Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
311 FXUS62 KCAE 080941 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 541 AM EDT Tue Jul 8 2025 .SYNOPSIS... Temperatures remain above normal today and tomorrow with diurnally driven showers and thunderstorms. Some decrease in high temperatures is possible later in the week as weak upper troughing moves in from the west while rain chances increase slightly. && .NEAR TERM /THROUGH TONIGHT/... Key Message(s): - Hot with scattered thunderstorms expected this afternoon across the area, with some isolated damaging winds possible. Very hot and unsettled conditions expected for Tuesday afternoon as above average heights and ridging aloft remains in place. A weak thermal lee of the Appalachians surface trough will linger across the Upstate of SC this afternoon and the boundary of this will likely act as the trigger for convection in the afternoon; HREF instability fields depict a notable CAPE gradient across the Midlands by 18z. This trough is evident in the overnight moisture presence, with dew points in the mid-upper 60`s in the Upstate and in the mid-70`s here in the Midlands. So as temps climb into the upper 90`s, some weak mesoscale lift will develop along the eastern flank of this trough-moisture gradient. Instability even across the Midlands will be somewhat limited due to poor mid-level lapse rates, around 1250-1750 or so J/kg of ML CAPE, but coverage should be fairly widespread given the bit of enhanced mesoscale forcing. DCAPE will be pretty high with a deep inverted V, surface temps near 100 F, and decently widespread convective coverage, so some isolated strong to damaging wind gusts are possible in spots this afternoon and evening. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... Key Message(s): - Not as hot on Wednesday and Thursday. - Shower and thunderstorm chances increase. A few thunderstorms may become strong with damaging winds as the primary severe hazard. - High PWATs through the period, combined with weak steering flow, suggest a flash flood potential with any convection. Upper trough centered in the Great Lakes region at the start of the period slowly shifts eastward and will have an increasing influence on our weather during the short term. The first impact will be lower temperatures due to the increased cloud cover across the FA with near normal daytime temperatures favored on Wednesday and especially Thursday. The approaching trough could aid in increasing convective development across the CWA with CAMs showing development focused in the Upstate on Wednesday heading eastward in the afternoon and evening. Given the overall lack of a strong trigger, pulse thunderstorms are favored and could also form through colliding mesoscale boundaries and the sea breeze front moving inland. Inverted-V modeled soundings would suggest that damaging downburst winds will be the primary severe hazard though this threat will likely be localized in nature due to the pulse environment. The Day 2 (Wednesday) and Day 3 (Thursday) SPC SWO places the entire CWA in a Marginal (1/5) risk, which is reasonable given these parameters. Conditions are similar on Thursday though increased cloud cover could limit instability. Southwesterly flow ahead of the upper trough will continue to transport high levels of atmospheric moisture into the region, with PWATs expected to be in the 2 to 2.25 inch range on Wednesday and slightly lower on Thursday. The Day 2 WPC ERO places the entire FA in at least a Marginal (1/4) risk with a Slight (2/4) near the North Carolina border. The Day 3 ERO limits the Marginal risk to the northern half of the CWA. The high moisture and weak steering flow in addition to long skinny CAPE profiles in modeled soundings favor a flash flood threat from any thunderstorms that develop. && .LONG TERM /FRIDAY THROUGH MONDAY/... Key Message(s): - Near average temperatures Friday, gradually warming this weekend as upper ridging likely returns. - More typical isolated to scattered convection expected during the extended, lower during the weekend. Upper trough lifts out of the CONUS on Friday as ridging likely returns to the Southeastern US. This should result in a gradual warming trend during the long term with decreasing rain chances. Friday may end up similar to Wednesday and Thursday with near to slightly above normal temperatures and scattered showers and thunderstorms. Rain chances should be lower and more isolated this weekend due to the presence of the aforementioned ridging. Rain chances may increase again early next week as a cold front attempts to break through the ridge. && .AVIATION /10Z TUESDAY THROUGH SATURDAY/... VFR conditions likely Tuesday morning, with scattered convection likely in the afternoon-evening. Calm and VFR conditions are expected through Tuesday morning for the TAF sites. Cannot totally rule out some morning river fog at AGS or OGB, but confidence far too low for a mention in the TAFs. Winds will then develop out of the south after 15z with typical summer cu developing. Scattered showers and storms are likely this afternoon-evening, but exact timing and convergence confidence only warrants a PROB30 for now. But at least some impacts, vicinity or at the site, are expected for all the TAF sites at some point this afternoon. Convection should calm down after 00z with some overnight fog and stratus possible depending on rainfall totals and coverage.expected again so included a PROB30 all terminals. EXTENDED AVIATION OUTLOOK...There is the possibility of diurnally driven showers and thunderstorms this week with the potential for periodic restrictions. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$ SYNOPSIS... NEAR TERM... SHORT TERM... LONG TERM... AVIATION...