697
FXUS62 KCHS 180631 AAA
AFDCHS
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE CHARLESTON SC
231 AM EDT SAT JUL 18 2026
WHAT HAS CHANGED
ALL SECTIONS WERE UPDATED
KEY MESSAGES
- 1) HOT AND HUMID CONDITIONS ARE EXPECTED ACROSS THE AREA THIS
WEEKEND AND THROUGH EARLY NEXT WEEK. HEAT ADVISORIES COULD BE
NEEDED.
DISCUSSION
KEY MESSAGE 1: HOT AND HUMID CONDITIONS ARE EXPECTED ACROSS THE
AREA THIS WEEKEND AND THROUGH EARLY NEXT WEEK. HEAT ADVISORIES
COULD BE NEEDED.
WE CONTINUE TO BE SANDWICHED BETWEEN A RATHER DEEP UPPER TROUGH
OVER THE GREAT LAKES REGION AND RIDGING OUT OVER THE OPEN
ATLANTIC KEEPING US RATHER TOASTY ACROSS THE AREA THROUGH THE
WEEKEND. TO ADD A BIGGER FLY TO THE PROVERBIAL OINTMENT, A
RATHER BROAD BUT WEAK MID LEVEL AREA OF LOW PRESSURE SITTING
OVER THE EASTERN GULF HAS CERTAINLY MADE THINGS A LITTLE TRICKY.
GIVEN ITS PLACEMENT WITHIN THE LARGE SCALE PATTERN IT IS LIKELY
ASSISTING IN KEEPING THE RIDGE IN PLACE AT LEAST FOR A DAY OR
TWO LONGER. COUPLE THIS WITH POSSIBLY SOME EXTRA LATENT HEAT
BEING RELEASED AND VENTILATED TO THE NORTHEAST OF THIS LOW
(THINK OF A CAR ENGINE RELEASING HEAT, BIG CLUSTERS OF STORMS DO
THE SAME) AND ITS EASY TO SEE WHY WE OVERACHIEVED SOME
YESTERDAY ON OUR TEMPERATURES AND HEAT INDICES. WE SAW SOME
AREAS REACH HEAT INDICES OF 110 TO 112 THIS AFTERNOON AS
TEMPERATURES AIDED BY THE STOUT RIDGE CLIMBED INTO THE UPPER 90S
INCLUDING HERE AT CHS. LITTLE CHANGE IS EXPECTED IN THE PATTERN
AND THUS FORECAST FOR TODAY AS THE RIDGE IS STILL FIRMLY IN
CONTROL OVER THE AREA. THE AFOREMENTIONED LOW IS EXPECTED TO
SLOWLY DRIFT JUST A BIT WEST INTO THE GULF LEADING TO EVEN
BETTER QUALITY MOISTURE TO SURGE NORTHWARD INTO THE CAROLINAS.
PWATS ARE EXPECTED TO CLIMB TO AROUND 2 TO 2.1 INCHES TODAY.
THIS INCREASED MOISTURE SHOULD ALLOW FOR DEWPOINTS TO CONTINUE
TO FLIRT IN THE MID TO UPPER 70S INLAND TO LOW 80S ALONG AND
BEHIND THE SEABREEZE. THOSE DEWPOINTS COUPLED WITH BAKING IN THE
SUN SETUP THE PERFECT RECIPE FOR MORE WIDESPREAD HEAT INDICES
IN THE 105 TO 110 RANGE AND EVEN A FEW SPOTS APPROACHING 112
ALONG THE IMMEDIATE COAST. GIVEN WE OVERACHIEVED YESTERDAY, THE
CURRENT FORECAST REFLECTS SOME ADJUSTMENTS TO ACCOUNT FOR THAT
WITHIN THE GUIDANCE AND A HEAT ADVISORY HAS BEEN ISSUED FOR THE
ENTIRE AREA. THE ONLY AREA THAT MAY NOT REACH THE 108 CRITERIA
IS INTERIOR PARTS OF GEORGIA WHERE AFTERNOON STORMS ALONG THE
SEABREEZE COULD OCCUR EARLY ENOUGH TO THWART REACHING THE
OFFICIAL CRITERIA. HOWEVER, CURRENT HI-RES GUIDANCE DOES SUPPORT
YET ANOTHER LATE FIRE (3 TO 4 PM) FOR SEABREEZE STORMS WHICH
COULD BE ENOUGH TIME TO REACH 108. NONETHELESS, WHETHER ITS 105
OR 108 ITS GOING TO FEEL AWFUL OUT ONCE AGAIN.
LOOKING TOWARDS EARLY NEXT WEEK, THE UPPER RIDGE SHOULD FINALLY
BEGIN TO BREAKDOWN AS OUR WANDERING LOW IN THE GULF SLOWLY
MEANDERS WEST TOWARDS LOUISIANA. THIS SHOULD HELP KICK THE REST
OF THE PATTERN EAST A BIT TO INCREASE STORM COVERAGE BY MONDAY.
