913  
FXUS62 KGSP 032025  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
325 PM EST SAT DEC 3 2016  
   
SYNOPSIS
 
 
INCREASED MOISTURE WILL RETURN FROM THE WEST ON SUNDAY AND LINGER  
INTO TUESDAY. A STRONG COLD FRONT WILL ARRIVE EARLY THURSDAY  
BRINGING SOME OF THE COLDEST AIR OF THE SEASON SO FAR AT THE  
END OF THE WEEK.  
 

 
   
NEAR TERM /THROUGH SUNDAY/
 
 
AS OF 130 PM EST SATURDAY: A CLOSED H5 CYCLONE CENTERED OVER NW  
MEXICO CONTINUES TO DEEPEN AS MOISTURE LIFTS N/NE ACROSS THE MS  
DELTA REGION INTO THE THE TN/OH VALLEYS. SURFACE HIGH PRESSURE  
REMAINS CENTERED OVER THE SOUTHERN/CENTRAL APPALACHIANS THIS  
AFTERNOON AND THUS REINFORCING A DRY LLV AIRMASS. HOWEVER, GIVEN  
THE AFOREMENTIONED MOISTURE ADVECTION AND SWLY FLOW ALOFT, THE ATM  
WILL MOISTEN WITH TIME FROM THE TOP DOWN. AS SUCH, LATEST VISSAT  
IMAGERY INDICATES MODEST AMOUNTS OF MID/HIGH ALTOCU/CIRRUS STREAMING  
INTO NORTHEAST GA AND THE SOUTHERN APPALACHIANS AT PRESENT TIME.  
THIS PATTERN WILL CONTINUE INTO THE EVENING/OVERNIGHT WITH POPS  
INCREASING LATER THIS AFTERNOON FROM THE WEST WITH LIKELY LEVELS  
FAVORED WEST OF I77 BY 12Z, THEN SPREADING ACROSS THE ENTIRE FCST  
AREA BY MIDDAY SUNDAY.  
 
PROFILES ACROSS THE REGION DURING THIS TIME FRAME SO SUPPORT ALL  
RA WITH THE EXCEPTION OF HIGHER TERRAIN LOCALES ABOVE 4-5KFT.  
FOR THOSE AREAS, EXPECTING PTYPE PHASE CHANGES FROM RA BY EARLY  
MORNING TO RA/SN OR ALL SN BY MID/LATE MORNING, ESPECIALLY ACROSS  
THE NORTHERN MTNS. SOME LIGHT ACCUMULATIONS ARE POSSIBLE IN THIS  
REGION, HOWEVER GENERALLY LESS THAN 1 INCH. TEMPERATURES WILL  
SLOWLY WARM INTO LATE MORNING ACROSS THE ENTIRE FCST AREA LEADING  
TO ALL RA BY MIDDAY AS HIGHS TOP OUT IN THE UPPER 30S ACROSS THE  
MTNS TO UPPER 40S OVER THE PIEDMONT. RAINFALL AMOUNTS THROUGH  
SUNDAY AFTERNOON ARE FCST TO BE AROUND 1-1.25 INCHES ACROSS  
THE SOUTHWEST/CENTRAL NC MTNS AND NORTHEAST GA, TAPERING DOWN  
TO THE EAST WITH A HALF TO QUARTER INCH FAVORED AT GSP AND CLT  
RESPECTIVELY.  
 

 
   
SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/
 
 
AS OF 215 PM EST SATURDAY: A SPLIT FLOW PATTERN EARLY IN THE PERIOD  
EVOLVES INTO A SINGLE FLOW ATLANTIC RIDGE AND BROAD CENTRAL AND  
WESTERN CONUS TROUGH BY THE END OF THE PERIOD. THE NORTHERN WAVE OF  
THE SPLIT FLOW ON PUSHES A FRONTAL BOUNDARY ACROSS THE AREA. THE  
COMBINATION OF DEEP MOISTURE AND SYNOPTIC SCALE LIFT, ALONG WITH  
ISENTROPIC LIFT, WILL SPREAD RAIN ACROSS THE AREA THROUGH THE NIGHT.  
ALTHOUGH SURFACE TEMPS ACROSS THE NORTHERN MOUNTAINS WILL BE IN THE  
MID 30S OVERNIGHT, A NEARLY 10 DEGREE C LOW LEVEL WARM NOSE WILL  
KEEP PRECIP AS ALL LIQUID. LOWS WILL BE AROUND 5 DEGREES BELOW  
NORMAL. QPF VALUES WILL RANGE FROM TENTH TO A HALF AN INCH FROM  
NORTH TO SOUTH.  
 
