Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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652 FXUS62 KCHS 300202 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1002 PM EDT Wed May 29 2024 .SYNOPSIS... 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 THURSDAY MORNING/... Late this evening, a sfc cold front was analyzed over the Midlands of SC, sliding towards the coast. The front is timed to slide across the forecast area late this evening, resulting in a subtle wind shift and drier air. IR satellite indicates a wide field of cirrus across the forecast area and upstream over the Deep South. Temperatures are on pace to reach the mid to upper 50s far inland, to around 60 degrees closer to the coast. At the beaches and Downtown Charleston, warm water temperatures will keep air temperatures from dropping as low as they could. These locations should expect lows in the upper 60s. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... A pseudo Omega blocking pattern will be in place across NOAM to start the short term period with ridging from the southern Plains into the Upper Midwest/western Great Lakes anchored by troughs across western Canada/northwest U.S. through New England and the mid Atlantic. Weak surface boundary and suppressed upper level heights/cooler temps aloft will press down through the southeast states for Thursday and Friday which will translate into slightly cooler daytime temperatures with highs running in the middle 80s (83- 87) although pretty close to normal for late May. One more piece of stronger short-wave energy is expected to dive from the Great Lakes and down into and off the Mid Atlantic coast Friday, opening the door for sharper upper level ridging to build through the southeast and Atlantic coast region. Building heights and eventual southerly return flow setting up across the region will trend temperatures warmer through the weekend (and into next week). Overall...dry weather prevails through the short term forecast period. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Sharp upper level ridging and surface high pressure will slowly transition off the coast late in the weekend/early part of the next work week allowing a series of (largely) convectively induced waves to ripple into and through the southeast and mid Atlantic region, although deterministic longer term guidance solutions show quite a bit of spread in the details. Warmer temperatures return and this might open the door for a bit more instability nosing out of the Gulf into the southeast from Sunday onward. Blended model guidance continues to advertise low end diurnal convection chances each afternoon through the long term period, which is fine well inland but might be overdone nearer the coast given model instability profiles/depiction. Better chances across the coastal southeast may not be until midweek. Nonetheless, for forecast consistency, and given climatology heading into June, we have retained low end precip chances each afternoon from Sunday onward. Temperatures for the period start out in the middle 80s but will be warming into the upper 80s to around 90 by midweek. Overnight lows will span the 60s...warmer along the coast. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... 0Z TAFs: VFR. Extended Aviation Outlook: Overall VFR conditions will prevail through the period. && .MARINE... Tonight: Expect SW winds 5-10 kt this evening. A weak and dry cold front will move through around midnight, then quickly shift offshore. Winds will veer behind the front and surge due to some cool air advection. Expect them to be NNW around 15 kt with gusts to 20 kt by daybreak Thursday. Seas 1-2 ft this evening will build to 2-3 ft overnight. Thursday through Monday: No marine concerns through early next week. High pressure initially centered to the northwest will drift east and eventually offshore over the weekend. Wind speeds average 15 knots or less. Seas will run 1-3 feet through the period. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM...Adam LONG TERM...Adam AVIATION...NED MARINE...Adam