Area Forecast Discussion
Issued by NWS Charleston, SC

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000 FXUS62 KCHS 100158 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 958 PM EDT Fri Jun 9 2023 .SYNOPSIS... High pressure will build into the region tonight into Saturday. A front will lift northward through our region on Sunday, followed by a cold front advancing into the region Monday into Tuesday. The front could linger across the region into the middle of next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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While does show a stray shower south of the Altamaha River and east of the waters in the Gulf Stream, no rainfall is expected through the night over the local counties. Winds have gone light or calm in many places, setting the stage for a cool night for June standards, down into the upper 50s and lower 60s inland, with mid and upper 60s closer to the coast. A few places across Berkeley, Dorchester and Colleton County could dip into the mid 50s. There is still not enough evidence for fog to be included in the forecast. But we will continue to monitor. Previous discussion... Any isolated showers will end by sunset, and the night will be controlled by high pressure near the spine of the Appalachians, as the cold front is to the south of the region. Winds will quickly decouple this evening, and under clear or mostly clear skies and the dry air mass, we`re looking at an unusually cool June night. We lowered most temps by about 1-2F degrees, and might have to adjust further pending later trends. There remain indications of some late night fog and also low stratus, and we might need to consider adding it to the forecast at a later time. The sky remains smoky/hazy from the Canadian wildfires, and it`s interesting that the local air quality is now actually worse than New York City according to the fire.airnow,gov website. Any reduction in surface visibilities remains too low to mention in the actual forecast.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... Pattern Synopsis/Forecast: W-E oriented stalled boundary stretches through the Gulf Coast states/southern Georgia and into the Atlantic with surface high pressure to our north. Boundary will remain more or less stalled heading into the weekend before advancing back northward through our area late in the weekend into early next week. Meanwhile, larger scale ridging remains prominent across the western CONUS with downstream troughing across the northeast and down through the east coast. This pseudo blocking pattern will remain in place through the weekend and into early next week while another piece of strong short-wave energy dives out of Canada and carves out a deep closed low across the Great Lakes and Ohio Valley. Deepening upper level low will eventually help push a cold front into our area early next week. Details: Saturday still looks to be the quietest day of the upcoming weekend with slightly drier air and surface high pressure across the region, and the boundary still stalled south of our area. Only caveat will be down across far SE Georgia where some showers could again kick off in the vicinity of the boundary and aided by the sea breeze. However, with the drier air, precip chances are too low to add to the forecast at this juncture. Sunday and Monday will turn a bit more active. Upper level flow across the southeast CONUS will become a bit more cyclonically amplified as aforementioned short-wave energy carves out a deep closed low over the Great Lakes and Ohio Valley. Increasing southwesterly flow will finally draw the stalled boundary northward up through our region on Sunday with showers and some thunderstorms expected to develop along the advancing boundary and impacting the region. Surface cold front will follow heading into early next week, pressing into the southeast region on Monday and potentially through our area early Tuesday. This will bring another period of increased rain chances on Monday...and potentially some stronger thunderstorms as well. Will need to keep an eye on that as we go through the weekend. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Larger scale troughiness will remain the dominant player through the balance of week as the closed upper low pinwheels through the Great Lakes region. Surface cold front from Monday could slow/stall along or just off our coast and down through the Gulf Coast states and may set the stage for additional rounds of showers and thunderstorms to impact the region through the week. But, lots of differences among the long term guidance regarding how that all unfolds. We have periodic chances for showers/storms through the week, although details in timing/placement will need adjusting as we go along. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... VFR is forecast at all sites through 00Z Sunday. However, there is a risk for at least temporary flight restrictions in fog and/or low stratus from about 08Z to 13Z, especially at KSAV. Probabilities are not yet high enough to include with the latest TAF set. Extended Aviation Outlook: VFR conditions will prevail at the CHS/JZI/SAV terminals during the period. However, brief flight restrictions are possible due to afternoon showers and or thunderstorms through Wednesday. && .MARINE...
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Overnight: Continental high pressure will build into the area as a stationary front drifts further south and away from the forecast area. With the building high pressure winds that are 10 or 15 kt early on will diminish to 5 or 10 kt overnight. Seas will be around 2 feet or less. Extended Marine: High pressure will build across the local waters this weekend leading to northeast winds around 10 kt and seas between 1-2 ft on Saturday. A warm front will then advance northward through the region on Sunday veering winds into the south and eventually southwest on Monday. Winds on Monday will become a bit gusty, with some gusts potentially touching Small Craft Advisory criteria Monday afternoon and Monday night, particularly across the Charleston nearshore waters and the Georgia outer waters. Seas are looking to remain below 6 feet however. Winds and seas will back off some for the balance of the day.
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&& .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...Adam LONG TERM...Adam AVIATION... MARINE... is the U.S. government's official web portal to all federal, state and local government web resources and services.