231  
FXUS62 KGSP 232256  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
556 PM EST TUE JAN 23 2018  
   
SYNOPSIS
 
 
DRY HIGH PRESSURE WILL OVERSPREAD THE REGION AND PERSIST INTO THE  
END OF THE WORK WEEK. ANOTHER COLD FRONT WILL BRING RAIN TO THE  
REGION OVER THE WEEKEND, WITH DRYING EXPECTED NEXT WEEK.  
 

 
   
NEAR TERM /THROUGH WEDNESDAY/
 
 
AS OF 530 PM EST...ALL IS QUIET ACROSS THE WESTERN CAROLINAS AND  
NORTHEAST GA. NO CHANGES NEEDED.  
 
OTHERWISE...AN UPPER TROUGH WILL CONTINUE TO LIFT ACROSS THE  
EASTERN GREAT LAKES TO THE ST. LAWRENCE VALLEY TONIGHT, PUSHING  
A COLD FRONT FURTHER EAST OF THE AREA. LOW-LEVEL FLOW IS STARTING  
OUT SWLY BEHIND THE FRONT, BUT SHOULD GRADUALLY VEER TO NWLY THRU  
THIS EVENING. AS IT DOES, SFC WINDS SHOULD DIMINISH SOMEWHAT  
AND LOSE THE STRONG GUSTS OUTSIDE THE MOUNTAINS, BUT ACTUALLY  
PICK UP A BIT IN THE HIGH TERRAIN. THE CURRENT WIND ADVISORY FOR  
THE NORTHERN MOUNTAINS THRU 15Z WED LOOKS GOOD. THE NW FLOW WILL  
ALSO BRING A CLOUD DECK UP AGAINST THE TN/NC BORDER AREAS, WITH  
A FEW SNOW SHOWERS POSSIBLE. SNOW ACCUMS SHOULD BE VERY LIGHT,  
GENERALLY A DUSTING TO UP TO HALF AN INCH. OTHER THAT THOSE LOW  
CLOUDS, ONLY A FEW WISPS OF CIRRUS ARE EXPECTED OVERNIGHT. TEMPS  
WILL RETURN TO NEAR NORMAL WITH LOWS IN THE 20S IN THE MTNS AND  
LOWER TO MID-30S ACROSS THE PIEDMONT.  
 
WEDNESDAY, SFC HIGH PRESSURE WILL BUILD IN FROM THE WEST AND SHOULD  
BRING IN DRIER AND DISSIPATE THE NW FLOW CLOUDS AND SNOW SHOWERS  
BY EARLY AFTN. WINDS SHOULD BE MUCH LIGHTER, ESPECIALLY EAST OF THE  
MTNS. UNDER SUNNY TO MOSTLY SUNNY SKIES, HIGHS WILL BE A CATEGORY OR  
TWO BELOW NORMAL IN THE MTNS AND NEAR NORMAL IN THE PIEDMONT. HIGHS  
MAINLY IN THE 40S MTNS AND LOWER TO MID-50S PIEDMONT.  
 

 
   
SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/
 
 
AS OF 155 PM EST TUESDAY: HEIGHTS RISE THROUGH THE PERIOD AS A SHORT  
WAVE MOVES EAST OF THE AREA WEDNESDAY NIGHT AND A RIDGE AXIS BUILDS  
IN BY FRIDAY. THE LAST OF THE BREEZY CONDITIONS AND NW UPSLOPE FLOW  
CLOUDS ACROSS THE MOUNTAINS COME TO AN END WEDNESDAY NIGHT AS HIGH  
PRESSURE BUILDS IN FROM THE WEST. THE CENTER OF THE HIGH MOVES  
ACROSS THE AREA THURSDAY THEN TO OUR EAST FRIDAY BUT HIGH PRESSURE  
REMAINS RIDGED INTO THE AREA FROM THE EAST. LOWS A LITTLE BELOW  
NORMAL WEDNESDAY NIGHT RISE TO AROUND NORMAL THURSDAY NIGHT. HIGHS A  
FEW DEGREES ABOVE NORMAL THURSDAY RISE TO AROUND 5 DEGREES ABOVE  
NORMAL FOR FRIDAY.  
 

