My Forecast For Today ( February 17 )
ALERT For Freezing Fog At Middle-Upper Elevations Along & North of The High Knob Massif & Tennessee Valley Divide Overnight Into Wednesday Morning
Be cautious of slickness on decks-porches-steps and roadways at all locations where temperatures are freezing or below, and in the higher elevations, above 2500-3000 feet, where the most new snow accumulation occurred. Please slow down and be careful.
Steep creeks draining the High Knob Massif have had strong rises, so caution is advised when around these creeks. The run-off has slowed with colder temperatures and reduction in snow melt.
Overnight Into Wednesday Morning
Low clouds with freezing fog at middle-upper elevations, especially along & northward of the High Knob Massif and Tennessee Valley Divide. Light NW-N winds generally less than 10 mph. Temps dropping into the 20s to lower 30s.
This Morning Through This Afternoon
Damp & chilly. Low cloud bases lifting off of the middle elevations. WNW-NW winds 5-10 mph, with higher gusts possible. Chance of a localized PM shower of rain-mix in lower elevations and mix-snow at mid-higher elevations. Temperatures varying from the mid 20s to mid-upper 30s, coldest at the highest elevations.
Freezing fog will likely continue at highest elevations during the day, with the potential for cloud bases to drop again into middle elevations ( below 3000 feet ) into Wednesday evening.
Tonight Into Thursday Morning
Low clouds ( cloud bases may drop back on mid elevations ). Small chance of drizzle or flurries. Light NW to N winds. Temperatures widespread in the 20s ( dropping to around 20 degrees at the High Knob Massif summit level ).
An ALERT for strong SW winds may be needed by Friday as the pressure gradient increases along the Cumberland Mountains as warmer air is transported across the region.
Weather Discussion ( February 16-17 )
A wet snow fell across upper elevations, with mix in middle and lower elevations, during the early evening hours before a change to snow at all elevations by later Tuesday evening.
Abundant low-level moisture and light northerly winds have formed dense fog across middle to upper elevations, especially amid the favored lifting zone along and north of the High Knob Massif and Tennessee Valley Divide.
Tonight is again a perfect example to illustrate the temp error at Lonesome Pine Airport, with snow sticking to all above ground objects and other things while the reported air temperature was never below 34 degrees ( a 2 degree error, as I’ve noted many times in the past ).
Date and Time TEMP Dewpoint Precipitation
Meanwhile, the U.S. Forest Service station reported 32 degrees from around ( or a little before ) the 10:00 PM observation thru Midnight ( with very dense fog it is now equal to the dewpoint ) and should drop slowly into the overnight.
This type of fog is enhanced by rising air on northerly upslope even though winds tonight are light. It covers a very large area in Wise, northern Scott, and Dickenson counties but I can never seem to get that translated out beyond this area to officials responsible for issuing.
As air turns a little colder today we have a gloomy setting with abundant moisture in low-levels that will be hard to break up ( while some breaks can not be ruled out, models tend to increase afternoon-evening moisture enough to allow for at least a chance of a hit-miss shower of mix or drizzle at low elevations & snow at mid-upper elevations ).
The big picture does feature a relaxation in the recently harsh winter patter, but this will only be temporary, with cooling returning as soon as later Monday ( February 22 ).
The 00z February 17 run of the European 16 KM Model has again replicated a Miller A inland variant cyclone. The good news this remains 6-7 days out and changes will occur. The bad news will come if this type of storm is shown to verify! Stay tuned.
