Area Forecast Discussion
Issued by NWS Charleston, SC

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000
FXUS62 KCHS 130244
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
944 PM EST FRI FEB 12 2016

.SYNOPSIS...
A COLD FRONT WILL MOVE OFFSHORE EARLY THIS EVENING...FOLLOWED BY
AN ARCTIC COLD FRONT SATURDAY MORNING. HIGH PRESSURE WILL THEN
REMAIN IN CONTROL EARLY NEXT WEEK BEFORE A LOW PRESSURE SYSTEM
IMPACTS THE REGION LATE MONDAY INTO TUESDAY. HIGH PRESSURE WILL
THEN RETURN AND PERSIST MID TO LATE NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
13/02Z SURFACE ANALYSIS PLACED 1009 HPA LOW PRESSURE ABOUT 200 NM
EAST OF CAPE HATTERAS WITH A COLD FRONT EXTENDING SOUTHWEST INTO
FAR SOUTHERN SOUTH CAROLINA WHERE IT BECOMES QUASI-STATIONARY.
THIS FRONT WILL MOVE VERY LITTLE OVER THE NEXT FEW HOURS BEFORE
BECOMING ABSORBED IN THE RAPIDLY APPROACHING ARCTIC COLD FRONT
WHICH IS CURRENTLY MOVING ACROSS THE FAR WESTERN SOUTH CAROLINA
MIDLANDS AND CENTRAL GEORGIA.

LIGHT WINDS THIS EVENING WILL BECOME NORTHWEST 10-15 MPH WITH
GUSTS TO 20 MPH EARLY SATURDAY MORNING AS THE ARCTIC COLD PUSHES
OFFSHORE AND A STRONG POST-FRONTAL ISALLOBARIC RESPONSE ENSUES.
ALREADY SEEING PRESSURE RISES OF +3-5 HPA/HR OVER SOUTHERN
TENNESSEE...NORTHERN GEORGIA AND NORTHERN ALABAMA...WHICH WILL
TRANSLATE EAST WITH TIME AS COLD AIR ADVECTION INTENSIFIES ALOFT.
SKIES WILL REMAIN CLEAR THROUGH THE NIGHT WITH LOWS RANGING FROM
THE LOWER 30S ACROSS PORTIONS OF DORCHESTER AND BERKELEY COUNTIES
TO THE LOWER 40S ALONG THE GEORGIA COAST AS WELL AS INTERIOR
PORTIONS OF LIBERTY...LONG AND MCINTOSH COUNTIES. WIND CHILLS WILL
DROP INTO THE MID 20S NORTH TO THE MID 30S SOUTH.

SOME GROUND FOG APPEARS TO HAVE DEVELOPED WITHIN THE STATIONARY
FRONTAL ZONAL THIS EVENING WHERE WINDS HAVE GONE CALM. VSBYS AT
KNBC AND KARW HAVE BEEN WAVERING BETWEEN 1/2 AND 2 MILES OVER THE
PAST HOUR OR SO...BUT THE FOG SEEMS TO FAIRLY SHALLOW AS THERE HAS
YET TO BE ANY INDICATIONS OF IT IN GOES-EAST FOG PRODUCTS. THIS
WILL BE MONITORED CAREFULLY...BUT THE RISK FOG WILL QUICKLY END
OVER THE NEXT FEW HOURS AS THE ARCTIC COLD FRONT PUSHES OFFSHORE
AND WINDS INCREASE.

