434  
FXUS62 KGSP 142352  
AFDGSP  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC  
752 PM EDT WED APR 14 2021  
   
SYNOPSIS
 
 
CONTINUED THREAT OF SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS  
LATE THIS AFTERNOON INTO TONIGHT AS A RELATIVELY DRY COLD FRONT  
PASSES THROUGH WITH MUCH COOLER AND DRIER AIR BEHIND IT TO WRAP UP  
THE WORK WEEK. UNSETTLED WEATHER MAY RETURN THIS WEEKEND AS BETTER  
MOISTURE PUSHES IN FRIDAY NIGHT.  
 

 
   
NEAR TERM /THROUGH THURSDAY/
 
 
AS OF 743 PM EDT WEDNESDAY: SOME PATCHES OF LIGHT RAIN WERE MOVING  
EAST ACROSS THE MTNS AND UPSTATE, BUT MOST LOCATIONS WERE PROBABLY  
ONLY GETTING LITTLE MORE THAN SPRINKLES. THIS TREND SHOULD CONTINUE  
AS THE FRONT MOVES IN FROM THE WEST, SO THE PASSAGE OF THE FRONT  
LOOKS TO BE UNIMPRESSIVE. A FEW CHANGES WERE MADE TO PRECIP PROBS  
TO ACCOUNT FOR THE MODEL/RADAR TRENDS. AT THIS POINT, ONLY A  
SMALL AREA NORTH OF I-40 AND EAST OF THE MTNS HAS ANY CHANCE FOR  
A THUNDERSTORM.  
 
OTHERWISE...MOST OF THE SHOWER ACTIVITY WITH THE PASSING UPPER WAVE  
WILL MOVE EAST OF THE FORECAST AREA BY MIDNIGHT TONIGHT. HOWEVER,  
LOWER-LEVEL MOISTURE WILL INCREASE POST-FROPA, WITH RESIDUAL  
WESTERLY FLOW UPSLOPE SHOWERS LIKELY NEAR THE SPINE OF THE SOUTHERN  
APPALACHIANS OVERNIGHT. AFTER SOME MORNING LINGERING CLOUDS,  
POST-FROPA DRYING WILL WORK IN FROM THE WEST ON THURSDAY. DESPITE  
MODEST DOWNSLOPE FLOW EAST OF THE MOUNTAINS, TEMPERATURES SHOULD  
BE ABOUT 10 DEGREES COOLER THURSDAY AFTERNOON GIVEN THE FALLING  
THICKNESSES WITH THE FROPA. EXPECT BREEZY CONDITIONS WITH MIXING  
AS WELL.  
 

 
   
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/
 
 
AS OF 215 PM WEDNESDAY: CANADIAN HIGH PRESSURE BUILDS IN BEHIND THE  
DEPARTING FROPA THURSDAY NIGHT INTO FRIDAY LEADING TO DRIER WEATHER  
ACROSS THE REGION WHILE A LOW PRESSURE SYSTEM TO OUR NORTH TRACKS  
EAST ACROSS THE NORTHEASTERN CONUS. BREEZY WINDS WILL CONTINUE  
THURSDAY EVENING INTO THE OVERNIGHT HOURS WITH THE HIGHEST GUSTS  
OCCURRING IN THE MOUNTAINS. PATCHY FROST REMAINS POSSIBLE ACROSS THE  
NC MTNS EARLY FRIDAY MORNING DUE TO LOWS DROPPING INTO THE MID TO  
UPPER 30S. SOME LOCATIONS COULD SEE SLIGHTY LOWER TEMPS RANGING FROM  
THE UPPER 20S TO LOWER 30S. IT IS IMPORTANT TO NOTE THAT LOW  
DEWPOINTS ALONG WITH INCREASING CLOUD COVER AND BREEZY WINDS COULD  
LIMIT FROST FORMATION. LOWS ELSEWHERE FRIDAY MORNING SHOULD RANGE  
FROM THE UPPER 30S TO MID 40S. THE MAIN STORY FOR FRIDAY WILL BE  
CONCERNS FOR FIRE WX AS RH VALUES IN MOST LOCATIONS WILL BE IN THE  
MID TO UPPER 20S. WINDS SHOULD REMAIN FAIRLY BREEZY FRIDAY MORNING,  
HOWEVER THEY SHOULD GRADUALLY RELAX THROUGHOUT THE DAY. HIGH TEMPS  
FRIDAY SHOULD BE A FEW DEGREES BELOW CLIMATOLOGY.  
 
