722
FXUS62 KCHS 311314
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
914 AM EDT THU JUL 31 2025
...HEAT ADVISORY EXPANDED INLAND WITH AN UPGRADE TO AN EXTREME
HEAT WARNING FOR MUCH OF THE GEORGIA AND FAR SOUTHERN SOUTH
CAROLINA COAST...
SYNOPSIS
ATLANTIC HIGH PRESSURE PREVAILS OFFSHORE THROUGH THE REST OF
THE WORK WEEK, AS A TROUGH OF LOW PRESSURE PRESSES INLAND. A
COLD FRONT MAY STALL NEARBY THIS WEEKEND AND PROMOTE HEAVY TO
EXCESSIVE RAINFALL ACROSS THE REGION.
NEAR TERM /THROUGH TONIGHT/
TODAY: THE CENTER OF THE SUBTROPICAL ANTICYCLONE ALOFT IS
POSITIONED JUST OFFSHORE OF CAPE CANAVERAL THIS MORNING AND WILL
MAINTAIN ITS INFLUENCE ON THE REGION TODAY. GOES-E VISIBLE
IMAGERY SHOW SUNNY TO MOSTLY SUNNY SKIES PREVAILING WITH SOME
CIRRUS BLOW-OFF FROM CONVECTION JUST OFFSHORE OF THE NORTHEAST
SOUTH CAROLINA COAST OOZING INTO THE CHARLESTON TRI-COUNTY.
CIRRUS SHOULD THIN WITH TIME AS CONVECTION TO THE NORTH WANES
AND A DIURNAL CUMULUS FIELD FORMS ACROSS THE AREA. TEMPERATURES
AT 31/13Z WERE RUNNING ABOUT 2-4 DEGS WARMER THAN 24 HOURS AGO
AND THIS TREND WILL PERSIST INTO THE AFTERNOON. HIGHS ARE ON
TARGET TO TOP OUT IN THE MID-UPPER 90S, BUT SOME SLIGHT UPWARD
ADJUSTMENTS WERE NEEDED WELL INLAND WITH AN UPDATE THIS MORNING.
SOME DEGREE OF CAPPING/SUBSIDENCE ASSOCIATED WITH THE UPPER HIGH
TO THE SOUTH WILL KEEP CONDITIONS DRY FOR MUCH OF THE MORNING
AND WELL INTO THE AFTERNOON HOURS. RAP MODIFIED SOUNDINGS DO SHOW
THE CAP EVENTUALLY BEING OVERCOME, BUT MODEL 850 HPA THETA-E
VALUES WILL FAIRLY LOW CONSIDERING THE TIME OF YEAR. THIS
SUGGESTS THE MID-LEVELS MAY BE A BIT TOO DRY TO SUPPORT A
SIGNIFICANT AMOUNT OF CONVECTION. FOR NOW, NO POP ADJUSTMENTS
WERE MADE BUT THE POPULATED 01Z NBM POPS COULD BE ON THE HIGH
SIDE.
DEWPOINTS WILL MIX OUT A BIT THIS AFTERNOON, BUT TYPICAL
DEWPOINT POOLING BACK INTO THE UPPER 70S/LOWER 80S WITH THE SEA
BREEZE LOOKS LIKELY AGAIN AT THE COAST. WITH A LACK OF
CONVECTION UNTIL LATE, THE POTENTIAL FOR HEAT INDICIES REACHING
108 ACROSS THE INTERIOR HAS INCREASED. THE HEAT ADVISORY HAS
THEREFORE BEEN EXPANDED WEST TO INCLUDE THE FAR INLAND TIER. AT
THE COAST, SEVERAL SITES WERE VERY NEAR WARNING CRITERIA FOR A
FEW HOURS YESTERDAY EVEN WITH POCKETS OF CONVECTION. GIVEN HIGHS
WILL BE A FEW DEGREES WARMER WITH SIMILAR DEWPOINTS, THE RISK
FOR SEEING HEAT INDICES 113 OR HIGHER FOR AT LEAST 2 HOURS HAS
INCREASED ENOUGH TO UPGRADE THE HEAT ADVISORY TO AN EXTREME
WARNING FOR ALL COASTAL ZONES, INCLUDING INLAND CHATHAM COUNTY
AND MUCH OF THE SAVANNAH METRO. EXPECT HEAT INDICES OF 108-112
IN THE HEAT ADVISORY AREA WITH 112-116 IN THE EXTREME HEAT
WARNING AREA. VALUES OF 105-109 ARE MORE LIKELY AT THE BEACHES.
