089
FXUS62 KCHS 050622
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
222 AM EDT WED AUG 5 2026
WHAT HAS CHANGED
ALL KEY MESSAGES AND SECTIONS WERE UPDATED.
KEY MESSAGES
- 1) SHOWERS AND THUNDERSTORMS WILL IMPACT PARTS OF THE
CHARLESTON TRI-COUNTY THIS MORNING BRINGING A RISK FOR HEAVY
RAINFALL AND LOCALIZED FLOODING THROUGH MID-MORNING.
- 2) ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL IMPACT THE
REGION THIS AFTERNOON AHEAD OF THE AFTERNOON SEA BREEZE.
- 3) A TYPICAL SUMMERTIME PATTERN WILL REMAIN IN PLACE THROUGH
THE UPCOMING WEEKEND. ISOLATED STRONG TO SEVERE THUNDERSTORMS
AND THE THREAT FOR LOCALIZED HEAVY RAINFALL WILL BE POSSIBLE
EACH DAY.
DISCUSSION
KEY MESSAGE 1: SHOWERS AND THUNDERSTORMS WILL IMPACT PARTS OF
THE CHARLESTON TRI-COUNTY THIS MORNING BRINGING A RISK FOR
HEAVY RAINFALL AND LOCALIZED FLOODING THROUGH MID-MORNING.
A COMBINATION OF MODEST TO STRONG SURFACE MOISTURE CONVERGENCE
ACROSS THE ATLANTIC IS PROMOTING THE DEVELOPMENT OF
SHOWERS/TSTMS OFFSHORE EARLY THIS MORNING. AS THE MEAN STEERING
FLOW STEADILY BACKS FROM THE SOUTHWEST TO SOUTH THE RISK FOR
CONVECTION MOVING INLAND FROM OFF THE ATLANTIC WILL INCREASE
ACROSS PARTS OF THE LOWER SOUTH CAROLINA COAST THROUGH DAYBREAK
WITH THE GREATEST COVERAGE EXPECTED TO OCCUR ACROSS THE EASTERN
PORTIONS OF THE CHARLESTON TRI-COUNTY REGION, INCLUDING DOWNTOWN
CHARLESTON. SATELLITE DERIVED PWAT DATA FROM GOES-E SHOW A
LARGE PLUME OF PWATS >2.25" LURKING JUST OFFSHORE WHICH MATCHES
OUTPUT FROM THE LATEST RAP. THE RAP SHOWS THIS AREA OF PWATS
2.25-2.50" ADVECTING QUICKLY ONSHORE ACROSS THE CHARLESTON TRI-
COUNTY OVER THE NEXT FEW HOURS AS BANDS OF SHOWERS/TSTMS PROPAGATE
INLAND. INTENSE HOURLY RAINFALL RATES WILL LIKELY OCCUR WITHIN
POCKETS OF DEEPER CONVECTION AS PWATS SURGE, ESPECIALLY WHERE A
RIBBON OF MLCAPE 1500-2000 J/KG IS FORECAST TO NUDGE INLAND
FROM OFF THE ATLANTIC. THIS WILL BEING A RISK FOR HEAVY RAINFALL
AND POSSIBLY SOME LOCALIZED FLOODING ACROSS PARTS OF CHARLESTON,
BERKELEY, DORCHESTER AND COLLETON COUNTIES, ESPECIALLY IN THE
URBAN AREAS ACROSS THE CHARLESTON METRO AREA AS WELL AS LOW-
LYING AND POOR DRAINAGE AREAS IN THE MORE RURAL LOCATIONS.
DOWNTOWN CHARLESTON WILL NEED TO BE WATCHED CAREFULLY AS A QUICK
1-2" IN AN HOUR COULD EASILY YIELD SIGNIFICANT ISSUES SHOULD
CONVECTION BEGIN TO ALIGN ACROSS THE PENINSULA. THE 05/00Z HREF
NEIGHBORHOOD PROBABILITIES FOR >1"/3HRS ARE RUNNING ABOUT 40-70%
AND 10-20% FOR >3"/3HRS, HIGHEST ROUGHLY ALONG AND EAST OF AN
EDISTO ISLAND-NORTH CHARLESTON-JAMESTOWN LINE.
