Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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404 FXUS62 KCHS 152012 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 412 PM EDT Sat Jun 15 2024 .SYNOPSIS... A weak cold front will linger over the area this weekend before slowly lifting back northward early next week. High pressure will then ridge in from offshore mid to late next week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... This Evening: A weak cold front located just to our north will slowly move southward, likely reaching our northern SC counties around sunset. Afternoon radar imagery indicates isolated to scattered convection developing north of our area and moving southward. This matches up fairly well with the CAMs and the HRRR. Though, they have slight differences on the coverage. Either way, we`re expecting isolated to maybe scattered convection through this evening, mainly over our SC counties. Afternoon surface temperatures are peaking in the upper 90s, except cooler at the beaches. Likewise, SPC Mesoscale Analysis indicates MLCAPEs up to 1,000-1,500 J/kg across our northernmost counties, which is a bit higher than earlier today. DCAPEs will be around 1,000 J/kg. So while there is a lot of mid-level dry air in place per the model soundings, any stronger storms that manage to develop could generate strong to damaging winds. The convection will gradually decrease into this evening. Tonight: Mid-level ridging and a broad 592 dam High will gradually build over the Southeast. The cold front will likely be over our northern SC counties later this evening. It`s expected to slowly move south, and stall near the SC/GA border by daybreak Sunday. Little to no convection is expected over land areas overnight. Though, there could be some convection across the coastal waters. Lows will generally range from the lower 70s far inland to the mid 70s along the immediate coast. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... Sunday: Aloft, a strong mid-upper lvl ridge will prevail, remaining centered over the Southeast United States. At the sfc, high pressure centered across New England will slowly build south across the Southeast, nudging a cold front into the region that eventually stalls across the local area. Much of the area should remain rain- free, but sufficient moisture and instability should support few to scattered showers and thunderstorms during the afternoon into early evening, mainly away from the coast. Conditions will remain warm as well, with high temps in the low-mid 90s, warmest inland. Overnight lows will also remain mild, generally in the upper 60s/lower 70s inland to mid-upper 70s near the coast. Monday and Tuesday: Aloft, the pattern will remain similar with a ridge of high pressure elongated across the Northeast to Southeast United States that results in large scale subsidence locally. At the sfc, a stalled front will become more diffuse and/or lift back north of the area early week before high pressure builds across the region from the Atlantic by Tuesday. There are some hints of weak coastal troughing developing along the southern periphery of the ridge just off the Southeast Coast, which could result in some showers and/or thunderstorms across coastal areas, mainly south of Beaufort, SC and into southeast Georgia each afternoon/evening. High temps in the upper 80s nearshore to lower 90s inland Monday should trend a degree or two cooler on Tuesday with an onshore flow in place. Overnight lows will range in the mid-upper 60s well inland to low-mid 70s closer to the coast Monday night. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... Upper ridging shifts north mid-to-late week, with height falls aloft leading to diminishing upper subsidence. At the surface, high pressure migrates off the Northeast coast and toward a more seasonable Bermuda High location. Expect the forecast to trend back toward a more summer-like precip pattern, with scattered afternoon thunderstorms along and inland of the sea breeze and lesser storm activity overnight. Temps remain within a few degrees of normal. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... 18Z TAFs: Mainly VFR. Isolated convection associated with an approaching cold front could approach KCHS and KJZI this afternoon and evening. However, the probabilities of direct impacts to either TAF site remains too low to include a mention of VCTS for now. Will amend if radar trends show otherwise. Any convection is expected to dissipate later this evening, with the overnight being dry. Extended Aviation Outlook: Mainly VFR at KCHS/KJZI/KSAV terminals, but there will be low probabilities for brief flight restrictions due to showers and/or thunderstorms impacting the terminals each afternoon/evening. Highest chances for flight restrictions should occur at the KSAV terminal. && .MARINE... Tonight: A weak cold front is expected to move south through our waters late, possibly stalling near the SC/GA line around daybreak Sunday. Sustained winds from the S or SE in the evening will veer overnight, becoming E by daybreak Sunday. Seas should average 2-3 ft. Sunday through Wednesday: The pressure gradient will remain fairly weak through Monday as a front becomes nearly stationary across the area and begins to deteriorate. However, a modest uptick in wind speeds (especially near the coast) and gradually building seas is anticipated early into the middle of next week as the pressure gradient is somewhat enhanced by high pressure extending across the area from the north and perhaps weak coastal troughing occurring along its southern base along the Southeast Coast. During this time, east-northeast winds could gust to 15-20 kt with seas building upwards to 3-5 ft, largest across offshore GA waters. Southeast swell is anticipated to increase during the second half of next week, which could prompt Small Craft Advisories for 6 ft seas. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...DPB LONG TERM...DPB AVIATION...DPB MARINE...DPB