690
FXUS62 KCAE 212357
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
757 PM EDT MON SEP 21 2026
WHAT HAS CHANGED
AVIATION DISCUSSION UPDATED FOR 00Z TAFS.
KEY MESSAGES
- 1. ABOVE AVERAGE TEMPERATURES AND CHANCES FOR SHOWERS AND STORMS
EARLY THIS WEEK.
- 2. MUCH COOLER CONDITIONS EXPECTED WEDNESDAY ONWARD, WITH
PERIODS OF SHOWERS MAINLY WEDNESDAY AND THURSDAY.
DISCUSSION
KEY MESSAGE 1: ABOVE AVERAGE TEMPERATURES AND CHANCES FOR SHOWERS
AND STORMS EARLY THIS WEEK.
ONE MORE DAY OF A STAGNANT PATTERN TODAY WITH A SHIFT BEGINNING
LATE TUESDAY. UPPER LOW OVER NORTHWEST FLORIDA WILL CONTINUE TO
DRAW MOISTURE INTO THE STATE OVER THE NEXT 24 HOURS. THIS
DISTURBANCE SHOULD FINALLY LIFT NORTHEAST OFF OUR COASTLINE
TUESDAY IN RESPONSE TO AN APPROACHING UPPER TROUGH MOVING
THROUGH THE MIDWEST. HIGHS TODAY WILL STILL PEAK IN THE LOW 90S
WITH ISOLATED SHOWERS AND THUNDERSTORMS AS A RESULT OF THE
STRONG HEATING. BETTER COVERAGE OF PRECIP CAN BE ANTICIPATED
TUESDAY AS BETTER FORCING ASSOCIATED WITH THE UPPER LOW GRAZES
THE FORECAST AREA. ANOTHER SHORTWAVE MOVES ACROSS THE REGION
FROM THE WEST WHILE A SURFACE FRONT MOVES SOUTH THEN SINK ACROSS
THE MIDLANDS TUESDAY NIGHT WITH SCATTERED TO WIDESPREAD SHOWERS
AND STORMS.
KEY MESSAGE 2: MUCH COOLER CONDITIONS EXPECTED WEDNESDAY ONWARD,
WITH PERIODS OF SHOWERS MAINLY WEDNESDAY AND THURSDAY.
MODELS ARE GENERALLY CONVERGING NOW HIGH PRESSURE OVER THE NORTHEAST
WILL PUSH A WEDGE FRONT THROUGH OUR FORECAST AREA LATE TUESDAY INTO
WEDNESDAY. THE ONGOING SHOWERS AND CLOUD COVER WEDNESDAY MORNING
WILL LIKELY LIMIT DAYTIME HEATING, ESPECIALLY WITH COLD ADVECTION
OCCURRING AT THE SURFACE. THERE REMAINS SOME UNCERTAINTY REGARDING
HOW FAR SOUTH THE WEDGE FRONT WILL GO, AND IT IS EXPECTED TO HAVE A
TIGHT TEMPERATURE GRADIENT SETTING UP SOMEWHERE ACROSS THE SOUTHERN
MIDLANDS WEDNESDAY AFTERNOON. ALL SAID, THE TEMPERATURE DROP OF 10
TO 15+ DEGREES BETWEEN TUESDAY AND WEDNESDAY WILL BE VERY NOTICEABLE
NORTH OF THE FRONT. THERE WILL ALSO BE SOME BREEZY NORTHEAST WINDS
ACCOMPANYING THIS AIRMASS CHANGE. BLENDED GUIDANCE STRUGGLES IN
THESE SCENARIOS AND SO NAM/GFS DATA WAS BLENDED IN AND COLLABORATED
TO BETTER CAPTURE THE EXPECTED TEMPERATURES. IT CAN BE NOTED THAT WE
MAY STILL BE TOO WARM FOR THURSDAY, AND FUTURE PACKAGES MAY CONTINUE
TO DROP TEMPERATURES AS APPROPRIATE.
AN UPPER TROUGH THURSDAY WILL WORK TO SCOUR OUT THE WEDGE THROUGH
SOME PORTION OF THE DAY, WITH DRIER NORTHWEST FLOW EVENTUALLY MOVING
INTO THE AREA. HIGH PRESSURE WILL CONTINUE TO BE IN PLACE AT THE
SURFACE AND KEEP TEMPERATURES ON THE COOLER SIDE. BUT THE DRIER AIR
ALOFT WILL BRING PRECIP-FREE CONDITIONS BACK BY FRIDAY WITH HIGHS
STARTING TO REBOUND BACK A BIT CLOSER TO NORMAL. HIGHS SHOULD
GENERALLY REACH INTO THE UPPER 70S AND LOW 80S, WITH OVERNIGHT LOWS
IN THE UPPER 50S TO LOW 60S. OVERALL, THIS SHOULD PROVIDE OUR FIRST
REAL TASTE OF FALL WITH A REFRESHING CHANGE IN TEMPERATURES ARRIVING
JUST AS ASTRONOMICAL AUTUMN BEGINS ON TUESDAY!
AVIATION /00Z TUESDAY THROUGH SATURDAY/
FOG POSSIBLE TUESDAY MORNING, SCATTERED THUNDERSTORMS EXPECTED
IN THE AFTERNOON.
ALTHOUGH MODELS ARE AGAIN SUGGESTING FOG DEVELOPMENT TONIGHT,
BASED ON THE VERIFICATION FROM THE PAST FEW DAYS IT SEEMS
UNLIKELY THAT WIDESPREAD IFR FOG WILL DEVELOP. THEREFORE WE
TRENDED THE TAFS TOWARDS A MORE OPTIMISTIC OUTLOOK LIMITING MVFR
FOG TO THE FOG PRONE SITES AGS AND OGB BETWEEN 9Z AND 12Z
SIMILAR TO WHAT OCCURRED THE PREVIOUS MORNING.
EAST WINDS WILL PICK UP AROUND 7 KTS AFTER 15Z TUESDAY. THE
ENVIRONMENT WILL SUPPORT HIGHER CONVECTIVE COVERAGE IN THE
AFTERNOON WITH SCATTERED THUNDERSTORMS EXPECTED TO DEVELOP
AROUND 18Z. THUNDERSTORMS ARE LIKELY TO CONTINUE INTO THE
EVENING PAST THE END OF THE 00Z TAF PERIOD.
EXTENDED AVIATION OUTLOOK...WIDESPREAD RESTRICTIONS AND HIGHER
RAIN CHANCES EXPECTED EARLY WEDNESDAY THROUGH THURSDAY AS WEDGE
CONDITIONS SET UP ACROSS THE REGION. DRIER CONDITIONS EXPECTED
BEGINNING FRIDAY.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...ND
AVIATION...CJR
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