574
FXUS62 KCHS 011940
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
340 PM EDT SAT AUG 1 2026
WHAT HAS CHANGED
ALL SECTIONS HAVE BEEN UPDATED.
KEY MESSAGES
- 1) THERE IS RISK FOR LOCALLY HEAVY RAINFALL AND ISOLATED FLASH
FLOODING ACROSS SOUTHEAST GEORGIA INTO THE WESTERN SOUTH
CAROLINA LOWCOUNTRY THIS AFTERNOON AND EVENING. A FEW STRONG
TO MARGINALLY SEVERE THUNDERSTORMS ARE POSSIBLE.
- 2) SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL BRING
THE POTENTIAL FOR HEAVY RAINFALL, LOCALIZED FLOODING, AND/OR
GUSTY WINDS SUNDAY THROUGH EARLY NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: THERE IS RISK FOR LOCALLY HEAVY RAINFALL AND ISOLATED
FLASH FLOODING ACROSS SOUTHEAST GEORGIA INTO THE WESTERN SOUTH
CAROLINA LOWCOUNTRY THIS AFTERNOON AND EVENING. A FEW STRONG TO
MARGINALLY SEVERE THUNDERSTORMS ARE POSSIBLE.
THIS AFTERNOON, REGIONAL RADAR COMPOSITE INDICATED A DEVELOPING BAND
OF THUNDERSTORMS ACROSS SOUTHERN GA, TRACKING NORTHWARD. THESE
STORMS WILL LIKELY CONTINUE NORTHWARD ACROSS THE FORECAST AREA,
PARTIALLY SUPPORTED BY MLCAPE BETWEEN 2500-3000 J/KG. ALSO, WITH THE
ARRIVAL OF THE THUNDERSTORMS, PW VALUES WILL BUILD TO 2 TO 2.2".
THESE STORMS AND ASSOCIATES COLD POOL MAY INTERACT WITH THE SEA
BREEZE TO PRODUCE NUMEROUS TO WIDESPREAD SHOWERS AND THUNDERSTORMS
DURING THE LATE AFTERNOON AND EVENING HOURS. HIGH RESOLUTION
GUIDANCE INDICATES THAT MULTIPLE CELL MERGERS OR TRAINING STORMS MAY
OCCUR, ESPECIALLY IN THE VICINITY OF THE COLD POOL AND SEA BREEZE.
THESE PROCESSES COULD RESULT IN LOCAL AREAS OF 2 TO 4 INCHES OF RAIN
THIS AFTERNOON AND EVENING. THE AREA OF HEAVIEST RAINFALL POTENTIAL
WAS HIGHLIGHTED WELL WITH THE 12Z HREF, INDICATING A 50% OF 3"/3HR
ALONG AND WEST OF I-95 ACROSS SE GA/SC. THUNDERSTORMS SHOULD
GRADUALLY DISSIPATE DURING THE MID TO LATE AFTERNOON. HOWEVER, THE
APPROACH OF A LONGWAVE H5 TROUGH MAY TRIGGER ADDITIONAL SHOWERS AND
THUNDERSTORMS ALONG THE COAST.
KEY MESSAGE 2: SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL
BRING THE POTENTIAL FOR HEAVY RAINFALL, LOCALIZED FLOODING, AND/OR
GUSTY WINDS SUNDAY THROUGH EARLY NEXT WEEK.
