####018003854#### FXUS62 KTAE 161412 AFDTAE AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TALLAHASSEE FL 912 AM EST MON FEB 16 2009 .UPDATE...RECENTLY ANIMATED WATER VAPOR LOOP SHOWED RISING UPPER HEIGHTS ACROSS THE REGION WITH A BROAD RIDGE AXIS EXTENDING NORTH ACROSS THE PLAINS AND A SHORTWAVE TROUGH CENTERED OVER THE EAST COAST. MID TO UPPER-LEVEL MOISTURE CONTINUES TO STREAM WEST TO EAST ACROSS THE LOCAL AREA BETWEEN THESE TWO FEATURES. EARLY MORNING VISIBLE IMAGERY DID INDICATE SOME UPPER-LEVEL CLOUDS PUSHING INTO OUR SOUTHEAST ALABAMA AND EASTERN FLORIDA PANHANDLE COUNTIES. THE MORNING SURFACE ANALYSIS SHOWED A LARGE HIGH PRESSURE CENTERED NORTH-NORTHWEST OF THE AREA WITH A RIDGE AXIS EXTENDING SOUTH ACROSS THE LOWER MS VALLEY. AS A RESULT...EXPECT NORTHERLY WINDS WITH A FEW MODERATE GUSTS TO CONTINUE THROUGH THE DAY TODAY. DEWPOINTS WILL STEADILY DROP THROUGH THE DAY AND SHOULD REACH THE MID TO UPPER 20S AS THE COOLER AND DRIER AIR CONTINUES TO FILL IN THROUGH THE AFTERNOON HOURS. TEMPERATURES WILL CLIMB INTO THE LOWER 60S ACROSS SOUTHEAST ALABAMA AND SOUTH GEORGIA AND UP TO THE MID TO UPPER 60S ACROSS NORTHWEST FLORIDA THIS AFTERNOON. ONLY A FEW MINOR TWEAKS WERE MADE TO THE GRIDS THIS MORNING AND NO PRODUCT UPDATES ARE EXPECTED AT THIS TIME. && .AVIATION...EXPECT VFR CONDITIONS AT ALL LOCATIONS FOR THE TAF PERIOD WITH JUST SOME CIRRUS MOVING IN FROM THE WEST...ALONG WITH GUSTY NORTHERLY SFC WINDS OF 10 TO 15 KTS DURING THE DAYLIGHT HOURS TODAY. && .FIRE WEATHER...DRY AIR ARRIVING FROM THE NORTHWEST WILL COMBINE WITH AFTERNOON TEMPERATURES IN THE 60S TO PRODUCE WIDESPREAD LOW RH VALUES. RED FLAG WARNINGS CONTINUE FOR ALL OF THE EASTERN FLORIDA PANHANDLE AND FLORIDA BIG BEND...AND HAVE NOW BEEN EXPANDED TO INCLUDE ALL OF SOUTHEAST ALABAMA AND A LARGE PORTION OF SW GEORGIA. LINGERING DRY AIR THROUGH TUESDAY AFTERNOON IS ANTICIPATED TO ONCE AGAIN PRODUCE A PERIOD OF CRITICAL LEVEL RH OVER PORTIONS OF NORTH FLORIDA. AN HOUR OR TWO OF NEAR CRITICAL RH IS POSSIBLE ALONG THE I-75 CORRIDOR OF SOUTH-CENTRAL GEORGIA...HOWEVER CONFIDENCE IS HIGHER THAT EXTENDED DURATIONS OF THESE VALUES WILL NOT BE MET. ABUNDANT LOW LEVEL MOISTURE STREAMING NORTH AHEAD OF A COLD FRONT DURING WEDNESDAY WILL KEEP CONDITIONS WELL ABOVE CRITICAL LEVELS. SURFACE WINDS ARE ANTICIPATED TO BECOME QUITE GUSTY OUT OF THE SOUTH... ESPECIALLY WED AFTERNOON. A ROUND OF SHOWERS AND THUNDERSTORMS SHOULD CROSS THE REGION LATE WED AFTERNOON THROUGH WEDNESDAY NIGHT AHEAD OF THE COLD FRONT...WITH DRY AND COOL CONDITIONS TO FOLLOW FOR THE END OF THE WORKWEEK. && .TAE WATCHES/WARNINGS/ADVISORIES... AL...RED FLAG WARNING FROM NOON TODAY TO 5 PM CST THIS AFTERNOON FOR THE FOLLOWING ZONES: COFFEE...DALE...GENEVA...HENRY... HOUSTON. GA...RED FLAG WARNING FROM 1 PM TO 6 PM EST THIS AFTERNOON FOR THE FOLLOWING ZONES: BAKER...CALHOUN...CLAY...DECATUR... DOUGHERTY...EARLY...GRADY...LEE...MILLER...MITCHELL... QUITMAN...RANDOLPH...SEMINOLE...TERRELL...WORTH. FL...RED FLAG WARNING FROM NOON EST /11 AM CST/ TODAY TO 7 PM EST /6 PM CST/ THIS EVENING FOR THE FOLLOWING ZONES: BAY... CALHOUN...COASTAL