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000
FXUS62 KCHS 091932
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
332 PM EDT SUN MAR 9 2014

.SYNOPSIS...
THE REGION WILL REMAIN BETWEEN A TROUGH OF LOW PRESSURE TO THE
NORTH AND HIGH PRESSURE TO THE SOUTH. WEAKENING LOW PRESSURE WILL
TRACK FROM THE GULF OF MEXICO OFF THE SOUTHEAST COAST TUESDAY
NIGHT AND WEDNESDAY. A STRONG COLD FRONT WILL MOVE THROUGH THE
AREA WEDNESDAY NIGHT...FOLLOWED BY COOL HIGH PRESSURE INTO NEXT
WEEKEND. ANOTHER COLD FRONT COULD PUSH THROUGH THE REGION LATE
NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
A LEE-SIDE SURFACE TROUGH WILL STRETCH FROM THE MID ATLANTIC
STATES THROUGH THE CAROLINAS TONIGHT...WHILE HIGH PRESSURE
LINGERS TO THE SOUTH. THE REMNANTS OF A WEAKENING FRONT WILL
CONTINUE TO SLIP INTO THE FORECAST AREA AND DISSIPATE AS IT
BECOMES PARALLEL TO FLOW ALOFT. ELONGATED SHORTWAVE ENERGY WILL
ALSO DESCEND INTO THE SOUTHEAST STATES OVERNIGHT...WEAKENING AS IT
RUNS INTO FLAT UPPER RIDGING FROM THE BAHAMAS. AS A
RESULT...EXPECT LITTLE SENSIBLE WEATHER IMPACTS THROUGH THE NEAR
TERM PERIOD. DEEP WEST FLOW WILL MAINTAIN DRY AND MOSTLY CLEAR
CONDITIONS. LOW TEMPERATURES WILL RANGE FROM THE MID TO UPPER 40S
AWAY FROM THE WARMER COASTLINE.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MONDAY THROUGH TUESDAY...DOWNSLOPE/OFFSHORE LOW LEVEL FLOW
BETWEEN A LEE SIDE TROUGH CENTERED NORTH OF THE REGION AND SURFACE
HIGH PRESSURE TO THE SOUTH WILL SUPPORT ABOVE NORMAL TEMPERATURES.
EXPECT HIGHS IN THE MID TO UPPER 70S MONDAY...AND UPPER 70S TO
AROUND 80F AS A ZONAL FLOW ALOFT GIVES WAY TO SUBTLY BUILDING
HEIGHTS TUESDAY. AT THE BEACHES...THE SEA BREEZE WILL USHER MUCH
COOLER TEMPERATURES ONSHORE EACH AFTERNOON. NO PRECIPITATION IS
EXPECTED THROUGH THIS PERIOD.

TUESDAY NIGHT THROUGH WEDNESDAY...THE PATTERN WILL BECOME MORE
ACTIVE. IN RESPONSE TO A DIGGING NORTHERN STREAM UPPER TROUGH...A
SOUTHERN STREAM LOW WILL EJECT EASTWARD ACROSS THE NORTHERN GULF OF
MEXICO TUESDAY NIGHT INTO WEDNESDAY...WEAKENING WITH TIME. 09/12Z
GUIDANCE CONTINUES TO DEPICT SUFFICIENT  DEEP LAYER MOISTURE PUSHING
THROUGH THE REGION TO JUSTIFY CHANCE POPS TUESDAY NIGHT/EARLY
WEDNESDAY. MEANWHILE...THE AMPLIFYING NORTHERN STREAM TROUGH WILL
CONTINUE TO DIVE E/SE OUT OF THE UPPER MIDWEST...SUPPORTING AN
INTENSIFYING SURFACE LOW PRESSURE WHICH WILL TRACK ACROSS THE MID
MISSISSIPPI VALLEY INTO THE CENTRAL APPALACHIANS LATE TUESDAY NIGHT
INTO WEDNESDAY. THIS DEEPENING SYSTEM WILL PUSH A STRONG COLD FRONT
TOWARD THE FORECAST AREA WEDNESDAY. A BREAK COULD DEVELOP IN
PRECIPITATION PRODUCED BY THE INITIAL SHORTWAVE AND PRECIPITATION
PRODUCED BY DEEP LAYER FORCING AHEAD OF THE UPPER TROUGH/ASSOCIATED
COLD FRONT...OR SHOWERS COULD PERSIST THROUGH THE DAY. THUS...HIGH
TEMPERATURES AND DETAILS REGARDING TIMING...DISTRIBUTION AND
MAGNITUDE OF POPS REMAIN UNCERTAIN. AS OF THE SUNDAY AFTERNOON
FORECAST PACKAGE...THE WEDNESDAY FORECAST INDICATES HIGH TEMPERATURES
IN THE LOWER TO MID 70S MOST AREAS...ACCOMPANIED BY CHANCE POPS.
HOWEVER...SIGNIFICANT FORECAST ADJUSTMENTS COULD EVENTUALLY BE
REQUIRED.

WE CONTINUE TO ASSESS THE POTENTIAL FOR THUNDERSTORM DEVELOPMENT
AHEAD OF COLD FROPA WEDNESDAY....ESPECIALLY IN THE AFTERNOON.
09/12Z MODELS CONTINUE TO DEPICT LITTLE TO NO SURFACE BASED
INSTABILITY...BUT A STRENGTHENING LOW LEVEL WIND FIELD WILL PROVIDE
INCREASING AMBIENT SHEAR. WHILE LATEST FORECAST PARAMETERS DO NOT
COMPEL A MENTION OF THUNDER...WE WILL CONTINUE TO ASSESS THE
POTENTIAL FOR HIGH SHEAR/LOW CAPE CONVECTION AHEAD OF THE STRONG
COLD FRONT WEDNESDAY AFTERNOON/EVENING.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
THE STRONG COLD FRONT WILL QUICKLY PUSH THROUGH THE REGION AND WELL
OFFSHORE WEDNESDAY NIGHT...PERHAPS ACCOMPANIED BY A FEW LINGERING
SHOWERS UNTIL LATE EVENING...AS YET ANOTHER MUCH COOLER AIR MASS
SWEEPS INTO THE REGION. HIGH PRESSURE WILL BUILD INTO THE AREA AND
WILL PROVIDE MUCH BELOW BELOW NORMAL TEMPERATURES THURSDAY...PERHAPS
ACCOMPANIED BY A FROST AND/OR FREEZE AWAY FROM THE COAST THURSDAY
NIGHT/EARLY FRIDAY. THEN...GRADUAL MODERATION/TEMPERATURE RECOVERY
WILL FOLLOW FRIDAY THROUGH SATURDAY. A MAINLY DRY/WEAK COLD FRONT
WILL PUSH THROUGH LATE NEXT WEEKEND WITH LITTLE/NO IMPACT ON
TEMPERATURES.

LAKE WINDS...DUE TO THE ELEVATED POTENTIAL FOR GUSTY WINDS/ROUGH
WAVES ON LAKE MOULTRIE WEDNESDAY INTO THURSDAY...ESPECIALLY
THURSDAY...ADDED A MENTION OF A POSSIBLE LAKE WIND ADVISORY TO THE
HAZARDOUS WEATHER OUTLOOK.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
VFR CONDITIONS WILL PREVAIL THROUGH 18Z MONDAY.

EXTENDED AVIATION OUTLOOK...MAINLY VFR THROUGH THE EARLY PART OF THE
WEEK. FLIGHT RESTRICTIONS POSSIBLE ASSOCIATED WITH A COLD FRONT MID
WEEK. WINDS WILL BECOME A CONCERN BEHIND THE FRONT LATE WEDNESDAY
NIGHT AND/OR THURSDAY.

