FXUS62 KCHS 280510 AFDCHS
Area Forecast Discussion National Weather Service Charleston SC 1210 AM EST Fri Nov 28 2025
.SYNOPSIS...
High pressure will prevail through the weekend. A low pressure system could impact the area early next week.
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.NEAR TERM /THROUGH TONIGHT/...
Today: The base of the longwave East Coast trough will swing by to the north early this morning with mid-level heights progged to slowly rise through the day and into tonight. The flow will transition to a more zonal-type configuration through the period with Canadian high pressure expected to build into the Central Appalachians by daybreak Saturday. Cool and very dry conditions will persist as a modified continental polar (cP) airmass maintains its influence on the region. Cold 850 hPa temperatures of +1 to -2C will keep daytime temperatures rather chilly, but ongoing downslope trajectories off the Southern Appalachians will help boost highs a bit compared to what full insolation low-level thickness schemes would suggest. Highs look to peak in the lower-mid 50s with lower-mid 50s at the beaches which is about 10-15 degrees below normal for late November.
Tonight: High pressure will persist through tonight. High clouds associated with both the polar and subtropical jets will spread east across the area overnight. Although the boundary layer could decouple this evening, especially inland, influences from the increasing cloud canopy will likely curtail the degree of radiational cooling. The pressure gradient will also begin to tighten late as the position of the high to the north begins to initiate the development of a coastal trough just offshore. It will still be rather chilly with lows expected to drop into the upper 20s inland to the mid-upper 40s at the beaches. As winds begin to nudge higher closer to daybreak, wind chill values could drop into the mid 20s inland with mid 30s at the beaches. This is just above Cold Weather Advisory criteria.
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.SHORT TERM /SATURDAY THROUGH MONDAY/...
Surface high pressure north of the area will keep conditions cool and dry throughout the day, with high temperatures a touch warmer in the upper 40s to upper 50s, possible lower 60s across far southeastern Georgia. Overnight into Sunday, lows are again expected to dip into the mid 30s far inland to the mid/upper 40s along the coast. Per the ensemble situational awareness tables, these temperatures are in the bottom 10th percentile of climatology, thus not expecting any records to be broken. As a weak stationary front develops off the southeast Georgia coast by the evening hours, may see some weak and light showers develop near/onshore, but for now the NBM keeps the forecast dry on land.
For Sunday, the aforementioned stationary front mixes out as onshore flow returns ahead of an approaching cold front. 850mb temperatures reach back up into the upper single digits expect, so expecting a much warmer day with highs back up into the mid to upper 60s across southeastern South Carolina and upper 60s to mid 70s across southeastern Georgia. Isentropic lift may again result in some weak showers developing during the afternoon hours, but the better chances arrive during the evening as the cold front slips through the area along with some scattered and weak shortwaves.
Surface high pressure builds into the region from the north throughout the day on Monday, with the previous front being pushed off to our south across northern Florida. This will drop afternoon temperatures back down into the mid 50s to mid 60s, warmest across southeast Georgia. With isentropic lift continuing aloft and scattered shortwaves out ahead of an approaching trough moving across the area, low chances (20-30%) for scattered showers continue throughout the day.
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.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
As the aforementioned trough continues to move towards the area, a surface low will be moving towards the area across the Gulf which will be increasing rainfall chances into Tuesday. Timing of the heaviest rainfall is a little uncertain, but currently looks most likely during the daytime hours on Tuesday as the surface low traverses the region. Despite precipitable water values approaching the 90th percentile of climatology near 1.5 inches, rainfall amounts look to remain in the 0.5-1.0 inch range, highest across southeast South Carolina.
Chances for rainfall dwindle into the overnight hours, with surface high pressure building into the region behind the cold front. With strong zonal flow aloft, the surface high pressure moves offshore fairly quickly, bringing temperatures back to near normal.
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.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
28/06z TAF Discussion: KCHS/KJZI/KSAV: VFR through 29/06z.
Extended Aviation Outlook: VFR conditions are expected through Saturday. Flight restrictions are possible at all terminals due to showers and low clouds associated with a passing front Sunday afternoon/evening, remaining possible through Tuesday.
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.MARINE...
Through Daybreak: A modest northwest to north wind surge will persist across the waters through daybreak. The strongest 1000-850 hPa winds are directed into the Georgia waters which should support winds of 20-25 kt with gusts near 30 kt. Over the South Carolina waters, winds should average closer to 15-20 kt but gusts could approach 25 kt at times. A Small Craft Advisory remains in effect for the Georgia nearshore and offshore zones through 7 AM.
Through Tonight: North winds will gradually diminish across the waters today then veer to the northeast tonight as high pressure moves into the Central Appalachians. Speeds will settle into the 10-15 kt range this afternoon and evening, then begin to increase back into the 15-20 kt range early Saturday in response to a tightening pressure gradient and the development of a weak coastal trough offshore. Seas will subside to 2-4 ft this afternoon and persist into the overnight hours.
Saturday through Tuesday: Surface high pressure to the north will keep the surface pressure gradient elevated throughout Saturday, resulting in semi-breezy northeasterly winds. Winds look to remain below advisory criteria at near 20 knots, but something to keep an eye on. May see some weak showers or even an isolated thunderstorm develop by the afternoon especially well offshore (40+nm out), with chances for periodic rainfall continuing throughout the day on Sunday. Winds weaken on Sunday, but will be increasing throughout the day on Monday as a cold front approaches the area from the west with rainfall chances similarly increasing throughout the day. A surface low pressure is expected to traverse the region on Tuesday, continuing chances for showers and some thunderstorms, with winds remaining elevated. Winds currently look sub-advisory, but seas do begin to approach/exceed 6 feet on Tuesday.
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.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None. SC...None. MARINE...Small Craft Advisory until 7 AM EST this morning for AMZ354-
374.
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