256 FXUS62 KGSP 072358 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 658 PM EST Sun Nov 7 2021 .SYNOPSIS... Dry and warming high pressure will continue across the region through the middle of the week. A significant storm system is then expected to bring a return of unsettled weather late in the week. Much cooler temperatures are expected to arrive next weekend. && .NEAR TERM /THROUGH MONDAY/... As of 655 PM EST: Quiet weather continued this evening. Forecast on track with good radiational cooling conditions with winds dropping off and clear skies and low dewpoints in place. Tweaked mountain valleys a bit colder and ridgetops a bit warmer as a fairly strong low level inversion is expected tonight. The cooler mountain valley temps may support patchy freezing fog by sunrise tomorrow with the Little Tennessee Valley and Lower French Broad Valley near the TN border the most likely recipients. Otherwise, the upper ridge axis and surface high pressure will build into the area tonight with clear skies as the coastal low moves east. This should make for good radiational cooling conditions. That said, the air mass building in from the west is moderating, and wind may not quite decouple and go calm until late tonight. A good inversion will keep ridge tops warmer than the valleys. MOS guidance for our Coop sites is colder than many of our obs sites. Therefore, expect a distinct urban/rural split between warmer and colder temps. Near lake areas will also be warm. Still, experience says when frost/freeze cases are marginal, they usually tilt toward the colder side. Therefore, will issue a Frost Advisory for all counties where the growing season is still active, knowing that some locations, possibly even more than half of some counties, will remain just above frosty temps. Lows around 5 degrees below normal. Expect a mild, sunny day with overall light winds Monday as high pressure and upper ridge remain in place. Increasing thicknesses and a dry atmosphere will lead to highs around 5 degrees above normal. While dew points are not forecast to be as low, the air mass is very dry. Warmer highs may lead very low RH values which could create a fire weather concern for NE GA. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... As of 100 PM Sunday: Upper ridge from the west will expand over the eastern third of the CONUS Monday night into Tuesday with surface high helping to control the overall weather pattern. Expect dry weather to be in store as thicknesses rise to 582-585 dm. This will push max temperatures Tuesday to 5-10 degrees above normal. A decent shortwave trough will quickly push north of the region and gradually breakdown the ridge Tuesday night into Wednesday with increasing clouds. Expect the surface high to slowly push off the southeast coast and bring a return flow back into the CFWA by Wednesday. Dry weather and above normal temperatures will continue through the end of the short-term. With good radiational cooling conditions Monday night, overnight lows will be near-normal under a starlit sky. Increasing clouds will keep overnight lows Tuesday slightly above normal. ~30 degree diurnal cycle will occur both Tuesday and Wednesday. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 210 PM Sunday: The extended period will primarily focus on a deep upper trough that will push into the region from the central CONUS starting Thursday. Model guidance are in consensus with the overall pattern. The ECMWF and GFS send a shortwave ahead of the upper trough with an attendant frontal boundary Thursday night into Friday. Low-level moisture will increase as the frontal system approaches the CFWA. The upper trough will take its time to push through the East Coast. Expect the trough axis will enter the region Friday night into Saturday, while the axis lifts east of the CFWA Saturday night into Sunday. A lot of uncertainty remains with the evolution, timing, and location of the dynamics associated with this vigorous system. As of now, guidance is trending towards a wetter solution and potentially washing the front out over the region. PoPs will be in store from Thursday night through Saturday for the new trend. An excessive rainfall and severe threat can't be ruled out with this setup. With extensive cloud cover and increasing PoPs, expect temperatures to moderate and gradually dip below normal by Saturday and remain that way through the end of the period. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... At KCLT and elsewhere: VFR and light winds will prevail. Mountain valley fog possible with a 20 percent chance of IFR or lower cigs/vsbys occurring at KAVL between 09Z and 14Z. Brief low end gusts possible between 14Z and 18Z, especially at KAVL. Outlook: VFR conds and light winds will prevail through Wednesday outside of isolated low cigs/vsbys focused across some mountain valleys mainly between 08Z and 14Z. A cold front will bring the chance of precipitation and widespread restrictions Thursday and Friday. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...Frost Advisory from midnight tonight to 9 AM EST Monday for GAZ018-026-028-029. NC...Frost Advisory from midnight tonight to 9 AM EST Monday for NCZ071-082-508-510. SC...Frost Advisory from midnight tonight to 9 AM EST Monday for SCZ004>014-019. && $$ SYNOPSIS...DEO NEAR TERM...Munroe/RWH SHORT TERM...CAC LONG TERM...CAC AVIATION...RWH