691
FXUS62 KCAE 311617
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1217 PM EDT MON MAR 31 2025
SYNOPSIS
A LINE OF THUNDERSTORMS WILL MOVE ACROSS THE SOUTHEAST TODAY
WITH SEVERE STORMS POSSIBLE THIS AFTERNOON. WELL ABOVE NORMAL
TEMPERATURES EXPECTED FOR LATE WEEK WITH POSSIBLE RECORD HIGHS
LATE WEEK AND NEXT WEEKEND.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- SEVERE THUNDERSTORM WATCH IN EFFECT FOR THE CSRA AND PORTIONS
OF CENTRAL SC. DAMAGING WINDS ARE THE PRIMARY THREAT BUT A FEW
STORMS MAY PRODUCE A TORNADO AND LARGE HAIL.
UPDATE: SKIES CLEARING OVER THE CSRA AND MIDLANDS. THIS WILL
ALLOW THE AIR MASS TO DESTABILIZE AHEAD OF A LINE OF
THUNDERSTORMS WHICH WILL MOVE INTO THE FORECAST AREA THIS
AFTERNOON. THE LARGEST THREAT STILL APPEARS TO BE AREAS OF
DAMAGING WINDS ALONG THE LINE OF THUNDERSTORMS. THAT SAID,
CONDITIONS REMAIN SUFFICIENT TO HAVE A FEW STRONGER STORMS
EMBEDDED WITHIN THE LINE WHICH POTENTIALLY PRODUCE A TORNADO OR
LARGE HAIL.
PREVIOUS DISCUSSION: AN UPPER LEVEL TROUGH CONTINUES TO SHIFT
EASTWARD ACROSS THE MIDDLE OF THE COUNTRY WHICH WILL PUSH A COLD
FRONT THROUGH THE AREA BY TONIGHT. AHEAD OF THE FRONT TODAY,
CONTINUED SOUTHERLY LOW LEVEL FLOW AROUND THE WESTERN ATLANTIC
SURFACE HIGH WILL PROVIDE CONTINUED WARM AND MOIST ADVECTION
OVER THE FORECAST AREA LEADING TO AIR MASS DESTABILIZATION
THROUGH THE DAY. MORNING STRATUS MAY DELAY OR IMPACT THE INITIAL
DESTABILIZATION BUT GUIDANCE SUGGESTS MLCAPE VALUES WILL EXCEED
1000 J/KG DURING PEAK HEATING WITH MODEST BUT SUFFICIENT
EFFECTIVE WIND SHEAR AROUND 30-40 KNOTS WHICH SHOULD SUPPORT THE
THREAT OF SEVERE WEATHER.
LATEST HRRR RUNS CONSISTENTLY SHOWING THIS INITIAL CONVECTIVE
LINE DIMINISHING AS IT MOVES EAST OF THE MOUNTAINS BUT LEAVING A
RESIDUAL OUTFLOW BOUNDARY SOMEWHERE ACROSS THE NORTHERN
MIDLANDS. THIS COULD BECOME A FOCUS FOR ENHANCED HELICITY AND A
INCREASED TORNADO THREAT WHEN AFTERNOON CONVECTION MOVES INTO
THE REGION.
