277
FXUS62 KCAE 221923
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
ISSUED BY NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
323 PM EDT WED APR 22 2026
WHAT HAS CHANGED
SMOKE AND ITS IMPACTS TO VISIBILITY WERE ADDED TO THE FORECAST.
KEY MESSAGES
- 1. ELEVATED FIRE WEATHER CONCERNS AND PERIODIC SMOKE IMPACTS
WILL PERSIST THROUGH FRIDAY.
- 2. RAIN CHANCES INCREASE THIS WEEKEND INTO EARLY NEXT WEEK,
BUT MEANINGFUL DROUGHT RELIEF REMAINS UNCERTAIN.
DISCUSSION
KEY MESSAGE 1: ELEVATED FIRE WEATHER CONCERNS AND PERIODIC
SMOKE IMPACTS WILL PERSIST THROUGH FRIDAY.
DRY CONDITIONS WILL CONTINUE TO SUPPORT ELEVATED FIRE DANGER
THROUGH FRIDAY, INCLUDING THE REMAINDER OF THIS AFTERNOON. THE
MAIN DRIVERS WILL BE LOW RH VALUES AND DRY FUELS WITHIN THE
ONGOING SEVERE TO EXTREME DROUGHT ACROSS THE REGION. MINIMUM RH
VALUES ARE BOTTOMING OUT IN THE UPPER TEENS AND LOWER 20S
ACROSS THE PEE DEE AND IN THE MID 20S ACROSS THE MIDLANDS AND
CSRA THIS AFTERNOON. SIMILAR MIN RH VALUES ARE EXPECTED AGAIN
THURSDAY AFTERNOON. FRIDAY'S HUMIDITY FORECAST IS A BIT LESS
CERTAIN AND WILL DEPEND ON HOW QUICKLY SOUTHWEST RETURN FLOW
STRENGTHENS AROUND THE RETREATING BERMUDA RIDGE. IF MOISTURE
RECOVERY IS SLOWER THAN CURRENTLY EXPECTED, MINIMUM RH VALUES
FRIDAY AFTERNOON COULD END UP VERY SIMILAR TO THOSE OBSERVED
TODAY AND FORECAST FOR THURSDAY.
TO ACCOUNT FOR THE RECENT TENDENCY OF THE NBM TO RUN TOO MOIST
IN THIS DRY PATTERN, AFTERNOON DEWPOINTS WERE TRENDED LOWER
USING A BLEND WEIGHTED TOWARD THE NBM 5TH PERCENTILE FOR TODAY,
THURSDAY, AND FRIDAY. WINDS SHOULD REMAIN LIGHT ENOUGH TO
PRECLUDE A MORE CRITICAL FIRE WEATHER SETUP THROUGH THE END OF
THE WEEK, WITH WEST TO SOUTHWEST WINDS GENERALLY 5 TO 10 MPH AND
OCCASIONAL GUSTS TO AROUND 15 MPH THIS AFTERNOON AND AGAIN
FRIDAY. EVEN LIGHTER WINDS ARE EXPECTED THURSDAY AS THE PRESSURE
GRADIENT WEAKENS ALONG THE WESTERN PERIPHERY OF THE BERMUDA
RIDGE. DESPITE THE LACK OF STRONGER WINDS, THE COMBINATION OF
LOW RH AND DRY FUELS WILL MAINTAIN ELEVATED FIRE DANGER EACH
AFTERNOON. THE SOUTH CAROLINA FORESTRY COMMISSION BURN BAN
REMAINS IN EFFECT UNTIL FURTHER NOTICE.
IN ADDITION, SMOKE FROM ONGOING WILDFIRES ACROSS SOUTHERN GEORGIA
WILL CONTINUE TO SPREAD NORTHEASTWARD INTO THE REGION ON
SOUTHWEST FLOW THROUGH AT LEAST FRIDAY. THE GREATEST SMOKE
IMPACTS ARE EXPECTED ACROSS THE CSRA AND WESTERN MIDLANDS,
WHERE PERIODIC REDUCTIONS IN VISIBILITY AND DEGRADED AIR QUALITY
ARE POSSIBLE. SMOKE CONCENTRATIONS MAY FLUCTUATE OVER SHORT
TIME SCALES, BUT THIS WILL REMAIN AN ADDITIONAL IMPACT OF THE
BROADER DRY PATTERN THROUGH THE END OF THE WORK WEEK. SMOKE WAS
ADDED TO THE FORECAST GRIDS THROUGH THURSDAY, AND WILL LIKELY
BE NEEDED FOR FRIDAY ONCE THE DETAILS BECOME CLEARER. AN AIR
QUALITY ALERT WAS ISSUED FOR MOST OF OUR SC ZONES EXCEPT THE
NORTHERN PEE DEE AND CATAWBA/CHARLOTTE REGIONS.
KEY MESSAGE 2: RAIN CHANCES INCREASE THIS WEEKEND INTO EARLY
NEXT WEEK, BUT MEANINGFUL DROUGHT RELIEF REMAINS UNCERTAIN.
THE FIRST OPPORTUNITY FOR MUCH NEEDED RAINFALL ARRIVES WITH A
COLD FRONT SATURDAY AFTERNOON AND NIGHT, FOLLOWED BY ANOTHER
FRONTAL PASSAGE AROUND TUESDAY. WHILE BOTH SYSTEMS SHOULD BRING
SCATTERED TO NUMEROUS SHOWERS AND PERHAPS A FEW THUNDERSTORMS,
CURRENT PROBABILISTIC GUIDANCE SUGGESTS THE POTENTIAL FOR
WIDESPREAD MEANINGFUL RAINFALL REMAINS LIMITED OR AT LEAST
UNCLEAR.
