Reference Late-Winter 2021_High Knob Massif as well as Mid-Winter 2021_High Knob Massif for a recap of recent conditions, and a 2020-2021 precipitation update.

For additional information on ice, please reference my 020921 Forecast page.

Previous ALERT-Discussions

Caution For Localized Freezing Conditions In Valleys Into Monday Night, With Rain And Gusty Winds Across Higher Elevations (Strong Wind Gusts At Upper Elevations).

Sheltered mountain hollows north of the High Knob Massif and Tennessee Valley Divide will be most at risk of having air temperatures near freezing (across northern Wise, Dickenson, and Buchanan counties on the Virginia side of the stateline) into Monday evening.

The official NWS temp at 5:00 PM is 34 degrees at Clintwood 1 W.

While localized temperatures around freezing will remain possible into Monday evening, the vertical depth of below freezing air has become very shallow.

Two things in the above image from UVA-Wise indicate important changes. First, cloud bases have finally lifted off middle elevations and, second, mountain waves on SSE-SSW winds have developed above the High Knob Massif. Both indicate enhanced vertical mixing that is finally eroding a low-level temperature inversion firmly in place for the past five days (5 long days of raw, cold, nasty conditions with icing).

Much colder air will begin to invade the mountain area toward Tuesday morning. Caution should be used for possible freezing of moisture remaining on roadways.

Miller A versus Miller B

The track of this next winter storm is trending farther east, with a current problem to be solved revolving around if it will be of a Miller A or Miller B type?

The current possibilities:

Miller A = Heavy snowfall event

Miller A (inland variant) = Crippling snowfall event

Miller B = Snow to rain back to snow

The basin meteorology behind a farther east trend is that a more expansive mass of cold air will cause the baroclinic zone to be pushed to the south and east to result in a much greater snowfall threat.

Numerous European and GFS model ensembles are showing the trend, while models like the NAM have not yet come into agreement and maintain more of a freezing rain-sleet-heavy rain threat.

Stay tuned for updates.

Weather Headlines

Mainly rain is expected by later Monday into Monday night when heavier rain arrives on strong SE-SW flow.

Freezing rain, with the potential of a major ice storm, remains likely for locations northwest of Pine Mountain across the foothills of eastern Kentucky into southwestern-western portions of West Virginia (especially in locations removed from downsloping SE-SW air flow).

Much colder air will flood the mountain area Tuesday with a chance of frozen precipitation early before drier air arrives during the day.

Temperatures during the daylight hours of Tuesday will vary from 10s at highest elevations to the 20s to near 30 degrees at lower elevations.

Because cold air advection (CAA) will occur across extensive, new snow cover west to northwest of the mountains, it will likely be stronger than most forecasts and forecast models predict (I have allowed for this with mainly 10s and 20s in locations along and NW of the Cumberland Front).

High Water-Flood Potential

While rises will occur on already elevated creeks, the flooding potential into Tuesday currently looks to be limited outside of typical poor drainage and low-lying locations where ponding of water is common.

Depending upon the amount of frozen versus rain, the flooding potential will be much higher with the second winter storm during 18-19 February 2021.

Second Winter Storm

There is an increasing snow potential with a second winter storm expected to impact the mountain area Thursday into Friday (other precipitation types will also occur, but snowfall totals are beginning to look higher for counties along the Virginia-Kentucky stateline).

Stay tuned for updates.

ALERT Continues For Freezing Fog Into Monday Morning – Especially In Locations Along & North Of The High Knob Massif-Tennessee Valley Divide (15 February 2021)

Freezing fog and areas of freezing drizzle will be widespread overnight into early Monday across lower-middle elevation mountain ridges and plateaus, as well as some windward upper elevations below 3600 feet.

The good news, deepening SE-SW flow will allow temperatures to rise and limit freezing rain potential when the main wave of precipitation arrives by later Monday into Monday night.