011716 Forecast

My Forecast For Today ( January 17 )

*NOTE: Intense Snow Squalls With Whiteout Conditions For A Period Of Time Are Beginning To Push Across The Virginia-Kentucky Border And Will Impact The U.S. 23 Corridor From Pound Gap Into Norton-Wise-Clintwood Between Now And 10:30 PM

ALERT For Redevelopment Of Snow Showers Tonight With A Snow Burst Potential Along An Arctic Front Sunday Evening ( Around 9:00 PM For Norton-Wise Give Or Take An Hour ) – Followed by Plunging Temps And Wind Chills To Bitterly Cold Levels Into Monday

ALERT For Dangerously Cold Conditions Monday & Tuesday With Bitter Temperatures and Wind Chills Amid The Coldest Air Mass Since Last February

Once Air Temperatures Drop Below 20 degrees In Norton-Wise tonight, they may not rise above 20 degrees ( for any length of time ) until Wednesday.  They will certainly not rise above 20 degrees for those living on northern slopes.  Snow cover of 0.5-1″ or more will make conditions colder within locations having snow on the ground.

***Remember to dress warmly and to plan not to be outdoors longer than necessary.  Check on our elderly residents, take measures to protect pets ( e.g., horses, dogs, cats etc…need shelter from the cold & wind as well as ice free water ).  

Temperatures at the High Knob Lookout will drop below zero tonight, rise only into single digits Monday and go below zero again into Tuesday Morning.  Wind Chills will be EXTREME.  Travel & visitation to there is not recommended.

High country lakes will freeze over during this event, as will many ponds & slow running creeks.  Caution Is Advised as ice may not become thick enough to walk across safely.

Ice Thickness Guidelines From MN DNR 


Overnight Into Mid-Morning

A chance of snow developing during the predawn to sunrise period.  An interval of moderate snow possible.  Light NNE-NW winds at generally less than 10 mph.  Temps varying from upper 10s ( at highest elevations ) to the upper 20s.  Wind chills in the 10s & 20s, with some single digits at highest elevations.

Mid-Morning Through This Afternoon

Any snow tapering to flurries and ending.  Skies may briefly become partly-mostly cloudy ahead of an arctic  front by late.  Winds W to WNW at 5-15 mph, with higher gusts.  Temps varying from 20s to middle 30s ( warmest lee of mountains toward the Tri-Cities ).  Wind chills in the 10s and 20s ( coldest at highest elevations with single digits ).

Early Evening Into Monday Morning

Flurries and snow showers developing.  An evening burst of heavy snow ( whiteout conditions ) possible.  Winds WNW at 10 to 20 mph, with gusts to 30+ mph.  Turning bitterly cold with temperatures plunging to -2 to 12 above zero into the overnight-morning hours.  Wind chills from 5 above to -10 below zero across middle elevation ridges & plateaus, with -10 to -25 degree below zero wind chills above 3000 feet.

Snowfall Forecast ( Predawn Sunday-Predawn Monday )

General 1-2″ East of Rose Hill In Southwestern Virginia
General 0.5-1.5″ In Clinch, Powell, Holston River Valleys
Target Snowfall of 1.5″ in the Norton-Wise area ( +/- 1″ ) Error Potential.  This implies a potential from 0.5″ to 2.5″ and includes Sunday AM snow and Sunday Evening-Night snow ( with melting in between ).  Extremes of from a trace along and west of a Rose Hill to Pikeville line up to 3″ in the High Knob Massif ( from both events ) are possible.  Note that snow depths may never get as deep as total snowfall with afternoon melting of any AM snow ( especially southern exposed slopes & across lower elevations ).
While forecast models predict most places to have 1″ or LESS of snow, these graphics show the potential range when considering the current weather setting, terrain features & orographics, plus past climatology of similar such events.  Regardless of amounts, this is to be a relatively minor system but one that can cause roads to become slick and hazardous.  The bigger story, ultimately, will be dangerously cold wind chills and air temperatures arriving by later tonight into Monday ( when Arctic sunshine returns ).
Snowfall Totals For Entire Event ( AM and Tonight )
Snowfall Totals For Entire Event ( AM and Tonight )
Region With Arctic Front Snow Burst Potential
Generalized Snow Burst Potential Map
While not all locations will have a whiteout, these zones ( inside the RED ) have the greatest potential for a whiteout type of snow burst along the Arctic Front during Sunday Evening – especially locations along and northwest-north of the High Knob Massif.
Zone With Greatest Potential Of A Sunday Evening Whiteout
Zone With Greatest Potential Of A Sunday Evening Whiteout Burst


My Weather Discussion ( January 16-17 )

Afternoon Update

A period of morning snow deposited around 0.5″ or a little more of accumulation in the Norton-Wise area, with about the same in Clintwood ( 1″ on the ground ).

