907 FXUS62 KCHS 280149 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 949 PM EDT THU MAR 27 2014 .SYNOPSIS... HIGH PRESSURE WILL STEADILY DRIFT OFF THE MID ATLANTIC COAST TONIGHT WHILE LOW PRESSURE APPROACHES THE AREA FROM THE WEST THROUGH FRIDAY NIGHT. A COLD FRONT WILL MOVE THROUGH THE AREA AND OFFSHORE LATE SATURDAY...WITH HIGH PRESSURE THEN BUILDING OVER THE REGION THROUGH THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... MAINLY CLEAR SKIES ALONG AND NORTH OF I-16 THIS EVENING WITH A SHIELD OF CIRROSTRATUS STREAMING OVER SOUTH GEORGIA. MOISTURE RETURN IN THE LOWER LEVELS RUNNING A BIT SLOWER THAN EARLIER MODEL PROJECTIONS TO THIS POINT...THUS WE MADE SOME SKY COVER ADJUSTMENTS FOR THE NEXT SEVERAL HOURS TO TREND. OVERNIGHT...DRY WEATHER SHOULD PREVAIL WITH ONLY A SMALL RISK FOR ISOLATED SHOWERS NEAR THE SOUTH CAROLINA COAST BY DAYBREAK. WE LOWERED MIN TEMPS A BIT MANY AREAS GIVEN THE STRONGER INITIAL RADIATIONAL COOLING AND LATEST SURFACE OBSERVATIONS. BY LATE TONIGHT...READINGS COULD RISE A FEW DEGREES AS CLOUDS INCREASE. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... FRIDAY... ATLANTIC HIGH PRESSURE WILL MAINTAIN A MOISTENING SOUTHERLY FLOW ACROSS THE AREA. THE BEST CHANCE OF SHOWERS...AND MAYBE A THUNDERSTORM...WILL BE OVER THE ATLANTIC WATERS AND ALONG THE SC COAST IN THE MORNING. LATER IN THE DAY THE BEST CHANCE WILL LIKELY BE ALONG THE GA COAST AND FARTHER INLAND AS AN AREA OF PRECIP MOVES IN FROM THE WEST WHERE THE DEEPER MOISTURE WILL BE FOUND. ALTHOUGH SKIES SHOULD BE RATHER CLOUDY TEMPERATURES SHOULD STILL REACH THE LOWER TO MID 70S AWAY FROM THE LOCALLY COOLER COASTAL AREAS. A BIT MORE UNCERTAINTY ENTERS THE FORECAST FRIDAY NIGHT AS MUCH DEPENDS ON THE TIMING/STRENGTH OF SHORTWAVES ALOFT. IN GENERAL WE STILL THINK COASTAL SC AND INTERIOR AREAS WILL SEE THE BEST CHANCES. THE CLOUDS AND HIGHER DEWPOINTS WILL KEEP LOW TEMPS GENERALLY AROUND 60. SATURDAY...A STRONGER UPPER SHORTWAVE TROUGH MOVING TOWARD THE OHIO VALLEY WILL CAUSE A SURFACE COLD FRONT TO MOVE TOWARD SOUTHEAST SC/GA DURING THE DAY. SHOWERS AND THUNDERSTORMS WILL BE LIKELY ALONG AND AHEAD OF THE FRONT WHICH SHOULD BE NEAR THE COAST TOWARD EVENING. WIND FIELDS WILL BE ELEVATED AND THERE SHOULD BE SUFFICIENT INSTABILITY IN PLACE FOR SOME STRONG TO POSSIBLY SEVERE STORMS. CONFIDENCE IN SEVERE WEATHER OVERALL IS STILL LOW GIVEN THE UNCERTAINTY IN CLOUD COVER/POSSIBLE SEA FOG ALONG THE COAST AS WELL AS FAIRLY WEAK MID-LEVEL INSTABILITY. PREFER TO WAIT TO INTRODUCE INTO THE HAZARDOUS WEATHER OUTLOOK FOR NOW BUT ANYONE WITH OUTDOOR PLANS ON SATURDAY SHOULD CLOSELY MONITOR THE FORECAST. TEMPS COULD PUSH 80 IN A FEW SPOTS GIVEN SOME PRE-FRONTAL CONVERGENCE BUT MUCH DEPENDS ON AMOUNT OF CLOUD COVER. PRECIP WILL BE ENDING FROM WEST TO EAST EARLY SATURDAY EVENING AS THE FRONT PUSHES OFFSHORE ALLOWING COOLER AND DRIER AIR TO FILTER IN. LOWS SHOULD BE IN THE UPPER 40S/AROUND 50 INLAND BY DAYBREAK SUNDAY. SUNDAY...COOL/DRY AIRMASS WILL BE IN PLACE SUNDAY BEHIND THE DEPARTING COLD FRONT...ALTHOUGH THERE IS SOME UNCERTAINTY IN HOW CHILLY IT WILL BE GIVEN THE TIMING OF THE UPPER TROUGH. HIGHS WILL LIKELY BE A BIT BELOW NORMAL...GENERALLY AROUND 70 MOST LOCALES...ESPECIALLY ACROSS GEORGIA. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... MEDIUM RANGE GUIDANCE IS IN VERY GOOD AGREEMENT THROUGH THE LONG TERM PERIOD. MID AND UPPER LEVEL RIDGING WILL BUILD ALOFT EARLY IN THE WEEK AS SURFACE HIGH PRESSURE SETTLES OVER THE SOUTHEAST STATES ON MONDAY THEN SHIFTS INTO THE WESTERN ATLANTIC ON TUESDAY. THE RIDGE ALOFT WILL FLATTEN SOME DURING THE MIDDLE OF THE WEEK AS A WEAK BACKDOOR COLD FRONT APPROACHES BUT STALLS NORTH OF THE AREA WEDNESDAY. THE RIDGING ALOFT WILL AMPLIFY FURTHER LATE IN THE WEEK ALLOWING THE STALLED FRONT TO LIFT NORTHWARD...MEANWHILE ATLANTIC HIGH PRESSURE WILL PREVAIL AS A COLD FRONT APPROACHES FROM THE WEST ON THURSDAY. AS FOR SENSIBLE WEATHER...EXPECT THE RIDGING ALOFT...SURFACE HIGH AND LIMITED MOISTURE TO RESULT IN RAIN-FREE CONDITIONS THROUGH MOST OF THE LONG TERM PERIOD. HOWEVER...THERE IS A SLIGHT CHANCE FOR SHOWERS AND THUNDERSTORMS BY THURSDAY AS THE COLD FRONT NEARS. TEMPERATURES START OFF NEAR NORMAL EARLY NEXT WEEK...THEN GRADUALLY WARM ABOVE NORMAL THROUGH THE LONG TERM PERIOD. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... VFR CONDITIONS SHOULD CONTINUE TO PREVAIL AT BOTH KCHS AND KSAV THROUGH 00Z SATURDAY...ALTHOUGH THERE ARE INCREASING CHANCES FOR MVFR CIGS LATER TONIGHT THEN PERIODICALLY ON FRIDAY AS LOW LEVEL MOISTURE BUILDS. BREEZY CONDITIONS WILL DEVELOP AFTER MIDDAY ON FRIDAY WITH SOUTHERLY SURFACE WINDS CLOSE TO 15 KT BY MID AFTERNOON WITH GUSTS UP TO 25 KT. BRIEF SHOWERS ARE POSSIBLE AROUND KCHS LATE TONIGHT AND FRIDAY MORNING BUT COVERAGE POTENTIAL AND MODEL PROGS BOTH SUGGEST LOW CONFIDENCE OF OCCURRENCE AROUND THE TERMINAL. DEEPER MOISTURE INVADES LATE IN THE TAF PERIOD AFTER 20Z FRIDAY AND SHOWER CHANCES EXPECTED TO ALSO INCREASE. UPCOMING TAF RELEASES WILL LIKELY BEGIN TO INTRODUCE RAIN MENTIONS AFTER THAT TIME. EXTENDED AVIATION OUTLOOK...LOW CHANCES FOR PERIODIC FLIGHT RESTRICTIONS IN SHOWERS/THUNDERSTORMS FRIDAY NIGHT THROUGH SATURDAY. OTHERWISE...VFR CONDITIONS TO PREVAIL THROUGH TUESDAY. BREEZY CONDITIONS LIKELY FRIDAY THROUGH SUNDAY...MAINLY DURING THE AFTERNOON. && .MARINE... OVERNIGHT...A FAIRLY ENHANCED PRESSURE GRADIENT WILL REMAIN OVER THE COASTAL WATERS ALONG THE SOUTHWESTERN EDGE OF HIGH PRESSURE SHIFTING FURTHER OFF THE MID ATLANTIC COAST AND INTO THE WESTERN ATLANTIC. HOWEVER...WINDS/SEAS SHOULD REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THROUGH THE OVERNIGHT PERIOD. IN GENERAL...WINDS SHOULD PEAK BETWEEN 15-20 KT BEYOND 10 NM FROM THE COAST. AN EASTERLY SWELL ALONG THE SOUTHERN PERIPHERY OF THE HIGH WILL SUPPORT GRADUALLY BUILDING SEAS FROM 3-4 FT TO 4-5 FT...HIGHEST OVER OUTER GEORGIA WATERS. FRIDAY THROUGH TUESDAY...ATLANTIC HIGH PRESSURE WILL EVENTUALLY GIVE WAY TO A COLD FRONT SATURDAY EVENING WITH COOLER/DRIER HIGH PRESSURE RETURNING EARLY NEXT WEEK. EXPECT BREEZY CONDITIONS FRIDAY THROUGH THE WEEKEND WITH SEAS HOVERING NEAR 5 FT BUT THE CHANCE OF ADVISORIES APPEAR LOW FOR NOW...BEST CHANCES BEING BEYOND 20 NM. THE POST-FRONTAL SURGE SATURDAY NIGHT INTO SUNDAY SHOULD PRODUCE THE BEST CHANCE FOR ADVISORIES. MUCH MORE TRANQUIL CONDITIONS THEN EXPECTED THROUGH TUESDAY. AS LOW-LEVEL MOISTURE INCREASES OVER THE WATERS AHEAD OF THE COLD FRONT FRIDAY INTO SATURDAY WE WILL NEED TO WATCH FOR THE POTENTIAL FOR SOME SEA FOG DEVELOPMENT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ SYNOPSIS... NEAR TERM... SHORT TERM...RJB LONG TERM...JAQ AVIATION... MARINE...