THE MOISTURE AND LIFT MOVE EAST AND SOUTH OF THE AREA EARLY MONDAY  
AS HIGH PRESSURE BUILDS IN FROM THE NORTH AND SETS UP IN A COLD AIR  
DAMMING PATTERN. AS THIS TAKES PLACE, THE SOUTHERN STREAM UPPER LOW  
OVER THE RIO GRANDE OPENS UP AND MOVES ACROSS TEXAS. SHORT WAVE  
ENERGY MOVES THROUGH THE FLOW AHEAD OF THE LOW AND ACROSS OUR AREA.  
THE ASSOCIATED SURFACE LOW MOVES EAST ALONG THE GULF COAST SPREADING  
A MOIST SOUTHERLY FLOW ACROSS THE SE CONUS. PRECIP SPREADS BACK INTO  
THE AREA FROM THE SW IN RESPONSE. QPF WILL BE LIGHT. TEMPS WILL BE  
TRICKY WITH THE DAMMING HIGH SETTING UP, BUT PRECIP TAPERING OFF  
ACROSS PORTIONS OF THE AREA. EXPECT HIGHS GENERALLY IN THE LOW TO  
MID 50S, BUT THEY COULD BE HIGHER WHERE PRECIP ENDS AND LOWER WHERE  
IT LINGERS.  
 
PRECIP DEVELOPS IN EARNEST MONDAY NIGHT AS THE UPPER LOW TRACKS INTO  
MS AND THE SURFACE LOW TAKES ON A MILLER B PATTERN. DEEP MOISTURE  
RETURNS, ALONG WITH STRONG SYNOPTIC AND ISENTROPIC FORCING. THIS  
WILL STRENGTHEN THE DAMMING HIGH ACROSS THE AREA. AS THE SURFACE  
LOWS TRACK EAST ON TUESDAY, THE SOUTHERN WEDGE BOUNDARY DOES LIFT  
NORTH TOWARD THE AREA. HOWEVER, EXPECT IT, AND ANY RESULTING  
INSTABILITY OR THUNDERSTORMS, TO REMAIN TO OUR SOUTH AS WELL. STILL,  
GIVEN THE PW VALUES AND STRENGTH OF THE FORCING, EXPECT QPF VALUES  
TO RANGE FROM AROUND 0.75 INCHES NEAR THE TN BORDER TO 1.5 INCHES  
ALONG THE SOUTHERN TIER OF THE CWFA. LOWS MONDAY NIGHT WILL BE  
AROUND 10 DEGREES ABOVE NORMAL WITH ALL LIQUID PRECIP. HIGHS WILL BE  
NEAR NORMAL ACROSS THE MOUNTAINS WHERE THE DAMMING INFLUENCE IS  
LESS, TO AROUND 5 DEGREES BELOW NORMAL ELSEWHERE.  
 

 
   
LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
 
 
AS OF 245 PM EST SATURDAY: A SURFACE BOUNDARY SHOULD BE SOUTH OF OUR  
COUNTY WARNING AREA (CWA) TUESDAY EVENING AS A DEAMPLIFYING UPPER  
LEVEL TROUGH AND VORT MAX QUICKLY SWEEP NORTHEAST INTO VIRGINIA.  
THIS WILL ALLOW ANY LINGERING POPS TO END QUICKLY IN THE EVENING.  
 
WEDNESDAY A RATHER NON DESCRIPT PATTERN AS THE ATMOSPHERE RELOADS TO  
THE WEST, AND THE SURFACE PATTERN ACROSS OUR REGION REMAINS "BAGGY"  
WITH A WEAK FLOW. CONDITIONS SHOULD REMAIN DRY FOR THE BALANCE OF  
THE DAY.  
 
A STRONG H5 TROUGH WILL ROTATE INTO THE MIDDLE OHIO VALLEY WEDNESDAY  
NIGHT AND THURSDAY, SIGNALING A CHANGE IN OUR WEATHER PATTERN. THIS  
WILL ALLOW A SHOT OF COLD AIR TO BEGIN A PLUNGE INTO THE REGION.  
THERMAL STRUCTURE CONTINUES TO SHOW A DOWNWARD TREND IN THICKNESS  
AND H85 TEMPERATURES FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY -  
AT LEAST.  
 
