Area Forecast Discussion
Issued by NWS Charleston, SC

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000 FXUS62 KCHS 111427 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1027 AM EDT Tue Aug 11 2020 .SYNOPSIS... The region will remain positioned between Atlantic high pressure well to the east and an inland area of broad low pressure. A weak front could approach the area over the weekend and linger in the vicinity into early next week. && .NEAR TERM /THROUGH TONIGHT/...
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No significant change with the latest update, although did slow down the increase in rain chances this afternoon given the slower heating this morning due to abundant cloud cover. Still some uncertainty regarding how much convection there will be this afternoon as the upper trough/weak low shift more offshore. The lazy sea breeze will be a trigger, possibly differential heating boundaries as well, but not sure how much impact convective boundaries will have. Storm motions will be weak and deep moisture abundant so localized flooding could occur. A few severe storms are possible as well but conditions do not appear to be that supportive for much severe weather. Highs should be in the lower to mid 90s away from the slightly cooler coastal areas. Convection should dissipate this evening with the loss of heating, with focus shifting offshore where the best instability will be. Lows will generally be in the lower to mid 70s inland and upper 70s near the coast.
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&& .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... Surface high pressure will remain over the Atlantic through late week, while troughing/broad low pressure persists inland. Aloft, a weakness in the mid level ridge will linger off the Southeast coast. A moist and unstable airmass will allow at least scattered showers and thunderstorms to develop each day, with coverage peaking in the afternoon and evenings. Some convection is possible overnight as well, but the highest rain chances will generally shift to the coastal waters. No particular day stands out for severe weather, but a stronger storm or two can`t be ruled out especially where boundary interactions occur. In addition, weak storm motions and high moisture content could result in locally heavy rainfall. Otherwise, temperatures will be within a few degrees of normal. Highs will top out in the upper 80s/low 90s with lows overnight in the low to mid 70s. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... Models continue to lack consistency in the long term period. Broad troughing aloft appears to shift towards the East Coast over the weekend into early next week. At the surface, a weak front could approach the region and then linger over or near the area. This setup will generally favor higher than normal rain chances, although given a good amount of disagreement between models, refinements will be needed. Temperatures will be near climo. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... VFR conditions expected to prevail through 12Z Wednesday. Biggest challenge this TAF period is afternoon and evening convection potential. Looks like greatest potential is from around 19Z through 01Z, but anticipated coverage at this point doesn`t warrant the inclusion of VCTS. This may need to be added in a later forecast and there is the possibility of convection at the terminals, especially during the 19Z to 01Z time window. Extended Aviation Outlook: Flight restrictions possible in showers/thunderstorms each day, mainly in the afternoon/evening. && .MARINE...
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Today and Tonight: No significant concerns. Given a weak upper trough across the area and a moist and unstable atmosphere, evening convection over land tonight will likely transition to the coastal waters where it looks like it will be an active night across the waters. Most models show decent amount of convection, so increased rain chances to higher level chance to likely category. Outside of convection, it will be rather tranquil with winds generally at or below 10 knots and seas 1 to 2 feet. Wednesday through Sunday: No marine concerns expected through the period outside of showers/thunderstorms. The waters will remain positioned between high pressure to the east and broad low pressure inland, allowing winds to maintain a southerly component. Speeds will generally be 15 knots or less. Seas will average 2-3 feet.
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&& .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...RJB SHORT TERM...ETM LONG TERM...ETM AVIATION...ETM/MTE MARINE...ETM/RJB

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