633
FXUS62 KCHS 080014
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
814 PM EDT FRI AUG 7 2026
WHAT HAS CHANGED
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 00Z TAF ISSUANCE.
KEY MESSAGES
- 1) THERE IS THE POTENTIAL FOR LOCALIZED HEAVY RAINFALL EARLY
SATURDAY MORNING ACROSS THE FORECAST AREA, ESPECIALLY ALONG
THE COASTAL COUNTIES.
- 2) THE TYPICAL SUMMERTIME PATTERN WILL CONTINUE THIS WEEKEND
INTO NEXT WEEK. THE THREAT FOR ISOLATED STRONG TO SEVERE
THUNDERSTORMS AND LOCALIZED HEAVY RAINFALL WILL EXIST EACH
DAY.
- 3) MINOR COASTAL FLOODING POSSIBLE ALONG THE SOUTH CAROLINA
COAST WITH EVENING HIGH TIDE CYCLES NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: THERE IS THE POTENTIAL FOR LOCALIZED HEAVY RAINFALL
EARLY SATURDAY MORNING ACROSS THE FORECAST AREA, ESPECIALLY ALONG
THE COASTAL COUNTIES.
AN INVERTED SURFACE TROUGH IS FORECAST TO MEANDER CLOSER TOWARDS
THE SE COASTLINE TONIGHT AND INTO EARLY SATURDAY MORNING. THIS
FEATURE WILL SERVE AS THE MAIN DRIVER OF POTENTIAL SHOWERS AND
TSTORMS EARLY SATURDAY MORNING, AS CONVECTION OVER THE MARINE
WATERS PUSHES ONSHORE. THE HREF IS THE MOST AGGRESSIVE OF THE
CAMS, AND FEATURES THE EARLIEST ARRIVAL TIMING WITH THE HEAVY
RAIN POTENTIAL, WITH THE 12Z HREF FROM TODAY (8/7) SHOWING THE
PROBABILITY OF >2" ALONG THE COASTAL COUNTIES AS ROUGHLY 20-30%.
THE 12Z HRRR IS SLIGHTLY SLOWER THAN THE HREF WITH BRINGING THE
CONVECTION ONSHORE, BUT STILL FEATURES THE THREAT OF HEAVY
RAINFALL. THE WEATHER PREDICTION CENTER HAS HIGHLIGHTED MOST OF
THE LOCAL FORECAST AREA IN A SLIGHT RISK FOR EXCESSIVE RAINFALL
TOMORROW (SATURDAY). GIVEN THE UNCERTAINTY REGARDING THE TIMING
THE FORECAST FEATURES THE RAW NBM, WHICH SEEMED TO BE A GOOD
AVERAGE OF THE GUIDANCE, WITH SHOWERS/TSTORMS MOVING ONSHORE
ROUGHLY IN THE 6-8AM TIMEFRAME. RAINFALL TOTALS ARE FORECAST TO
BE 0.5-1", WITH LOCALLY HIGHER AMOUNTS (HIGHEST ALONG THE
COAST).
KEY MESSAGE 2: THE TYPICAL SUMMERTIME PATTERN WILL CONTINUE THIS
WEEKEND INTO NEXT WEEK. THE THREAT FOR ISOLATED STRONG TO
SEVERE THUNDERSTORMS AND LOCALIZED HEAVY RAINFALL WILL EXIST
EACH DAY.
FOR SUNDAY AND MONDAY, HIGH PRESSURE RIDGING IN FROM OFFSHORE AND
VERY WEAK TROUGHING INLAND WILL BRING MAINLY SCATTERED, DIURNALLY
DRIVEN CONVECTION. A FEW STRONGER TO MARGINALLY SEVERE STORMS ARE
POSSIBLE EACH AFTERNOON, BUT THE OVERALL SEVERE RISK IS LOW.
ADDITIONALLY, WITH VERY LIGHT FLOW THROUGHOUT THE CLOUD LAYER, SLOW
STORM MOTIONS WILL BE THE NORM, AND LOCALLY HEAVY RAINFALL WILL
OCCUR UNDER THE STRONGEST STORMS. EXPECT HEAT INDEX VALUES TO REACH
100-105 EACH AFTERNOON, WITH SOME LOCATIONS POTENTIALLY THREATENING
THE 108 HEAT ADVISORY CRITERIA ALONG THE HWY 17/SEA BREEZE CORRIDOR
EACH AFTERNOON.
