Area Forecast Discussion
Issued by NWS Charleston, SC

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372
FXUS62 KCHS 110223
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
923 PM EST WED FEB 10 2016

.SYNOPSIS...
HIGH PRESSURE WILL BUILD EAST FROM THE LOWER GULF COAST REGION
THROUGH TONIGHT. HIGH PRESSURE ON THURSDAY WILL GIVE WAY TO A
WEAK AREA OF LOW PRESSURE AND ASSOCIATED COLD FRONT THURSDAY
NIGHT. BEHIND THIS SYSTEM AN ARCTIC COLD FRONT WILL PUSH THROUGH
THE REGION ON SATURDAY. HIGH PRESSURE WILL THEN REMAIN IN CONTROL
UNTIL EARLY NEXT WEEK WHEN THE NEXT FRONTAL SYSTEM WILL IMPACT THE
REGION.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
HIGH PRESSURE CENTERED OVER THE NORTHERN GULF OF MEXICO WILL
PROPAGATE EAST OVERNIGHT...REACHING CENTRAL FLORIDA BY SUNRISE. A
NORTHWARD EXTENSION OF THE SURFACE HIGH WILL MOVE INTO THE AREA
OVERNIGHT...ALTHOUGH FULL DECOUPLING OF THE BOUNDARY LAYER IS
UNLIKELY GIVEN A CONTINUATION OF WEAK COLD AIR ADVECTION.

CLOUD COVER ASSOCIATED WITH WEAK SHORTWAVE ENERGY CROSSING THE
SOUTHERN APPALACHIANS IS RAPIDLY APPROACHING THE INTERIOR
SOUTHEAST GEORGIA ZONES LATE THIS EVENING. IT NOW APPEARS THAT AT
LEAST A FEW HOURS OF MOSTLY CLOUDY SKIES WILL IMPACT MAINLY INLAND
AREAS AS WELL AS THE CHARLESTON METRO AREA BEFORE CLOUDS BEGIN TO
MIX OUT IN THE LEE OF THE BLUE RIDGE. STILL EXPECT CLEAR SKIES TO
PREVAIL AFTER 2-3 AM FOR THE ENTIRE AREA AND SKY COVER GRIDS HAVE
BEEN UPDATED TO REFLECT THIS THINKING.

IT WILL STILL BE A CHILLY NIGHT FOR THE REGION WITH LOW DROPPING
INTO THE MID-UPPER 20S WITH LOWER 30S AT THE BEACHES...ALTHOUGH A
SLIGHT MODIFICATION IS NEEDED TO HOURLY TEMPERATURES ACROSS
MAINLY INLAND AREAS TO ACCOUNT FOR LIKELY INSOLATION EFFECTS FROM
THE APPROACHING CLOUD COVER. STILL ANTICIPATE SKIES WILL CLEAR
ENOUGH A FEW HOURS PRIOR TO SUNRISE TO REACH FORECAST MINIMUMS.
WIND CHILLS WILL BOTTOM OUT IN THE UPPER TEENS TO LOWER 20S.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
ON THURSDAY THE UPPER LONGWAVE FLATTENS OUT WITH LOW-LEVEL
THICKNESSES INCREASING ACROSS THE DEEP SOUTH. A WEAK SURFACE
FRONT WILL DROP TOWARD THE AREA IN THE AFTERNOON...BRINGING A
SLIGHT INCREASE IN STRATOCUMULUS LATE IN THE DAY. OTHERWISE MOST
AREAS WILL SEE PARTLY TO MOSTLY SUNNY SKIES DURING THE DAY WITH
REBOUNDING TEMPS IN THE LOW/MID 50S.

THURSDAY NIGHT A CHANNELED VORT WILL DROP INTO THE CAROLINAS AND
SPUR A WEAK SURFACE WAVE TO DEVELOP OFF THE SC COAST ALONG THE
TRAVERSING FRONT. SIGNIFICANTLY INCREASING SKY COVER OVER
SOUTHEAST GA WILL KEEP LOW TEMPS IN THE LOWER 40S THOUGH COLD
ADVECTION IN NORTHERN AREAS WILL DROP TEMPS INTO THE MIDDLE 30S.
THE ONLY APPRECIABLE RAIN CHANCES WILL BE OVER THE COASTAL WATERS
AND FAR EASTERN LAND AREAS WHERE THERE MAY BE ENOUGH MOISTURE AND
LIFT ALONG THE FRONT TO PRODUCE PATCHY LIGHT RAIN.

