150  
FXUS62 KGSP 230243  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
943 PM EST WED NOV 22 2017  
   
SYNOPSIS
 
 
IN GENERAL, DRY HIGH PRESSURE WILL PERSIST OVER THE AREA THROUGH  
EARLY NEXT WEEK. A COUPLE OF COLD FRONTS WILL PASS THE AREA  
WITHOUT ENOUGH MOISTURE FOR PRECIPITATION. TEMPERATURES WILL  
REMAIN SEASONABLE.  
 

 
   
NEAR TERM /THROUGH THURSDAY/
 
 
AS OF 9:35 PM EST WEDNESDAY: WEATHER SHOULD BE NEARLY IDEAL FOR  
THANKSGIVING DAY. FRONT THAT PASSED-THROUGH ON TUESDAY IS NOW WELL  
SOUTHEAST OF THE AREA, LEAVING NORTHEASTERLY FLOW AND DRY ADVECTION  
BEHIND IT. A BIT OF AN UPPER TROUGH DIGS INTO THE DEEP SOUTH ON  
THURSDAY, BUT WILL HAVE LITTLE MOISTURE TO WORK WITH AT LOW-LEVELS,  
AND SURFACE LOW ASSOCIATED WITH IT WILL REMAIN WELL SOUTH OF THE  
AREA. SOME HIGH CLOUDS LOOK TO BE THE ONLY IMPACT FROM THIS TROUGH.  
A LARGE SURFACE HIGH PRESSURE AREA WILL BECOME CENTERED ALONG THE  
MOUNTAINS BY THURSDAY MORNING. WINDS THROUGH THURSDAY WILL THUS BE  
MUCH LIGHTER AND SOMEWHAT VARIABLE. THE LIGHT WINDS AND VERY DRY  
NEAR-SURFACE AIR SHOULD ALLOW FOR A LARGE DIURNAL RANGE, WITH THU  
MORNING'S MIN TEMPS LIKELY BOTTOMING OUT ABOUT 5 DEGREES BELOW  
CLIMO, OR ROUGHLY 10 DEGREES COOLER THAN WED MORNING. THURSDAY WILL  
BE A DRY AND CRISP FALL DAY WITH TEMPERATURES SLIGHTLY ABOVE  
SEASONAL NORMAL.  
 
FOG THAT WAS SEEN THIS MORNING IS UNLIKELY ON THURSDAY AS BL DRYING  
HAS DROPPED DEWPOINTS 10 DEGREES OR SO.  
 

 
   
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/
 
 
AS OF 200 PM WEDNESDAY...WITH SFC HIGH PRESSURE ACROSS THE AREA  
THURSDAY NIGHT, LATEST GUIDANCE CONTINUES TO DEPICT THE DEVELOPMENT  
OF A SFC LOW IN THE GULF OF MEXICO WHICH IS PROGGED TO MOVE ACROSS  
NORTHERN FL AND HUG THE FL/GA/CAROLINA COAST THROUGHOUT THE DAY ON  
FRIDAY, PER THE GFS/ECMWF. WITH SPLIT FLOW, THIS TRACK WOULD ALLOW  
FOR NW FLOW ALOFT TO PERSIST ACROSS OUR FORECAST AS SEEN FROM FCST  
SOUNDINGS SUGGESTING PWATS TO REMAIN AT OR BELOW ONE HALF OF AN  
INCH. HOWEVER, THE LATEST NAM, WEST OF BOTH THE GFS AND ECMWF,  
CONTINUES TO TRACK THIS SYSTEM A BIT NORTHWARD AND INLAND UP THROUGH  
GA/SC. IF THIS TRACK WERE TO EVOLVE, FCST SOUNDINGS ARE HIGHLIGHTING  
PWATS AT OR JUST ABOVE ONE INCH. FOR THIS FORECAST PACKAGE, AM GOING  
TO STICK WITH THE DRIER TREND OF THE GFS/ECMWF. WITH NEARLY CLEAR  
SKIES OVERNIGHT THURSDAY, ANTICIPATE TEMPERATURES TO DIP INTO THE  
LOW TO MID 30'S BEFORE CLIMBING INTO THE UPPER 50'S TO AROUND 60  
DEGREES ON FRIDAY.  
 
