000 FXUS62 KCHS 070010 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 810 PM EDT MON JUL 6 2009 .SYNOPSIS... A COLD FRONT WILL DROP SOUTHWARD THROUGH THE REGION LATE TONIGHT AND TUESDAY. THE FRONT IS THEN EXPECTED TO STALL OUT ACROSS SOUTHERN GEORGIA TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...WITH HIGH PRESSURE THEN BUILDING IN FROM THE NORTH INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... A SURFACE FRONT CURRENTLY ACROSS NORTHERN SC STRETCHING EAST INTO SOUTHEAST NC WILL SLOWLY SINK SOUTHWARD TONIGHT. MEANWHILE A SERIES OF SHORTWAVES WILL TRAVERSE SOUTHERN GEORGIA AND OFF THE SOUTHEAST COAST. SCATTERED SHOWERS AND STORMS THAT HAVE DEVELOPED ACROSS INLAND AREAS IN ASSOCIATION WITH SURFACE HEATING WILL CONTINUE TO TRACK THROUGH THE AREA THROUGH EARLY THIS EVENING. ONCE THE BOUNDARY LAYER COOLS LATER THIS EVENING...FORCING FOR PRECIPITATION WILL MAINLY EXIST WITH SHORTWAVE ENERGY CROSSING THE SOUTHERN HALF OF THE AREA. THEREFORE WE HAVE THE HIGHER POPS IN SOUTHEAST GEORGIA AND EXTREME SOUTHERN SC. SINCE SOME WEAK UPPER JET DIVERGENCE WILL REMAIN IN PLACE TONIGHT...ANY AREA COULD SEE SOME SHOWERS. SEVERE WEATHER POTENTIAL NOW APPEARS QUITE LOW DUE TO THE LACK OF ORGANIZATION AMONG CONVECTION AND A VERY MOIST PROFILE. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... THE FRONT SHOULD BISECT THE FORECAST AREA BY DAYBREAK TUESDAY WITH SOME DRIER AIR FILTERING INTO THE TRI-COUNTY AREA. CONVECTION IS EXPECTED TO BE FOCUSED ALONG AND SOUTH OF THE FRONT IN THE HIGHER THETA-E AIRMASS AND WITH THE ASSISTANCE OF SOME WEAK SHORTWAVE ENERGY. FARTHER NORTH...ACTIVITY SHOULD BE FAIRLY ISOLATED. THUS HAVE LIKELY POPS FAR SOUTH AND OVER THE WATERS DURING THE DAY WITH LOW-END CHANCE FARTHER NORTH. CONSIDERABLE CLOUD COVER SHOULD PERSIST THROUGH LATE MORNING BEFORE SOME BREAKS BEGIN IN SPOTS. HIGHS WILL BE AROUND 90 MOST AREAS. TUESDAY NIGHT...KEPT A CHANCE FOR RAIN ACROSS SOUTHERN PORTIONS WITH DRY CONDITIONS IN THE TRI-COUNTY AREA WHERE A SIGNIFICANTLY MORE STABLE AIRMASS WILL RESIDE. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... MEDIUM RANGE GUIDANCE IS IN FAIRLY GOOD AGREEMENT THROUGH THE LONG TERM PERIOD. GENERAL MODEL CONSENSUS IS FOR A WEAKENING FRONTAL BOUNDARY TO DROP INTO SOUTHERN GEORGIA ON WEDNESDAY...AND REMAIN NEARLY STATIONARY INTO WEDNESDAY NIGHT. A BUILDING UPPER LEVEL RIDGE OF HIGH PRESSURE OVER THE SOUTHERN PLAINS COMBINED WITH SURFACE HIGH PRESSURE BUILDING FROM THE NORTH WILL PUSH THE FRONT FARTHER SOUTH THURSDAY INTO FRIDAY. HOWEVER...THERE IS STILL SOME INDICATION FROM THE GFS...ECMWF AND CANADIAN