833
FXUS62 KCAE 090855
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
455 AM EDT FRI MAY 9 2025
SYNOPSIS
UNSETTLED WEATHER CONTINUES EACH DAY WITH SHOWER AND THUNDERSTORM
CHANCES THROUGH THE UPCOMING WEEKEND. A FEW PERIODS COULD
FEATURE SOME STRONGER SHOWERS AND THUNDERSTORMS AS WELL AS VERY
HEAVY RAINFALL.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- SHOWERS AND STORMS MOVE EAST THIS MORNING, WITH ADDITIONAL
ISOLATED ACTIVITY POSSIBLE LATER THIS AFTERNOON.
COLD FRONT MOVING THROUGH THE REGION AT THE SURFACE, WHILE
SHORTWAVE MOVES THROUGH ALOFT THIS MORNING. THIS HAS PRODUCE
WIDESPREAD SHOWERS AND THUNDERSTORMS. THIS ACTIVITY SHOULD BE
PUSHING OFF TO THE EAST THROUGH THE MORNING HOURS, WITH A PERIOD
OF DRY CONDITIONS POSSIBLE INTO THE EARLY AFTERNOON ON THE
BACKSIDE OF THE EXITING SHORTWAVE. WITH THE EXPECTED AFTERNOON
HEATING, AND LINGERING MOISTURE STILL OVER THE AREA, ISOLATED
SHOWERS AND STORMS WILL REDEVELOP ACROSS THE EASTERN FORECAST
AREA. AFTERNOON HIGHS IN THE MIDDLE 80S, WITH OVERNIGHT LOWS
FALLING INTO THE MID TO UPPER 50S TONIGHT.
SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/
KEY MESSAGE(S):
- DEVELOPING SURFACE LOW ACROSS GULF COAST BRINGS SCATTERED TO
NUMEROUS RAIN SHOWERS MAINLY TO SOUTHERN FA.
- TEMPERATURES BELOW NORMAL ARE EXPECTED WITH DEVELOPING WEDGE
CONDITIONS.
THE UPPER CUT OFF LOW CONTINUES TO REMAIN NEARLY STATIONARY
ALONG THE GULF STATES SATURDAY AS A SURFACE LOW IN THIS REGION
ALSO DEVELOPS. THIS ALL BRINGS CONTINUED MOIST SOUTHWEST FLOW
ALOFT WITH PWAT'S NEAR 1.3-1.5", HIGHEST IN THE SOUTHERN FA. AS
THE UPPER LOW SPINS OFF TO OUR WEST, SHORTWAVE ENERGY IS
EJECTED INTO THE FA AND THIS WILL BRING SCATTERED TO NUMEROUS
RAIN SHOWERS, MAINLY IN THE SOUTHERN FA DURING THE AFTERNOON AND
EVENING WHERE LOCALLY HEAVY RAIN COULD BE POSSIBLE. HIGH
PRESSURE ALSO BEGINS TO SLIDE IN ACROSS THE OHIO VALLEY AND THIS
SHOULD HELP WITH STARTING TO DEVELOP WEDGE CONDITIONS ACROSS
THE FA. THIS LEADS TO FAIRLY HIGH UNCERTAINTY IN HIGH
TEMPERATURES SATURDAY AS A DECENT SPREAD IS SEEN AMONGST MODEL
GUIDANCE BUT IN GENERAL, THERE HAS BEEN SOMEWHAT OF A DOWNWARD
TREND AND THUS I TRENDED HIGH TEMPERATURES TOWARD THE UPPER 60S
TO LOWER 70S. RAIN CHANCES THEN CARRY INTO THE OVERNIGHT AND
INTO SUNDAY AS THE UPPER LOW AND SURFACE LOW SLOWLY SHIFT
EASTWARD.
LONG TERM /SUNDAY THROUGH THURSDAY/
KEY MESSAGE(S):
- DAILY RAIN CHANCES ARE EXPECTED TO CONTINUE INTO EARLY NEXT
WEEK WITH THE POTENTIAL FOR VERY HEAVY RAINFALL.