THE FRONT WILL DISSIPATE OVER THE AREA ON FRIDAY WHILE A
RELATIVELY ZONAL FLOW PERSISTS ALOFT. MOSTLY CLOUDY SKIES WILL
START THE DAY BUT WE EXPECT DECREASING CLOUDINESS DURING THE
AFTERNOON. SLIGHT WARM ADVECTION OVER SOUTHEAST GA AND SOME LATE
AFTERNOON SUN SHOULD PRODUCE HIGH TEMPS IN THE LOW TO MID 60S.
ELSEWHERE THE HIGHS WILL BE IN THE LOW TO MID 50S.

AN EXPANSIVE 1044 MB HIGH WILL BUILD FROM CANADA INTO THE NORTHERN
PLAINS SATURDAY MORNING...PUSHING AN ARCTIC COLD FRONT THROUGH THE
LOCAL FORECAST AREA. AFTERNOON COLD AIR ADVECTION WILL KEEP
SATURDAY HIGH TEMPS IN THE UPPER 40S NORTH TO MIDDLE 50S SOUTH.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MODEL AGREEMENT IN THE LONG TERM PERIOD IS REASONABLY GOOD AND
THE FORECAST IS PRETTY QUIET UNTIL LATE IN THE PERIOD. THINGS
START OFF SATURDAY NIGHT WITH SOME OF THE COLDEST AIR OF THE
SEASON BEHIND THE ARCTIC COLD FRONT. LOWS WILL DIP INTO THE LOW TO
MID 20S...AND ELEVATED OVERNIGHT WINDS WILL RESULT IN WIND CHILLS
FALLING INTO THE LOW TO MID TEENS FOR MUCH OF THE AREA SUNDAY
MORNING. INCLUDED MENTION OF POSSIBLE WIND CHILL ADVISORY IN THE
HAZARDOUS WEATHER OUTLOOK.

THEREAFTER...HIGH PRESSURE WILL BE THE PRIMARY WEATHER FEATURE
ACROSS THE REGION THROUGH THE REMAINDER OF THE WEEKEND. THE NEXT
LOW PRESSURE SYSTEM AND NOTEWORTHY RAINFALL CHANCES WILL IMPACT
THE AREA EARLY NEXT WEEK AS A SHORTWAVE APPROACHES FROM THE WEST
AND PUSHES A DEVELOPING SYSTEM THROUGH THE SOUTHERN APPALACHIANS
LATE MONDAY. TEMPERATURES LOOK TO BE WELL BELOW NORMAL ON
SUNDAY...WITH A MODERATING TREND TO NEAR NORMAL THROUGH EARLY NEXT
WEEK.

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.

&&

.AVIATION /02Z THURSDAY THROUGH MONDAY/...
VFR.

EXTENDED AVIATION OUTLOOK...A BRIEF PERIOD OF MVFR CEILINGS IS
POSSIBLE FRIDAY AFTERNOON AND EVENING AS A COLD FRONT MOVES
THROUGH.

&&

.MARINE...
TONIGHT...GUSTY WEST WINDS WILL WEAKEN SLIGHTLY THROUGH THE NIGHT
AS A NORTHWARD EXTENSION OF SURFACE HIGH PRESSURE MOVES IN FROM
THE WEST. THE COMBINATION OF GUSTY CONDITIONS AND ELEVATED SEAS
WILL NECESSITATE KEEPING SMALL CRAFT ADVISORIES IN PLACE THROUGH
MUCH OF THE NIGHT FOR ALL MARINE LEGS WITH THE EXCEPTION OF
CHARLESTON HARBOR.

THURSDAY THROUGH SUNDAY...RELATIVELY QUIET CONDITIONS WILL OCCUR
THURSDAY AND THURSDAY NIGHT. A WEAK COASTAL LOW PRESSURE SYSTEM
MOVING NORTHEAST ALONG THE COASTLINE FRIDAY MAY PRODUCE A BRIEF
PERIOD OF SMALL CRAFT ADVISORY WINDS AND/OR SEAS OVER THE OFFSHORE
GA WATERS. OTHERWISE THE NEXT MAIN SURGE WILL BE LATE SATURDAY
INTO SUNDAY MORNING BEHIND AN ARCTIC COLD FRONT. WINDS/SEAS WILL
INCREASE DRASTICALLY BEHIND THE FRONT AND SMALL CRAFT ADVISORIES
WILL UNDOUBTEDLY BE NECESSARY FOR PORTIONS OF THE WATERS.

&&

.TIDES/COASTAL FLOODING...
OFFSHORE WINDS WILL PRODUCE LOW OUT TIDES AROUND LOW TIDE EARLY
THURSDAY REACHING NEAR -1.0 FT MLLW IN CHARLESTON HARBOR AND -1.5
FT MLLW AT FORT PULASKI.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 AM EST THURSDAY FOR AMZ350-352-
     354-374.

&&

$$

ST



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