Area Forecast Discussion
Issued by NWS Greer, SC
Issued by NWS Greer, SC
274 FXUS62 KGSP 081811 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 111 PM EST Sat Nov 8 2025 .SYNOPSIS... A few strong to severe thunderstorms can`t be ruled out this afternoon and evening across portions the western Piedmont. A strong cold front makes a full passage Sunday and will filter in an arctic airmass Sunday night through Tuesday. Mountain snow along the NC/TN border is expected Sunday night through Monday. Temperatures gradually rebound after Tuesday, with dry conditions expected. && .NEAR TERM /THROUGH SUNDAY/... As of 1240 pm Saturday: The latest water vapor imagery depicts a very broad/low-amplitude upper trough centered just east of the Miss River Valley early this afternoon, with a train of mostly weak short wave short wave troughs from the Ohio Valley NW into the Canadian Prairie. Surface analysis depicts a weak/quasi-stationary frontal boundary bisecting our CWA, with slightly warmer/clearer conditions indicated south of the boundary...roughly across the southern half of the area. The latest SPC Mesoanalysis indicates 500-1000 J/kg of sbCAPE from the Lakelands/upper Savannah River Valley into north GA, with cumulus becoming increasingly congested/agitated across north and central GA. Convection-allowing models remain consistent in allowing scattered deep convection to develop along/south of the boundary...from central GA into the southern half of our area by late afternoon, continuing into the evening as mean cloud-bearing flow allows activity to move rather quickly E/NE toward the Charlotte Metro Area. Deep layer shear will be more than adequate for organized cell structures, including the potential for rotating updrafts/supercells in the more unstable air (e.g. across the southern tier of our counties.) The main severe threats would be from large hail with any rotating storms, as well as damaging wind gusts. Low level shear/helicity parameters are quite underwhelming, but a brief, weak tornado cannot be ruled out with any supercell structures. Scattered convection will move east by around midnight...or shortly thereafter, with another round of widespread low clouds and fog...perhaps locally dense expected by daybreak. Min temps will be well above normal in the cloudy/humid conditions. The upper trough will continue to deepen/amplify as it approaches the Appalachians on Sunday, with attendant strong cold front forecast to push into western North Carolina by late morning...pushing east of the CWA by the end of the period. Temperatures will begin falling across the mountains during the afternoon, with northwest upslope flow becoming established...and attendant scattered showers expected...especially across the counties bordering TN. Rain is expected to change to snow above ~4000ft by the end of the period as snow levels steadily fall in the strong cold advection. Other than the NW flow precip...the front is unlikely to bring any showers to the forecast area, as moisture and forcing are expected to become maximized to our east. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... As of 1258 PM EDT Saturday: Strong CAA and steep height falls will be in the midst of entering the CWFA as a digging upper trough parks over the MS Valley and the attendant cold front should be in the process of exiting the eastern portions of the CWFA by the start of the forecast period. Low-level flow will turn west-northwesterly with strong vort lobes traversing across the area and moisture being advected off the Great Lakes. This combined with tanking snow levels and mechanical lift along the NC/TN border, expect northwest flow snow to crank up overnight Sunday. Tight pressure gradient (4-6mb) with ongoing snow and dynamical features aloft will support sporadic blizzard conditions at the highest elevations (>4000`) along the immediate Tennessee border. Soundings from the CAMs are picking up on very shallow instability, which should only increase snowfall rates, especially in the favorable upslope areas in the Smokies, northern Madison County, and the Roan Mountain area. Perhaps an instance of thunder snow can`t be ruled out either, but good luck finding the exact location where this might occur. The rest of the area remains quiet, but the CAA will uptick winds overnight Sunday. Despite temperatures getting close to freezing and matching up well with frosty values outside of the mountains, winds will be elevated too much for frost to develop and will keep temperatures too warm for a Freeze Warning. Overnight lows on Sunday will run 5-10 degrees below normal. Northwest flow snow will linger throughout the day Monday, but will be off and on as the area will be in between two large areas of vort energy. Downslope flow should help locations outside the NC/TN border to remain partly to mostly sunny, especially during the first half of the daytime period. Some changes will be noticeable by the evening hours as a bowling ball of vort energy associated with the closed upper low swings into the area. Enough dynamical forcing and low snow-levels could allow for the reinforced northwest flow snow to break containment east of the mountains depending on the orientation of the low. This provides an AFD mention for possible flurries across the western Piedmont and foothills and Upstate SC, but confidence is not