HI-RES GUIDANCE IS IN REASONABLE AGREEMENT DEVELOPING
CONVECTION ACROSS THE GULF COAST STATES AFTER 12Z WHICH THEN
TRACKS EASTWARD THROUGH THE DAY ENCOUNTERING AN INCREASINGLY
UNSTABLE HIGH THETA-E ENVIRONMENT RESULTING IN A LINE OF STRONG
CONVECTION MOVING THROUGH OUR AREA MID TO LATE AFTERNOON
(18Z-01Z) WITH POSSIBLE ISOLATED DISCRETE CELLS DEVELOPING AHEAD
OF THE LINE. HI-RES GUIDANCE ALSO SHOWING SOME UPDRAFT HELICITY
TRACKS MOVING ACROSS THE MIDLANDS AND CSRA WITH A MORE RECENT
ENHANCEMENT OF THEM ACROSS THE NORTHERN MIDLANDS (LIKELY
ASSOCIATED WITH THE FORECAST OUTFLOW BOUNDARY) WHICH IS A CHANGE
FROM PREVIOUS FORECAST THINKING THAT THE TORNADO THREAT WOULD
PRIMARILY BE CONFINED TO THE CSRA AND SOUTHEAST MIDLANDS. SO
WHILE THERE DOES NOT APPEAR TO BE A SIGNIFICANT TORNADO THREAT,
WITH A MORE LIKELY STORM MODE BEING COLD POOL DOMINATED LINEAR
MULTICELLULAR SEGMENTS, THE TORNADO THREAT DOES EXIST ACROSS THE
ENTIRE FORECAST AREA. AS MENTIONED, DAMAGING WIND GUSTS ARE THE
PRIMARY THREAT OF SEVERE WEATHER GIVEN THE FAIRLY
UNIDIRECTIONAL WIND PROFILE BUT LARGE HAIL CANNOT BE RULED OUT
EITHER. PWAT VALUES CONTINUE TO BE HIGH (OVER 200% OF NORMAL)
AND WILL SUPPORT HEAVY RAIN POTENTIAL BUT STORM MOTION SHOULD BE
HIGH ENOUGH TO LIMIT FLASH FLOOD THREAT.
TEMPERATURES TODAY SHOULD WARM AGAIN WELL INTO THE 70S WITH
SOME LOWER 80S POSSIBLE IN THE EASTERN MIDLANDS, DEPENDING ON
HOW QUICKLY THE LOWER STRATUS CAN BURN OFF. AFTER THE CONVECTION
PUSHES EAST OF THE FORECAST AREA THIS EVENING LINGERING CLOUD
COVER WILL LIMIT RADIATIONAL COOLING AND EXPECT SOME RETURN OF
STRATUS DUE TO ABUNDANT LOW LEVEL MOISTURE IN PLACE UNTIL THE
COLD FRONT PUSHES THROUGH. COLD ADVECTION SHOULD COMMENCE BEHIND
THE FRONT LATE TONIGHT AND OVERNIGHT LOWS EXPECTED TO FALL INTO
THE 50S RANGING FROM THE LOWER 50S WEST TO UPPER 50S EAST.
SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/
- A TRANSIENT COOL, DRY AIRMASS WILL ON TUESDAY WILL MAKE WAY
FOR A STEADY WARM UP AND MOISTURE RETURN THAT STARTS
WEDNESDAY.
FOLLOW MONDAY'S COLD FRONT PASSAGE, TUESDAY WILL BE THE COOLEST DAY
FOR THE FORECAST PERIOD AS TEMPS REMAIN IN THE 70'S. WITH BROAD
COLD, DRY ADVECTION AND DOWNSLOPING, PWAT'S WILL DROP DOWN BELOW
0.5" AND SURFACE DEW POINTS WILL FALL INTO THE 40'S. AS BROAD
OFFSHORE HIGH PRESSURE AND RIDGING DEVELOPS INTO WEDNESDAY, WARMING
TEMPS AND MOISTURE WILL RETURN. SOME UPSLOPE AND ISENTROPICALLY
FORCED SHOWERS ARE POSSIBLE AS WE FLIP OVER TO A WARM ADVECTION
REGIME THANKS TO THAT STRONG BERMUDA HIGH. SO A FEW SHOWERS ARE
EXPECTED MAINLY IN THE UPSTATE AND WESTERN MIDLANDS WEDNESDAY.
OTHERWISE, TEMPS WILL PUSH INTO THE MID 80'S IN MOST SPOTS, 10-15
DEGREES ABOVE AVERAGE.
LONG TERM /THURSDAY THROUGH SUNDAY/
- HIGHLY ANOMALOUS WARMTH EXPECTED WITH NEAR RECORD HIGH TEMPS
THURSDAY THROUGH SUNDAY.
THE LONG TERM PERIOD WILL BE DOMINATED BY DEEP MID-UPPER LEVEL
RIDGING AND AN EXTREMELY STRONG OFFSHORE SURFACE HIGH. THESE WILL
YIELD NEAR OR EXCEEDING RECORD HIGH TEMPS ACROSS MUCH OF THE AREA
STARTING THURSDAY AND LASTING THROUGH SUNDAY; THE TIMING OF WHEN THE
NEXT FRONT ACTUALLY CLEARS THE AREA NEXT WEEK IS STILL UNCERTAIN.
