Area Forecast Discussion
Issued by NWS Charleston, SC

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000 FXUS62 KCHS 131916 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 316 PM EDT Thu May 13 2021 .SYNOPSIS...
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High pressure will continue building into the region through Friday and will remain the primary weather feature into the middle of next week.
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&& .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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Surface high pressure will extend across the region tonight, while mid level troughing prevails aloft. Quiet and dry weather is expected. Should be a decent set-up for radiational cooling with mostly clear skies and light winds. Temperatures will again fall well below mid-May climatology. Lows are forecast to range from the upper 40s inland to lower/middle 50s at the coast.
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&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
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Friday through Sunday: Overall, very tranquil conditions will persist across the forecast area through the weekend. Aloft, nearly zonal flow will prevail into Sunday, then begin to turn more anticyclonic as shortwave ridging approaches from the west. At the surface, high pressure centered north of the area will track eastward and eventually move off the East Coast. Cool northeasterly low level flow on Friday and Saturday will turn more easterly and onshore by Sunday. The forecast is rain free. Plenty of sun, coupled with increasing low level thickness values should result in a steady warming trend. Friday highs should top out in the mid 70s, which is around 8 degrees below normal. By Sunday, upper 70s to low 80s will be widespread which is still several degrees below normal for mid May.
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&& .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
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The long term period will feature a building ridge aloft with high pressure at the surface generally prevailing through the period. Overall, there is no significant forcing for ascent and most places will likely be precipitation-free through mid week. There are some indications that the potential for isolated convection will increase in the Tuesday-Thursday period, and 20 percent rain chances are in the forecast. Temperatures are expected to steadily warm and should be back into the low to mid 80s by Monday. We will likely see some upper 80s for inland locations Tuesday through Thursday, though areas along the immediate coast will be limited by the prevailing onshore flow.
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&& .AVIATION /19Z THURSDAY THROUGH TUESDAY/...
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VFR is expected through 18z Friday. Extended Aviation Outlook: VFR conditions will prevail.
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&& .MARINE...
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Tonight: Elevated northeast winds are expected to continue tonight in between high pressure over the eastern CONUS and a weak low well offshore. Seas will average 4-7 feet, highest beyond 20 nm. These conditions will maintain Small Craft Advisories over all marine zones, with the exception of the Charleston Harbor. Friday through Tuesday: Strong northeast flow will continue on Friday with gusts to 25 knots and seas 4-6 feet for the nearshore waters and 5-7 feet for the outer waters. Small Craft Advisories remain in effect for all waters outside Charleston Harbor through Friday evening when the nearshore waters will come down. The advisory for the outer Georgia waters will continue through much of Saturday due to lingering 6 ft seas. Thereafter, east to southeasterly winds will top out in the 10-15 knot range through Tuesday. Seas should average 2-4 feet. Rip Currents: A moderate risk of rip currents continues for all beaches through Friday. Northeast winds won`t be quite as strong by Saturday, so the rip risk will likely be right on the threshold between a low and moderate risk. Will continue to highlight this possible elevated risk in the Hazardous Weather Outlook.
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&& .CHS WATCHES/WARNINGS/ADVISORIES...
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GA...None. SC...None. MARINE...Small Craft Advisory until 8 PM EDT Friday for AMZ350-352-354. Small Craft Advisory until 5 PM EDT Saturday for AMZ374.
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&& $$ NEAR TERM...ETM SHORT TERM...BSH LONG TERM...BSH AVIATION...BSH/ETM MARINE...BSH/ETM

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