Area Forecast Discussion
Issued by NWS Charleston, SC
Issued by NWS Charleston, SC
105 FXUS62 KCHS 171112 AFDCHS Area Forecast Discussion National Weather Service Charleston SC 712 AM EDT Thu Jul 17 2025 .SYNOPSIS... Atlantic high pressure will prevail through the weekend. A cold front may sag into the area early next week. && .NEAR TERM /THROUGH TONIGHT/... Today: Aloft, the ridge centered across the western Atlantic will stretch further back to the west and extend inland across GA and the Carolinas, all the way to the Southern Plains. At the surface, a classic summertime setup with the subtropical high solidly in control driving generally southerly flow across the area. Model consensus is good, favoring very little diurnal convection across the area. Soundings feature very warm profiles, weak lapse rates, and MLCAPE values struggling to reach 1,000 J/kg. All this, with the influence of the ridge aloft should result is very little coverage this afternoon. There are some DCAPE values of 1,000 J/kg or higher, so if a storm can get going there could be a gusty wind threat. But overall, the expectation is for nothing more than isolated coverage likely not until the mid to late afternoon. Another consequence of the ridge aloft will be warming temperatures. Highs are expected to reach the low to mid 90s for the area away from the immediate coast. These temperatures combined with dewpoints in the low to mid 70s should yield heat index values mostly in the 100-105 degree range. Tonight: If there are any showers or storms lingering from the afternoon, they will dissipate quickly with the loss of diurnal heating. The rest of the overnight should be quiet with lows in the mid to upper 70s. && .SHORT TERM /FRIDAY THROUGH SUNDAY/... A deep layered ridge will prevail through the weekend, maintaining fairly typical conditions for summer in the South. Temperatures will slowly climb through the period, with highs reaching the mid to upper 90s in most areas away from the coast on Sunday. Heat indices could top 108 degrees in parts of the area Saturday and Sunday, so we may end up needing Heat Advisories. Fairly strong mid-level subsidence will limit the convection potential so we are carrying 20-30% PoPs. && .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/... A more active pattern is on tap for early to mid next week as the upper ridge axis shifts west and a series of shortwaves rotates into the area from the north. Additionally, a weak surface front is progged to sag into the area Monday afternoon, then linger in the area. && .AVIATION /11Z THURSDAY THROUGH MONDAY/... The 12z TAF period begins with VFR conditions at KCHS, KJZI, and KSAV. There is some isolated to scattered morning shower activity that could impact primarily KCHS and KJZI through mid morning. This shower activity should dissipate by mid to late morning. Very little thunderstorm activity is expected this afternoon so we have no mention of anything at the terminals. Southerly flow will become breezy this afternoon, with gusts into the 15-20 knot range possible. Extended Aviation Outlook: VFR will mainly prevail throughout the period, however brief flight restrictions are possible within showers and thunderstorms that develop in the afternoon and/or evening hours. && .MARINE... Today and tonight: The subtropical high will be the primary feature through the period and will continue to drive elevated south to southwest flow. Wind speeds will top out in the 15-20 knot range at times, especially along the land/sea interface this afternoon and through the evening. Seas should average around 3 feet through the period. Isolated to scattered showers and thunderstorms could impact portions of the waters early this morning, but for the most part conditions should be quiet. Typical summertime weather pattern with moderate southerly flow will prevail Friday through Monday. Headlines not expected. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...BSH SHORT TERM...JRL LONG TERM...JRL AVIATION...BSH/JRL MARINE...BSH/JRL