000 FXUS62 KCHS 061119 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 619 AM EST Mon Feb 6 2023 .SYNOPSIS... High pressure will prevail through Wednesday. A series of cold fronts will affect the area late Thursday through Saturday morning, followed by dry high pressure. && .NEAR TERM /THROUGH TONIGHT/... For today: A strong short wave trough to the north will pass into the ocean early on, allowing for heights to rise locally as ridging builds from the west. At the surface we find intensifying low pressure about half way between Charleston and Bermuda at daybreak that is moving rapidly northeast. High pressure will build from the Ohio Valley with deep dry air settling into the local counties, so that once we get rid of the fog and stratus early on, a sunny day is on tap. A downslope flow through the boundary layer along with an expansion of the low level thickness and rising 850 mb temps will yield a warmer day than yesterday, with highs in the mid and upper 60s. Some locales south of I-16 in Georgia could hit 70 degrees. Temps this high will allow for a weak sea breeze to form along coastal Georgia in the afternoon, where the gradient is the lightest. Tonight: Ridging both surface and aloft will settle overhead, promoting a quiet but colder night. Winds will decouple with sunset, leading to excellent radiational cooling. While there will be some thin cirrus moving in, they won't have any bearing on low temps. Typically on nights such as this in winter the colder NAM and ECS MOS guidance provides the best snapshot of min temps. And then taking into account that even that guidance is often not cold enough, we are showing lows mainly in the mid and upper 30s near and inland from US-17. Lower and middle 40s will prevail along the barrier islands, in the Charleston and Savannah metro regions, and also along the shores of Lake Moultrie. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... A deep layered ridge will extend from the western Atlantic into the Southeast Tuesday through Thursday morning, then begin to shift east as an upper trough approaches. An upper shortwave will move into the area Thursday, accompanied by an increase in low-level moisture. A few showers could move in from the west Thursday afternoon. Otherwise, a steady warming trend is expected with above-normal highs pushing well into the 70s by Wednesday and Thursday. && .LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/... A series of shortwaves, followed by the arrival of a longwave trough and a cold front will bring scattered/numerous showers and a few thunderstorms to the area Thursday night through Friday night. Moisture and precip are expected to move off the coast by Saturday morning, with cool, dry high pressure building in. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... VFR through 12Z Tuesday at KCHS, KJZI and KSAV. NW winds around 10 kt and a little gusty today, before winds become light or calm with sunset this evening. Extended Aviation Outlook: Fog is possible late Tuesday night. Visibility and/or ceiling restrictions possible Thursday night and Friday as showers and thunderstorms move through. && .MARINE... Today: A 1027 mb high building out of Michigan and Ohio will prevail, resulting in NW to N winds as high as 15 or maybe 20 kt (a little less in Charleston Harbor), and seas no more than 3 or 4 feet with the offshore fetch. The gradient slackens enough this afternoon where a bit of a sea breeze will form near the Georgia coast. Tonight: the surface high will encompass the Southeast, leaving the local waters with mainly NE and E winds around 10 kt or less, while seas are just 2 or 3 feet. Tuesday through Friday night: Southerly flow will develop Tuesday and continue through late week as high pressure builds over the western Atlantic. Winds/seas expected to remain below advisory levels through Thursday night. Strengthening southerly flow ahead of a cold front Friday and Friday night is expected to result in 6 ft seas moving into the nearshore waters. Small Craft Advisories may be needed for most of the waters starting as early as Friday, continuing into Saturday. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...JRL LONG TERM...JRL AVIATION...JRL MARINE...