Area Forecast Discussion
Issued by NWS Charleston, SC

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000
FXUS62 KCHS 111506
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
1006 AM EST THU FEB 11 2016

.SYNOPSIS...
HIGH PRESSURE TODAY WILL GIVE WAY TO A WEAK AREA OF LOW PRESSURE
AND ASSOCIATED COLD FRONT TONIGHT. THIS LOW WILL PULL AWAY FROM THE
REGION ON FRIDAY AND AN ARCTIC COLD FRONT WILL PUSH THROUGH ON
SATURDAY. HIGH PRESSURE WILL THEN REMAIN IN CONTROL UNTIL EARLY
NEXT WEEK WHEN THE NEXT FRONTAL SYSTEM WILL IMPACT THE REGION.
MORE HIGH PRESSURE WILL RETURN THEREAFTER.

&&

.NEAR TERM /THROUGH TONIGHT/...
TODAY...NO SIGNIFICANT CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. HIGH PRESSURE WILL PREVAIL WITH GENERALLY CLEAR SKIES FOR
MOST OF THE DAY WITH A FEW CLOUDS LATE. LOW-LEVEL THICKNESS PROGS
SUGGEST HIGHS WILL RANGE FROM AROUND 50 NEAR THE SANTEE RIVER TO
AROUND 60 NEAR THE ALTAMAHA RIVER. LIGHT WEST WINDS EARLY WILL
SHIFT MORE SOUTH TO SOUTHWEST THIS AFTERNOON.

TONIGHT A CHANNELED VORT WILL DROP INTO THE CAROLINAS AND SPUR A
SERIES OF WEAK SURFACE WAVES THAT WILL TRAVERSE A POORLY DEFINED
BAROCLINIC REGION ACROSS THE SE STATES. MOISTURE WILL INCREASE
BELOW 10K FT RESULTING IN AN EXPANSION OF CLOUDINESS OVER THE
REGION OVERNIGHT BUT WITH 00Z MODELS PAINTING HIGH 850 MB TO 500
MB CONDENSATION PRES DEFICITS...WE MAINTAINED A DRY FORECAST
TONIGHT ALTHOUGH A FEW BRIEF SPRINKLES LATE CANNOT BE RULED OUT.
THE INCREASE IN CLOUDS AND LOW LEVEL DEW POINTS SHOULD SPELL OUT A
MILDER OVERNIGHT...TEMPS THIS EVENING MAY BE TRICKY DEPENDING ON
WHAT TIME CLOUDS INCREASE. WE GRADUATED LOWS FROM THE MID 30S N TO
THE LOWER 40S S.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
FRIDAY AND FRIDAY NIGHT...THE FORECAST AREA WILL REMAIN WELL WITHIN
THE COLD TROUGH ALOFT. THE MORNING WILL START OFF WITH A WEAK AREA
OF LOW PRESSURE SITUATED JUST OFF THE COAST AND POISED TO PULL AWAY
FROM THE AREA INTO THE AFTERNOON. THE FIRST HALF OF THE DAY WILL
BRING MOSTLY CLOUDY SKIES BEFORE CLEARING OUT IN THE AFTERNOON AS
DRIER AIR MOVES IN QUICKLY BEHIND THE DEPARTING SYSTEM. MODELS ARE
IN PRETTY GOOD AGREEMENT THAT ALMOST ALL OF THE PRECIPITATION
ASSOCIATED WITH THE SYSTEM WILL STAY JUST OFFSHORE...THOUGH THERE IS
SOME VERY LIGHT QPF IN THE MORNING. THE FORECAST MAINTAINS THE FEW
HOURS OF SLIGHT CHANCE POP ACROSS EASTERN BERKELEY AND CHARLESTON
COUNTIES...BUT LITTLE TO NO MEASURABLE RAINFALL IS EXPECTED.
TEMPERATURES WILL DEPEND GREATLY ON HOW QUICKLY CLOUDS ERODE AND
INSOLATION CAN BEGIN. CLOUDS WILL LIKELY HANG ON IN THE EAST THE
LONGEST SO WE MAY END UP WITH QUITE A TEMPERATURE GRADIENT. THE
FORECAST FEATURES HIGHS FROM THE MID 60S ALONG THE ALTAMAHA TO THE
LOW TO MID 50S FOR THE FAR EASTERN ZONES. OVERNIGHT...HIGH PRESSURE
WILL BEGIN TO BUILD IN AND COLD NORTHWEST FLOW WILL PREVAIL. LOWS
WILL DIP INTO THE MID TO UPPER 30S INLAND...WITH LOW 40S AT THE
COAST.

SATURDAY THROUGH SUNDAY...THE WEEKEND WILL BE DEFINED BY A STRONG
ARCTIC COLD FRONT POISED TO CROSS THE REGION FROM THE
NORTH/NORTHWEST LATE SATURDAY AND SATURDAY NIGHT. THE RESULT WILL BE
A VERY COLD WEEKEND. AHEAD OF THE FRONT...SATURDAY HIGHS WILL RANGE
FROM AROUND 50 TO THE LOW/MID 50S ACROSS SOUTHEAST GEORGIA. SATURDAY
NIGHT WILL BE A COLD AND BLUSTERY NIGHT WITH LOWS DIPPING INTO THE
LOW 20S IN MANY AREAS...WITH MID TO UPPER 20S COMMON. WITH ELEVATED
WINDS SUNDAY MORNING...WIND CHILL VALUES WILL FALL INTO AT LEAST THE
LOW TO MID TEENS NORTH OF I-16 WITH UPPER TEENS TO LOW 20S FURTHER
SOUTH. A WIND CHILL ADVISORY MAY BE NEEDED AND WE WILL MAINTAIN THE
MENTION IN THE HAZARDOUS WEATHER OUTLOOK. FINALLY FOR SUNDAY...HIGHS
WILL BE 20 DEGREES OR MORE BELOW NORMAL. TEMPERATURES WILL STRUGGLE
TO REACH 40 AROUND THE CHARLESTON AREA...WITH MID 40S AROUND
SAVANNAH AND POINTS SOUTH.

