426 FXUS62 KCHS 141301 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 901 AM EDT FRI JUN 14 2013 .SYNOPSIS... HIGH PRESSURE WILL BUILD OVER THE WEEKEND AND PERSIST INTO EARLY NEXT WEEK. A COLD FRONT WILL APPROACH FROM THE NORTHWEST BY THE MIDDLE OF NEXT WEEK AND POSSIBLY STALL OVER THE REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MORNING UPDATE... THE COLD FRONT HAS MOVED SOUTH OF THE CWA. DRIER AIR WILL ADVECT IN FROM THEN NORTH WITH DEWPOINTS STEADILY DROPPING THROUGHOUT THE DAY. IT WILL BE NOTICEABLY LESS HOT AND HUMID AS A RESULT WITH HIGHS ONLY RISING INTO THE UPPER 80S/AROUND 90 COMPARED TO MID- UPPER 90S THAT HAVE BEEN COMMON OVER THE PAST SEVERAL DAYS. SKIES WILL GRADUALLY CLEAR WITH MOSTLY SUNNY TO PARTLY CLOUDY SKIES DOMINATING AS WINDS TIP FROM NORTHWEST...TO NORTH AND EVENTUALLY NORTHEAST. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... TONIGHT...HIGH PRESSURE WILL BUILD STEADILY SOUTH INTO THE AREA TONIGHT AS UPPER RIDGING TAKES HOLD ALOFT. CLEAR SKIES...LIGHT WINDS AND FAIRLY LOW DEWPOINTS WILL PROMOTE MODEST RADIATIONAL CONDITIONS YIELDING SOME FAIRLY COOL LOWS COMPARED TO WHAT HAS BEEN OBSERVED OF LATE. LOWS WILL RANGE FROM THE LOWER 60S WELL INLAND TO THE LOWER 70S AT THE BEACHES WHERE INFLUENCES FROM THE WARMER ATLANTIC WATERS AND WEAK ONSHORE FLOW WILL HELP KEEP TEMPERATURES SOMEWHAT ELEVATED. SATURDAY AND SUNDAY...SURFACE HIGH PRESSURE WILL STEADILY DESCEND INTO THE REGION FROM THE NORTHWEST AND SETTLE INTO THE ATLANTIC OVER THE WEEKEND...WHILE UPPER LEVEL RIDGING BUILDS INTO THE SOUTHEAST STATES. THIS PATTERN WILL SUPPORT LARGE SCALE SUBSIDENCE THAT WILL EFFECTIVELY SUPPRESS CONVECTIVE DEVELOPMENT SATURDAY AND SUNDAY ACROSS THE FORECAST AREA. HAVE THUS INDICATED ZERO RAIN CHANCES BOTH DAYS UNDER MOSTLY CLEAR TO PARTLY CLOUDY SKIES. THICKNESS VALUES AGREE FAIRLY WELL WITH MODEL GUIDANCE REGARDING HIGH TEMPERATURES...AND EXPECT TEMPERATURES TO PEAK IN THE UPPER 80S TO AROUND 90 DEGREES AWAY FROM THE LOCALLY COOLER COASTLINE. MONDAY...HIGH PRESSURE AT THE SURFACE AND ALOFT WILL BEGIN TO RETREAT AS THE DAY PROGRESSES...AHEAD OF SHORTWAVE ENERGY AND AN ASSOCIATED SURFACE TROUGH APPROACHING FROM THE WEST. WILL REINTRODUCE A SLIGHT CHANCE OF THUNDERSTORMS MAINLY ACROSS INLAND AREAS...DUE TO UPSTREAM ACTIVITY POTENTIALLY SLIPPING INTO THE WESTERN ZONES. THE MAJORITY OF THE FORECAST AREA COULD REMAIN UNDER RESIDUAL CAPPING DURING THE DAYTIME HOURS. HIGH TEMPERATURES WILL REACH THE UPPER 80S TO LOWER 90S WITHIN INCREASING WARM SOUTHERLY FLOW. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... THE PATTERN WILL BECOME MORE UNSETTLED EARLY NEXT WEEK AND THROUGH MUCH OF THE EXTENDED FORECAST PERIOD. MEDIUM RANGE FORECAST MODELS SUGGEST THAT A BROAD UPPER TROUGH DEVELOPING OVER THE EAST COAST STATES WILL ALLOW A SERIES OF SHORTWAVES TO MOVE THROUGH THE REGION...SUPPORTING THE EVENTUAL PROGRESSION OF A BACKDOOR COLD FRONT INTO THE AREA BY THE MIDDLE OF NEXT WEEK. THE FRONT COULD STALL OVER THE FORECAST AREA AS IT BECOMES MORE PARALLEL TO FLOW ALOFT WEDNESDAY AND THURSDAY. IF THIS SCENARIO OCCURS...THEN THUNDERSTORM POTENTIAL WILL INCREASE FROM SLIGHT CHANCE MONDAY NIGHT AND EARLY TUESDAY INTO PERSISTENT 30 TO 40 PERCENT CHANCES FROM LATER TUESDAY THROUGH AT LEAST THURSDAY. PREFERRED TO REMAIN SOMEWHAT GENERIC THIS FAR IN ADVANCE...AND WILL REFINE DETAILS AS MODEL SOLUTIONS COME INTO BETTER AGREEMENT. HIGH TEMPERATURES WILL RANGE FROM THE UPPER 80S TO THE LOWER 90S AWAY FROM THE LOCALLY COOLER COASTLINE EACH AFTERNOON. && .AVIATION /13Z FRIDAY THROUGH TUESDAY/... VFR. EXTENDED AVIATION...NO CONCERNS. && .MARINE... TODAY...SOUTHWEST WINDS WILL TURN NORTH AND EVENTUALLY NORTHEAST TODAY IN THE WAKE OF A COLD FRONT. ELEVATED WINDS EARLY THIS MORNING AHEAD OF THE FRONT WILL SUBSIDE AS THE LOW-LEVEL JET PUSHES FARTHER EAST INTO THE OPEN ATLANTIC. BOTH WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA. TONIGHT...EAST TO NORTHEAST WINDS WILL DOMINATE THROUGH TONIGHT WITH BOTH WINDS AND SEAS REMAINING WELL BELOW ADVISORY THRESHOLDS. SATURDAY THROUGH TUESDAY...BENIGN CONDITIONS ARE EXPECTED OVER ALL COASTAL WATERS THROUGH THE WEEKEND...AS ATLANTIC HIGH PRESSURE BUILDS BEHIND A COLD FRONT SHIFTING FAR OUT TO SEA. WINDS WILL QUICKLY VEER FROM EAST TO SOUTHEAST ON SATURDAY...BECOMING PREVAILING SOUTH/SOUTHEAST THROUGH EARLY NEXT WEEK. WINDS AND SEAS WILL THEN STEADILY INCREASE/BUILD OVER ALL WATERS BY LATE MONDAY...AS THE PRESSURE GRADIENT TIGHTENS BETWEEN LOW PRESSURE ADVANCING TO THE NORTHEASTERN UNITED STATES AND HIGH PRESSURE OVER THE WESTERN ATLANTIC. CONDITIONS SHOULD STILL REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THROUGH THE PERIOD...WITH WINDS PEAKING BETWEEN 15 TO 20 KT AND SEAS UP TO 4 TO 5 FT...HIGHEST BEYOND 10 NM FROM THE COAST. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM...BDC/ST SHORT TERM...ST/WMS LONG TERM...WMS AVIATION...BDC/ST MARINE...BDC/ST/WMS