Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
088 FXUS62 KGSP 070016 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 816 PM EDT Mon Oct 6 2025 .SYNOPSIS... High pressure continues to control the pattern through Tuesday, with low rain chances and a slow warming trend. A cold front arrives Wednesday, which will bring a chance for showers and thunderstorms across the area. Much drier and cooler weather is expected behind the front during the latter half of the week. && .NEAR TERM /THROUGH TUESDAY/... 1) A few isolated showers linger into the overnight along and west of I-26. 2) Warm overnight lows under mostly cloudy skies and patchy fog. As of 110 PM EDT Monday: Starting off the new week in a relatively quiet pattern. Aloft, the southeast remains in typically broad flow with an upper low across southern Canada carving a trough down into the Midwest. At the surface, a strong and persistent Bermuda high amplifies westward into the region, advecting moisture from the Atlantic. The cloud cover and moisture return carves around the CWA toward the west. A few showers could linger overnight across the far western NC mountains as E/SE surface winds provide moderate isentropic ascent. PoPs in the 20-30% range will continue thru about 06z, mainly near the Blue Ridge Escarpment. For Tuesday, the high pressure axis wobbles westward, reducing precip chances across most of the area. There could be a stray shower across the mountains near the TN/NC border. Will keep a slight chance PoP (15-20%) in place for this area. Again, nothing severe is anticipated Tuesday either. Overnight temps remaining mild in the 60s, thanks to the surface moisture. Some break up of the clouds is expected Tuesday, allowing temps to be a few degrees above normal, mainly upper 70s to lower 80s. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/... As of 1217 PM Monday: Model guidance is in good agreement that an upper trough will swing across the Great Lakes and Ohio Valley tomorrow night into Wednesday. The Southern Appalachians will remain in the base of the trough with the strongest forcing for ascent displaced north of the area. Nonetheless, at least modest height falls in concert with the approach of a surface cold front should prove sufficient to instigate a band of showers that will approach the mountains tomorrow night. This activity is then forecast to shift east across the rest of the area during the day on Wednesday. Around 1000-1500 J/kg of surface-based instability may be realized ahead of the boundary during peak heating, but poor lapse rates and near parallel frontal orientation relative to the deep-layer shear vectors doens`t bode well for organized severe weather, although an isolated strong storm cannot be ruled out. Overnight lows tomorrow night will be a good bit above average owing to widespread cloud cover and dewpoints in the mid 60s. Daytime highs on Wednesday, mainly ahead of the front/precipitation, will once again be warm in the low to upper 70s. A few readings near the 80 degree mark cannot be ruled out owing to compressional warming ahead of the boundary. Noticeably cooler and drier air advects into the region behind the front Wednesday night into Thursday as a sprawling surface high settles across the Great Lakes. Daytime highs on Thursday may struggle to reach the 70 degree mark across much of the area. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... As of 1258 PM Monday: Forecast confidence begins to lower late week into the weekend as guidance depicts a trailing piece of energy within the southern stream diving across the Lower Mississippi Valley and into the southeast states by Friday. Several members attempt to close off an upper low which then interacts with a coastal baroclinic zone and induces surface cyclogenesis along the Carolina coast. At the same time, a compact closed upper low is progged to be diving across the Great Lakes and into the Ohio Valley, which further complicates the evolution of the synoptic pattern and subsequent interaction between the two closed lows. As of this writing, current expectations are for any coastal low and associated precipitation to remain east of the area with dry and cool northerly flow on the western flank of the cyclone. Uncertainty is introduced with regards to the Great Lakes upper low and whether it can "pull" the coastal low farther northwest in response to lowering heights. Will maintain a dry forecast for now, but will have to watch how the forecast evolves through the week. Temperatures slowly modify through the end of the week into the weekend, but still below seasonal averages. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... At KCLT and elsewhere: A mix of VFR/MVFR conditions to start the TAF period as moist southeasterly flow persists thru tonight. Most sites are improving to VFR this evening, but will likely go MVFR or IFR overnight. Guidance is mixed on whether some patchy dense fog can form. But more likely stratus will limit fog development. Will continue a TEMPO at all sites for late tonight thru about 12-13z Tuesday. The confidence remains low for KCLT, so have gone less pessimistic in the TEMPO. IFR to MVFR cigs will likely be widespread thru late Tuesday morning, before returning to VFR by early afternoon. Wind will be light, becoming S/SE at all sites by Tuesday aftn. toward the end of the TAF period. Outlook: A cold front increases rain chances and restrictions, Tuesday night thru Wednesday night before drier conditions return for the remainder of the week/weekend. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CAC NEAR TERM...ARK/CP SHORT TERM...TW LONG TERM...TW AVIATION...ARK