FXUS62 KGSP 040545 AFDGSP Area Forecast Discussion National Weather Service Greenville-Spartanburg SC 1245 AM EST Wed Dec 4 2024 .SYNOPSIS... Unseasonably cold air remains in place through tonight before a brief warm-up mid-week. The next cold front crosses our region Thursday dropping temperatures again to well below normal to start the weekend. A wetter weather pattern is possible by the middle of next week. && .NEAR TERM /THROUGH TODAY/... As of 1230 am Wednesday: The center of surface high pressure will settle over the southern Appalachians this morning, with resultant light winds, clear skies, and low dewpoints combining to yield min temps 15 to 20 degrees below normal across much of the area. Otherwise, broad upper troffing will move off the Atlantic Coast later today, allowing heights to modestly rebound over the Southeast. By the end of the near-term period early Thurs, the upper trof will amplify again over the Great Lakes with the trof axis remaining to our north. At the sfc, high pressure will steadily slide eastward today, and will be moving offshore as the period ends early Thurs. Meanwhile, a relatively dry cold front will approach the fcst area from the NW and will be moving over the NC mtns as the period ends. We should remain dry except for some slight-to-low chance PoPs over the NC mtns during the last few hrs of the period early Thu morning. Any QPF that does fall should be minimal, however profiles will likely be cold enough to produce a light wintry mix with minor accums above roughly 3500 ft. In addition, gradient winds from the SW will strengthen over the area this aftn/evening with gusts continuing to intensify thru the end of the period. This could result in Wind Advisory criteria gusts over portions of the NC mtn zones...with solid Advisory/possibly High Wind Warning criteria over parts of the northern NC mtns just beyond the near-term period on Thurs. As such, a High Wind Watch remains in effect for Avery County from late Wed thru Thurs aftn. The SWLY winds will bring warmer air from the Deep South, allowing temps to rebound a decent amount this afternoon, especially over the NC mtns, although highs should still remain a few deg below normal for early December. && .SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/... As of 145 PM Tuesday: A vigorous 500 mb shortwave will swing thru the Great Lakes Wednesday night. An associated cold front will drop SE thru the Ohio Valley and bring a 50-kt westerly 850 mb jet across the NC mountains overnight into Thursday. The winds start out west-southwesterly, and gradually veer to west-northwesterly by 12z Thu. So not an ideal direction for a mountain-wave high wind event, but strong CAA may allow for 50-60 mph gusts across the northern mountains above 3500 ft. Since most of Avery is above 3500 ft, will issue a High Wind Watch for Wednesday night thru Thursday aftn. Confidence is too low for anywhere else in the CWFA attm. Nevertheless, it will be windy during that period across most of the mountains. There will be a very brief shot of moisture with the front that may result in some snow showers along the TN border mainly Wednesday night. Moisture quickly dries out within the 850 mb flow Thursday morning. The front will bring temps back down well below normal in the mountains, but with downslope, temps will actually be a little warmer east of the mountains, but still below normal. Cold sfc high pressure quickly builds in Thursday night, with winds becoming light and skies clear. Lows expected to get into the teens across all the mountains and even into the NC Piedmont, low 20s elsewhere. Winds should become light enough to keep wind chills above advisory criteria (-5 F in the NC mountains), except for the highest peaks. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 200 PM Tuesday: The medium range starts out cold Friday morning, with the center of arctic high pressure settling over the Southeast. Highs Friday expected to 10-15 deg below normal, despite sunny skies. From there, the pattern will change with the eastern CONUS trough finally swinging out to the east and heights building in from the west. By Sunday, upper ridging will set up across the eastern CONUS with split flow in the West. The deterministic guidance still having some trouble agreeing on the individual shortwaves upstream of the ridge, but with potential southern stream energy ejecting out of the Southern Plains toward the end of the medium range. Gradually increasing return flow atop the forecast area will allow for a nice warming trend over the weekend, with slightly above normal temps by Monday. The latest NBM seems too quick in ramping up PoPs within the return flow regime. For now, have kept them mostly in the chc to low-end likely range starting Sunday night. By the onset of any mentionable PoPs temps are already getting too warm for any wintry precip concerns. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/... At KCLT and elsewhere: VFR through the period, with just some increasing mid and high-level clouds expected late today. Light or calm winds this morning will become SW at around 10 kts at most sites by early afternoon. Some gusts in the 15-20 kts range will be possible. SW winds are forecast to steadily increase Wed night, with some gusts of around 20 kts becoming likely after midnight. Outlook: A cold front will cross the area Thursday, bringing small precip chances and possible restrictions to the mtns Thu morning. Winds will become W/NW and increase Thu morning, with very gusty conditions possible, especially at KAVL and KHKY. Dry high pressure will return on Friday and linger thru Sunday. && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...High Wind Watch from this evening through Thursday afternoon for NCZ033. SC...None. && $$ SYNOPSIS...DEO NEAR TERM...JDL/JPT SHORT TERM...ARK LONG TERM...ARK AVIATION...JDL