- BELOW NORMAL DAYTIME TEMPERATURES CONTINUE TO BE EXPECTED INTO
THE EARLY WEEK.
THE UPPER LOW AND SURFACE LOW SLOWLY WORK NORTHEASTWARD THROUGH
THE EARLY WEEK BEFORE FINALLY CLEARING THE FA INTO THURSDAY.
BEFORE THIS THOUGH, SURFACE HIGH PRESSURE SLIDES INTO THE UPPER
EAST COAST AND WEDGE-LIKE CONDITIONS ARE EXPECTED TO TAKE SHAPE
AS MOIST SOUTHWEST FLOW ALOFT (PWAT'S NEAR 150-170% OF NORMAL)
RIDES OVER NORTHEASTERLY TO EASTERLY SURFACE FLOW. THIS IS
EXPECTED TO KEEP TEMPERATURES BELOW NORMAL THROUGH TUESDAY
BEFORE GRADUALLY REACHING BACK NEAR NORMAL TUESDAY AND
WEDNESDAY. IN TERMS OF RAIN CHANCES, SCATTERED TO WIDESPREAD
RAIN AND POSSIBLE THUNDERSTORMS ARE EXPECTED THROUGH THE EARLY
WEEK, ESPECIALLY MONDAY AND TUESDAY, AS THE UPPER LOW/SURFACE
LOW COMBINATION BRING STRONG FORCING FOR MULTIPLE DAYS TO THE
FA, POSSIBLY ENHANCED BY WEDGING CONDITIONS. THIS BRINGS A
MULTI-DAY PERIOD WHERE HEAVY RAINFALL SEEMS LIKELY AS THE WPC
HAS THE WHOLE CWA IN A MARGINAL RISK FOR EXCESSIVE RAINFALL
STARTING SUNDAY AND UPGRADED TO A SLIGHT RISK FOR MONDAY. THIS
IS SHOWN WELL IN THE ECMWF EFI FOR QPF WHERE MONDAY IN
PARTICULAR SHOWS EFI VALUES BETWEEN 0.70-0.80 WITH A BROAD 0 SOT
CONTOUR BUT ALSO A 1 SOT CONTOUR OVER MOST OF THE CWA,
INDICATING THE POTENTIAL CHANCES FOR A RATHER ANOMALOUS RAIN
EVENT. THIS IS DEFINITELY WORTH KEEPING AN EYE ON AS WE CONTINUE
TO GET CLOSER AND DETAILS BECOME MORE CLEAR BUT RAIN CHANCES
SLOWLY DWINDLE INTO THE MIDWEEK.
AVIATION /08Z FRIDAY THROUGH TUESDAY/
MIXTURE OF CONDITIONS THROUGH THE MORNING AS SHOWERS AND
THUNDERSTORMS PASS THROUGH TAF LOCATIONS.
NUMEROUS SHOWERS AND THUNDERSTORMS WILL BE PASSING THROUGH TAF
LOCATIONS THROUGH 11Z, THEN ACTIVITY WILL PUSH EAST AND INTO THE
COASTAL PLAIN DURING THE MORNING AND AFTERNOON HOURS. A MIXTURE
OF MVFR/IFR CEILINGS WILL REMAIN POSSIBLE AS THE SHOWER/STORM
ACTIVITY MOVES THROUGH, THEN A RETURN TO MAINLY VFR CONDITIONS
EXPECTED AROUND 14Z AS WEAK SUBSIDENCE HELP TO LIFT AND BREAK
UP SOME OF THE CLOUDINESS. VFR THEN EXPECTED THE REMAINDER OF
THE FORECAST PERIOD AT ALL LOCATIONS. LIGHT WINDS THIS MORNING
TURNING OUT OF THE WEST, THEN MORE NORTHERLY BY THIS AFTERNOON.
EXTENDED AVIATION OUTLOOK... MULTIPLE ROUNDS OF SHOWERS AND
THUNDERSTORMS ARE POSSIBLE THROUGH THE PERIOD AS AN UPPER LEVEL
LOW APPROACHES FROM THE WEST. PERIODS OF MVFR/IFR CONDITIONS ARE
POSSIBLE AT ALL TERMINALS.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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