Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
221 FXUS62 KCAE 301757 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 157 PM EDT Wed Jul 30 2025 .SYNOPSIS... Summer heat and humidity continues into the end of the week. This heat spell is expected to break as a cold front is expected to bring cooler conditions by the weekend. Afternoon showers and storms should occur each day through the period. && .NEAR TERM /THROUGH TONIGHT/... Key Message(s): - Warm and humid this afternoon with scattered to numerous showers and storms before this activity wanes overnight. Some stubborn stratus and debris clouds lingered across much of the Midlands this morning and into early this afternoon, leading to temperatures being a couple degrees behind, in the upper 80s. With the scattering of some cumulus now, most areas should reach the low to mid 90s in the coming hours, warmest in the CSRA where there was less cloud coverage this morning. The aforementioned clouds have created a differential heating gradient which can be seen well on satellite with generally flatter cumulus in the Midlands and more agitated cumulus into the CSRA and just north of the Pee Dee region. A couple showers and weak storms are starting to form in these regions as MLCAPE approaches 1000-1500 J/kg and PWAT`s remain between 2.2-2.3". Outflow released from these initial storms should aid in increasing coverage across the FA this afternoon and evening where torrential rain, frequent lightning, and isolated strong gusts would be the primary risks, though weaker mixing from the increased cloud cover today has limited DCAPE values. Overall steering flow is still rather weak, though it is a bit better than yesterday with 10- 15 kts of flow in the 600-300 mb layer. Still, slower storm motions, long/skinny CAPE profiles, and high PWAT`s bring the risk for locally heavy rainfall and possibly a couple spots of flash flooding in these storms. This activity is expected to continue into the early overnight hours before dissipating early Thursday morning. && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... Key message(s): - Temperatures return to closer to normal, but heat index values continue to hold in the 100F-108F range. - Scattered showers and thunderstorms remain possible, with strong storms and isolated flash flooding possible. Thursday and Friday should be the last very hot and humid days of this extended stretch of above normal temps, thankfully. The ridge will continue to break down both days as the well anticipated trough digs into the eastern CONUS. Strong convergence aloft will continue to foster an anomalous (99th percentile) surface high pressure across the Great Lakes, slowly pushing eastward both days. Our weather will not be significantly different than we have seen the past couple of days. PWs are likely to remain in the 2"-2.4" range, sandwiched between the ridge to our south and the approaching trough to our north. Scattered to numerous showers and thunderstorms are likely by the evening hours both days. Heat will continue to be anomalous given the robust moisture profiles in place. A Heat Advisory is not anticipated tomorrow but there is some guidance suggesting we may need one on Friday. COnvection has slowed slightly in the guidance, with the front approaching Friday evening as opposed to Friday afternoon. With longer duration sunshine and high surface dewpoints, we may get to Heat Advisory criteria on Friday afternoon. We`ll need to keep a close eye on CAMs tomorrow to get a better handle on the timing of convection. Regardless, it does look like coverage will be even greater on Friday evening and Friday night than the previous days given forcing along the front and a bit of upper-level support from a weak jet streak to our north. So flash flooding is definitely possible, with WPC highlighting our entire area in a Slight Risk for Excessive Rainfall. Highs both days should be in the mid to upper 90s with lows in the mid 70s. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Key message(s): - Cold front moving through by Saturday will bring a period of below normal temperatures to the region. - Scattered to numerous showers/storms continue through much of the period - A focused threat for heavy rainfall is expected on Fri/Sat along the cold front The beginning of our "cool" stretch of weather is expected on Saturday, lasting through early next week. While there remain pretty significant differences between the GFS and ECM solutions and where they place the front, the model consensus is that below normal temperatures will dominate the forecast from Saturday through at least Monday. The big fly in the ointment with the forecast is surrounding the eventual location of the front itself. While it is forecast to push through the area on Friday night and Saturday, the location of it thereafter is not agreed upon by guidance. The GFS is the most aggressive model, pushing it well south of the forecast area. The ECMWF keeps the front across the far southern part of the forecast area, which seems a bit more realistic to this forecaster. This is important for sensible weather because the closer the front is to the area, the more widespread rain/storms will be across the area. What is clear is that temperatures look like they`ll be 5F-10F below normal during the afternoon hours, with the possibility that it is even cooler than that if we have widespread showers and storms (such as the ECMWF shows). Guidance does continue to show cooler temps hanging on next week, albeit with temps getting closer to normal in the upper 80s. PoPs look to remain above normal Monday and beyond given continued presence of low-level moisture & a broad upper trough persisting across the southeastern US. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... Periods of restrictions possible this afternoon with scattered to numerous showers/storms then VFR conditions expected the remainder of the period at this time. Stratus was slow to mix out this morning with periods of MVFR ceilings still being seen at CAE/CUB, but this is finally lifting with scattered cumulus beginning to take over. Winds remain light and fairly variable early this afternoon as showers and storms are starting to form across the region. The Columbia and Augusta TAF sites already have vicinity showers and are the most likely to experience restrictions associated with thunderstorms between 19- 23z. OGB will also have this chance but with how radar is trending at the moment, think this activity could impact the terminal a hour or so later than the other TAF sites. Majority of this activity wraps up between 23-02z, but could remain in the vicinity of the TAF sites into the early overnight hours. Tonight, winds remain light and variable with some debris clouds expected. The overall signal in model guidance for fog and/or stratus tonight is lower (around 20- 25%), but with high low level moisture, FEW to SCT stratus could be possible and thus I added mention of this at the TAF sites, but confidence in restrictions is not very high at the moment. Thursday morning then brings winds that become more southwesterly and scattered cumulus until the end of the period. EXTENDED AVIATION OUTLOOK...Afternoon convection could bring brief periods of restrictions through late week and into this weekend as coverage is expected to continue to be higher. With increasing moisture, cannot rule out a couple mornings with patchy stratus or fog. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$