WALTON...DIXIE...FRANKLIN...GADSDEN... GULF...HOLMES...INLAND WALTON...JACKSON...JEFFERSON... LAFAYETTE...LEON...LIBERTY...MADISON...TAYLOR...WAKULLA... WASHINGTON. FIRE WEATHER WATCH TUESDAY AFTERNOON FOR THE FOLLOWING ZONES: BAY...CALHOUN...COASTAL WALTON...DIXIE...FRANKLIN... GADSDEN...GULF...HOLMES...INLAND WALTON...JACKSON... JEFFERSON...LAFAYETTE...LEON...LIBERTY...MADISON...TAYLOR... WAKULLA...WASHINGTON. GM...NONE. && $$ UPDATE...GIBBS AVIATION...WATSON FIRE WEATHER...GOULD ####018006159#### FXUS61 KRLX 161414 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 909 AM EST MON FEB 16 2009 .SYNOPSIS... COLDER AIR STICKS AROUND THROUGH MONDAY NIGHT. HIGH PRESSURE MONDAY NIGHT AND TUESDAY...WITH MODERATING TEMPERATURES TUESDAY. A STRONG LOW PRESSURE SYSTEM WEDNESDAY. COLDER AIR AND SNOW SHOWERS THURSDAY. && .NEAR TERM /THROUGH TONIGHT/... FORECAST WAS UPDATED MAINLY FOR CLUSTER OF SNOW SHOWERS MARCHING ROUGHLY DOWN I-77 CORRIDOR. THIS COULD PRODUCE A QUICK LIGHT ACCUMULATION ON ROADS INCLUDING I-77...AND I-79 CHARLESTON EASTWARD TO ABOUT BRAXTON COUNTY...WHICH WILL THEN PROBABLY MELT WITH HEATING OF THE DAY AND HIGHER SUN ANGLES BY NOON. PREVIOUS DISCUSSION... MODELS CONTINUE TO SHOW COLD ADVECTION OVER THE REGION THIS MORNING WITH SOME LIMITED LOW LEVEL MOISTURE. WILL KEEP SOME SMALL SNOW SHOWER POPS AROUND AND NEAR THE MOUNTAINS. MOISTURE BECOMES THIN ENOUGH BY MID DAY THAT WILL ONLY GO WITH FLURRIES IN THE MOUNTAINS FOR THE AFTERNOON HOURS. MAV MOS HIGHS TODAY SEEM TOO HIGH...SO STAYED CLOSER TO THE FWC AND MET NUMBERS. GOOD RADIATION CONDITIONS TONIGHT AFTER CLOUDS CLEAR. BASED ON EXPECTED DEW POINTS...WENT BELOW MOS GUIDANCE. && .SHORT TERM /TUESDAY THROUGH THURSDAY NIGHT/... THE PERIOD BEGINS VERY QUIETLY AS HIGH PRESSURE REMAINS IN PLACE WITH SOME RIDGING ALOFT PROVIDING TRANQUIL CONDITIONS. THE ONLY ISSUE IS SOME HIGH CLOUDS THAT ARE SLIDING OVER THE RIDGE WHICH WILL SERVE TO HOLD TEMPERATURES DOWN A FEW DEGREES ACROSS THE NORTH...AND WITH THE MET/FWC WELL BELOW THE MAV DID TREND A LITTLE COOLER ACROSS NRN WV AND OHIO. BUT FURTHER SOUTH EXPECT MORE SUNSHINE AND DID GO CLOSER TO THE MAV THERE. STARTING TUESDAY NIGHT THROUGH THURSDAY NIGHT...WHILE THE MODEL DEPICT A SIMILAR PICTURE AS FAR AS THE EVOLUTION OF THE PATTERN...THERE ARE SOME DETAIL DIFFERENCE BETWEEN THE MODELS THAT ARE GIVING SOME TIMING PROBLEMS. OVERALL THE GFS IS FASTER THAN EVERY OTHER MODEL ON THE TIMING OF THE COLD FRONT WED NIGHT AND THE COLD NW FLOW ON THURSDAY...WITH THE LARGE CAMP OF MODELS A LITTLE SLOW HAVE TRIED TO GO CLOSER TO THE CONSENSUS. ON TUESDAY NIGHT THE CLOUDS WILL BE INCREASING AND HAVE START TO INTRODUCE SOME SLGT CHANCE POPS BY 6Z AND THEN QUICKLY RAMP THE POPS UP TO LIKELY IN THE SRN AND WRN COUNTIES BY 12Z. THE ONE CONCERN IS WITH THIS SYSTEM DO LIKE THE ONE THAT MOVED ACROSS THE REGION SATURDAY AND SPLIT WITH THE DYNAMICS NORTH AND THE MOISTURE SOUTH. WITH THIS SYSTEM STRONG...HAVE ELECTED TO FOLLOW THE MOS CONSENSUS WITH CAT POPS...BUT DID LOW THE QPF DOWN IN A LINE FROM HTS TO EKN/CKB THINKING THAT THERE COULD BE A WEAKNESS IN THE PCPN