946
FXUS62 KCHS 071832
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
232 PM EDT WED MAY 7 2025
SYNOPSIS
A FRONT WILL REMAIN STALLED NEARBY THROUGH THE WEEKEND AS
CUT-OFF LOW CONTINUES TO MOVE CLOSER TO THE REGION. THIS WILL
ALLOW AN UNSETTLED, WET PATTERN TO PERSIST OVER THE NEXT
SEVERAL DAYS.
NEAR TERM /THROUGH TONIGHT/
THIS AFTERNOON: ALOFT, H5 SHORTWAVE ENERGY WILL ROUND THE NORTHERN
PERIPHERY OF A RIDGE EXTENDING ACROSS THE NORTHEAST GULF TO THE
WESTERN ATLANTIC. AT THE SFC, THE SETUP IS QUITE NEBULOUS WITH A
SUBTLE BOUNDARY SITUATED ACROSS SOUTHERN GEORGIA AND WESTWARD ALONG
THE NORTHERN GULF COAST. OVERALL, FORCING IS NOT ALL THAT IMPRESSIVE
LOCALLY, BUT REMNANT OUTFLOW FROM THE PREVIOUS DAY HAS BEEN A
SUFFICIENT SOURCE OF LIFT TO PRODUCE LIGHT SHOWERS ACROSS INLAND
ZONES. CLOSER TO THE COAST, HI-RES GUIDANCE REMAINS IN GENERAL
AGREEMENT OF SHOWERS AND THUNDERSTORMS OCCURRING ALONG THE IMMEDIATE
GEORGIA COAST AND PERHAPS AS FAR NORTH INTO BEAUFORT COUNTY, SC
DURING THE NEXT HOUR, WHERE SBCAPE AROUND 2000 J/KG AND EFFECTIVE 0-
6KM BULK SHEAR AROUND 30 KT SUGGESTS THE POTENTIAL FOR A STRONGER
THUNDERSTORM. HOWEVER, THE WINDOW OF OPPORTUNITY IS ENDING SHORTLY
WITH ONGOING CONVECTION DRIFTING OFFSHORE, AND LIKELY REMAINING
ACROSS COASTAL WATERS FOR THE REST OF THE DAY. HIGH TEMPS WILL
RANGE IN THE UPPER 70S/LOWER 80S, THOUGH DISRUPTION TO THE TYPICAL
DIURNAL TREND IS EXPECTED ALONG AND SOUTH OF I-16 AS SHOWERS/THUNDERSTORMS
OCCUR.
TONIGHT: AFTERNOON SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
PUSH OFFSHORE BY THE EARLY EVENING AND FROM THEN ON THERE ISN'T
A TON OF CONFIDENCE IN HOW SHOWER POTENTIAL WILL WORK OUT
OVERNIGHT. WE WILL REMAIN LARGELY DEVOID OF ANY LARGE SCALE
FORCING, THOUGH THERE ARE SOME SUGGESTIONS THAT SUBTLE SHORTWAVE
ENERGY WILL PASS THROUGH WITHIN THE WESTERLY FLOW. THE ILL-
DEFINED SURFACE BOUNDARY IS EXPECTED TO BE ALIGNED SOUTH OF THE
AREA NEAR THE FL STATE LINE. SO, THE FORECAST ALLOWS FOR RAIN
CHANCES TO END IN THE EVENING BUT WE DO ALLOW 20 PERCENT CHANCES
TO COME BACK IN LATE TO ACCOUNT FOR POSSIBLE ISOLATED SHOWER
DEVELOPMENT WITHIN THE WARM AND MOIST ENVIRONMENT. LOWS ARE
FORECAST TO BE IN THE UPPER 50S TO LOW 60S INLAND, AND THE MID
60S ALONG THE COAST.
