614
FXUS62 KCAE 041033
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
633 AM EDT FRI SEP 4 2026
WHAT HAS CHANGED
A HEAT ADVISORY WILL BE IN EFFECT FROM 11AM TO 8PM FOR
CHESTERFIELD AND LANCASTER COUNTIES TODAY. UNCERTAINTY REMAINS
IN CONVECTIVE COVERAGE AND TIMING SATURDAY. AVIATION DISCUSSION
UPDATED FOR 06Z TAF ISSUANCE.
KEY MESSAGES
- 1. HEAT ADVISORY IN EFFECT FROM 11AM UNTIL 8PM FOR LANCASTER
AND CHESTERFIELD COUNTIES TODAY.
- 2. HEAT INDEX VALUES FROM 105 TO 110 POSSIBLE SATURDAY.
- 3. SEVERE STORMS POSSIBLE SATURDAY AFTERNOON OR EVENING.
DISCUSSION
KEY MESSAGE 1. HEAT ADVISORY IN EFFECT FROM 11AM UNTIL 8PM FOR
LANCASTER AND CHESTERFIELD COUNTIES TODAY.
THE RIDGE WILL SLOWLY BEGIN TO RETROGRADE THROUGH THE DAY
TODAY, BUT 850MB TEMPERATURES NEAR THE NAEFS 99TH PERCENTILE AND
ROBUST HEATING SHOULD ONCE AGAIN YIELD TEMPERATURES IN THE MID
TO UPPER 90S. DEWPOINTS ARE EXPECTED TO MIX OUT AGAIN TOWARD THE
LOW 70S, BUT A FEW LOCATIONS COULD STICK TOWARD THE MID 70S.
OVERALL, THIS SHOULD YIELD HEAT INDICES BETWEEN 105-108. A FEW
AREAS NEAR CHESTERFIELD AND LANCASTER COUNTIES COULD BRIEFLY
REACH HEAT ADVISORY CRITERIA AND DUE TO THIS, A HEAT ADVISORY
WILL BE IN EFFECT TODAY FROM 11AM UNTIL 8PM THIS EVENING FOR
THESE COUNTIES.
KEY MESSAGE 2. HEAT INDEX VALUES FROM 105 TO 110 POSSIBLE
SATURDAY.
THE FORECAST REMAINS ON TRACK WITH THE UPPER RIDGE EXPECTED TO
RETROGRADE THROUGH THE DAY SATURDAY AS A FAIRLY STRONG TROUGH
DIGS INTO THE EASTERN US. THIS SHOULD BRING NORTHWESTERLY
DOWNSLOPING FLOW THAT WILL AID IN BRINGING TEMPERATURES INTO THE
UPPER 90S DESPITE THE RIDGE MOVING WESTWARD. MOISTURE IS ALSO
EXPECTED TO SLIGHTLY INCREASE AHEAD OF A FRONT MOVING IN FROM
THE NORTH THROUGH THE DAY WHERE SURFACE DEWPOINTS COULD STICK
TOWARD THE MID 70S FOR MUCH OF THE AREA, THOUGH DEEPER MIXING
MAY AID IN LOWERING THESE SLIGHTLY. OVERALL, HEAT INDICES
BETWEEN 105-110 COULD BE POSSIBLE SATURDAY AFTERNOON AND THE
NEED FOR A HEAT ADVISORY WILL CONTINUE TO BE MONITORED. BESIDES
THE POTENTIAL FOR SLIGHTLY LOWER DEWPOINTS FROM MIXING, ANY
CONVECTION THAT COULD DEVELOP EARLIER IN THE AFTERNOON WOULD
THROW A WRENCH IN THIS. THE 00Z SUITE OF MODELS CONTINUES TO
FAVOR ANY CONVECTION HOLDING OFF UNTIL LATER IN THE DAY AT THIS
TIME HOWEVER, WHICH IS REASONABLE AS THE UPPER WAVE AND FRONT
ARE NOT PROGGED TO NEAR UNTIL THEN. EITHER WAY, ANOTHER
HOT/HUMID DAY IS EXPECTED AND HEAT SAFETY WILL NEED TO BE
EXERCISED WITH ANY OUTDOOR ACTIVITIES.
KEY MESSAGE 3. SEVERE STORMS POSSIBLE SATURDAY AFTERNOON OR
EVENING.
