979
FXUS62 KCAE 201802
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
202 PM EDT SUN SEP 20 2026
WHAT HAS CHANGED
PRECIPITATION CHANCES FOR DIURNALLY DRIVEN CONVECTION TODAY
HAVE DECREASED. AVIATION DISCUSSION UPDATED FOR 18Z TAFS.
KEY MESSAGES
- 1. ABOVE AVERAGE TEMPERATURES AND INCREASED CHANCES FOR
SHOWERS AND STORMS CONTINUE THROUGH TUESDAY.
- 2. RAIN EXPECTED ON WEDNESDAY, WITH COOLER AND DRIER
CONDITIONS LIKELY BY LATE WEEK AND NEXT WEEKEND.
DISCUSSION
KEY MESSAGE 1: ABOVE AVERAGE TEMPERATURES AND INCREASED CHANCES
FOR SHOWERS AND STORMS CONTINUE THROUGH TUESDAY.
CLEAR SKIES ARE DOMINANT ACROSS MOST OF THE AREA EARLY THIS
AFTERNOON. THE SETUP FOR CONVECTION TODAY IS A BIT WORSE THAN IT
WAS YESTERDAY, WITH THE BEST PWS AND INSTABILITY CONFINED TO THE
WESTERN MIDLANDS AND CSRA. AS A RESULT, REALLY NOT EXPECTING
COVERAGE THIS AFTERNOON. THIS WILL LIKELY CHANGE EARLY THIS
COMING WEEK AS THE OVERALL PATTERN BEGINS TO SHIFT. THE DOMINANT
RIDGING THAT WE HAVE GROWN ACCUSTOMED TO SINCE LAST WEEK WILL
BEGIN TO BREAK DOWN AND YIELD TROUGHING BY THE MIDDLE OF THE
WEEK. AT THE SAME TIME, A STRONG SURFACE HIGH PRESSURE MOVING
INTO SOUTHEASTERN CANADA WILL PUSH A BACKDOOR FRONT TOWARDS US
ON TUESDAY AND THEN WEDNESDAY. AHEAD OF THIS, COMPRESSIONAL
HEATING AND EARLY SUNSHINE SHOULD RESULT IN WELL ABOVE NORMAL
TEMPS BOTH MONDAY AND TUESDAY, WITH HIGHS FORECAST IN THE LOW TO
MID 90S. SCATTERED SHOWERS AND STORMS ARE EXPECTED ACROSS THE
AREA DURING THE AFTERNOON AND EVENING, WITH WIDESPREAD COVERAGE
PROBABLE BY TUESDAY EVENING AS FORCING IMPROVES.
KEY MESSAGE 2: RAIN EXPECTED ON WEDNESDAY, WITH COOLER AND
DRIER CONDITIONS LIKELY BY LATE WEEK AND NEXT WEEKEND.
LETS BE HONEST, WE HAVE ALL BEEN WAITING FOR THIS SPECIFIC
FORECAST FOR A WHILE NOW. ENSEMBLE AND OPERATIONAL MODELS ARE
FINALLY SHOWING A FAVORABLE SETUP FOR REASONABLE, FALL-LIKE
TEMPERATURES HERE IN SOUTH CAROLINA AND GEORGIA BEGINNING ON
WEDNESDAY. WE ARE LIKELY TO SEE WEDGE CONDITIONS DEVELOP BEHIND
THE BACKDOOR FRONT SOMETIME ON WEDNESDAY. THE TIMING AND
LOCATION OF THE FRONT DURING THE DAY ON WEDNESDAY IS UNCERTAIN,
AND THERE IS SOME SPREAD AMONGST THE GUIDANCE AS TO WHEN IT
PUSHES IN. THE NAM (SOON TO BE RETIRED BUT THE BEST AT CAD
SETUPS) IS THE MOST AGGRESSIVE WITH THE PASSAGE OF SAID BACKDOOR
FRONT, PUSHING IT SOUTH OF THE AREA BY WEDNESDAY AFTERNOON.
THAT SEEMS UNLIKELY BUT THERE IS A HIGH BUST POTENTIAL WITH
TEMPS WEDNESDAY AFTERNOON AS THE PLACEMENT OF THE FRONT WILL
DICTATE OUR TEMPS. BEYOND WEDNESDAY, THE WEATHER IS INCREASINGLY
LOOKING MORE PLEASANT. GUIDANCE IS IN GOOD AGREEMENT THAT DEEP
TROUGHING WILL OVERTAKE THE EASTERN US, LEADING TO NORTHWESTERLY
FLOW AND DRIER AIR OVER OUR AREA FROM THURSDAY INTO NEXT
WEEKEND. THE FIRST TASTE OF FALL IS EXPECTED, WITH HIGHS IN THE
UPPER 70S AND LOWER 80S AND LOWS IN THE UPPER 50S AND LOW 60S.
THIS FORECASTER COULD CRY TEARS OF JOY AT THIS.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
LOW CLOUDS AND PATCHY FOG THAT RESULTED IN MVFR CONDITIONS
DISSIPATED BY MID-MORNING AND HAVE GIVEN WAY TO FEW TO SCATTERED
CU EARLY THIS AFTERNOON AND LIGHT NORTHEASTERLY FLOW. A FEW
SHALLOW SHOWERS HAVE BEGUN TO DEVELOP NEAR AIK AND WEST OF AGS
AND DNL THIS HOUR, BUT COVERAGE THROUGH THIS AFTERNOON ACROSS
THE CSRA SHOULD BE LIMITED AND VIS RESTRICTIONS ARE UNLIKELY.
HAVE ELECTED TO LEAVE OUT PROB30 GROUPS HERE ACCORDINGLY.
ELSEWHERE, A TONGUE OF DRIER AIR ALOFT SHOULD SUPPRESS MOST DEEP
CONVECTION THIS AFTERNOON. TONIGHT, MOSTLY CALM CONDITIONS AND
CLEAR SKIES SHOULD FAVOR SOME GROUND FOG DEVELOPMENT AROUND
SUNRISE TOMORROW, PARTICULARLY SOUTH OF I-20. HAVE INCLUDED
TEMPO GROUPS FOR POTENTIAL IFR RESTRICTIONS AT OGB, AS GUIDANCE
FAVORS THE GREATEST FOG POTENTIAL ALONG THE COASTAL PLAIN,AND
HAVE NOTED MVFR AT ALL OTHERS. FOG SHOULD BURN OFF ALL TERMINALS
BY LATE MORNING WITH DIURNAL HEATING.
EXTENDED AVIATION OUTLOOK...CHANCES FOR SHOWERS AND/OR THUNDERSTORMS
WILL CONTINUE THROUGH INTO MID-WEEK, WITH THE BEST CHANCES ON
TUESDAY AND WEDNESDAY. MORNING CIG/VIS RESTRICTIONS WILL REMAIN
POSSIBLE.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...PL
AVIATION...SF
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