000 FXUS61 KRLX 221745 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1245 PM EST SAT DEC 22 2007 .SYNOPSIS... A HIGH PRESSURE SYSTEM WILL PROVIDE MILD WEATHER TODAY. A STRONG COLD FRONT WHIPS THROUGH ON SUNDAY. GUSTY WINDS CAN BE EXPECTED SUNDAY AFTERNOON. HIGH PRESSURE AND DRY WEATHER ARRIVE FOR CHRISTMAS EVE AND CHRISTMAS DAY. && .NEAR TERM /THROUGH TONIGHT/... SE WINDS CONT TO DO THEIR THING SCOURING OUT LOW CLOUDS AND USHERING IN WARMER WX. ADJUSTED SKY GRIDS DOWN A LTL THROUGH EARLY AFTN THEN INC THEM. MAXT ON TRACK...WITH LOW CLOUDS OUT OF BKW MID 40S SEEMS GOOD THERE. MAV MOS WINDS LOOK WAY TOO LIGHT COMPARED TO PRESSURE GRADIENT AND CURRENT WINDS...SO WENT CLOSER TO NAM MOS WINDS. WENT BELOW MOS GUIDANCE AT BKW DUE TO SOUTHEAST UPSLOPE WINDS. WENT WITH THE HIGHER MOS GUIDANCE ON THE WESTERN SLOPE LOCATIONS DUE TO DOWN SLOPE WARMING. COLD FRONT APPROACHES FROM THE WEST TONIGHT...SO INCREASED POPS LATE IN THE NIGHT. ALSO RAN A NON DIURNAL TEMPERATURE TRACE WITH COOLEST TEMPERATURES IN THE EVENING HOURS. && .SHORT TERM /SUNDAY THROUGH TUESDAY/... TIMING OF THE COLD FRONT AGAIN IS THE BIG PLAYER ON SUNDAY AS THE MODELS CONTINUE TO SHOW THAT THE FRONT WILL BE JUST WEST OF THE REGION AT 12Z SO HAVE HELD CAT POPS FROM PKB TO HTS AND WEST AT 12Z AND THEN MOVE THEM ACROSS THE REGION AT ABOUT 35 TO 40 KTS AS THE STRONG WINDS ALOFT SWEEP THE FRONT THROUGH THE AREA. SHOULD SEE VERY GUST WINDS ALONG THE FRONT AND BEHIND IT SUNDAY AFTERNOON. 850 MB WINDS AT AROUND 50 KTS SHOULD BE ABLE TO MIX DOWN SOME SO HAVE SOME GUST TO AROUND 40 KTS IN THE LOWLANDS BEHIND THE FRONT. IN ADVANCE OF THE FRONT THE WINDS ARE EVEN STRONG...BUT TYPICALLY THOSE WINDS DO NOT REACH THE SURFACE EXCEPT ALL THE RIDGE TOPS IN THE MOUNTAINS...GENERALLY ABOVE 3000 FT. BUT WITH THAT SAID GUST TO 40 KTS WOULD LEAD TO WIND ADVISORY CRITERIA...MOST LIKELY ACROSS ERN OHIO AND NRN WV SUNDAY AFTERNOON. FOR NOW WILL LEAVE FOR THE DAY SHIFT TO HOIST SINCE IT WOULD BE A THIRD PD ADVISORY. WILL HIGHLIGHT THREAT IN THE HWO FOR NOW. TEMPERATURES ARE TRICKY AS IN ADVANCE OF THE FRONT AND RAIN...WHICH SHOULD BE COINCIDENTAL...THE TEMPERATURES SHOULD GET QUITE A BOOST IN THE 50S...AND THEN FALL DURING THE AFTERNOON HOURS. THUS HAVE LEANED TOWARD THE WARMER MAV ON SUNDAY. ON SUNDAY NIGHT...THE LOW OVER THE GREAT LAKES CONTINUES TO SPIN...BUT THE FLOW ACROSS THE REGION REMAINS WEST TO WSW AND WITH THERE BEING LITTLE MOISTURE ADVECTING IN FROM THE LAKES OR WRAP AROUND...DO NOT SEE MUCH IN THE WAY OF UPSLOPE PRECIPITATION OR CLOUDS FOR THAT MATTER. EXPECT MOST OF THESE CLOUDS TO REMAIN ACROSS NRN OH AND PA SO HAVE GONE DRY ON SUNDAY NIGHT INTO MONDAY WITH LESS CLOUDS. FOR TEMPERATURES...THE MAV AND MET WERE VERY CLOSE ON SUNDAY NIGHT WHILE THE FWC WAS MUCH COLDER. THOUGHT THAT WITH THE WIND STILL BLOWING THE COLDER FWC WAS TOO COLD SO WENT WITH A BLEND OF THE MAV AND MET. ON MONDAY...DESPITE THE SUN AROUND...THE WEAK FLOW AND LACK OF MIXING...WITH