732
FXUS62 KCAE 291709
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
109 PM EDT MON JUN 29 2026
WHAT HAS CHANGED
ISOLATED STRONG TO SEVERE STORMS POSSIBLE THIS AFTERNOON AND
EVENING. CONTINUED TO HIGHLIGHT INCREASING HEAT LATE THIS WEEK
INTO THE HOLIDAY WEEKEND. AVIATION DISCUSSION UPDATED FOR THE
18Z TAFS.
KEY MESSAGES
- 1. INCREASED THREAT OF IMPACTFUL HEAT THIS WEEK AND INTO THE
INDEPENDENCE DAY WEEKEND.
- 2. ISOLATED TO SCATTERED CONVECTION EXPECTED THIS AFTERNOON INTO
EARLY EVENING.
DISCUSSION
KEY MESSAGE 1: INCREASED THREAT OF IMPACTFUL HEAT THIS WEEK AND
INTO THE INDEPENDENCE DAY WEEKEND.
A STRONG UPPER RIDGE CENTERED OVER THE TN VALLEY AND LOWER MS
VALLEY TODAY WILL MIGRATE SLOWLY NORTHEASTWARD INTO THE OH
VALLEY BY MID WEEK AND THEN BECOME CENTERED OVER THE MID-
ATLANTIC BY THE END OF THE WEEK. THIS 500MB HIGH IS ANOMALOUSLY
STRONG WITH HEIGHTS AT OR ABOVE THE 99TH PERCENTILE RELATIVE TO
CLIMATOLOGY. TEMPERATURES TODAY SHOULD PUSH INTO THE MID AND
UPPER 90S WITH DEWPOINTS IN THE LOWER 70S RESULTING IN HEAT
INDICES OVER 100 DEGREES. HEAT INDICES LIKELY PUSH OVER 105
DEGREES IN PARTS OF THE CSRA WHERE MOISTURE WILL BE POOLING
ALONG THE WEAK STALLED FRONTAL BOUNDARY AND A HEAT ADVISORY WAS
CONSIDERED BUT EXPECTED SCATTERED CONVECTION LED TO LOW
CONFIDENCE.
AS THE UPPER RIDGE BUILDS CLOSER TO THE REGION TEMPERATURES
SHOULD BE WARMING FURTHER WITH HIGHS IN THE UPPER 90S TO AROUND
100 DEGREES FOR THE HOLIDAY WEEKEND. ENSEMBLES INDICATE HIGHLY
ANOMALOUS 850MB TEMPERATURES OVER THE 90TH PERCENTILE AND ECMWF
EFI ALSO SHOWING ANOMALOUS SIGNALS IN THE MAX TEMPERATURE
FIELD.
ENSEMBLES INDICATE LOWERING ATMOSPHERIC MOISTURE THROUGH MID TO
LATE WEEK WITH PWATS FALLING BELOW 50 PERCENT OF NORMAL
SUPPORTING A GENERALLY DRY FORECAST WHEN COMBINED WITH THE
STRONG SUBSIDENCE OF THE UPPER RIDGE. THIS SHOULD ALSO RESULT IN
BETTER DEEP MIXING AND LOWER DEWPOINTS AND THEREFORE LOWER HEAT
INDICES MID TO LATE WEEK DESPITE THE INCREASING TEMPERATURES.
MOISTURE RETURNS TO THE REGION OVER THE WEEKEND AND LIKELY WILL
YIELD HEAT INDICES NEAR HEAT ADVISORY CRITERIA WHICH MAY RESULT
IN THE NEED FOR SOME HEAT PRODUCTS. REGARDLESS, THROUGHOUT THE
ENTIRE WEEK AND FORECAST PERIOD ANYONE SPENDING A SIGNIFICANT
AMOUNT OF TIME OUTSIDE SHOULD TAKE NECESSARY PRECAUTIONS TO
HANDLE THE HEAT AND STAY HYDRATED. BE SURE TO MAKE HEAT SAFETY
PREPARATIONS NOW AND HAVE A PLAN TO MONITOR CHILDREN, THE
ELDERLY, PETS, AND ANYONE WITHOUT ADEQUATE INDOOR COOLING.
KEY MESSAGE 2: ISOLATED TO SCATTERED CONVECTION EXPECTED THIS
AFTERNOON INTO EARLY EVENING.
ISOLATED TO SCATTERED CONVECTION IS EXPECTED TO DEVELOP IN AN
INCREASINGLY UNSTABLE ENVIRONMENT GENERALLY WEST OF I-26
CORRIDOR IN THE VICINITY OF A STALLED FRONTAL BOUNDARY OVER THE
CSRA. MLCAPE VALUES ALREADY PUSHING AT OR ABOVE 2000 J/KG IN THE
CSRA WITHIN AN AXIS OF MAXIMUM PWATS OF 1.8-1.9 INCHES WITH
20-25 KNOTS OF SHEAR EXPECTED LATER THIS AFTERNOON WHICH MAY
SUPPORT A FEW STRONG TO SEVERE STORMS. DCAPE VALUES ARE
MAXIMIZED IN THE CSRA AT AROUND 1200 J/KG SO DAMAGING WIND GUSTS
WOULD BE THE PRIMARY THREAT ASSOCIATED WITH THE STRONGEST
STORMS. HI-RES GUIDANCE GENERALLY SHOWS SOME DEVELOPMENT
ALTHOUGH DIFFERING ON TIMING OF INITIATION, BUT STORMS EXPECTED
TO DEVELOP UPSTREAM OVER WESTERN NC AND THE SC UPSTATE AND SHIFT
SOUTHWARD IN THE NORTHERLY FLOW ALOFT.
AVIATION /18Z MONDAY THROUGH SATURDAY/
VFR CONDITIONS LIKELY WITH AN OUTSIDE CHANCE FOR ISOLATED SHOWERS-
STORMS.
A WEAK BOUNDARY WILL CONTINUE SAGGING TOWARD THE GA/SC BORDER
THIS AFTERNOON AS DRIER AIR FILTERS INTO THE REGION. WINDS HAVE
SHIFTED OUT OF THE NORTH-NORTHEAST AROUND 5-7 KT. SOME
THUNDERSTORMS ARE STILL POSSIBLE AT AGS-DNL THIS AFTERNOON AS
THE BOUNDARY LINGERS NEARBY DURING PEAK HEATING. CONFIDENCE
REMAINS LOW IN DIRECT IMPACTS TO TERMINALS, SO A PROB30 HAS BEEN
MAINTAINED FROM 19-23Z. THIS WILL NEED TO BE MONITORED ONCE WE
HAVE A BETTER IDEA WHERE STORMS HAVE DEVELOPED.
ACTIVITY WILL DIMINISH AFTER SUNSET, LEAVING MOSTLY CLEAR SKIES
AND LIGHT WINDS. DRY CONDITIONS CONTINUE TUESDAY AS HIGH
PRESSURE BUILDS INTO THE AREA.
EXTENDED AVIATION OUTLOOK...AFTERNOON CONVECTION IS LESS LIKELY
FOR THE REMAINDER OF THE WEEK AS RIDGING BUILDS OVERHEAD. BRIEF
EARLY MORNING RESTRICTIONS ALSO POSSIBLE THIS WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...23
AVIATION...ND
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