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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
336 AM EDT MON MAR 30 2015

.SYNOPSIS...
A COLD FRONT WILL PUSH THROUGH THE REGION THIS MORNING AHEAD OF 
REBUILDING HIGH PRESSURE FOR TUESDAY.  ANOTHER WEAK COLD FRONT WILL 
ARRIVE ON TUESDAY NIGHT WITH HIGH PRESSURE QUICKLY BUILDING FOR 
WEDNESDAY LASTING THROUGH THURSDAY.  FRIDAY NIGHT WILL BRING THE 
PASSAGE OF ANOTHER COLD FRONT...WITH COOLER AND DRIER HIGH PRESSURE 
PREVAILING FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 230 AM...WE ARE SEEING AN INCREASE IN PRECIP COVERAGE TO THE 
WEST WHERE THE FRONTAL BOUNDARY WAS INTERCEPTING THE STRONGER LOW 
LEVEL JET AND MOISTURE PLUME ACROSS TN/NRN MS. A FEW SHOWERY 
ELEMENTS WERE NOTED OVER ERN TN...BUT THIS WAS PROBABLY NOT REACHING 
THE GROUND. WILL PUT OFF THE ONSET OF PRECIP FOR ANOTHER HOUR OR 
TWO...WHICH HAS THE ADDED BENEFIT OF ALLOWING WARM ADVECTION TO 
BRING THE TEMPS UP ABOVE FREEZING AT THE PEAKS OF THE NC MTNS. ALL 
INDICATIONS REMAIN THAT PRECIP WILL IN FACT BLOSSOM TO THE WEST THRU 
THE PRE-DAWN HOURS AND REACH THE WESTERN CAROLINAS BY/AROUND 
DAYBREAK. A CONTINUED UPWARD TREND TO PRECIP COVERAGE OVER SRN 
MIDDLE TN/NRN AL IS A GOOD INDICATION THAT THE MODELS ARE ON THE 
RIGHT TRACK.

THE MODELS TAKE THE BAND OF PRECIP AHEAD OF THE FRONT EASTWARD 
ACROSS THE FCST AREA FAIRLY RAPIDLY THIS MORNING...AS THE SHORT WAVE 
ROTATES QUICKLY AROUND THE BOTTOM OF THE UPPER TROF. THIS SHOULD 
DRIVE THE SURFACE FRONTAL ZONE EAST OF THE REGION BY MIDDAY. WILL GO 
WITH THE HIGHEST PRECIP PROBABILITY ACROSS THE SRN MOUNTAINS/NE 
GEORGIA/WRN UPSTATE AS THE BEST LOW LEVEL FORCING STRETCHES INTO 
THAT REGION FROM THE WEST EARLY THIS MORNING. COVERAGE SHOULD BE NOT 
AS GREAT ALONG/N OF I-40 WHERE DOWNSLOPE E OF THE MTNS WILL BE 
UNFAVORABLE. WHT REMAINS TO BE SEEN IS IF ANY EMBEDDED THUNDERSTORMS 
CAN SURVIVE INTO THE MORE UNFAVORABLE AIR MASS ACRS N GEORGIA. 
PRECIP CHANCES RAMP DOWN QUICKLY BY MIDDAY. TEMPS SHOULD REBOUND 
NICELY...ABOUT TEN DEGREES ABOVE YESTERDAY...IN SPITE OF THE SFC 
BOUNDARY MOVING THRU...BECAUSE OF THE W/NW DOWNSLOPE FLOW IN THE 
AFTERNOON.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 AM EDT MONDAY...THE SHORT TERM FCST PERIOD INITIALIZES 
TUESDAY MORNING AMIDST CONTINUED NW FLOW PATTERN ALOFT...HIGHLIGHTED 
BY A NORTHERN STREAM SHORTWAVE SLIDING THROUGH THE SOUTHERN GREAT 
LAKES REGION.  WEAK SURFACE CYCLOGENESIS BENEATH WILL AID COLD FRONTAL 
PROGRESSION ACROSS THE MIDWEST INTO THE OHIO VALLEY ON TUESDAY AHEAD 
OF SPRAWLING HIGH PRESSURE.  MEANWHILE ACROSS THE SOUTHERN PLAINS 
ANOTHER SURFACE WAVE WILL FORM IN THE LEE OF THE SOUTHERN ROCKIES 
ALLOWING FOR DEVELOPMENT OF MODEST BAROCLINIC ZONE OVER THE 
SOUTHEAST TUESDAY AFTERNOON INTO WEDNESDAY.  WARM FRONT LEADING THE 
CHARGE NORTHWARD ON TUESDAY WILL ADVANCE INTO THE I20 CORRIDOR LATE 
IN THE DAY WITH ACTIVATION LIKELY AS MORE UNSTABLE AIR ADVECTS 
NORTHWARD.  AS THE ABOVE MENTIONED COLD FRONT CONTINUES TO SLIDE 
SOUTH THROUGH THE TN VALLEY...EXPECTING CONVECTION ALONG THE FRONTAL 
ZONE WHICH COULD PUSH INTO THE WESTERN NC MTNS LATE TUESDAY NIGHT.  
MODELS CONTINUE TO HINT AT SOME RESIDUAL INSTABILITY AFTER SUNSET 
AHEAD OF THE FRONT...HOWEVER DECREASING WITH HEATING LOSS...AND 
DRIER AIR ADVECTION BEHIND THE FRONT AS IT BACK DOORS INTO THE 
REGION.  THE FRONT WILL SLIDE SOUTH THROUGH THE REMAINDER OF THE 
FCST AREA OVERNIGHT...AS HIGH PRESSURE SETS UP ALONG THE EASTERN 
SEABOARD.  BRIEF HEIGHT RISES ALOFT COMBINED WITH RIDGING AT THE 
SURFACE WILL KEEP THE WX DRY ON WEDNESDAY AHEAD OF RETURNING MOIST 
SOUTHERLY UPGLIDE ATOP POSSIBLE INSITU CAD THURSDAY MORNING.

