009
FXUS62 KGSP 131831
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
231 PM EDT MON JUL 13 2026
WHAT HAS CHANGED
SEVERE THUNDERSTORM THREAT HAS DECREASED FOR THE REST OF
TODAY. OTHERWISE, NO SIGNIFICANT CHANGES TO THE FORECAST WITH THE
AFTERNOON PACKAGE.
THE AVIATION DISCUSSION HAS BEEN UPDATED FOR THE 18Z TAFS.
KEY MESSAGES
1. WIDESPREAD SHOWERS AND ISOLATED TO SCATTERED THUNDERSTORMS
EXPECTED ACROSS THE AREA THROUGH THIS EVENING. A FLASH FLOOD WATCH
REMAINS IN EFFECT FOR PORTIONS OF THE NORTHERN NC MOUNTAINS AND
NORTHERN FOOTHILLS UNTIL 8 PM TODAY. LOCALIZED FLASH FLOODING WILL
BE POSSIBLE ACROSS THE REMAINDER OF THE AREA AS WELL. OTHERWISE,
WELL-BELOW NORMAL HIGH TEMPERATURES ARE FORECAST THROUGH TUESDAY.
2. A RETURN TO SEASONABLY HOT AND DRIER CONDITIONS IS EXPECTED
FROM WEDNESDAY THROUGH THE REST OF WEEK. A COLD FRONT WILL APPROACH
FROM THE NORTH AND BRING HIGHER RAIN CHANCES OVER THE WEEKEND.
DISCUSSION
KEY MESSAGE 1: WIDESPREAD SHOWERS AND ISOLATED TO SCATTERED
THUNDERSTORMS EXPECTED ACROSS THE AREA THROUGH THIS EVENING. A
FLASH FLOOD WATCH REMAINS IN EFFECT FOR PORTIONS OF THE NORTHERN
NC MOUNTAINS AND NORTHERN FOOTHILLS UNTIL 8 PM TODAY. LOCALIZED
FLASH FLOODING WILL BE POSSIBLE ACROSS THE REMAINDER OF THE AREA AS
WELL. OTHERWISE, WELL-BELOW NORMAL HIGH TEMPERATURES ARE FORECAST
THROUGH TUESDAY.
A WEAK STACKED LOW CONTINUES TO SPIN ACROSS EASTERN TN, WITH AN
AXIS OF 1.5-2.0" PWATS ACROSS REGION. THE DEEP-LAYER MOISTURE
AND WEAK LAPSE RATES ARE RESULTING IN MODESTLY UNSTABLE AIR,
WITH SBCAPE 500-1500 J/KG ACROSS MOST OF THE CWFA, AND AROUND
2000 J/KG IN FAR SOUTHERN PARTS OF THE AREA. WIDESPREAD CONVECTION
HAS DEVELOPED WITH THE SUBTLE CYCLONIC SPIN APPARENT ON THE RADAR
MOSAIC. THE VAST MAJORITY OF THE ACTIVITY IS TOO SHALLOW TO PRODUCE
LIGHTNING, WITH JUST A FEW GENERAL THUNDERSTORMS ACROSS THE CWFA
ATTM. NOT SURPRISING THAT THE SEVERE THREAT LOOKS TO BE TRENDING
DOWN. THE MAIN CONCERN WILL BE HEAVY RAIN AND LOCALIZED FLASH
FLOODING. SHOWERS ARE PRODUCING EFFICIENT RAIN RATES, WITH SOME
ADVISORY-LEVEL FLOODING POSSIBLE. WHERE CELLS CAN TRAIN OVER THE
SAME AREAS, FLASH FLOODING MAY OCCUR. THE 12Z CAMS HAVE TRENDED
TOWARD THE HEAVIEST RAINFALL ACROSS THE SOUTHERN NC FOOTHILLS TO
THE NW PIEDMONT, MOSTLY ON THE SOUTH SIDE OF THE CURRENT FLASH FLOOD
WATCH. WITH THAT SAID, FLOODING IS EXPECTED TO BE TOO LOCALIZED TO
WARRANT EXPANDING THE WATCH. FURTHER SOUTH ACROSS THE UPSTATE AND
NE GA, INSTABILITY IS HIGHER AND A WEAK FRONT HAS STALLED OUT. SO
ISOLATED FLOODING CANNOT BE RULED OUT IN THESE AREAS EITHER. TEMPS
WILL REMAIN ABOUT 10-15 DEG BELOW NORMAL THE REST OF THE AFTN.
CONVECTION IS EXPECTED TO DECREASE THIS EVENING AFTER SUNSET,
BUT SCATTERED SHOWERS WILL CONTINUE DEVELOP NEAR THE ESCARPMENT
AND ADJACENT FOOTHILLS OVERNIGHT, AS EASTERLY UPSLOPE FLOW WILL
LINGER WITH A LITTLE MUCAPE. THERE IS NOT MUCH OF A SIGNAL FOR
HEAVY RAIN, AND THUS, EXPECT THE FFA WILL BE ALLOWED TO EXPIRE
AT 8 PM THIS EVENING. LOWS WILL BE NEAR TO SLIGHTLY BELOW NORMAL
UNDER MOSTLY CLOUDY SKIES.
