Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
364 FXUS62 KGSP 032350 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 750 PM EDT Wed Sep 3 2025 .SYNOPSIS... A weak cold front approaches from the northwest on Thursday and may bring another round of showers and storms to the mountains and portions of the foothills. Temperatures remain at or below seasonal normals through Thursday. A warming trend returns Friday into the weekend ahead of another advancing cold front. Rain chances return this weekend and may linger into early next week depending on whether the front fully clears the area or stalls across the region. && .NEAR TERM /THROUGH THURSDAY/... As of 7:45 PM EDT Wednesday: Showers have completely ashed out acrs the cwfa. With generally fair conditions lingering into the overnight hours, there remains the likelihood of locally dense mtn valley fog/stratus. Low temps are still expected to be about a category below normal for early September. Otherwise, the eastern 2/3 of the CONUS will remain under very broad upper trofing thru the near-term period and beyond. Another upper impulse/shortwave will move thru the longwave trof axis on Thursday, but it appears weaker than the one moving over our area today. At the sfc, weak high pressure will linger over the Eastern Seaboard thru early Thursday before getting pushed off the coast later in the day. At the same time, a moist cold front will move thru the OH Valley and approach the western Carolinas from the NW, but is expected to stall out as it moves into the NC mtns later on Thursday. As a result, low-level flow will remain S to SW across most of our fcst area thru the day. Most of the guidance has some amount of shower development overnight/early Thurs across northern GA/eastern TN that may work its way into our western zones before daybreak. There is not as much mid-level cloudiness in the guidance as we have seen the last couple nights, but we could see more low clouds in the strengthening SWLY WAA flow that may limit mtn valley fog development. As the day progresses, another round of sct showers and thunderstorms is expected to develop over the NC mtns and NE GA and track eastward. With the front stalling over our western zones, any convective activity is expected to diminish the further east it moves with it not likely to reach our eastern zones. Nonetheless, we could see more robust thunderstorms over the mtns and into the foot- hills on Thursday as decent sfc-based instability and 30 to 40 kts of bulk shear are fcst. As such, SPC has this area in a Marginal Risk for severe storms with damaging straight-line winds being the main hazard. The main unknown will likely be how much any lingering cloud cover will impact destabilization over the mtns/foothills on Thursday. If cloud cover persists longer than expected, these areas won`t destabilize as much and stronger storms would be less likely. Otherwise, temperatures will continue to warm with highs near climo across our lower terrain, but still about a category below climo over the mtns. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... As of 1155 AM Wednesday: A seasonably strong mid level low will be in place across southern Canada and the Great Lakes and Ohio Valley states through the short range period. Heights will rise south of this feature across our area on Friday and Saturday. This will lead to the warmest temperatures in around 2 weeks both days. Expect highs to be 3-6 degrees above normal in the Piedmont and 1-3 degrees above normal in the mountain valleys. A spoke of energy will push a cold front toward the area on Saturday. This will lead to a chance of showers and thunderstorms across much of area with the highest pops in the mountains. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 1210 PM Wednesday: The cold front will push into the area on Sunday bringing a continued chance of showers and thunderstorms. Surface high pressure will move from the Ohio Valley into the Northeastern states early next week. This will lead to cold air damming early next week and much cooler temperatures. Highs Monday and Tuesday may be as much as 10 degrees below normal. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... At KCLT: Remaining mostly clear with just a light SW wind continuing into Thursday morning. The sfc pressure gradient tightens out of ahead of an approaching cool front leading to gusty SW winds developing by early afternoon. At this point, any storms that are trigger by said front should remain west of the terminal into Thursday evening. Elsewhere acrs the FA: The main concern for tonight is the development of locally dense mountain valley fog. Given the probability of mostly clear conditions it is becoming more likely that KAVL will have to deal with a period of IFR during the pre-dawn hours. Otherwise, the daytime concern will revolve around thunderstorm development, perhaps as early as late morning in the NC mountains progressing into the piedmont by mid-afternoon. Outlook: Scattered afternoon/evening convection is expected to linger across the higher terrain into Thursday evening with chances diminishing on Friday. Nocturnal fog and/or low stratus will be possible each morning, especially in the favored mtn valleys. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...CSH/JPT SHORT TERM...SCW LONG TERM...SCW AVIATION...CSH/JPT