724 FXUS62 KCHS 111755 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 155 PM EDT Wed Jun 11 2025 .SYNOPSIS... A series of upper level disturbances will affect the area through the weekend while high pressure remains offshore. && .NEAR TERM /THROUGH TONIGHT/... Rest of This Afternoon: Ridging aloft will build into the southeastern states from the east, putting the forecast area along the western periphery of the anti-cyclonic flow. At the surface, WPC has analyzed a stationary front positioned over the SC Midlands, with weak high pressure extending over the local forecast area. Radar imagery as of 2 PM shows showers and thunderstorms developing over the SC Midlands. Coverage of showers and storms is expected to increase this afternoon, mainly driven by outflow boundary interactions as well as the inland progressing sea breeze. Both low- and mid-level flow is very weak this afternoon, with the 12Z KCHS RAOB sounding showing generally 10 to 15 knots. Therefore, storms will be slow moving, if they move at all. The main threat posed by the afternoon thunderstorms will be localized heavy rainfall, although a strong to marginally severe wind gust cannot be completely ruled out. HiRES models remain in slight disagreement, with the 12Z HREF showing the most coverage. Recent runs of the HRRR as well as the 12Z FV3 show minimal coverage. Given that convection has already initiated further inland, the forecast features PoPs generally in the 40-50% range this afternoon. High temperatures today have reached into the upper 80s across the region. Tonight: Lingering afternoon convection should gradually diminish through the evening and then pick up in coverage across the coastal waters through the late night hours. Lows are forecast to fall into the low 70s. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... A relatively warm and moist airmass will persist through Saturday with the area on the western side of an upper ridge just off the FL coast. A series of shortwaves will ripple across the area during this time, maintaining some upper forcing for convective development. With highs in the upper 80s and dewpoints solidly in the 70s, daytime CAPEs should reach 1000-1500 J/kg which will support numerous showers and tstms to develop, particularly in the afternoon/evenings. The severe thunderstorm potential looks fairly low. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... An upper ridge over the western Atlantic will slowly expand west over the weekend into early next week. Diurnal convective coverage will gradually decrease through the period as mid-level subsidence strengthens. Highs will creep upward each day, with readings in the low to mid 90s by early next week. Given surface dewpoints in the mid to upper 70s, heat indices could reach 108 degrees in a few spots, especially in the sea breeze corridor. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... The 18Z TAF period will initialize with VFR conditions at all terminals (KCHS/KJZI/KSAV). Showers and thunderstorms could impact the terminals this afternoon, however given the pop-up nature of the storms direct impacts to the terminals remains a very low confidence forecast. The 18Z TAFs feature VCTS from 20 to 22Z at KCHS and KJZI and 21 to 00Z at KSAV. Some models are hinting at fog formation tonight, especially over areas that see rainfall this afternoon. As of this juncture the best chances for fog look to remain inland of the terminals and there is no mention of fog or restrictions in the 18Z TAFs. Extended Aviation Forecast: Brief flight restrictions are possible in showers and thunderstorms each day, mainly in the afternoon. && .MARINE... Tonight: Winds are expected to be more southerly today with speeds mostly topping out in the 10-15 knot range early this evening. Overnight winds will diminish slightly overnight, generally around 10 knots. Seas should mostly average 2-3 feet through the period. Thursday through Tuesday: Marine conditions are expected to stay below Small Craft Advisory criteria through the period. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...CPM SHORT TERM...JRL LONG TERM...JRL AVIATION...CPM/JRL MARINE...CPM/JRL