900
FXUS62 KCAE 291922
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
322 PM EDT SAT MAR 29 2025
SYNOPSIS
MOISTURE IS INCREASING TODAY, WITH RAIN CHANCES INTO SUNDAY
MORNING. SHOWERS AND THUNDERSTORMS LIKELY SUNDAY AFTERNOON WITH
HEAVY RAIN POSSIBLE. WIDESPREAD RAIN AND THUNDERSTORMS EXPECTED
ON MONDAY AFTERNOON AHEAD OF A COLD FRONT. SEVERE THUNDERSTORMS
WILL BE POSSIBLE MONDAY AFTERNOON. WELL ABOVE NORMAL
TEMPERATURES EXPECTED FOR LATE WEEK.
NEAR TERM /UNTIL 6 AM SUNDAY MORNING/
KEY MESSAGE(S):
- LESSENED FIRE DANGER WITH INCREASING HUMIDITIES.
- RAIN CHANCES MOVE IN LATE AND INTO SUNDAY.
MOISTURE CONTINUES TO INCREASE ACROSS THE REGION THIS AFTERNOON
AS THE WEAKENING UPPER TROUGH OVER THE LOWER MS VALLEY
CONTINUES TO NEAR THE FA WITH PWAT'S SITTING AT 0.90" AS
SOUTHERLY TO SOUTHEASTERLY FLOW ALSO AIDS IN SOME WARM ADVECTION
AND THE DEVELOPMENT OF A CUMULUS DECK ACROSS THE FA. THERE IS
ALSO INCREASING HIGH CLOUDS AS WELL WITH THE APPROACHING TROUGH
BUT WARM ADVECTION IS ALLOWING TEMPERATURES TO BE ON TRACK TO
REACH THE UPPER 70S TO NEAR 80 AGAIN THIS AFTERNOON. THE UPPER
TROUGH WILL MOVE INTO THE REGION TONIGHT AND INTO SUNDAY MORNING
WHERE DEEPER/STRONGER ISENTROPIC LIFT SETS UP, ESPECIALLY AFTER
4-6 AM SUNDAY, ALONG WITH AT LEAST SOME WEAK VORTICITY
ADVECTION WITH THE UPPER TROUGH AS PWAT'S RAISE TO BETWEEN
1.30-1.45" AND SOUTHERLY FLOW AT 925 MB INCREASES TO 25-30 KTS.
THIS WILL LEAD TO SOME ISOLATED RAIN SHOWER CHANCES STARTING
DURING THIS TIME FRAME BUT ANY POTENTIAL THUNDERSTORMS LOOK TO
HOLD OFF UNTIL LATER SUNDAY. WITH THE EXPECTED CLOUD COVER
CONTINUING AND INCREASING MOISTURE TONIGHT, LOWS WILL BE LIMITED
TO THE UPPER 50S TO NEAR 60.
SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/
KEY MESSAGE(S):
- SHOWERS AND THUNDERSTORMS EXPECTED SUNDAY AFTERNOON.
- SEVERE WEATHER POSSIBLE ON MONDAY AFTERNOON
SUNDAY AND SUNDAY NIGHT: HIGH PRESSURE OVER THE ATLANTIC WILL
LEAD TO MOIST, SOUTHERLY FLOW OVER THE SOUTHEAST. MOISTURE WILL
INCREASE THROUGH THE DAY WITH MEAN PWAT VALUES FROM THE HREF
AROUND 1.5 INCHES IN THE AFTERNOON (ABOUT 0.5 TO 0.75 INCHES
HIGHER THAN THE PREVIOUS 24 HRS). AS THE ATMOSPHERE DESTABILIZES
THROUGH DAYTIME HEATING A WEAK SHORTWAVE WILL MOVE OVER THE
FORECAST AREA. THIS WILL ALLOW WIDESPREAD SHOWERS THUNDERSTORMS
TO DEVELOP IN THE CONDITIONALLY UNSTABLE AIR MASS. HOWEVER CAPE
VALUES WILL BE WEAK WITH MIXED LAYER CAPE VALUES OF NEAR OR LESS
THAN 750 J/KG ON SUNDAY AFTERNOON. WEAK CAPE AND WEAK SHEAR
WILL LIMIT THE THREAT OF SEVERE WEATHER. HEAVY RAIN MAY BE THE
PRIMARY THREAT GIVEN PWAT VALUES FROM THE NAEFS AROUND THE 97.5
PERCENTILE OF THE CLIMATOLOGICAL DATASET. STORM MOTION SHOULD BE
RELATIVELY FAST THOUGH KEEPING THE THREAT OF FLASH FLOODING
ISOLATED TO MAINLY URBAN AREAS. THE HIGHEST RAIN CHANCES ARE BE
IN THE CSRA AND WESTERN MIDLANDS WHERE MOISTURE IS DEEPER. THE
SHORTWAVE WILL MOVE EAST OF THE AREA DURING THE EVENING WHICH,
ALONG WITH LOSS OF HEATING, SHOULD ALLOW THUNDERSTORM COVERAGE
TO DIMINISH AFTER SUNSET. THERE MAY BE A FEW LINGERING SHOWERS
SUNDAY NIGHT WITH CONTINUED MOISTURE ADVECTION AHEAD OF MONDAY'S
COLD FRONT. WARM ADVECTION WILL PUSH HIGHS FOR SUNDAY INTO THE
UPPER 70S TO LOW 80S WITH MILD LOWS OVERNIGHT AROUND 60 DEGREES.
