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000
FXUS62 KCHS 090822
AFDCHS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
422 AM EDT SUN MAR 9 2014

.SYNOPSIS...
HIGH PRESSURE WILL GENERALLY PREVAIL EARLY THIS NEXT WEEK...SUPPORTING
A CONTINUED WARMING TREND. A STRONG COLD FRONT WILL MOVE THROUGH THE
AREA DURING THE MIDDLE OF NEXT WEEK...FOLLOWED BY COOL HIGH PRESSURE
LATE IN THE WEEK INTO NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
TODAY...A LOW AMPLITUDE AND DEEP LAYERED TROUGH WILL PIVOT OFF THE
NE AND MID ATLANTIC COASTS...WITH AN ASSOCIATED AND STRETCHED OUT
MID LEVEL VORTICITY FIELD TO DROP SOUTH/SE TO NEAR THE CENTRAL
APPALACHIANS AND THE NC/SC BORDER BY LATE. AT THE SURFACE WE FIND
AN ELONGATED AND FAIRLY INDISTINCT RIDGE FROM TEXAS ACROSS THE
NORTHERN GULF OF MEXICO TO THE SW ATLANTIC OFF THE FLORIDA COAST.
BUT CLOSER BY IS A BROAD LEE SIDE TROUGH THAT PERSISTS INLAND OVER
THE SE THROUGHOUT THE DAY...WHILE AN UPSTREAM COLD FRONT THAT IS
BECOMING PARALLEL TO THE FLOW ALOFT RUNS OUT OF STEAM AS IT SHIFTS
INTO THE PEE DEE OF SC BY NIGHTFALL. THERE IS A SMALL INCREASE IN
MID LEVEL MOISTURE...MAINLY BETWEEN ABOUT 10-20K FT...WHICH
INDICATES THAT SKIES WILL TURN OUT TO BE PARTLY CLOUDY OR MOSTLY
SUNNY.

AS A RESULT OF THIS SYNOPTIC SET UP WE FIND A DEEP WESTERLY FLOW
THROUGHOUT JUST ABOUT ALL OF THE TROPOSPHERE. SUFFICE TO SAY WITH
CONSIDERABLE DRY AIR AND LARGE SCALE SUBSIDENCE IT/LL BE ANOTHER
RAINFREE DAY WITH A CONTINUATION OF OUR WARMING TREND. THE
1000-850 MB THICKNESS FORECAST SHOWS AN INCREASE OF ABOUT 6-12
METERS FROM YESTERDAY...AND WHEN COMBINED WITH DOWNSLOPE/COMPRESSIONAL
HEATING AND AMPLE INSOLATION WE/RE LOOKING FOR TEMPS PEAKING
BETWEEN 73-76 OVER THE VAST MAJORITY OF THE CWFA. THE RESULTANT
SEA BREEZE WILL HAVE DIFFICULTY IN DEVELOPING WITH THE OFFSHORE
TRAJECTORIES...BUT IT DOES KICK IN DURING THE MID/LATE
AFTERNOON...HOLDING TEMPS DOWN IN THE 60S ON THE BEACHES.

TONIGHT...WHAT REMAINS OF THE POORLY DEFINED COLD FRONT SHIFTS
INTO THE ATLANTIC OFF THE SC COAST EARLY ON. TIME CROSS-SECTIONS
AND SOUNDINGS SHOW THAT WHAT LITTLE MOISTURE REMAINS DRIES OUT
QUICKLY AS THE STRUNG OUT VORTICITY LOBE AND ASSOCIATED UPPER JET
PULLS THROUGH. THIS RESULTS IN SKIES THAT ARE PARTLY CLOUDY NORTH
BECOMING MOSTLY CLEAR...AND MOSTLY CLEAR/CLEAR SKIES SOUTH. THERE
IS VERY WEAK COOL ADVECTION THAT TRANSPIRES OVERNIGHT WITH AN
OFFSHORE SYNOPTIC FLOW. THE END RESULT IS FOR MINS DOWN INTO THE
MID AND UPPER 40S INLAND...WITH LOWER 50S NEAR/ALONG THE COAST.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
MONDAY AND MONDAY NIGHT...ZONAL FLOW ALOFT WILL GRADUALLY AND
SUBTLY TURN MORE ANTICYCLONIC AS A SHORTWAVE RIDGE TRANSLATES
EASTWARD. A WEAK SURFACE HIGH WILL REMAIN SOUTH OF THE REGION AND
PLENTIFUL DRY AIR WILL BE IN PLACE ACROSS THE FORECAST AREA. LOW
LEVEL WESTERLY FLOW AND CLEAR SKIES WILL RESULT IN A VERY MILD DAY
WITH HIGHS REACHING THE UPPER 70S IN MOST LOCATIONS. IN FACT...THESE
TYPES OF TEMPERATURES WILL RUN NEARLY 10 DEGREES ABOVE NORMAL.
OVERNIGHT LOWS WILL BE WARM AS WELL...RANGING FROM AROUND 50 TO THE
LOW 50S IN MOST AREAS.

