Area Forecast Discussion
Issued by NWS Charleston, SC

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KCHS 191745 AFDCHS AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1245 PM EST FRI DEC 19 2014 .SYNOPSIS...
-- Changed Discussion --
WEAK HIGH PRESSURE WILL PREVAIL THIS AFTERNOON AND THIS EVENING. UNSETTLED WEATHER IS EXPECTED LATER TONIGHT THROUGH TUESDAY NIGHT AS SEVERAL DISTURBANCES SHIFT OVER THE REGION. A STRONG COLD FRONT WILL EVENTUALLY SHIFT THROUGH THE AREA WEDNESDAY WITH DRYER CONDITIONS TO FOLLOW THROUGH LATE WEEK.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
EARLY FRIDAY AFTERNOON...SATELLITE IMAGERY DEPICTED A GRADUAL DIMINISHING COVERAGE TREND OF MID/HIGH LEVEL CLOUDS CROSSING THE AREA. THUS FAR...CLOUDS HAVE LIMITED TEMPERATURE RECOVERY...BUT A GENERAL INCREASE IN INSOLATION SHOULD STILL ALLOW TEMPS TO PUSH INTO THE LOWER TO MID 60S.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... VERY FAST UPPER FLOW ACROSS THE SOUTHEAST STATES CONTINUES TO MAKE FOR A TRICKY FORECAST INTRODUCING POPS TONIGHT. ALTHOUGH MODELS MAINTAIN SIMILAR QPF TIMING FROM PREVIOUS RUNS... A SOMEWHAT QUICKER PROGRESSION OF RAINS IS POSSIBLE AND WE HAD TO MAKE ONLY MINOR ADJUSTMENTS FROM OUR PREVIOUS THINKING GIVEN CONSENSUS OF CONDENSATION DEFICIT PROGS AND INITIAL ARRIVAL OF UPPER FORCING. SPRINKLES AND PATCHY LIGHT RAINS MAY BREAK OUT IN THE EVENING HOURS IN A FEW AREAS TO THE WEST OF I-95 BUT MUCH HIGHER CONFIDENCE RAINS EXPAND AFTER 06Z WITH CATEGORICAL POPS LATE AS SUNRISE ARRIVES SATURDAY. OVERNIGHT QPF SHOULD MAINLY BE LIGHT WITH VERTICAL PROFILES ONLY MOISTENING UP SIGNIFICANTLY LATER IN THE NIGHT. CLOUDS AND RAIN WILL HELP TO ANCHOR A WEAK WEDGE PATTERN AT THE SURFACE WITH LOWS 40-45 NORTH AND MID 40S S OF I-16. SATURDAY...A WET DAY REMAINS IN THE FORECAST AS ISENTROPIC ASCENT LIFTS MOISTURE OVER A WEDGE OF HIGH PRESSURE AT THE SFC. ACTIVITY WILL LIKELY BE ONGOING INTO AT LEAST EARLY AFTERNOON WHILE FORCING PERSISTS FROM A H5 SHORTWAVE PASSING OVER THE SOUTHEAST AND A STRONG UPPER LVL JET POSITIONED OVER MUCH OF THE SOUTHERN UNITED STATES. HOWEVER...THE MID/UPPER PATTERN SUGGESTS A QUICKLY PACED EVENT THAT OFFERS LESS PRECIP ACCUMULATION...WITH PERHAPS JUST A FEW TENTHS OF INCH OVER MOST AREAS. PRECIP SHOULD END FROM WEST TO EAST DURING THE EVENING AS THE DEEPEST MOISTURE SHIFTS OFFSHORE. OVERALL TEMPS WILL BE COOLER WITHIN THE WEDGE AND UNDER CLOUDY SKIES. EXPECT TEMPS TO PEAK IN THE LOWER 50S IN SOUTHEAST SOUTH CAROLINA AND MID/UPPER 50S IN SOUTHEAST GEORGIA. WE COULD SEE A FEW LOCATIONS REACH 60 IN OUR MOST SOUTHERN ZONES. SATURDAY NIGHT...WE SHOULD SEE A PERIOD OF DRY WEATHER...BUT MOISTURE WILL BEGIN INCREASING