171
FXUS62 KCAE 121710
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
110 PM EDT SUN JUL 12 2026
WHAT HAS CHANGED
UPDATED MESOANALYSIS FOR STORMS EXPECTED THIS AFTERNOON.
ADJUSTED WORDING OF KEY MESSAGES. AVIATION DISCUSSION UPDATED
FOR 18Z TAFS.
KEY MESSAGES
- 1. SCATTERED STORMS EXPECTED AGAIN THIS AFTERNOON AND EVENING
WITH DAMAGING WIND GUSTS AND HEAVY RAIN EXPECTED. LINGERING
MOISTURE LEADING TO SCATTERED TO WIDESPREAD AFTERNOON STORMS
MONDAY THROUGH WEDNESDAY.
DISCUSSION
KEY MESSAGE 1: SCATTERED STORMS EXPECTED AGAIN THIS AFTERNOON
AND EVENING WITH DAMAGING WIND GUSTS AND HEAVY RAIN EXPECTED.
LINGERING MOISTURE LEADING TO SCATTERED TO WIDESPREAD AFTERNOON
STORMS MONDAY THROUGH WEDNESDAY.
EARLY THIS AFTERNOON, CONVECTION HAS TAKEN A BIT LONGER TO GET
GOING COMPARED TO YESTERDAY, MAINLY DUE TO THE INCREASED
CLOUDINESS AND A BIT LONGER TIME FOR US TO REACH CONVECTIVE
TEMPERATURES TODAY. AS MOST SITES ARE STARTING TO RISE INTO THE
LOW 90S BY 1PM, CONVECTIVE TEMPERATURES ARE BECOMING REACHED AND
AS A RESULT, BEGINNING TO SEE SOME AGITATION TO THE CLOUDS AND
SOME CONVECTION DEVELOPING IN THE AREA. THIS ACTIVITY IS
EXPECTED TO CONTINUE TO GROW THROUGH THE AFTERNOON AND INTO THIS
EVENING AS A ROBUST SHORTWAVE IS CURRENTLY MOVING INTO THE
TENNESSEE VALLEY WITH A SURFACE FRONT MOVING INTO SOUTHERN NC.
THIS PROVIDE ADDITIONAL FORCING WITH RAP FORECAST SOUNDINGS
INDICATING STRONG DESTABILIZATION TODAY WITH SBCAPE AROUND 3000
J/KG FOR MUCH OF THE FORECAST AREA, SIMILAR TO THE LAST COUPLE
OF DAYS. WHILE PWATS ARE CURRENTLY AROUND 2 INCHES, ESPECIALLY
ACROSS THE NORTHERN AREA, A LAYER OF MID LAYER DRY AIR IS
VISIBLE ON WATER VAPOR SATELLITE IMAGERY FROM NORTH GEORGIA
SHIFTING INTO THE AREA, WHICH WILL LIKELY LEAD TO A LOCALLY
ENHANCED AREA FAVORABLE FOR STRONG TO SEVERE DOWNBURSTS LEADING
TO DAMAGING WIND GUSTS. STORMS MAY BECOME A BIT MORE ORGANIZED
THIS AFTERNOON AS WELL WITH A BIT STRONGER DEEP LAYER SHEAR,
AROUND 20 KNOTS, WHICH SUPPORT MULTICELL CLUSTERS DEVELOPING AND
MAINTAINING THROUGH THE FORECAST AREA. WHILE STORMS SHOULD
EXHIBIT SUFFICIENT MOVEMENT TO PREVENT WIDESPREAD FLOODING, WILL
NEED TO MONITOR TRAINING STORMS WITH AREAS GENERALLY NORTH OF
I-20 (AND AUGUSTA AND COLUMBIA METROS) MORE SUSCEPTIBLE TO
FLOODING DUE BOTH TO THE SOIL TYPE AND RAINFALL RECEIVED THE
LAST COUPLE DAYS.
