661  
FXUS62 KGSP 251856  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
256 PM EDT THU MAY 25 2017  
   
SYNOPSIS
 
 
A LARGE LOW PRESSURE SYSTEM WILL LIFT NORTHEAST OF THE AREA TONIGHT  
ALLOWING DRIER AIR TO OVERSPREAD THE REGION AND LINGER INTO EARLY  
SATURDAY. MOISTURE AND UNSTABLE CONDITIONS WILL RETURN TO THE REGION  
OVER THE WEEKEND, AHEAD OF A SLOW MOVING COLD FRONT.  
 

 
   
NEAR TERM /THROUGH FRIDAY/
 
 
AS OF 250 PM EDT THURSDAY: FOR THE REST OF THE AFTERNOON,  
CANNOT RULE OUT A FEW ADDITIONAL SHOWERS AND STORMS, MAINLY OVER  
THE WRN PIEDMONT OF THE CAROLINAS, AS COLD AIR ALOFT CONTINUES  
TO PROVIDE FOR SOME LIMITED SFC-BASED CAPE. SOME OF THE STRONGER  
CORES COULD HAVE SMALL HAIL, AS WE HAVE SEEN EARLIER. OTHER  
SHOWERY ELEMENTS MAY MOVE DOWN ACROSS THE NRN MTNS AND NRN  
FOOTHILLS AS THEY ROTATE AROUND THE UPPER LOW, SEEN IN THE WATER  
VAPOR IMAGERY MOVING INTO WV. TEMPS SHOULD REMAIN SEASONALLY  
COOL.  
 
OVER THE NEXT 24 HOURS, OUR WEATHER SHOULD CONTINUE TO UNWIND. THE  
UPPER LOW WILL MOVE PAST ACROSS THE MID-ATLANTIC REGION TONIGHT.  
ADDITIONAL LOW LEVEL MOISTURE AND SOME LIGHT PRECIP WILL COME DOWN  
ACROSS THE NORTHERN PART OF THE FCST AREA, WITH THE NW FLOW FORCING  
ADDITIONAL SHOWERS ALONG THE TN BORDER INTO THE EVENING HOURS. THE  
MODEL GUIDANCE SHOWS THIS GRADUALLY DRYING UP, WITH PRECIP ENDING BY  
AROUND MIDNIGHT. THERE IS SOME CONCERN FOR STRONG WIND GUSTS ACROSS  
THE HIGHER TERRAIN AS THE GUIDANCE SHOWS GREATER THAN 50KT FLOW AT  
850 MB COMING AROUND THE BOTTOM OF THE UPPER TROF TONIGHT. HOWEVER,  
THE BOUNDARY LAYER REMAINS SHALLOW, AND THEN DECOUPLES AND KEEPS  
THAT STRONGER FLOW FROM REACHING THE SFC IN MODEL FCST SOUNDINGS.  
LOW TEMPS WILL BE BELOW NORMAL TONIGHT, BUT NOT EXCEPTIONALLY COLD.  
ON FRIDAY, THE CYCLONIC FLOW ALOFT WILL GRADUALLY BE REPLACED BY A  
FLAT UPPER RIDGE BUILDING IN FROM THE WEST. THIS RIDGE WILL SUPPORT  
WEAK HIGH PRESSURE MOVING OVER THE SOUTHEAST. SUNNY SKY SHOULD  
PREVAIL THAT WILL RESULT IN A VERY NICE AND DRY LATE SPRING DAY WITH  
HIGH TEMPS JUST ABOVE NORMAL.  
 

 
   
SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/
 
 
AS OF 250 PM THU: ZONAL MID LEVEL FLOW WILL BE IN PLACE ACROSS  
THE REGION THROUGH THIS PERIOD. LOW LEVEL MOISTENING WILL BE  
OCCURRING ON FRIDAY NIGHT AND SATURDAY. A FRONTAL SYSTEM WILL  
MOVE INTO THE TENNESSEE VALLY ON SATURDAY ALLOWING SOME SHOWER  
AND THUNDERSTORM ACTIVITY TO MOVE INTO THE MOUNTAINS SATURDAY  
AFTERNOON AND SATURDAY NIGHT. ANOTHER ROUND OF STORMS SHOULD  
IMPACT MOST OF THE FORECAST AREA SUNDAY AFTERNOON.  
 
INSTABILITY WILL BE RATHER HIGH ON BOTH SATURDAY AND SUNDAY  
AFTERNOONS. SOME STORMS COULD BE RATHER STRONG ESPECIALLY IF THEY  
ARE ABLE TO ORGANIZE IN THE WESTERLY FLOW.  
 

