643
FXUS62 KCAE 210035
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
835 PM EDT THU AUG 20 2026
WHAT HAS CHANGED
AN ISOLATED SHOWER OR STORM IS POSSIBLE THIS EVENING, BUT EXPECT
MOSTLY DRY CONDITIONS INTO FRIDAY MORNING. THE REMAINDER OF THE
FORECAST REMAINS ON TRACK FOR WIDESPREAD CONVECTION FRIDAY
AFTERNOON WITH FLASH FLOODING AND DAMAGING WINDS POSSIBLE.
AVIATION DISCUSSION UPDATED FOR 00Z TAFS.
KEY MESSAGES
- 1. SEVERE WEATHER AND FLASH FLOODING POSSIBLE FRIDAY.
- 2. AN ISOLATED SHOWER OR STORM POSSIBLE THIS EVENING.
DISCUSSION
KEY MESSAGE 1: SEVERE WEATHER AND FLASH FLOODING POSSIBLE
FRIDAY.
THE FORECAST FOR FRIDAY LARGELY REMAINS ON TRACK AS TROUGHING
OVER THE EASTERN CONUS STRENGTHENS WITH ANOTHER SHORTWAVE
GRADUALLY WORKING TOWARD THE REGION. ALONG WITH THIS UPPER
SUPPORT, A SURFACE FRONT IS ALSO EXPECTED TO SHIFT INTO THE
REGION THROUGH THE DAY. ROBUST HEATING IS EXPECTED THROUGH THE
MORNING INTO THE AFTERNOON WITH SURFACE DEWPOINTS IN THE LOW TO
MID 70S. THIS SHOULD QUICKLY BRING MLCAPE VALUES NEAR 2500-3000
J/KG WITH STEEP LOW LEVEL LAPSE RATES BRINGING DCAPE VALUES NEAR
800-1000 J/KG. ENHANCED KINEMATICS WITH SURGING PWAT'S TO NEAR
2" WILL BRING THE RISK FOR WET MICROBURSTS IN CONVECTION DURING
THE EARLY AFTERNOON. WHILE DAMAGING WIND GUSTS ARE THE PRIMARY
THREAT, CANNOT RULE OUT SOME HAIL AS FAIRLY THICK CAPE PROFILES
ARE SEEN IN THE HAIL GROWTH ZONE. THIS IS FURTHER SUPPORTED IN
ANALOG SOUNDINGS WITH MULTIPLE ANALOGS FOR NEAR SEVERE HAIL WHEN
PULLING FORECAST SOUNDINGS FROM THE RAP/HRRR/RRFS. 12Z GUIDANCE
INDICATES CONVECTION COULD GET GOING AS EARLY AS 16- 19Z,
QUICKLY EXPANDING IN COVERAGE THROUGH THE AFTERNOON AND INTO THE
EARLY EVENING.
THE OVERALL STORM MOTION IS EXPECTED TO BE FAIRLY SLOW (UNDER
20 KTS) AND THE ENVIRONMENT APPEARS PRIMED FOR HEAVY RAINFALL
WITH DEEP WARM CLOUD DEPTHS, NEARLY BOUNDARY PARALLEL DEEP LAYER
SHEAR VECTORS, AND PWAT'S NEAR 2". THE RECENT REFS AND HREF PMM
QPF AMOUNTS SHOW SPOTS OF 2-4" NEAR PORTIONS OF THE PEE DEE AND
NORTHERN MIDLANDS, WHICH IS REASONABLE, BUT BOTH OF THESE
ENSEMBLES ARE KEYING IN ON AMOUNTS NEAR 3-6" JUST ACROSS THE
CWA BORDER IN SOUTHERN NC. ANY SOUTHERN SHIFT IN FORCING/ THIS
AXIS OF HIGHER QPF COULD BRING THE HIGHER AMOUNTS IN THE PEE DEE
AND NORTHERN FA. OVERALL, SOME UNCERTAINTY REMAINS IN THE EXACT
PLACEMENT OF THE HEAVIEST RAINFALL, BUT ISOLATED TO SCATTERED
INSTANCES OF FLASH FLOODING WILL BE POSSIBLE MAINLY ALONG AND
EAST OF THE I-26 CORRIDOR.
KEY MESSAGE 2: AN ISOLATED SHOWER OR STORM POSSIBLE THIS
EVENING.
CONVECTION KICKED OFF A BIT EARLIER THAN EXPECTED WITH A COUPLE
STRONG TO SEVERE STORMS THIS AFTERNOON THAT GENERALLY HELPED TO
STABILIZE CONDITIONS. A FEW STORMS HAVE QUICKLY FIRED BOTH
NORTH AND SOUTH OF THE FORECAST AREA IN THE LAST HOUR OR SO AS A
RESULT OF SOME REMNANT OUTFLOW BOUNDARIES. WHILE PRECIP SHOULD
BE MAINLY DONE FOR THE NIGHT, GIVEN THE LATEST TRENDS AN
ISOLATED STRONG STORM COULD REMAIN POSSIBLE INTO LATE THIS
EVENING.
AVIATION /00Z FRIDAY THROUGH TUESDAY/
VFR CONDITIONS EXPECTED THROUGH FRIDAY MORNING, WITH
RESTRICTIONS EXPECTED IN CONVECTION FRIDAY AFTERNOON AND
EVENING.
THE CONVECTION FROM EARLIER THIS AFTERNOON HAS BEEN REPLACED BY
MOSTLY CLEAR SKIES. GOES PW IMAGERY SUGGESTS THAT SLIGHTLY DRIER
AIR HAS OVERSPREAD THE AREA, MAKING ANOTHER ROUND OF CONVECTION
SEEM SOMEWHAT UNLIKELY THIS EVENING. THIS IS SUPPORTED BY A
LULL IN UPPER SUPPORT THAT IS EXPECTED TO INCREASE RAPIDLY ON
FRIDAY. MOISTURE IS FORECAST TO RETURN IN A HURRY AHEAD OF AN
APPROACHING SURFACE LOW AND TROUGH ON FRIDAY MORNING. SOUTHERLY
AND SOUTHEASTERLY FLOW WILL CONTINUE TO PUSH HIGHER PW AIR IN
PLACE AS A SURFACE LOW DEVELOPS OVERHEAD. CONVECTION IS EXPECTED
TO BEGIN EARLY AGAIN - LIKELY AROUND 15Z OR 16Z. ADDED A
PREDOMINANT VCTS TO THE TAFS WITH A LONG PROB30 FOR TSRA FROM
16Z TO 22Z. WHILE THIS IS AN ESCALATION FROM THE PREVIOUS
FORECAST, IT IS LIKELY THAT A PREDOMINANT TSRA GROUP WILL BE
NEEDED WITH THE 06Z OR 12Z ISSUANCE AS CONVECTION LOOKS
WIDESPREAD FOR MUCH OF THE AFTERNOON TOMORROW. EXPECT VISIBILITY
RESTRICTIONS & STRONG WIND GUSTS AS THE PRIMARY AVIATION
PROBLEMS, WITH CEILINGS LIKELY DEPENDENT ON PERSISTENCE OF
WIDESPREAD, HEAVY RAINFALL INTO THE EVENING HOURS.
EXTENDED AVIATION OUTLOOK...THUNDERSTORM CHANCES REMAIN INTO
THE WEEKEND, WITH SCATTERED TO WIDESPREAD CONVECTION EXPECTED.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...DH/EC
AVIATION...PL
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