695
FXUS62 KCAE 281824
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
224 PM EDT TUE APR 28 2026
WHAT HAS CHANGED
LOWERED TODAY'S HIGH TEMPERATURES WITH SHOWERS AND CLOUD COVER
KEEPING TEMPERATURES COOLER THAN NBM VALUES. ADDITIONAL DETAILS
ON A LOW THREAT OF SEVERE WEATHER WEDNESDAY AFTERNOON. UPDATED
AVIATION DISCUSSION FOR 18Z TAFS.
KEY MESSAGES
- 1. ROUNDS OF RAIN THROUGH MID-WEEK, SEVERE THUNDERSTORMS ARE
POSSIBLE WEDNESDAY AFTERNOON BUT CONFIDENCE IS LOW.
- 2. CONFIDENCE INCREASING IN MODERATE RAINFALL FOR PORTIONS OF
THE FORECAST AREA FRIDAY NIGHT AND SATURDAY.
DISCUSSION
KEY MESSAGE 1: ROUNDS OF RAIN THROUGH MID-WEEK, SEVERE THUNDERSTORMS
ARE POSSIBLE WEDNESDAY AFTERNOON BUT CONFIDENCE IS LOW.
WITH UPPER RIDGING FLATTENING OVER THE SOUTHEAST WE WILL SEE SEVERAL
ROUNDS OF SHORTWAVE TROUGHS ROLL OVER THE RIDGE AND INTO THE
FORECAST AREA THROUGH THURSDAY. A COLD FRONT WILL ALSO WORK ACROSS
THE SOUTHEAST WEDNESDAY THROUGH THURSDAY PROVIDING SOME ENHANCED
CONVERGENCE FOR CONVECTION UPSTREAM. THE TIMING OF THE CONVECTION
THAT WORKS INTO THE FORECAST AREA EACH DAY SHOULD BE SIMILAR TO
TUESDAY MORNING WITH DECAYING THUNDERSTORMS FROM THE PREVIOUS DAY
PERSISTING DUE TO THE ENHANCEMENT FROM SHORTWAVE ENERGY.
THE MOST ACTIVE DAY FOR OUR AREA WILL BE WEDNESDAY WHEN DEEPER
MOISTURE WILL BE OVER THE AREA. EXPECT WIDESPREAD SHOWERS TO
CROSS THROUGH THE FORECAST AREA WEDNESDAY MORNING. CAMS INDICATE
THE WEAKENING CONVECTION SHOULD LIMIT THE EXTENT OF THUNDER BUT
WE SHOULD SEE AT LEAST ISOLATED TO SCATTERED THUNDERSTORMS IN
THE MORNING WITH MUCAPE VALUES BELOW 500 J/KG. NO SEVERE WEATHER
IS EXPECTED THROUGH THE MORNING. TOTAL RAIN AMOUNTS WILL
LARGELY DEPEND ON HOW MUCH OF THE DEEPER CONVECTION CAN HOLD
TOGETHER BUT IN GENERAL WE SHOULD SEE AROUND A QUARTER OF AN
INCH OF RAIN WITH LOCALLY HIGHER AMOUNTS IN TALLER CELLS.
WEDNESDAY AFTERNOON, THERE IS A LOW THREAT OF SEVERE WEATHER WITH
THE MAIN THREAT LOCATED IN THE PEE DEE AND CATAWBA. AS THE COLD
FRONT APPROACHES THE FORECAST AREA FROM THE NORTH, WE MAY SEE
ADDITIONAL CONVECTION DEVELOP AHEAD OF THE BOUNDARY. THERE IS A
QUESTION OF WHETHER WE WILL SEE THE AIR MASS DESTABILIZE AS MODELS
SHOW, BUT IF SO THE 35 TO 45 KTS OF DEEP LAYER (0-6KM) SHEAR SHOULD
ALLOW FOR ORGANIZED THUNDERSTORMS TO DEVELOP. MEAN SBCAPE VALUES
FROM THE HREF AND REFS ARE GENERALLY AROUND 1000 J/KG IN THE PEE DEE
AND CATAWBA. LOW LEVEL SRH (0-1KM) VALUES ALSO APPROACH 100 M2/S2
WITH STP AT 0.8 TO 1.0 IN THESE AREAS. ULTIMATELY THE THREAT OF
SEVERE WEATHER WILL LARGELY DEPEND ON HOW QUICKLY/IF WE BREAK
OUT OF THE CLOUD COVER FOLLOWING SHOWERS IN THE MORNING. IF
DESTABILIZATION OCCURS THERE WILL BE POTENTIAL FOR ORGANIZED
THUNDERSTORMS WITH HAZARDS OF HAIL AND DAMAGING WINDS. WE ALSO
CANNOT RULE OUT A TORNADO THREAT.
