... Dry high pressure will build in from the west tonight and settle over the area on Saturday. A cold front will bring widespread showers to the region late Saturday night through Sunday morning. High pressure returns Monday, then another cold front approaches the region around the middle of next week.
NEAR TERM /THROUGH SATURDAY/... As of 550 PM: NW flow behind earlier fropa could continue to produce an occasional sprinkle along the NC/TN border, but chance of accumulating rain looks near zero. The upslope layer will become increasingly shallow, so the remaining sprinkles should diminish by late evening. Breezy NW winds are noted across the mtns behind the departing front and look to remain breezy for a few more hours by the same token. Wind gusts look to range mostly from 20-30 mph during this time, with isolated higher gusts possible along the highest ridgetops. Sfc high pressure builds in from the west tonight leading to much drier conditions as well as gradually decreasing cloud cover; held on to abundant cirrus thru the evening in updated sky grids, but the clearing should then become evident. Temps updated to match. Lows tonight will be around 6-10 degrees cooler compared to last night, in the low to mid 30s across western NC, with upper 30s to lower 40s across the SC Upstate and northeast Georgia.
The sfc ridge will remain over the Carolinas on Saturday leading to continued dry conditions. High temps will be a few degrees warmer across the mtns and a few degrees cooler east of the mtns compared to today. Highs will still remain around 3-5 degrees above climo thanks to flow becoming southerly.
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 200 PM Friday...An upper low will track from TX to the mid-MS Valley Saturday night, then on thru the OH Valley Sunday. The low will open as a wave and take most of the better forcing north of the forecast area. However, the associated low pressure system will bring an occluded front with plenty of moisture thru the area early Sunday. Models are in good agreement on the timing and QPF. The front will be accompanied by a strong 850 mb jet that may get to 50-65 kt for a few hours early Sunday morning. Given strong WAA, the strongest gusts will likely be 4-5 kft in elevation. But an elevated-dependent wind advisory may be needed. A weak in-situ wedge will likely form, and keep any sbCAPE mainly south of the area. Although the NAM does show a few hundred J/kg of elevated CAPE, so we could hear a few rumbles of thunder as the rain moves thru. But any severe threat looks very low. The front should pass east of the area by midaftn Sunday, abruptly ending PoPs and even seeing some clearing skies in the west before sunset. Forecast soundings show a lingering inversion only a couple thousand ft AGL, but still may see breezy to windy conditions post-fropa, especially in the high terrain. Probably won't be strong enough for an advisory. Temps will be a few deg above normal, possibly getting into the lower 70s across the southern and eastern edges of the forecast area.
A secondary shortwave trough will cross the area Sunday night thru Monday, bringing a quick shot of low-level moisture to the NC mountains within a deep-layer westerly flow. A few isolated showers along the TN border may occur if the moisture gets deep enough, but overall, just a period of increased cloudiness is expected. Temps will be generally too warm for anything but rain until around daybreak Monday, where the highest peaks may approach 0 deg C. Lows will continue to be well above normal, with highs slightly cooler on Monday than Sunday's readings.
LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 230 PM Friday...An upper-level trough will dig across the Rockies Tuesday, while ridging builds along the East Coast. The trough will slowly move east Wednesday, bringing an associated cold front into our region. The 12z deterministic models are in decent agreement on the timing of the front, generally Wednesday aftn or evening. The front will have a good tap of Gulf moisture, and should spread a solid frontal band of precip much like the expected Sunday morning front. The upstream sfc high will push east of the area Tuesday, and well off the Mid-Atlantic Coast by Wednesday. So the models are not showing any CAD with this system, and there may be a little more potential for some sbCAPE into the Piedmont ahead of the front. Having said that, the models still keep the sbCAPE south and west of the area. The front will be fairly fast-moving, which should limit any excessive rain/flood threat. Temps will be a few deg above normal Tuesday, with increasing clouds and strong WAA keeping temps elevated Tuesday night thru Wednesday. So it looks like it will be too warm for any wintry precip type concerns with this system.
The front should be thru the area by early Thursday, with a little colder air mass building in and bring temps back down to slightly below normal Thursday and Friday. Once again, not expecting much of any overlap of moisture and temps cold enough for snow on the back side of the system. Neither the GFS nor the ECMWF have any NW flow snow.