SHORT TERM /THURSDAY THROUGH SATURDAY/
THURSDAY: AS AN UPPER-LVL LOW SITUATED OVER THE MID-MISSISSIPPI
VALLEY APPROACHES THE REGION, THE ALMOST STATIONARY FRONT WILL
CONTINUE TO LINGER NEARBY. COMPARED TO THE PAST WEEK OF
GUIDANCE, THIS PATTERN HAS BEEN MORE SLOW TO PROGRESS AND MAY
SUPPORT ADDITIONAL RAINFALL IF THIS TREND CONTINUES OVER THE
NEXT COUPLE DAYS. WHILE GFS/CMC POINT TO A RATHER DRY FORECAST
TODAY, ALL OTHER GUIDANCE SUGGESTS OTHERWISE. EXPECT SHOWERS AND
THUNDERSTORMS TO DEVELOP IN THE MORNING (~12-13Z) ACROSS
SOUTHEAST GEORGIA AND EVENTUALLY INTO SOUTHEAST SOUTH CAROLINA
IN THE EARLY AFTERNOON (~18- 19Z). LOCATED ON THE COOLER SIDE OF
THE UPPER-LVL LOW, INSTABILITY REMAINS QUITE LIMITED THROUGHOUT
THE DAY WITH SBCAPE VALUES MOSTLY WAVERING ~1000 J/KG. HOWEVER
HEADING INTO THE AFTERNOON, SRH VALUES BECOME MORE IMPRESSIVE
AND THE POTENTIAL TO SEE SOME ORGANIZED THUNDERSTORMS IS NOT
TOTALLY OFF THE TABLE. WITH A FRONTAL BOUNDARY PUSHING OFFSHORE
IN THE EVENING, MOST OF THE SHOWERS AND THUNDERSTORMS WILL SHIFT
OVER THE WATERS. ADDITIONALLY, WPC HAS HIGHLIGHTED SOUTHEAST
GEORGIA IN A MARGINAL RISK AS THIS AREA WILL MOST LIKELY SEE THE
MOST RAINFALL (~0.25-0.50"). SOUTHEASTERLY WINDS COULD BECOME
QUITE GUSTY ALONG THE COASTLINE IN THE EVENING WITH THE
SEABREEZE AND THE FRONT SHIFTING OFFSHORE. DESPITE THE LACK OF
SUN, HIGHS WILL CLIMB INTO THE LOW TO MID 80S AND OVERNIGHT LOWS
WILL DROP INTO THE LOW TO MID 60S INLAND AND UPPER 60S CLOSER
TO THE COASTLINE.
FRIDAY: AS THIS UPPER-LVL LOW SITUATES ITSELF IN THE DEEP
SOUTH, AN ASSOCIATED COLD FRONT WILL PASS THROUGH THE REGION
THROUGHOUT THE DAY. A GOOD AMOUNT OF GUIDANCE INDICATES THAT
THIS LOW WILL YIELD NUMEROUS SHOWERS AND THUNDERSTORMS
THROUGHOUT THE DAY. ADDITIONALLY, WPC HAS HIGHLIGHTED THE ENTIRE
REGION UNDER A MARGINAL RISK FOR EXCESSIVE RAINFALL. WITH PWAT
VALUES RANGING ~1.50-2.00 INCHES AND EXTREMELY MOIST
SOUTHWESTERLY FLOW BEING ADVECTED INTO THE REGION, DECENT
AMOUNTS OF RAINFALL COULD BE SEEN. RAINFALL AMOUNTS FOR FRIDAY
RANGE FROM 0.75 TO 1.25 INCHES, WITH MOST PRECIPITATION FALLING
IN SOUTHEAST GEORGIA AGAIN. EXPECT TEMPERATURES TO BE NEAR
NORMAL ON FRIDAY.
SATURDAY: THIS UPPER-LVL LOW WILL ALMOST PARK ITSELF ACROSS THE
GULF STATES AND CONTINUE TO PUSH RICH MOISTURE INTO THE
SOUTHEAST. EXPECT SHOWERS AND THUNDERSTORMS TO CONTINUE
THROUGHOUT THE DAY. WPC HIGHLIGHTED THE ENTIRE REGION UNDER A
MARGINAL RISK FOR EXCESSIVE RAINFALL AGAIN. THIS APPEARS TO THE
HEAVIEST DAY OF RAINFALL WITH PRECIPITATION AMOUNTS RANGING FROM
1.0 TO 1.50 INCHES. DUE TO THE RELATIVELY DRY ANTECEDENT
CONDITIONS, THE OVERALL FLASH FLOODING POTENTIAL REMAINS ON THE
LOWER SIDE. GIVEN THE OVERALL PATTERN, TEMPERATURES WILL BE
BELOW NORMAL FOR THIS TIME OF YEAR WITH HIGHS ONLY REACHING INTO
THE LOW TO MID 70S WITH POCKETS OF UPPER 70S IN SOUTHEAST
GEORGIA. NORTHEASTERLY WINDS WILL LIKELY BECOME GUSTY AGAIN IN
THE EVENING (MAINLY ALONG THE COASTLINE) AS THE AFOREMENTIONED
FRONTAL BOUNDARY LINGERS NEARBY.
LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/
AS THIS CUT-OFF LOW CONTINUES TO SIT ACROSS THE DEEP SOUTH AND
A FRONTAL BOUNDARY LINGERS NEARBY, EXPECT AN EXTENDED PERIOD OF
UNSETTLED, WET WEATHER. WITH DEEP TROPICAL MOISTURE POOLING IN
FROM THE GULF, THIS PATTERN WILL SUPPORT DAILY HEAVY RAINFALL
THREATS INTO EARLY NEXT WEEK. THERE IS POTENTIAL TO SEE RAINFALL
AMOUNTS OF 2+ INCHES IN SOME SPOTS. EVENTUALLY THIS CLOSED LOW
WILL BEGIN TO SLOWLY SHIFT NORTHEASTWARD AND PLACE THE REGION IN
FAVORABLE LOCATION FOR STRONG UPPER-LVL DIVERGENCE. MULTIPLE
ROUNDS OF POTENTIALLY HEAVY SHOWERS AND THUNDERSTORMS WILL PASS
THROUGH THIS PERIOD AND ALLOW FOR SOME VERY NEEDED RAINFALL.
