030  
FXUS62 KCHS 201423  
AFDCHS  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHARLESTON SC  
1023 AM EDT WED MAY 20 2026  
   
WHAT HAS CHANGED  
 
FOG HAS DIMINISHED, REMOVED MENTION FROM THE DISCUSSION.  
 
 
   
KEY MESSAGES  
 
- 1) RAIN CHANCES LIKELY TO INCREASE LATE IN THE WEEK, THOUGH  
NO HAZARDOUS WEATHER IS ANTICIPATED AT THIS TIME.  
 
 
   
DISCUSSION  
 
KEY MESSAGE 1: RAIN CHANCES LIKELY TO INCREASE LATE IN THE  
WEEK, THOUGH NO HAZARDOUS WEATHER IS ANTICIPATED AT THIS TIME.  
 
THE AREA WILL REMAIN ALONG THE WESTERN FLANKS OF ATLANTIC HIGH  
PRESSURE CENTERED WELL OFFSHORE. EARLY MORNING WATER VAPOR  
IMAGERY SHOWS A WELL DEFINED TROPICAL UPPER TROPOSPHERIC TROUGH  
(TUTT) LOW POSITIONED NEAR 29N/75W AT 20/06Z. BROAD SUBSIDENCE  
ALOFT ALONG THE WESTERN FLANKS OF THE TUTT WILL CONTINUE TO  
RESIDE OVER THE AREA THROUGH TONIGHT WITH SUBTROPICAL RIDGING  
PROGGED TO HOLD ALOFT ACROSS MUCH OF THE SOUTHEAST STATES. THE  
TUTT IS FORECAST TO SLOWLY WEAKEN AND REMAIN WELL OFFSHORE AS  
THE IT PROPAGATES WEST/NORTHWEST ALONG THE BACKSIDE OF THE  
SUBTROPICAL ANTICYCLONE MEANDERING NEAR BERMUDA. THE NET RESULT  
WILL BE A CONTINUATION OF WARM, RAIN-FREE CONDITIONS WITH SOME  
HIGH CLOUDS SPREADING IN AT TIMES.  
 
LOW-LEVEL THICKNESSES ARE PROGGED TO MAX OUT ABOUT 10-30 METERS  
HIGHER THAN TUESDAY AS SUBSIDENCE ALOFT BUILDS. HIGHS ARE POISED  
TO WARM INTO THE LOWER-MID 90S INLAND WITH UPPER 70S/NEAR 80 AT  
THE BEACHES. TEMPERATURES ACROSS THE COASTAL COUNTIES WILL  
REMAIN WHAT SOMEWHAT TEMPERED AS ANOTHER ROBUST, PURE SEA BREEZE  
CIRCULATION PROPAGATES STEADILY INLAND THROUGH THE AFTERNOON.  
SIMILAR TO THE PAST FEW NIGHTS, IT WILL TAKE UNTIL THE EARLY  
MORNING HOURS THURSDAY BEFORE THE BOUNDARY FULLY DECOUPLES AND  
INFLUENCES FROM THE AFTERNOON SEA BREEZE WANE. LOWS WILL RANGE  
FROM THE MID 60S INLAND TO THE LOWER 70S AT THE BEACHES. LOW-  
LEVEL MOISTURE PROFILES AND 1000 HPA CONDENSATION PRESSURE  
DEFICITS DO NOT LOOK AS FAVORABLE FOR FOG DEVELOPMENT COMPARED  
TO THIS MORNING, BUT SOME SHALLOW GROUND FOG APPEARS LIKELY,  
ESPECIALLY AWAY FROM THE IMMEDIATE COAST.  
 
UPPER LEVEL RIDGING LINGERS ACROSS THE SOUTHEASTERN CONUS  
THURSDAY, AS A SFC COLD FRONT STALLS OUT ALONG THE TENNESSEE  
RIVER VALLEY. AS SUCH, SHOULD SEE LARGELY DRY CONDITIONS PREVAIL  
ACROSS OUR AREA, WITH HIGHS FORECAST TO RISE INTO THE LOWER 90S  
UNDER MOSTLY SUNNY SKIES.  
 