EXPECT TEMPERATURES TO BE SLIGHTLY WARMER/NEAR-NORMAL FRIDAY NIGHT  
AS LIMITED MOISTURE ALLOWS FOR MID TO HIGH CLOUDS TO INCREASE AHEAD  
OF AN APPROACHING COLD FRONT. PER LATEST GUIDANCE, ANTICIPATE THE  
FRONT TO PUSH THROUGH THE AREA SATURDAY MORNING. WITH LIMITED  
AVAILABLE MOISTURE AND WEAK FORCING, HAVE KEPT PRECIPITATION OUT OF  
THE FORECAST ATTM. AS CLOUDS GRADUALLY DECREASE BEHIND THE FRONT AND  
FLOW ALOFT BECOMES NEARLY ZONAL, EXPECT TEMPERATURES ON SATURDAY TO  
CLIMB INTO THE LOWER 60'S, THOUGH COOLER ACROSS THE MOUNTAINS.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
 
 
AS OF 2:15 PM WEDNESDAY: AN UPPER LEVEL NORTHWESTERLY FLOW WILL BE  
IN PLACE SATURDAY NIGHT, FOLLOWING THE EARLIER SURFACE COLD FRONTAL  
PASSAGE. THIS WILL SIGNAL A TREND TOWARD COOLER TEMPERATURES ACROSS  
OUR FORECAST AREA (FA) FOR THE LATTER HALF OF THE WEEKEND. THE GFS  
DOES SHOW SOME VERY SHALLOW MOISTURE IN THE NORTHERN MOUNTAINS OF  
NORTH CAROLINA BRIEFLY ON SATURDAY NIGHT, BUT ITS DEPTH APPEARS TO  
SHALLOW FOR ANY PRECIPITATION.  
 
HIGH PRESSURE WILL MOVE FROM THE OHIO AND TENNESSEE VALLEYS SUNDAY,  
INTO OUR FA SUNDAY NIGHT AND MONDAY. ALOFT THE FLOW REMAINS DRY  
NORTHWESTERLY, ALTHOUGH EASING BY LATE MONDAY.  
 
THE SURFACE HIGH WILL CONTINUE MOVING SOUTH AND EAST OF THE REGION  
TUESDAY, WHILE THE FLOW ALOFT BACKS TO THE SOUTHWEST. THIS WILL  
SIGNAL THE START OF A WARMING TREND, BUT STILL DRY.  
 
IN THE LATTER PART OF THE FORECAST THE MODELS DIVERGE ON HOW FAST TO  
MOVE A COLD FRONT INTO OUR AREA WEDNESDAY. THE GFS WAS FAST, WHILE  
THE EUROPEAN WAS SLOWER. THE SLOWER EUROPEAN WAS BACKING AND CUTTING  
OFF PARTS OF THE UPPER LEVEL FLOW. THIS FAR OUT IN THE FORECAST  
SUGGESTS A COMPROMISE IS IN ORDER. WE WILL HAVE SOME LOW END POPS IN  
THE MOUNTAINS AND PART OF THE FOOTHILLS OF WESTERN NORTH CAROLINA,  
PARTS OF NORTHEAST GEORGIA, AND A SLIVER OF THE MOUNTAINS IN UPSTATE  
SOUTH CAROLINA WEDNESDAY.  
 
TEMPERATURES WEDNESDAY WILL BE TRICKY DEPENDING ON HOW FAST ANY MID  
WEEK FRONT ENTERS THE PICTURE.  
 

 
   
AVIATION /03Z THURSDAY THROUGH MONDAY/
 
 
AT KCLT AND ELSEWHERE: MUCH DRIER AIR WILL RESULT IN VFR CONDITIONS  
THROUGH THE PERIOD. CLOUDS SHOULD PRIMARILY BE LIMITED TO SCT-OVC  
HIGH CLOUDS OVER THE NEXT 18 HOURS OR SO, ALTHOUGH SOME STRATOCU IN  
THE 040-050 RANGE MAY DEVELOP NEAR THE UPSTATE SC TERMINALS THU  
MORNING, AS A SHALLOW LAYER OF LOWER LEVEL MOISTURE SNEAKS INTO THE  
AREA IN ASSOCIATION WITH AN AREA OF LOW PRESSURE DEVELOPING IN THE  
EASTERN GULF OF MEXICO. NE WINDS WILL CONTINUE TO GRADUALLY DIMINISH  
THROUGH THE EVENING, REMAINING LIGHT THROUGH THE END OF THE PERIOD.  
A SHIFT TO THE SE MAY OCCUR BY THE END OF THE PERIOD.  
 
OUTLOOK: EXPECT VFR THROUGH THE FORECAST PERIOD AS DRY/COOL  
CONDITIONS PREVAIL.  
 
CONFIDENCE TABLE...  
 
02-08Z 08-14Z 14-20Z 20-00Z  
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...DEO  
NEAR TERM...JDL/WJM  
SHORT TERM...SGL  
LONG TERM...TS  
AVIATION...JDL  
 
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