069
FXUS62 KGSP 240546
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
146 AM EDT THU JUL 24 2025
SYNOPSIS
A WARMING TREND BEGIN TODAY, AS A LARGE AREA OF HIGH PRESSURE
BUILDS OVER THE REGION. THE HEAT AND HUMIDITY INCREASES THROUGH
THIS WEEKEND AND INTO EARLY NEXT WEEK WITH DANGEROUS HEAT INDICES
POSSIBLE. THE GREATEST CHANCE FOR AFTERNOON STORMS WILL REMAIN
OVER THE MOUNTAINS WITH JUST ISOLATED TO WIDELY SCATTERED COVERAGE
ELSEWHERE.
NEAR TERM /THROUGH TONIGHT/
AS OF 1234 AM EDT THURSDAY: LOOKS RELATIVELY QUIET THROUGH DAYBREAK,
WITH A LIGHT EASTERLY FLOW AT LOW LEVELS PERHAPS RESULTING IN
SOME EXPANDING STRATOCU AS MOISTURE FROM THE ATLANTIC REACHES
THE MTNS. MTN VALLEY FOG IS NOT A GIVEN WITH THE AIR MASS BEING
RELATIVELY DRY. LOW TEMPS APPEAR TO BE MOSTLY ON TRACK.
NOT MUCH HAPPENING TODAY AND TONIGHT, EITHER, AS THE MID/UPPER
ANTICYCLONE BECOMES BETTER-DEFINED ALONG THE NC COAST TODAY AND THEN
DRIFTS A BIT SOUTHWARD. THE LAST VESTIGES OF THE SFC HIGH PRESSURE
RIDGE FROM THE OLD HIGH WELL OFFSHORE SHOULD VANISH THIS MORNING,
ONLY TO BE REPLACED BY A WEAK HIGH OVER THE MTNS. UNFORTUNATELY,
TODAY IS THE DAY THAT TEMPS START THEIR UPWARD CREEP BACK ABOVE
NORMAL, SO, WARM NOT HOT, WITH THE APPARENT TEMP STAYING IN THE
90S. LITTLE RELIEF IS IN SIGHT FROM PRECIP. THERE'S AN OUTSIDE
CHANCE THAT A SEABREEZE FRONT COULD SEND A SHOWER OR TWO TOWARD THE
EASTERN ZONES LATE IN THE DAY, BUT THE CAMS ARE NOT HOPEFUL. THERE'S
MAYBE A SLIGHTLY BETTER CHANCE OF SOME CONVECTION CREEPING IN FROM
THE SOUTH LATE IN THE DAY AS THE 850MB FLOW VEERS TO SOUTHERLY,
BUT I HAVE A FEELING THE CHANCES ACROSS THE LAKELANDS MIGHT BE TOO
OPTIMISTIC. THE DEVELOPING LIGHT SOUTHERLY FLOW COULD BECOME A BIT
MORE FAVORABLE LATE TONIGHT FOR A FEW SHOWERS TO DEVELOP NORTHWARD
ACROSS NORTHEAST GA INTO THE SOUTHERN MOUNTAINS, WHERE A SMALL
PRECIP PROB WILL BE KEPT. NOT MUCH TO HOPE FOR, IT WOULD APPEAR. LOW
TEMPS WILL BE BACK TO BEING SEASONALLY WARM ONCE AGAIN TONIGHT.
SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/
AS OF 105 AM THURSDAY: THE MAIN STORY HEADING INTO THIS WEEKEND
WILL BE THE BUILDING HEAT AND HUMIDITY ACROSS THE REGION. THIS WILL
BE THANKS TO A LARGE 596-598 DAM 500 MB ANTICYCLONE DOMINATING
THE SOUTHEAST. LOW-LEVEL FLOW WILL BE WEAK, BUT MAINLY OUT OF
THE WEST TO NORTHWEST, PROVIDING EVEN FURTHER WARMING EAST OF
THE MOUNTAINS WITH SOME DOWNSLOPE. THE NBM CONTINUES TO LOOK TOO
HIGH ON DEWPTS EACH AFTN GIVEN DECENT MIXING SHOWN IN THE FCST
SOUNDINGS, SO A BLEND OF THE NBM 10TH PERCENTILE WAS USED TO LOWER
THEM SLIGHTLY. THIS STILL RESULTS IN DEWPTS REMAINING IN THE UPPER
60S TO LOWER 70S. THE DEWPTS COMBINED WITH HIGHS PUSHING INTO
THE UPPER 90S TO OVER 100 RESULTS IN HEAT INDEX VALUES GETTING
INTO THE 105-109 RANGE ACROSS MUCH OF THE CHARLOTTE AREA AND THE
UPPER SAVANNAH VALLEY AND LAKELANDS FOR SATURDAY. SUBSIDENCE AND
WEAK MID-LEVEL LAPSE RATES WILL KEEP CONVECTION FAIRLY SUPPRESSED,
WITH JUST SCATTERED SHOWERS AND ISOLATED STORMS IN THE MOUNTAINS
AND A STRAY SHOWER OR TWO ELSEWHERE. WILL CONTINUE TO ADVERTISE
THE POTENTIAL NEED FOR A HEAT ADVISORY FOR PORTIONS OF THE PIEDMONT
IN THE HWO.
