360
FXUS62 KGSP 171843
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
243 PM EDT MON AUG 17 2026
WHAT HAS CHANGED
A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR THE MOUNTAINS AND
FOOTHILLS OF NORTH CAROLINAS AND NORTHEAST GEORGIA THROUGH 10 PM
THIS EVENING.
THE AVIATION FORECAST WAS UPDATED TO FOR 18Z TAF ISSUANCE.
KEY MESSAGES
1. ANOTHER HEAT ADVISORY IS IN EFFECT THROUGH THIS AFTERNOON FOR
THE SC UPSTATE, NORTHEAST GA, AND THE CHARLOTTE METRO. HOT AND
HUMID CONDITIONS PERSIST MOST OF THIS WEEK, WITH LITTLE RELIEF
UNTIL THIS WEEKEND.
2. SLIGHT RISK FOR SEVERE WEATHER ACROSS WESTERN NORTH CAROLINA
THIS EVENING. MORE SEASONALLY-TYPICAL DIURNAL CONVECTION CONTINUES
FOR MOST OF THE WEEK.
DISCUSSION
KEY MESSAGE 1: ANOTHER HEAT ADVISORY IS IN EFFECT THROUGH THIS
AFTERNOON FOR THE SC UPSTATE, NORTHEAST GA, AND THE CHARLOTTE
METRO. HOT AND HUMID CONDITIONS PERSIST MOST OF THIS WEEK, WITH
LITTLE RELIEF UNTIL THIS WEEKEND.
HOT AND MUGGY CONDITIONS CURRENTLY ONGOING WITH TEMPERATURES
GETTING WELL INTO THE MID AND UPPER 90S THIS AFTERNOON WITH
DEWPOINTS IN THE UPPER 60S AND LOW 70S. THE HEAT ADVISORY REMAINS
IN EFFECT FOR MUCH OF THE PIEDMONT ZONES SOUTH OF I-40. STARTING
TO SEE DEWPOINTS MIX OUT AS THE BOUNDARY LAYER CONTINUES TO DEEPEN
DURING PEAK HEATING, WITH A FEW LOCATIONS STILL REACH A HEAT INDEX
OF 105 DEGREES. DECIDED TO NOT DO A HEAT ADVISORY FOR TUESDAY AS
TEMPERATURES AND DEWPOINTS WILL BE SLIGHTLY LOWER COMPARED TO THE
PAST FEW DAYS.
BROAD SUBTROPICAL RIDGE WILL MEANDER OVER THE SOUTHERN CONUS OVER
THE NEXT FEW DAYS BEFORE THE CENTER OF THE RIDGE RETROGRADES TO
THE SOUTHWEST CONUS AND SUBTLE HEIGHT FALLS MOVE IN FROM THE
NORTHWEST OVER THE CWA. A DEEP CLOSED LOW WILL MOVE ACROSS THE
CENTRAL CANADIAN PROVIDENCES AND SET UP SHOP OVER THE HUDSON BAY
AND NORTHERN QUEBEC BY TUESDAY AND WEDNESDAY, WHICH WILL SEND
MULTIPLE ROUNDS OF SHORTWAVE TROUGHS ACROSS THE REGION STARTING
AROUND THURSDAY ONCE THIS FEATURE BECOMES MORE ESTABLISHED. THIS
WILL HELP BRING SMALL RELIEF TO THE REGION LATER THIS WEEK BEFORE
AN ACTUAL COLD FRONT MAKES ITS WAY INTO THE REGION BY THIS WEEKEND
INTO EARLY NEXT WEEK, HELPING TO POTENTIALLY KNOCK TEMPERATURES
BACK DOWN A FEW TICKS BELOW NORMAL AS A RESULT.
KEY MESSAGE 2: SLIGHT RISK FOR SEVERE WEATHER ACROSS WESTERN NORTH
CAROLINA THIS EVENING. MORE SEASONALLY-TYPICAL DIURNAL CONVECTION
CONTINUES FOR MOST OF THE WEEK.
