275
FXUS62 KCAE 012356
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
756 PM EDT TUE JUL 1 2025
SYNOPSIS
A WEAK FRONT APPROACHES THE REGION LEADING TO INCREASING RAIN
AND THUNDERSTORM CHANCES THROUGH WEDNESDAY. RAINFALL MAY BE
HEAVY AT TIMES AND COULD LEAD TO LOCALIZED FLOODING MAINLY IN
FLOOD PRONE AREAS. DRIER AIR WORKS INTO THE FORECAST AREA FROM
THE NORTH AND WEST FOR THE LATTER PORTION OF THE WEEK LIMITING
THUNDERSTORM COVERAGE WITH HIGHEST CHANCES TOWARDS THE COAST.
ISOLATED TO SCATTERED SHOWERS POSSIBLE THIS WEEKEND AS LOW
PRESSURE POTENTIALLY DEVELOPS ALONG THE REMNANT FRONTAL
BOUNDARY.
NEAR TERM /UNTIL 7 AM WEDNESDAY MORNING/
KEY MESSAGE(S):
- AN APPROACHING FRONT WILL BRING SHOWERS AND STORMS ACROSS THE AREA
THIS EVENING.
NOT TOO MUCH CHANGE IN THE FORECAST THINKING FOR THIS AFTERNOON AND
EVENING WITH AN APPROACHING TROUGH AND WEAK SURFACE FRONT NEARING
THE AREA. ABUNDANT LOW-DEEP LAYER MOISTURE HAS PUSHED PWAT'S BACK TO
AROUND 2.0" AND SURFACE DEW POINTS HAVE HELD STEADY IN THE LOW-MID
70'S. DESPITE THE APPROACHING FRONT, MID-LEVEL LAPSE RATES WILL
REMAIN FAIRLY MEDIOCRE AND SURFACE HEATING WILL NOT BE TERRIBLY
IMPRESSIVE EITHER, YIELDING A MODEST ML CAPE ENVIRONMENT IN THE
HREF SUITE (AROUND 1000 J/KG). AGAIN, DESPITE AN APPROACHING
TROUGH, THERE IS ONLY WEAK MID-DEEP LAYER WINDS ASSOCIATED WITH
IT AND THEREFORE ONLY MODEST SHEAR. THE HREF HAS BEEN CONSISTENT
IN PRODUCING WIDESPREAD SHOWERS AND STORMS THIS EVENING, WHICH
LINES UP NICELY WITH THIS TYPE OF MODEST FORCING, MODEST CAPE,
AND HIGH MOISTURE ENVIRONMENT. SEVERE THREAT WILL REMAIN HIGHLY
ISOLATED GIVEN THE LACK OF SHEAR AND WEAK DOWNDRAFT POTENTIAL
WITH A LACK OF DCAPE AND DRY AIR ALOFT. SOME BOUNDARY COLLISIONS
OR CELL MERGERS COULD POP A SEVERE STORM HOWEVER. HEAVY RAIN
POTENTIAL IS PRESENT WITH THESE STORMS, BUT STORM MOTION SHOULD
PRECLUDE MUCH FLASH FLOODING THREAT. BUT LIKE WITH SEVERE, THE
THREAT SHOULD BE ISOLATED BUT CANNOT RULE OUT A FEW AREAS OF
FLASH FLOODING GIVEN THE HIGH PWAT'S AND EFFICIENT INSTABILITY
PROFILES.
CONVECTION IS EXPECTED TO LINGER INTO THE EVENING HOURS PARTICULARLY
ACROSS THE WESTERN PART OF THE AREA AS THE FRONTAL BOUNDARY
APPROACHES FROM THE WEST BUT INTENSITY SHOULD WANE BY LATE EVENING.
WIDESPREAD CLOUD COVER OVERNIGHT SHOULD LIMIT RADIATIONAL COOLING
AND EXPECT LOWS TO BE IN THE LOWER 70S.