high enough for a mentionable PoP. Seems like model guidance are in good agreement with the placement of the low and the timing happening after peak heating to allow for such setup to occur. Flurries will not be widespread, but a few locations may get lucky enough to see November flakes outside of the mountains. This will also be the best time period for some of the other mountain locations that don`t normally feel the impacts of northwest flow snow to get in on the action as well, with little to no accumulation expected in the locations outside of the typical west to northwest facing slopes. With the impressive dynamics of this system and the Great Lakes connection, will not be surprised to see snow totals exceed expectations in some of the ridgetops and favored upslope areas. With that being the case, the latest snow totals match up well with the overall thinking and supports 6-10" at the highest elevations in the Smokies, and a solid 1-3+" along the immediate Tennessee border, with less than an inch elsewhere. Temperatures will be cold on Monday as afternoon highs will be colder than what we receive in the middle of January. Afternoon highs will run 15-20+ degrees below normal. The bowling ball closed upper low should shift east of the area by daybreak Tuesday as dry air entrainment gets going and essentially shuts off the northwest flow snow maker. The coldest night of the season will be Monday night as CAA fully settles in and very cold thicknesses remain in place. Expect a hard freeze across the entire CWFA with most locations in the 20s, teens and single digits expected for the higher elevations. In this case, all of the non-mountains zones should expect a Freeze Warning Monday night into Tuesday morning. Factor in the elevated wind gusts and the wind chill values will be near or below 0F above 4500`, with single digits in the lower elevations, and teens for a large area outside of the mountains. Doesn`t meet Cold Weather Advisory, but will be close. The trough axis shifts east of the area on Tuesday and a strong surface high will settle over the eastern half of the Gulf. Expect drier conditions and mostly sunny skies, with a gradual rebound in temperatures, but not much. Afternoon highs on Tuesday will continue to run 12-18 degrees below normal. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... As of 106 PM EDT Saturday: Broad upper troughiness should linger overhead through a good portion of the workweek as the airmass continues to modify Wednesday and beyond. Model guidance continue to hint at a relatively diffuse cold front to move in Thursday associated with a passing shortwave over the northeastern CONUS. Expected to be moisture starved though as no real return flow and weak forcing won`t be able to squeeze much of a QPF response across the CWFA. However, a reinforcing shot of drier air behind the front may cause some fire weather concerns Thursday and Friday as this will lower RH values. Otherwise, dry conditions are expected as temperatures return to near-normal or slightly higher values by next Thursday and linger through the end of the forecast period. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... At KCLT and elsewhere: Cigs have finally scattered and/or lifted to VFR across the Terminal Forecast Area this afternoon, although can`t rule out brief periods of MVFR here and there for the first couple of hours of this forecast period. Meanwhile, moisture will remain adequate for some modest destabilization to occur in light of the strong heating that is underway, especially across the southern half of the area. A weak frontal boundary is expected to provide a focus for development of scattered deep convection late this afternoon into the evening...mainly impacting the upstate SC terminals and KCLT. Convection should primarily be of the shower variety, but isolated/widely scattered thunderstorms are expected, with the probability of such increasing toward the southern part of the area...such that a tempo for TSRA is included at KAND after 22Z. VCSH and/or Prob30s for SHRA appear to be the best forecast at the other terminals, but will need to monitor trends closely for potential AMD to include TS at the other Upstate terminals and KCLT. Convection is expected to diminish and/or move east of the area around, or shortly after midnight, with the potential for crashing cigs and possibly reduced visby increasing from late evening through the overnight. LIFR cigs are forecast at most sites between 06-12Z Sunday. The visby forecast is primarily MVFR, but can`t at all rule out something lower, especially at the NC terminals. Skies should clear at most terminals by late morning, with VFR expected at most sites from ~15Z on. Winds will generally be light/variable until the daylight hours Sunday, when they are expected to become SW at 5-10 kts at most sites, with a further increase and some gustiness expected Sunday afternoon. Outlook: A strong cold front will cross the area from the west by late Sunday, bringing gusty winds, some low clouds and RA/SN showers to the mountains. Precipitation may linger Monday across the mountains. Gusty winds linger through Monday into Tuesday. Dry conditions Wednesday and Thursday with afternoon gusts possible. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CAC NEAR TERM...JDL SHORT TERM...CAC LONG TERM...CAC AVIATION...JDL