FXUS62 KGSP 221806 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 206 PM EDT Sat Aug 22 2026 .WHAT HAS CHANGED... Revised analysis of a highly isolated threat of strong to severe thunderstorms this afternoon and evening. No major changes to overall thinking beyond tonight. && .KEY MESSAGES... 1. Isolated showers and thunderstorms remain possible in the mountains and foothills through this evening. If a thunderstorm develops it could pose a risk of damaging winds. 2. Drier weather returns Sunday through early next week, followed by daily shower and thunderstorm chances returning Wednesday through Friday. && .DISCUSSION... Key message 1: Isolated showers and thunderstorms remain possible in the mountains and foothills through this evening. If a thunderstorm develops it could pose a risk of damaging winds. A stubborn stratus deck covered most areas south and east of the Blue Ridge Escarpment through midday today. This deck should continue to erode through the afternoon. A weak convergence zone is analyzed near the Escarpment, arguably a lee trough but also possibly due to differential heating near the edge of the cloud deck. This already produced some brief and isolated showers northeast of Asheville which have now dissipated. A better defined surface front is now near the Ohio River and will make slow SE'wd progress through tonight. Profiles remain moist and warm near the surface but some drying is occurring aloft, such that prog soundings for the afternoon feature large SBCAPE as well as large DCAPE. A vort axis associated with a weak shortwave or MCV, now in eastern KY/TN, will advect slowly over the Appalachians later this afternoon and evening. With relatively fast flow at 500mb, 0-6km shear is upwards of 30 kt. As the shortwave impinges on the aforementioned weak boundaries over our area, there is reason to believe that an updraft could initiate and a strong to severe storm could quickly develop. CAMs however generally develop only sparse convection this afternoon. The 3km NAM keys more on the OH Valley front as a trigger mechanism, showing small clusters of storms evolving to our NW through late evening, bearing updraft helicity streaks. SPC highlighted the NW half of our area in a Marginal Risk which isn't wholly unreasonable, though given the lack of model response, we only have justification for isolated or widely scattered shower/storm mention. Thus, while storms overall look limited in scope, radar and satellite trends bear watching closely as the few storms that form certainly may be impactful. Key message 2: Drier weather returns Sunday through early next week, followed by daily shower and thunderstorm chances returning Wednesday through Friday. The surface front should settle southward most of the way through the CWA by Sunday morning. Closed 500mb low will remain over the northern Great Lakes, only slowly progressing eastward into the St Lawrence Valley as vortices rotate through. The axis of the surrounding trough in turn makes slow progress across the Eastern Seaboard through the early week period; deep anticyclone will remain over the southern Rockies and Plains. NW flow should continue over our area in the low levels with westerly upper flow; some mixing of drier air should occur diurnally on Sunday, effectively pushing the front southward, and it then should stall over the Deep South by Monday. The upshot for our area still looks to be mostly sunny skies and minimal chances for convection Sunday and Monday. Temperatures will remain near normal though the humidity will be low. We may experience height falls Tuesday with another weak shortwave entering the eastern trough, so it is not out of the question the front will reactivate on our southern fringe, and allow some convective activity to develop along that part of our CWA border. However, most indications are we will remain on the cool/dry side of the front and humidity and PoPs are still forecast below normal. Height falls begin more earnestly Tue night into Wed as better defined shortwave enters the MS Valley and the front thus is more likely to shift northward. For Wednesday in turn we expect seasonably hot and humid conditions to return, with PoPs in the usual 20-30% range; chances increase Wed night and Thu as the trough interacts with the front. Though the large scale pattern looks likely to feature a western ridge and eastern trough through the end of next week, models differ as to whether a drying cold front will follow the shortwave. and for now the safest bet is to assume unsettled weather (high humidity and frequent chances for showers/storms) will continue to the end of the period, though temperatures will be advertised near or even slightly below normal. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... At KCLT and elsewhere: Stratocu deck at FL020-030 appears to be in the process of eroding at issuance time. Sites may go back and forth between MVFR and VFR very early in the period before the deck scatters and lifts. Once the deck scatters winds should be predominantly SW'ly this aftn, except NW at KAVL, though with weak pressure gradient periods of VRB also are likely. A few SHRA/TSRA may occur in the lee of the mountains through sunset, and a few showers could regenerate along the west slopes of the Appalachians tonight. However none of those are likely enough to affect TAF sites to warrant a mention. A dry frontal boundary will push through the area tonight and may lead to brief low-VFR to MVFR cigs though that is expected to be of little impact; winds turn NW'ly with the front as well. Conditions would appear favorable for mountain valley fog/stratus to affect KAVL, though with winds picking up behind the front they could stay too mixed. For now, have improved cigs to IFR, compared to the LIFR previously forecast, and if confidence increases on winds being steadily 6-7 kt, the restrictions may need to be completely removed. The drier post-frontal airmass suggests VFR conditions Sunday with near zero chance of SHRA/TSRA. Outlook: No significant chance of convection until Wednesday. Mountain valley fog and low stratus is possible each morning. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ JCW