THE STACKED LOW WILL BEGIN TO RETROGRADE WEST, AS HIGH PRESSURE
BUILDS TOWARD THE SE FROM THE UPPER MIDWEST. LOW-LEVEL FLOW WILL
BEGIN TO TURN OUT OF THE ENE AND ADVECT IN SOME DRIER AIR TO THE
CWFA. THE GLOBAL MODELS SUGGEST THE AIR MASS WILL STILL BECOME
MODESTLY UNSTABLE, DESPITE LINGERING CLOUD COVER SLOW TO SCATTER
OUT. THE 12Z CAMS ARE NOT VERY EXCITED ABOUT DIURNAL CONVECTION,
SHOWING ALMOST NO ACTIVITY IN THE FORECAST AREA. THE LATEST NBM
IS IN BETWEEN, WITH POPS RANGING FROM SUB-15 NORTH OF I-40 TO
AROUND 60% IN NE GA. A NON-ZERO HEAVY RAIN THREAT MAY LINGER IN
OUR SOUTHWEST ZONES, AS PWATS REMAIN NEAR 2 INCHES. TEMPS WILL BE
ABOUT 5-10 DEG BELOW NORMAL.
KEY MESSAGE 2: A RETURN TO SEASONABLY HOT AND DRIER CONDITIONS IS
EXPECTED FROM WEDNESDAY THROUGH THE REST OF WEEK. A COLD FRONT
WILL APPROACH FROM THE NORTH AND BRING HIGHER RAIN CHANCES OVER
THE WEEKEND.
A LARGE UPPER RIDGE WILL BUILD SOUTHEASTWARD FROM THE NORTHERN
PLAINS WEDNESDAY, SETTLING INTO A NW-SE-AXIS FROM THE UPPER MIDWEST
TO THE CAROLINAS THURSDAY AND FRIDAY. THIS PATTERN SHOULD ALLOW
A DRIER AIR TO ROTATE IN FROM THE NE AND RESULT IN BELOW-CLIMO
POPS FOR THE LATTER HALF OF THE WORKWEEK (MAINLY CONFINED TO THE
HIGH TERRAIN AND PIEDMONT WEST OF I-26). TEMPS WILL WARM TO NEAR
NORMAL WEDNESDAY, THEN A FEW DEGREES ABOVE NORMAL THURSDAY AND
BEYOND. MUGGY DEWPTS WILL SUPPORT HEAT INDICES CREEPING BACK UP
NEAR 100 TO 105 ACROSS THE SOUTHERN AND EASTERN PORTIONS OF THE
CWFA. THERE IS STILL NO CLEAR INDICATION THAT HEAT ADVISORIES WILL
BE NEEDED, BUT IT WILL FEEL HOT NEVERTHELESS.
THE 12Z GUIDANCE IS COMING INTO BETTER AGREEMENT ON A COLD FRONT
DROPPING SOUTH TOWARD THE FORECAST AREA SATURDAY AND POSSIBLY
REACHING HTE AREA SUNDAY. THIS BRINGS BACK NEAR TO ABOVE-CLIMO
DIURNAL CONVECTIVE POPS.
AVIATION /18Z MONDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: NUMEROUS TO WIDESPREAD SHOWERS ARE
BLOSSOMING ACROSS THE AREA THIS AFTERNOON AND WILL CONTINUE INTO
EARLY EVENING. THERE ARE A FEW EMBEDDED GENERAL THUNDERSTORMS, AND
THE THREAT SEEMS HIGH ENOUGH TO KEEP PROB30 FOR TSRA IN ALL THE TAF
SITES (EXCEPT HKY, WHICH IS UNDER THICKER CLOUD COVER). CLOUDS HAVE
SCATTERED INTO SEVERAL LOW LAYERS, BUT CIGS ARE MOSTLY MVFR WITH
OCCASIONAL VFR. EXPECT SHOWER COVERAGE TO DECREASE THIS EVENING,
BUT LINGERING LIGHT RAIN AND DRIZZLE WILL BE POSSIBLE THRU MOST
OF THE OVERNIGHT, ESPECIALLY NEAR THE BLUE RIDGE ESCARPMENT. CIGS
ARE EXPECTED TO LOWER TO IFR, WITH LIFR POSSIBLE IN SPOTS, MAINLY
NEAR THE ESCARPMENT. CIGS SHOULD START TO LIFT TO MVFR BY MIDDAY
TUESDAY, BUT NOT LIKELY TO REACH VFR BEFORE 18Z. WINDS WILL MOSTLY
BE ENE AT 5-10 KT THRU THE PERIOD, EXCEPT ESE AT KAVL.
OUTLOOK: DRIER CONDITIONS SHOULD DEVELOP TUESDAY INTO WEDNESDAY.
LOW STRATUS AND/OR FOG WILL BE POSSIBLE EACH MORNING IN THE MTN
VALLEYS AND IN LOCATIONS THAT RECEIVE APPRECIABLE RAINFALL FROM
THE PREVIOUS DAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...FLOOD WATCH UNTIL 8 PM EDT THIS EVENING FOR NCZ033-035-049-050-
501>506.
SC...NONE.
ARK
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