Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 242336
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
636 PM EST MON NOV 24 2014

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA FROM THE WEST TONIGHT. LOW PRESSURE
WILL THEN DEVELOP OFF THE CAROLINA COAST AND MOVE UP THE ATLANTIC
SEABOARD TOMORROW NIGHT AND WEDNESDAY. AN UPPER LEVEL SYSTEM WILL
CROSS WESTERN NORTH CAROLINA EARLY THURSDAY. DRY HIGH PRESSURE WILL
RETURN FRIDAY AND LINGER INTO THE WEEKEND.

&&

.NEAR TERM /THROUGH TUESDAY/...
AT 630 PM...LATEST IMAGES FROM KGSP AND TCLT INDICATED A BROKEN BAND
OF QUICKLY MOVING SHOWERS EAST OF THE CLT TERMINAL. MODEL GUIDANCE
AND RADAR TRENDS INDICATE THAT THE SHOWER ACTIVITY WILL REMAIN EAST
OF THE REGION. I WILL UPDATE THE FORECAST TO ADD SCHC TO CHC POPS
ACROSS THE EXTREME EASTERN PIEDMONT THROUGH MID EVENING.
OTHERWISE...THE CURRENT FORECAST APPEARS IN GOOD SHAPE.

AS OF 225 PM EST...REGIONAL RADARS SHOW ISOLATED SHOWERS BRUSHING
THE LOWER PIEDMONT FROM SE OF GREENWOOD TO NEAR CHESTER TO SE OF
MONROE. THIS SHOULD BE THE WESTWARD EXTENT OF ANY ADDITIONAL
ACTIVITY THROUGH THE AFTN...AND ANY SFC BASED INSTABILITY AHEAD OF
THE APPROACHING FRONT SHOULD BE LIMITED TO A FEW HUNDRED J/KG OR
LESS IN THE PIEDMONT THROUGH LATE DAY GIVEN THE WARM TEMPERATURES
ALOFT. THE APPROACHING COLD FRONT WAS ANALYZED FROM EAST OF
CROSSVILLE TN TO W OF ATLANTA THIS AFTN. THIS MOSTLY DRY BOUNDARY
SHOULD MOVE THROUGH THE MOUNTAINS THIS EVENING AND THEN SLOWLY
SETTLE EAST OF THE AREA THROUGH THE EARLY OVERNIGHT HOURS. WEAK COLD
ADVECTION BEHIND THE FRONT WILL LEAD TO ONLY MODEST COOLING AND MINS
AT LEAST 5 TO 10 DEGREES ABOVE CLIMO.

ADDITIONAL H5 HEIGHT FALLS ARE EXPECTED FROM THE SRN PLAINS TO THE
LOWER MS RIVER VALLEY TUESDAY. MID AND UPPER LEVEL MOISTURE WILL
FILL IN OVERHEAD ACROSS OUR REGION IN RESPONSE TO THE SHARPENING
TROUGH TO THE WEST AND SFC LOW PRESSURE DEVELOPING OFF THE FL/GA
COAST TO THE SE. HOWEVER...LOWER LEVELS ACROSS OUR REGION WILL
REMAIN FAIRLY DRY AS THE SFC TO 850 MB WINDS REMAIN A WESTERLY TO NW
DOWNSLOPE. WILL KEEP MAX TEMPS A SHADE ON THE COOLER SIDE OF
GUIDANCE DUE TO THE HIGH CLOUDINESS THROUGH TUESDAY.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AT 230 PM EST MONDAY...ON TUESDAY EVENING AND UPPER TROUGH WILL BE
LOCATED OVER THE MS RIVER VALLEY. CHANNELED SHORTWAVE ENERGY WILL BE
CROSSING GA AND THE CAROLINAS...WHILE A STRONG SHORTWAVE MOVES
THROUGH THE BASE OF THE TROUGH OVER THE WESTERN GULF STATES. THIS
SHORTWAVE CROSSES OUR AREA WEDNESDAY MORNING...FOLLOWED BY A STRONG
CHANNELED VORT LOBE FORM THE MID MS RIVER VALLEY ON WEDNESDAY
EVENING. HEIGHTS RISE ALOFT ON THURSDAY AS THE UPPER TROUGH AXIS
PROGRESSES OFF THE EAST COAST.

AT THE SURFACE...ON TUESDAY EVENING A STATIONARY FRONT WILL BE
LOCATED OVER THE GULF STREAM OFF THE COAST OF GA AND THE CAROLINAS.
A SURFACE WAVE WILL DEVELOP ALONG THIS BOUNDARY OVERNIGHT...
SOMEWHERE NEAR THE SC COAST. LOW LEVEL MOISTURE WILL SPREAD WELL
INLAND AS A DEFORMATION ZONE APPEARS TO DEVELOP NW OF THE LOW.
ISENTROPIC UPGLIDE OVER THE FRONT DOES NOT APPEAR TO EXTEND AS FAR
WEST AS OUR AREA...LIMITING RAINFALL AMOUNTS UNDER MODEST UPWARD
VERTICAL MOTION. MODULE THICKNESS VALUES AND VERTICAL PROFILES SUPPORT
WITHER A RAIN OR SNOW SCENARIO...WITH RAIN EAST OF THE BLUE
RIDGE...AND SNOW IN THE MOUNTAINS. SNOWFALL TOTALS COULD APPROACH
ADVISORY CRITERIA ON TUESDAY NIGHT AND EARLY WEDNESDAY IN THE NC
MOUNTAINS.