FROM THE SOUTH AHEAD OF ANOTHER WAVE OF LOW PRESSURE SHIFTING/DEVELOPING OVER THE NORTHEAST GULF OF MEXICO. LOW TEMPS SHOULD RANGE IN THE LOW/MID 40S...COOLEST OVER INLAND SOUTHEAST SOUTH CAROLINA. TEMPS SHOULD BE SLIGHTLY WARMER ALONG THE IMMEDIATE COAST. SUNDAY...THE DAY SHOULD START OFF MOSTLY DRY...BUT MODELS ARE IN GENERAL AGREEMENT THAT MOISTURE WILL BUILD FROM THE SOUTH AS AN AREA OF LOW PRESSURE OVER THE NORTHEAST GULF OF MEXICO SLOWLY SHIFTS OVER THE SOUTHEASTERN UNITED STATES SUNDAY AFTERNOON AND NIGHT. HAVE THEREFORE INDICATED 20-30 POPS IN SOUTHEAST GEORGIA SPREADING INTO SOUTHEAST SOUTH CAROLINA SUNDAY EVENING AND THEN INCREASING UPWARDS TO AROUND 70 POPS SUNDAY NIGHT FOR ALL AREAS AS THE LOW TRACKS OVER OR IMMEDIATELY ALONG THE SOUTHEAST COAST. GREATEST CHANCES OF PRECIP APPEAR TO BE OVER SOUTHEAST GEORGIA AND ALONG THE SOUTH CAROLINA COAST AT THIS TIME...ESPECIALLY AS A SERIES OF H5 SHORTWAVES SHIFT OVER THE AREA SUNDAY NIGHT. OVERALL HIGH TEMPS WILL BE DEPENDENT ON THE TRACK OF THE SFC LOW...BUT SHOULD REACH THE MID/UPPER 50S OVER MOST LOCATIONS AWAY FROM THE COAST. TEMPS COULD PEAK IN THE LOWER 60S ALONG COASTAL AREAS IN SOUTHEAST GEORGIA. OVERNIGHT LOWS SHOULD RANGE IN THE MID/UPPER 40S AWAY FROM THE COAST...AND IN THE LOW 50S ALONG THE COAST. MONDAY...SHOWERS WILL LIKELY BE ONGOING TO START OFF THE DAY AS AN AREA OF LOW PRESSURE CONTINUES TO MAKE WAY TO THE NORTHEAST. MOST PRECIP SHOULD SHIFT OFFSHORE BY THE AFTERNOON...BUT CHANCES OF SHOWERS WILL REMAIN IN THE FORECAST THROUGH MUCH OF THE EVENING WHILE ABUNDANT LOW-LVL MOISTURE LAGS BEHIND THE LOW TO THE NORTHEAST. TEMPS WILL BE DEPENDENT ON WHAT IS LEFT OF THE WEDGE INLAND...BUT SHOULD BE SLIGHTLY WARMER...IN THE UPPER 50S INLAND TO LOWER 60S IN SOUTHEAST GEORGIA AND ALONG THE SOUTH CAROLINA COAST. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... MONDAY NIGHT INTO TUESDAY NIGHT...THE PATTERN WILL REMAIN UNSETTLED AS AHEAD OF COLD FRONT THAT EVENTUALLY PUSHES THROUGH THE SOUTHEAST EARLY WEDNESDAY. AT THIS TIME...MODELS SUGGEST CHANCES OF PRECIP INCREASING MONDAY NIGHT INTO TUESDAY AS A WARM FRONT TRIES TO LIFT NORTH INTO A WEAKENING WEDGE OF HIGH PRESSURE AT THE SFC. A PERIOD OF WARMING SHOULD ALSO OCCUR WITHIN A SOUTHERLY FLOW AHEAD OF THE APPROACHING COLD FRONT TO THE WEST. HAVE THEREFORE INTRODUCED SHOWERS FOR ALL AREAS...RATHER THAN RAIN. WE COULD SEE ENOUGH INSTABILITY TO INCLUDE A FEW THUNDERSTORMS IN THE FORECAST SHOULD TRENDS PERSIST...MAINLY IN SOUTHEAST GEORGIA TUESDAY AFTERNOON AND EVENING. OVERALL HIGH TEMPS SHOULD RANGE IN THE LOW/MID 60S FOR MOST AREAS ON TUESDAY...EVEN WITH CLOUD COVER PRESENT. UPPER 60S ARE EXPECTED OVER SOUTHEAST GEORGIA. CHANCES