFACE WILL KEEP WINDS AROUND 20 KTS WITH GUSTS UP TO 30 KTS. WINDS WILL BEGIN TO SUBSIDE AROUND SUNSET AND DIMINISH TO AROUND 5 KNOTS BEFORE DAYBREAK AS A SURFACE HIGH PRESSURE MOVES INTO NORTH TEXAS. WINDS WILL BACK TO THE WEST AROUND DAY BREAK AS THE CENTER OF THE HIGH SHIFTS TO THE SOUTH. 85/NH && .UPDATE... HAVE INCREASED WIND SPEED FORECAST FOR TODAY...ESPECIALLY ALONG AND WEST OF THE I-35 CORRIDOR. A LOOK AT THE 12Z RAOB ALREADY SHOWS 1000 FT WINDS AT 30 KT...AND RUC FORECASTS TODAY DEPICT 30-35 KT WINDS AT 925 MB. THESE WINDS WILL HAVE NO TROUBLE MIXING DOWN GIVEN STEEP LAPSE RATES. THIS WILL PUT WESTERN/CENTRAL CWA WINDS AT 20 TO 30 MPH WITH GUSTS UP TO 40 MPH...WHICH IS JUST ABOVE WIND ADVISORY CRITERIA. THE ADVISORY IS IN EFFECT FROM 10 AM TO 6 PM. TR.92 && .PREV DISCUSSION... /ISSUED 320 AM CDT TUE OCT 7 2008/ UPPER LEVEL TROUGH AXIS IS NOW PUSHING THROUGH NORTH TEXAS WITH OVERNIGHT CONVECTION BEING SHUNTED EAST AND SOUTHEAST OUT OF THE CWA. WILL HAVE SOME VERY LOW POPS FOR RESIDUAL SHOWERS IN THE EXTREME EASTERN ZONES THIS MORNING. A WEAK COLD FRONT WILL SLIDE THROUGH THE REGION DURING THE NEXT FEW HOURS. MEANWHILE...AN UPPER LEVEL LOW WILL INTENSIFY AT THE BASE OF THE UPPER TROUGH TODAY AND TONIGHT OVER THE LOWER MISSISSIPPI VALLEY WHICH MAY RESULT IN SOME WRAP AROUND LOW CLOUDS OVER THE NORTHEAST/EASTERN ZONES THIS AFTERNOON AND EVENING. OTHERWISE...MUCH OF NORTH TEXAS WILL BE SUNNY TODAY...WITH MODEST DRY/COLD ADVECTION TAKING PLACE BEHIND THE FRONT. DEEP MIXING IS ANTICIPATED TODAY...WHICH SHOULD RESULT IN N/NW WINDS OF 10 TO 20 MPH WITH GUSTS TO 30 MPH. WINDS SHOULD DIMINISH QUICKLY AFTER SUNSET WITH STRONG RADIATIONAL COOLING ALLOWING FOR LOWS IN THE MID 40S NW TO MID 50S SE. VERY NICE WEATHER IS ON TAP FOR WEDNESDAY AND THURSDAY AS LIGHT WINDS AND DRY AIRMASS REMAINS IN PLACE. TEMPERATURES WILL CONTINUE TO BE PLEASANTLY COOL AT NIGHT AND SLIGHTLY ABOVE NORMAL DURING THE DAY. CHANGES ARE EXPECTED BY THE WEEKEND AS SOUTHERLY FLOW ORGANIZES AHEAD OF STRONG UPPER LEVEL TROUGH OVER THE INTER MOUNTAIN WEST. CLOUDS/MOISTURE...BOTH FROM THE GULF IN THE LOW LEVELS AND FROM THE PACIFIC IN THE MID-UPPER LEVELS...WILL STREAM INTO THE REGION SATURDAY AND SUNDAY. MODELS TODAY ARE IN MUCH BETTER AGREEMENT...WITH THE GFS SIDING IN THE ECMWF FORECAST CAMP OF THE LAST FEW DAYS. IT APPEARS THAT UPPER TROUGH WILL BE SLOW TO MOVE OUT INTO THE PLAINS WHICH WILL HOLD THE FRONT UP UNTIL MONDAY OR TUESDAY OF NEXT WEEK. WITH THE SLOWER SOLUTION...HAVE PUSHED BACK THE POPS AND KEPT WARM/MUGGY TEMP FORECAST GOING THROUGH MONDAY. WILL SHOW SOME LOW POPS SATURDAY NIGHT THROUGH TUESDAY...WITH THE BEST CHANCES LIKELY OCCURRING WITH FROPA MONDAY NIGHT. TR.92 && .PRELIMINARY POINT TEMPS/POPS... DALLAS-FT. WORTH, TX 79 54 84 58 86 / 0 0 0 0 0 WACO, TX 83 52 84 53 87 / 5 0 0 0 0 PARIS, TX 75 51 79 51 82 / 10 0 0 0 0 DENTON, TX 78 49 82 51 86 / 0 0 0 0 0 MCKINNEY, TX 77 50 81 49 84 / 5 0 0 0 0 DALLAS, TX 79 56 83 58 85 / 5 0 0 0 0 TERRELL, TX 78 54 82 54 85 / 10 0 0 0 0 CORSICANA, TX 82 54 84 54 87 / 10 0 0 0 0 TEMPLE, TX 84 53 86 54 88 / 10 0 0 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... WIND ADVISORY UNTIL 6 PM CDT THIS AFTERNOON FOR TXZ091>093- 100>104-115>120-129>134-141>145-156>159. && $$ 85/84 tx