MONDAY AND MONDAY NIGHT: A SHORTWAVE TROUGH WILL MOVE ACROSS
THE CENTRAL US AND INTO THE EASTERN US. THIS WILL DRIVE A COLD
FRONT THROUGH THE SOUTHEAST ON MONDAY. A LINE OF CONVECTION IS
EXPECTED TO BE ONGOING MONDAY MORNING WELL WEST OF THE FA. AHEAD
OF THE FRONT AND CONVECTION WE WILL SEE WARM ADVECTION AND
DAYTIME HEATING LEAD TO A MODERATELY DESTABILIZED AIR MASS OVER
THE FORECAST AREA. MIXED LAYER CAPE VALUES GENERALLY RANGE FROM
1000 TO 1500 J/KG IN THE DETERMINISTIC AND SPC SREF
MODELS/MEMBERS HOWEVER THERE IS SOME POTENTIAL FOR MLCAPE ABOVE
1500 J/KG. AS THE LINE OF SHOWERS AND THUNDERSTORMS MOVE INTO
WARM THETA-E AIR WE WOULD EXPECT TO SEE CONVECTION STRENGTHEN. A
40 TO 50 KT 850 MB JET WILL SUPPORT SOME ORGANIZED CELL
STRUCTURES EMBEDDED WITHIN THE LINE OF CONVECTION. THIS
COMBINATION OF MODERATE SHEAR, MODERATE INSTABILITY, AND NEAR
CLIMATOLOGICAL MAX MOISTURE AHEAD OF A COLD FRONT ALL POINT TO
WIDESPREAD RAINFALL AND SOME POTENTIAL FOR SEVERE WEATHER. THE
BIGGEST THREAT MAY BE DAMAGING WINDS ALONG THE LINE OF
THUNDERSTORMS, ALTHOUGH A FEW STORMS COULD PRODUCE LARGE HAIL OR
A TORNADO. THE MAIN FORECAST CHALLENGE WILL BE THE NORTHERN
EXTENT OF THE MOST UNSTABLE AIR MASS. IT IS POSSIBLE THAT THE
STRONGEST STORMS REMAIN SOUTH OF THE FA. HIGHS ON MONDAY WILL
LIKELY BE IN THE UPPER 70S OR LOWER 80S. THE RAIN THREAT SHOULD
QUICKLY SHIFT EASTWARD ON MONDAY NIGHT AS DRIER AND COOLER AIR
FILTERS IN BEHIND THE COLD FRONT.
LONG TERM /TUESDAY THROUGH SATURDAY/
KEY MESSAGE(S):
- NEAR RECORD TEMPERATURES POSSIBLE AT THE END OF THE LONG TERM
FORECAST GUIDANCE REMAINS CONSISTENT FOR THE LONG TERM PERIOD.
SURFACE HIGH PRESSURE AND TROUGHING ARE EXPECTED TO PASS THROUGH
THE REGION ON TUESDAY IN THE WAKE OF THE COLD FRONTAL PASSAGE.
