Area Forecast Discussion
Issued by NWS Charleston, SC

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000
FXUS62 KCHS 262041
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
341 PM EST WED NOV 26 2014

.SYNOPSIS...
HIGH PRESSURE FROM THE GULF OF MEXICO WILL EXTEND ACROSS THE AREA
TONIGHT...GIVING WAY TO A DRY COLD FRONT LATE TONIGHT AND THURSDAY
MORNING. HIGH PRESSURE WILL THEN BUILD INTO THE SOUTHEAST UNITED
STATES AND PREVAIL THROUGH EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE MEAN LARGE SCALE TROUGH ALOFT WILL REMAIN OVER THE EASTERN HALF
OF THE NATION THROUGH THE NIGHT. ANOTHER SHORT WAVE MOVING THROUGH
THE MID MS VALLEY INTO THE TN VALLEY THIS EVENING WILL SWEEP RAPIDLY
EASTWARD THROUGH THE TROUGH LATE TONIGHT AS IT REACHES NEAR OUR
NORTH AND NW ZONES BY DAYBREAK. THIS WILL DRIVE A FAST MOVING AND
DRY COLD FRONT TRAILING FROM A CLIPPER TYPE LOW INTO THE AREA AFTER
3 OR 4 AM. THE FRONT WILL ARRIVE DRY...INSTEAD ACCOMPANIED BY
FEW-SCATTERED STRATOCUMULUS AND/OR ALTOCUMULUS.

LINGERING DIURNAL CUMULUS CLOUDS WILL FADE WITH SUNSET THIS EVENING
AND CLEAR SKIES WILL PREVAIL FOR MUCH OF THE NIGHT. THE TROPOSPHERE
WILL DECOUPLE THIS EVENING AND TEMPS WILL FALL QUICKLY...BUT GIVEN
THE WET GROUNDS THE RADIATIONAL COOLING WILL NOT BE IDEAL. TEMPS
WILL START TO HOLD STEADY IN ADVANCE OF THE COLD FRONT LATE THIS
EVENING AND OVERNIGHT AS THE SYNOPTIC FLOW BACKS A LITTLE TO THE
SW...BEFORE COLD ADVECTION ARRIVES IN WAKE OF THE FRONT AFTER 5 OR 6
AM. FOR THE THIRD MORNING IN A ROW THIS WILL SUPPORT ACTUAL MIN
TEMPS OCCURRING AROUND 8-9 AM...RANGING FROM THE UPPER 30S WELL
INLAND TO AROUND 40 NEAR THE US-17 CORRIDOR...WITH LOWER AND MIDDLE
40S ON THE ISLAND COMMUNITIES.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THURSDAY...DRY CONDITIONS ARE ANTICIPATED AS THE AREA REMAINS ALONG
THE SOUTHERN EDGE OF A MID LVL TROUGH AXIS PASSING ALOFT. GUSTY
WINDS APPEAR LIKELY THROUGH MUCH OF THE DAY WHILE STRONG LOW LVL
WINDS SHIFT OVER THE REGION DURING PEAK HEATING. IN GENERAL...MOST
AREAS SHOULD SEE WIND GUSTS BETWEEN 20-25 MPH. NORTHWEST FLOW ALONG
THE LEADING EDGE OF HIGH PRESSURE BUILDING FROM CENTRAL UNITED
STATES WILL ALSO RESULT IN COOLER OVERALL TEMPS...WITH AFTERNOON
HIGHS ONLY IN THE UPPER 50S OVER MOST AREAS. A FEW LOCATIONS COULD
PEAK AT 60 DEGREES SOUTH OF INTERSTATE 16 IN SOUTHEAST GEORGIA.
OVERNIGHT LOWS WILL RANGE BETWEEN THE LOW/MID 30S AWAY FROM THE
COAST...WITH FREEZING TEMPS INLAND.

LAKE WINDS...A 35-40 KT LOW LVL WIND FIELD WILL SHIFT OVER THE AREA
INTO MUCH OF THURSDAY...RESULTING IN LAKE WIND ADVISORY CONDITIONS
AS WARMER WATERS MIX WINDS TO THE SFC. A LAKE WIND ADVISORY WILL
THEREFORE BE IN EFFECT THROUGH 5 PM THURSDAY.