LAKE WINDS...ANOTHER ROUND OF STRONG WINDS WILL BE POSSIBLE OVER
LAKE MOULTRIE LATE SATURDAY INTO SUNDAY. A LAKE WIND ADVISORY COULD
EVENTUALLY BE NEEDED.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
MODEL AGREEMENT REMAINS GOOD REGARDING THE MAIN FORECAST IN THE LONG
TERM WHICH IS SYSTEM EXPECTED TO PUSH THROUGH LATE MONDAY THROUGH
EARLY TUESDAY. THE PERIOD WILL START OFF WITH HIGH PRESSURE OVER NEW
ENGLAND AND A STRENGTHENING WEDGE INLAND AND A SHARPENING COASTAL
TROUGH OFFSHORE. LOW PRESSURE IS PROGGED TO MOVE INLAND THROUGH
CENTRAL GEORGIA AND THE CAROLINAS MONDAY NIGHT. THE BEST TIME PERIOD
FOR RAINFALL LOOKS TO BE DURING THIS TIME AS THE DEEP MOISTURE
ASSOCIATED WITH THE SYSTEM DOES NOT PRECEDE IT BY MUCH. MODEL
AGREEMENT IS GOOD ENOUGH TO GO WITH LIKELY POPS...THOUGH IT
SHOULDN/T BE A LONG DURATION EVEN THANKS TO THE PROGRESSIVE NATURE
OF THE MID/UPPER LEVEL TROUGH. BEHIND THIS SYSTEM...DRY HIGH PRESSURE
WILL RETURN. TEMPERATURES LOOK AS THOUGH THEY WILL MODERATE THROUGH
THE PERIOD...STARTING OFF BELOW NORMAL MONDAY WITHIN THE
WEDGE...THEN INCREASING THEREAFTER TO NEAR NORMAL BY MID WEEK.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
VFR AT KCHS/KSAV THROUGH 06Z FRIDAY. SMALL CHANCES FOR MVFR CIGS
AT BOTH TERMINALS IN THE 08Z-12Z TIME FRAME TONIGHT AS FORECAST
SOUNDINGS INDICATE A LOWERING STRATOCUMULUS POTENTIAL IN A WARM
AIR ADVECTION REGIME.

EXTENDED AVIATION OUTLOOK...A BRIEF PERIOD OF MVFR/IFR CEILINGS
IS POSSIBLE FRIDAY AS A COLD FRONT MOVES THROUGH.

&&

.MARINE...
THIS MORNING...OFFSHORE FLOW WILL CONTINUE TO DIMINISH AS A
SURFACE RIDGE BUILDS OVER THE WATERS RELAXING THE PRES GRADIENTS.
W FLOW WILL FALL BELOW 10 KT LATER THIS MORNING THEN THE FLOW
SHOULD BECOME LIGHT AND VARIABLE BY THIS EVENING. SEAS WILL FALL
TO 2 FT OR LESS OVER THE NEAR SHORE WATERS DURING THE AFTERNOON.

WEAK LOW PRES WILL SHIFT INTO THE WATERS BY DAWN ON FRIDAY...THE
FLOW SHOULD REMAIN MOSTLY LIGHT AND CHAOTIC AS THIS FEATURE
APPROACHES OVERNIGHT. WARM AIR ADVECTION WILL RE-ESTABLISH A
STRONGER LOW LEVEL INVERSION TONIGHT BUT AN INCREASING SW JET
OVER WARMER OUTER GEORGIA WATERS CLOSER TO THE GULF STREAM SHOULD
INCITE AN UPTICK IN SW FLOW BEYOND 40 NM OFFSHORE BUT WINDS AND
SEAS LIKELY WILL REMAIN BELOW SMALL CRAFT ADVISORY LEVELS.

FRIDAY THROUGH MONDAY...A WEAK AREA OF LOW PRESSURE WILL PULL AWAY
FROM THE LOCAL WATERS ON FRIDAY AND COULD LEAD TO A SHORT PERIOD OF
NEAR SMALL CRAFT ADVISORY WINDS ACROSS THE OUTER GEORGIA WATERS.
BEHIND THIS SYSTEM...A STRONG ARCTIC COLD FRONT WILL PUSH THROUGH
SATURDAY NIGHT AND HIGH PRESSURE TO THE NORTH WILL RESULT IN A
PERSISTENT NORTHEAST FLOW THROUGH THE REMAINDER OF THE WEEKEND. THE
SURGE BEHIND THE FRONT SATURDAY NIGHT WILL RESULT IN SOLID SMALL
CRAFT ADVISORY CONDITIONS ACROSS ALL WATERS WHICH WILL CONTINUE
THROUGH AT LEAST SUNDAY MORNING. OTHERWISE...CONDITIONS SHOULD
IMPROVE INTO MONDAY WHEN A COASTAL TROUGH WILL DEVELOP AND
EVENTUALLY LIFT NORTHWARD AHEAD OF AN APPROACHING LOW PRESSURE
SYSTEM.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...BSH
LONG TERM...BSH
AVIATION...
MARINE...BSH


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