000 FXUS62 KGSP 100303 AFDGSP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC 1003 PM EST THU FEB 9 2012 .SYNOPSIS... HIGH PRESSURE WILL REMAIN IN COMMAND OVER THE REGION THROUGH FRIDAY. A COLD FRONT WILL MOVE ACROSS THE REGION FRIDAY NIGHT THROUGH MID DAY ON SATURDAY. THEN ANOTHER AREA OF HIGH PRESSURE WILL BUILD BACK IN SATURDAY EVENING AND REMAIN INTO MONDAY. THE NEXT FRONT WILL APPROACH THE AREA LATE ON TUESDAY. && .NEAR TERM /THROUGH FRIDAY/... AS OF MID EVENING...FAIR WEATHER ACROSS THE WESTERN CAROLINAS AND NE GEORGIA. FCST FOR THE OVERNIGHT HOURS APPEARS TO BE ON TRACK...OTHER THAN OVERLY PESSIMISTIC CLOUD COVER...WHICH HAS BEEN LESSENED ON THIS UPDATE. TEMPS LOOK OK. REMAINDER OF PREVIOUS DISCUSSION... ON FRIDAY...RETURN FLOW LOW CLOUDS AND EVEN SOME SHRA ACTIVITY WILL APPROACH FROM THE SE DURING THE AFTN HOURS. SCT SHRA MAY DEVELOP AS FAR WEST AS I-77 WITH THIS FORCING. OTHERWISE...MID LEVEL CLOUDS WILL THICKEN AND LOWER DURING THE COURSE OF THE DAY WITH SHRA ALSO POSSIBLE ALONG THE TN LINE BY THE LATE AFTN HOURS. THE AIRMASS WILL BE QUITE MILD...THOUGH CLOUD COVER IS LIKELY TO HOLD MAX TEMPS IN THE MID TO UPPER 50S FOR THE MOST PART. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... AT 140 PM THURSDAY...RAIN SHIELD ASSOCIATED WITH SURFACE LOW SPINNING UP OFF THE SOUTHEAST COAST COULD BRUSH FAR EASTERN PORTIONS OF THE FORECAST AREA FRIDAY EVENING...SO SLIGHT/LOW CHANCE POPS WILL BE CARRIED TO ACCOUNT FOR THIS. OTHERWISE...WEAK COLD ADVECTION WILL COMMENCE OVER THE HIGH TERRAIN AS THE CYCLONE DEEPENS OFF THE COAST. MEANWHILE...ARCTIC FRONT ASSOCIATED WITH POTENT NORTHERN STREAM SHORT WAVE TROUGH WILL APPROACH THE AREA LATE FRIDAY NIGHT/EARLY SATURDAY. THE MODELS SUGGEST THERE WILL BE ENOUGH LINGERING MOISTURE IN ADVANCE OF THIS FRONTAL SYSTEM TO SUPPORT LIKELY POPS ACROSS THE WESTERN MTNS BY LATE FRI EVENING. ENOUGH COLD AIR WILL SPILL INTO THE MTNS DURING THIS TIME THAT ANY PRECIP WOULD FALL AS SNOW ABOVE 4000 FEET OR SO FRI EVENING...WITH A RAIN/SNOW MIX POSSIBLE AS LOW AS 2500 FEET. ARCTIC FROPA WILL OCCUR BY LATE SATURDAY MORNING/EARLY AFTERNOON... WITH TEMPS DROPPING RAPIDLY IN MOST AREAS DURING THE AFTERNOON. MEANWHILE...A NW FLOW SNOW EVENT WILL UNFOLD SATURDAY...AS UPSLOPE MOISTURE LINGERS NEAR THE TENN BORDER. THE SETUP WILL ACTUALLY BE QUITE FAVORABLE FOR ACCUMULATING SNOW SHOWERS SATURDAY...AS ORTHOGONAL H8 FLOW OF 30-40 KT (WITH TRAJECTORIES OFF THE GREAT LAKES)...STEEP LOW LEVEL LAPSE RATES...AND VERY COLD H8 TEMPS OF LESS THAN -10 ARE EXPECTED WITHIN THE MOIST NW FLOW REGIME ACROSS THE WESTERN MTNS. LIKELY POPS WILL BE CARRIED ALONG THE TENN BORDER THROUGH THE DAY. WE WILL BEGIN TO MENTION THE POTENTIAL FOR ACCUMULATING SNOWFALL FRI NIGHT AND SATURDAY IN THE HWO. NW FLOW SNOW SHOWERS WILL TAPER OFF BY SATURDAY EVENING...LEAVING BEHIND A VERY COLD END TO THE SHORT TERM PORTION OF THE FORECAST... AS A DEEP TROUGH BECOMES ESTABLISHED OVER THE EASTERN CONUS. TEMPS SAT NIGHT/SUNDAY WILL BE AMONG THE COLDEST OF THE SEASON SO FAR...WITH MOST LOCATIONS EXPECTED TO AVERAGE 10-15 DEGREES BELOW NORMAL. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... AS OF 130 PM THURSDAY...THE MEDIUM RANGE FORECAST BEGINS AT 00Z ON MONDAY WITH A DEEP UPPER TROUGH AXIS MOVING FARTHER OFF THE EASTERN SEABOARD AND BROAD UPPER RIDGING MOVING OVER THE REGION IN ITS WAKE. A DECENT UPPER SHORTWAVE WILL APPROACH THE CAROLINAS EARLY TUESDAY AND MOVE EAST OF THE AREA BY EARLY WED. ANOTHER ROUND OF UPPER RIDGING BUILDS IN AFTERWORDS ON WED AND LINGERS UNTIL THE NEXT LONGWAVE TROF MOVES TOWARDS THE FCST AREA AT THE VERY END OF THE PERIOD LATE THURSDAY INTO FRIDAY. AT THE SFC...DRY WEATHER WITH COOLER TEMPERATURES ARE EXPECTED OVER THE REGION AS A BROAD SURFACE HIGH WILL BE IN PLACE OVER THE SOUTHEAST ON MONDAY. LOW LVL FLOW WILL BECOME SOUTHERLY LATE MONDAY AND TUES WITH A LARGE AREA OF MOIST...LOW TO MID LVL AIR ASSOCIATED WITH A WEAK MESO LOW MOVING OVER THE REGION. HIGH PRESSURE WILL BUILD BACK IN ON WED AND DRY THINGS OUT WITH PREDOMINATELY DOWNSLOPE FLOW. A STRONGER SFC LOW AND ITS ASSOCIATED FRONT WILL APPROACH THE CWFA AT THE VERY END OF THE PERIOD. THINGS WILL BE DRY ON MONDAY WITH POPS RAMPING UP TO SOLID CHANCE TUES MORNING. I KEEP THEM AT SLIGHT CHANCE ON WED AND THEN RAMP THEM BACK UP ON THURS. TEMPS WERE NOT CHANGED MUCH FROM THE PREVIOUS FCST WITH VALUES STEADILY INCREASING THRU WED AND THEN MODERATING TOWARDS THE END OF NEXT WEEK. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... AT ALL SITES INCLUDING KCLT...VFR CONDITIONS EXPECTED THROUGH THE PERIOD. WINDS WILL BE LIGHT AND SOUTHERLY MOST OF THE PERIOD WITH THE DIRECTION BECOMING MORE SWLY BY TOMORROW AFTERNOON. CEILINGS ARE EXPECTED TO GRADUALLY LOWER AFTER ABOUT 18Z WITH KAVL POSSIBLY DECREASING TO AROUND 5000FT BY THE END OF THE TAF PERIOD. OUTLOOK...A COLD FRONT WILL MOVE OVER THE FCST AREA FROM THE NORTHWEST EARLY SATURDAY. STILL EXPECT THE BEST CHANCE FOR RESTRICTIONS WILL BE AT KAVL WITH FROPA AND JUST BEHIND IT EARLY SATURDAY. DRY HIGH PRESSURE WILL BUILD BACK IN SUNDAY THROUGH MONDAY. AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)... WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM && .GSP WATCHES/WARNINGS/ADVISORIES... GA...NONE. NC...NONE. SC...NONE. && $$ SYNOPSIS...PAT NEAR TERM...MCAVOY/PM SHORT TERM...JDL LONG TERM...JPT AVIATION...JPT/PM