GLOBAL ENSEMBLES FAVOR SIGNIFICANT HEIGHT RISES THROUGH MID WEEK
INTO THE WEEKEND WITH SOUTHERLY FLOW RETURNING. A BLOCKING
PATTERN SETS UP MID WEEK RESULTING IN AN ANOMALOUSLY STRONG MID-
LEVEL RIDGE ACROSS THE SOUTHEASTERN CONUS PERSISTING INTO THE
WEEKEND. AS A RESULT, CONFIDENCE IS BEGINNING TO INCREASE IN A
PERIOD OF NEAR RECORD HIGHS IN THE THUR-SAT PERIOD OF THIS LONG
TERM FORECAST. ABNORMALLY HIGH HEIGHTS AND STRONG SUBSIDENCE
BENEATH THE RIDGE FAVOR WELL ABOVE NORMAL TEMPS.
THE HIGHEST RAIN CHANCES OF THE LONG TERM WILL BE MID-WEEK
BEFORE THE RIDGE SETS UP OVER THE AREA. MULTIPLE SHORTWAVES ARE
EXPECTED TO MOVE OVER THE RIDGE TO THE EAST. PWAT VALUES AROUND
1.25 TO 1.5 INCHES, SHORTWAVE ACTIVITY, AND WEAK RIDGING FOR
WEDNESDAY AND THURSDAY SUPPORT A SLIGHT TO LOW CHANCE OF RAIN.
AVIATION /20Z SATURDAY THROUGH THURSDAY/
VFR CONDITIONS CONTINUE TO PERSIST BEFORE EXPECTED STRATUS
DEVELOPMENT INTO SUNDAY MORNING, BRINGING POSSIBLE MVFR TO IFR
RESTRICTIONS ALONG WITH INCREASING RAIN SHOWER CHANCES INTO
SUNDAY AFTERNOON.
THE UPPER DISTURBANCE OVER THE MS VALLEY WILL LIFT ACROSS THE
REGION TONIGHT BUT BEFORE THIS, 5-12 KT SOUTHERLY TO
SOUTHEASTERLY WINDS HAVE CONTINUED TO INCREASE MOISTURE AS A
SCATTERED TO BROKEN CUMULUS DECK BETWEEN 4,000 TO 5,500 FT HAS
DEVELOPED ACROSS ALL SITES WITH CONTINUED PASSING HIGH CLOUDS.
THIS CONTINUES INTO THE EVENING BEFORE THE CUMULUS DECK BEGINS
TO DISSIPATE BUT MID TO HIGH LEVEL CLOUDS CONTINUE TO STREAM IN
AHEAD OF THE UPPER DISTURBANCE. WINDS BECOME LIGHT AND VARIABLE
OVERNIGHT WHERE 25-30 KTS OF FLOW AROUND 2,000 FT IS POSSIBLE
BUT HAVE LEFT LLWS OUT OF THE TAF AT THIS TIME AS THE
EXPECTATION IS FOR MOST LOCATIONS TO KEEP SOME LIGHT WINDS
OVERNIGHT. MODELED SOUNDINGS CONTINUE TO SHOW A SIGNAL FOR
POTENTIAL STRATUS DEVELOPMENT AFTER 9-11Z SUNDAY, LEADING TO
MVFR AND POSSIBLE IFR RESTRICTIONS WHERE PROBABILITIES FOR THIS
ARE BETWEEN 40-60 PERCENT. THIS DECK SLOWLY LIFTS TOWARD THE
END OF THE PERIOD BEFORE RAIN SHOWER CHANCES INCREASE AS WELL,
BUT HAVE LEFT OUT MENTION OF THUNDERSTORMS IN THE TAF AT THIS
TIME AS ANY POTENTIAL FOR THIS SEEMS TO COME JUST AFTER THE
CURRENT PERIOD.
EXTENDED AVIATION OUTLOOK...MORE RESTRICTIONS WILL BE POSSIBLE
MONDAY AS MORE RAIN CHANCES ACCOMPANY A PASSING COLD FRONT.
FIRE WEATHER
THE SOUTH CAROLINA FORESTRY COMMISSION HAS ISSUED A STATEWIDE
BURN BAN UNTIL FURTHER NOTICE.
MOISTURE CONTINUES TO INCREASE TODAY WITH MINIMUM RH VALUES
EXPECTED TO BE NEAR 35-40 PERCENT DURING THE AFTERNOON WITH
SOUTH TO SOUTHEAST WINDS OF 5-10 MPH WITH SOME ISOLATED GUSTS
TOWARD 15-20 MPH POSSIBLE. AS OUR NEXT SYSTEM APPROACHES,
MOISTURE AND RAIN CHANCES CONTINUE TO INCREASE INTO SUNDAY AND
MONDAY.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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