843 FXUS62 KCHS 010140 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 840 PM EST Sat Feb 28 2026 ...AREAS OF DENSE FOG POSSIBLE SUNDAY MORNING... .WHAT HAS CHANGED... A dense fog key message was added for tonight/Sunday morning. The aviation section was added to address the 29/00z TAFs. && .KEY MESSAGES... - 1) Areas of low clouds and fog again tonight. Dense Fog possible. - 2) Notable temperature swings through Wednesday. - 3) Warm temperatures and chances of rain for late next week into the weekend. && .DISCUSSION... KEY MESSAGE 1: Areas of low clouds and fog again tonight. Dense Fog possible. Incoming guidance is trending foggier overnight as clouds steadily thin out. Clouds will linger the longest over the Charleston Tri-County (especially Charleston County), but this where signs are indicating more of a stratus build-down fog event versus a radiational fog event elsewhere across the forecast area. The mention of dense fog was expanded a bit farther to the east and a Dense Fog Advisory could be needed overnight. Conditions will favor the development of a mixture of radiational fog and fog resulting from stratus build-down overnight. The lowest 1000 hPa condensation pressure deficits are progged to occur roughly along/west of I-95. While most of the guidance is trending towards a foggier solution overnight, there are still a few stubborn members who suggest fog will not be much of a concern overnight. Given light winds, lingering stratus and favorable condensation pressure deficits, the foggier solutions seem more probable at this time. Motorists are urged to slow down and leave extra distance ahead of you in case a sudden stop is needed whenever fog is encountered. KEY MESSAGE 2: Notable temperature swings through Wednesday. The mid-levels will consist of troughing over the East Coast this evening. It'll gradually transition to zonal flow by late Monday, followed by ridging building over the Southeast U.S. Tuesday into Wednesday. At the surface, High pressure will prevail through Sunday. A dry cold front will move south through our area Sunday night, followed by High pressure passing to our north on Monday. This will cause quite a swing in temperatures. Following lows near normal in the 40s tonight, temperatures will rise well above normal on Sunday, into the mid 70s for most locations (except cooler at the beaches), then remaining a few degrees above normal Sunday night. The wedge pattern will lead to a drastic temperatures gradient on Tuesday. Highs will range from the lower to middle 50s near the Santee River, rising to the lower to middle 70s near the Altamaha River. But given this synoptic setup, there is a high probability for high temperatures to be drastically different for any particular spot on Monday. Though, low temperatures on Monday night should be within a few degrees of normal. High temperatures rise back above normal on Tuesday, ranging from the lower to middle 70s away from the beaches. The warming trend continue on Wednesday with highs ranging from the mid to upper 70s across most of our area (except cooler at the beaches), and possibly the lower 80s across portions of inland GA south of I-16. KEY MESSAGE 3: Warm temperatures and chances of rain for late next week into the weekend. The region will be under the influence of high pressure, both at the surface and aloft, centered offshore late next week into the weekend. This will set the stage for warming temperatures. There is a fairly small spread in max temperature guidance, with upper 70s to even low 80s likely in most locations away from the immediate coast. Early March normals are in the upper 60s, so these values would be around 10 degrees above normal. Lows will also trend on the more mild side, in the upper 50s to around 60. Deeper moisture will return to the area with ensemble means indicating PWats climbing to around 1.1", which falls in the 85-90th percentile of climo. While larger scale forcing is lacking, moisture and some instability could lead to isolated to scattered diurnally driven showers developing, especially in the afternoons and into the early evening. NBM indicates only a 10-20% chance for >0.25" of rain in any 24 hour period during this time frame. Severe and flooding risk looks minimal at this time. && .AVIATION /01Z SUNDAY THROUGH THURSDAY/... 29/00Z TAF Discussion: KCHS/KJZI: Low stratus with IFR cigs has been slow to clear today. These cigs will likely linger through mid-evening before scouring out. Some shallow ground fog could develop prior to daybreak with brief periods of MVFR vsbys possible. Condensation pressure deficits are high, so dense fog is not expected at this time. There may be a brief period of LIFR cigs just before daybreak, so confidence on this is low. VFR will return shortly after daybreak Sunday and linger through the remainder of the 00z TAF period. KSAV: Clouds will scatter out this evening. Conditions looks favorable for fog to develop overnight, especially after 06z. Near term guidance is trending pretty foggy and the 00z TAF was trended in that direction. Expect prevailing 2SM in BR by 08z with vsbys dropping as low as 1/2SM at times 10-13z. There is about ~40% chance that prevailing vsbys will drop to 1/2SM or lower after 10z, so amendments may become necessary as trends become more apparent. The fog/low clouds should mix out a few hours after daybreak with VFR conditions prevailing there after. Extended Aviation Outlook: VFR. && .MARINE... Dense fog may make a run for the Charleston Harbor early Sunday and a Marine Dense Fog Advisory may eventually be needed. High pressure will prevail through the weekend. A dry cold front will move south through the waters Sunday night, followed by High pressure passing to our north on Monday. This will cause a surge in northwest winds. Small Craft Advisories will be needed for all of the ocean zones from Monday into Monday night. Models continue to hint at wind gusts approaching 35 kt across the Charleston waters, so a Gale Watch may eventually be needed. Winds trend lower late Monday night into Tuesday, though seas will be slower to subside. Advisories would expire for the waters within 20 nm first, and then the GA waters beyond 20 nm, possibly not until Wednesday. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$