488
FXUS62 KCAE 221824
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
224 PM EDT TUE SEP 22 2026
WHAT HAS CHANGED
KEY MESSAGE 1 UPDATED TO REFLECT RECENT RADAR TRENDS AND MODEL
GUIDANCE. AVIATION DISCUSSION UPDATED FOR 18Z TAFS.
KEY MESSAGES
- 1. WARM AND HUMID WITH SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND EVENING.
- 2. COOLER CONDITIONS EXPECTED WEDNESDAY ONWARD, WITH PERIODS
OF SHOWERS MAINLY WEDNESDAY AND THURSDAY.
DISCUSSION
KEY MESSAGE 1: WARM AND HUMID WITH SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS THIS AFTERNOON AND EVENING.
MIDDAY RADAR IMAGERY SHOWS CONVECTION QUICKLY DEVELOPING ACROSS
THE SOUTHWESTERN MIDLANDS AND CSRA. WHILE LATEST MESOANALYSIS
DATA SHOWS CAPE VALUES BETWEEN 1500 AND 2500 J/KG, DCAPE VALUES
ARE ONLY BETWEEN 500 AND 750 J/KG IMPLYING A LOWER RISK FOR
DOWNBURST WINDS. SPC MAINTAINS A MARGINAL (1/5) RISK FOR SEVERE
WEATHER, MAINLY NORTH AND WEST OF I-20 TODAY. AS IS TYPICALLY
THE CASE WHEN AN INVERTED-V PROFILE DEVELOPS, ANY ROBUST
THUNDERSTORM WILL BE CAPABLE OF PRODUCING GUSTY WINDS. THE MORE
LIKELY WEATHER HAZARD TODAY SHOULD BE FROM THE HEAVY RAINFALL,
WHICH MAY LEAD TO LOCALIZED FLASH FLOODING. THE LATEST WPC ERO
PLACES LOCATIONS NORTH AND WEST OF I-20 IN A SLIGHT (2/4) RISK
FOR EXCESSIVE RAINFALL, WITH A MARGINAL (1/4) RISK ELSEWHERE.
LONG, SKINNY CAPE PROFILES IN MODELED SOUNDINGS AND PWATS
BETWEEN 1.8 AND 2 INCHES SUPPORT THIS THREAT. THE LATEST SOIL
MOISTURE ANALYSIS SHOWS THE HIGHEST VALUES ACROSS NEWBERRY AND
NORTHERN SALUDA COUNTIES AND ITS THESE AREAS THAT HAVE SOME OF
THE LOWEST FFG VALUES IN THE FA AND THEREFORE THE REGIONS OF
GREATEST CONCERN FOR FLASH FLOODING, OUTSIDE OF NORMALLY PRONE
LOCATIONS. IN TERMS OF TEMPERATURES, ONE MORE WARM AND HUMID DAY
IS ONGOING WITH FORECAST HIGHS IN THE UPPER 80S AND LOWER 90S.
KEY MESSAGE 2: COOLER CONDITIONS EXPECTED WEDNESDAY ONWARD, WITH
PERIODS OF SHOWERS MAINLY WEDNESDAY AND THURSDAY.
MODELS ARE GENERALLY CONVERGING ON HIGH PRESSURE OVER THE
NORTHEAST PUSHING THE WEDGE FRONT THROUGH OUR FORECAST AREA
LATE TONIGHT 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, SO WE HAVE BEEN USING THE NAM/GFS
MODELS TO BETTER CAPTURE THE EXPECTED TEMPERATURES LATE THIS
WEEK.
ADDITIONAL CLOUD COVER AND PRECIP SUGGESTS THURSDAY COULD BE OUR
COOLEST DAY OF THE WEEK FOR HIGH TEMPERATURES, WITH MOST EXPECTED TO
REMAIN IN THE LOW TO UPPER 70S. AN UPPER TROUGH WILL WORK TO SCOUR
OUT THE WEDGE THROUGH SOME PORTION OF THE DAY, WITH DRIER NORTHWEST
FLOW EVENTUALLY MOVING IN. HIGHS WILL REBOUND A BIT CLOSER TO NORMAL
AS PRECIP AND CLOUD FREE CONDITIONS RETURN FRIDAY AND INTO THIS
WEEKEND. HIGHS WILL GENERALLY REACH THE UPPER 70S TO 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 OFFICIALLY BEGINS
LATER TODAY!
AVIATION /18Z TUESDAY THROUGH SUNDAY/
SCATTERED THUNDERSTORMS EXPECTED THIS AFTERNOON AND EVENING.
CEILING RESTRICTIONS BEGINNING TONIGHT INTO TOMORROW MORNING.
WHILE THE SURFACE FRONT REMAINS NORTH OF THE FORECAST AREA AND
WILL PUSH SOUTHWARD BY LATE TONIGHT, SCATTERED SHOWERS AND
THUNDERSTORMS ARE HAVE DEVELOPED (EARLIER THAN FORECAST BY
GUIDANCE AGAIN) ACROSS THE FORECAST AREA EARLY THIS AFTERNOON.
THUNDERSTORMS PUSHING SOUTH THROUGH AGS AND DNL IN THE PAST HOUR
HAVE ALREADY PRODUCED LOWERED VIS DOWN TO 2 1/2SM AND GUSTS UP
TO 30KT. HAVE MAINTAINED VCTS THROUGH ALL TERMINALS THROUGH
00Z, WITH TEMPOS NOW THROUGH 22-23Z FOR TSRA. THUNDERSTORM
ACTIVITY SHOULD WIND DOWN AND BECOME STEADY -RA WITH LATE THIS
EVENING INTO VERY EARLY THIS MORNING AS THE WEDGE FRONT
APPROACHES. GUIDANCE REMAINS CONSISTENT INTO DEVELOPING CEILING
RESTRICTIONS WITH A STRATUS DECK FROM NORTH TO SOUTH, GENERALLY
WITH MVFR CEILINGS STARTING AROUND 03-05Z, THEN IFR CONDITIONS
DEVELOPING BY 06Z-08Z. SOME UNCERTAINTY REMAINS REGARDING HOW
FAR SOUTH THE WEDGE WILL SETTLE IN BY WEDNESDAY MORNING, BUT
IFR CEILINGS WILL LIKELY LINGER THROUGH THE MORNING ACROSS MOST
OF THE MIDLANDS, WHILE AREAS FARTHER SOUTH AT AGS, DNL AND OGB
ARE MORE LIKELY TO SEE CEILINGS LIFT INTO MVFR CONDITIONS BY
LATE MORNING.
AS FOR WINDS, EASTERLY TO NORTHEASTERLY WINDS AT 5-8 KTS HAVE
DEVELOPED THIS AFTERNOON OUTSIDE SHOWERS AND THUNDERSTORMS.
WINDS SHOULD WEAKEN SLIGHTLY AND SHIFT TO NORTHEASTERLY LATE
THIS EVENING, THEN PICK UP SLIGHTLY TO 5-10 KT LIKELY AFTER 06Z
AS THE COLD FRONT PUSHES INTO THE AREA.
EXTENDED AVIATION OUTLOOK...WIDESPREAD RESTRICTIONS AND
CONTINUED RAIN CHANCES EXPECTED WEDNESDAY THROUGH THURSDAY AS
WEDGE CONDITIONS SETTLE ACROSS THE REGION. DRIER CONDITIONS
EXPECTED BEGINNING FRIDAY.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...7
AVIATION...SF
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