676
FXUS62 KCAE 211801
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
201 PM EDT FRI AUG 21 2026
WHAT HAS CHANGED
A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FOR THE ENTIRE CWA
UNTIL 9 PM EDT. THUNDERSTORMS WILL DEVELOP THIS AFTERNOON AND
COULD PRODUCE DAMAGING WINDS AND LOCALIZED FLASH FLOODING. 18Z
AVIATION.
KEY MESSAGES
- 1. SEVERE WEATHER AND FLASH FLOODING POSSIBLE TODAY.
DISCUSSION
KEY MESSAGE 1: SEVERE WEATHER AND FLASH FLOODING POSSIBLE
TODAY.
THE FRONTAL BOUNDARY DRAPED FROM THE SOUTHERN PLAINS INTO THE
SOUTHEAST WILL CONTINUE TO INTERACT WITH THE UNSTABLE, WARM AIRMASS
ACROSS THE FA. GOES-E WATER VAPOR IMAGERY SHOWS A CONVECTIVELY
ENHANCED SHORTWAVE AT THE BASE OF THE LARGER TROUGH, WITH A
POSITIVELY TILTED TROUGH EXTENDING BACK INTO CENTRAL GA.
FOLLOWING SOME MORNING CONVECTION ACROSS THE SOUTHEAST PORTION
OF THE FA, STORMS ARE STARTING TO REDEVELOP AND CONTINUE INTO
THIS EVENING ALONG THE WEAK STATIONARY FRONT AND INTERACTION
WITH THE SEA BREEZE/STORM OUTFLOWS.
MOISTURE ADVECTION AND DAYTIME HEATING HAVE ALLOWED MLCAPE
VALUES TO INCREASE TO AROUND 1500-2000 J/KG AND DCAPE VALUES
AROUND 1000-1200 J/KG, WITH POCKETS OF GREATER INSTABILITY
POSSIBLE. PWAT VALUES NEAR 2 INCHES, STEEP LOW-LEVEL LAPSE
RATES, AND WEAK DIVERGENCE ALOFT WILL SUPPORT AN INCREASED RISK
FOR THUNDERSTORMS CAPABLE OF PRODUCING WET MICROBURSTS. DEEP-
LAYER SHEAR REMAINS WEAK, WHICH SHOULD SHOULD HELP LIMIT
WIDESPREAD STORM ORGANIZATION, HOWEVER, SOME STORMS COULD
BECOME SEVERE WITH HEAVY RAINFALL AND DOWNBURST WINDS
DOMINATING. THERE IS ALSO POTENTIAL FOR TRAINING CELLS TO
DEVELOP ALONG THE WEST-EAST-ORIENTED BOUNDARY TO OUR NORTH. THIS
AREA WILL BE OF GREATEST CONCERN FOR FLASH FLOODING, ALTHOUGH
URBAN AREAS AND LOCATIONS THAT ARE TYPICALLY PRONE TO FLOODING
WILL ALSO NEED TO BE MONITORED CLOSELY. CAM GUIDANCE HAS
CONTINUED TO STRUGGLE WITH THE TIMING AND INITIATION OF
CONVECTION, BUT OVERALL ACTIVITY SHOULD GRADUALLY DECREASE AFTER
SUNSET.
AN UPPER TROUGH WILL DIG IN ON SATURDAY, WITH THE AXIS SHIFTING
FARTHER EAST. THIS WILL ALLOW DIRER AIR TO BEGIN MOVING INTO
THE WESTERN PORTION OF OUR FA THIS WEEKEND. HOWEVER, DEEPER
MOISTURE AND MODERATE CONDITIONAL INSTABILITY ALONG THE COAST
COULD SUPPORT ANOTHER THREAT ALONG THE COAST FOR MICROBURSTS
AND DAMAGING WINDS IN THE AFTERNOON, PARTICULARLY NEAR THE I-95
CORRIDOR. BEYOND THAT, A MORE SEASONAL PATTERN IS EXPECTED TO
DEVELOP, WITH TEMPERATURES CLOSER TO NORMAL, INCREASING
HUMIDITY, AND DAILY CHANCES FOR ISOLATED TO SCATTERED SHOWERS
AND THUNDERSTORMS.
AVIATION /18Z FRIDAY THROUGH WEDNESDAY/
TWO PERIODS OF RESTRICTIONS EXPECTED THIS PERIOD. FIRST POTENTIAL
WILL BE IN CONVECTION THIS AFTERNOON AND EVENING. SECOND PERIOD
OF SEEING RESTRICTIONS WILL BE AFTER 06Z THROUGH 15Z.
REGIONAL RADARS SHOWING CONVECTION ALREADY DEVELOPING AND/OR
ONGOING ACROSS THE REGION. VFR CONDITIONS SHOULD PREVAIL OUTSIDE
OF ANY CONVECTION THIS AFTERNOON AND EVENING, WITH PERIODS OF
MVFR/IFR VISIBILITIES IN HEAVY RAIN WITH THE STORMS. ADDITIONAL
RESTRICTIONS ARE NOW BEING SHOWN LATE TONIGHT AND INTO SATURDAY
MORNING, WITH INCREASING POTENTIAL OF IFR/LIFR BETWEEN 06-15Z.
GUIDANCE IS SHOWING THE DEVELOPMENT OF LOW IFR STRATUS AFTER
06Z, WITH SOME PERIOD WITH MVFR VISIBILITIES AT ALL LOCATIONS.
ONLY HAVE MODERATE CONFIDENCE IN THAT RIGHT NOW, BUT HAVE GONE
AHEAD AND INCLUDED RESTRICTIONS OVERNIGHT AT ALL SITES. SOME
IMPROVEMENT TO MVFR SHOULD OCCUR BY 15Z, WITH POSSIBLE VFR NEAR
THE TAIL END OF THE CURRENT TAF PERIOD.
EXTENDED AVIATION OUTLOOK...THUNDERSTORM CHANCES REMAIN INTO
THE WEEKEND, WITH SCATTERED TO WIDESPREAD CONVECTION EXPECTED.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...ND
AVIATION...73
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