Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
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400 FXUS62 KCHS 301751 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 1251 PM EST Sun Nov 30 2025 .SYNOPSIS... High pressure will prevail into Monday, and then a storm system will pass through the region late Monday into late Tuesday. High pressure then returns for the middle to end of this week ahead of the next frontal system that could impact the area Friday into the weekend. && .NEAR TERM /THROUGH TONIGHT/... Through Sunset: No hazardous weather is expected. Tonight: The mid-levels will consist of WSW flow overhead, with a trough passing well to our north. At the surface, a weak cold front will quickly move from west to east through our area this evening, shifting offshore overnight. High pressure will then build in from the northwest late. Even though PWATs will be ~1", the front will be in a weakening phase as it reaches our area, meaning any showers associated with it will be dissipating. The NBM struggles to give slight chance POPs to our far inland counties this evening, instead keeping a vast majority of our area rain-free. No QPF is forecasted. However, mid-level clouds will increase this evening and persist overnight. These clouds should keep low temperatures a few degrees above normal. Low temperatures should range from the mid 40s inland to the lower 50s along the immediate coast. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... On Monday, another cold air damming scenario unfolds as surface high pressure builds into the region from the north throughout the day, with the aforementioned cold front being pushed off to our south into northern Florida. This will drop afternoon temperatures back down into the mid 50s to mid 60s, warmest across southeast Georgia. Chances for rainfall remain low throughout the day (<20%), though mostly cloudy skies remain expected with breezy conditions, especially along the coast. Late Monday night, the primary upper trough axis moves over the eastern US as deepening surface low pressure over the deep south begins to ride up the Piedmont. Moisture advection over the still entrenched CAD will likely start widespread drizzle or very light rainfall around or shortly after midnight Monday night. A lingering source of uncertainty with this system is how quickly the CAD will erode as low level WAA increases through the morning hours Tuesday. Greatest precipitation rates will occur after the CAD erodes, with widespread moderate rainfall prevailing after sunrise Tuesday. Hourly rainfall rates will likely remain below 0.25 in/hr, with probs of any given location receiving greater than 1 inch of rainfall within a 6 hour window generally less than 20%. This, combined with very dry antecedent conditions, will keep the flooding threat very low - with the rainfall, which should total 0.5-1.5 in across the area, mainly just beneficial to combat the worsening drought. Chances for rainfall diminish Tuesday evening as the low departs, a cold front crosses the area, and subsidence develops aloft. Post-frontal CAA will be modest as high pressure builds in from the west on Wednesday, with temps 5-10 degrees below normal under mostly sunny skies. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... As the aforementioned surface high pressure moves offshore, temperatures will begin to nudge back to near normal, though likely remaining a few degrees shy in the mid 50s to lower 60s Thursday. An active pattern returns Friday through the weekend as a series of shortwaves cross the eastern US. Significant magnitude and timing uncertainty remains with any individual shortwave, but the overall expectation that a surface front will linger near the area, with periods of precip enhancement/waves within the front impacting the Southeast coast through much of next weekend. At this time, there is strong agreement within the large ensemble systems that any threat for wintry precipitation will remain north and west of our area. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... 18Z TAFs: VFR. A weak cold front will quickly move through our area this evening, bringing mid-level clouds. Extended Aviation Outlook: There are moderate probabilities (30-50%) for sub-VFR ceilings along the coast Monday as CAD develops. A storm system will bring higher probabilities (50-80%, lowest along the coast) of flight restrictions Monday night into Tuesday, with both low ceilings and lowered vsbys possible in addition to rain showers and isolated to scattered thunderstorms. && .MARINE... Through Sunset: No hazardous weather is expected. Tonight: A weak cold front will quickly move from west to east through the coastal waters this evening, shifting offshore overnight. High pressure will then build in from the northwest late. Expect light winds ahead of the front, becoming NNE sustained around 15 kt with gusts up to 20 kt just before daybreak Monday. Seas will average 3-4 ft. Monday through Thursday: A backdoor cold front will mode down the coast on Monday, bringing occasional 20-25 kt wind gusts midday through the afternoon. Coverage and duration too limited to justify SCAs given the marginal magnitude, but trends will need to continue to be monitored as SCAs possible across all coastal waters if the gradient tightens further. Seas mainly 3-5 ft Monday, though occasional 6 ft seas possible mainly beyond about 15 nm off the SC coast. Monday Overnight into Tuesday, a surface low pressure begins to move towards the region, traversing the area on Tuesday. This will bring the highest rainfall chances Tuesday morning, with both showers and isolated thunderstorms possible, decreasing into the evening hours. Winds becomes S as the CAD erodes very early Tuesday morning, with cooler waters limiting mixing in the WAA environment, but breezy conditions still likely. Seas do build and begin to approach/exceed 6 feet again on Tuesday. Thus, small craft advisories may be needed, especially in the offshore Georgia waters where seas approach 8 feet 60nm out. High pressure returns on Wednesday, with conditions improving and no marine hazards expected into the end of the week. && .TIDES/COASTAL FLOODING... Chances for minor coastal flooding return with the Tuesday early morning high tide, along the Charleston and Colleton county coast. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM... SHORT TERM...CEB LONG TERM...CEB AVIATION...CEB MARINE...CEB