000 FXUS62 KGSP 091336 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 936 AM EDT THU OCT 9 2008 .SYNOPSIS... A LOW PRESSURE SYSTEM WILL MOVE SLOWLY SOUTHEAST ACROSS GEORGIA TO THE GEORGIA FLORIDA COASTLINE FRIDAY AND DISSIPATE. MEANWHILE...A BACK DOOR COLD FRONT WILL PUSH SOUTH ACROSS THE REGION FRIDAY NIGHT INTO EARLY SATURDAY. HIGH PRESSURE WILL BUILD SOUTH DOWN THE EASTERN SEABOARD BEHIND THE FRONT ON SATURDAY AND REMAIN THROUGH EARLY NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... CLOSED UPPER LOW WILL SLOWLY MOVE FROM THE AL/GA BORDER TO THE GA/FL COAST LATE TONIGHT. DEFORMATION ZONE ROTATES AROUND THIS LOW ACROSS THE AREA AND COMBINED WITH WEAK LL UPSLOPE FLOW WILL BE THE MAIN FORCING FOR PRECIP TODAY. KEPT LIKELY POPS ALONG AND S OF I-85...TAPERING TO CHANCE N. STILL LOOKING FOR WEAK INSTABILITY THIS AFTN ACROSS S CWA SO LEFT SLIGHT CHANCE TSTMS THERE. TWEAKED HOURLY T/DP/RH AND WINDS...LEFT AFTN HIGHS 70-75...COOLER MTNS. DEFORMATION ZONE SHIFTS TO THE SRN PORTIONS OF THE CWFA DURING THE EVENING...BEFORE MOVING SOUTH OVERNIGHT. HIGHEST PRECIP CHANCES WILL BE MAINTAINED THERE. SHOWERS AND DRIZZLE WILL CONTINUE NORTH OF THERE WITH COPIOUS LOW LEVEL MOISTURE AND WEAK UPSLOPE FLOW. WEAK INSTABILITY CONTINUES THRU THE EVENING OVER THE EXTREME SRN CWFA. WILL KEEP ISOLATED THUNDER THERE. LOWS WILL BE QUITE MILD ONCE AGAIN AROUND 60 MOST AREAS. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 315 AM THURSDAY...THE GFS WILL REMAIN THE MODEL OF CHOICE THROUGH THE SHORT TERM PERIOD. ON FRIDAY...THE CLOSED H5 LOW WILL WEAKEN AND MOVE OFF THE GS/SC COAST. AS THE LOW WEAKENS...RIDGING WILL BUILD NORTHEAST ACROSS THE CWA...WITH H5 HEIGHTS REACHING 588DM. AT THE SFC...HIGH PRESSURE CENTERED OVER NEW ENGLAND WILL NOSE SOUTHWEST ACROSS THE WESTERN CAROLINAS...PUSHING A WEAK BACKDOOR COLD FRONT INTO WESTERN CAROLINAS BETWEEN 18Z FRI - 0Z SAT. FORECAST SOUNDINGS INDICATE THAT CAPES VALUES MAY RANGE FROM 300-700 J/KG BY 21Z FRI. I WILL FORECAST ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP ACROSS THE CWA BY MID DAY. SKY COVER SHOULD REMAIN MOSTLY CLOUDY...LIKELY KEEPING TEMPERATURES LIMITED TO LOW TO MID 70S. FRIDAY NIGHT THROUGH SATURDAY...MID LEVEL RIDGE AND SFC HIGH WILL CONTINUE TO EXPAND ACROSS THE CWA. DRIER AIR WILL BUILD NORTHEAST TO SOUTHWEST ACROSS THE NC FOOTHILLS AND PIEDMONT...HOWEVER...LLVL AND CIRRUS LEVEL MOISTURE WILL KEEP SKY COVER AT LEAST PARTLY CLOUDY. DEEPER MOISTURE AND UPSLOPE FLOW MAY CONTINUE TO SUPPORT SCT TO ISO SHRA DURING THE NIGHT. AFTER SUNRISE...ONLY ISO SHOWERS ACROSS THE UPSTATE AND NE GA ARE EXPECTED. INCREASING INSOLATION AND REDUCE SHRA COVERAGE WILL RESULT IN WARMER TEMPERATURES ON SATURDAY...WITH LOW TO MID 70S ACROSS THE MTNS AND U70S EXPECTED ACROSS THE FOOTHILLS AND PIEDMONT. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... AS OF 330 AM THURSDAY...RIDGING WILL STRENGTHEN ACROSS THE CWA FROM SUNDAY THROUGH TUESDAY. SKY COVER WILL BECOME PARTLY TO MOSTLY CLEAR WITH MUCH DRIER LOW TO MID LEVEL MOISTURE VALUES. TEMPERATURES THROUGH THE PERIOD SHOULD REMAIN SEVERAL DEGREES ABOVE NORMAL...PEAKING ON TUESDAY WITH LOWS IN THE LOW TO MID 50S TO HIGHS AROUND 80. ON WEDNESDAY...THE 0Z GFS INDICATES THAT A WEAK COLD FRONT WILL REACH THE SOUTHERN APPALACHIANS BY MID DAY ON WEDNESDAY. INCREASE CLOUD COVER AND ISOLATED MTN SHOWERS MAY ACCOMPANY THE FRONT. TEMPERATURES WILL REMAIN SLIGHTLY ABOVE NORMAL...RANGING FROM MID 70S ACROSS THE MTN VALLEYS TO U70S EAST. && .AVIATION /14Z THURSDAY THROUGH MONDAY/... RESTRICTIONS RANGE FROM IFR TO MVFR ACROSS THE AREA THIS MORNING. WILL KEEP RESTRICTIONS AS IS THRU MID MORNING...THEN SLOWLY RAISE CIGS TO HIGH MVFR BY AFTERNOON. GUIDANCE SUGGESTING LOW VFR BY AFTERNOON. HOWEVER...GIVEN THE LOW LEVEL FLOW AND MOISTURE CONCERNED GUIDANCE IS IMPROVING THINGS TOO FAST. SHOWERS SHOULD REDEVELOP BY AFTERNOON...WITH SOME THUNDER POSSIBLE SC SITES. CONDITIONS RETURN TO LOW MVFR THEN IFR OVERNIGHT WITH INCREASING ELY FLOW AND CONTINUED LOW LEVEL MOISTURE. OUTLOOK...LOW LEVEL MOISTURE WILL REMAIN IN PLACE ACROSS THE REGION AS LOW PRESSURE LINGERS NEAR THE SOUTHEAST COAST AND HIGH PRESSURE BUILDS OVER TO THE NORTH THROUGH THE WEEKEND. THIS WILL LIKELY LEAD TO DIURNAL DEVELOPMENT OF FOG AND LOW CLOUDS WITH LONG DURATION IFR/MVFR CONDITIONS EXPECTED FROM MIDNIGHT TO NOON EACH DAY. SOME DRYING IS INDICATED EARLY NEXT WEEK AS HIGH PRESSURE BUILDS IN MORE STRONGLY FROM THE NORTH. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...TJB NEAR TERM...RWH/RB SHORT TERM...NED LONG TERM...NED AVIATION...RWH