Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
202 FXUS62 KCHS 111821 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 221 PM EDT Mon Aug 11 2025 .SYNOPSIS... A hot and humid air mass will build over the region through mid-week, then will likely linger through this weekend. && .NEAR TERM /THROUGH TONIGHT/... Current - This Afternoon: Dreary conditions continue to prevail across the region, as a band of heavy rainfall lifts northeast of Charleston, with a secondary band now northeast of Savannah. PWATs still remain elevated during this time, with values between 2 to 2.5 inches. In terms of impacts, this resulted in a decent amount of flooding and flash flooding in urban/low-lying areas - which prompted numerous road closures and a few car rescues. While the initial band this morning may have been a bit more robust than the secondary band forming, still want to emphasize that heavy rainfall and flooding still remain possible this afternoon and evening. In regard to totals, could easily see another 1 to 2 inches, with isolated pockets of 3+ inches - thus, the Flood Watch will remain in effect until 6 PM. One last thing of note - while severe weather is not expected at this time, think it`s worth mentioning that tree damage can still occur despite the lack of severe level gusts (58+ MPH), given the saturated soils in place. Have already noted a few downed trees this morning, with gusts only reaching 30 to 35 MPH. Tonight: Should see any lingering convection/rainfall quickly diminish throughout the overnight period, as lows fall into the lower 70s inland to the upper 70s along the coast. Otherwise, latest CAMs continue to hint that convection may redevelop offshore prior to daybreak, with coverage likely to be more isolated/scattered. && .SHORT TERM /TUESDAY THROUGH THURSDAY/... Tuesday, the forecast area will remain between high pressure over the western Atlantic a broad low pressure over the lower Mississippi River Valley. This pattern should support steady SSE winds across the CWA. High resolution guidance indicates that as temperatures reach the upper 80s to low 90s across the region, a sea breeze will develop during the early afternoon hours. Forecast soundings indicate that CAPE is forecast to range from 1500-2000 J/kg. Scattered to numerous showers and thunderstorms may develop along the sea breeze, tracking inland between 10 to 20 mph. Given dewpoints in the mid to upper 70s, heat index values should peak between 100-106 degrees. Wednesday and Thursday, the center of a 595 dm ridge will build over FL and the eastern Gulf. High temperatures are forecast range in the low to mid 90s. Forecast soundings indicate a weak subsidence inversion around H7 should be overcome during the heat of the afternoon, yielding scattered convection along the sea breeze. In addition, heat index around 105 degrees should be common each afternoon. It is possible that conditions could reach Heat Advisory levels across coastal GA both days. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Friday into early next week, H5 ridge will shift over the Deep South. GFS indicates that a shortwave could ripple across forecast area early next week. This pattern should yield a typical summer- time pattern with afternoon thunderstorms and hot and humid conditions. Heat index values may peak at or near Heat Advisory criteria across coastal GA and the lower SC coast on Friday. && .AVIATION /19Z MONDAY THROUGH SATURDAY/... 11/18Z TAF Discussion: Unsettled weather continues across the region, as a second band of precipitation near KSAV lift northeastward into South Carolina. Similar to this morning, should see largely VFR conditions prevail, with IFR to MVFR levels possible during periods of rain. Have continued to highlight this using TEMPO groups. Otherwise, could see some low stratus creep into our interior counties prior to daybreak, which may result in a brief period of MVFR cigs. Have opted to forgo any mention of this for the time being given the lack of confidence, but will continue to monitor trends in the coming shifts and add as necessary. Extended Aviation Forecast: Brief flight restrictions will be possible due to afternoon showers/thunderstorms. && .MARINE... Through Tonight: No concerns. East/southeast winds 15 kt or less will prevail with seas 2-4 ft. Tuesday through Saturday: The pattern should generally support south winds between 10 to 15 kts with seas between 2 to 3 ft. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...Flood Watch until 6 PM EDT this evening for GAZ116>119-138>141. SC...Flood Watch until 6 PM EDT this evening for SCZ048>051. MARINE...None. && $$ NEAR TERM...SST SHORT TERM...NED LONG TERM...NED AVIATION...NED/SST MARINE...NED/SST