 
   
LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/
 
 
AS OF 250 PM EDT THURSDAY: THE EXTENDED FCST PICKS UP AT 00Z ON  
MONDAY WITH FLAT UPPER RIDGING OVER THE SOUTHEAST AND ANOTHER  
BROAD UPPER TROF DIGGING DOWN OVER THE WESTERN GREAT LAKES. THE  
TROF IS SLOW TO MOVE EASTWARD AND IS NOT EXPECTED TO MOVE OVER  
THE FCST AREA UNTIL LATE TUES INTO EARLY WED. THE LONG RANGE  
MODELS HAVE THE TROF AXIS CENTERED TO OUR NORTH BY WED, HOWEVER  
MOST OF THE ENERGY ASSOCIATED WITH THE TROF REMAINS TO OUR  
NORTH. AS WE MOVE INTO THURSDAY, THE TROF LIFTS FARTHER NE AND  
HEIGHTS BEGIN TO RISE A BIT. AT THE SFC, A COLD FRONT WILL MOVE  
THRU THE CWFA ON MONDAY AND STALL OUT JUST TO OUR SE BY EARLY  
TUES. THE FRONT LINGERS OVER THE REGION UNTIL ANOTHER, MORE  
ROBUST COLD FRONT PUSHES THRU THE FCST AREA ON WED INTO EARLY  
THURS. AS FOR THE SENSIBLE FCST, NO SIGNIFICANT CHANGES WERE  
NECESSARY. WE STILL HAVE SOLID CHANCES FOR CONVECTION ON MONDAY,  
AND SLIGHT TO SOLID CHANCES ON TUESDAY THRU THURSDAY WITH THE  
HIGHEST POPS GENERALLY OVER THE HIGHER TERRAIN. TEMPS WILL START  
OUT JUST ABOVE CLIMATOLOGY AND COOL ON TUESDAY TO RIGHT AROUND  
NORMAL. THEY ARE EXPECTED TO REMAIN NEAR NORMAL FOR THE REST OF  
THE PERIOD.  
 

 
   
AVIATION /19Z THURSDAY THROUGH TUESDAY/
 
 
AT KCLT AND ELSEWHERE: VFR THROUGH THE PERIOD. SCT/BKN CLOUDS  
CONTINUE TO DEVELOP GENERALLY WITH BASES IN THE 040-050 RANGE AS  
COLDER AIR ALOFT MOVES OVERHEAD. THINK SCT WILL PREVAIL WITH  
TEMPORARY BKN CONDITIONS. A FEW SHOWERS MAY DEVELOP, MORE LIKELY  
OVER THE MTNS NEAR THE TN BORDER, AND OVER THE WRN PIEDMONT OF NC.  
HAVE INCLUDED A TEMPO AT KCLT FOR MVFR IN PASSING SHOWERS THROUGH  
22Z. THE CLOUDS SHOULD DIMINISH IN COVERAGE WITH LOSS OF HEATING,  
AND ANY REMAINING SHOWERS AFTER SUNSET SHOULD BE CONFINED TO THE TN  
BORDER AREA. WIND WILL REMAIN WSW WITH OCCASIONAL GUSTS THROUGH  
SUNSET, THEN DIMINISHING OVERNIGHT AS THE BOUNDARY LAYER DECOUPLES  
AND WEAK HIGH PRESSURE RIDGES UP FROM THE S. ON FRIDAY, ONLY SCT  
CIRRUS. WIND WILL BE SW OR WSW AGAIN OUTSIDE THE MTNS, WITH  
OCCASIONAL GUSTS BEGINNING MIDDAY AS THE BOUNDARY LAYER DEEPENS  
AGAIN WITH HEATING.  
 
OUTLOOK: CONTINUED VFR FRIDAY AFTERNOON AND NIGHT, AND INTO THE DAY  
ON SATURDAY. THUNDERSTORMS AND ASSOCIATED RESTRICTIONS MAY DEVELOP  
ACROSS NC SATURDAY AFTERNOON, BUT WILL BE MORE LIKELY SUNDAY.  
 
CONFIDENCE TABLE...  
 
19-01Z 01-07Z 07-13Z 13-18Z  
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:  
 
WWW.WEATHER.GOV/GSP/AVIATION  
 

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

 
 

 
SYNOPSIS...JPT  
NEAR TERM...PM  
SHORT TERM...SW  
LONG TERM...JPT  
AVIATION...PM  
 
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