CONVECTIVE INITIATION WILL BE A LITTLE LATER THAN THE TYPICAL
START TIME DURING PEAK HEATING AS A VERY WEAK FRONTAL BOUNDARY
ADVANCES ACROSS TENNESSEE THIS AFTERNOON AND MOVES INTO THE REGION
OVERNIGHT TONIGHT. THE ENVIRONMENT THROUGH THE EVENING TIMEFRAME
WILL BE PRIMED FOR SEVERE WEATHER POTENTIAL AHEAD OF THE FRONT WITH
20-25 KTS OF DEEP LAYER SHEAR, 2500-3500 J/KG OF SBCAPE, 1000+
J/KG DCAPE, AND DECENT DRY LAYER IN THE MID-LEVELS TO GO ALONG
WITH STEEP LEVEL LAPSE RATES. CAMS VARY AS FAR AS HOW TO HANDLE
THE COVERAGE FOR CONVECTION AS MOST INITIATE SCATTERED STORMS
OVER EAST TENNESSEE AND PUSH ACROSS THE BORDER OVER THE NORTH
CAROLINA MOUNTAINS SOME TIME AFTER 21Z. WITH JUST ENOUGH SHEAR,
SOME OF THE CONVECTION CAN BECOME LOOSELY ORGANIZED AND WOULD BE
THE MOSTLY LIKELY CULPRIT FOR DAMAGING WIND GUSTS. THE QUESTION
WILL BE HOW FAR EAST CAN THIS ACTIVITY BE MAINTAINED ONCE IT SLIPS
OFF THE TERRAIN INTO THE PIEDMONT ZONES LATER IN THE EVENING,
LIKELY AFTER 8 PM. IN THIS CASE, THE ENVIRONMENT WILL LOSE SOME
OF ITS STEAM, BUT SOME OF THE CAMS ARE KILLING THE ACTIVITY A
LITTLE SOONER THAN WE SHOULD ANTICIPATE AS THE DEWPOINTS ARE
MIXING OUT MORE THAN WHAT'S ACTUALLY HAPPENING IN REAL TIME. THE
MAIN AREA OF CONCERNS WILL BE ACROSS THE NORTH CAROLINA MOUNTAINS,
FOOTHILLS, AND PIEDMONT (MAINLY WEST OF I-77) FROM 4PM-8PM. STILL
CAN'T RULE OUT SEVERE WEATHER ACROSS NORTHEAST GEORGIA AND UPSTATE
SOUTH CAROLINA AFTER 6PM, BUT THE CONDITIONAL THREAT IS LOWER AS
COVERAGE WILL BE MORE ISOLATED IN THESE REGIONS.
AFTER TODAY, THE ATMOSPHERE BECOMES MORE SUPPRESSED AS THE
COLD FRONT SHIFTS SOUTH OF THE AREA AND ANY FEATURE THAT CAN
PROVIDE FORCING FOR ASCENT WILL BE ABSENT TUESDAY AND WEDNESDAY,
LEADING TO MOSTLY JUST SOME RIDGETOP CONVECTION ACROSS THE
MOUNTAINS. CONDITIONS BECOME MORE FAVORABLE FOR AN UPTICK IN
CONVECTION BY THURSDAY INTO THE WEEKEND WITH SHORTWAVE TROUGHS
TRAVERSING ACROSS THE SOUTHEASTERN CONUS, BUT SPECIFIC DETAILS
ARE IN QUESTION THIS FAR OUT.
AVIATION /18Z MONDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: VFR CONDITIONS WILL PREVAIL OUTSIDE OF
SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON AND EVENING, MAINLY
FOR KCLT/KHKY/KAVL. KEPT THE PROB30 FOR TSRA AND ASSOCIATED
RESTRICTIONS FOR THESE TERMINALS, AHEAD OF A COLD FRONT AS
CONFIDENCE WASN'T HIGH ENOUGH FOR A TEMPO AT THIS TIME. WNW TO WSW
WINDS ARE EXPECTED THROUGH THE REMAINDER OF THIS AFTERNOON AND
EVENING BEFORE TURNING OUT OF THE NORTHWEST ON TUESDAY ONCE THE
COLD FRONT PUSHES ACROSS THE AREA BY AROUND 12Z OR SO. CAN'T RULE
OUT SOME LEVEL OF RESTRICTIONS ALONG THE TENNESSEE/NORTH CAROLINA
BORDER WITH MVFR/IFR CLOUD COVER. DEPENDING ON THE EXTENT OF THE
CLOUD COVER, MOUNTAIN VALLEYS THAT ESCAPE THE CLOUD COVER OVERNIGHT
COULD INDUCE SOME FORM OF MOUNTAIN VALLEY FOG/LOW STRATUS, WHICH
MAY IMPACT KAVL AROUND DAYBREAK TUESDAY. NOT EXPECTING SHOWERS OR
THUNDERSTORMS ON TUESDAY, WITH ONLY SOME DAYTIME CU AND HIGH CLOUDS.
OUTLOOK: MORE ISOLATED COVERAGE OF SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE TUESDAY AND WEDNESDAY, MAINLY OVER THE MOUNTAINS. BETTER
CHANCES FOR SHOWERS AND THUNDERSTORMS THURSDAY INTO THE UPCOMING
WEEKEND. LOW STRATUS AND FOG WILL BE POSSIBLE EACH MORNING,
ESPECIALLY IN THE MOUNTAIN VALLEYS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR GAZ018-026-028-
029.
NC...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR NCZ070>072-082.
SC...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR SCZ008>014-019-
104>109.
CAC
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