SHIELD. ONCE THIS INITIAL MOISTURE BOUNDARY PASSES...SHOULD SEE A BREAK IN THE SHOWERS AS THE REGION MOVES INTO THE WARM SECTOR. IT IS A THIS POINT THE FRONTAL TIMING COMES INTO PLAY SO HAVE REINTRODUCED A BAND OF LIKELY POPS WITH THE COLD FRONT MOVING IT ACROSS BETWEEN THE GFS AND NAM/ECMWF/CANADIAN TIMING. BEHIND THE FRONT...THE COLDER AIR WILL BE MOVING IN...BUT WITH THE DRY SLOT OVER THE AREA...FELT THAT ANY SNOW SHOWERS WOULD BE SCATTERED AT BEST AS THE MOISTURE LOOKS SUSPECT AND THE 850 MB TEMPERATURE REALLY LAG AND DO NOT SUPPORT THE UPSLOPE SNOW SHOWER ENVIRONMENT.. ON THURSDAY...WILL HAVE TO WAIT FOR THE COLD AIR AND DEEPER MOISTURE TO ARRIVE...WHICH SHOULD OCCUR DURING THE AFTERNOON AND CONTINUE INTO THE OVERNIGHT HOURS. HAVE INCREASED POPS LATE IN THE DAY AND THURSDAY NIGHT AS CONDITIONS BECOME EXTREMELY FAVORABLE FOR ACCUMULATING SNOW SHOWERS. WITH HAVE TO WATCH AS AN ADVISORY/WARNING SITUATION COULD DEVELOP IN THE NORTHERN AND CENTRAL MOUNTAINS OF WV. FOR TEMPERATURES...HAVE GENERALLY RUN CLOSE TO THE MAV/MEX NUMBERS FROM TUESDAY NIGHT ON...ALTHOUGH HAVE SOME CONCERN TEMPERATURES COULD BE HIGHER ON WED IF SOME SUN BREAKS OUT IN THE WARM SECTOR. ALSO WILL HAVE TO WATCH FOR FALLING TEMPS ON THURSDAY. && .LONG TERM /FRIDAY THROUGH SUNDAY/... INCREASED POPS WED NIGHT AND THURSDAY PER MODELS GOOD CONTINUITY ON LOW PRESSURE SYSTEM AFFECTING THE AREA THROUGH LATE THURSDAY. GFS/ECMWF SHOW SIMILAR QPF AND TEMPERATURES TIMING. ASSOCIATED STRONG COLD FRONT EXPECTED WED EVENING...AROUND 03Z THURSDAY WITH STRONG TEMPERATURE GRADIENT. PCPN SHOULD REMAIN LIQUID WED NIGHT...TRANSITIONING TO SNOW DURING THE PREDAWN HOURS THURSDAY ACROSS SOUTHEAST OH...NORTHERN WV AND EASTERN MOUNTAINS...TO SPREAD ACROSS THE REST OF THE AREA BY MID MORNING THURSDAY. INCREASE WIND GUSTS PER GFS SHOWING 50KTS AND ECMWF 35KTS AT H850. BUFKIT SHOWING MOMENTUM TRANSFER OUT OF THE GFS OF ABOUT 36KTS ALONG THE FRONT WED NIGHT. GOOD UPSLOPE CONDITIONS SET UP BEHIND THE FRONT THURSDAY NIGHT INTO FRIDAY UNDER DESCENT NORTHWEST FLOW...LOW LEVEL MOISTURE WITHING THE CRYSTAL GROWTH LAYER. USED A MIX OF HPC AND GMOS GUIDANCE FOR TEMPS THROUGH THE PERIOD. MODELS CONTINUE TO BRING A STRONG LOW PRESSURE SYSTEM NEXT WEEKEND. ADJUSTED CHANCE POPS FRIDAY NIGHT THRU SATURDAY NIGHT...EXITING GRADUALLY EXITING THE PCPN ACTIVITY OVER THE EASTERN MOUNTAINS SUNDAY. ALTHOUGH IT STILL FAR OUT...THIS SYSTEM WILL NEED TO BE MONITORED CLOSELY DUE TO THE POTENTIAL HIGH IMPACT IT POSES NEXT WEEKEND. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... MVFR CEILINGS AND SNOW SHOWERS ARE POSSIBLE THIS MORNING IN THE MOUNTAINS. MOSTLY VFR CONDITIONS CAN BE EXPECTED WEST OF THE MOUNTAINS. AS MOISTURE THINS DURING THE DAY...CONDITIONS WILL IMPROVE IN THE MOUNTAINS WITH CLOUDS DISSIPATING LATE THIS AFTERNOON AND EVENING. AVIATION OUTLOOK /BEYOND 06Z TUESDAY/... IFR CONDITIONS POSSIBLE WEDNESDAY NIGHT AND THURSDAY. IFR MAY LINGER OVER WV MOUNTAINS THURSDAY NIGHT INTO FRIDAY. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ARJ/ESS/RPY NEAR TERM...MDP/RPY SHORT TERM...ESS LONG TERM...ARJ AVIATION...RPY