KEY MESSAGE 2: ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS WILL
IMPACT THE REGION THIS AFTERNOON AHEAD OF THE AFTERNOON SEA
BREEZE.
THIS AFTERNOON AND TONIGHT: THE RISK FOR ISOLATED TO SCATTERED
SHOWERS/TSTMS WILL REFOCUS INLAND THIS AFTERNOON/EVENING AS A
MODEST SEA BREEZE MOVES INLAND. THE UPPER LOW TO THE WEST WILL
BEGIN TO WEAKEN TODAY AND IS FORECAST TO GRADUALLY OPEN UP INTO
A WAVE BY TONIGHT AS A STRONG SHORTWAVE PIVOTS INTO THE MID-
MISSISSIPPI VALLEY. SIMILAR TO YESTERDAY, THERE ARE NO
DISCERNIBLE SPOKES OF VORTICITY THAT ARE PROGGED TO CROSS THE
AREA DURING THE DIURNAL MAXIM. THERE IS NO MEANINGFUL FORCING IS
NOTED IN MODEL CROSS SECTIONS AS A RESULT. CONVECTION WILL
THEREFORE ONCE AGAIN BE AIRMASS DRIVEN AND ITS EVOLUTION WILL
BE MAINLY DRIVEN BY MESOSCALE PROCESSES. AN ISOLATED STRONG TO
SEVERE TSTM COULD OCCUR JUST ABOUT ANYWHERE ALONG/WEST OF THE
SEA BREEZE. ACTIVITY WILL QUICKLY WANE THIS EVENING, BUT THERE
ARE INCREASING SIGNALS THAT ANOTHER ROUND OF NOCTURAL CONVECTION
COULD DEVELOP OVER THE ATLANTIC OVERNIGHT AS LOW-LEVEL
CONVERGENCE REFOCUSES CLOSER TO THE WEST WALL OF THE GULF
STREAM. THE 850-250 HPA STEERING FLOW LOOKS TO REMAIN SOUTH TO
SOUTH/SOUTHEAST THROUGH THE NIGHT, SO THIS ACTIVITY WILL LIKELY
PUSH ONSHORE EARLY THURSDAY MORNING AND IMPACT AREAS ROUGHLY
ALONG/EAST OF THE I-95 CORRIDOR.
KEY MESSAGE 3: A TYPICAL SUMMERTIME PATTERN WILL REMAIN IN
PLACE THROUGH THE UPCOMING WEEKEND. ISOLATED STRONG TO SEVERE
THUNDERSTORMS AND THE THREAT FOR LOCALIZED HEAVY RAINFALL WILL
BE POSSIBLE EACH DAY.
THURSDAY THROUGH THE WEEKEND: THE PATTERN ALOFT WILL BE
DOMINATED BY DEEP HIGH PRESSURE OVER THE WESTERN ATLANTIC AND
THE WESTERN CONUS. THIS WILL SUPPORT DAILY SCATTERED CONVECTION
THROUGH THE WEEKEND, WITH THE SEA BREEZE AND ANY REMNANT OUTFLOW
BOUNDARIES SERVING AS THE PRIMARY FOCUS FOR AFTERNOON AND
EVENING THUNDERSTORM DEVELOPMENT. PERSISTENT SOUTHERLY FLOW WILL
CONTINUE TO ADVECT DEEP MOISTURE INTO THE REGION. MODERATE
INSTABILITY LOOKS TO DEVELOP EACH AFTERNOON, WITH SBCAPE VALUES
RISING TO 2500-3000 J/KG. PWAT VALUES NEAR 2 INCHES NEARLY EACH
DAY WILL SUPPORT EFFICIENT RAINFALL RATES, WITH SOME STORMS
CAPABLE OF DROPPING A QUICK 1-2 INCHES OF RAIN IN A SHORT
PERIOD. IN ADDITION, SLOW STORM MOTIONS OF AROUND 10 KT,
COMBINED WITH TRAINING OR REPEATED ROUNDS OF CONVECTION, COULD
INCREASE THE POTENTIAL FOR ISOLATED INSTANCES OF MINOR FLOODING,
ESPECIALLY IN LOW-LYING AND POOR DRAINAGE AREAS. FRIDAY COULD
BE THE EXCEPTION, AS SOMEWHAT DRIER AIR WITH POCKETS OF PWATS
AROUND 1.5 TO 1.7 INCHES SHOULD LIMIT THE FLOODING THREAT.