WILL SEE THE AFOREMENTIONED COLD FRONT SAG SOUTHWARD OVER THE  
CAROLINAS BY FRIDAY, CAUSING THE UPPER LEVEL RIDGE TO SHIFT OVER  
THE ATLANTIC. WHILE THE EXACT POSITION OF THE FRONT AND HOW FAR  
SOUTH IT PROGRESSES WILL BE THE KEY FACTOR IN DETERMINING  
RAINFALL COVERAGE AND AMOUNTS, CURRENT TRENDS CONTINUE TO FAVOR  
A STRONG ATLANTIC RIDGE. THIS WOULD KEEP THE FRONT DISPLACED  
JUST TO OUR WEST AND NORTH, AND THUS LIMIT OUR CHANCES FOR  
SEEING MEANINGFUL RAINFALL. ENSEMBLE GUIDANCE CONTINUES TO  
FOLLOW THIS TREND AS WELL, WITH PROBABILITIES FOR SEEING  
RAINFALL GREATER THAN AN INCH THROUGH SATURDAY REMAINING LESS  
THAN 25%. SO, WHILE TRENDS CURRENTLY FAVOR A DRIER, LESS  
IMPACTFUL EVENT, STILL ENCOURAGE FOLKS TO MONITOR THE LATEST  
FORECAST AS SUBTLE SHIFTS IN TRACK MAY STILL OCCUR. OTHERWISE,  
EXPECT THE SEVERE POTENTIAL WITH ANY SHOWER/STORM TO REMAIN LOW,  
GIVEN THE LACK OF FORCING AND MOISTURE IN PLACE.  
 
 
   
AVIATION /14Z WEDNESDAY THROUGH SUNDAY/  
 
20/12Z TAF DISCUSSION:  
KCHS/KJZI/KSAV: FOG WILL QUICKLY MIX OUT AFTER DAYBREAK WITH VFR  
CONDITIONS. SHALLOW GROUND OF WILL BE POSSIBLE AT ALL THREE  
TERMINALS AGAIN EARLY THURSDAY MORNING.  
 
EXTENDED AVIATION OUTLOOK: THERE ARE NO HIGH CONFIDENCE  
CONCERNS.  
 
 
   
MARINE  
 
THROUGH TONIGHT: QUIET CONDITIONS WILL PERSIST WITH THE REGION  
POSITIONED ALONG THE WESTERN FLANKS OF ATLANTIC HIGH PRESSURE  
CENTERED WELL OFFSHORE. EAST/SOUTHEAST WINDS WILL PREVAIL WITH  
SPEEDS LESS THAN 15 KT, ALTHOUGH SOME LOCAL ENHANCEMENT ALONG  
THE LAND/SEA INTERFACE AND CHARLESTON HARBOR WILL LIKELY OCCUR  
WITH THE SEA BREEZE. SEAS WILL AVERAGE 2-4 FT.  
 
THURSDAY THROUGH SUNDAY: NO MARINE CONCERNS ARE EXPECTED. HIGH  
PRESSURE TO THE EAST WILL DRIVE ONSHORE EAST-SOUTHEASTERLY FLOW  
EACH DAY, WITH WIND SPEEDS MOSTLY TOPPING OUT IN THE 10-15 KNOT  
RANGE. EACH AFTERNOON AND EVENING THERE COULD BE SOME LOCAL  
ENHANCEMENT ALONG THE LAND/SEA INTERFACE WITH THE DIURNAL SEA  
BREEZE. SEAS WILL AVERAGE 2-4 FEET THROUGH THE PERIOD.  
 
RIP CURRENTS: A LINGERING 9 SEC, 2-3 FT SWELL WILL KEEP A  
MODERATE RIP CURRENT RISK IN PLACE FOR ALL BEACHES THROUGH THIS  
EVENING.  
 
 
   
CHS WATCHES/WARNINGS/ADVISORIES  
 
GA...NONE.  
SC...NONE.  
MARINE...NONE.  
 
 
 
 
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