FOR SATURDAY AFTERNOON THROUGH SATURDAY NIGHT, NBM PROBABILITIES
OF 24 HOUR RAINFALL EXCEEDING ONE HALF INCH ARE GENERALLY ONLY
20 TO 30 PERCENT. PROBABILITIES OF EXCEEDING ONE INCH ARE BELOW
15 PERCENT. THE 24-HOUR PROBABILISTIC QPF DISTRIBUTION FOR THE
SATURDAY EVENT ALSO HIGHLIGHTS THE UNCERTAINTY AND OVERALL
LIMITED UPSIDE FOR WIDESPREAD HEAVIER RAINFALL.
A SIMILAR STORY HOLDS FOR TUESDAY, WHEN NBM PROBABILITIES FOR
RAINFALL EXCEEDING 0.5 INCH ARE AGAIN ONLY AROUND 20 TO 30
PERCENT, WHILE PROBABILITIES OF EXCEEDING 1 INCH REMAIN BELOW
20 PERCENT.
INSTABILITY ALSO APPEARS LIMITED ENOUGH TO TEMPER CONFIDENCE IN
STRONGER THUNDERSTORM DEVELOPMENT, ESPECIALLY ON SATURDAY. NBM
PROBABILISTIC SBCAPE FOR SATURDAY AFTERNOON SHOWS 50TH
PERCENTILE VALUES ONLY AROUND 200 TO 400 J/KG, WITH THE 90TH
PERCENTILE AROUND 600 TO 900 J/KG. TUESDAY APPEARS SOMEWHAT MORE
UNSTABLE, WITH SBCAPE 50TH PERCENTILE VALUES AROUND 750 TO 1000
J/KG AND 90TH PERCENTILE VALUES AROUND 900 TO 1400 J/KG, BUT
EVEN THEN THE SIGNAL IS NOT ESPECIALLY IMPRESSIVE FOR LATE
APRIL.
GIVEN THE CURRENT DROUGHT, ANY RAINFALL WILL BE BENEFICIAL, AND
SOME LOCATIONS COULD STILL PICK UP LOCALLY MEANINGFUL AMOUNTS.
HOWEVER, THE PROBABILISTIC GUIDANCE CONTINUES TO SUPPORT A
MESSAGE OF LIMITED AND UNEVEN RAINFALL RATHER THAN WIDESPREAD
DROUGHT RELIEF.
AVIATION /19Z WEDNESDAY THROUGH MONDAY/
THE PRIMARY AVIATION CONCERN THROUGH THE TAF PERIOD WILL BE
REDUCED VISIBILITY DUE TO SMOKE FROM ONGOING WILDFIRES ACROSS
SOUTHERN AND CENTRAL GA. SMOKE IS BEING ADVECTED NORTHEASTWARD
INTO THE REGION, WITH THE GREATEST IMPACTS EXPECTED AT TERMINALS
ALONG AND SOUTH OF THE I-20 CORRIDOR, INCLUDING KAGS AND KCAE.
VISIBILITY REDUCTIONS TO 3-5 SM HAVE ALREADY BEEN OBSERVED AT
TIMES TODAY, AND SMOKE IS EXPECTED TO PERSIST ACROSS THE AREA
THROUGH TONIGHT AND INTO THURSDAY. HIRES GUIDANCE FROM THE HRRR
SMOKE MODEL SUGGESTS ANOTHER SURGE OF DENSE NEAR-SURFACE SMOKE
MAY MOVE INTO THE REGION FROM THE WILDFIRES BETWEEN ROUGHLY 07Z
AND 11Z. CONFIDENCE IN THE MAGNITUDE OF ANY ADDITIONAL
VISIBILITY REDUCTIONS REMAINS UNCERTAIN, BUT PERIODIC
RESTRICTIONS BELOW VFR ARE POSSIBLE.
GIVEN THE VARIABILITY IN SMOKE CONCENTRATIONS, VISIBILITY
FORECASTS MAY REQUIRE FREQUENT UPDATES TO REFLECT SHORT-TERM
TRENDS OVER THE NEXT 1-2 DAYS.
EXTENDED AVIATION OUTLOOK...PERIODS OF VISIBILITY RESTRICTIONS
DUE TO SMOKE ARE LIKELY TO PERSIST THROUGH AT LEAST FRIDAY AS
SOUTHWEST FLOW CONTINUES TO TRANSPORT SMOKE INTO THE REGION.
OTHERWISE, DRY CONDITIONS SHOULD LIMIT FOG DEVELOPMENT. RAIN
CHANCES INCREASE THIS WEEKEND, WHICH MAY INTRODUCE RESTRICTIONS
AT TIMES, THOUGH CONFIDENCE IN TIMING AND COVERAGE REMAIN LOW.
CAE WATCHES/WARNINGS/ADVISORIES
SC...AIR QUALITY ALERT UNTIL 8 PM EDT THURSDAY FOR SCZ018-020>022-
025>031-035-037-038-041-135>137.
GA...NONE.
DISCUSSION...JRK
AVIATION...JRK
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