186
FXUS62 KCHS 221143
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
743 AM EDT WED JUL 22 2026
WHAT HAS CHANGED
THE AVIATION SECTION WAS UPDATED TO REFLECT THE 12Z TAFS.
KEY MESSAGES
- 1) SMOKE FROM THE HORSE ISLAND WILDFIRE WILL IMPACT PORTIONS
OF BERKELEY COUNTY TONIGHT INTO WEDNESDAY.
- 2) HOT AND HUMID CONDITIONS ACROSS COASTAL SOUTH CAROLINA AND
GEORGIA THROUGH MID-WEEK. HEAT ADVISORIES COULD BE NEEDED.
- 3) A SLOW-MOVING COLD FRONT WILL BRING INCREASING CHANCES FOR
SHOWERS AND THUNDERSTORMS LATE THIS WEEK THROUGH THE WEEKEND,
WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL.
DISCUSSION
KEY MESSAGE 1: SMOKE FROM THE HORSE ISLAND WILDFIRE WILL IMPACT
PORTIONS OF BERKELEY COUNTY TONIGHT INTO WEDNESDAY.
THE HORSE ISLAND WILDFIRE NEAR SHULERVILLE, SC HAS INCREASED TO 1200
ACRES. A DENSE SMOKE ADVISORY HAS BEEN REQUESTED BY THE U.S. FOREST
SERVICE FOR PORTIONS OF BERKELEY COUNTY IN RESPONSE TO THE WILDFIRE
SMOKE. THE LATEST HYSPLIT OUTPUT SHOWS THE WORST OF THE SMOKE WILL
REMAIN ACROSS BERKELEY COUNTY, BETWEEN JAMESTOWN AND THE CHARLESTON
BORDER, EXTENDING NORTHEAST ACROSS THE SANTEE RIVER INTO PORTIONS OF
GEORGETOWN AND WILLIAMSBURG COUNTIES. VISIBILITIES MAY DROP BELOW 1
MILE AT TIMES OVERNIGHT, ESPECIALLY ALONG PARTS OF HIGHWAY 45. ROAD
CLOSURES ARE POSSIBLE. SMOKE WILL LIKELY REMAIN AN ISSUE INTO
WEDNESDAY ALTHOUGH VISIBILITIES SHOULD IMPROVE SOME BY MID-MORNING
AS DISPERSION INCREASES AND MIXING HEIGHTS RISE.
KEY MESSAGE 2: HOT AND HUMID CONDITIONS ACROSS COASTAL SOUTH
CAROLINA AND GEORGIA THROUGH MID-WEEK. HEAT ADVISORIES COULD BE
NEEDED.
HOT AND HUMID CONDITIONS ARE EXPECTED TO CONTINUE OVER THE NEXT 48
HOURS AS THE FORECAST AREA REMAINS ON THE WESTERN PERIPHERY OF
THE UPPER RIDGE. WITH DECREASED MOISTURE COMPARED TO PREVIOUS
FORECASTS, DEWPOINTS ARE EXPECTED TO CONTINUE TO MIX INTO THE
LOW 70S ACROSS INLAND AREAS KEEPING HEAT INDICES IN THE 100 TO
105 RANGE FOR MOST OF THE AREA TODAY. WHILE THESE VALUES WILL
STILL MAKE THINGS RATHER UNCOMFORTABLE THEY ARE NOT QUITE HEAT
ADVISORY CRITERIA. CLOSER TO THE COAST, CONDITIONS WILL BE
DETERMINED BY THE MOVEMENT OF THE AFTERNOON SEABREEZE. AS IT
MOVES SLOWLY INLAND EACH AFTERNOON, DEWPOINTS WILL SURGE INTO
THE UPPER 70S BEHIND THE BOUNDARY LEADING TO HEAT INDICES IN THE
105 TO 108 RANGE. HOWEVER, THIS WILL LIKELY ONLY BE FOR A
COUPLE HOURS DURING THE LATE AFTERNOONS LEADING TO LOWER
CONFIDENCE IN REACHING ADVISORY CRITERIA LONG ENOUGHT.THURSDAY
WILL BE MUCH OF THE SAME WITH DEWPOINTS MIXING OUT INLAND AND
DESPITE AIR TEMPERATURES HEATING UP INTO LIKELY THE UPPER 90S,
HEAT INDICES LIKELY TOP OUT ONCE AGAIN IN THE 105 TO 108 RANGE.