UPPER SUBSIDENCE STRENGTHENS BY THE MIDDLE OF NEXT WEEK, RESULTING
IN A MODEST REDUCTION IN AFTERNOON THUNDERSTORM COVERAGE, BUT WARMER
TEMPS AND GREATER HEAT INDEX VALUES. TUESDAY THROUGH THURSDAY
LOOK TO BRING MORE COVERAGE OF 105-110 HEAT INDEX VALUES,
ESPECIALLY CLOSER TO THE COAST. CONTINUE TO MONITOR FORECAST
UPDATES FOR THIS POTENTIAL PERIOD OF DANGEROUS HEAT.
KEY MESSAGE 3: MINOR COASTAL FLOODING POSSIBLE ALONG THE SOUTH
CAROLINA COAST WITH EVENING HIGH TIDE CYCLES NEXT WEEK.
PERIGEAN NEW MOON WILL BRING ELEVATED TIDAL RANGES NEXT WEEK. EVEN
MODEST TIDAL DEPARTURES DURING THE EVENING HIGH TIDE CYCLES MONDAY
THROUGH THURSDAY WOULD BRING TIDAL LEVELS APPROACHING OR EXCEEDING
MINOR COASTAL FLOODING THRESHOLDS. CONTINUE TO MONITOR FORECAST
UPDATES THROUGH THE WEEKEND AS THE TOTAL WATER LEVEL FORECAST GETS
REFINED.
AVIATION /00Z SATURDAY THROUGH WEDNESDAY/
VFR CONDITIONS SHOULD PREVAIL AT CHS/JZI/SAV TERMINALS THROUGH MUCH
OF TONIGHT, GENERALLY THROUGH 09-10Z SATURDAY. CHANCES FOR SHOWERS
AND THUNDERSTORMS INCREASE APPROACHING DAYBREAK AT ALL TERMINALS,
LIKELY IMPACTING JZI INITIALLY (~11Z), THEN AT SAV/CHS DURING
THE FOLLOWING 1-2 HOURS. ROUNDS OF SHOWERS/THUNDERSTORMS ARE
THEN POSSIBLE AT ALL TERMINALS MID-MORNING INTO EARLY AFTERNOON
HOURS, WHICH SHOULD PRODUCE TEMPO MVFR CONDITIONS (POSSIBLY IFR
DURING HEAVY RAINFALL) AT TIMES, WHICH IS INCLUDED IN TEMPO AND
PROB30 GROUPS AT ALL TERMINALS. ACTIVITY SHOULD THEN SHIFT
INLAND RETURNING CONDITIONS TO VFR BY AROUND 20Z SATURDAY AT ALL
TERMINALS.
EXTENDED AVIATION OUTLOOK: PERIODIC FLIGHT RESTRICTIONS ARE EXPECTED
IN SHOWERS AND THUNDERSTORMS THIS WEEK AND INTO THIS WEEKEND.
MARINE
THROUGH TONIGHT: QUIET CONDITIONS ARE EXPECTED INTO TONIGHT. AS
AN INVERTED TROUGH, MEANDERS TOWARDS THE SE COAST OVERNIGHT,
SHOWERS AND THUNDERSTORMS ARE FORECAST TO DEVELOP OVER THE
MARINE WATERS. THESE SHOWERS/TSTORMS WILL PERSIST ACROSS THE
MARINE WATERS INTO SATURDAY MORNING.
SATURDAY THROUGH TUESDAY: ATLANTIC HIGH PRESSURE WILL BE THE
DOMINANT SYNOPTIC FEATURE THROUGH THE WEEKEND. LIGHT TO MODERATE
WINDS PREVAIL WITH GUSTY WINDS ALONG THE LAND/SEA INTERFACE EACH
AFTERNOON ASSOCIATED WITH THE SEA BREEZE. BE ALERT FOR THE POTENTIAL
FOR NOCTURNAL JETTING TO SET UP SUNDAY INTO EARLY NEXT WEEK, KEEPING
BREEZY CONDITIONS IN PLACE ALONG THE BEACHES OVERNIGHT. THIS FEATURE
IS TYPICALLY POORLY RESOLVED BY MODELS, BUT THE COMBINATION OF THE
WEAK SURFACE TROUGH SHIFTING INLAND WITH PERSISTENT STRONG HIGH
PRESSURE OFFSHORE AND VERY WARM WATER MAKES FOR A FAVORABLE
SETUP.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
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