Partly cloudy ( some high clouds ). Patchy fog possible along major rivers. Winds becoming S-SW at generally less than 10 mph along mid elevation ridges and plateaus. SW to WSW winds 10-20 mph, with higher gusts, along upper elevation mountain ridges. Temperatures varying from the 10s to lower 20s in colder locations verses rising readings into upper 20s to lower 30s on exposed ridges at mid-upper elevations ( mostly above 2700 feet ). Wind chills in the 10s and 20s ( coldest at highest elevations ).
This Afternoon
Partly to mostly sunny. A period of mid-high altitude clouds. SSW-SW winds at 5-15 mph, with higher gusts, below 2700 feet. Winds SW-WSW 10-20 mph, with higher gusts, above 2700 feet. Temps varying from the lower 30s to the lower 40s ( coldest at highest elevations ), with mid 40s possible in downslope sites ( e.g., Pound, Clintwood ). Wind chills in 20s & 30s.
Tonight Into Friday Morning
Lowering cloud bases with flurries and snow showers developing overnight into morning. Turning blustery. Winds SW shifting WNW-NW at 10-20 mph, with higher gusts on middle to upper elevation ridges and plateaus. Temperatures dropping into upper 10s to upper 20s by sunrise to mid-morning. Wind chill factors in the single digits and teens ( coldest at highest elevations ).
Snowfall Forecast For Friday
Upslope Side of Mountains 0.5″ to 2.5″
Downslope Side of Mountains Dusting to 0.5″
Target snowfall of 1.0″ at Wise, ( +/- ) 0.5″ Error Potential. This implies 0.5-1.5″ possible in the Norton-Wise area. Extremes of a dusting up to 2-3″ will be possible across the area, with greatest snow amounts expected along upslope side of mountains with respect to WNW-NW air flow ( i.e., least snowfall to the ESE-SE from the High Knob Massif and Tennessee Valley Divide ).
Weather Discussion ( January 27-28 )
Reference my 012616 Forecast discussion section for a look at some interesting mountain wave clouds observed Wednesday.
Rime Coated Trees Along State Route 706 on Wednesday – January 27, 2016
The day began amid low clouds and a coating of rime along middle-upper elevation mountain ridges & plateaus, with widespread riming across the High Knob Massif as shown via an iPhone shot by my friend Darlene Fields on her way to work ( school nurse at Appalachia Elementary ).
High Knob Massif Webcam – University Of Virginia’s College At Wise
Wednesday ended with a gorgeous sunset featuring mountain wave clouds above the lingering snow.
NAM Model Temp & Wind Field Forecast At 7 AM Friday
Following a mix of sun and clouds today ( Thursday ) just enough moisture and lift will combine overnight into Friday morning for some snow to develop along the mountains.
Unless flow off Lake Michigan improves from what is being predicted by models now, limited moisture will only allow for light accumulations. It is so close; however, that a shift south by 50 air miles or so would increase snowfall significantly into the High Knob Massif area via more moisture from Lake Michigan & Lake Superior on NW flow.
NAM Model 500 MB Vorticity Forecast At 1 AM Friday – January 28
Flurries and snow showers will become possible late this evening into the early overnight of Friday as a upper air disturbance will be crossing the mountains.
A January Thaw which opens February continues on tap as a major winter storm develops and lifts northeast across the central USA, putting the southern Appalachians in its warm sector initially as February opens. Thunderstorms and strong gradient ( mountain wave ) winds are likely before cold air returns once again to shorten the thaw!