&&

.MARINE...
TONIGHT...CONDITIONS ACROSS THE COASTAL WATERS WILL REMAIN FAIRLY
BENIGN...WITH HIGH PRESSURE ANCHORED TO THE SOUTH AND A BROAD
TROUGH AND DECAYING COLD FRONT TO THE NORTH/NORTHWEST. A LATE
AFTERNOON SEABREEZE WILL SUPPORT SOUTH/SOUTHWEST WINDS UNTIL
AROUND SUNSET...WHEN SYNOPTIC FLOW BACKS TO THE WEST. WIND SPEEDS
WILL REMAIN 15 KT OR LESS...WITH WAVES 3 FT OR LESS AND COMPOSED
MAINLY OF A 10 TO 12 SECOND BACK SWELL.

MONDAY THROUGH THURSDAY...CONDITIONS WILL REMAIN RELATIVELY TRANQUIL
MONDAY/TUESDAY BEFORE WINDS/SEAS INCREASE SIGNIFICANTLY IN THE
WEDNESDAY/THURSDAY TIME FRAME. BETWEEN A TROUGH OF LOW PRESSURE TO
THE NORTH AND WEAK HIGH PRESSURE TO THE SOUTH...OFFSHORE FLOW 15 KT
OR LESS WITHIN 20 NM OF THE COAST/20 KT OR LESS BEYOND 20 NM WILL
PREVAIL...INTERRUPTED BY THE SEA BREEZE CIRCULATION BOTH AFTERNOONS.
THIS WILL RESULT IN SEAS GENERALLY 2-4 FT...HIGHEST BEYOND 20 NM.
CONDITIONS WILL THEN RAMP UP STARTING LATE TUESDAY NIGHT/WEDNESDAY
AS THE SOUTHWEST SURFACE PRESSURE GRADIENT/LOW LEVEL WINDS INCREASE
AHEAD OF AN APPROACHING COLD FRONT. SMALL CRAFT ADVISORY CONDITIONS
COULD DEVELOP AHEAD OF FRONT WEDNESDAY.

ALSO OF NOTE TUESDAY THROUGH WEDNESDAY...MARINE STRATUS/SEA FOG
COULD DEVELOP. HOWEVER...09/12Z GUIDANCE DIFFERS REGARDING THE
DEGREE OF DEWPOINT RECOVERY AHEAD OF THE APPROACHING COLD FRONT.
ALSO...INCREASING SW WINDS COULD LIMIT THE POTENTIAL FOR SIGNIFICANT
FOG. DUE TO THESE FACTORS...FORECAST CONFIDENCE REMAINS INSUFFICIENT
TO JUSTIFY A MENTION OF SEA FOG WITHIN THE HAZARDOUS WEATHER
OUTLOOK.

WEDNESDAY NIGHT...THE STRONG COLD FRONT WILL PUSH THROUGH THE WATERS
AND WINDS WILL SHIFT TO THE NORTHWEST. A TIGHTENING PRESSURE
GRADIENT AND COLD ADVECTION WILL SUPPORT INCREASING WINDS AND
BUILDING SEAS. A PERIOD OF SMALL CRAFT ADVISORIES APPEARS HIGHLY
LIKELY WEDNESDAY NIGHT INTO THURSDAY...AND THE PROBABILITY FOR GALES
IS SUFFICIENT TO JUSTIFY A MENTION OF OVER THE OUTER GEORGIA WATERS.

AS HIGH PRESSURE BUILDS TOWARD THE WATERS...THE SURFACE PRESSURE
GRADIENT WILL RELAX AND WINDS/SEAS WILL IMPROVE THURSDAY AFTERNOON
THROUGH FRIDAY.

&&

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

&&

$$

NEAR TERM...WMS
SHORT TERM...SPR
LONG TERM...BSH
AVIATION...SPR/WMS
MARINE...SPR/WMS