SUNDAY: AS THE AFOREMENTIONED SYSTEM CONTINUES TO TREK EASTWARDS,
THE REGION REMAIN IN THE WARM SECTOR OF THE SURFACE LOW PRESSURE
MOVING ACROSS THE OHIO RIVER VALLEY, WITH MID-LEVEL TROUGHING
EXPECTED TO CONTINUE THROUGHOUT THE DAY. PWATS ARE EXPECTED TO
REMAIN HIGH BETWEEN 2.2 - 2.4 INCHES (ABOVE THE 90TH PERCENTILE OF
CLIMATOLOGY), AND WHEN COMBINED WITH THE WARM AIR ADVECTION ALOFT
AND SCATTERED SHORTWAVES, SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE EXPECTED THROUGHOUT THE DAY. CAPE PROFILES REMAIN
LONG AND SKINNY THROUGH THE DAY, WHICH INDICATES POTENTIAL FOR HEAVY
RAINFALL. HREF HAS SCATTERED 70% CHANCES FOR AN INCH IN 3 HOURS WITH
VERY ISOLATED 10% CHANCES FOR 3 INCHES, WHILE THE REFS HAS LESSER
CHANCES FOR AN INCH (40-50%) THOUGH STILL ISOLATED 10% CHANCES FOR 3
INCHES. AS FOR THE SEVERE POTENTIAL, WITH 1500-2000 J/KG OF ML CAPE,
HIGHEST IN THE LATE MORNING TO MID AFTERNOON HOURS, THERE REMAINS
POTENTIAL FOR ISOLATED STRONG TO SEVERE THUNDERSTORMS. GIVEN THE
POTENTIAL FOR HEAVY DOWNPOURS AMIDST A DCAPE ENVIRONMENT OF 500-1000
J/KG, STRONG WIND GUSTS REMAIN THE PRIMARY RISK. THE RISKS FOR BOTH
HEAVY RAINFALL AND SEVERE POTENTIAL ARE HIGHEST FOR OUR INLAND
AREAS, LOWEST FOR AREAS ALONG THE COAST.
MONDAY: THE AFOREMENTIONED SURFACE LOW PRESSURE MOVES NORTHEAST INTO
THE QUEBEC PROVINCE, WITH THE TRAILING COLD FRONT EXTENDING DOWN
INTO GEORGIA AND SOUTHERN ALABAMA. ALOFT, THE TROUGH TURNS INTO A
CLOSED UPPER LEVEL LOW, WITH SCATTERED SHORTWAVES CONTINUING TO
OVERSPREAD THE REGION FROM SOUTH TO NORTH. PWATS DECREASE INTO THE
2.0-2.2" RANGE, AND INSTABILITY WANES TO NEAR 1000 J/KG, DECREASING
BOTH THE HEAVY RAINFALL AND SEVERE WEATHER RISKS. HOWEVER, GIVEN THE
EXPECTED PRECEDING RAINFALL, THE CHANCES FOR LOCALLY HEAVY RAINFALL
WILL PERSIST ESPECIALLY FOR AREAS THAT SAW RECENT HEAVY RAINS.
TUESDAY INTO THE MIDDLE OF THE WEEK: PREVIOUSLY, MODELS BROUGHT THE
COLD FRONT THROUGH THE REGION BRINGING AN END TO THE WET CONDITIONS,
THOUGH THE LATEST 12Z GUIDANCE NOW HAS THE FRONT STALLING OFF TO OUR
WEST AS A SURFACE HIGH PRESSURE BUILDS AND MOVES IN FROM THE
ATLANTIC.
AVIATION /19Z SATURDAY THROUGH THURSDAY/
18Z TAFS: THE PRIMARY CONCERN THIS AFTERNOON WILL BE THE POTENTIAL
FOR THUNDERSTORMS AT THE TERMINALS. THUNDERSTORMS MAY DEVELOP NEAR
THE SEA BREEZE THIS AFTERNOON, POSSIBLY IMPACTING KCHS AND KSAV FROM
19-21Z. FOLLOWING THE SEA BREEZE, SSE WINDS MAY INCREASE TO 15 TO 20
KTS. THE WINDS GUSTS SHOULD DECREASE THIS EVENING. THE APPROACH OF A
LONGWAVE H5 TROUGH MAY TRIGGER ADDITIONAL SHOWERS AND THUNDERSTORMS
ALONG THE COAST. THIS CONVECTION WILL BE HIGHLIGHTED WITH A PROB30
FROM 9-12Z.
EXTENDED AVIATION OUTLOOK: PERIODIC FLIGHT RESTRICTIONS ARE EXPECTED
IN SHOWERS AND THUNDERSTORMS THROUGH EARLY NEXT WEEK. LOCALLY HEAVY
RAINFALL MAY PRODUCE BRIEF IFR OR LOWER VISIBILITY RESTRICTIONS.
MARINE
THIS AFTERNOON: THE NATIONAL WEATHER SERVICE DOPPLER RADAR AND
SATELLITE IMAGES INDICATED A BOUNDARY WITH ISOLATED SHOWERS NEAR
THE ENTRANCE OF THE CHARLESTON HARBOR. THIS LINE WAS ASSOCIATED
WITH A OBSERVED WATERSPOUT ON FOLLY BEACH AT 233 PM. THIS
BOUNDARY SHOULD CONTINUE TO DRIFT NORTH THROUGH 430 PM. THE
ENVIRONMENT MAY SUPPORT THE FORMATION OF ADDITIONAL WATERSPOUTS
ALONG THE BOUNDARY THIS AFTERNOON.
TONIGHT, THE PATTERN WILL SUPPORT SOUTHWEST WINDS BETWEEN 15 TO 20
KTS. WAVE HEIGHTS ARE FORECAST TO BUILD TO 2 TO 4 FT BY LATE TONIGHT.
SUNDAY THROUGH THURSDAY: THE PRESSURE GRADIENT WILL STRENGTHEN
SUNDAY AS BROAD LOW PRESSURE DEVELOPS INLAND WITH AN APPROACHING
FRONT AND HIGH PRESSURE REMAINING IN THE ATLANTIC. SOUTHWESTERLY
WINDS WILL INCREASE DURING THE AFTERNOON, WITH FREQUENT GUSTS
BETWEEN 25 AND 30 KT EXPECTED ACROSS THE LOCAL WATERS. IN ADDITION,
WAVE HEIGHTS ARE FORECAST TO INCREASE TO 4 TO 7 FEET SUNDAY EVENING.
SMALL CRAFT ADVISORIES HAVE BEEN ISSUED FOR THE NEARSHORE MARINE
ZONES OUT TO 20 NM AND THE OUTER GEORGIA WATERS FROM 20-60 NM, AS
WELL AS THE CHARLESTON HARBOR. CONDITIONS SHOULD GRADUALLY IMPROVE
MONDAY NIGHT, WITH BENIGN WIND AND SEA CONDITIONS EXPECTED FOR
TUESDAY THROUGH THE REST OF THE PERIOD.
RIP CURRENTS: GUSTY SOUTHWEST WINDS COMBINED WITH A 6 TO 7 SECOND
SWELL AND WAVE HEIGHTS OF 4-5 FEET WILL SUPPORT AN ELEVATED RIP
CURRENT RISK ON SUNDAY. A MODERATE RISK OF RIP CURRENTS HAS BEEN
EXPANDED TO INCLUDE THE SOUTHEAST GEORGIA BEACHES, REMAINING ACROSS
THE SOUTHEAST SOUTH CAROLINA BEACHES. FOR MONDAY, MODERATE RISK OF
RIP CURRENTS CONTINUE FOR AREAS FROM COASTAL COLLETON COUNTY DOWN TO
THE ALTAMAHA RIVER, WITH A HIGH RISK OF RIP CURRENTS RISK FOR THE
CHARLESTON COUNTY COASTLINE AS STRONGEST WINDS OCCUR ALONG THE
CHARLESTON COUNTY COAST.
CLIMATE
RECORD HIGH MINIMUM TEMPERATURES:
AUGUST 1:
KCHS: 81/1999
KCXM: 86/1999
KSAV: 79/2020
AUGUST 2:
KCHS: 79/2022
KCXM: 84/1999
KSAV: 80/1886
AUGUST 5:
KCHS: 79/1980
KCXM: 82/1991
KSAV: 80/1883
AUGUST 6:
KCHS: 79/1991
KCXM: 82/2006
KSAV: 80/1899
AUGUST 7:
KCHS: 79/2007
KCXM: 83/2007
KSAV: 80/1879
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON SUNDAY TO 2 AM EDT MONDAY FOR
AMZ340.
SMALL CRAFT ADVISORY FROM NOON SUNDAY TO 2 AM EDT TUESDAY FOR
AMZ360-362.
SMALL CRAFT ADVISORY FROM NOON SUNDAY TO 8 AM EDT MONDAY FOR
AMZ364.
SMALL CRAFT ADVISORY FROM NOON SUNDAY TO NOON EDT MONDAY FOR
AMZ384.
APT/NED
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