Mountain Area Forecast ( Feb 2-4 )
ALERT For Hazardous Conditions Developing Overnight Into The Predawn-Morning Hours Of Sunday ( February 4 )
ALERT For Strong SSE-SSW Winds Developing Along Mid-Upper Elevation Mountain Ridges Into Sunday
Another fast moving weather system will begin impacting the mountain region Saturday Night into Sunday Morning, with development of strong winds at mid-upper elevations and lowering cloud bases that will give way initially to snow.
Snow may become heavy before a transition to sleet and freezing rain and rain occurs during Sunday. A change back to snow, with additional accumulation, is expected Sunday Night into Monday morning as air once again turns bitterly cold. Numerous school schedule changes are expected to become necessary for Monday.
Friday Night Into Saturday Morning
Partly-mostly clear through the evening, then increasing high clouds overnight into morning. Bitterly cold. Light winds, becoming WSW-W at 5-10 mph, with higher gusts, along high mountain ridges. Temperatures in the single digits to low 10s, except below zero in colder mountain valleys at upper elevations of the High Knob Massif to Burkes Garden corridor. Sub-zero wind chills on high mountain ridges. Temps tending to rise along upper elevation mountain ridges overnight.
Mostly cloudy ( mid-high clouds ). SSE-SSW winds 5-10 mph, with higher gusts, below 2700 feet. Winds SSW-SW at 5-15 mph, with higher gusts, above 2700 feet. Temps varying from the 20s to near 30 degrees in upper elevations to the mid-upper 30s. Wind chills in the 10s & 20s along higher mountain ridges.
Snowfall Forecast – Two Different Periods
I ). Predawn-Morning Hours Of Sunday
A general 1″-2″ with locally higher amounts possible
This is the most difficult period to forecast since it has HUGE BUST potential, let that be stated CLEARLY with either little to no snow accumulation if warm air advection is fast enough to overcome evaporative cooling and other factors, or with significantly more snow should column cooling trend toward an isothermal vertical profile during the period of heaviest precipitation. I have gone in between these two scenarios, with 1″ to 2″ prior to a transition.
The High Knob Massif and Norton-Wise to Sandy Ridge area is of most concern with a potential to over-achieve, while lower elevations in Powell Valley and farther north into portions of northern Wise-Dickenson-Buchanan counties have the highest potential to under-achieve ( with little to no snow ), especially if winds can penetrate through a low-level inversion which will be trying to develop above the cold, still snow covered ( in many places ) ground.
II ). Sunday Night Into Monday Morning
A general 1″-2″ along the Upslope Side of the mountains with respect to NW flow ( i.e., along and west-northwest of the Cumberland-Allegheny Front ).
This is the easy period of the forecast with upslope snow showers developing as bitter cold air pours back into the mountains during Sunday Night into Monday. This will generate low density, fluffy snow with high snow to water ratios.
Saturday Night Into Sunday Morning
Lowering cloud bases. Becoming windy. Snow developing overnight into the morning, becoming mixed with sleet or changing to rain at lower elevations. Snow may be heavy. SSE-S winds 10-20 mph, with higher gusts, below 2700 feet. S-SW winds 20 to 30+ mph, with higher gusts, on mountain ridges above 2700 ft. Temperatures in the 20s to lower 30s. Wind chills in the 10s and 20s, except single digits possible at highest elevations.
Any snow or mixed precipitation changing to rain. Low clouds and areas of widespread dense fog. Nasty. Winds SSE-SW and shifting to W by late at 5-15 mph with higher gusts. Temperatures mainly in the 30s ( rising into the lower 40s in downslope locations if winds are able to penetrate a low-level inversion. Wind chill factors in the 20s to lower 30s.
Sunday Night Into Monday Morning
Turning bitter cold with rain changing to snow showers. Wind shifting NW at 10-20 mph, with higher gusts. Temps dropping into the 10s to around 20 degrees at low-middle elevations and into single digits at the highest elevations. Dense fog ( clouds ) with riming at upper elevations around and above 3300 feet. Wind chills plunging into the single digits above and below zero, except to colder than -10 F below zero at highest elevations.