KEY MESSAGE 2: CONFIDENCE INCREASING IN MODERATE RAINFALL FOR
PORTIONS OF THE FORECAST AREA FRIDAY NIGHT AND SATURDAY.
ENSEMBLES CONTINUE TO FAVOR BROAD TROUGHING OVER THE EASTERN HALF OF
THE US FROM LATE WEEK AND INTO THE WEEKEND. NAEFS IVT PERCENTILES
HAVE INCREASED TO 99.5 OF CLIMATOLOGY, WITH HIGHEST VALUES IN THE
SOUTHERN PORTION OF THE FORECAST AREA. THIS INDICATES THE POTENTIAL
FOR A PERIOD OF MODERATE TO HEAVY RAINFALL FROM LATE FRIDAY THROUGH
SATURDAY. MODELS ARE STARTING TO COME INTO BETTER AGREEMENT WITH THE
TIMING OF THE RAINFALL AND TRACK OF THE LOW ACROSS THE
SOUTHEAST. THAT HAS LED TO A JUMP IN PROBABILITIES FOR MODERATE
RAINFALL. THE 25TH PERCENTILE FROM THE NBM IS NOW UP TO 0.25 TO
0.5 INCHES FOR AREAS SOUTH OF I-20 WITH MEANS CLOSER TO 1 TO
1.5 INCHES AREA WIDE (FRIDAY NIGHT THROUGH SATURDAY TOTALS).
AVIATION /18Z TUESDAY THROUGH SUNDAY/
GENERALLY VFR CONDITIONS INTO TONIGHT. ANOTHER ROUND OF
RESTRICTIONS POSSIBLE EARLY WEDNESDAY.
THE LAST OF THE RAIN SHOWERS, BUT SOME LINGERING IFR CEILINGS
ARE MOVING OVER THE TERMINALS AT THE START OF THE TAF PERIOD.
EXPECT BROKEN CEILINGS, BUT GENERALLY VFR THE REST OF THE
AFTERNOON WITH SOUTH TO SOUTHWEST WINDS BETWEEN 5-10 KTS.
OVERNIGHT, WINDS BECOME LIGHT AND VARIABLE AS VFR CIGS CONTINUE.
ANOTHER SYSTEM APPROACHES THE AREA LATE TONIGHT, WITH
RESTRICTIONS ANTICIPATED TO MOVE IN DURING THE 08Z-10Z
TIMEFRAME. SHOWER ACTIVITY IS ALSO EXPECTED TO MOVE IN DURING
THIS TIME, SO HAVE ADDED A TEMPO GROUP TO ACCOUNT FOR THIS.
ALTHOUGH UNLIKELY, THERE COULD BE AN EMBEDDED THUNDERSTORM OR
TWO WITH THIS ACTIVITY LIKE WE SAW TODAY. AFTER THE SHOWERS MOVE
OUT, WINDS ARE FORECAST TO PICK UP OUT OF THE SOUTHWEST,
GUSTING TO 15-20 KTS AT TIMES.
EXTENDED AVIATION OUTLOOK...PERIODS OF RESTRICTIONS ARE
POSSIBLE LATE THIS WEEK INTO THE WEEKEND WITH MORE RAIN CHANCES.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...CJR
AVIATION...29
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