THE SUN SO WEAK THIS TIME OF YEAR...FELT THE COOL MET WAS THE WAY TO GO AS THE 850 TEMPERATURES DID NOT SUPPORT THE WARMER MAV. ON MONDAY NIGHT INTO TUESDAY...THE NEW MODELS...SAVE THE 00 NAM...SUPPORT A SLOWER MOVEMENT OF THE UPPER LOW OUT OF THE LOWER MISSISSIPPI VALLEY. THEY WERE ALSO A LITTLE STRONGER WITH THIS FEATURE...BUT FURTHER SOUTH WITH THE MOISTURE. SO HAVE LIMITED ANY MENTION OF POPS TO THE EXTREME SOUTH ACROSS THE COAL FIELDS AND SOUTHERN MOUNTAINS. BUT COULD EASILY SEE IT BEING DRY. ALSO THE MOISTURE AT LOW LEVELS WAS NEARLY NON EXISTENT...SO JUST EXPECTING SOME HIGH CLOUDS ON CHRISTMAS DAY. SO THE CHANCES FOR A WHITE CHRISTMAS LOOK LIKE SLIM TO NONE AT THIS STAGE. FOR TEMPERATURES...THOUGHT THE MEX NUMBERS WERE CLOSE SO ADJUSTED THAT DIRECTION. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... WHILE THROUGH WEDNESDAY THE MODELS ARE IN AGREEMENT...BEYOND THAT POINT THEY REALLY BEGIN TO DIVERGE. ON TUESDAY NIGHT...WITH HIGH PRESSURE STILL AROUND AND THE UPPER LEVEL SHORTWAVE NOW EXITING EAST OF THE AREA...SHOULD BEGIN TO SEE SOME UPPER LEVEL RIDGING BUILD EAST. THIS SHOULD CONTINUE THE DRY WEATHER THROUGH WEDNESDAY. THE MEX TEMPERATURES LOOKED REASONABLE BOTH PERIODS SO HAVE TRENDED THE FORECAST THAT DIRECTION. FROM WEDNESDAY NIGHT ON...THE MODELS ARE HANDLING EACH SYSTEM DIFFERENTLY WITH THE GFS MUCH QUICKER TO BRING A LOW PRESSURE SYSTEM WITH GOOD MOISTURE ACROSS THE REGION WEDNESDAY NIGHT AND EXIT THURSDAY MORNING. MEANWHILE...THE ECMWF WITH SLOWER AND WEAKER WITH THIS SYSTEM. SO FOR NOW HAVE ALLOWED THE LOW CHANCE POPS TO RIDE...MAINLY FROM 6Z THROUGH THE DAY ON THURSDAY...MORE IN LINE WITH THE ECMWF. BUT FOR FRIDAY...THE GFS SHOWS HIGH PRESSURE IN PLACE WITH UPPER LEVEL RIDGING HOLD IN STRONG. THE ECWMF ON THE OTHER HAND BRINGS ANOTHER CLOSED LOW OUT OF THE SOUTHERN ROCKIES AND WRAPS UP ANOTHER 985 MB LOW INTO THE GREAT LAKES BY SATURDAY MORNING. WITH THIS HAS SEEMED TO BE THE EARLY WINTER STORM TRACK...FOR NOW WILL HOLD ON TO THE PREVIOUS FORECAST OF SLIGHT TO LOW CHANCE POPS ON SUNDAY...BUT COULD EASILY SEE THE NEED TO INCREASE POPS IF THIS PATTERN PERSIST IN THE ECMWF. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... SE WINDS DOING THEIR THING EATING AWAY AT ANY ENCROACHMENT OF LOW CLOUDS. OTHER THAN CI AND OCNL MID DECK DO NOT EXPECT ANY CIG RESTRICTIONS UNTIL 10Z AT PKB-HTS...CRW-CKB 12Z...MTNS 14-15Z. OF COURSE...BKW SHOULD STAY MVFR UNTIL THIS EVNG WHEN SE WINDS VEER TO THE S. BRIEF IFR WX WITH RW AHEAD OF THE COLD FRONT SUN MRNG. BOUNDARY REACHES THE OHIO RIVER APPROX 16Z WITH IT KNOCKING ON THE DOOR AT CKB AND CRW BY 18Z. GUSTY WINDS ARE PREDICTED THE ENTIRE PD. GUST UPWARDS OF 30KTS ARE PSBL THE LAST SIX HRS OF THE FCST. AVIATION OUTLOOK /BEYOND 18Z SUNDAY/ VERY GUSTY WEST WINDS ALONG AND BEHIND THE COLD FRONT SUN AFTN AND EVNG. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...ESS/RPY NEAR TERM...29 SHORT TERM...ESS LONG TERM...ESS AVIATION...29