Area Forecast Discussion
Issued by NWS Columbia, SC
Issued by NWS Columbia, SC
749 FXUS62 KCAE 032341 AFDCAE Area Forecast Discussion National Weather Service Columbia SC 741 PM EDT Wed Sep 3 2025 .SYNOPSIS... Temperatures warming to near normal Thursday ahead of a diffuse cold front where it should remain mostly dry. Above average temperatures Friday and Saturday before a stronger front moves into the area late this weekend leading to chances for rain into early next week. && .NEAR TERM /THROUGH TONIGHT/... Key Message(s): - Dry high pressure remains in place overnight. Regional radars showing the closest rainfall is west of the spine of the central Appalachians. With dry surface high pressure still in control over our area, we will not see any of that rainfall making it here overnight. Late tonight, the surface high will be slowly moving off to the north and east of the area. As this occurs there may be a slight increase in low- level moisture towards morning, and with mostly clear skies and light winds, can not rule out some patchy ground fog. Overnight lows still expected in the lower 60s. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... Key message(s): - Warming trend continues through the end of the week while staying mostly dry. 500mb heights remain neutral through Thursday as a weak shortwave may pivot toward the upstate through the day before modest height rises are expected into Friday. Low level flow turns out of the southwest through the short term period, leading to increased warm advection with temperatures that are near normal Thursday then above normal into Friday. This flow should also increase moisture some as PWAT`s raise to between 1.3-1.5", highest in the upstate and into the northern FA on Thursday before this axis shifts south Friday. As the now occluded surface low in southern Canada continues to slowly retrograde westward Thursday, a weak surface front pushes into the Tennessee Valley, but majority of model guidance is showing this front becoming increasingly diffuse near the Appalachian mountains. With this front and a weak shortwave moving across the mountains and the upstate, showers and some storms are expected to develop in the upstate during the afternoon Thursday. High res models and the deterministic NAM, GFS, and ECMWF keep this activity north of the CWA with forecast soundings indicating plenty of dry air aloft. While a mostly dry day is expected, a shift a bit more south in the shortwave could lead to a shower or weak storm sneaking into our northern tier of counties. The 500 mb height rises, general lack of forcing, and substantial dry air aloft should bring a dry day Friday as well. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Key message(s): - Above average temperatures Saturday before cooler conditions set in to start next week. - Cold front moves through late Saturday and into Sunday, leading to a slight chance to chance for showers and some thunderstorms. - Slight chances for rain carry into the early week. There is not much change in the extended forecast outside of PoP`s that have slightly increased for Sunday. There remains high confidence in above normal temperatures Saturday as modest height rises and warm advection pushes into the area, along with increasing moisture with PWAT`s now raising near to just above 1.5". This should lead to hot and humid conditions Saturday, but with dry weather likely prevailing as the main cold front remains to our NW most of the day. This front then is expected to near the FA late Saturday before working through the area on Sunday. There remains some discrepancy amongst deterministic guidance on the depth of moisture and strength in moisture transport ahead of the front, but in general at least slight chances for showers and some thunderstorms will exist Sunday afternoon as PWAT`s approach 115-120% of normal (per GEFS and EC Ensemble mean solutions) with decent convergence along the front. The thunderstorm potential appears to have increased some with majority of EC Ensemble members showing MUCAPE over 500 J/kg, but GEFS members are not as excited so some uncertainty remains, especially with the exact timing of the front. At least a slight chance for showers and storms seems reasonable at this time. Heading into the early week, temperatures cool back below normal as strong high pressure (1-1.5 standard deviations above normal) moves into the Mid Atlantic and the upper East Coast. This should turn low level flow increasingly out of the northeast, bringing a cooler near surface air mass. Flow aloft looks to be a bit more southwesterly and thus increased moisture aloft over-riding this cooler low level airmass could bring slight chances for showers into the early week. It could also be a bit breezy at times early next week as both the ECMWF and GFS show some inverted troughing off the coast of the Carolina`s leading to an increased pressure gradient. && .AVIATION /00Z WEDNESDAY THROUGH MONDAY/... VFR conditions likely through period. Mainly clear skies being seen on satellite imagery at the start of the TAF period, with some higher level clouds passing over the area overnight. Much of the same for the daytime hours tomorrow, although some low to mid level clouds are also likely to develop. Typical light and variable to calm winds expected overnight followed by south-southwest winds increasing to between 5-10 kts after about 14z. There remains a chance for patchy fog, particularly at CAE, AGS, and OGB, due a slight increase in low level moisture, but confidence is still too low to go any lower than VFR in the TAFs at this time. EXTENDED AVIATION OUTLOOK...Showers possible late Thursday could yield some restrictions but confidence in impacts is low. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...None. GA...None. && $$