RAPID DRYING WILL OCCUR EARLY WEDNESDAY IN THE WAKE OF THE DEPARTING
SURFACE WAVE. MEANWHILE...A SURFACE WAVE WILL MOVE SOUTHEAST ACROSS
THE PLAINS AND MID MS RIVER VALLEY. MOISTURE AHEAD OF THIS FEATURE
WILL REACH THE NC MOUNTAINS WEDNESDAY AFTERNOON...WITH VERTICAL
PROFILES AND THICKNESS SUPPORTING SNOW IN THE MOUNTAINS. THERE
REMAINS SOME DISCREPANCY BETWEEN THE MODELS ON HOW FAR SOUTH THIS
MOISTURE WILL EXTEND. ALTHOUGH THE SOME MODELS SHOW THIS MOISTURE
EXTENDING EAST ALONG THE INTERSTATE 40 CORRIDOR...ROBUST NW
DOWNSLOPE FLOW LIMITS CONFIDENCE ON ANY SNOWFALL EAST OF THE
MOUNTAINS. MOIST NW UPSLOPE FLOW WILL CONTINUE INTO THURSDAY BEHIND
THIS SYSTEM. SNOWFALL TOTALS WITH THE SECOND SYSTEM ARE EXPECTED TO
BE BELOW ADVISRY CRITERIA AT THIS TIME.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 215 PM MONDAY...THE MEDIUM RANGE LOOKS QUIET...AS CANADIAN
HIGH PRES SETTLES OVER THE REGION FOR FRIDAY INTO SATURDAY...UNDER
FLATTENING UPPER FLOW ALOFT. AN UPPER RIDGE THEN BUILDS OVER THE
SOUTHEAST STATES SUNDAY THRU TUESDAY...WHILE SFC HIGH SETTLES JUST
EAST OF THE SOUTH ATLANTIC COAST. THE RESULT IS DRY WEATHER AND A
WARMING TREND TO ABOVE NORMAL TEMPS SUNDAY AND MONDAY. THE 00Z/24
ECMWF HAS A BACKDOOR COLD FRONT PUSH INTO THE NC PIEDMONT BY MIDDAY
MONDAY...WHILE THE 12/24 GFS KEEPS THE FRONT NORTH OF THE AREA. I
STAYED CLOSE TO THE WPC GUIDANCE...WHICH BRINGS IN SOME CLOUDS AND A
SMALL CHC FOR PRECIP MONDAY NIGHT.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
AT KCLT...AT 630 PM...LATEST IMAGES FROM KGSP AND TCLT INDICATED A
BROKEN BAND OF QUICKLY MOVING SHOWERS EAST OF THE CLT TERMINAL.
MODEL GUIDANCE AND RADAR TRENDS INDICATE THAT THE SHOWER ACTIVITY
WILL REMAIN EAST OF THE REGION. THE GREATEST CONCERN WILL BE THE
POSSIBLE ARRIVAL OF RESTRICTIVE CEILINGS DURING THE PRE DAWN HOURS.
THE NAM...TO A LESSER AMOUNT THE GFS...SHOWS A FIELD OF MVFR
CEILINGS PUSH ACROSS THE CLT AREA LATE TONIGHT IN ADVANCE OF A
DEVELOPING COASTAL LOW. BASED ON THE FORECAST SOUNDINGS...I WILL
FORECAST A PERIOD OF MVFR CEILINGS FRO 9Z-11Z. THE LOW CLOUDS WILL
LIKELY DEVELOP ALONG AND AHEAD OF A PASSING COLD FRONT...FROPA
AROUND 9Z. ONCE THE FRONT PASSES...WINDS SHOULD VEER FROM THE NW
BETWEEN 5-10KTS AND REMAIN THROUGH THE REST OF THE TAF PERIOD.

ELSEWHERE...VFR. A COLD FRONT WILL SWEEP ACROSS THE REGION TONIGHT.
VEER WINDS WILL OCCUR AS THE FRONT PASSES...WITH ALL TERMINALS
OBSERVING NW WINDS BEFORE SUNRISE. KAVL WILL LIKELY SEE MARGINAL
GUSTS DURING THE EARLY MORNING HOURS. CLOUDS WILL INCREASE THROUGH
THE DAY ON TUESDAY AS A COASTAL LOW DEVELOPS AND TRACKS NE.

OUTLOOK...COASTAL LOW PRESSURE WILL DEEPEN AHEAD OF AN APPROACHING
TROUGH FROM THE WEST TUE NIGHT INTO WED. ANOTHER UPPER LEVEL WAVE
WILL CROSS THE REGION WED NIGHT INTO THU. PRECIPITATION AND
ASSOCIATED RESTRICTIONS FROM THESE FEATURES MAY RETURN IN THE FORM
OF A WINTRY MIX FROM KAVL TO KHKY...WITH MAINLY RAIN EXPECTED FROM
KGSP TO KCLT AND POINTS SOUTH. DRIER CONDITIONS WILL RETURN BY LATE
WEEK.

CONFIDENCE TABLE...

            23-05Z        05-11Z        11-17Z        17-18Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE HOURLY
EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE FORECASTS
ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...CSH
NEAR TERM...NED
SHORT TERM...JAT
LONG TERM...ARK
AVIATION...NED


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