233 FXUS62 KCHS 161141 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 741 AM EDT TUE JUL 16 2013 .SYNOPSIS... HIGH PRESSURE WILL CONTINUE TO BUILD THROUGH THE MID WEEK PERIOD AND PERSIST INTO THE WEEKEND. A TROUGH OF LOW PRESSURE WILL APPROACH THE AREA FROM THE NORTHWEST EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... FOG AND STRATUS HAVE BECOME FAIRLY WIDESPREAD ALONG AND W OF I-95 AND WE PUNCHED OUT A RECENT UPDATE THAT INITIALIZED WITH PATCHY FOG THIS MORNING INLAND ZONES. SOME LOCALIZED VSBYS MAY BRIEFLY FALL TO 1 MILE OR LESS AT TIMES UNTIL THE LOW CLOUDS DISSIPATE AROUND 12Z. THE DEEP LAYERED RIDGE TO THE N TODAY WILL SLOWLY RETROGRADE TO THE W WHILE A WEAK AND PARTIALLY DIFFUSE COLD FRONT DROPS INTO NORTH CAROLINA LATE IN THE DAY. FORECAST SOUNDINGS SUGGEST ARE BEST CHANCES FOR SCATTERED DIURNAL CONVECTION WITH THE SEA BREEZE TODAY IS OVER INLAND ZONES IN SE GEORGIA AND EVEN THERE...THE SHOWER AND STORM POTENTIAL LOOKS FAIRLY MARGINAL. CONVECTION MANY AREAS THIS AFTERNOON LOOKS TO BE FAIRLY SPARSE AS MID LEVEL CAPPING SPREADS SW OVER THE REGION AND MOISTURE PROFILES BECOMING LESS IMPRESSIVE WITH TIME. FOR MOST AREAS...WE HAVE JUST SLIGHT CHANCE POPS CONFINING LOW END CHANCE POPS A LITTLE FURTHER S ACROSS SE GEORGIA WHERE 850 MB THETA-E RIDGING WANING WITH TIME. HIGH TEMPS WILL BE AROUND 90 MOST AREAS AWAY FROM THE BEACHES AND BARRIER ISLANDS TODAY. WE RAISED READINGS UP A DEGREE OR SO BORDERING THE MIDLANDS AND PEE DEE GIVEN THERMAL PROFILES THERE. LIGHTER WINDS ALONG THE COASTAL HALF OF THE FORECAST AREA TODAY. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... PRETTY QUIET WEATHER ON TAP TONIGHT. THE ONLY FEATURE WE WILL BE WATCHING IS THE WEAK BACKDOOR FRONT WELL TO THE N. SW FLOW OVER THE NE QUARTER OF SOUTH CAROLINA WILL BE ADVECTING SOME LOW LEVEL MOISTURE TOWARD THE SANTEE COOPER LAKES. CANNOT RULE OUT AN ISOLATED OVERNIGHT SHOWER OR TSTM OVER THAT REGION...OTHERWISE DRY CONDITIONS WITH FEW TO SCATTERED CLOUDS. WEDNESDAY THROUGH FRIDAY...A LARGE AND DEEP AREA OF HIGH PRESSURE WILL BUILD OVER THE MIDWEST THROUGH THURSDAY...KEEPING DEEP MOISTURE INLAND AND A MORE TYPICAL SUMMERTIME PATTERN OVER THE SOUTHEASTERN UNITED STATES AS THE AREA REMAINS ALONG THE WESTERN EDGE OF ATLANTIC HIGH PRESSURE. HIGH PRESSURE WILL THEN BEGIN TO WEAKEN OVER THE SOUTHEAST ON FRIDAY AS A LARGE TROUGH ADVANCES INTO THE NORTHERN GREAT LAKES REGION WHILE A WEAK MID LVL WAVE ROUNDS THE WESTERN EDGE OF ATLANTIC HIGH PRESSURE OVER THE NORTHERN GULF OF MEXICO. DESPITE A LACK OF DEEP MOISTURE ON WEDNESDAY...WILL MAINTAIN A SLIGHT CHANCE OF SHOWERS AND/OR THUNDERSTORMS ALONG AN AFTERNOON SEABREEZE DURING PEAK HEATING HOURS...ESPECIALLY OVER INLAND AREAS IN SOUTHEAST SOUTH CAROLINA. PRECIP CHANCES SHOULD GRADUALLY INCREASE ON THURSDAY AS LEE TROUGHING BEGINS TO DEVELOP OVER THE MIDLANDS WHILE ONSHORE FLOW PERSISTS...BUT MOST ACTIVITY SHOULD REMAIN WEST OF THE FORECAST AREA AND DISSIPATE SHORTLY AFTER SUNSET. ON FRIDAY...PRECIP CHANCES WILL CONTINUE TO INCREASE TO THE 20-40 POP RANGE AS RIDGING BEGINS TO WEAKEN OVER THE SOUTHEAST. SHOWER AND THUNDERSTORM COVERAGE SHOULD BE GREATEST OVER SOUTHEAST GEORGIA AS A WEAK MID LVL WAVE ROUNDS THE WESTERN EDGE OF ATLANTIC HIGH PRESSURE OVER THE NORTHERN GULF OF MEXICO. AT THIS TIME...THE SEVERE WEATHER POTENTIAL WILL REMAIN LOW INTO EARLY WEEKEND. OVERALL HIGH TEMPS WILL WARM A FEW DEGREES THROUGH LATE WEEK WITH HIGH PRESSURE DOMINATING THE PATTERN AND AT LEAST PARTLY SUNNY SKIES IN PLACE. EXPECT AFTERNOON HIGH TEMPS TO RANGE BETWEEN THE UPPER 80S TO LOWER 90S. OVERNIGHT LOWS WILL RANGE IN THE LOW 70S INLAND TO MID/UPPER 70S ALONG THE COAST. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... HIGH PRESSURE WILL PREVAIL TO START THE WEEKEND BUT WILL GRADUALLY WEAKEN INTO EARLY NEXT WEEK AS A TROUGH OF LOW PRESSURE ADVANCES FROM THE GREAT LAKES REGION TO THE MID ATLANTIC AND SOUTHEASTERN UNITED STATES. ONSHORE FLOW AND LEE TROUGHING OVER THE MIDLANDS WILL BE THE MAIN CONTRIBUTORS TO CHANCES OF AFTERNOON SHOWERS AND THUNDERSTORMS ON SATURDAY. CHANCES OF PRECIP WILL INCREASE ON SUNDAY AS LEE TROUGHING BECOMES ENHANCED OVER THE MIDLANDS. GREATEST COVERAGE SHOULD OCCUR INLAND NEAR THE LEE TROUGH. PRECIP COVERAGE SHOULD PEAK ON MONDAY AND TUESDAY AS A COLD FRONT SLOWLY ADVANCES INTO NORTHERN PORTIONS OF THE FORECAST AREA BEFORE SHIFTING OFFSHORE. && .AVIATION /12Z TUESDAY THROUGH SATURDAY/... FOG/STRATUS DEVELOPED INLAND AND BRUSHING KSAV ONCE AGAIN AROUND DAYBREAK PRODUCING LIFR CONDITIONS ACROSS THE NW PORTION OF CHATHAM COUNTY. THE LOW CLOUDS SHOULD BREAK QUICKLY MID MORNING WITH BOTH TERMINALS GENERALLY VFR WITH PATCHY MORNING MVFR CIGS FROM CUMULUS FIELDS. RAIN CHANCES PRETTY LOW WITH VCSH/VCTS AT KSAV POSSIBLE LATE MORNING AND EARLY AFTERNOON. CONVECTION INLAND AFTER MID AFTERNOON. TONIGHT...VFR....BUT SMALL CHANCES OF LIGHT FOG AT THE TERMINALS TOWARD DAYBREAK ON WED. CANNOT RULE OUT LOW CIGS AT KSAV AGAIN AROUND DAYBREAK BUT CONFIDENCE QUITE LOW AT THIS STAGE. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH LATE WEEK OUTSIDE ISOLATED TO SCATTERED TSRA AT BOTH TERMINALS. CHANCES OF MVFR CIGS/VSBYS SHOULD INCREASE EARLY NEXT WEEK WITH THE APPROACH OF A TROUGH FROM THE NORTHWEST. && .MARINE... SURFACE RIDGE AXIS WILL BE GRADUALLY BUILDING INTO THE SAVANNAH RIVER ENTRANCE REGION LATER TODAY THROUGH TONIGHT. PERSISTENT ONSHORE FLOW WILL WEAKEN AND VEER TO SW OVER CAROLINA WATERS WITH WEAK ONSHORE FLOW PERSISTING OVER GEORGIA LEGS. SPEEDS WILL BE MAINLY LESS THAN 15 KT WITH SEAS 3 TO 4 FT TODAY SUBSIDING TO 2 TO 3 FT TONIGHT. WEDNESDAY THROUGH SUNDAY...ATLANTIC HIGH PRESSURE WILL DOMINATE THE WATERS THROUGH LATE WEEK. IN GENERAL...SOUTH/SOUTHEAST WINDS WILL WILL REMAIN AT OR BELOW 15 KT WITH SEAS BETWEEN 1-3 FT...HIGHEST OVER OUTER GEORGIA WATERS. SOUTH/SOUTHWEST WINDS AND SEAS SHOULD GRADUALLY INCREASE/BUILD OVER THE WEEKEND AS A TROUGH OF LOW PRESSURE APPROACHES THE WATERS FROM THE NORTHWEST INTO EARLY NEXT WEEK. HOWEVER...CONDITIONS SHOULD REMAIN BELOW SMALL CRAFT ADVISORIES DURING THIS TIME PERIOD. RIP CURRENTS...STILL A 4 FT SWELL AT GRAYS REEF SHORTLY BEFORE DAWN THIS MORNING. WE ADJUSTED WAVES IN THE SURF ZONE A BIT HIGHER DURING THE FIRST HALF OF TODAY. DIMINISHING SWELL THIS AFTERNOON BUT WE FELT A LOW-END MODERATE RISK ALONG THE GEORGIA COAST WAS PRUDENT GIVEN THE LATEST READINGS AT THE OFFSHORE BUOYS. WATERSPOUTS...GIVEN VERY LIGHT WIND FIELDS AND THE FORMATION OF THE LAND BREEZE BOUNDARY EARLY WEDNESDAY MORNING...TRANSITIONING TO THE INLAND PROGRESSING SEA BREEZE...WE/LL NEED TO KEEP WATCH FOR THE POSSIBILITY OF WATERSPOUTS THROUGH MIDDAY WEDNESDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...DPB LONG TERM...DPB AVIATION... MARINE...DPB