FRIDAY AND SATURDAY...WE SHOULD EXPERIENCE THE COLDEST TEMPS OF THE
WEEK ON FRIDAY AS SFC HIGH PRESSURE BECOMES CENTERED OVER THE
SOUTHEAST ALONG THE BACK EDGE OF A MID/UPPER LVL TROUGH AXIS
SHIFTING OFF THE EASTERN SEABOARD. OVERALL HIGH TEMPS SHOULD RANGE
IN THE LOW 50S OVER NORTHERN AREAS TO UPPER 50S IN SOUTHEAST
GEORGIA. A DECENT RADIATIONAL COOLING SETUP WILL LIKELY RESULT IN
FRIDAY NIGHT LOWS BETWEEN THE LOW TO MID 30S...WITH FREEZING TEMPS
INLAND. DRY CONDITIONS WILL PERSIST INTO SATURDAY...BUT TEMPS SHOULD
SLOWLY WARM AS WEAK MID/UPPER LVL RIDGING OCCURS AND A LIGHT
SOUTHERLY SFC FLOW RETURNS IN RESPONSE TO THE CENTER OF SFC HIGH
PRESSURE DRIFTING OFFSHORE. LATEST 1000-850 MB THICKNESS VALUES
SUPPORT OVERALL HIGH TEMPS IN THE LOW/MID 60S ON SATURDAY...WARMEST
IN SOUTHEAST GEORGIA.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
THE CENTER OF SURFACE HIGH PRESSURE WILL SLOWLY SETTLE OVER THE
NEARBY ATLANTIC WATERS LATE SATURDAY INTO MONDAY...WHILE AN UPPER
RIDGE BUILDS FROM THE EASTERN GULF OF MEXICO. EXPECT A WARMING
TREND TO CONTINUE THROUGH MONDAY AS A RESULT...WITH HIGH
TEMPERATURES REBOUNDING INTO THE UPPER 60S TO AROUND 70 DEGREES
SUNDAY AND MONDAY AFTERNOON...AND NIGHTTIME LOWS FALLING INTO THE
40 DEGREE RANGE. A COLD FRONT FORMING THE LEADING EDGE OF ANOTHER
STRONG SURFACE HIGH PRESSURE WILL APPROACH FROM THE NORTHWEST ON
TUESDAY. THE FRONT COULD STALL OVER OR JUST NORTH OF THE FORECAST
AREA WEDNESDAY...AS THE SURFACE HIGH BUILDS AN INLAND WEDGE FROM
THE MID ATLANTIC STATES INTO THE CAROLINAS AND NORTHERN GEORGIA.
NORTHEAST FLOW WITHIN THIS PATTERN WILL CONTRIBUTE TO A SLIGHT
COOL DOWN FOR THE MID WEEK PERIOD. A COASTAL TROUGH ON THE EDGE OF
THE INLAND WEDGE COULD SUPPORT A SLIGHT CHANCE FOR RAIN LATE
TUESDAY INTO WEDNESDAY.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
VFR WEATHER WILL PREVAIL FOR THE 18Z TAF CYCLE. ANOTHER COLD FRONT
WILL CROSS THE TERMINALS DURING EARLY WEDNESDAY MORNING...FOLLOWED
BY A PERIOD OF WIND SHEAR AT BOTH AIRFIELDS WITH THE PASSAGE OF A
35-40 KT LOW LEVEL JET. THIS WILL TRANSITION INTO GUSTY SURFACE
WINDS BY MID MORNING WEDNESDAY AS THESE HIGHER WINDS MIX DOWN TO THE
SURFACE. WEST/NW WINDS WILL REACH 15-25 KT FROM AROUND 1330Z-18Z AT
BOTH KSAV AND KCHS.

EXTENDED AVIATION OUTLOOK...VFR CONDITIONS WILL PREVAIL.

&&

.MARINE...
TONIGHT...WE STILL HAVE A MARGINAL SMALL CRAFT ADVISORY ON THE
CHARLESTON COUNTY ATLANTIC WATERS AND OUTERMOST GA WATERS INTO
THIS EVENING...WITH NO HEADLINES ELSEWHERE. CONDITIONS WILL
IMPROVE LATER THIS EVENING INTO THE OVERNIGHT HOURS AS HIGH
PRESSURE FROM THE GULF OF MEXICO EXTENDS ACROSS THE LOCAL WATERS.
HOWEVER...A COLD FRONT WILL APPROACH THE MARINE COMMUNITY CLOSER
TO DAYBREAK...AND WE/LL NEED TO HOIST SMALL CRAFT ADVISORIES AGAIN
FOR THE ENTIRE REGION AS COLD ADVECTION DEVELOPS BEHIND THE FRONT.
WE WON/T DO THIS THOUGH UNTIL AFTER THE CURRENT ADVISORY CONDITIONS
COME TO AN END.

THURSDAY THROUGH MONDAY...ELEVATED WINDS/SEAS WILL LIKELY DEVELOP
THURSDAY WHILE A SURGE OF COLD AIR ADVECTION OCCURS OVER THE
WATERS ALONG WITH A TIGHTENING PRESSURE GRADIENT ON THE EDGE OF
HIGH PRESSURE BUILDING INLAND. AS A RESULT...SMALL CRAFT
ADVISORIES WILL BE NEEDED FOR ALL WATERS INCLUDING THE CHS HARBOR
ON THURSDAY. EXPECT ADVISORY LEVEL WINDS/SEAS THROUGH AT LEAST
THURSDAY EVENING...WITH CONDITIONS IMPROVING OVER THE CHS HARBOR
BY EARLY THURSDAY NIGHT...THEN OVER REMAINING WATERS BY FRIDAY
MORNING AS HIGH PRESSURE BECOMES MORE CENTERED ALONG THE SOUTHEAST
COAST. MARINE CONDITIONS WILL CONTINUE TO IMPROVE FRIDAY AFTERNOON
INTO THE WEEKEND WHILE SURFACE HIGH PRESSURE BECOMES CENTERED OVER
THE WATERS...ALLOWING THE PRESSURE GRADIENT TO RELAX.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
SC...LAKE WIND ADVISORY FROM 6 AM TO 5 PM EST THURSDAY FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY UNTIL 7 PM EST THIS EVENING FOR AMZ350-
     374.

&&

$$

NEAR TERM...
SHORT TERM...
LONG TERM...WMS
AVIATION...
MARINE...





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