922
FXUS62 KCAE 280522
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
122 AM EDT FRI AUG 28 2026
WHAT HAS CHANGED
CONFIDENCE IN ABOVE NORMAL TEMPERATURES INCREASING FOR NEXT
WEEK. AVIATION DISCUSSION UPDATED FOR 06Z TAF ISSUANCE.
KEY MESSAGES
- 1. DIURNAL THUNDERSTORMS EXPECTED THROUGH THE WEEKEND WITH THE
MAIN THREAT OF LOCALLY HEAVY RAINFALL. DRIER CONDITIONS AND
ABOVE NORMAL TEMPERATURES ARE EXPECTED NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: DIURNAL THUNDERSTORMS EXPECTED THROUGH THE
WEEKEND WITH THE MAIN THREAT OF LOCALLY HEAVY RAINFALL. DRIER
CONDITIONS AND ABOVE NORMAL TEMPERATURES ARE EXPECTED NEXT
WEEK.
PERSISTENT TROUGHING IS EXPECTED TO LINGER ACROSS THE REGION
TODAY AND INTO SATURDAY. THIS SHOULD YIELD DEEP SOUTHERLY TO
SOUTHWESTERLY MOISTURE ADVECTION, BRINGING PWAT'S BETWEEN
1.90-2.20" ACROSS THE FA. A WEAK FRONTAL BOUNDARY SINKING OUT OF
THE TENNESSEE VALLEY SHOULD STALL IN THE AREA TODAY, POSSIBLY
ALLOWING A MORE FOCUSED AREA FOR CONVECTION BY THE LATE
AFTERNOON, BUT SCATTERED TO NUMEROUS SHOWERS/STORMS SEEM LIKELY
AGAIN TODAY. THE OVERALL SEVERE RISK IS LIMITED WITH POOR LAPSE
RATES, BUT AROUND 35-45 KTS OF CLOUD LAYER SHEAR IS NOTED IN
MODELED SOUNDINGS, POSSIBLY ALLOWING MAINTENANCE OF ANY MORE
ROBUST UPDRAFT AND THE MARGINAL RISK FOR A COUPLE STRONG TO
DAMAGING WIND GUSTS FROM PRECIP LOADED DOWNBURSTS. THE MAIN RISK
WILL BE LOCALIZED INSTANCES OF HEAVY RAINFALL AND FLASH
FLOODING. PROFILES ARE NEARLY SATURATED THROUGHOUT THE
ATMOSPHERIC COLUMN WITH LONG/SKINNY CAPE PROFILES AND DEEP WARM
CLOUD LAYERS AROUND 13,000 FT. THIS ENVIRONMENT SHOULD MAKE FOR
EFFICIENT RAIN RATES IN EXCESS OF 2-4"/HR (AS WAS SEEN
YESTERDAY) AND SLOW STORM MOTIONS OR TRAINING NEAR THE FRONT
COULD LEAD TO THESE SPOTS OF FLASH FLOODING. DUE TO THIS, THE
CWA REMAINS IN WPC'S SLIGHT RISK FOR EXCESSIVE RAINFALL.
CONTINUED TROUGHING SHOULD YIELD ONE MORE DAY WITH SCATTERED TO
NUMEROUS DIURNAL STORMS SATURDAY BEFORE THE ADVERTISED UPPER
RIDGE SLOWLY WORKS IN TO END THE WEEKEND, BRINGING MORE ISOLATED
TO SCATTERED CHANCES ON SUNDAY. ENSEMBLE GUIDANCE AND LREF
CLUSTER ANALYSIS REMAINS IN FAIRLY GOOD AGREEMENT THAT THE UPPER
RIDGE WILL SHIFT OVERHEAD AND STRENGTHEN THROUGH THE EARLY TO
MID WEEK WITH 500MB HEIGHTS APPROACHING THE NAEFS 99TH
PERCENTILE BY TUESDAY TO WEDNESDAY NEXT WEEK. THIS SHOULD BRING
TEMPERATURES BACK ABOVE NORMAL (AROUND 5-10 DEGREES), ESPECIALLY
WITH DIURNAL CONVECTION LIKELY BEING SUPPRESSED WITH STRONG
SUBSIDENCE UNDER THIS RIDGE. SEASONABLE MOISTURE IS EXPECTED TO
REMAIN IN PLACE, LIKELY AIDING IN BRINGING BACK HEAT INDICES
ABOVE 100F THROUGH THE WEEK WITH LREF PROBABILITIES PEAKING
TUESDAY THROUGH THURSDAY NEAR 60-80%. THIS ANOMALOUS HEAT IS
ALSO SUPPORTED IN THE EC EFI WITH VALUES BETWEEN 0.70 AND 0.80
SEEN BY THE MID WEEK.
AVIATION /06Z FRIDAY THROUGH TUESDAY/
ANOTHER ROUND OF STRATUS AND PATCHY FOG IS EXPECTED TO DEVELOP
OVERNIGHT AND INTO THE MORNING, WITH CIG/VSBY RESTRICTIONS.
ADDITIONAL SHOWERS/STORMS ARE POSSIBLE BY THIS AFTERNOON AND
EVENING.
HIGH LOW LEVEL MOISTURE IS EXPECTED TO YIELD ANOTHER ROUND OF
LOW STRATUS AND SOME PATCHY FOG, ESPECIALLY WHERE RAIN FELL.
SHOULD START TO SEE LOW MVFR STRATUS DEVELOPING AROUND 06Z,
BECOMING MORE WIDESPREAD BY 08Z. THIS MAY BE SLOWED SLIGHTLY BY
SOME BROKEN CIRRUS TRACKING ACROSS THE REGION, BUT STILL
SOMEWHAT CONFIDENT THAT THE LOW STRATUS WILL EVENTUALLY
MATERIALIZE BY 08Z AT ALL SITES. OVERALL, IFR TO PERIODS OF
LIFR CIG AND/OR VSBY RESTRICTIONS WILL BE POSSIBLE, CONTINUING
THROUGH 12-14Z BEFORE GRADUALLY LIFTING THROUGH THE MORNING AND
INTO THE EARLY AFTERNOON. WINDS LIGHT OVERNIGHT, THEN PICK UP
SOME LATE MORNING TO AROUND 5-8 KTS OUT OF THE SOUTH. WHILE AN
ISOLATED SHOWER IS NOT OUT OF THE QUESTION THROUGH THE MORNING,
GREATER RAIN CHANCES OCCUR BY EARLY AFTERNOON AS ANOTHER ROUND
OF SCATTERED CONVECTION IS EXPECTED AFTER 17-19Z, WHICH HAVE
CONTINUED WITH A PROB30 GROUP AT ALL SITES FOR NOW.
EXTENDED AVIATION OUTLOOK... RESTRICTIONS POSSIBLE FROM SHOWERS
AND THUNDERSTORMS INTO THIS WEEKEND. DRIER CONDITIONS EXPECTED
EARLY NEXT WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...DH
AVIATION...73
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