THIS SETUP WILL INDUCE NEAR AND BELOW NORMAL TEMPERATURES.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
CHS/JZI: THERE REMAINS POTENTIAL FOR LIGHT SHOWERS TO DEVELOP/MOVE
ACROSS THE TERMINALS THIS AFTERNOON, BUT CONDITIONS SHOULD GENERALLY
REMAIN VFR THROUGH THE DAY. TONIGHT, SFC WINDS WILL BECOME LIGHT AND
GUIDANCE SUGGESTS MVFR CIGS DEVELOPING ACROSS BOTH TERMINALS BETWEEN
08Z-14Z THURSDAY. CHANCES OF SHOWERS AND/OR THUNDERSTORMS INCREASE
BY LATE THURSDAY MORNING, BUT PROBABILITIES ARE TOO LOW TO INCLUDE
PRIOR TO 18Z THURSDAY.
SAV: A FEW THUNDERSTORMS COULD IMPACT THE TERMINAL DURING THE NEXT
FEW HOURS AS ACTIVITY CONTINUES ALONG THE GEORGIA COAST. TEMPO MVFR
CONDITIONS ARE POSSIBLE BETWEEN 18-20Z FOR THIS ACTIVITY. VFR
CONDITIONS PREVAIL LATE AFTERNOON THROUGH EVENING HOURS, BUT
GUIDANCE SUGGESTS PREVAILING MVFR AND POSSIBLY IFR CONDITIONS
OCCURRING BETWEEN 08Z-14Z THURSDAY. CHANCES OF SHOWERS AND/OR
THUNDERSTORMS INCREASE LATE THURSDAY MORNING, BUT CONFIDENCE IN
ARRIVAL PRIOR TO 18Z IS TOO LOW TO INCLUDE IN THE LATEST TAF ISSUANCE.
EXTENDED AVIATION OUTLOOK: EXPECT MULTIPLE ROUNDS OF SCATTERED
SHOWERS AND THUNDERSTORMS ASSOCIATED WITH A NEARBY FRONT TO
DEVELOP THROUGH THE PERIOD. PERIODS OF MVFR/IFR CONDITIONS ARE
POSSIBLE AT CHS/JZI/SAV EACH DAY.
MARINE
THIS AFTERNOON THROUGH TONIGHT: A WEAK PRESSURE GRADIENT PLACED
ACROSS COASTAL WATERS WILL KEEP WINDS AND SEAS WILL BELOW SMALL
CRAFT ADVISORY THRESHOLDS. WINDS WILL GENERALLY BECOME MORE DIRECTLY
ONSHORE MID-LATE AFTERNOON (EAST/SOUTHEAST), BUT REMAIN AROUND 10 KT
OR LESS. THE EXCEPTION IS ACROSS THE CHARLESTON HARBOR, WHERE A
NORTHWEST WIND HOLDS INITIALLY, THEN TURNS MORE SOUTHEAST LATE DAY.
OVERNIGHT, LIGHT SOUTHERLY FLOW SHOULD CONTINUE WITH WIND SPEEDS NO
MORE THAN 5-10 KT. SEAS WILL AVERAGE AROUND 2 FT THROUGH THE PERIOD.
ALTHOUGH 3 FT SEAS ARE POSSIBLE WELL OFFSHORE ACROSS OUTER GEORGIA
WATERS.
FRIDAY THROUGH MONDAY: AS THIS UPPER-LVL LOW APPROACHES THE
REGION OVER THE NEXT COUPLE DAYS, A NEARBY STATIONARY FRONT AT
THE SURFACE WILL FLUCTUATE BACK AND FORTH OVER THE ATLANTIC
WATERS. THIS WILL SUPPORT UNSETTLED WEATHER CONDITIONS AND
SHOWERS AND THUNDERSTORMS COULD POSSIBLE EACH DAY. HOWEVER,
CONDITIONS SHOULD REMAIN UNDER SMALL CRAFT ADVISORY CRITERIA. IN
GENERAL, OFFSHORE WINDS WILL PEAK ~10 TO 15 KT WITH GUSTS (~20
KT) BECOMING SLIGHTLY STRONGER WITH THE SEA BREEZE EACH EVENING.
THANKS TO WINDS IN THE TROPICAL EASTERLIES, EASTERLY SWELL
SHOULD BE ON TAP AND ALLOW FOR SOME GOOD SURF TO DEVELOP. SEAS
WILL BE FROM 2 TO 4 FT OVER THE WEEKEND AND THEN BECOMING 4 TO 5 FT
ON MONDAY.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...DPB
SHORT TERM...DENNIS
LONG TERM...DENNIS
AVIATION...BSH/DENNIS
MARINE...DENNIS/DPB
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