ON MONDAY, THE FRONT IS EXPECTED TO MOVE THROUGH AND THE MID
LEVEL LOW SHOULD DROP INTO THE REGION AS HIRES GUIDANCE
INDICATES PWAT'S APPROACH 2.2 INCHES. LOW LEVEL FLOW BECOMES
INCREASINGLY NORTHERLY TO NORTHEASTERLY, KEEPING TEMPERATURES A
BIT COOLER AND INCREASED CLOUD COVER IS EXPECTED TO LIMIT
DESTABILIZATION. THIS BRINGS A LOWER RISK FOR SEVERE WEATHER
WITH MORE MARGINAL THERMODYNAMICS, BUT A COUPLE STRONG TO
MARGINALLY SEVERE STORMS CANNOT BE RULED OUT DURING THE
AFTERNOON/EVENING AS DEEP LAYER SHEAR IS SLIGHTLY INCREASED. THE
BIGGER RISK MONDAY MAY BE THE HEAVY RAINFALL RISK AS SCATTERED
TO WIDESPREAD SHOWERS AND STORMS MOVE THROUGH THE AREA DURING
THE DAY WITH EFFICIENT RAIN RATES, SIMILAR TO SLIGHTLY HIGHER
THAN SUNDAY IN THIS MOIST AIRMASS. THE HIGHEST CONCERN WILL
CONTINUE TO BE IN AREAS HIGHLIGHTED TODAY ALONG WITH AREAS THAT
RECEIVED ADDITIONAL SIGNIFICANT RAINFALL TODAY.
SHOWER AND THUNDERSTORMS WILL LIKELY CONTINUE TUESDAY AND
WEDNESDAY AND ENSEMBLE MEANS HAVE BEEN SLOWER TO BRING IN A
DRIER AIR MASS WITH PWATS GENERALLY GREATER THAN A STANDARD
DEVIATION ABOVE NORMAL FOR AT LEAST PORTIONS OF THE AREA THROUGH
WEDNESDAY, ALTHOUGH DRIER AIR LIKELY STARTS TO SNEAK INTO THE
NORTHERN AREA ON WEDNESDAY. COOLER AIR MASS GENERALLY EXPECTED
TO CONTINUE EARLY THIS WEEK WITH A RECOVERY EXPECTED TO NORMAL
OR SLIGHTLY ABOVE NORMAL TEMPERATURES FOR THE SECOND HALF OF THE
WEEK AS THE UPPER RIDGE CENTERED OVER THE CENTRAL CONUS BEGINS
TO SHIFT EASTWARD.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
VFR CONDITIONS EXPECTED FOR MOST OF THE PERIOD, WITH THE
EXCEPTION OF CONVECTION THIS AFTERNOON AND POTENTIALLY CEILINGS
LATER ON TONIGHT.
A MORE ORGANIZED AND ROBUST FORCING MECHANISM IS WORKING
TOWARDS THE AREA TODAY. A TROUGH WILL FORCE A WEAK SURFACE LOW
ON THE LEE SIDE OF THE APPALACHIANS THIS AFTERNOON, HELPING TO
FOCUS CONVECTIVE DEVELOPMENT ACROSS THE CAROLINAS. THE
ENVIRONMENT IS FAVORABLE FOR NUMEROUS, STRONG DOWNBURSTS AGAIN.
GIVEN THE EXPECTED COVERAGE OF SHOWERS/STORMS, HAVE KEPT VCTS AT
ALL SITES THROUGH THIS EVENING & BUMPED UP THE WIND AT EACH
SITE IN THE PROB30S. GIVEN THE ENVIRONMENT IN PLACE, IT WOULD
NOT BE SURPRISING TO SEE 35-45 KNOT GUSTS AT THE SITES IN
STRONGER STORMS THIS AFTERNOON. EXPECTING THE CONVECTION TO
PERSIST INTO THE EVENING AS THE SURFACE FRONT APPROACHES AND
PUSHES THROUGH THE FORECAST AREA. NORTHEASTERLY FLOW BEHIND
THIS, COMBINED WITH VERY RICH LOW-LEVEL MOISTURE, SHOULD RESULT
IN MVFR CEILINGS DEVELOPING AND PERSISTING THROUGH THE END OF
THE PERIOD. THE LAMP IS DELAYING THE CIGS UNTIL 11Z-13Z, WITH
THE NBM A BIT MORE AGGRESSIVE (~06Z). THINKING THAT THE LATTER
IS PROBABLY A BIT MORE REALISTIC AS THE CONVECTION TODAY WILL
LIKELY RESULT IN THE SURFACE FRONT SINKING SOUTHWARD A BIT
QUICKER THAN MODELS CAN ANTICIPATE. SO BRING MVFR CIGS INTO THE
SITES BETWEEN 08Z AND 09Z - BUT IT COULD BE EARLIER OR A BIT
LATER.
EXTENDED AVIATION OUTLOOK...A GOOD CHANCE FOR AFTERNOON SHOWERS
AND THUNDERSTORMS WITH ASSOCIATED RESTRICTIONS IS EXPECTED INTO
EARLY NEXT WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...96
AVIATION...PL
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