468
FXUS62 KGSP 081038
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
638 AM EDT TUE JUL 8 2025
SYNOPSIS
HOT AND HUMID CONDITIONS WILL CONTINUE THRU MIDWEEK WITH DAILY
AFTERNOON AND EVENING SHOWER AND THUNDERSTORM CHANCES. THE HEAT
ABATES SOMEWHAT GOING INTO THE WEEKEND, BUT DAILY AFTERNOON AND
EVENING SHOWER AND THUNDERSTORM CHANCES CONTINUE.
NEAR TERM /THROUGH TONIGHT/
AS OF 635 AM TUESDAY: MOUNTAIN VALLEY FOG THIS MORNING WILL
DISSIPATE RELATIVELY QUICKLY THIS MORNING. PATCHY FOG ELSEWHERE
BURNS OFF QUICKLY AS WELL.
A WEAK UPPER ANTI-CYCLONE REMAINS OVER THE AREA TODAY BUT BEGINS TO
WEAKEN AND MOVE EAST THROUGH TONIGHT. A LEE TROUGH DEVELOPS OVER THE
AREA WITH A COLD FRONT REMAINING WELL TO OUR NORTH. AN UNSTABLE AIR
MASS REMAINS OVER THE AREA TODAY. MOISTURE POOLS OVER THE MOUNTAINS
AND EAST OF THE LEE TROUGH, BUT THERE IS DRYING BETWEEN THE TWO.
EXPECT DIURNAL CONVECTION ONCE AGAIN WITH BETTER COVERAGE OVER THE
MOUNTAINS AND EAST TAPERING OFF TO ISOLATED COVERAGE SOUTH OF I-85.
THE ONE EXCEPTION COULD BE A DIFFERENTIAL HEATING BOUNDARY SETTING
UP EAST OF I-77 WHICH THE CAMS SHOW WITH BETTER COVERAGE DEVELOPING
ALONG IT. RIGHT NOW, THE BETTER COVERAGE WITH THAT FEATURE SHOULD BE
TO OUR EAST, BUT IF THE FEATURE DEVELOPS FARTHER WEST, THEN COVERAGE
OVER THE CLT METRO COULD BE HIGHER. SBCAPE RISES TO AROUND 2000 J/KG
BUT IT'S MORE OF A TALL/SKINNY CAPE WITH HIGH LFC'S BETWEEN THE
MOUNTAINS AND DIFFERENTIAL HEATING BOUNDARY WHERE DRYING OCCURS.
EVEN WHERE THERE IS MOISTURE POOLING, DECENT DCAPE AND SFC DELTA
THETA-E DEVELOPS, BUT BULK SHEAR IS 20 KTS OR LESS LIMITING ANY
POTENTIAL STORM ORGANIZATION. SPC HAS A MARGINAL RISK FOR SEVERE
STORMS WITH DAMAGING WINDS ALONG AND EAST OF I-77. THIS MAKES SENSE
GIVEN THE AFORE MENTIONED PARAMETERS, BUT AN ISOLATED SEVERE STORM
WILL BE POSSIBLE ACROSS THE MOUNTAINS AS WELL.
HIGHS WILL BE IN THE MID TO UPPER 90S OUTSIDE OF THE MOUNTAINS AND
AROUND 90 IN MANY MOUNTAIN VALLEYS. WITH DEW POINTS MIXING OUT AGAIN
DURING THE AFTERNOON, THE HEAT INDEX TOPS OUT BELOW 105, BUT MANY
LOCATIONS ALONG AND SOUTH OF I-85 WILL SEE VALUES OF 100 OR HIGHER.
CONVECTION DIMINISHES AND WEAKENS DURING THE EVENING AND SHOULD END
BY MIDNIGHT. SKIES CLEAR OUT WITH MOUNTAIN VALLEY FOG EXPECTED. LOWS
WILL BE NEAR NORMAL ACROSS THE MOUNTAINS AND UP TO 5 DEGREES ABOVE
NORMAL ELSEWHERE.
SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/
AS OF 1:45 AM EDT TUESDAY: THE SHORT-TERM FCST PICKS UP AT 12Z
ON WEDNESDAY WITH BROAD UPPER RIDGING TO OUR EAST AND WEST. ON
WEDNESDAY, AN UPPER SHORTWAVE WILL PROPAGATE INTO THE OH AND TN
VALLEYS, RESULTING IN HEIGHT FALLS OVER OUR AREA AND SLIGHTLY
LOWER THICKNESSES. THIS FEATURE WILL PROVIDE SOME AMOUNT OF UPPER
SUPPORT FOR OUR FCST AREA AS DIURNAL HEATING PRODUCES SFC-BASED
CAPE OF 1000 TO 2000 J/KG. CATEGORICAL POPS ARE FCST ACROSS THE
MTNS AND NC PIEDMONT WITH LIKELY POPS OVER MUCH OF UPSTATE SC AND
THE GA PIEDMONT. BULK-SHEAR VALUES INCREASE SLIGHTLY AHEAD OF THE
TROF BUT VALUES ARE NOT GENERALLY SUPPORTIVE OF ORGANIZED CONVEC-
TION. NONETHELESS, MODEL PROFILES SUGGESTS THAT THERE WILL BE ENOUGH
MID AND UPPER-LEVEL DRY AIR TO SUPPORT ISOLATED DAMAGING MICROBURSTS.
