376 FXUS62 KCHS 050619 AFDCHSArea Forecast Discussion National Weather Service Charleston SC 219 AM EDT Sun Oct 5 2025
.SYNOPSIS... Strong high pressure will extend across the region through the weekend and into early next week. A strong cold front will likely cross the area later next week.
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.NEAR TERM /THROUGH TONIGHT/... Prior to Daybreak: Latest radar trends indicate scattered to numerous showers along with a few thunderstorms across coastal waters early this morning, associated with a weak coastal trough persisting offshore. This activity will make a run toward the coast within a easterly flow prior to sunrise, producing light to moderate shower activity across the coastal corridor and reductions to visibilities at times. Low temps should range in the mid 60s inland to lower 70s near the coast.
Today: Aloft, mid-upper lvl ridging will hold across much the Mid- Atlantic and Southeast while h5 vort energy shifts north across the Gulf and Deep South along its western edge. At the sfc, an inverted trough will linger offshore for much of the day along the southern periphery of high pressure extending from the western Atlantic into the Mid-Atlantic states, attempting to hold locally across the far interior and west of the region. Much like the previous morning, scattered to numerous coastal showers will be driven onshore within an easterly wind, producing light to moderate rains across the South Carolina and Georgia coastal corridor, before becoming more focused, but possibly with less coverage across coastal Georgia areas and the Georgia interior late morning into the afternoon. A breezy easterly wind is anticipated during the afternoon with an enhanced pressure gradient occurring between the coastal trough offshore and stronger high pressure inland and north. Wind gusts around 20-25 mph will be common, especially for coastal areas along and east of I-95. A fair amount of model consensus suggests a somewhat drier afternoon with activity more sparsely ongoing across Southeast Georgia, before the next wave of precip activity potentially drifts onshore again (including along the South Carolina coast) late afternoon/early evening. Prior to additional development, temps should warm into the low-mid 80s away from the immediate beaches.
Tonight: Little change to the pattern is expected during the overnight period in regards to a weak inverted trough persisting offshore and high pressure prevailing to the north and well inland. Expect conditions to be quite similar to the previous night, with the bulk of convection seen during daylight hours waning across land and becoming more focused across coastal waters by late evening and occurring through late night. An easterly wind will continue to nudge precip activity toward coastal areas late night, particularly approaching daybreak. For this reason, a slight chance of showers/thunderstorms remains in the forecast along much of the South Carolina and Georgia coast. Overnight lows could remain a degree or two warmer than the previous night, ranging in the mid- upper 60s inland to low-mid 70s near the coast.
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.SHORT TERM /MONDAY THROUGH WEDNESDAY/... Broad upper ridging persists Monday and Tuesday over the Southeast coast. At the surface, elongated high pressure to the north and west and persistent coastal troughing keeps the stream of subtropical moisture advection going, with mainly scattered showers continuing to push onshore during the day. Additionally rainfall amounts will be modest, with minimal impact from purely rainfall. However, with the threat for coastal flooding continuing, any rain that falls around the times of high tide could exacerbate flooding impacts for very low lying coastal areas.
Expect largely dry conditions to prevail Tuesday and Wednesday as the sfc ridge axis slides overhead, disrupting the stream of LL moisture. This will allow for a brief reprieve in breezy northeasterly winds as well, especially along the coast. Wednesday looks to be the warmest day of the week with some inland areas likely approaching 90.
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.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... H5 heights fall Thursday and Friday as a southern stream digs toward the Southeast. At the surface, strong high pressure building quickly over the Northeast will force a backdoor cold front down the eastern seaboard, likely crossing our area late Wednesday night or very early Thursday then pushing south and offshore. In terms of rainfall, overall low to mid level moisture remains fairly meager, which should keep accumulations on the lighter side with any coastal shower that occurs with FROPA.
