000 FXUS61 KRLX 150456 AFDRLX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON WV 1256 AM EDT WED APR 15 2009 .SYNOPSIS... WEAK SURFACE LOW PRESSURE PUSHES EAST TONIGHT...FOLLOWED BY AN UPPER LEVEL SYSTEM WEDNESDAY. HIGH PRESSURE IS IN CONTROL THURSDAY INTO SATURDAY FOR DRY WEATHER. ANOTHER LOW BRINGS UNSETTLED WEATHER NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... MINOR CHANGES FOR EVENING UPDATE. WITH NO SIGN OF THUNDER IN SHOWERS...AND INSTABILITY DECREASING WITH LOSS OF SOLAR HEATING...HAVE TAKEN OUT MENTION OF THUNDER THIS EVENING. ALSO...TWEAKED HIGHER POPS FURTHER WEST THIS EVENING TO ACCOUNT FOR APPARENT FRONT OVER EASTERN KENTUCKY AS SEEN BY LINE OF SHOWERS AND DROP IN DEWPOINTS BEHIND IT. BELIEVE A PRE FRONTAL SURFACE TROUGH IS CURRENTLY MOVING ACROSS WEST VIRGINIA AT TIME. PREVIOUS DISCUSSION... SURFACE LOW WILL CONTINUE TO MOVE THROUGH THE REGION TODAY...FOLLOWED BY THE UPPER LEVEL LOW TONIGHT. MODELS CONTINUE TO INDICATE WEAK INSTABILITY OVER THE FORECAST AREA...AS WELL AS SPC DAY 1 CONVECTIVE OUTLOOK HAS GENERAL THUNDERSTORMS OVER THE FORECAST AREA. HAVE THEREFORE CONTINUED TO MAINTAIN THUNDERSTORMS IN THE FORECAST THIS AFTERNOON AND EVENING ACROSS THE FORECAST AREA. INVERTED TROUGH ROTATES ACROSS OHIO THIS EVENING BEFORE STALLING/SETTING UP ACROSS NORTHERN WEST VIRGINIA/SOUTHEASTERN OHIO. THIS BOUNDARY WILL BE THE MAIN FOCUS FOR POPS ACROSS THE REGION OVERNIGHT...BUT SHOWERS WILL CONTINUE TO REMAIN OVER THE ENTIRE FORECAST AREA AS THE UPPER LEVEL LOW MOVES INTO THE REGION OVERNIGHT. MODELS INDICATING H850 TEMPS NEAR ZERO OVER SOUTHERN WEST VIRGINIA WEDNESDAY MORNING. THE HIGHER PEAKS MAY SEE A FEW FLAKES OF SNOW WEDNESDAY MORNING. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/... PESKY UPPER LEVEL LOW WILL DRIFT EASTWARD THROUGH THE LOWER GREAT LAKES...BEFORE DIPPING SOUTHEAST INTO THE CENTRAL APPALACHIANS AND HEADING OFF THE EAST COAST. WITH NO CHANGE IN AIRMASS...WILL BE SOCKED INTO DEEP LOW LEVEL MOISTURE THROUGH LATE WEDNESDAY NIGHT. VARIOUS UPPER LEVEL VORTICES AND SOME MODEST MID LOW LEVEL DEFORMATIONS WILL KEEP THE CHANCES FOR SHOWERS GOING THROUGH THIS TIMEFRAME...BEFORE THE MOISTURE IS SCOURED OUT WITH A DRIER NORTHEAST FLOW AT THE SURFACE. ALONG WITH GENERALLY LOWER CHANCES FOR SHOWERS...NOT INCLUDING THE HIGHER ELEVATIONS WHERE A BIT OF UPSLOPE ENHANCEMENT IS POSSIBLE...ADDED DRIZZLE TO THE GRIDS GIVEN A MOISTURE DEPTH TO AROUND 750HPA. THURSDAY WILL BE A VAST IMPROVEMENT WITH THE