REGARDLESS, HIGH TEMPS WELL INTO THE 80'S OR LOW 90'S ARE EXPECTED
DURING THIS WINDOW, WITH A REMARKABLE SIGNAL IN THE EC EFI AND NAEFS
FOR ANOMALOUS MAX AND MIN TEMPS. EC EFI SHOWS CONSISTENT 0.9+ WITH
SOT OF OVER 1.0 FOR BOTH MAX AND MIN TEMPS FRIDAY AND SATURDAY.
NAEFS SHOWS NEAR RECORD 500MB HEIGHTS OFF THE ATLANTIC COAST WITH
99TH PERCENTILE HEIGHTS AND TEMPS THROUGHOUT FRIDAY AND SATURDAY. SO
OVERALL, GUIDANCE IS FLAGGING THIS PERIOD AS ONE OF THE MORE
ANOMALOUS TEMP PATTERNS WE HAVE SEEN IN AWHILE. EXACTLY WHEN THIS
RIDGING WILL CLEAR OUT IS A BIT UNCERTAIN, BUT GEFS AND ECE BOTH
PUSH A STRONG FRONT THROUGH THE REGION SOMETIME SUNDAY OR MONDAY OF
NEXT WEEK, FOLLOWING BY A NOTABLE COOL-DOWN INTO THE EXTENDED RANGE.
AVIATION /16Z MONDAY THROUGH FRIDAY/
STRATUS HAS LIFTED WITH MVFR CEILINGS BEING SEEN AT ALL SITES
AS ISOLATED SHOWERS AND POSSIBLE STORMS ARE DEVELOPING IN
CENTRAL TO EASTERN GA AHEAD OF THE MAIN LINE THAT IS ENTERING
WESTERN GA AT THIS TIME.
ANY LINGERING STRATUS HAS MIXED OUT WITH SOUTHWEST WINDS AROUND
5-10 KTS BUT WE KEEP MVFR CEILINGS AS MOISTURE BEGINS TO SURGE
INTO THE REGION, LIMITING THE BREAKING UP CLOUDS, THOUGH SOME
SMALL BREAKS ARE NOW BEING SEEN NEAR AGS/DNL. THE MAIN LINE OF
STRONG TO SEVERE THUNDERSTORMS IS NOW ENTERING WESTERN GA BUT
AHEAD OF THIS, ISOLATED SHOWERS ARE FORMING INTO CENTRAL AND
EASTERN GA. SOME OF THESE WILL HAVE THE POSSIBILITY OF
DEVELOPING INTO THUNDERSTORMS AS INSTABILITY CONTINUES TO
INCREASE AND THUS A COUPLE OF THESE COULD BE NEARING AGS/DNL IN
THE NEXT HOUR OR SO, BEFORE CONTINUING WEST, ENTERING NEAR
CUB/CAE BY 18-19Z. MOST OF THIS ACTIVITY IS REMAINING NORTH OF
OGB AT THIS TIME. THE TIMING FOR THE MAIN LINE OF STORMS IS
CURRENTLY LOOKING TO ENTER AGS/DNL BY 18-20Z, CUB/CAE BY
19-21Z, AND OGB BY 20-23Z. THIS IS EXPECTED TO BRING STRONG
WINDS WITH GUSTS OVER 35 KTS POSSIBLE AND POSSIBLE CEILING AND
VISIBILITY RESTRICTIONS FOR A COUPLE HOURS AS THE MAIN LINE
PASSES. BEHIND THE LINE, SOME ISOLATED SHOWERS MAY LINGER INTO
THE EVENING BUT THE MAIN IMPACT BEHIND THIS LINE OF STORMS
CONTINUES TO BE ANOTHER STRATUS DECK THAT LOOKS TO BUILD BACK IN
AFTER 6-8Z WITH LIGHT AND VARIABLE WINDS.
EXTENDED AVIATION OUTLOOK...THE COLD FRONT IS EXPECTED TO MOVE
THROUGH THE AREA TONIGHT WITH LINGERING POSSIBLE RESTRICTIONS
INTO EARLY TUESDAY. EARLY MORNING LOW CLOUDS CONTINUE TO BE
POSSIBLE WEDNESDAY AND THURSDAY MORNING.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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