SATURDAY A WARM FRONT WILL BE OVER THE FLORIDA PANHANDLE WHILE AN  
AREA OF LOW PRESSURE TRACKS EASTWARD ACROSS THE MIDWEST. THESE TWO  
SYSTEMS WILL INTERACT WITH EACH OTHER LEADING TO AN INCREASE IN RAIN  
CHANCES ACROSS THE FORECAST AREA. BOTH INSTABILITY AND MOISTURE LOOK  
LIMITED AGAIN WITH THIS EVENT. MODELS ARE NOT IN GOOD AGREEMENT IN  
REGARDS TO THE OVERALL COVERAGE OF RAIN ACROSS THE CWA; HOWEVER, THE  
MAJORITY OF MODELS SHOW POPS OCCURRING OVER THE REGION WITH THE  
EXCEPTION OF THE CANADIAN WHICH LOOKS TO BE THE OUTLIER. HIGHS ON  
SATURDAY WILL BE ROUGHLY 6 TO 8 DEGREES BELOW CLIMATOLOGY.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
 
 
AS OF 2PM EDT WEDNESDAY: EXTENDED FORECAST IS MOSTLY DRY AND A  
LITTLE ON THE COOL SIDE FOR THIS TIME OF YEAR. BROAD LONG WAVE  
UPPER PATTERN HAS A MEAN TROUGH OVER THE EASTERN CONUS SATURDAY  
NIGHT THAT GENERALLY DEEPENS THROUGH MID-WEEK, INTERRUPTED BY  
OCCASIONAL EMBEDDED SHORTWAVES AND ASSOCIATED WEAK FRONTAL PASSAGES.  
MOISTURE NEVER RECOVERS VERY MUCH AND CHANCES FOR ANY SIGNIFICANT  
PRECIPITATION ARE LOW. BEST CHANCES FOR RAIN APPEARS TO BE SUNDAY  
OR MONDAY (DEPENDING ON WHICH MODEL IS CONSULTED) AS A FAIRLY POTENT  
SHORTWAVE CROSSES THE SOUTHERN APPALACHIA, WITH LITTLE MOISTURE TO  
WORK WITH, AND NO CONVECTIVE INSTABILITY. WINDS WILL GENERALLY BE  
LIGHT THROUGH THE EXTENDED AS WELL, AND MORE GENERALLY LIGHT  
NORTHERLY TO NORTHWESTERLY.  
 

 
   
AVIATION /00Z THURSDAY THROUGH MONDAY/
 
 
AT KCLT AND ELSEWHERE: VFR AT ALL TERMINALS THROUGH THE  
PERIOD. LIGHT PRECIP MOVING IN FROM THE WEST MAY AFFECT ALL  
SITES THROUGH THE MID/LATE EVENING, BUT WITH LITTLE CHANCE OF A  
VISIBILITY OR CEILING RESTRICTION. INSTEAD, A MID-LEVEL CEILING IS  
EXPECTED. WIND WILL BE SW OR SSW UNTIL THE BOUNDARY PASSES LATE THIS  
EVENING AND THE WIND COMES AROUND TO W OR WNW. THE MID-LEVEL CLOUDS  
WILL PERSIST INTO THURSDAY BEFORE DRYING OCCURS AND THE CLOUD DECK  
MOVES EAST. ONCE THAT HAPPENS, IN THE MIDDLE PART OF THE AFTERNOON,  
WE SHOULD SEE OCCASIONAL WIND GUSTS AS MIXING BECOMES DEEP ENOUGH TO  
TAP INTO STRONGER WINDS ALOFT. SKY SHOULD CLEAR LATE IN THE PERIOD.  
 
OUTLOOK: DRY/VFR CONDITIONS CONTINUE INTO FRIDAY NIGHT. A LOW  
PRESSURE SYSTEM PASSING SOUTH OF THE AREA COULD BRING A ROUND OF  
PRECIPITATION AND RESTRICTIONS OVER THE WEEKEND, BUT CONFIDENCE  
IN THIS SCENARIO IS VERY LOW AT THIS TIME, WITH LOW CONFIDENCE  
CONTINUING INTO EARLY NEXT WEEK.  
 
CONFIDENCE TABLE...  
 
00-06Z 06-12Z 12-18Z 18-00Z  
KCLT HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KGSP HIGH 100% HIGH 100% HIGH 100% HIGH 100%  
KAVL HIGH 96% HIGH 93% 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 99% 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 ARE AVAILABLE AT  
THE FOLLOWING LINK:  
 
WWW.WEATHER.GOV/GSP/AVIATION  
 

 
   
FIRE WEATHER
 
 
WITH DEWPOINT MIXING OCCURRING THIS AFTERNOON, THE RH MAY BRIEFLY  
TOUCH 25% IN A FEW LOCATIONS LATE THIS AFTERNOON. IN ADDITION,  
MIXING WILL PERMIT GUSTS IN THE UPPER TEENS TO NEAR 20 MPH TO  
DEVELOP AT TIMES. DRY AND BREEZY CONDITIONS WILL CONTINUE THURSDAY  
AND FRIDAY. CONDITIONS SHOULD REMAIN JUST SHORT OF FIRE DANGER OR  
RED FLAG LEVELS.  
 

 
   
EQUIPMENT
 
 
THE RADAR AT WFO GSP IS CURRENTLY DOWN DUE TO EQUIPMENT FAILURE.  
TECHNICIANS ARE WORKING ON THE ISSUE BUT PARTS MAY NEED TO BE  
ORDERED AND THE RADAR MAY REMAIN DOWN FOR 1 TO 3 DAYS.  
 

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

 
 

 
SYNOPSIS...MPR  
NEAR TERM...HG/PM  
SHORT TERM...AP  
LONG TERM...WJM  
AVIATION...PM  
FIRE WEATHER...  
EQUIPMENT...  
 
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