Morning snow, using time lapse video, appeared to stick but quickly melted down in the Great Valley and Tri-Cities.
High Knob Massif Webcam - University of Virginia's College At Wise
High Knob Massif Webcam – University of Virginia’s College At Wise
The High Knob Massif is looking majestic when it emerges from clouds with riming, above 3000 feet, for many miles.  After rising to lower 20s air temperatures have dropped into the upper 10s at summit levels of the High Knob Massif and Black Mountain.

The only change to my forecast in this update is to note that any brief break in clouds may be late ( or perhaps not at all ) as the Arctic Front cloud band has about caught up with clouds lingering in wake of the morning system.

NASA Visible Satellite and Doppler Overlay
NASA Visible Satellite and Doppler Overlay
Observe how the cloud break ( over central Kentucky above ) has just about filled in now ( below ) as it approaches the mountains.
NASA Visible Satellite
NASA Visible Satellite and Doppler Overlay

Observe also the snow showers developing along the Arctic Front to the west and northwest.  Those are the ones that I expect to bring a snow burst to the area this evening.

Current timing is between 7 PM and Midnight, centered around 9:00 PM for the Norton-Wise area ( give or take an hour ).  These will bring very bad road conditions with local whiteouts and a rapid covering of snow amid strong, gusty winds and falling temps.  Since yet again they do not have a good Great Lake connection, these will be brief in nature.
HRRR Model Future Doppler Forecast At 9:00 PM
HRRR Model Future Doppler Forecast At 9:00 PM


My Overnight Discussion

Air turned colder during Saturday with low clouds again trapped beneath an inversion layer.  Dense fog changed to freezing fog across upper elevations of the High Knob Massif where rime formation got underway.

Riming On Eagle Knob of High Knob Massif
Riming On Eagle Knob of High Knob Massif
While a little light snow coated roads amid the High Knob Massif in some upper elevation places, snowfall was more active to the north where several snowstreaks developed along Pine Mountain and extended across the Pound to Clintwood corridor of northern Wise County and Dickenson County.
Around 0.5" of Snow Accumulation In Clintwood at 6:59 PM
Around 0.5″ of Snow Accumulation In Clintwood at 6:59 PM Saturday

Visibility dropped to less than 1 mile with light to moderate snow around and just after sunset.  I measured 0.5″ at my elevation of 1560 feet ( so more accumulated amid these snowstreaks at elevations above 2000-3000 feet ).

Accumulation Following Light-Moderate Snowfall
Accumulation Following Light-Moderate Snow In Clintwood on Saturday
Reference the afternoon update in my 011616 Forecast discussion.

The productivity of these late afternoon snowstreaks is one reason I have gone above model output somewhat for this area, with such abundant low-level moisture lingering and poised to be precipitated out with any substantial lifting.

HRRR Model MSLP And Wind Streamline Forecast
HRRR Model MSLP And Wind Streamline Forecast – Weak NW Upslope Flow
The speed of this system goes against any greater amounts and may make it difficult to achieve predicted totals without a period of at least moderate snowfall ( note that forecasted snowfall also includes what comes along a vigorous Arctic Front this evening ).
HRRR Model Future Doppler Forecast For 8 AM
HRRR Model Future Doppler Forecast For 8 AM This Morning

The latest HRRR Model future Doppler forecast shows snow becoming widespread during the 5 AM to 8 AM period, but ending in the Norton-Wise area between 10-11 AM.  As with the previous rain system, there will tend to be a sharp cut off of snow along the western edge ( with LESS being the prime word for my snowfall graphic above to the west of Rose Hill in Lee County ).

Many places will likely have some melting of snow into this afternoon amid a break between this system and the bitter blast of air upstream.

 Bitter air pours into the mountain area tonight into Monday, and I will update that and the potential of a snow burst along the Arctic Front later today.

Travel Safe This Morning.