PWS OF 1.5 TO 2" AND FAIRLY UNIDIRECTIONAL LOW AND MID-LEVEL FLOW
WILL LIKELY SUPPORT CELL TRAINING CAPABLE OF PRODUCING ISOLATED
AREAS OF EXCESSIVE RAINFALL/FLOODING. THE INCREASED CLOUD COVER
SHOULD HELP KEEP HIGH TEMPERATURES A FEW DEGREES COOLER THAN TUES,
THOUGH STILL A FEW DEGREES ABOVE-NORMAL FOR MID-JULY. WHILE AFTN
MIXING IS EXPECTED TO LOWER DEWPTS A FEW DEGREES, HEAT INDICES WILL
LIKELY APPROACH THE 100 TO 103 DEGREE RANGE OVER PORTIONS OF THE
UPSTATE AND THE CLT METRO AREA. WE CAN EXPECT SIMILAR UNSETTLED
WEATHER AND CONVECTIVE COVERAGE FOR THURSDAY AFTN AND EVENING.
PERSISTENT SWLY LOW-LEVEL FLOW AND FAVORABLE STORM-MOTION VECTORS
SUGGEST A CONTINUED RISK FOR ISOLATED AREAS OF EXCESSIVE RAINFALL
AND LOCALIZED FLOODING. BULK-SHEAR VALUES ARE FCST TO INCREASE
SLIGHTLY, APPROACHING 25 KTS. DESPITE TALL AND SKINNY CAPE PRO-
FILES, A WET MICROBURST THREAT WILL CONTINUE WHERE THE STRONGEST
UPDRAFTS CAN DEVELOP. HIGH TEMPERATURES SHOULD FALL A FEW DEGREES
COMPARED TO WEDNESDAY WITH VALUES NEAR CLIMATOLOGY FOR MID-JULY.
LONG TERM /FRIDAY THROUGH MONDAY/
AS OF 1:35 AM EDT TUESDAY: THE EXTENDED PERIOD PICKS UP AT 12Z ON
FRIDAY AND IS EXPECTED TO REMAIN FAIRLY ACTIVE THRU THE PERIOD.
OUR AREA WILL REMAIN SANDWICHED BETWEEN THE BROAD, SUBTROPICAL
BERMUDA HIGH TO OUR EAST AND BROAD, WEAK HIGH PRESSURE TO OUR
WEST AND NORTH. THIS WILL KEEP MOIST, SLY TO SWLY LOW-LEVEL FLOW
OVER OUR AREA THRU MOST OF THE PERIOD. ALOFT, NUMEROUS WEAK SHORT-
WAVES WILL MOVE ACROSS THE OH AND TN VALLEYS AND OVER THE CENTRAL
AND SOUTHERN APPALACHIANS THRU THE PERIOD. THIS ENERGY ALOFT WILL
HELP SUPPORT LIKELY TO CATEGORICAL POPS OVER THE MTNS AND FOOTHILLS
WITH CHANCE POPS OVER THE PIEDMONT EACH AFTERNOON/EVENING. AT THIS
TIME, THERE DOESN'T APPEAR TO BE A SIGNIFICANT SEVERE WX THREAT ANY
PARTICULAR DAY, WITH ISOLATED DAMAGING WET MICROBURSTS POSSIBLE EACH
DAY. WITH THE PERSISTENT MOIST AIRMASS IN PLACE, THE BIGGER THREAT
WILL LIKELY BE EXCESSIVE RAINFALL FROM THUNDERSTORMS THAT COULD PRO-
DUCE LOCALIZED FLOODING. OTHERWISE, HIGH TEMPERATURES ARE EXPECTED
TO START OUT NEAR-NORMAL ON FRIDAY AND GRADUALLY WARM UP TO A CATE-
GORY ABOVE NORMAL BY SUNDAY. DEWPTS ARE EXPECTED TO REMAIN LOW ENOUGH
TO KEEP HEAT INDICES BELOW HEAT ADVISORY CRITERIA, ALTHOUGH SOME
VALUES BETWEEN 100 AND 105 DEGREES ARE POSSIBLE OVER OUR SOUTHERN
UPSTATE AND PIEDMONT ZONES ON SUNDAY AND MONDAY.
AVIATION /12Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: THIN CIRRUS, AND LIGHT AND VARIABLE WINDS,
AND MOUNTAIN VALLEY FOG TO START THE MORNING. FOG DISSIPATES THEN SW
WIND, NW AT KAVL, PICKS UP THROUGH THE MORNING WITH CU DEVELOPING.
DIURNAL CONVECTION EXPECTED WITH BEST CHANCE AT KAVL BUT ENOUGH OF A
CHANCE FOR PROB30S AT ALL BUT KAND. SKIES CLEAR OUT OVERNIGHT WITH
WINDS BECOMING LIGHT AND VARIABLE. MOUNTAIN VALLEY FOG EXPECTED ONCE
AGAIN.
OUTLOOK: TYPICAL SUMMERTIME WEATHER IS EXPECTED INTO THE WEEKEND,
WITH SCT TO NUMEROUS SHRA/TSRA MAINLY IN THE AFTN/EVENING AND FOG
AND/OR LOW STRATUS POSSIBLE EACH MORNING.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...JPT
NEAR TERM...RWH
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...RWH
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