HOWEVER, IF MOISTURE BEGINS TO COME IN A LITTLE MORE IMPRESSIVE
AND DEWPOINTS DO NOT MIX INTO THE LOW 70S THEN SOME
CONSIDERATIONS FOR AN ADVISORY WOULD BE NEEDED.
DESPITE NOT HAVING ANY HEAT ADVISORIES, CONDITIONS WILL STILL REMAIN
RATHER UNCOMFORTABLE AND WITH DEWPOINTS IN THE UPPER 70S OVERNIGHT
VERY LITTLE RELIEF WILL OCCUR EACH NIGHT. GIVEN WE HAVE SET RECORD
HIGH MINIMUM TEMPERATURES THE LAST FEW NIGHTS, CONTINUED HEAT STRESS
THROUGH THE MIDDLE OF THE WEEK CAN BE DANGEROUS TO VULNERABLE
COMMUNITIES INCLUDING ELDERLY AND THOSE WHO DO NOT HAVE ACCESS TO
ADEQUATE COOLING. THE EXTREME HEAT IS EXPECTED TO COME TO AN END BY
THE END OF THE WEEK AS INCREASING RAIN CHANCES ARRIVE WITH A SLOW
MOVING FRONT.
KEY MESSAGE 3: A SLOW-MOVING COLD FRONT WILL BRING INCREASING
CHANCES FOR SHOWERS AND THUNDERSTORMS LATE THIS WEEK THROUGH THE
WEEKEND, WITH THE POTENTIAL FOR LOCALLY HEAVY RAINFALL.
AS A MID-LVL TROUGH SITUATES ITSELF ACROSS THE EASTERN SEABOARD
TODAY AND TOMORROW (THURSDAY), AN ASSOCIATED COLD FRONT WILL SLOWLY
PROGRESS TOWARDS THE REGION, REACHING THE AREA ON THURSDAY BEFORE
STALLING NEARBY THROUGH THE WEEKEND. FORECAST SOUNDINGS CONTINUE TO
INDICATE A VERY MOIST AIRMASS, WITH PWAT VALUES INCREASING TO AROUND
2.2 INCHES ON FRIDAY AND UP TO 2.4 INCHES THIS WEEKEND. THIS
COMBINED WITH SKINNY CAPE PROFILES WILL FAVOR EFFICIENT RAINFALL
PRODUCTION AND INCREASE THE POTENTIAL FOR LOCALIZED FLOODING. WHILE
MOST FLOODING IMPACTS ARE EXPECTED TO REMAIN MINOR, REPEATED HEAVY
DOWNPOURS OVER URBAN AREAS SUCH AS THE CHARLESTON, OR SAVANNAH METRO
AREAS COULD WARRANT FLOOD ADVISORIES AND/OR EVEN FLASH FLOOD
WARNINGS.
ALTHOUGH STILL SUBJECT TO CHANGE, RAINFALL TOTALS OF COUPLE INCHES
ARE POSSIBLE FRIDAY THROUGH SUNDAY, WITH THE HIGHEST AMOUNTS OF ~3-4
INCHES POSSIBLE IN THE PROXIMITY OF THE FRONTAL BOUNDARY.
ADDITIONALLY, LOCALLY HIGHER TOTALS WILL BE POSSIBLE WHERE
THUNDERSTORMS REPEATEDLY TRAIN OVER THE SAME LOCATION. THE WEATHER
PREDICTION CENTER (WPC) HIGHLIGHTS PORTIONS OF THE REGION (MAINLY
ACROSS THE SOUTH CAROLINA LOWCOUNTRY) IN A SLIGHT RISK OF EXCESSIVE
RAINFALL ON THURSDAY, AND THEN MARGINAL RISK OF EXCESSIVE RAINFALL
FOR MAJORITY OF THE REGION ON FRIDAY AND SATURDAY.
