... A cold front will cross the area today followed by cool and dry fall weather starting tonight and lingering through Monday. A warming trend is expected during mid-to-late week before another cold front possibly crosses the area by next weekend.
NEAR TERM /THROUGH TONIGHT/... As of 1010 AM: The latest SPC mesoanalysis indicated the cold front was pushing from the Blue Ridge mountains into the foothills, southward into the western Upstate of SC. Cold air advection was beginning in full force just behind the front, especially closer to the TN border. The forecast has a good depiction of associated light rain focused across the mountains, especially near the TN border and north of I-40 this morning with little if any adjustment needed with this update. The NAMnest is most robust in producing shower activity east of the mountains, especially near the I-77 corridor this afternoon. Slight chance to chance PoPs are likewise well placed. No significant hazards are expected through tonight, although will continue to monitor the gusty but likely below advisory winds behind the front and near freezing temperatures possible along the ridgetops late tonight.
Otherwise, the timing of the front thru most of the CWA will be more or less during the diurnal convective lull; most CAM runs continue to spit out very little QPF the remainder of the morning, though some do depict some weak cells firing in the SE half of the CWA as destabilization gets going again. The front looks likely to be just east of I-77 by early afternoon, and some models do show a sharp uptick in activity in that area and especially just to our east. Only an isolated to scattered precip mention is made for these areas; the western Upstate and most of NE GA still doesn't see enough fcst coverage to warrant even a slight-chance PoP. Any showers that do form look fleeting and QPF is not very remarkable. A rumble of thunder is not out of the question but appears unlikely. While 0-3km shear will be interesting at 30-35 kt as destabilization is occurring in the I-77 corridor, the lack of good dynamics indicates little to no severe threat, and the window for convection will be short at any rate.
Winds are already climbing ahead of the front, and gusting should begin by mid morning in many areas. Following frontal wind shift, brisk NW gusts should develop. Temps will be basically nondiurnal across the northwest half of the CWA, starting to fall by late morning in higher elevations, with an earlier than normal peak across the foothills and upper Piedmont. Quite the gradient today: while maxes will be generally 5 degrees or more below normal in the mountains, the lower Piedmont still looks to top out 5-7 above. Under CAA, gusts are likely to continue thru tonight across the mountain ridges and also in those portions of the foothills/Piedmont subject to gap winds. Looking at the range of guidance values, it still looks like gusts will top out below advisory criteria; this is backed up by pressure gradient being only about 4-5 mb across the mountains at peak during the afternoon and evening. Though mins tonight will be a drastic change compared to this morning, they actually will be only a couple degrees below normal in most areas. Guidance strongly supports fcst lows of mid-30s in most elevations above about 3000 feet, with a few isolated spots dropping to freezing (mostly above 5000 ft). The continuing wind makes frost unlikely even in relatively sheltered areas, and any freeze looks too spotty to warrant a Freeze Warning at this time. Will advise day shift to evaluate again for the afternoon package.
SHORT TERM /SUNDAY THROUGH MONDAY/... As of 120 am Saturday: With deep layered dry air expected to be atop the region for Sunday, abundant sunshine is on tap. Within the cool and dry llvl northerly flow, maximum temperatures will average around 5 deg F below climo in the Piedmont to about 10 degrees below normal in the mountains. With skies remaining clear Sunday night and winds decoupling in the mtn valleys, good radiational cooling conds are expected. Coupled with the cool airmass in place, there remains the possibility of frost development during the pre-dawn hours Monday across select NC mtn valleys. With another sunny day featured for Monday, maximum temperatures will begin the trend back to normal values.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 110 am Saturday: Upper heights atop the SE CONUS are progged to rise through Wednesday as sfc ridging lingers over the region. Dry wx will continue along with a warming trend as maximum temperatures climb to about a category above the mid-October normal. Global models remain in decent agreement with respect to the development of a moderately forced frontal band west of the mountains on Thursday and then shears it across the cwfa on Friday accompanied by what is looking to be a token amount of moisture at best. Sensible wx during the latter half of the period is still expected to be limited to just small shower chances associated with the cold fropa Thursday night and/or Friday. It is also likely that temperatures will remain above normal through the end of the period.