790
FXUS62 KCAE 300051
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
851 PM EDT SAT AUG 29 2026
WHAT HAS CHANGED
AVIATION DISCUSSION UPDATED FOR 00Z TAF ISSUANCE.
KEY MESSAGES
- 1. DIURNAL THUNDERSTORMS EXPECTED THROUGH THIS WEEKEND WITH
THE MAIN THREAT OF LOCALLY HEAVY RAINFALL.
- 2. WELL ABOVE NORMAL TEMPERATURES WITH DANGEROUS HEAT INDEX
VALUES POSSIBLE NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: DIURNAL THUNDERSTORMS EXPECTED THROUGH THIS
WEEKEND WITH THE MAIN THREAT OF LOCALLY HEAVY RAINFALL.
A FEW LINGERING SHOWERS AND THUNDERSTORMS ARE HANGING AROUND
THIS EVENING NEAR THE EASTERN MIDLANDS AND COASTAL PLAIN WHERE
DEEPER MOISTURE EXISTS AIDED BY CONVERGENCE ALONG THE SEA
BREEZE. DCAPE VALUES ARE POOR, AS ARE LAPSE RATES, SO NOT
EXPECTING MUCH OF A SEVERE THREAT. WITH ELEVATED PWATS AND WEAK
STORM MOTION, HEAVY RAIN REMAINS THE PRIMARY THREAT WITH HIGH
RAIN RATES POSSIBLE. ACTIVITY SHOULD DIMINISH OVER THE NEXT FEW
HOURS. LITTLE CHANGE SUNDAY IN THE OVERALL PATTERN, ALTHOUGH
THE UPPER TROUGH AXIS WILL BE WEAKENING AS THE UPPER RIDGE TO
THE WEST BEGINS TO EXPAND EASTWARD. ISOLATED DIURNAL CONVECTION
REMAINS POSSIBLE GIVEN ABUNDANT ATMOSPHERIC MOISTURE IN PLACE.
KEY MESSAGE 2: WELL ABOVE NORMAL TEMPERATURES EXPECTED WITH
DANGEROUS HEAT INDEX VALUES POSSIBLE NEXT WEEK.
INCREASING CONFIDENCE IN A HOT AND HUMID START TO THE MONTH OF
SEPTEMBER. ENSEMBLES ARE IN GOOD AGREEMENT SHOWING AN ANOMALOUS
UPPER RIDGE GRADUALLY MIGRATING EASTWARD FROM THE MS VALLEY
EARLY IN THE WEEK TO THE APPALACHIANS AND CAROLINAS BY MID-LATE
WEEK. ESAT VALUES OF 500MB HEIGHTS ARE ABOVE THE 97TH PERCENTILE
MONDAY AND ABOVE THE 99TH PERCENTILE THROUGH MID WEEK AND
REMAINING ABOVE THE 90TH PERCENTILE THROUGH THE END OF THE WEEK.
THE STRONG UPPER RIDGING WILL CREATE STRONG SUBSIDENCE OVER THE
REGION WHICH SHOULD REALLY LIMIT CONVECTION MUCH OF THE WEEK.
THE RESULT SHOULD BE WELL ABOVE NORMAL TEMPERATURES AND THIS IS
SUPPORTED BY ENSEMBLE FORECAST TEMPERATURES AT 700/850/1000MB AT
OR ABOVE THE 99TH PERCENTILE WITH EC EFI VALUES FOR BOTH MAX
AND MIN TEMPERATURES IN THE 0.7-0.8 RANGE WITH NON-ZERO SHIFT OF
TAILS. HIGHS EXPECTED TO BE IN THE MID TO UPPER 90S WITH LOWS
IN THE LOWER TO MID 70S WITH LITTLE SPREAD AMONG THE NBM IQR.
THE COMBINATION OF ABOVE NORMAL TEMPERATURES AND INCREASED LOW
LEVEL MOISTURE WILL YIELD HIGH PROBABILITIES OF HEAT INDICES IN
THE 100-105 RANGE AND POSSIBLY HIGHER.
AVIATION /00Z SUNDAY THROUGH THURSDAY/
RESTRICTIONS LIKELY AGAIN TONIGHT AND SUNDAY MORNING.
GUIDANCE IS ONCE AGAIN SHOWING REDEVELOPMENT OF IFR RESTRICTIONS
TONIGHT AND EARLY SUNDAY MORNING. WINDS IN THE LOWER LEVELS WILL
BE LIGHT AND ABUNDANT LOW-LEVEL MOISTURE REMAINS IN PLACE. THIS
ADDS CONFIDENCE IN THE FORECAST FOR IFR CIGS. WE SHOULD SEE
CEILINGS LOWER AROUND 09Z, WITH VISIBILITY RESTRICTIONS
POSSIBLE AT ALL SITES AS WELL. CROSSOVER TEMPERATURES IN THE LOW
70S TO UPPER 60S WILL FAVOR AT LEAST BRIEF, PATCHY FOG BUT MID
AND HIGH LEVEL CLOUD COVER THROUGH THE NIGHT SHOULD HINDER
WIDESPREAD FOG. REGARDLESS, RESTRICTIONS ARE EXPECTED FROM IFR
TO MVFR AROUND 15Z THEN IMPROVING TO VFR AFTER 18Z. CONVECTIVE
COVERAGE ON SUNDAY IS EXPECTED TO BE LOWER THAN PREVIOUS DAYS SO
THE MENTION OF TS HAS BEEN OMITTED FOR NOW.
EXTENDED AVIATION OUTLOOK...DRIER CONDITIONS EXPECTED EARLY
NEXT WEEK, BUT BRIEF EARLY MORNING RESTRICTIONS STILL POSSIBLE.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...ND/23
AVIATION...CJR
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