SHORT TERM /7 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/
KEY MESSAGE(S):
- WIDESPREAD SHOWERS AND STORMS
- LOCALIZED FLASH FLOOD RISK MAINLY IN FLOOD PRONE AREAS
AN UPPER TROUGH WILL SHIFT INTO THE EASTERN US ON WEDNESDAY. THE
ASSOCIATED COLD FRONT WILL SAG INTO THE SOUTHEAST PROVIDING
SURFACE CONVERGENCE TO AID IN CONVECTIVE INITIATION DURING THE
AFTERNOON. PWATS ABOVE 2 INCHES, LOW LEVEL CONVERGENCE, AND WEAK
SYNOPTIC SUPPORT WILL PROMOTE WIDESPREAD SHOWERS AND STORMS
DURING THE AFTERNOON. HEAVY RAIN WILL BE POSSIBLE GIVEN THE
ABOVE NORMAL ATMOSPHERIC MOISTURE AND WEAK TO MODERATE
INSTABILITY IN TALL, SKINNY CAPE PROFILES. ALTHOUGH WIDESPREAD
FLASH FLOODING APPEARS UNLIKELY DUE TO STORM MOTION VALUES
AROUND 10 KTS, WE MAY STILL SEE LOCALIZED FLASH FLOODING, MAINLY
IN URBAN AREAS AND OTHER FLOOD PRONE LOCATIONS. WITH WIDESPREAD
RAIN EXPECTED, TEMPERATURES SHOULD BE A BIT COOLER WEDNESDAY
WITH HIGHS IN THE MID TO UPPER 80S.
LONG TERM /THURSDAY THROUGH TUESDAY/
KEY MESSAGE(S):
- DRIER AIR ENTERS THE REGION FROM THE NORTH AND WEST
A WEAK FRONTAL BOUNDARY WILL SETTLE ACROSS THE SOUTHEAST DURING
THE LATTER PORTION OF THE WEEK. WITH DRIER AIR IMPINGING ON THE
FA BEHIND THE FRONT WE WILL SEE LOWER RAIN CHANCES FROM THURSDAY
TO SATURDAY COMPARED TO WEDNESDAY. DEPENDING ON WHERE THE FRONT
SETTLES, STORM CHANCES MAY BE LIMITED TO THE EASTERN HALF OF THE
FA WITH HIGHER RAIN CHANCES NEAR THE COAST. THIS WEEKEND SOME
ENSEMBLE MEMBERS INDICATE POTENTIAL FOR LOW PRESSURE TO DEVELOP
ALONG THE REMNANTS OF THE OLD FRONTAL BOUNDARY. IF THIS OCCURS
THAT MAY DRAW MOISTURE BACK INTO THE REGION DEPENDING ON THE
LOCATION OF DEVELOPMENT.
AVIATION /00Z WEDNESDAY THROUGH SUNDAY/
LOW END RISK FOR A PASSING SHOWER OR THUNDERSTORM THIS
EVENING....
THUNDERSTORMS HAVE STRUGGLED TO DEVELOP TODAY ACROSS THE
FORECAST AREA. ONE LINE OF DECAYING CONVECTION IS APPROACHING
AGS/DNL WITH A SECOND CLUSTER APPROACHING OGB. HAVE ADDED A
TEMPO FOR THUNDERSTORMS DURING THE NEXT FEW HOURS AT THESE SITES
WHILE KEEPING VCSH AT CAE/CUB ON THE OFF CHANCE SOMETHING
DEVELOPS THERE BEFORE NIGHTFALL. MUCH OF THE OVERNIGHT PERIOD
IS EXPECTED TO BE QUIET AS ANY LINGERING CONVECTION QUICKLY
DIMINISHES WITH THE LOSS OF DAYTIME HEATING. GUIDANCE IS ONCE
AGAIN HINTING AT THE POTENTIAL FOR LOW CEILINGS TOMORROW MORNING
SO OPTED FOR MAINLY A PERSISTENCE FORECAST AT ALL TERMINALS
WITH A TEMPO FOR LIFR AT DNL WHERE DECKS WERE THE LOWEST THIS
MORNING. CEILINGS SHOULD IMPROVE AROUND MIDDAY GIVING WAY TO
SCATTERED CUMULUS AND EVENTUALLY THE THREAT FOR SHOWERS AND
THUNDERSTORMS IN THE AFTERNOON. LEAVING THUNDER CHANCES OUT OF
THE TAFS FOR NOW DUE TO LOWER CONFIDENCE. PROBABILITIES FOR
THUNDER IN THE AFTERNOON WILL LIKELY BE HIGHEST AT OGB.
EXTENDED AVIATION OUTLOOK... PATCHY LOW CLOUDS AND/OR GROUND
FOG POSSIBLE EACH NIGHT ALONG WITH DIURNALLY FAVORED SHOWERS AND
THUNDERSTORMS.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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