Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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478 FXUS62 KCHS 300724 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 324 AM EDT Thu May 30 2024 .SYNOPSIS... High pressure will extend across the area through early next week. && .NEAR TERM /THROUGH TONIGHT/... Today: A dry cold front will push south through the area over the next few hours and is on target to clear the Altamaha River just after daybreak. Weak, post-frontal cold air advection will be brief and will become neutral later in the day, but a mean northerly wind component will keep conditions much cooler compared to the past few day where a strong downslope component prevailed. Full sun thickness schemes support highs in the mid- upper 80s which is on track with the 30/00z statistical guidance means. A weak sea breeze will begin to develop along the coast by early afternoon and trek slowly inland through sunset. The only real impact from its passage will an uptick in dewpoints and a veering of the wind from north/northeast to east/southeast. The atmosphere looks too dry to support the development of fair weather cumulus, but occasional strands of high clouds will pass through at times. Tonight: High pressure will build south into the Southeast U.S. tonight. The boundary layer looks to decouple shortly after sunset with the sea breeze circulation quickly breaking down across the coastal counties. Clear skies, low dewpoints and calm/light winds will support strong radiational cooling. Low temperatures favoring the colder side of the 30/00z guidance were used to construct overnight temperatures taking into account usual mesoscale influences and the warmer SSTs at the coast and in the Santee-Cooper Lakes. Similar to this morning, very tight thermal gradients will be observed near bodies of water. Lows will range from the upper 50s/near 60 inland to the lower 70s at the beaches and Downtown Charleston. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... Mid level trough shifts off the East Coast on Friday. Ridging will then briefly traverse overhead early in the weekend, before a weak disturbance moves through on Sunday. At the surface, high pressure initially centered north of the area will eventually drift east and offshore, maintaining control of the local weather. Lack of moisture or any notable forcing will keep quiet and dry conditions through at least Saturday. Could see a few diurnal showers/thunderstorms on Sunday, but even then coverage looks sparse. Rain chances are no higher than 20% and mainly focused over far inland areas. It will feel quite pleasant with highs largely in the mid 80s and low humidity. Low temperatures Friday night will be in the upper 50s to lower 60s, except more mild at the immediate coast. Low temps will gain a couple degrees for Saturday night. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... Atlantic high pressure is expected to extend across the region during the early to middle of next week. Aloft, ridging looks to rebuild over the area, with potential for a weak wave to approach towards midweek. Still no day that looks particularly active. Forecast continues to feature just slight chance/20% PoPs during the day for diurnally-driven showers and thunderstorms. Temperatures will be near to above normal. && .AVIATION /04Z THURSDAY THROUGH MONDAY/... 30/06z TAF Discussion: KCHS/KJZI/KSAV: VFR through 31/06z Extended Aviation Outlook: VFR. && .MARINE... Today: A brief northerly surge will occur this morning behind a cold front. The front will clear the far southern waters shortly after daybreak. North winds will begin to veer to the northeast through the afternoon, veering more east to southeast near the coast and Charleston Harbor as a sea breeze develops. Speeds 15 kt with gusts to 20 kt this morning will diminish to 5-10 kt by this afternoon. Seas will average 2-3 ft. Tonight: After a period of light winds in the evening, a more northerly component will become reestablished as high pressure to the north builds south. Speeds will hold less than 10 kt with seas 1-2 ft. Friday through Tuesday: High pressure initially centered north of the region will shift east and offshore over the weekend. Atlantic high pressure will continue to extend over the area through the middle of next week. Conditions stay below Small Craft Advisory levels through the period, with winds speeds 15 knots or less and seas averaging 2-3 feet. && .EQUIPMENT... The Automated Surface Observing System (ASOS) located at the Savannah/Hilton Head International Airport (KSAV) is scheduled to be powered down tonight due to work being done near the site. Observations will not be available between midnight and 6 AM Friday morning. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$