Area Forecast Discussion
Issued by NWS Charleston, SC

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000 FXUS62 KCHS 171409 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1009 AM EDT Tue May 17 2022 .SYNOPSIS... High pressure will gradually build into the region through the end of the week. A cold front will approach the region this weekend, bringing unsettled weather to the area. && .NEAR TERM /THROUGH TONIGHT/...
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The cold front has cleared the area, allowing high pressure to build into the region today. No weather concerns with dry weather and mostly sunny skies. Not much of a drop in temperature, however it will be less humid than previous days. Highs are forecast to peak in the upper 80s to around 90. Tonight: High pressure will prevail with quiet conditions dominating. The boundary layer will decouple this evening with light/calm winds prevailing for many areas once the sea breeze circulation breaks down. Some patchy fog could form early Wednesday morning across mainly the eastern third of the forecast area where elevated dewpoints will be left in the wake of the sea breeze. Lows will range from the lower 60s well inland and across the Francis Marion National Forest to the upper 60s/near 70 at the beaches and Downtown Charleston.
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&& .SHORT TERM /WEDNESDAY THROUGH FRIDAY/... A strengthening Bermuda High will largely dominate the surface pattern. Increasing ridging aloft and plenty of dry air above H85 will keep rain chances non-existent through Friday, which will not help mitigate the current drought conditions across the forecast area. Some lower-level fair weather cumulus could develop during the afternoon periods. However, model soundings indicate a slight subsidence inversion through the period, indicative of a fairly stable environment. The most notable feature of the short-term forecast are above-normal temperatures. Highs are expected to reach the low to mid 90s Wednesday, cooler at the beaches. Mid to upper 90s are expected for Thursday and Friday. Some places south of the Altamaha River could even reach a few degrees shy of 100F Thursday, which is looking to be the hottest day of the trio. The only sign of respite will occur from dew points generally ranging 55-60 degrees at the hottest locations during peak heating, keeping heat indices below 100 degrees. Warm overnight conditions are expected Wednesday and Thursday with lows only dipping into the upper 60s to the low 70s. There is a possibility that new record highs and/or record high min temperatures could be set Thursday and/or Friday (see the Climate section below). && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... The next chance for any decent rainfall looks to be Saturday as return flow advects deep Gulf moisture into the region. A cold front will then approach the region Sunday and showers/thunderstorms are possible ahead of the advancing front. Unsettled weather could persist through early next week as deep moisture lingers and a potential coastal trough develops. Above normal temperatures will persist through the weekend before dropping to below normal early next week. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... KCHS/KJZI/KSAV: VFR will prevail. Shallow ground fog will be possible at all three terminals early Wednesday morning, but no major impacts are expected. Extended Aviation Outlook: Other than the chance of patchy fog with low vsbys/cigs at the terminals early Wednesday morning, VFR conditions will prevail through the week. Brief flight restrictions are possible in showers/thunderstorms over the weekend. && .MARINE...
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Through Tonight: North to northeast winds will veer to the east this afternoon as high pressure builds in from the north and a sea breeze develops along the coast. Speeds will average 10-15 kt, although locally higher winds will be possible along the land/sea interface and Charleston Harbor as the sea breeze moves inland. Seas will average 2-4 ft. Fairly light south to southeast winds of less than 10 kt will dominate tonight with seas 2-3 ft. Wednesday through Sunday: Surface high pressure will prevail across the southern Atlantic. Benign marine conditions are expected initially with light winds generally 10 knots or less. By Thursday morning, southwest winds will increase through the day as the pressure gradient briefly pinches across the waters. By Thursday evening, gusts could reach up to 25 kt and Small Craft Advisories could be needed through the night. Thereafter, southwest winds around 15 knots will prevail. Seas will average 2-3 feet with 4 footers entering the local waters briefly Thursday night. Rip Currents: There looks to be enough lingering astronomical influences and wind with the sea breeze to support a moderate risk for rip currents along the Georgia beaches today. Although a 2 second, 8 period swell will impact all beaches, slightly lower winds along the South Carolina coast should keep the rip current risk generally in the low category.
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&& .TIDES/COASTAL FLOODING... Another round of coastal flooding will occur across the coast with this evening`s high tide cycle. Data support levels reaching into the moderate level in Charleston Harbor so a Coastal Flood Advisory will be needed. Farther south, tides are expected to peak right at or just above minor coastal flooding levels at Fort Pulaski. A Coastal Flood Advisory may be needed from Beaufort County, SC, through McIntosh County, GA. Additional minor to perhaps moderate coastal flooding will be possible during the late evening high tides through the end of the week due to astronomical influences, mainly for Coastal Colleton and Charleston Counties. Although, less favorable southerly winds should help mitigate the effects of coastal flooding. && .CLIMATE... May 19 Record High Temperatures: KCHS: 96/1996 KSAV: 97/1996 May 20 Record High Min Temperatures: KCHS: 72/1997 May 20 Record High Temperatures: KCHS: 97/1938 KSAV: 96/2006 && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...ETM SHORT TERM... LONG TERM... AVIATION... MARINE... TIDES/COASTAL FLOODING... CLIMATE... is the U.S. government's official web portal to all federal, state and local government web resources and services.