THAT A WAVE...OR SEVERAL WAVES...OF WEAK LOW PRESSURE WILL TRACK ALONG THE FRONT OFF THE SOUTHEAST COAST IN THE THURSDAY AND FRIDAY TIME PERIOD. A RETURN TO A MORE TYPICAL SUMMERTIME PATTERN WILL OCCUR FOR THE WEEKEND AS THE UPPER LEVEL RIDGE EXTENDS EASTWARD OVER THE SOUTHEAST STATES AND ATLANTIC HIGH PRESSURE PREVAILS. THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS WILL DIMINISH EACH DAY AS THE WORK WEEK PROGRESSES...WITH THE GREATEST CHANCES REMAINING OVER THE SOUTHERN PORTION OF THE FORECAST AREA...OR IN CLOSER PROXIMITY TO THE FRONTAL BOUNDARY. DIURNAL...MAINLY ISOLATED CONVECTION IS EXPECTED BY THE WEEKEND AND THIS PATTERN SHOULD LAST INTO EARLY NEXT WEEK. TEMPERATURES WILL BE NEAR OR PERHAPS A DEGREE OR TWO BELOW NORMAL TUESDAY THROUGH FRIDAY WITH A SYNOPTIC ONSHORE FLOW IN PLACE. TEMPERATURES SHOULD RISE ABOVE NORMAL AS RIDGING BUILDS OVER THE REGION SATURDAY THROUGH MONDAY. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... MAIN CONCERN WILL BE SHOWERS CONTINUING NEAR THE CHS TERMINAL EARLY TONIGHT FOLLOWED BY MVFR CIGS AT BOTH TERMINALS LATE TONIGHT INTO EARLY MORNING. AT THIS TIME...BELIEVE SHOWERS WILL CONTINUE TO DIMINISH WHILE APPROACHING THE CHS TERMINAL...THEREFORE HAVE KEPT MENTION OF ANY PRECIP OUT OF THE CHS TAF FOR NOW. THERE WILL REMAIN A CHANCE OF SHOWERS AT BOTH TERMINALS OVERNIGHT...BUT CONFIDENCE REMAINS TOO LOW TO PUT IN TAFS. SOUTHWEST WINDS AROUND 10 KNOTS WILL BECOME 5 TO 10 KNOTS AT BOTH TERMINALS TONIGHT. THIS IN COMBINATION WITH A MOIST BOUNDARY LAYER WILL PRODUCE TEMPO MVFR CIGS BETWEEN 08Z AND 15Z AT BOTH TERMINALS. CONDITIONS WILL IMPROVE TO VFR BY MID MORNING TUESDAY AS CLOUD COVER BEGINS TO BREAK. NORTHWEST AT OR BELOW 10 KNOTS WILL BECOME SOUTHWEST DURING THE AFTERNOON. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE GENERALLY EXPECTED TO PREVAIL OUTSIDE OF ISOLATED/SCATTERED CONVECTION TUE THROUGH SAT. && .MARINE... A CONTINUED 30-35 KT LOW-LEVEL JET ACROSS THE GA WATERS TONIGHT WILL ALLOW SEAS TO BUILD TO 6 FT OVER FAR OUTER PORTIONS BY MIDNIGHT. A VEERING FLOW LATE TONIGHT AND ON TUESDAY WITH DECREASING SPEEDS WILL BRING SEAS BACK BELOW 6 FT AND DECREASING SURFACE WINDS. HAVE MAINTAINED THE SMALL CRAFT ADVISORY FOR THE OFFSHORE GA WATERS FOR TONIGHT. WEDNESDAY THROUGH SATURDAY...A FRONT WILL STALL OUT NEAR OR JUST SOUTH OF THE GEORGIA COASTAL WATERS INTO THURSDAY. HIGH PRESSURE WILL THEN BUILD IN FROM THE NORTH THROUGH SATURDAY. WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA THROUGH THE PERIOD. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EDT TUESDAY FOR AMZ374. && $$