FXUS62 KCHS 111654 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1154 AM EST Mon Dec 11 2023 .SYNOPSIS... Cool high pressure will build over the area this week. A coastal low pressure system may impact the area next weekend. && .NEAR TERM /THROUGH TONIGHT/... No changes are needed for the noon update. The forecast is on track. Today: The cold front is now well offshore with post-frontal cold air advection (CAA) in progress. The degree of CAA will wane through the day. It will be a chilly day despite near full insolation with highs generally peaking in the mid-upper 50s. Tonight: The center of high pressure is expected to remain over the southern Appalachians. There should be enough pressure gradient to support a NE winds between 3-5 mph through the night. Otherwise, conditions will be favorable for radiational cooling, clear sky with a very dry environment. Using a blend of MOS, low temperatures are forecast to range from the upper 20 inland to the upper 30s along the coast. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... Cool and dry high pressure will expand across the area from the northwest. Mostly sunny skies expected Tuesday, then extensive high cirrus will overspread the area Tuesday night and continue through Thursday. Downslope flow will help push highs into the mid/upper 50s Tuesday and lower 60s Wednesday. We'll lose the downslope component on Thursday as a reinforcing cold front drops through from the north, so Thursday will mainly be in the mid 50s. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... The forecast remains fairly uncertain late week into next weekend due to model differences regarding a possible coastal low. We stuck pretty close to the NBM for PoPs brings slight chance showers Saturday and chance showers Sunday into Monday. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... 11/18z TAF discussion: KCHS/KJZI/KSAV: VFR through 12/18z. Extended Aviation Outlook: VFR. && .MARINE... Today: Conditions will gradually improve over the coastal waters this afternoon. All Small Craft Advisories will be allowed to expire at noon. Tonight: Winds are forecast to veer from the NE this evening, remaining tonight between 10-15 kts. Seas are forecast to range between 3-5 ft tonight. Tuesday through Friday: Tuesday will feature moderate NE winds as high pressure continues to expand north of the region. The gradient will tighten late Tuesday night into Wednesday as an inverted trough develops well offshore. Seas will also continue to steadily build due to the persistent flow and long fetch. Small Craft Advisories will likely be needed beginning as early as late Tuesday night for all waters outside Charleston Harbor. We may actually need Gale headlines at some point Wednesday night into Thursday due to frequent 35 kt gusts. Otherwise, SCA conditions will continue all the way into next weekend as strong high pressure remains north of the waters. && .EQUIPMENT... KCLX remains operational, but level 2 data is not being distributed to external users due to an internal hardware failure. We are still awaiting the arrival of new parts to resolve this problem. Until then, level 2 data will not be available. Radar data is available for all connected AWIPS users. Level 3 data is also available for some external users. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$