Gusty NE winds return Thursday into Friday behind the front - 25th to 75th percentile reflecting a most likely wind speed along the coast of around 20-30 mph - to end the workweek, which, in addition to already elevated tide levels, could bring a period of very impactful tidal flooding to end the week. See coastal flooding section for more.
Later Friday through the weekend remains uncertain as additional shortwave energy could develop waves within the front offshore, bringing the potential for an unsettled period and continued windy conditions as ridging likely persists inland.
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.AVIATION /06Z SUNDAY THROUGH THURSDAY/... TEMPO MVFR/IFR conditions are possible with light to moderate showers impacting CHS/JZI/SAV terminals at various times between 06- 10Z Sunday, although TEMPO MVFR conditions could continue at SAV for an additional 2-3 hours mid morning. VFR conditions should then prevail at CHS/JZI/SAV terminals through 00Z Monday. However, brief MVFR restrictions are possible during a shower, mainly at SAV during afternoon hours. East-northeast winds are expected to become breezy at all terminals late Sunday morning through much of Sunday afternoon with gusts around 20 kt possible. MVFR cigs could then return at all terminals Sunday evening, between the 00-06Z Monday time frame, but confidence is too low to include in the most recent TAF issuance.
Extended Aviation Forecast: Lingering shower activity Monday brings a limited threat for brief restrictions at all terminals. Otherwise, no significant aviation impacts expected.
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.MARINE... Today and Tonight: High pressure will remain centered north of the region while an inverted trough remains offshore, leading to an east- northeast flow across local waters along with gusty showers and thunderstorms. A fairly tight pressure gradient will persist between these features, supporting wind gusts primarily in the 15-20 kt range, although a few gusts up to 25 kt can not be ruled out. Seas will also remain elevated, generally between 4-6 ft nearshore and 6- 8 ft across outer Georgia waters. Small Craft Advisories will therefore remain in place for all local waters outside the Charleston Harbor today and tonight.
Sunday Onward: Very long fetch easterly winds will bring persistent medium period swell across the waters, with some underlying, but much smaller, longer period swell through early week as well. The swell will peak Monday with wave heights reaching 6-9 ft offshore, before only gradually subsiding through midweek, when breezy NE winds will begin to ease as well.
Rip Currents: A high risk of rip currents will continue through Monday in primarily medium period E to NE swells.
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.TIDES/COASTAL FLOODING... Early morning: Latest tide observations and guidance support minor/moderate coastal flooding for Charleston and Coastal Colleton and potentially up to minor coastal flooding from Beaufort County, SC south to McIntosh County, GA with the upcoming high tide cycle this morning. A Coastal Flood Advisory has been issued for Charleston and Coastal Colleton County as a result for the upcoming high tide cycle, ~6:46 AM at Charleston Harbor, SC. A Coastal Flood Advisory could eventually be needed across southern South Carolina and Southeast Georgia.
Astronomical tides will continue to increased through next week due to the upcoming full moon (Oct 7) and perigee (Oct 8). Additionally, tidal departure values will remain elevate with periods of breezy NE winds this weekend through Monday, then again Thursday into next weekend. As a result, the threat for mainly minor to moderate coastal flooding with each high tide cycles continues through mid- week. Then, late week, the threat for major coastal flooding arrives with the late morning high tides.
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.CHS WATCHES/WARNINGS/ADVISORIES... GA...High Risk for Rip Currents through this evening for GAZ117-119-139- 141. SC...High Risk for Rip Currents through this evening for SCZ048>051. Coastal Flood Advisory until 9 AM EDT this morning for SCZ049- 050. MARINE...Small Craft Advisory until 2 PM EDT Tuesday for AMZ350-352-354. Small Craft Advisory until 6 AM EDT Wednesday for AMZ374.
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NEAR TERM...DPB SHORT TERM...CEB LONG TERM...CEB AVIATION...CEB/DPB MARINE...CEB/DPB
NWS CHS Office Area Forecast Discussion