846
FXUS62 KCAE 210553
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
153 AM EDT FRI AUG 21 2026
WHAT HAS CHANGED
AVIATION DISCUSSION UPDATED FOR 06Z TAFS.
KEY MESSAGES
- 1. SEVERE WEATHER AND FLASH FLOODING POSSIBLE FRIDAY.
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.
AVIATION /06Z FRIDAY THROUGH TUESDAY/
VFR CONDITIONS EXPECTED THROUGH THIS MORNING, WITH RESTRICTIONS
EXPECTED IN CONVECTION THIS AFTERNOON AND EVENING.
QUIET WEATHER IS IN PLACE ACROSS THE AREA CURRENTLY. THERE HAVE
BEEN SOME PERSISTENT SHOWERS AND STORMS ACROSS THE UPSTATE AND
SOUTHERN NC OVER THE LAST SEVERAL HOURS BUT WE HAVE REMAINED
QUIET. MOISTURE IS FORECAST TO RETURN IN A HURRY AHEAD OF AN
APPROACHING SURFACE LOW AND SURFACE 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 BETWEEN 15Z AND 17Z.
FORECAST SOUNDINGS ARE QUITE IMPRESSIVE FOR THIS SETUP, WITH
PLENTY OF MOISTURE AND INSTABILITY TO YIELD WIDESPREAD, STRONG
THUNDERSTORMS THROUGHOUT THIS AFTERNOON. GIVEN ROBUST FORCING
(ESP FOR AUGUST), PLENTIFUL MOISTURE, AND STRONG INSTABILITY
IN PLACE, FEEL COMFORTABLE TARGETING THE 17Z-21Z TIMEFRAME FOR A
TEMPO FOR TSRA, LOWERED VISIBILITIES, AND STRONG WIND GUSTS.
THIS MAY NEED TO BE ADJUSTED IF CONVECTION BEGINS EARLIER BUT
THIS SEEMS LIKE A GOOD STARTING POINT FOR THE TEMPO GROUP.
EXPECTING THE CONVECTION TO LIKELY WIND DOWN IN THE 21Z TO 00Z
TIMEFRAME, WITH RAIN SHOWERS EXPECTED TO PERSIST INTO THE
EVENING HOURS. CLOUDS WILL BE COPIOUS DURING THIS TIME, AND AS
THE AFORMENTIONED SURFACE LOW AND SURFACE BOUNDARY MOVE TO OUR
SOUTH/EAST BY TONIGHT, GUIDANCE IS HINTING AT SOME MVFR OR IFR
CIGS DEVELOPING. THIS IS PRETTY UNCERTAIN RIGHT NOW BUT IF
RAINFALL IS WIDESPREAD AND PERSISTENT ENOUGH, IT WON'T BE TOUGH
TO GET SOME CEILING RESTRICTIONS. HAVE TRENDED TOWARDS THIS
BEGINNING IN THE 03Z GROUP.
EXTENDED AVIATION OUTLOOK...THUNDERSTORM CHANCES REMAIN INTO
THE WEEKEND, WITH SCATTERED TO WIDESPREAD CONVECTION EXPECTED.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...CJR
AVIATION...PL
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