Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
440 FXUS62 KGSP 161050 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 650 AM EDT Wed Jul 16 2025 .SYNOPSIS... Daily thunderstorm chances continue through the week and into the weekend. A few storms could produce damaging wind gusts and localized flash flooding. Hot and humid conditions stick around through most of the forecast period. && .NEAR TERM /THROUGH TONIGHT/... As of 645 AM Wed: Southerly flow regime continues across the CWA. Despite rather poor lapse rates owing to the deep subtropical moisture over the area, and after a lull in the late overnight hours, convection recently redeveloped along the south facing slopes of the Blue Ridge Escarpment where terrain is enhancing lift. Parts of Transylvania County saw 1-2" accumulation overnight and rates will need to be monitored with the new activity. Low LCLs may allow some continued redevelopment or propagation northward over the next couple of hours. Otherwise, today looks to be closer to a typical midsummer setup for the Carolinas/Georgia as moist southerly flow continues, with PWATs remaining in the 1.8 to 2 inch range. Influence of low pressure near the FL Panhandle should diminish, with flow remaining southerly as opposed to southeasterly as yesterday; the Bermuda High dominates, and coverage appears lesser overall. Modest instability is re-established by midday and ridgetop initiation appears possible again by early afternoon, supporting near-climo PoPs, mostly 40-50%. A weak capping layer persists in prog soundings over much of the Piedmont which will keep initiation isolated there, but models mostly feature better coverage in the slightly more favorable environment in the CSRA and Midlands to our south which could propagate north, so low chance PoPs are retained for our southeastern zones. Max temps near normal with higher than typical dewpoints as a result of the subtropical moisture and limited mixing, so some areas may exceed 100 heat index. Some CAMs, and seemingly the NAM, depict evening convection propagating into our southern zones along sea breeze, or an outflow boundary from South Georgia. Similar to this morning, a nocturnal inversion appears slow to form and such activity can`t be ruled out, nor can a few isolated cells developing on south-facing slopes, so we retain small PoPs much of the night, slowly diminishing by early Thu morning. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... As of 125 AM EDT Wednesday: Bermuda ridge will gradually expand westward during the period, while steady west to southwesterly flow filters in continuous hot and humid conditions. A slight uptick in temperatures and heat index values are evident with muggy dewpoints and warmer thicknesses in place. Diurnal convection will continue through the end of the workweek, especially in the mountains where above climo PoPs are expected. Trends in PWAT values have lowered, likely being choked off by the tropical disturbance over the Gulf. This helps to lower the overall hydro threat, but there will still be the concern of a few instances of localized flash flooding to go along with the wet microburst threat. Temperatures will continue to run a category or so above normal, with heat indices in the low 100s across the Piedmont Thursday and Friday and only flirting with Advisory criteria by Friday. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 145 AM EDT Wednesday: The aforementioned extension of the Bermuda ridge will set up shop over the southeastern CONUS by this weekend into early next week. Ambient temperatures are likely to be a few ticks higher compared to the short term for this weekend into early next week as a result. Dewpoints remain elevated as well, which could combine for a better chance for Advisory criteria heat indices, especially in the Charlotte metro and Lower Piedmont. As the ridge continues its westward push further into the Deep South and Lower Mississippi Valley early next week, the flow aloft flattens out a bit and turns more west to northwesterly and places a somewhat favorably track for MCSs to push further south into the CFWA. This will be a trend to keep an eye on, but either way the day to day pulse convection and localized flash flood threat will be in play each day in mid-July fashion unless interrupted by said MCS potential. The forecast mostly remains the same each day through D7 (wash, rinse, repeat). && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... At KCLT and elsewhere: Terrain-induced showers SW of KAVL at issuance time; this is handled with a TEMPO at the start of the period. Transient low MVFR cumulus are seen around the rest of the area and included a TEMPO at those sites for possibility of a cig. Low LCLs should result in FEW-SCT cu remaining at MVFR level through mid to late morning, with bases then lifting to VFR. Winds remain S to SSW today. Fairly typical, mainly afternoon and early evening PROB30s for TSRA at all sites. Convective debris or patchy low VFR stratocu likely will be floating around the terminal area tonight; restrictions most likely along the Blue Ridge Escarpment near KAVL and perhaps in areas where heavy rain falls in the evening. Depictions of stratus creeping in from the coast proved overdone this morning so not buying those models showing it for Thu morning. Outlook: Thunderstorm chances each afternoon/evening. Low stratus or fog are possible each morning in mountain/river valleys. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CAC NEAR TERM...Wimberley SHORT TERM...CAC LONG TERM...CAC AVIATION...Wimberley