TONIGHT: HREF AND SOME INDIVIDUAL CAMS INDICATING SCATTERED
CONVECTION COULD LINGER WELL INTO THE EVENING BEFORE
DISSIPATING. OTHERWISE,ANOTHER VERY WARM/MUGGY NIGHT WITH LOWS
IN THE MID 70S WELL INLAND, THE UPPER 70S TO LOWER 80S EAST AND
COASTAL AREAS.
SHORT TERM /FRIDAY THROUGH SUNDAY/
LOOK FOR ANOTHER HOT AND HUMID DAY TO PREVAIL FRIDAY, AHEAD OF OF AN
ADVANCING COLD FRONT. SIMILAR TO DAYS PAST, HAVE AFTERNOON HIGHS
SURGING INTO THE MID TO UPPER 90S, WITH PEAK HEAT INDICES UP TO 112
DEGREES. THUS, ADDITIONAL HEAT ADVISORIES MAY BE NEEDED, BUT THESE
WILL LARGELY BE DRIVEN BY THE TIMING AND EXTENT OF AFTERNOON
CONVECTION - SO STAY TUNED FOR FUTURE UPDATES!
IN TERMS OF PRECIPITATION, LATEST CAMS KEEP CONDITIONS FAIRLY QUIET
THROUGHOUT THE DAYLIGHT HOURS FRIDAY, WITH CONVECTION THEN
BLOSSOMING NEAR SUNSET AS THE AFOREMENTIONED FRONT SLIDES ACROSS THE
REGION. WILL LIKELY SEE PRECIPITATION HOLD STEADY FOR MUCH OF THE
OVERNIGHT PERIOD, WITH A SLIGHT LULL IN ACTIVITY SATURDAY MORNING.
RENEWED CHANCES THEN RETURN OVER THE WEEKEND AS THE FRONT STALLS
ALONG THE COAST, WHICH COUPLED WITH ABUNDANT MOISTURE WILL SUPPORT
MODERATE TO HEAVY DOWNPOURS CAPABLE OF PRODUCING FLASH FLOODING.
WHILE RAINFALL TOTALS (2 TO 5 INCHES) HAVEN'T DEVIATED MUCH SINCE
THE LAST PACKAGE, DO THINK IT'S WORTH NOTING THAT CONFIDENCE STILL
REMAINS FAIRLY LOW ON WHERE THE HIGHEST TOTALS WILL OCCUR - AS THIS
EVENT WILL LARGELY BE CONTINGENT ON WHERE THE FRONT STALLS.
LATEST TRENDS WOULD SUGGEST A SOUTH/SOUTHEASTWARD SHIFT, PLACING THE
HIGHER TOTALS ACROSS SOUTHEASTERN GEORGIA - THOUGH THIS AXIS COULD
STILL WOBBLE IN THE COMING DAYS. SO, IN SHORT, DO EXPECT TO SEE
AREAS OF LOCALLY HEAVY RAINFALL ACROSS THE REGION THROUGHOUT THE
WEEKEND - THOUGH AMOUNTS AND LOCATION ARE STILL SUBJECT TO CHANGE.
WHETHER YOU ARE TRAVELING, HAVE OUTDOOR PLANS, OR JUST LIVE IN THE
AREA - WE ENCOURAGE YOU TO STAY UP TO DATE WITH THE LATEST FORECAST
AND HAVE A PLAN SHOULD FLOODING OCCUR.
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/
DREARY CONDITIONS CONTINUE MONDAY AS THE FRONT REMAINS IN OUR
VICINITY. AGAIN, COULD SEE A SLIGHT LULL IN ACTIVITY DURING THE
MORNING HOURS, BEFORE BETTER CHANCES (50-80%) ARRIVE DURING THE
AFTERNOON. OTHERWISE, LOOK FOR ACTIVE WEATHER TO CONTINUE THROUGH
MID-WEEK AS THE SYNOPTIC PATTERN HOLDS STEADY ACROSS THE REGION. ON
A POSITIVE NOTE, THIS PATTERN WILL ALLOW FOR A REFRESHING CHANGE OF
COOLER TEMPERATURES, AS HIGHS IN THE LOW TO MID 80S AND LOWS IN THE
70S BECOME COMMON.