AS FOR THE FCST...POPS WILL SLOWLY INCREASE INTO TUESDAY EVENING 
ACROSS THE NORTHEAST GA AND WESTERN NC MTNS TO ACCOUNT FOR WEAK 
FRONTAL ZONE ASSOCIATED CONVECTION...WITH POPS REMOVED BY MID 
MORNING WEDNESDAY AS THE COLD FRONT SLIDES THROUGH.  POPS WILL 
REMAIN BELOW MENTIONABLE LEVELS THROUGH THE DAY WEDNESDAY BEFORE 
INCREASING MID/LATE EVENING AS MODELS CONTINUE TO HINT AT WEAK 
INSITU CAD REGIME ON THE WESTERN FLANK OF THE COASTAL SFC RIDGE.  GFS 
ISENTROPIC CHARTS INDICATE IMPROVING UPGLIDE IN THE LOW 
LEVELS...THUS CHANCE LEVEL POPS WERE FAVORED OVER THE WESTERN HALF 
OF THE FCST AREA TAPERING TO SLIGHT CHANCE FURTHER EAST ON THE 
FRINGE OF UPGLIDE MAXIMA.  TEMPERATURES THROUGH THE PERIOD WILL 
REMAIN ABOVE NORMAL LEVELS DESPITE THE WEAK FROPA TUESDAY NIGHT.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 315 AM EDT MONDAY...THE MEDIUM RANGE FCST PERIOD INITIALIZES 
THURSDAY MORNING AMIDST ONGOING UPGLIDE/UPSLOPE PRECIP ACROSS MUCH OF 
THE SOUTHWEST NC AND NORTHEAST GA MTNS.  WEAK INSITU CAD REGIME 
RESULTANT FROM ANCHORED COASTAL HIGH OFF THE NC COAST WILL BREAK 
DOWN THROUGH LATE MORNING LEADING TO EROSION OF ANY UPGLIDE 
ENHANCEMENT.  SOUTHERLY FLOW AT THE SURFACE WILL CONTINUE LEADING TO 
IMPROVING WAA REGIME INTO FRIDAY.  MEANWHILE...A NORTHERN STREAM 
UPPER WAVE WILL SLIDE ACROSS THE UPPER MIDWEST WHILE A COLD FRONT 
STRETCHES TO THE SOUTH FROM SUBSEQUENT SFC LOW.  MODELS CONTINUE TO 
PROG THE FRONT ALONG THE OH RIVER VALLEY THURSDAY EVENING WITH AN 
IMPROVING WARM SECTOR AIRMASS OUT AHEAD.  THE ECMWF/GFS TREND 
TOWARDS SOME DISCONTINUITY LATE IN THE WEEK REGARDING TIMING OF THE 
FROPA ACROSS THE SOUTHERN APPS.  THE ECMWF FAVORS A FASTER SOLUTION 
WHICH BRINGS THE FRONT INTO THE MTNS OF WESTERN NC FRIDAY AFTERNOON 
OR EARLY EVENING WITH PERHAPS ISOLATED CONVECTION AHEAD IN THE 
MILDLY UNSTABLE AIRMASS...WHILE THE GFS SEEMS ABOUT 6 HOURS SLOWER 
THAN THAT OF THE ECMWF.  BOTH SOLUTIONS WOULD FAVOR A NOCTURNAL 
FROPA THUS LIMITING THE AMOUNT OF POTENTIAL INSTABILITY AVAILABLE 
FOR CONVECTION.  BEYOND THAT THE FRONT SHOULD EXIT THE REGION TO THE 
EAST BY MIDDAY SATURDAY AT THE LATEST ALLOWING FOR COOLER/DRIER HIGH 
PRESSURE TO ADVECT IN FROM THE WEST.  TEMPERATURES THROUGH THE 
PERIOD WILL WARM TO WELL ABOVE NORMAL LEVELS FOR THURSDAY AND 
FRIDAY...WITH SLIGHTLY COOLER YET STILL ABOVE CLIMO LEVELS FCST FOR 
THE WEEKEND.