FOR THE LATE EVENING UPDATE...
* LOWERED OVERNIGHT LOWS 1-2 DEGREES FOR MOST AREAS PER GOING
  SHORT TERM MODEL TRENDS.
* ADJUSTED NEAR TERM WIND GRIDS TO BETTER HANDLE THE EVOLUTION OF
  THE STATIONARY FRONT OVER FAR SOUTHERN SOUTH CAROLINA FOR THE
  NEXT FEW HOURS.
* ADJUSTED HOURLY TEMPERATURES AND DEWPOINTS TO REFLECT GOING
  OBSERVATIONS AND SHORT TERM MODEL TRENDS.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
SATURDAY...DRY WEATHER IS EXPECTED AS AN ARCTIC COLD FRONT MOVES
THROUGH THE REGION IN THE MORNING. STRONG SURFACE HIGH PRESSURE
MOVING INTO THE MIDDLE MISSISSIPPI VALLEY WILL USHER IN MUCH
COLDER AIR OVER THE SOUTHEASTERN UNITED STATES. DESPITE PLENTIFUL
SUNSHINE...NORTHWEST FLOW AND STRONG COLD AIR ADVECTION WILL
DOMINATE. TEMPERATURES WILL STRUGGLE TO REACH THE MID/UPPER 40S
(ACROSS THE TRI-COUNTY) AND THE LOWERS 50S (ACROSS THE SAVANNAH
METRO AREA). TEMPERATURES WILL PLUMMET SATURDAY NIGHT THE HIGH
MOVES OVER THE OHIO VALLEY AND COLD AIR ADVECTION CONTINUES DUE TO
NORTHERLY SURFACE WINDS AND NORTHWEST FLOW ALOFT. ADDITIONALLY,
LITTLE TO NO CLOUD COVER WILL ASSIST IN THE COOLING. TEMPERATURES
WILL FALL INTO THE LOW/MID 20S ACROSS MOST OF THE AREA. THE
EXCEPTION WILL BE THE BEACHES. THE SOUTH CAROLINA BEACHES WILL BE
NEAR 30 DEGREES WHILE THE GEORGIA BEACHES WILL BE IN THE MID 30S.
WINDS WILL BE 5-10 MPH. THIS WILL EQUATE TO WIND CHILL VALUES IN
THE MID TO UPPER TEENS ACROSS MOST OF OUR SOUTH CAROLINA COUNTIES
AND THE LOWER TO MID 20S ACROSS MOST OF OUR GEORGIA COUNTIES. THIS
IS AN INCREASE FROM THE PREVIOUS FORECAST FOR THE GEORGIA COUNTIES
BECAUSE MODELS TRENDED SLIGHTLY "WARMER" WITH THE MINIMUM
TEMPERATURES AND SLIGHTLY LOWER WITH THE WINDS. A WIND CHILL
ADVISORY COULD BE NEEDED LATE SATURDAY NIGHT INTO SUNDAY
MORNING...THE MOST LIKELY PLACES BEING THE SOUTH CAROLINA COASTAL
ZONES.

SUNDAY...ANOTHER DRY AND COLD DAY IS EXPECTED AS THE SURFACE HIGH
SHIFTS TO THE MID-ATLANTIC STATES. COLD AIR ACROSS THE REGION
ALONG WITH NORTHEAST WINDS WILL ALLOW TEMPERATURES TO BARELY REACH
THE LOWER 40S (ACROSS THE TRI-COUNTY) AND THE MID 40S (ACROSS THE
SAVANNAH METRO AREA). OUR SOUTHERNMOST GEORGIA COUNTIES MIGHT
REACH 50 DEGREES. THE PATTERN BEGINS TO CHANGE SUNDAY NIGHT AS THE
HIGH SHIFTS OFF OF THE NORTHEAST U.S. COAST. TEMPERATURES WILL BE
SEVERAL DEGREES WARMER DUE TO MORE OF AN ONSHORE WIND. IN
GENERAL...LOW TEMPERATURES SHOULD BE IN THE 30S...COLDEST FAR
INLAND.

MONDAY...THE DAY WILL START OFF CHILLY AND THERE IS SOME CONCERN
REGARDING FROZEN PRECIPITATION BEFORE DAYBREAK. MODELS SHOW
PRECIPITATION DEVELOPING ALONG THE COAST NEAR THIS TIME.
HOWEVER...TEMPERATURES SHOULD BE IN THE UPPER 30S ALONG THE SOUTH
CAROLINA COAST AND THE LOWER 40S ALONG THE GEORGIA COAST.
TEMPERATURES ARE EXPECTED TO WARM QUICKLY AS A SOUTHERLY FLOW
STRENGTHENS WELL AHEAD OF LOW PRESSURE TRACKING OVER THE
MISSISSIPPI RIVER VALLEY. FOR NOW...KEPT RAIN SHOWERS IN THE
MORNING FORECAST. THOUGH...THE TEMPERATURES AND PRECIPITATION
WILL NEED TO BE MONITORED CLOSELY. POPS INCREASE IN THE
AFTERNOON...MAINLY ASSOCIATED WITH A COASTAL TROUGH THAT SKIRTS
THE COAST. AFTERNOON HIGHS SHOULD BE IN THE 60S.