OF PRECIP SHOULD QUICKLY DIMINISH AS THE COLD FRONT BEGINS TO SHIFT THROUGH THE AREA LATE TUESDAY NIGHT. TUESDAY NIGHT LOWS SHOULD RANGE IN THE UPPER 40S TO AROUND 50 OVER MOST AREAS. WEDNESDAY THROUGH FRIDAY...A MUCH QUIETER/DRY PERIOD OF WEATHER IS ANTICIPATED AS HIGH PRESSURE BUILDS OVER THE REGION BEHIND A COLD FRONT SHIFTING OFFSHORE EARLY WEDNESDAY. TEMPS WILL BE SLOW TO WARM THROUGH THURSDAY...UNTIL HIGH PRESSURE BECOMES MORE CENTERED OVER THE WESTERN ATLANTIC. OVERALL HIGH TEMPS SHOULD RANGE IN THE MID/UPPER 50S WEDNESDAY AND THURSDAY...BEFORE SOUTHERLY FLOW RETURNS TO THE AREA ALONG THE WESTERN EDGE OF HIGH PRESSURE ON FRIDAY. TEMPS SHOULD PEAK INTO THE LOW/MID 60S BY LATE WEEK. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
VFR THROUGH 12Z. AS RAIN OVERSPREADS THE AREA...THE POTENTIAL FOR AT LEAST MVFR CEILINGS WILL INCREASE AFTER 06Z-09Z...BUT GIVEN LOW-LEVEL DRY AIR IN PLACE OPTED TO DELAY FLIGHT RESTRICTIONS UNTIL AFTER 12Z. ONCE CEILINGS LOWER SATURDAY MORNING...MVFR CEILINGS SHOULD PREVAIL FOR THE BALANCE OF THE 18Z TAF PERIOD...AND AT LEAST OCCASIONAL IFR CEILINGS/MVFR VISIBILITIES CANNOT BE RULED OUT. EXTENDED AVIATION OUTLOOK...PERIODS OF MVFR OR LOWER CONDITIONS APPEAR LIKELY WITH RAIN/SHOWERS SATURDAY THROUGH TUESDAY WHILE A WEDGE OF HIGH PRESSURE PERSISTS INLAND AND SEVERAL AREAS OF LOW PRESSURE SHIFT ALONG THE SOUTHEAST COAST.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
A WEAK PRESSURE PATTERN WILL MAINTAIN N/NE WINDS AND SEAS AROUND 1 FOOT THIS AFTERNOON THROUGH THIS EVENING. THEN...A TIGHTENING PRESSURE GRADIENT SHOULD TRANSLATE TO NE WINDS INCREASING TO 10-15 KT OVERNIGHT...ACCOMPANIED BY SEAS BUILDING TO 2-3 FT. SATURDAY THROUGH WEDNESDAY...WINDS AND SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT ADVISORY LEVELS THIS WEEKEND AS A WEDGE OF HIGH PRESSURE STRENGTHENS INLAND AND A LOW PRESSURE SYSTEM SHIFTS FROM THE NORTHEAST GULF OF MEXICO ALONG THE SOUTHEAST COAST. PERIODS OF RAIN/SHOWERS WILL CONTINUE OVER THE WATERS INTO EARLY NEXT WEEK UNTIL A COLD FRONT SHIFTS OFFSHORE WEDNESDAY. STRONG WINDS WILL ACCOMPANY THE FRONT AS IT SHIFTS OFFSHORE EARLY WEDNESDAY...WITH AT LEAST SMALL CRAFT ADVISORY CONDITIONS EXPECTED FOR ALL WATERS. A GALE WATCH COULD BE EVENTUALLY NEEDED FOR A PORTION OF THE WATERS ON WEDNESDAY MORNING AND AFTERNOON AS WINDS GUST TO 30-35 KT. SEAS WILL ALSO BUILD UPWARDS TO 6-8 FT WEDNESDAY AFTERNOON BEFORE SLOWLY IMPROVING WEDNESDAY NIGHT.
-- End Changed Discussion --
&& .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && $$ NEAR TERM...SPR SHORT TERM...DPB LONG TERM...DPB AVIATION...SPR MARINE...DPB/SPR

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.