 
   
LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/
 
 
AS OF 200 PM EST TUESDAY: THE MEDIUM RANGE FORECAST PICKS UP FRIDAY  
NIGHT WITH THE AREA UNDER THE WANING INFLUENCE OF A SURFACE HIGH  
CENTERED OFF THE EAST COAST NEAR BERMUDA. SURFACE WINDS WILL VEER  
AROUND FROM THE SOUTHEAST AHEAD OF AN APPROACHING UPPER TROUGH AND  
SURFACE COLD FRONT, GRADUALLY MOISTENING THE ATMOSPHERIC COLUMN. ON  
SATURDAY, GUIDANCE DISAGREES SOMEWHAT ON THE ONSET OF PRECIPITATION,  
THOUGH SOME LIGHT RAIN IN THE NORMAL FAVORED UPSLOPE AREAS NEAR THE  
BLUE RIDGE ESCARPMENT APPEARS LIKELY AT THIS POINT, WITH ISOLATED  
PRECIP IN ALL OTHER LOCATIONS IN THE FORECAST AREA BECOMING MORE  
LIKELY AS SATURDAY WEARS ON. THE BULK OF THE PRE-FRONTAL PRECIP WILL  
ARRIVE ON SUNDAY, WITH WIDESPREAD SHOWERS EXPECTED ACROSS THE ENTIRE  
AREA. FORCING AND SHEAR WILL BE QUITE GOOD ON SUNDAY AFTERNOON, BUT  
INSTABILITY, ESPECIALLY SURFACE-BASED INSTABILITY, WILL BE VERY  
LIMITED. NONETHELESS, THE FRONT AND UPPER TROUGH WILL BE DYNAMIC  
ENOUGH THAT THIS PORTION OF THE FORECAST SHOULD BE WATCHED CLOSELY  
OVER THE NEXT FEW DAYS. THERE IS STILL SOME DISAGREEMENT OF THE  
EXACT EVOLUTION OF THE SURFACE FRONT AND THE POTENTIAL FOR THE  
DEVELOPMENT OF A GULF LOW ON SUNDAY, SO QPF IS STILL IN QUESTION,  
THOUGH NO MAJOR GLOBAL MODEL HAS PARTICULARLY THREATENING WEEKEND  
RAINFALL TOTALS AT THE MOMENT.  
 
GUIDANCE REMAINS IN DISAGREEMENT ON THE SPEED OF THE FRONT AS WELL,  
THOUGH MAJOR MODELS DO AGREE THAT PRECIP WILL COME TO AN END BY 12Z  
MONDAY MORNING, WITH THE EXCEPTION OF SOME LIGHT LINGERING NW FLOW  
SNOW. TEMPERATURES WILL BE ALMOST 10 DEGREES ABOVE AVERAGE AHEAD OF  
THE FRONT ON SUNDAY BEFORE DROPPING TO NEAR AVERAGE MONDAY THROUGH  
THE REST OF THE PERIOD AFTER THE FRONTAL PASSAGE.  
 

 
   
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
 
 
AT CLT AND ELSEWHERE, EXCEPT KAVL...VFR CONDITIONS EXPECTED THRU THE  
PERIOD, AS DRY HIGH PRESSURE BUILDS IN BEHIND A PASSING COLD FRONT.  
WINDS ARE STILL QUITE GUSTY OUT OF THE SW AND WILL CONTINUE UNTIL  
AROUND SUNSET, THEN SHOULD DIMINISH AND LOSE GUSTINESS.  
 
AT KAVL...SAME AS ABOVE, EXCEPT WINDS WILL BE OUT OF THE NW THRU THE  
PERIOD AND REMAIN GUSTY. THERE IS ALSO A CHANCE THAT SOME LOW-VFR OR  
POSSIBLY MVFR STRATUS WORKS UP THE VALLEY OVERNIGHT, AS FLOW TURNS  
OUT OF THE NW. FOR NOW, WILL HIGHLIGHT SOME SCT040 DURING THE  
OVERNIGHT HOURS.  
 
OUTLOOK: DRY HIGH PRESSURE WILL DOMINATE THE AREA THROUGH THE  
REMAINDER OF THE WEEK. ANOTHER SYSTEM WILL MOVE IN OVER THE WEEKEND,  
BRINGING ANOTHER ROUND OF -SHRA AND RESTRICTIONS.  
 
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 95% 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:  
 
WWW.WEATHER.GOV/GSP/AVIATION  
 

 
   
GSP WATCHES/WARNINGS/ADVISORIES
 
 
GA...NONE.  
NC...WIND ADVISORY UNTIL 10 AM EST WEDNESDAY FOR NCZ033-049-050.  
SC...NONE.  
 

 
 

 
SYNOPSIS...CARROLL  
NEAR TERM...ARK/PM  
SHORT TERM...RWH  
LONG TERM...CARROLL  
AVIATION...ARK  
 
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