THE 00Z SUITE OF GUIDANCE REMAINS FAIRLY INSISTENT THAT THE
MAJORITY OF CONVECTION IS EXPECTED TO HOLD OFF UNTIL THE LATE
AFTERNOON TO EARLY EVENING HOURS SATURDAY AS SEEN IN THE MEAN
HREF SOLUTION. THE COLD FRONT AND SHORTWAVE MENTIONED IN KEY
MESSAGE 2 ARE EXPECTED TO SPARK CONVECTION NORTH OF THE CWA
THROUGH THE DAY THAT SHOULD PERSIST IN THE STRONGLY UNSTABLE AND
MOISTURE RICH ENVIRONMENT. THE DEGREE IN WHICH THIS ACTIVITY
HOLDS TOGETHER AS IT MOVES TOWARD THE FA REMAINS UNCERTAIN
DEPENDING ON TIMING, BUT MLCAPE VALUES ON THE ORDER OF 2500 J/KG
SHOULD BE IN PLACE WITH STEEP LOW LEVEL LAPSE RATES AND AROUND
20-25 KTS OF EFFECTIVE SHEAR. THESE PARAMETERS SUGGEST A
DAMAGING WIND THREAT COULD BE SEEN AS CONVECTION PUSHES IN,
ESPECIALLY TOWARD THE NORTHERN FA AND THE PEE DEE WITH GREATER
UNCERTAINTY FURTHER SOUTH. A FEW INSTANCES OF SUB-SEVERE HAIL
CANNOT BE RULED OUT EITHER GIVEN LARGE CAPE PROFILES IN THE HAIL
GROWTH ZONE AND SOME MID-LEVEL DRY AIR. OVERALL, TIMING TRENDS
WILL NEED TO BE MONITORED, BUT AN ISOLATED SEVERE THREAT IS
POSSIBLE GIVEN THE ENVIRONMENT.
THE COLD FRONT IS FORECAST TO REMAIN NEAR THE REGION ON SUNDAY
SO WE CAN EXPECT AT LEAST A CHANCE OF SHOWERS AND THUNDERSTORMS
WITH MOISTURE STILL IN PLACE AND SOME SHORTWAVE ACTIVITY
ROUNDING THE BASE OF THE TROUGH. THE TROUGH IS EXPECTED TO
PERSIST INTO EARLY NEXT WEEK, BRINGING TEMPERATURES CLOSER TO
NORMAL AND AT LEAST ISOLATED DIURNAL RAIN CHANCES BEFORE GLOBAL
MODELS AND ENSEMBLE GUIDANCE INDICATE THE RIDGE TO OUR WEST
SHOULD SLOWLY WORK BACK IN. THIS SHOULD BRING BACK DRIER
CONDITIONS AND WARMING TEMPERATURES.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
SUNRISE STRATUS-FOG DEVELOPING ACROSS THE AREA, PERIODIC
RESTRICTIONS LIKELY THIS MORNING.
ACROSS EASTERN GA AND CENTRAL SC, STRATUS-FOG IS DEVELOPING AS
OF 6AM. IMPACTS TO TERMINALS ARE EXPECTED TO BE PERIODIC THROUGH
13Z FOR ALL TERMINALS. CONFIDENCE IS LOW IN LIFR RESTRICTIONS
BUT A MIX OF MVFR AND IFR IS POSSIBLE, VSBY AND CIGS. THIS WILL
STEADILY CLEAR OUT AFTER 13Z AND ANOTHER TYPICAL SUMMER DAY IS
EXPECTED. CU FIELD DEVELOPS BY LATER MORNING AND A FEW AFTERNOON
STORMS AROUND, BUT VERY CHANCE FOR TERMINAL IMPACTS TODAY.
WINDS WILL STEADILY SHIFT FROM SOUTHEAST TO SOUTHERLY THROUGHOUT
THE AFTERNOON.
EXTENDED AVIATION OUTLOOK...CHANCES FOR RESTRICTIONS AND
THUNDERSTORMS INCREASE SATURDAY AFTERNOON AND SUNDAY AS A COLD
FRONT APPROACHES.
CAE WATCHES/WARNINGS/ADVISORIES
SC...HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING
FOR SCZ016-115-116.
GA...NONE.
DISCUSSION...DH
AVIATION...42
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