WE WILL CONTINUE WITH LOW POPS FROM LATE WEDNESDAY NIGHT INTO THE  
WEE HOURS THURSDAY NIGHT - WITH WEAK VORTICITY ADVECTION/COLD AIR  
ADVECTION AND A BIT OF MOISTURE. DEEPEST MOISTURE SHOULD BE IN OUR  
NORTH CAROLINA MOUNTAINS. SPEAKING OF OUR NORTH CAROLINA MOUNTAINS  
IT APPEARS TO BE COLD ENOUGH FOR A CHANGE TO ALL SNOW SHOWERS,  
ALTHOUGH PRECIPITATION AMOUNTS SHOULD BE LIGHT AT THE MOMENT.  
 
COLD HIGH PRESSURE WILL THEN BUILD INTO THE REGION FRIDAY AND  
SATURDAY.  
 
TEMPERATURES AROUND NORMAL WEDNESDAY WILL START A MUCH COLDER TREND  
IN THE THURSDAY THROUGH SATURDAY TIME RANGE, PERHAPS SOME 10 TO 15  
DEGREES BELOW NORMAL.  
 

 
   
AVIATION /21Z SATURDAY THROUGH THURSDAY/
 
 
AT KCLT AND ELSEWHERE: A MIXTURE OF VFR/MVFR AND POSSIBLY IFR IS  
EXPECTED THROUGH THIS TAF CYCLE AS MOISTURE ADVECTS INTO THE REGION  
FROM THE SOUTHWEST. A DEEPENING SYSTEM MOVING THROUGH NORTHERN  
MEXICO WILL CONTINUE TO LOFT MOISTURE NE OVER THE SOUTHERN STATES  
THROUGH THE PERIOD. AS SUCH, AM EXPECTING SAID MOISTURE TO LIFT  
ISENTROPICALLY ATOP A BROAD REGION OF HIGH PRESSURE. THIS WILL  
RESULT IN INCREASED CHANCES FOR RA INTO/THRU THE OVERNIGHT WITH  
CIGS/VISB FALLING INTO RESTRICTIVE FLIGHT CATEGORIES. THESE  
RESTRICTION LEVELS AND TIMING IN THE TAFS ARE BASED UPON LATEST  
CAM GUIDANCE AND FCST SOUNDINGS. ONCE CONDITIONS DETERIORATE,  
RESTRICTIONS ARE FAVORED AT ALL SITES THROUGH THE PERIOD.  
WINDS WILL REMAIN LIGHT VRB THIS AFTERNOON, POSSIBLY VEERING SELY  
AT THE PIEDMONT SITES TO INCLUDE KCLT, THEN SHOULD BACK NLY FOR  
THE REMAINDER OF THE TAF CYCLE.  
 
OUTLOOK: MOISTURE WILL GRADUALLY SPREAD INTO THE REGION THROUGH  
SUNDAY LEADING TO INCREASING CHANCES FOR PRECIPITATION AND  
RESTRICTIONS. A BRIEF LULL IS POSSIBLE MONDAY WITH THE BEST CHANCE  
FOR HEAVIER RAIN AND WIDESPREAD RESTRICTIONS ON TUESDAY. BRIEF DRY  
WEATHER ON WEDNESDAY, WITH ANOTHER FRONT APPROACHING FROM THE WEST.  
 
CONFIDENCE TABLE...  
 
20-02Z 02-08Z 08-14Z 14-18Z  
KCLT HIGH 100% HIGH 100% HIGH 83% HIGH 93%  
KGSP HIGH 100% HIGH 100% HIGH 88% HIGH 98%  
KAVL HIGH 100% HIGH 100% HIGH 89% HIGH 85%  
KHKY HIGH 100% HIGH 100% HIGH 90% HIGH 90%  
KGMU HIGH 100% HIGH 100% HIGH 87% HIGH 98%  
KAND HIGH 100% HIGH 95% HIGH 86% HIGH 97%  
 
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:  
 
WWW.WEATHER.GOV/GSP/AVIATION  
 

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

 
 

 
SYNOPSIS...SBK  
NEAR TERM...CDG  
SHORT TERM...RWH  
LONG TERM...TS  
AVIATION...CDG  
 
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