&&

.AVIATION /08Z MONDAY THROUGH FRIDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS THRU THE EARLY MORNING HOURS 
AS A PATCH OF LOW CLOUDS WITH A BASE OF 050-060 MOVES EAST ACROSS 
THE PIEDMONT OF THE CAROLINAS. CONDITIONS SHOULD DETERIORATE TOWARD 
DAYBREAK AS A BAND OF PRECIP AHEAD OF A COLD FRONT MOVES IN FROM THE 
WEST. THE PRECIP IS FCST TO FILL IN ALONG THE FRONT AND BRING AT 
LEAST A TEMPORARY MVFR CEILING/VIS RESTRICTION TO ALL TAF SITES 
VARIOUSLY IN THE 09Z TO 15Z TIME FRAME FROM W TO E. UNFORTUNATELY... 
SKEPTICISM REMAINS. UNTIL THE PRECIP ACTUALLY DEVELOPS AND FILLS 
IN...CONFIDENCE IS NOT HIGH ENOUGH TO INCLUDE THE SHOWERS AS MORE 
THAN A TEMPO GROUP. WILL ALSO NOT INCLUDE ANY IFR RESTRICTIONS FOR 
THE SAME REASON. THE FRONTAL ZONE WILL MOVE ACROSS THE REGION DURING 
THE LATE MORNING AND EARLY AFTERNOON AND WILL BRING A WIND SHIFT TO 
W AND THEN WNW BY MID AFTERNOON...WITH CONDITIONS BECOMING VFR ONCE 
AGAIN. ALL SITES SHOULD HAVE ONLY SCATTERED CIRRUS FOR THE REST OF 
THE PERIOD WITH WIND REMAINING NW THRU THE EVENING. WIND MAY GO 
LIGHT NW OR PERHAPS CALM TOWARD THE END OF THE PERIOD...BUT THOSE 
DETAILS WERE OMITTED FOR BREVITY.
 
OUTLOOK...VFR FROM EARLY TUESDAY MORNING THROUGH WEDNESDAY. AN 
APPROACHING WARM FRONT AND RESULTANT MOISTURE RETURN WILL BRING 
BETTER CHANCES FOR PRECIP/RESTRICTIONS ACROSS THE AREA LATER IN THE 
WEEK...PERHAPS STARTING THURSDAY MORNING. EVENTUALLY...A SLOW MOVING 
COLD FRONT WILL AFFECT THE AREA FRIDAY OR SATURDAY WITH MORE 
RESTRICTIONS.

CONFIDENCE TABLE...

            07-13Z        13-19Z        19-01Z        01-06Z 
KCLT       HIGH 100%     HIGH  84%     HIGH 100%     HIGH 100%     
KGSP       HIGH 100%     MED   73%     HIGH 100%     HIGH 100%     
KAVL       HIGH  92%     HIGH  82%     HIGH 100%     HIGH 100%     
KHKY       HIGH 100%     MED   78%     HIGH 100%     HIGH 100%     
KGMU       HIGH 100%     MED   73%     HIGH 100%     HIGH 100%     
KAND       HIGH 100%     MED   78%     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...CDG
NEAR TERM...PM
SHORT TERM...CDG
LONG TERM...CDG
AVIATION...PM

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