013017 Forecast

Mountain Area Forecast ( Jan 30-Feb 2 )

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ALERT For Strong SW Winds Developing Late Tonight Into Tuesday With 30 to 50+ MPH Gusts Along Middle To Upper Elevation Mountain Ridges-Plateaus ( the highest wind gusts generally in upper elevations ).

A strengthening pressure gradient will develop overnight into Tuesday morning as another clipper system passes across the Great Lakes.  Blowing snow could be a factor for high elevation routes such as State Route 619, 238, 237, 160 as well as others, passing through upper elevations of the High Knob Massif and across the Virginia-Kentucky border on Black Mountain.  The strongest low-level jet of roaring wind is expected to pass, with speeds diminishing somewhat, after 10:00 AM to Noon Tuesday.  Gusty conditions will continue through Tuesday Night at high elevations.  Caution is advised.

Overnight Into Tuesday Morning

Partly cloudy.  Becoming windy.  SW winds increasing to 15-25 mph, with higher gusts, along mountain ridges-plateaus below 2700 feet.  SW winds 20-30 mph, with higher gusts, along mountain ridges above 2700 feet.  Blowing snow at high elevations in the High Knob Massif.  Temperatures in the 20s to around 30 degrees, tending to rise into morning.  Wind chills in the single digits & 10s, rising into the 10s and 20s toward morning.

Tuesday Afternoon

Partly-mostly cloudy ( mid-high clouds ).  Windy.  SW-WSW winds 10-25 mph, with higher gusts.  Temperatures varying from upper 30s to lower 40s at highest elevations to lower-middle 50s ( warmest in downslope locations from Pound to Clintwood and Haysi-Grundy ).  Wind chills in the 20s and 30s ( coldest at highest elevations ).

Tuesday Night Into Wednesday Morning

 Partly to mostly cloudy.  W-NW winds 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges.  Temperatures varying from upper 10s to lower 20s in the coldest valleys to the middle-upper 30s.  Wind chills in the 20s and 30s along exposed mid-upper elevation ridges.

Wednesday Afternoon-Early Evening

Partly to mostly cloudy.  Variable winds generally less than 10 mph.  Small chance of a rain shower or a high elevation snow shower by the late afternoon or early evening.  Temps varying from upper 30s to lower 40s in upper elevations to the upper 40s to lower 50s.

Wednesday Night Into Thursday Morning

Partly-mostly cloudy.  Winds NW-N at 5-10 mph, with higher gusts, along middle-upper elevation mountain ridges.  Temperatures varying from low-mid 20s to the lower-middle 30s.  Wind chills dropping into the 10s on upper elevation ridges overnight into morning.

A progressively colder pattern Thursday into this weekend, with temperatures near to somewhat below average for this time of year, is being monitored ahead of a developing wave in the flow field.  A chance of frozen precipitation types will become possible by late Saturday into Superbowl Sunday.  Stay tuned for later updates.

Development of a major storm system is currently being outlooked for the February 7-9 period.  Strong winds and a significant temp spike & plunge will be possible with this storm system, along with moderate-heavy precipitation.  Stay tuned for later changes.


Weather Discussion ( Windy )

A majestic sunset in wake of the snow will now give way to increasing wind into Tuesday.  As so often is the case at this time of year, this will take the edge off warming at middle to upper elevations, especially, and across all locations in the Cumberland Mountains where winds are strong.

High Knob Massif Webcam – University Of Virginia’s College At Wise

Although temperatures climb some Tuesday-Wednesday, they will drop back Thursday into this weekend to produce a seasonally chilly pattern through the next week.  A couple of potentially important systems are upcoming during the next 5-10 days, but details remain to be worked out.

Preliminary Snowfall Report
( January 29-30 System )

Half A Foot of Snow Depth In High Chaparral of High Knob Massif – January 30, 2017

UVA-Wise NWS: 1.6″
( 2″ ground )

The Pines In Dungannon: 2.7″
( 2″ ground )

Clintwood 1 W: 2.8″
( 0.16″ NWS Rain Gauge )

Nora 4 SSE: 3.2″
( 0.19″ NWS Rain Gauge )

City of Norton WP: 4.0″
( 0.28″ NWS Rain Gauge / 3.0-3.5″ ground )

Head of Powell Valley: 4.5″
( 4″ ground )

High Chaparral of High Knob Massif: 6.5″
( 6″ ground )

Eagle Knob of High Knob Massif: 8.5″
( variable wind blown depths )

*Totals ideally include that which stuck-melted and/or settled during the event; although, all totals may not fully reflect this aspect which naturally creates variability in ground depths.  The addition of strong winds, like experienced at high elevations in the High Knob Massif, being a major factor in depth variations. 
Wicked Conditions On Eagle Knob of High Knob Massif – January 30, 2017

Conditions were simply wicked within upper elevations of the High Knob Massif with prolonged, persistently heavy snow during the overnight period.

Sample Hour From Black Mountain Mesonet At 4031 Feet Above MSL
*Air temperatures in the low-mid 10s combined with wind gusts of 30+ mph to generate below zero wind chills, with snow & blowing snow causing low visibility and large snow depth variations.
Snow Along U.S. 160 On Black Mountain Near The Wise-Harlan Border

While upslope snowfall was key, a snowstreak that was long-lived extended from Black Mountain to the Head of Powell Valley and across the main crest zone of the High Knob Massif ( 6″ to 12″+ of ground depth was common by Monday morning from High Chaparral to the peak area of High Knob, varying from near bare ground in places to a couple feet or more in wind blown drifts ).

Ground Depth Measured In High Chaparral By Darlene Fields – January 30, 2017
Joe & Darlene Fields have been measuring winter snowfall in the High Chaparral community of the High Knob Massif for more than 24 years ( elevation 3300 feet above mean sea level ).

Sharon Daniels verified that with around 4″ of snow at her lovely home sitting around 1850 feet above sea level in the Head of Powell Valley ( nearly 2400 vertical feet lower in elevation than the top of the massif ).

*The 8.5″ snowfall total for Eagle Knob is a best estimate, with the heaviest snow amounts across the head of Big Cherry Lake Basin which includes the peak of High Knob.
NASA Visible Image on January 30, 2017

While snow cover was widespread ( solid ) in nature from the High Knob Massif-Tennessee Valley Divide ( the white line I have on the above NASA Visible Image ) northwest to north, amounts varied with embedded squalls and streaks of snow squalls ( snowstreaks ) from 1-2″ on the low end upwards to 6-8″+ on the high end.

To the south and southeast of the solid white line, or the Tennessee Valley Divide & High Knob Massif, the snow was patchy in nature and dominated by bursts of snow in the squalls supported by very cold air aloft.  Here totals varied from a dusting to 1-2″ at most as this area lacked upslope and had to rely on atmospheric dynamics.

NASA Visible Image on January 30, 2017

Looking at this from a larger-scale perspective, streaks of snow can be seen across Kentucky to the northwest of the mountains amid otherwise bare ground, as once again with a lack of orographic lift snow accumulations were yet again relegated mostly to atmospheric dynamics ( cold air aloft & DPVA or Differential Positive Vorticity Advection which supported rising air and local streaks of snow ).

NASA Visible Image on January 30, 2017
*Many lingering clouds prevented this from being an ideal view, but a couple solid bands of snow cover can be seen along the two fronts of the Appalachians…the Cumberland-Allegheny toward the northwest and the Blue Ridge toward the southeast.  Initial lifting and convergence of air along the Cumberland-Allegheny ranges often making up for their lower elevation versus the Blue Ridge which both MODELS and most FORECASTERS neglect.