SKY CLEARING...SETTING UP FOR A GOOD RADIATIONAL COOLING NIGHT THURSDAY NIGHT. A REBOUND IS SET UP FOR FRIDAY WITH A GOOD AMOUNT OF APRIL SUN...GETTING THE TEMPERATURES BACK TO NORMAL OR SLIGHTLY ABOVE. COULD SEE SOME FAIR WEATHER CUMULUS FORMATION ON FRIDAY...BUT WILL ALSO HAVE THE POSSIBILITY OF MIXING DOWN SOME DRIER AIR DURING DAYTIME HEATING...WITH LOW SURFACE DEWPOINTS. WILL NEED TO WATCH FIRE WEATHER INTERESTS AT THIS TIME WITH FUELS DRYING OUT RAPIDLY ON FRIDAY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... GENERALLY FOLLOWED HPC THINKING FOR THIS PORTION OF THE FORECAST. BEGINNING OF PERIOD...FRIDAY NIGHT INTO SATURDAY NIGHT...SHOULD BE DRY AS HIGH PRESSURE IS IN CONTROL. LOW PRESSURE WITH E-W ORIENTED WARM FRONT WILL APPROACH FROM THE WEST SATURDAY NIGHT INTO MONDAY...BRINGING A PERIOD OF UNSETTLED WEATHER. PER HPC GUIDANCE...HAVE BUMPED POPS TO LIKELY ACROSS PORTIONS OF THE REGION FROM SUNDAY INTO MONDAY. MODELS INDICATE SOME MARGINAL INSTABILITY WILL DEVELOP SUNDAY NIGHT...ACROSS SOUTHERN PORTIONS OF THE FORECAST AREA...AND HAVE ADDED SLIGHT CHANCE POPS FOR THUNDERSTORMS. LOW WILL PUSH EAST ON MONDAY...DRAGGING A COLD FRONT WITH IT. AS THIS FEATURE PUSHES AWAY...PRECIPITATION CHANCES SHOULD DECREASE. HOWEVER...ANOTHER SYSTEM...AT THE SURFACE AND ALOFT...WILL APPROACH FROM THE WEST TUESDAY...RESULTING IN MORE UNSETTLED WEATHER. HPC TEMPERATURE GUIDANCE WAS USED WITH SOME MINOR TWEAKING. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... 06Z WEDNESDAY THRU 06Z THURSDAY... WEAK UPPER LEVEL LOW PRESSURE SYSTEM WILL PUSH SOUTHEAST THROUGH THE PERIOD. ABUNDANT LOW LEVEL MOISTURE IS EXPECTED TO REMAIN IN PLACE INTO TONIGHT...BEFORE DRIER AIR BEGINS TO TAKE CONTROL NORTH LATE. EXPECT IFR/LIFR CONDITIONS IN RAIN SHOWERS/DRIZZLE SHOULD DOMINATE THE REGION THROUGH MUCH OF THE PERIOD. THE EXCEPTIONS WILL BE BETWEEN 06Z AND 09Z WHERE SOME MVFR CONDITIONS ARE STILL POSSIBLE... AND THEN AGAIN THIS AFTERNOON ACROSS THE LOWLANDS WHERE CIGS MAY LIFT INTO THE MVFR CATEGORY. WITH ABUNDANT MOISTURE IN PLACE AND LIGHT WINDS...EXPECT CONDITIONS TO ONCE AGAIN DETERIORATE TO IFR BETWEEN 00Z AND 06Z. AVIATION OUTLOOK /BEYOND 06Z THURSDAY/... IFR CONDITIONS ARE POSSIBLE BETWEEN 06Z AND 14Z THURSDAY...ESPECIALLY FOR THE CENTRAL AND SOUTHERN MOUNTAINS. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...NONE. OH...NONE. KY...NONE. VA...NONE. && $$ SYNOPSIS...26/JSH/SL NEAR TERM...JMV SHORT TERM...26 LONG TERM...JSH AVIATION...JSH