FXUS62 KCHS 040558 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1258 AM EST Wed Dec 4 2024 .SYNOPSIS... High pressure will prevail through mid week. A cold front will push across the area Thursday, with the return of high pressure into the weekend. A storm system could impact the area early next week. && .NEAR TERM /THROUGH TODAY/... Low level warm advection will negate some of the effects of otherwise excellent radiational cooling through the overnight. Our 850 mb temperatures rise about 2-3C between now and daybreak, which will prevent the vast majority of the forecast counties from reaching the Cold Weather Advisory criteria of 20F. That said, a few of the coldest parts of our northwest tier of zones still might hit 20F, but those values will general be very localized and would be very brief. In general, 21-26F will prevail inland from US-17, where freezing temperatures will persist through about 9 AM. Closer to the coast, upper 30s and lower 30s will be common, with the freezing line down close to the Intra-Coastal Waterway. && .SHORT TERM /TONIGHT THROUGH FRIDAY/... Mostly quiet weather will prevail for the short term period. Modified arctic high pressure will propagate across the Southeast U.S. Wednesday. The high will meander offshore Wednesday night into Thursday as another cold front approaches. The front looks to pass offshore Thursday night, crossing in a typical two piece fashion as it bends around the southern Appalachians. The low-level flow veers westerly pretty quickly ahead of the front, thus limiting deep moisture return as the boundary meanders through. This should curtail rain chances quite a bit, especially with little to no deep- layered forcing noted in the various model cross sections. While a brief sprinkle or two could occur, especially over interior Southeast Georgia Thursday afternoon, the risk for measurable rainfall looks too low mention at this time. The front will clear the coast Thursday night with a reinforcing shot of post-frontal cold air advection dominating into Friday. Highs Wednesday will warm into the mid 50s, then peaking in the 60s Thursday before cooling back into the upper 40s/lower 50s for Friday. Lows Thursday morning will drop into the mid-upper 30s inland to around 50 at the coast with upper 20s inland to the mid-upper 30s at the beaches for Friday morning. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... High pressure will prevail for much of the extended period as upper ridging builds aloft. A potent southern stream storm system could impact the region early next week bringing with it the next chance for meaningful rainfall. Temperatures will steadily moderate through the period with highs returning to the 70s Monday and Tuesday. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... VFR conditions will prevail at KCHS, KJZI, and KSAV through 06Z Thursday. Extended Aviation Outlook: Gusty conditions associated with a cold front are possible at all terminals Thursday. && .MARINE... Overnight: The arctic high should be centered right over the region, resulting in northerly winds no higher than 10 or 15 kt. With the offshore flow, seas will be just from 2-3 ft in the nearshore waters and 3-4 ft in the offshore Georgia waters. Wednesday through Sunday: Southwesterly winds will increase Wednesday night into Thursday ahead of the front, possibly reaching Small Craft Advisory thresholds, especially over the South Carolina nearshore and Georgia offshore legs. Elevated northerly winds will persist after FROPA Thursday evening into Friday within a post- frontal cold air advection regime. Winds will weaken Saturday before backing more westerly by Sunday. Seas look to peak Thursday morning, 3-6 ft, highest over the South Santee-Edisto Beach out 20 NM leg. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...ST LONG TERM...ST AVIATION... MARINE...