


Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
428 FXUS62 KCAE 100145 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 945 PM EDT Wed Jul 9 2025 .SYNOPSIS... A bit cooler today with widespread showers and storms likely as an upper trough approaches. The threat for damaging winds and flash flooding will exist both today and Thursday with heavy rainfall expected. The upper trough is replaced by ridging late in the week and this weekend, allowing temperatures to slowly rise with typical summertime showers and storms. && .NEAR TERM /UNTIL 7 AM THURSDAY MORNING/... Key Message(s): - Isolated to scattered convection overnight with possible flash flood threat. Widespread convection has diminished across the forecast area this evening but regional radar shows additional scattered showers and thunderstorms developing across central GA moving toward the upper CSRA possibly driven by weak shortwave energy on the leading edge of the upper trough axis. The atmosphere remains quite conducive for heavy rainfall with PWATs around 1.9-2.1 inches and dewpoints generally in the lower 70s. Hi-res guidance suggests this activity will slowly move into the area overnight impacting the northern and central Midlands through the night. Severe storm threat appears low with some stabilization of the atmosphere where widespread rain occurred and think the flash flood threat is higher, although mesoanalysis continues to show MLCAPE values 1500-2000 J/kg along the I-85 corridor into the western Midlands. Widespread cloud cover and additional precipitation likely to limit radiational cooling and with temperatures already in the lower to mid 70s, overnight lows should not be too far off from these values. Patchy to possibly widespread stratus/fog cannot be ruled out given the amount of rain that occurred over parts of the forecast area. && .SHORT TERM /7 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... Key Message(s): - Potential for strong to marginally severe storms mainly Thursday, but possible again on Friday. - The Flash flood potential continues through the short term as high moisture and weak steering flow continues. An active short term period continues to be expected as the upper trough works through the FA Thursday before beginning to exit toward Friday evening and overnight. Forcing from the trough will continue to influence sensible weather each day where the whole CWA is outline in a Slight Risk (level 2 out of 5) for severe weather on Thursday and a Marginal Risk on Friday (level 1 out of 5). For Thursday, weak upper forcing along with some surface moisture convergence should drive scattered to widespread showers and storms across the area during the afternoon/evening. The environment has long skinny CAPE profiles with MLCAPE on the order of 2000-2500 J/kg and PWAT`s that remain near 2.0-2.2", though the degree in which the atmosphere destabilizes is a bit uncertain as increased cloud cover is expected Thursday morning into the afternoon. Deep layer shear remains weak, but has slightly increased from previous forecast soundings to around 15 kts. Due to this, a couple loosely organized clusters could form and possibly grow upscale some if a strong cold pool develops. The very moist soundings, and at least modestly steep 0-3km lapse rates, bring the main threat of damaging winds from potential wet downbursts, but the other concern, especially depending on which locations see rainfall today, will be the potential for isolated spots of flash flooding. Currently, the CWA is outlined in WPC`s Marginal Risk (level 1 out of 4) for excessive rainfall Thursday but a Slight Risk (level 2 out of 4) does extended into the Pee Dee region. With weak steering flow once again overhead, slow storm motions are expected and when coupled with long/skinny CAPE profiles over a deeply moist atmospheric column, efficient rainfall is likely where the 12z HREF LPPM highlights localized spots of 2-4" being possible. Again, the areas at highest risk for this potential will partially be driven by rainfall received today and how soil moistures and local basins respond. This activity is expected to dwindle in coverage and intensity into the overnight hours. Friday sees the trough pivot overhead and finally out of the region by the evening and overnight, though PWATs remain near 2" still with a possible shortwave that reaches the FA by the early afternoon. This should drive another round of scattered to widespread showers/storms, with a couple on the strong side possible, again due to the potential for downburst winds from precip loaded downdrafts as shear and steering flow remain weak. Like Thursday, some enhanced cloud cover to start the day brings in uncertainty in how much instability can build. With PWAT`s slowly lowering due to moisture transport vectors turning a bit more westerly and upper forcing slowly moving out, the potential for isolated flash flooding in spots is a bit lower than Thursday, though this could easily change based on where slow-moving convection moves over today and Thursday. Showers/storms look to move out with the upper support during the evening and overnight as ridging slowly replaces the trough. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Key Message(s): - Temperatures return to above normal values this weekend into Monday as upper ridging redevelops. - Shower/storm chances become more diurnally driven. Upper ridging continues to be expected to take grip through the weekend and into the early week, leading to increased temperatures and heat indices that near 105F mainly Sunday and Monday. Returning seasonable moisture under the ridge brings typical diurnal shower/storm chances each day before there is a least a weak signal in global models that the ridge could break down slightly toward Tuesday, possibly bringing closer to normal temperatures and increased PoP`s each day. && .AVIATION /01Z THURSDAY THROUGH MONDAY/... Lingering showers continuing over the terminals, although there are not leading to any restrictions. With widespread rainfall today, another chance tonight that restrictions develop over the terminals as MVFR fog or ceilings with plentiful low level moisture in place. Guidance still remains mixed on this potential, however, so have included it in a TEMPO group. Also uncertainty as to some convection to the west of the terminals, but hires guidance continues to indicate it will dissipate as it approaches the terminals. Additional convection develops tomorrow afternoon but uncertain that it will be before 18z. 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. && $$