LASTLY, WITH LITTLE SHEAR IN THE ENVIRONMENT, STORMS WILL REMAIN
PULSE-LIKE. ALTHOUGH WIDESPREAD SEVERE WEATHER IS NOT EXPECTED,
A FEW STRONGER STORMS COULD PRODUCE DAMAGING WIND GUSTS.
AVIATION /06Z WEDNESDAY THROUGH SUNDAY/
05/06Z TAFS:
KCHS/KJZI: EARLY MORNING CONVECTION COULD BRING IMPACTS TO THESE
TERMINALS, ESPECIALLY KJZI. VCTS WAS INITIALIZED AT KJZI WITH
VCSH AT KCHS WITH TEMPO GROUPS FOR TSRA ROUGHLY 10-14Z. TIMING
MAY NEED TO BE ADJUSTED WITH AMENDMENTS AS TRENDS BECOME MORE
APPARENT. AT KJZI, CONDITIONS WERE LIMITED TO MVFR FOR NOW, BUT
IF CONVECTION CONSOLIDATES THEN PREVAILING WITH OCCASIONAL IFR
OR LOWER CONDITIONS MAY NEED TO BE CONSIDERED. ACTIVITY SHOULD
EXIT THE TERMINALS BY MID-MORNING (14-15Z). FOR THE AFTERNOON,
SHOWERS/TSTMS SHOULD REMAIN WEST OF THE TERMINALS.
KSAV: VFR FOR MUCH OF THE PERIOD. THE RISK FOR SHOWERS/TSTMS
LOOKS TO CONSOLIDATE WEST OF THE TERMINAL THIS AFTERNOON, SO THE
PREVIOUS MENTION OF TSRA WAS REMOVED FOR THE 06Z TAFS.
EXTENDED AVIATION OUTLOOK: PERIODIC FLIGHT RESTRICTIONS ARE
EXPECTED IN SHOWERS AND THUNDERSTORMS THIS WEEK.
MARINE
THROUGH TONIGHT: WIDESPREAD CONVECTION OFFSHORE OF LOWER SOUTH
CAROLINA COAST THIS MORNING WILL POSE HAZARDS TO MARINERS,
INCLUDING GUSTY WINDS, CLOUD-TO-WATERS LIGHTNING, WATERSPOUTS
AND LOCALLY HEAVY RAINFALL REDUCING VSBYS TO 1 NM OR LESS. A
SOUTHERLY FLOW REGIME WILL PERSIST THROUGH TONIGHT AND WINDS
SHOULD AVERAGE 15 KT OR LESS (OUTSIDE OF THE NOCTURNAL SURGE IN
PROGRESS THIS MORNING). WINDS AND SEAS WILL BE HIGHER IN AND
NEAR TSTMS. ANOTHER ROUND OF NOCTURNAL CONVECTION WILL IMPACT
THE WATERS OVERNIGHT INTO EARLY THURSDAY MORNING. SEAS WILL
AVERAGE 2-4 FT.
THURSDAY THROUGH SUNDAY: ATLANTIC HIGH PRESSURE WILL BE THE
DOMINANT SYNOPTIC FEATURE THROUGH THE WEEKEND. THIS WILL
GENERATE A TYPICAL SUMMERTIME WIND FIELD WITH INCREASED WINDS
ALONG THE LAND/SEA INTERFACE EACH AFTERNOON ASSOCIATED WITH THE
SEA BREEZE. MARINE CONDITIONS ARE EXPECTED TO REMAIN BELOW SMALL
CRAFT ADVISORY CRITERIA THROUGH THE WEEKEND.
WATERSPOUTS: FORECAST SOUNDING OUTPUT AND ELEVATED NON-SUPERCELL
TORNADO PARAMETERS VALUES OVER THE NEARSHORE AND OFFSHORE WATERS
LOOK TO SUPPORT A RISK FOR WATERSPOUTS THIS MORNING. A MARINE
WEATHER STATEMENT WAS ISSUED TO ALERT MARINERS TO THIS
POSSIBILITY.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
ST/BRS
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