TUESDAY THROUGH WEDNESDAY...THE PATTERN WILL BECOME MORE ACTIVE
THROUGH THE MIDDLE OF THE WEEK AS A SOUTHERN STREAM CLOSED LOW MOVES
EASTWARD ACROSS THE NORTHERN GULF OF MEXICO. BY WEDNESDAY...THIS
FEATURE WILL DAMPEN OUT CONSIDERABLY AND WILL BEGIN TO PHASE WITH A
MORE SIGNIFICANT NORTHERN STREAM TROUGH DIVING OUT OF THE UPPER
MIDWEST. THE COMBINATION OF THESE TWO MID/UPPER LEVEL DISTURBANCES
WILL DRIVE A DEVELOPING LOW PRESSURE SYSTEM ACROSS THE MID
MISSISSIPPI VALLEY INTO THE CENTRAL APPALACHIANS LATE TUESDAY NIGHT
AND WEDNESDAY MORNING. THIS DEEPENING SYSTEM WILL DRAG A STRONG COLD
FRONT ACROSS THE SOUTHEAST AND EVENTUALLY THE FORECAST AREA BY
WEDNESDAY. RAIN CHANCES RAMP UP STARTING TUESDAY NIGHT AND WILL
REACH THEIR PEAK SOMETIME AROUND WEDNESDAY MORNING. THE MODELS ARE
ACTUALLY IN PRETTY GOOD AGREEMENT REGARDING THE TIMING OF THE
ARRIVAL OF THE FRONT AND THE TRACK OF THE SURFACE LOW. THE BIGGEST
QUESTION REVOLVING AROUND THE TIMING OF THE FRONT IS THE POTENTIAL
FOR THUNDERSTORM DEVELOPMENT ON WEDNESDAY. CURRENT MODELS SHOW
LITTLE TO NO SURFACE BASED INSTABILITY...WITH A STRENGTHENING LOW
LEVEL WIND FIELD PROVIDING INCREASING AMBIENT SHEAR. ALSO OF NOTE IS
THE SOUTHERN STREAM WAVE THAT IS WEAKENING WITH TIME AS THE UPPER
MIDWEST SHORTWAVE BECOMES THE DOMINANT FEATURE. I HAVE NOT ADDED ANY
MENTION OF THUNDER TO THE FORECAST AT THIS POINT...BUT IT BEARS
WATCHING OVER THE NEXT COUPLE OF DAYS. TUESDAY WILL BE ANOTHER WARM
DAY WITH WELL ABOVE NORMAL TEMPERATURES...WHILE WEDNESDAY WILL BE
ABOVE NORMAL BUT NOT QUITE AS MUCH.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
THE STRONG COLD FRONT WILL QUICKLY PUSH WELL OFFSHORE WEDNESDAY
NIGHT AS A MUCH COOLER AIRMASS MOVES IN BEHIND IT. HIGH PRESSURE
WILL BUILD IN FROM THE SOUTHWEST THROUGH FRIDAY AND THEN SLIP
OFFSHORE. A MAINLY DRY FRONT WILL PUSH THROUGH OVER THE WEEKEND
ASSOCIATED WITH A CLIPPER TYPE LOW WELL TO THE NORTH. AS SUCH...I
HAVE KEPT A SLIGHT CHANCE POP IN FOR WEDNESDAY NIGHT AS THE FRONT
BEGINS TO PUSH OFF TO THE EAST. THEREAFTER THE FORECAST IS DRY.
TEMPERATURES DIP BACK TO WELL BELOW NORMAL FOR THURSDAY AS THERE IS
A NOTABLE AIRMASS CHANGE. TEMPERATURES THEN GRADUALLY REBOUND BACK
TO NEAR NORMAL FOR THE WEEKEND.

&&

.AVIATION /08Z SUNDAY THROUGH THURSDAY/...
VFR THROUGH 06Z 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...
TODAY AND TONIGHT...CONDITIONS ACROSS THE MARINE COMMUNITY ARE
SOMEWHAT LACKADAISICAL WITH HIGH PRESSURE ANCHORED TO THE SOUTH AND
A BROAD TROUGH AND DECAYING COLD FRONT TO OUR NORTH/NW. THIS WILL
PRODUCE MAINLY WESTERLY WINDS OF NO MORE THAN AROUND 10 OR 15
KT...ALTHOUGH TYPICAL SEA BREEZE CIRCULATIONS WILL CAUSE WINDS TO
SHIFT TO MORE SW THIS AFTERNOON/EVENING. THE BULK OF THE WAVE
SPECTRUM WILL BE COMPRISED OF A 10-12 SECOND BACK SWELL THAT HAS
ORIGINATED FROM THE MONSTROUS AND DEEP LOW IN THE NW ATLANTIC...WITH
OVERALL SIGNIFICANT WAVE HEIGHTS LIMITED TO 2 OR 3 FT.

MONDAY THROUGH THURSDAY...THE FORECAST PERIOD WILL START OFF QUITE
TRANQUIL THROUGH TUESDAY BEFORE WINDS/SEAS INCREASE SIGNIFICANTLY IN
THE WEDNESDAY/THURSDAY TIME FRAME. A RELATIVELY WEAK PRESSURE REGIME
WITH WEAK HIGH PRESSURE TO THE SOUTH WILL BE IN PLACE MONDAY AND
TUESDAY. THIS WILL RESULT IN WEST/SOUTHWEST FLOW AT 15 KT OR LESS
AND SEAS GENERALLY 2-3 FT. CONDITIONS WILL THEN RAMP UP STARTING ON
WEDNESDAY AS A STRONG COLD FRONT PUSHES THROUGH. AS THE FLOW TURNS
MORE WESTERLY AND NORTHWESTERLY INTO THURSDAY...A TIGHTENING PRESSURE
GRADIENT AND COLD ADVECTION WILL LEAD TO INCREASING WINDS/SEAS. A
PERIOD OF SMALL CRAFT ADVISORIES APPEARS HIGHLY LIKELY WEDNESDAY
NIGHT INTO THURSDAY...WITH EVEN A LOW END CHANCE FOR GALES MAINLY
OVER THE OUTER GEORGIA WATERS.

&&

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

&&

$$

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