AVIATION /13Z THURSDAY THROUGH MONDAY/
TODAY: EXPECT VFR TO PREVAIL ALL SITES THROUGH THE EARLY
AFTERNOON. SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
FORM FROM THE WEST-NORTHWEST, AND MOVE TOWARD THE EAST DURING
THE AFTERNOON. STILL THINK THE BEST CHANCE FOR AFTERNOON
CONVECTION AND BRIEF FLIGHT RESTRICTIONS WILL BE KCHS, AND
POSSIBLY KJZI. LATEST GUIDANCE CONTINUES TO KEEP THE AREA AROUND
KSAV MOSTLY STORM FREE TODAY. HOWEVER, GIVEN THE UNSTABLE
AIRMASS AND OVERALL UNCERTAINTY, WILL STILL LEAVE PROB30 FOR
CONVECTION LATER AFTERNOON INTO EARLY EVENING. FINALLY, THE
PRESSURE GRADIENT WILL TIGHTEN SOME NEAR THE COAST THIS
AFTERNOON, AND HAVE LEFT GUSTS TO AROUND 20 KTS FOR KJZI.
TONIGHT: GUIDANCE INDICATING THAT SCATTERED SHOWERS/THUNDERSTORMS
COULD PERSIST WELL INTO THE EVENING BEFORE DISSIPATING,
ESPECIALLY AROUND KCHS AND KJZI. A RETURN TO VFR CONDITIONS IS
EXPECTED ALL SITES LATER IN THE EVENING/AFTER MIDNIGHT.
EXTENDED AVIATION FORECAST: THE RISK FOR FLIGHT RESTRICTIONS
DUE TO SHOWERS/TSTMS WILL PERSIST EACH AFTERNOON/EVENING WITH
CHANCES RAMPING UP OVER THE WEEKEND.
MARINE
TODAY AND TONIGHT: NO HIGHLIGHTS ARE EXPECTED. ATLANTIC HIGH
PRESSURE WILL REMAIN TO THE EAST-SOUTHEAST OF THE WATERS WITH A
TROUGH OF LOW PRESSURE INLAND. THIS WILL KEEP GENERALLY SOUTH-
SOUTHWEST WINDS OF 10 TO 15 KNOTS. MODELS SHOW THE PRESSURE
GRADIENT STRENGTHENING THIS AFTERNOON, ESPECIALLY OVER AMZ350
AND 352. SO, HAVE GUSTS NEAR 20 KTS ACROSS THOSE ZONES THIS
AFTERNOON. BY TONIGHT, SOUTHWEST WINDS OF 10 TO 15 KNOTS
CONTINUE. SEAS GENERALLY 2 TO 3 FEET, INCREASING TO 2 TO 4 FEET
LATER TONIGHT.
EXTENDED MARINE: EXPECT SOUTHERLY WINDS AT 10 TO 15 KT THROUGH
FRIDAY, WITH WINDS TURNING TO THE NORTHEAST OVER THE WEEKEND AS A
REASONABLY STRONG COLD FRONT FOR EARLY AUGUST STALLS NEARBY OVER THE
WEEKEND. IT COULD BECOME GUSTY OVER THE WEEKEND (MAINLY ON SUNDAY
AFTERNOON) ACROSS THE NEARSHORE SOUTH CAROLINA WATERS AS THE
GRADIENT PINCHES BEHIND THE COLD FRONT. EXPECT SEAS TO BE 2 TO 3 FT,
AND THEN BEGIN TO BUILD 3 TO 5 FT ON SUNDAY (MAINLY ACROSS SOUTH
CAROLINA NEARSHORE WATERS). OTHERWISE, NO MARINE CONCERNS.
CLIMATE
RECORD HIGH MINIMUM TEMPERATURES:
JULY 31:
KCHS: 80/2022
KSAV: 80/2010
AUGUST 1:
KCHS: 81/1999
KSAV: 79/2020
CHS WATCHES/WARNINGS/ADVISORIES
GA...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR GAZ087-088-
099>101-114>116-137-138-140.
EXTREME HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR
GAZ117>119-139-141.
SC...HEAT ADVISORY UNTIL 8 PM EDT THIS EVENING FOR SCZ040-042>045-
047.
EXTREME HEAT WARNING UNTIL 8 PM EDT THIS EVENING FOR
SCZ048>052.
MARINE...NONE.
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