Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
898 FXUS62 KCHS 132350 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 750 PM EDT Sun Jul 13 2025 .SYNOPSIS... Weak high pressure will continue to build across the region through the week. && .NEAR TERM /THROUGH MONDAY/... Tonight: Numerous outflow boundaries have spread across the forecast area this afternoon and evening. Deep convection should push south of SE GA by late this evening. The rest of the night appears dry. Some guidance indicates there is some potential for ground fog during the pre-dawn hours Monday morning. We will continue to monitor trends in guidance. Low temperatures should range in the 70s. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... A weak upper-lvl ridge will remain across the Southeast over the next couple of days. Simultaneously, a surface low will try to develop off the Georgia and Florida coastline and track west into the Gulf on Monday night. At the surface, rich moisture will continue to be advected into the region with PWAT values ~2.0 inches. This will be more than enough moisture to spark up some showers and thunderstorms each afternoon as the sea breeze pushes inland. Expect temperatures to be in the mid to upper 90s on Monday, with upper 80s to low 90s on Tuesday and Wednesday. Heat index values on Monday will range from 100 to 106 degree in the afternoon hours (especially in Southeast Georgia). These values remain under Heat Advisory Criteria (108F), therefore we will not be issuing a Heat Advisory for Monday at this time. Deep moisture and moderate instability will support locally heavy rainfall with any shower and/or thunderstorm that develops, and isolated strong to severe thunderstorms are possible each afternoon. Overnight lows will remain mild and only dip into the low to mid 70s (with warmer temperatures closer to the beaches). && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... A deep upper-lvl ridge will develop over the Southeast late this week through the weekend, as an area of low pressure moves westward across the north central Gulf. The Bermuda high will continue to advect an ample amount of moisture across the Southeast with PWAT values remaining ~2.0 inches throughout the period. With moderate instability expected to build in the afternoons, expect typical summertime weather with showers and thunderstorms initiating off the sea breeze each day. Temperatures will remain slightly above normal for this time of the year. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... Prior to the 0Z TAFs, thunderstorms were passing within the vicinity of KSAV. The KSAV TAF will mention of VCTS until 1Z. The rest of the night should yield dry conditions with light northeast winds. Some MOS indicates some potential for low clouds and fog during the pre-dawn hours. Confidence is too low to mention any fog in the TAFs at this time. Showers and thunderstorms should remain concentrated well inland of KCHS and KJZI Monday afternoon. However, deep convection may spread near KSAV by late in the afternoon, highlighted with a mention of VCTS by 22Z. Extended Aviation Outlook: VFR will mainly prevail throughout the period, however brief flight restrictions are possible within showers and thunderstorms that develop in the afternoon and/or evening hours. && .MARINE... This Afternoon and Tonight: Conditions will remain well below Small Craft Advisory criteria through this afternoon and tonight. For the afternoon and evening, winds will flip around to become southerly under the influence of the sea breeze circulation with speeds still mostly 10 knots or less. Right along the land/sea interface speeds could top out in the 10-15 knot range, including Charleston Harbor. Then overnight, winds will continue to be quite weak, diminishing to less than 10 knots. Seas should average around 2 feet, but could be up to 3 feet around the 20 nm line and beyond. Much like the last few days, thunderstorms are expected to develop along or just inland of the coast and then move southward to the coast or out over the coastal waters. Frequent lightning and strong wind gusts will be the primary threats. Monday through Thursday: Expect generally southerly winds at 5 to 10 kt to prevail throughout the period. It could become a bit gusty each afternoon with gusts up to 15 to 20 kt as the seabreeze pushes inland (gusts strongest across the immediate coastline and the Charleston Harbor). Southeasterly swell will continue to mix into the local waters throughout the week. Seas will be 1 to 2 ft, then increase to 2 to 3 ft on Tuesday evening. Otherwise, no marine concerns expected. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM...Dennis LONG TERM...Dennis AVIATION...NED MARINE...CPM/Dennis