LONG TERM /SUNDAY THROUGH WEDNESDAY/
AS OF 130 AM THURSDAY: THE LONGEST AND LIKELY THE MOST DANGEROUS
HEAT WAVE OF THE SUMMER WILL BE THE MAIN WEATHER STORY FOR
THE ENTIRE MEDIUM RANGE, WITH AN ELONGATED 596-598 DAM 500 MB
RIDGE EXTENDING FROM THE SOUTHEAST ALL THE WAY TO THE SOUTHERN
ROCKIES. THE CENTER OF THE UPPER HIGH WILL SLOWLY DRIFT WEST TO THE
CENTRAL PLAINS BY TUESDAY. BUT THE EASTERN EDGE OF THE RIDGE WILL
PERSIST THRU AT LEAST WEDNESDAY. OVERALL, NOT MUCH CHANGE IN THE
FORECAST FOR SUNDAY THRU WEDNESDAY. EACH DAY HIGHS WILL CONTINUE TO
BE IN THE UPPER 90S TO AROUND 102 EAST OF THE MOUNTAINS. EVEN WITH
SOME MIXING OF DEWPTS IN THE 60S, HEAT INDEX VALUES WILL BE PUSHING
INTO THE 105-109 DEG ADVISORY CRITERIA RANGE. THERE MAY EVEN BE
SOME 110-112 IN THE FAR SOUTHERN ZONES OF ELBERT TO GREENWOOD AND
AROUND CHARLOTTE, IF THE DEWPTS DON'T MIX OUT ENOUGH. UNFORTUNATELY,
DIURNAL CONVECTION WILL NOT PROVIDE MUCH RELIEF, BEING MAINLY
LIMITED TO THE MOUNTAINS EACH AFTN, AND ISOLATED TO SCATTERED IN
NATURE, GIVEN THE OPPRESSIVE RIDGE ALOFT. HOPEFULLY THE HEAT WAVE
WILL BEGIN TO BREAK JUST BEYOND THE MEDIUM RANGE, AS THE ENSEMBLES
AGREE ON THE UPPER RIDGE RETROGRADING FURTHER WEST AND ALLOWING
A TROUGH TO DIG INTO THE NORTHEAST.
AVIATION /06Z THURSDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: WATCHING PATCHY LOW CLOUDS MOVING UP FROM
THE ATLANTIC AT THIS LATE HOUR. CLOUD BASES WERE WELL INTO THE VFR
CATEGORY, SO THERE IS NO IMMEDIATE CONCERN OTHER THAN AN OCCASIONAL
BKN050 AT KCLT THRU THE EARLY MORNING HOURS, BUT THERE IS SOME
INDICATION THAT AS THE MOISTURE RUNS UP AGAINST THE BLUE RIDGE
ESCARPMENT THERE COULD BE A TEMPORARY MVFR CEILING RESTRICTION AT
KHKY. THAT WILL BE CARRIED FORTH. THERE'S LESS OF AN INDICATION OF
MTN VALLEY FOG THRU DAYBREAK BECAUSE OF THE DRY AIR MASS. WIND WILL
BE LIGHT NE, BUT WILL PROBABLY GO VARIABLE TOWARD DAYBREAK. FOR
THURSDAY, JUST A FEW STRATOCU THROUGH THE AFTERNOON WITH WIND
EVENTUALLY COMING AROUND TO LIGHT SE TO S.
OUTLOOK: COVERAGE OF DIURNAL CONVECTION IS EXPECTED TO PICK BACK
UP ACROSS THE MOUNTAINS FRIDAY THROUGH MONDAY WITH LOWER CHANCES
ELSEWHERE. LOW STRATUS AND/OR FOG WILL BE POSSIBLE EACH MORNING,
ESPECIALLY IN THE MTN VALLEYS.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...ARK
NEAR TERM...PM
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...PM
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