Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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740 FXUS62 KCHS 070207 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1007 PM EDT Sat Jul 6 2024 .SYNOPSIS... A weak front will remain stalled near the area through much of next week. && .NEAR TERM /THROUGH SUNDAY/... Radar continues to show areas of convection across the Southeast U.S. this evening. While the general trend across the region has been less coverage and weaker convection, that may not be entirely the case for our area. Local radar imagery indicates bands of convection across our far inland counties, moving very slowly to the east. SPC Mesoscale Analysis has MLCAPEs ~1,000 J/kg across these locations, which may be underdone. Luckily, DCAPEs here are only a few hundred, so the severe threat remains low. The expectation is for the instability to gradually weaken over the next few hours, leading to diminishing convection. However, high PWAT values remain in place across the region (almost 2.5" in some locations). So small boundary interactions and outflows are generating new convection in this moisture-rich environment. Even the CAMs have struggled to grasp the convection that is on the radar now, let alone a few hours from now. So the expectation is a few more hours of convection across our far inland counties. Weak steering winds and the high PWATs will support a continued risk for locally heavy rainfall. Flooding of low-lying and poor drainage areas remains a concern. The convection will weaken to stratiform precipitation and then diminish after midnight. Warm and humid conditions will persist overnight with lows ranging from the mid 70s well inland to the lower 80s at the beaches and Downtown Charleston. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... A mid-level ridge present over the forecast area on Sunday will slowly begin to weaken into Tuesday with shortwaves rippling across the southeastern states. At the surface a weak front will linger in the vicinity. The weakening ridge aloft will yield temperatures in the low 90s through the short term period. With dew points in the low to mid 70s heat indices will likely only reach up to 103, shy of Heat Advisory criteria. With the lingering front in the vicinity significant moisture will be available, with PWATs upwards of 2.3- 2.4 inches, which would be close to the maximum PWAT according to SPC Climatology. Scattered to widespread showers and thunderstorms will be possible each afternoon, with the threat of heavy rainfall as PWATs remain elevated. The best coverage for precipitation will be across SE GA, closer to the stalled front and higher PWAT values. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... The ridging aloft will continue to weaken through the end of the week, with additional shortwaves rippling across the southeastern states. Deep moisture will remain in place, with PWATs well above 2 inches. Scattered to widespread showers and thunderstorms are forecast each afternoon, mostly driven by a robust afternoon sea breeze. The current forecast has high temperatures in the low to mid 90s through the week, resulting in heat index values between 100 and 106. Heat Advisories later in the week cannot be ruled out, however at this juncture the forecast keeps conditions below the 108 criteria. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... 00Z TAFs: VFR. While some convection could persist well inland this evening, it`s not expected to impact the TAF sites. Though, convection could impact KSAV on Sunday, so we introduced a VCSH towards the end of the TAF time period. Extended Aviation Outlook: Brief flight restrictions possible in showers and thunderstorms, particularly during the afternoon and early evening. && .MARINE... Tonight: Southerly winds 10-15 kt with seas 2-3 ft will prevail. Sunday through Thursday: Generally tranquil conditions expected across the local marine waters through the period. Winds will average 15 knots or less with seas 2 to 3 ft. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE...