... Canadian high pressure slowly builds into the region through Saturday. A weak cold front moves toward the area on Sunday then stalls over the area Monday and moves north as a warm front on Tuesday.
NEAR TERM /THROUGH THURSDAY/... As of 1250 PM EDT Wednesday: Snow show activity has mostly ended across the TN border counties, but can't rule out isolated flurries or light snow showers for NW flow upslope areas through the early afternoon.
The departing low pressure system will gradually drag the associated trough offshore by tonight. Decoupling of the boundary layer should occur at lower elevations, allowing temperatures to drop off fairly quickly tonight as skies also clear. This may support patchy frost development across the foothills into the northwest NC Piedmont with lows in the 30s to near 40 regionwide. Northwest flow aloft and near the surface will continue into Thursday, supporting breezy winds at times focused across the mountains. Sinking air associated with high pressure building into the region and downsloping flow off of the mountains will warm and dry the air mass into Thursday, supporting a rebound in temperatures, approaching normals of well into the 60s for most.
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... As of 130 PM EDT Wednesday: The short term picks up Thursday night in the middle of a quiet period, with a large upper low/trough exiting to our east and low-amplitude ridging moving in from the west. At the surface, weak high pressure centered over the Great Lakes will nose down into the area on Friday ad remain for Saturday. through the period, the muted upper ridge will move over the eastern CONUS, with heights expected to rise modestly both Friday and Saturday. Precip-free conditions will persist both days, though a slow moistening trend will begin on Saturday as low-level flow turns Srly. The only weather of concern will be some frost potential Thursday night/Friday morning, as lows will be just a few degrees below normal. Max temps Friday and Saturday will recover to near or just above normal levels as heights rise, with min temps recovering enough Friday night/Saturday morning that frost will no longer be a concern.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 200 PM EDT Wednesday: The medium range begins Saturday night a a pattern shift begins to occur. The upper ridge over the eastern CONUS will deamplify slightly, and a surface boundary will push towards the area as an upper shortwave moves over the area on Sunday. Deep moisture and surface forcing will both be rather anemic as the boundary passes Sunday afternoon, so though pops increase to chance level, rainfall coverage and QPF don't seem all that impressive into Sunday night.
Monday, the frontal boundary will lay over the area and some reinforcing Gulf moisture will arrive in the southeast as numerous weak shortwaves round the deamplified ridge over the southeast. Guidance currently ramps up pops on Monday afternoon which seems reasonable with diurnal heating, but precipitation still isn't well- forced, which should limit coverage and QPF through Monday night. More moisture will arrive Tuesday and Wednesday, increasing pops and supporting more widespread precip coverage. Upper ridging will support max temps 5-10 degrees above average through the middle of next week.