645
FXUS62 KCAE 211039
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
639 AM EDT MON SEP 21 2026
WHAT HAS CHANGED
AVIATION DISCUSSION UPDATED FOR 12Z 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.
THE OVERALL PATTERN BEGINS TO SHIFT EARLY THIS WEEK, AS THE
DOMINANT RIDGING THAT HAS PREVAILED GRADUALLY BREAKS DOWN AND
GIVES WAY TO TROUGHING BY MIDWEEK. IN THE MEANTIME, TODAY WILL
REMAIN SEASONABLY HOT AND HUMID, WITH TUESDAY LIKELY TO CONTINUE
RUNNING ABOVE AVERAGE AS HIGHS REACH THE LOW TO MID 90S. A FEW
POP- UP SHOWERS COULD DEVELOP LATER THIS AFTERNOON, WITH
SCATTERED SHOWERS AND THUNDERSTORMS EXPECTED TO BECOME MORE
WIDESPREAD TUESDAY. COVERAGE SHOULD INCREASE THROUGH TUESDAY
AFTERNOON AND EVENING AS FORCING IMPROVES, WITH A STRONG
SURFACE HIGH BUILDING ACROSS SOUTHEASTERN CANADA HELPING TO
DRIVE A BACKDOOR FRONT SOUTHWARD INTO THE AREA INTO WEDNESDAY.
THIS WILL MARK THE BEGINNING OF A TRANSITION TOWARD A COOLER AND
DRIER PATTERN BY MID TO LATE WEEK.
KEY MESSAGE 2: RAIN EXPECTED ON WEDNESDAY, WITH COOLER AND
DRIER CONDITIONS LIKELY BY LATE WEEK AND NEXT WEEKEND.
ENSEMBLE AND OPERATIONAL GUIDANCE ARE FINALLY SHOWING A
FAVORABLE PATTERN FOR MORE REASONABLE, FALL-LIKE TEMPERATURES
ACROSS OUR AREA BEGINNING WEDNESDAY. SOME UNCERTAINTY REMAINS AS
A BLOCKING PATTERN ACROSS THE NORTHERN PLAINS SHIFTS EASTWARD.
PATTERN CHANGES OF THIS MAGNITUDE OFTEN PRODUCE UNCERTAINTY
REGARDING THE EVENTUAL PLACEMENT AND EVOLUTION OF THE UPPER-
LEVEL AND SURFACE LOWS. REGARDLESS, GUIDANCE INCREASINGLY
SUPPORTS THE DEVELOPMENT OF A WEDGE BEHIND THE FRONT SOMETIME
WEDNESDAY. THE NAM REMAINS THE MOST AGGRESSIVE, BRINGING THE
FRONT SOUTH OF THE AREA BY WEDNESDAY AFTERNOON. THIS SCENARIO
APPEARS SOMEWHAT UNLIKELY AT THIS TIME, BUT THERE REMAINS A
RELATIVELY HIGH BUST POTENTIAL FOR TEMPERATURES WEDNESDAY
AFTERNOON AS THE EXACT POSITION AND TIMING OF THE FRONT WILL
HAVE A SIGNIFICANT IMPACT ON TEMPERATURES ACROSS THE AREA.
BEYOND THAT, THE FORECAST INCREASINGLY TRENDS TOWARD MORE
PLEASANT CONDITIONS. GUIDANCE IS IN GOOD AGREEMENT THAT DEEP
TROUGHING WILL BECOME ESTABLISHED ACROSS THE EASTERN CONUS,
RESULTING IN NORTHWESTERLY FLOW AND DRY AIR ACROSS THE REGION
FROM THURSDAY INTO THE WEEKEND. HIGHS SHOULD GENERALLY FALL 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 /12Z MONDAY THROUGH FRIDAY/
PATCHY FG AND AREAS OF BR POSSIBLE THIS MORNING.
SATELLITE CONTINUES TO SHOW THIN CIRRUS ACROSS THE MAJORITY OF
THE AREA, ALONG WITH SOME DEVELOPING LOWER VISIBILITIES AND
CEILING RESTRICTIONS IN AREAS THAT HAVE CLEARED OUT MORE THIS
MORNING. APPEARS TO BE A HIGHER LIKELIHOOD OF IFR RESTRICTIONS
AT FOG PRONE AGS, OGB, AND EVEN AIK. MVFR VISIBILITY RESTRICTIONS
ARE MORE LIKELY AT THE OTHER SITES. HAVE CONTINUED THE TEMPO
GROUPS AT ALL SITES, BUT EXTENDED IT THROUGH 14Z. RESTRICTIONS
SHOULD LIFT BY 14 OR 15Z. ISOLATED THUNDERSTORMS ARE POSSIBLE
AGAIN DURING THE AFTERNOON, HOWEVER COVERAGE IS EXPECTED TO BE
TOO LOW TO BE INCLUDED IN THE TAFS AT THIS TIME. LATE TONIGHT
AND INTO TUESDAY MORNING, ANOTHER ROUND OF VISIBILITY AND
CEILING RESTRICTIONS WILL REMAIN POSSIBLE AT ALL SITES.
EXTENDED AVIATION OUTLOOK...RAIN CHANCES AND WIDESPREAD
RESTRICTIONS ARE MOST LIKELY TUESDAY THROUGH THURSDAY AS
MOISTURE ADVECTION INCREASES AND WEDGE CONDITIONS DEVELOP.
SEASONAL, EARLY MORNING CIG/VIS RESTRICTIONS WILL REMAIN
POSSIBLE EARLY THIS WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
AVIATION...73
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