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
12Z TAFS: VFR CONDITIONS SHOULD PREVAIL ACROSS THE AREA THROUGH
THE MORNING. SOME MVFR CEILINGS MAY BE POSSIBLE ALONG COASTAL
SOUTH CAROLINA OVER THE NEXT COUPLE OF HOURS POSSIBLY IMPACTING
JZI/CHS FROM ROUGHLY 14 TO 16Z. AN ISOLATED SHOWER OR TWO COULD
ACCOMPANY THE LOWER CEILINGS BEFORE CLEARING BY 16 TO 17Z.
WINDS WILL REMAIN OUT OF THE SOUTH AT AROUND 10 KNOTS INCREASING
TO AROUND 15 KNOTS BEHIND THE AFTERNOON SEABREEZE. GUSTS TO 20
TO 25 KNOTS COULD BE POSSIBLE BEHIND THE SEABREEZE DURING THE
AFTERNOON BEFORE DIMINISHING AROUND 02Z.
EXTENDED AVIATION OUTLOOK: CHANCES OF FLIGHT RESTRICTIONS INCREASE
LATER THIS WEEK WITH A GREATER COVERAGE OF SHOWERS/THUNDERSTORMS.
MARINE
TODAY: BREEZY SOUTH-SOUTHEASTERLY WINDS WILL CONTINUE ACROSS THE
LOCAL WATERS AS A COLD FRONT APPROACHES FROM THE NORTH AND EAST-WEST
SURFACE RIDGE REMAINS TO THE SOUTH. THIS WILL MAINTAIN HAZARDOUS
CONDITIONS THROUGH THURSDAY MORNING. SMALL CRAFT ADVISORIES ARE IN
EFFECT FOR ALL MARINE ZONES THROUGH THURSDAY MORNING. AS SOUTH-
SOUTHWESTERLY SWELL TAPERS BACK, SEAS WILL RANGE FROM 3 TO 5 FT.
THURSDAY THROUGH SUNDAY: SMALL CRAFT ADVISORIES ARE EXPECTED TO END
BY THURSDAY MORNING. AS THE AFOREMENTIONED FRONT STALLS IN THE
VICINITY, THE PRESSURE GRADIENT WILL RELAX BACK AND MARINE
CONDITIONS SHOULD BECOME RATHER BENIGN THROUGH SUNDAY. SEAS WILL
RANGE FROM 2 TO 4 FT.
RIP CURRENTS: A MODERATE RISK OF RIP CURRENTS IS EXPECTED TO
CONTINUE ALONG THE SOUTH CAROLINA AND GEORGIA BEACHES THROUGH THIS
EVENING. THERE IS ALSO A MODERATE RISK TOMORROW (THURSDAY), HOWEVER
IT IS JUST FOR THE CHARLESTON COUNTY BEACHES. ON WEDNESDAY,
INCREASING SOUTH TO SOUTH-SOUTHWEST WINDS WILL SUPPORT BREAKERS OF 3
TO 4 FT, WITH OCCASIONAL BREAKERS ABOVE 4 FT POSSIBLE AND DOMINANT
WAVE PERIODS OF 6 SECONDS. ALTHOUGH SURF IS EXPECTED TO SUBSIDE A
LITTLE BIT ON THURSDAY, A LONGER-PERIOD SWELL OF AROUND 8 SECONDS
SHOULD CONTINUE TO SUPPORT DANGEROUS RIP CURRENTS (ESP. FOR THE
CHARLESTON COUNTY BEACHES).
CLIMATE
RECORD HIGH TEMPERATURES:
JULY 23:
KCHS: 99/2015
JULY 27:
KSAV: 100/2010
RECORD HIGH MINIMUM TEMPERATURES:
JULY 22:
KCHS: 81/2011
KCXM: 83/2011
JULY 23:
KCHS: 80/1991
KCXM: 83/1952
JULY 24:
KCHS: 81/2024
JULY 25:
KCHS: 80/2011
KCXM: 82/2016
KSAV: 80/1893
JULY 26:
KCHS: 78/2025
JULY 27:
KSAV: 80/1885
JULY 28:
KCHS: 80/2025
KCXM: 84/2025
KSAV: 81/1878
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...DENSE SMOKE ADVISORY UNTIL 10 AM EDT THIS MORNING FOR SCZ045.
MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EDT THIS MORNING FOR AMZ340.
SMALL CRAFT ADVISORY UNTIL 5 AM EDT THURSDAY FOR AMZ360-362.
SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR AMZ364-384.
BLACK/DENNIS
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