LAKE WINDS...STRONG WINDS ARE POSSIBLE OVER LAKE MOULTRIE
SATURDAY NIGHT INTO SUNDAY. A LAKE WIND ADVISORY MAY BE NEEDED.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
A STRENGTHENING LOW PRESSURE WILL TRACK OVER THE DEEP SOUTH AND THEN
SOUTHEAST STATES MONDAY NIGHT INTO TUESDAY...LEADING TO RAIN/SHOWERS
OVER MUCH OF THE AREA. INSTABILITY WILL REMAIN LOW DURING THIS
PERIOD...THUS THUNDER REMAINS OUT OF THE FORECAST. HOWEVER...A 50 TO
60 KT LOW LVL JET WILL ACCOMPANY THE SYSTEM...LIKELY LEADING TO
GUSTY WIND CONDITIONS MONDAY NIGHT AND TUESDAY. RAIN/SHOWERS ARE
EXPECTED TO QUICKLY SHIFT OFFSHORE BY TUESDAY AFTERNOON AS DRY HIGH
PRESSURE BUILDS OVER THE REGION BEHIND THE DEPARTING LOW. HIGH
PRESSURE IS THEN EXPECTED TO PERSIST THROUGH MUCH OF THE WEEK.
OVERALL HIGH TEMPS SHOULD RANGE IN THE UPPER 50S TO AROUND 60 ON
TUESDAY...THEN GRADUALLY WARM INTO THE LOW/MID 60S BY THE WEEKEND.
OVERNIGHT LOWS WILL BE NOTICEABLY WARMER THAN PREVIOUS DAYS...IN THE
LOW/MID 40S.

&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
VFR. GUSTY WINDS WILL DEVELOP DURING THE DAY SATURDAY BEHIND AN
ARCTIC COLD FRONT.

EXTENDED AVIATION OUTLOOK...FLIGHT RESTRICTIONS ARE LIKELY MONDAY
NIGHT INTO TUESDAY DUE TO A LOW PRESSURE SYSTEM BRINGING RAIN TO
THE AREA. GUSTY WINDS ARE ALSO EXPECTED MONDAY NIGHT INTO
TUESDAY.

&&

.MARINE...
TONIGHT..LOW PRESSURE OFF THE OUTER BANKS WILL CONTINUE TO LIFT
NORTHEAST TONIGHT BEFORE AN ARCTIC COLD FRONT DROPS THROUGH THE
WATERS EARLY SATURDAY. INCREASING N WINDS BEHIND THE FRONT WILL
BRING COLDER AIR OVER THE WATERS...ENHANCING MIXING PROFILES OVER
THE WARMER OFFSHORE WATERS. A SMALL CRAFT ADVISORY REMAINS IN
EFFECT FOR THE CHARLESTON COUNTY AND OFFSHORE GEORGIA WATERS FOR
THE EXPECTED DEVELOPMENT OF GUSTY WINDS TO 25 KT. SEAS WILL
AVERAGE 2-3 FT NEARSHORE WATERS AND 3-5 FT OFFSHORE WATERS.

SATURDAY THROUGH TUESDAY...AN ARCTIC COLD FRONT WILL SHIFT OFFSHORE
EARLY SATURDAY WITH STRONG COLD AIR ADVECTION OVER COASTAL WATERS.
WINDS WILL TURN TO THE NORTH AND THEN NORTHEAST BEHIND A SECONDARY
SURGE SATURDAY NIGHT. CONDITIONS SHOULD BRIEFLY IMPROVE MONDAY AS
A COASTAL TROUGH DEVELOPS OFF THE SOUTHEAST COAST...BUT WILL
QUICKLY DETERIORATE LATE MONDAY NIGHT INTO TUESDAY AS A
STRENGTHENING LOW PRESSURE SYSTEM TRACKS OVER THE DEEP SOUTH AND
THEN OFF THE MID ATLANTIC AND SOUTHEAST COAST. STRONG LOW LVL
WINDS ASSOCIATED WITH THE SYSTEM WILL LIKELY RESULT IN SMALL CRAFT
ADVISORIES FOR ALL WATERS AND POTENTIALLY GALE CONDITIONS OVER
WARMER WATERS OFFSHORE.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 11 AM EST SATURDAY FOR AMZ374.
     SMALL CRAFT ADVISORY FROM 4 AM TO 11 AM EST SATURDAY FOR
     AMZ350.

&&

$$

ST


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