ALERT For Strong SW Winds Overnight Into Friday With Snow & Mixed Precip Developing.  Caution For Hazardous Surfaces Due To Recent Bitter Air.

Strong SW winds will continue to generate low wind chill values, especially at mid-upper elevations, as a warm front passes across the mountains.

The most favored zone for accumulating snow in this type of air flow setting is from the High Knob Massif-Tennessee Valley Divide southwest (i.e., from Norton and Wise southwest into Lee County).  However, there remains a question as to how much moisture will be available for locations southwest of Wise.

So, be aware of this potential and otherwise expect the potential for hazardous surface conditions across the area where any precipitation falls due to a prolonged period of very cold temperatures.  Caution is advised.

Former Alerts

ALERT For Bitterly Cold Temperatures Continues Today Into Thursday 

Bitterly cold air will grip the mountain landscape today into Thursday with dangerously low wind chills and temperatures for anyone not prepared.

ALERT For Brief Morning Burst Of Snow Impacting Parts Of The Mountain Area

A brief burst of heavy snow will be possible this morning along an Arctic cold front.  Given bitterly cold conditions and already frozen surfaces it will take very little snow to cause hazardous conditions. Accumulations of a dusting up to 1″ is expected.

Mountain Area Forecast ( Jan 30-31 )

Overnight Into Mid-Morning Wednesday

Becoming cloudy & bitterly cold.  Chance of flurries and snow showers by morning.  A brief, heavy snow burst possible.  Windy.  SW-W winds 10-25 mph with gusts over 40 mph.  Temperatures varying from the single digits to 10s (coldest highest elevations). Wind chills 10 above to -3 below zero in elevations below 2700 feet.  Wind Chills of 0 to -20 degrees below at elevations above 2700 feet.

Wednesday Afternoon

Sunny & bitterly cold.  Windy.  W-NW winds 10-20 mph with higher gusts.  Temperatures near steady or slowly falling in the 10s at middle-lower elevations and in the single digits at upper elevations along and northwest-north of the High Knob Massif-Tennessee Valley Divide.  Somewhat milder to the southeast into river valleys of the Clinch, Powell and Holston.  Wind chills mainly in the single digits above and below zero, except -10 to -25 below zero at highest elevations.

Wednesday Night Into Thursday Morning

Increasing mid-level clouds.  Bitter.  WSW-WNW winds decreasing to 5-10 mph with higher gusts on mid-upper elevation mountain ridges.  Temps from 8 degrees above zero to -8 degrees below zero, except locally colder if mid-level clouds dissipate or do not develop in locations with snow cover.

Updated_New Forecast

Overnight Into Mid-Morning Friday

Cloudy.  A chance of flurries or snow showers by morning.  Windy across mountain ridges and exposed plateaus.  SW to WSW winds 10-25 mph, with higher gusts.  Temperatures near steady or slowly rising within the 20s to lower 30s.  Wind chills in the 10s and 20s, except single digits at highest elevations.

Mid-Morning Friday Into The Afternoon

Cloudy with a chance of snow & mixed precipitation.  Accumulations from a dusting up to 2″ . Windy. SW winds 10-25 mph, with higher gusts, then decreasing by late in the afternoon.  Temperatures varying from upper 20s to lower 30s to the upper 30s to lower 40s, warmest in downslope locations of northern Wise and Dickenson counties and coldest in upslope areas of the High Knob Massif. 

   

Weather Discussion (Bitter_Little Snow)

Although a snow burst could catch you off-guard this morning if not prepared, the big story with this event will be bitter temperatures today and Thursday.

Joe & Darlene Fields measured only 1″ of snow in High Chaparral of the High Knob Massif during January 29, as the bulk of this system weakened and trended to the far south and southeast.

While a bit more snow depth is observed in portions of the highest elevations, lingering from previous snow, it is generally not more than 1-3″ when not counting drifts.  Puny for this massif, at this time of year.

Although the snow season still has a potentially long way to go, it has been down along the typically snow favored windward slopes with season-to-date totals varying from 63″ at Snowshoe to 54″ on High Knob.  The major missing ingredient, Great Lake moisture!

A period of rather dense, freezing fog which occurred after light snow was probably the most exciting and hazardous aspect in Wise during January 29.

However, given upstream air flow trajectories from mid-continent, without any Great Lake moisture tap, even this was limited in duration.

Running a backward air flow trajectory analysis into Wise County (above), it is easy to see why snow was limited with this system.  The source region was from the dry Canadian and Midwestern provinces.

Shift that trajectory east-northeast 300-350 miles and it would have been a different world, and the upslope locations could have been literally buried with snow from capture of Great Lake moisture.

Previous Discussion

The most brutal cold will hold along and north of the Ohio River, with the upper trough not being quite as deep as forecast last week.  Still air will be bitter and the potential for sub-zero temps remains likely for highest elevations and possible to likely across the area with clearing over snow cover.

Wind chill values will make it feel below zero across the area, with life threatening conditions if you are not prepared.  Extreme Caution is Advised.

Snowfall Forecast_Tuesday Thru Wednesday

A general 1″ to 2″ with locally higher amounts

Target snowfall 1.5″ for the elevation of Norton-Wise (+/-) 0.5″ error to suggest a 1″ to 2″ snowfall potential.  Locally higher amounts will be possible, especially at mid-upper elevations along the High Knob Massif-Tennessee Valley Divide and the Tennessee-North Carolina border.

Model trends through the weekend into Monday were to decrease snowfall amounts with this system.

More of a focus has been toward Mississippi-Alabama and as the front may slow a bit toward the union of borders with Virginia-Tennessee-North Carolina.

Clearly, the biggest impact will be with bitter air and low wind chill values Tuesday-Wednesday, with some of the lowest temperatures by late Wednesday into Thursday morning as winds decrease.