Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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181 FXUS62 KCHS 282250 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 650 PM EDT Tue May 28 2024 .SYNOPSIS... A cold front will shift offshore tonight. High pressure will build in from the west mid to late week, passing overhead and then offshore over the weekend. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Early this evening: The sea breeze will extend roughly from Jamestown to Summerville, continuing to Jacksonboro and the Beaufort MCAS. It will then be close to US-17 from there on south. There might still be a stray shower or two near and along that boundary. But given weak thermodynamics, there nothing else would occur, as diurnally induced cumulus clouds fade, and winds steadily start to diminish. Tonight: The mid-levels will consist of a longwave trough over the eastern half of the U.S. At the surface, a stationary front meandering along our coast in the early evening will transition into a cold front by late evening, then move further offshore and away from our area. Broad High pressure will be centered over the northern MS Valley overnight, with its periphery building into our region, especially after midnight. The gradient should support very light surface winds, generally from the NW. These winds will continue to usher lower dewpoints into our area along with mostly clear skies. This should yield decent radiational cooling for our area. Lows will range from the lower 60s far inland to the lower 70s at the beaches. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... Zonal flow aloft prevails Wednesday into Thursday before an H5 shortwave dips toward the area from the north late Thursday into Friday. At the surface, troughing persists offshore as high pressure centered over the Great Lakes builds in from the west Wednesday and Thursday. A very weak front will cross the area Friday as the high shifts more over the Northeast and ridges down the coast. Expect dry and warm conditions to prevail Wednesday and Thursday under the strong subsidence aloft. Thursday night and Friday are less certain as modest moisture pooling ahead of the approaching front and modest lift ahead of the approaching shortwave could coincide just enough to initiate some showers and storms sometime Friday morning through afternoon. Have expanded the slight chance POPs some Friday, mainly near the coast, but overall expect moisture to be too limited for much coverage, and mainly dry conditions still on tap for Friday with temps trending closer to normal. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Surface high builds in stronger Saturday and Sunday, then pushes offshore early next week as a series of weak disturbances possibly pass through. The weekend is trending drier with very limited low level moisture available, then have trended toward a more summerlike pattern for early next week, with storm chances mainly along and inland of the sea breeze following a diurnal pattern. Temperatures will be within a few degrees of climo through the period. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... KCHS/KJZI/KSAV: Vfr through 00Z Thursday. Extended Aviation Outlook: VFR. && .MARINE... Tonight: A stationary front meandering along our coast in the early evening will transition into a cold front by late evening, then move further offshore and away from our area. The periphery of broad High pressure will then build into our region, especially after midnight. S-SW winds as high as 15 or 20 kt in the evening will shift to the NW after midnight, generally remaining less than 15 kt. Seas will be 2-3 ft. Wednesday through Sunday: No marine concerns anticipated midweek through the weekend with light to moderate winds prevailing as high pressure builds in from the west through Friday, shifting over the Southeast coast for the weekend. Minimal income swell will keep seas around 2 ft or less through Friday, with seas increasing to 2-4 ft over the weekend with the introduction of medium period northeast swell. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...CEB LONG TERM...CEB AVIATION... MARINE...