WHILE HEAT INDICES WILL LIKELY CONTINUE TO HOVER IN AND AROUND
105 TO 108, WE MAY START TO SEE ENOUGH COVERAGE IN STORMS EACH
AFTERNOON TO KEEP THINGS MOSTLY IN CHECK. ANY FURTHER ADVISORIES
WILL LIKELY BE TIED TO HOW EACH DAYS CONVECTION EVOLVES AND
WHAT AREAS ARE EXPECTED TO REMAIN RAIN FREE.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
06Z TAFS: VFR CONDITIONS WILL PREVAIL THROUGH THE PERIOD. HI-RES
GUIDANCE CONTINUES TO INDICATE THAT SEABREEZE SHOULD DEVELOP AND
PROGRESS INLAND BETWEEN 18-19Z. AS THIS BOUNDARY PUSHES INLAND, THE
WINDS SHOULD VEER OUT OF THE SOUTH WITH GUSTS UP TO 21-22 KTS AT
KCHS/KJZI AS THIS BOUNDARY PASSES THROUGH. ALSO, THERE WAS SOME
INDICATION OF THUNDERSTORMS INITIATING OFF THE SEABREEZE IN THE HI-
RES GUIDANCE (ESP. ACROSS SOUTHEAST GEORGIA), THUS A TEMPO WITH TSRA
WAS MENTIONED AT KSAV BETWEEN 21-24Z.
EXTENDED AVIATION OUTLOOK: PREDOMINATELY VFR CONDITIONS THROUGH THE
PERIOD, HOWEVER THERE IS A LOW CHANCE OF BRIEF FLIGHT RESTRICTIONS
EACH AFTERNOON FROM SHOWERS AND THUNDERSTORMS DEVELOPING ALONG THE
SEABREEZE.
MARINE
TODAY: AS THE LOCAL WATERS SITUATE ITSELF BETWEEN AN INLAND
TROUGH AND A SUBTROPICAL HIGH TO THE EAST, THIS WILL ALLOW FOR
THE PRESSURE GRADIENT TO STRENGTHEN THROUGHOUT THE DAY. EXPECT
WIND SPEEDS TO RANGE FROM 15 TO 20 KTS WITH GUSTS UP TO 25 KTS
(ESP. ACROSS THE SOUTH CAROLINA WATERS). THUS, A SMALL CRAFT
ADVISORY (SCA) HAS BEEN ISSUED FOR THE NEARSHORE SOUTH CAROLINA
WATERS (NOT INCLUDING THE CHARLESTON HARBOR) THIS EVENING (8PM)
THROUGH EARLY SUNDAY MORNING. EXPECT SEAS TO RANGE FROM 2 TO 3
FT, BEFORE INCREASING 3 TO 5 FT IN THE NEARSHORE WATERS AND 4 TO
6 FT IN THE OFFSHORE WATERS (HIGHEST ACROSS THE 20-60NM OUT
FROM SOUTH SANTEE, SC TO SAVANNAH, GA).
SUNDAY THROUGH WEDNESDAY: AS THE AFOREMENTIONED INLAND TROUGH
SHIFTS OFFSHORE EARLY NEXT WEEK, THERE'S ANOTHER CHANCE THAT
WE'LL NEED SCAS ON SUNDAY (ESP. ACROSS THE NEARSHORE CHARLESTON
WATERS + CHARLESTON HARBOR). THERE IS A LOW CHANCE (30%) FOR A
LOW PRESSURE SYSTEM TO DEVELOP ACROSS THE NORTHEASTERN GULF THIS
WEEKEND. IF THIS SYSTEM WERE TO TRACK UP THE SOUTHEAST
COASTLINE, THEN WE'LL LIKELY NEED ADDITIONAL WIND AND WAVE
CONCERNS.
CLIMATE
RECORD HIGH MINIMUM TEMPERATURES:
JULY 17:
KCHS: 79/2025
JULY 18:
KCHS: 79/2007
KCXM: 81/2007
JULY 19:
KCHS: 79/1986
KCXM: 83/1986
JULY 20:
KCHS: 79/2025
KCXM: 83/2000
KSAV: 79/1942
JULY 21:
KCHS: 80/1986
KCXM: 83/1998
JULY 22:
KCHS: 81/2011
KCXM: 83/2011
CHS WATCHES/WARNINGS/ADVISORIES
GA...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
GAZ087-088-099>101-114-115-137-216>219-238>241.
SC...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
SCZ040-042>045-147>152.
MARINE...SMALL CRAFT ADVISORY FROM 8 PM THIS EVENING TO 6 AM EDT SUNDAY
FOR AMZ360-362.
BLACK/DENNIS
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