556
FXUS62 KCHS 261103
AFDCHS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON SC
703 AM EDT TUE AUG 26 2025
SYNOPSIS
HIGH PRESSURE WILL PREVAIL THROUGH MID TO LATE WEEK. A WEAK
AREA OF LOW PRESSURE COULD THEN PASS NEARBY LATER THIS WEEK
INTO THE FIRST HALF OF THE WEEKEND.
NEAR TERM /THROUGH TONIGHT/
A WEAK COLD FRONT WILL SLIDE EAST OF THE NEARSHORE COASTAL WATERS
EARLY THIS MORNING. IN THE WAKE OF THE COLD FRONT, HIGH PRESSURE
CENTERED NEAR THE MID-MISSISSIPPI VALLEY WILL GRADUALLY BUILD EAST
ACROSS THE FORECAST AREA. STEADY NORTHWEST WINDS SHOULD CONTINUE
THROUGH EARLY THIS AFTERNOON, BECOMING LIGHT AND VARIABLE LATE THIS
AFTERNOON. AS A RESULT, A DRY AND STABLE PROFILE SHOULD BUILD ACROSS
THE REGION THROUGH THE DAY. THE FORECAST WILL FEATURE MOSTLY SUNNY
CONDITIONS AND LESS THAN 10 POPS. USING A BLEND OF MOS, TEMPERATURES
ARE FORECAST TO PEAK IN THE UPPER 80S ALONG AND NORTH OF THE
SAVANNAH RIVER WITH VALUES AROUND 90 DEGREES SOUTH.
TONIGHT, NEAR TERM GUIDANCE INDICATES THAT A SECONDARY PERIOD OF H85
CAA IS EXPECTED TO DEVELOP AROUND 0Z. IN FACT, NAM12 INDICATES THAT
H85 TEMPS ALONG A LINE FROM KSAV TO KCHS WILL COOL FROM 15C AT 0Z TO
12-13C BY 12Z. THE COMBINATION OF WEAK CAA, MOSTLY CLEAR SKY, AND
LIGHT TO CALM WINDS SHOULD ALLOW TEMPERATURES TO FALL 5 TO 7 DEGREES
BELOW NORMAL. LOW TEMPERATURES ARE FORECAST TO RANGE FROM THE MID
60S INLAND TO NEAR 70 ALONG THE COAST.
SHORT TERM /WEDNESDAY THROUGH FRIDAY/
WEDNESDAY: SURFACE HIGH PRESSURE WILL SHIFT OVER THE OHIO VALLEY AS
A SHORTWAVE EMBEDDED WITHIN AN UPPER-LEVEL TROUGH EXITS OFFSHORE.
THIS PATTERN WILL ALLOW ADDITIONAL DRY AIR, CHARACTERIZED BY PWATS
AROUND 1" OR LESS, TO FILTER INTO THE REGION. EXPECT MOSTLY SUNNY
SKIES WITH NO MENTIONABLE RAIN CHANCES FORECAST. HIGH TEMPERATURES
WILL REACH THE MID 80S ACROSS SOUTHEAST SOUTH CAROLINA AND UPPER 80S
IN SOUTHEAST GEORGIA. A SEASONABLY COOL NIGHT IS ON TAP, WITH LOWS
DIPPING INTO THE MID 60S INLAND AND LOWER 70S ALONG THE COAST. A FEW
OF THE TYPICALLY COOLER INLAND SPOTS COULD EVEN FALL INTO THE LOWER
60S.
THURSDAY AND FRIDAY: HIGH PRESSURE OVER THE NORTHERN TWO-THIRDS OF
THE EASTERN CONUS WILL ERODE THURSDAY AS ANOTHER SHORTWAVE BEGINS TO
DROP IN FROM THE GREAT LAKES REGION. AT THE SAME TIME, MOISTURE WILL
BEGIN TO INCREASE AHEAD OF A BROAD, WEAK SURFACE LOW DEVELOPING NEAR
THE GULF COAST. WHILE INSTABILITY WILL REMAIN LIMITED (CAPE VALUES
200-300 J/KG), STILL EXPECT A SLIGHT INCREASE IN AFTERNOON
SHOWER/THUNDERSTORM ACTIVITY WITH CHANCES PEAKING AROUND 20-30%,
MAINLY ALONG THE SOUTHEAST GEORGIA COAST. SURFACE LOW PRESSURE WILL
THEN SPREAD ACROSS THE FL PENINSULA LATE THURSDAY NIGHT AND COULD
POTENTIALLY MOVE OFF THE FL/GA COAST BY FRIDAY MORNING. OVERALL,
RAIN CHANCES LOOK TO INCREASE FRIDAY MORNING THROUGH THE AFTERNOON.
THIS SEEMS TO BE THE GENERAL CONSENSUS AMONGST MODELS SINCE
SHORTWAVE ENERGY WILL BE MOVING OVER THE AREA DURING THIS TIME AS
WELL, BUT CONVECTION COVERAGE STILL LOOKS A BIT UNCERTAIN SINCE MUCH
ALSO DEPENDS ON THE EVOLUTION OF THE LOW. TEMPERATURES WILL PEAK IN
THE MID TO UPPER 80S THURSDAY, AND A COUPLE DEGREES COOLER FRIDAY
DUE TO INCREASED CLOUD/PRECIP COVERAGE.
LONG TERM /FRIDAY NIGHT THROUGH MONDAY/
UNSETTLED CONDITIONS COULD EXTEND INTO THE WEEKEND AS LOBES OF
VORTICITY CONTINUE TO ROUND THE BASE OF AN AMPLIFIED UPPER TROUGH
OVER THE EASTERN CONUS. THERE IS EVEN POTENTIAL FOR A SECOND AREA OF
WEAK LOW PRESSURE TO FORM OFFSHORE. NBM FORECASTS POPS RANGING FROM
30-40% INLAND TO 50-60% ALONG THE COAST WHICH SEEM REASONABLE GIVEN
THE ANTICIPATED PATTERN. BELOW NORMAL TEMPERATURES WITH HIGHS ONLY
IN THE LOW TO MID 80S ARE CURRENTLY FORECAST THROUGH THE WEEKEND.
AVIATION /11Z TUESDAY THROUGH SATURDAY/
VFR CONDITIONS ARE EXPECTED TO PREVAIL AT CHS/JZI/SAV TERMINALS
THROUGH 12Z WEDNESDAY.
EXTENDED AVIATION FORECAST: VFR CONDITIONS EXPECTED TO LARGELY
PREVAIL, WITH BRIEF PERIODS OF FLIGHT RESTRICTIONS POSSIBLE BY THE
END OF THE WEEK AS CHANCES FOR SHOWERS/STORMS INCREASE.
MARINE
TODAY AND TONIGHT, SFC HIGH PRESSURE WILL GRADUALLY BUILD ACROSS THE
MARINE ZONES. WINDS SHOULD GENERALLY FAVOR A NORTH-NORTHWEST
DIRECTION AT AROUND 10 KTS. SEAS SHOULD RANGE BETWEEN 2-3 FT TODAY,
DECREASING TO AROUND 2 FT TONIGHT.
WEDNESDAY THROUGH SUNDAY: SURFACE HIGH PRESSURE TO THE NORTH WILL
MAINTAIN EAST-NORTHEAST WINDS THROUGH MID TO LATE WEEK. AN AREA OF
LOW PRESSURE FORMING WITHIN THE NORTHERN GULF COULD SPREAD ACROSS
THE FLORIDA PENINSULA AND THEN SHIFT OFFSHORE WITHIN/NEAR THE LOCAL
WATERS BY FRIDAY. SOME UNCERTAINTY ON THE EVOLUTION OF THE LOW HAS
LEFT LITTLE CONSENSUS IN TERMS OF WIND SPEED/DIRECTION THROUGH THE
MAJORITY OF THE WEEKEND. HOWEVER, WE DO NOT ANTICIPATE ANY MARINE
CONCERNS AT THIS TIME.
CHS WATCHES/WARNINGS/ADVISORIES
GA...NONE.
SC...NONE.
MARINE...NONE.
NEAR TERM...NED
SHORT TERM...BRS
LONG TERM...BRS
AVIATION...BRS/NED
MARINE...BRS/NED
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