Thursday, March 13, 2014

Dramatic Weather Change & NW Upslope Snow


Elevation 2650 feet
March 13, 2014 at 6:52 AM
Long Ridge of Tennessee Valley Divide
Majestic Mountain Sunrise Through Falling Snow
Photograph by Wayne Riner - © All Rights Reserved.

Wayne Riner Photograph Thoughts...
"The morning sunrise came through snow showers which defused the sun's light.  Hopefully, the warm March sun will return springlike weather."


The warmest day since Autumn 2013 graced the highlands March 11 with widespread 60 to 70 degree temperatures, making single digits & 10s ( amid sub-zero wind chills ) extra dramatic into sunrise of March 13.

March 13, 2014
Elevation 3300 feet
High Chaparral of High Knob Massif
AM Snow Depth In High Chaparral Community
Photograph by Darlene Fields - © All Rights Reserved.

Joe & Darlene Fields, and family, have been measuring snow in the High Chaparral community for 22 years 
( 1992 to Present ).

This deck and picnic table above face into northerly winds,
where air does NOT have to cross the house to reach it in this
type of NW flow setting.

Roaring SW winds and rain showers, mixed with hail, during early afternoon hours of March 12 gave way to wind driven snow squalls and snowstreaks a few hours later as temperatures crashed!

March 13, 2014
Around 4" of Average Ground Depth
High Chaparral Community of High Knob Massif
Photograph by Darlene Fields - © All Rights Reserved.

Snow & blowing snow created blizzard-like conditions atop the High Knob Massif during evening and overnight hours of March 12-13, with VDOT snow plow operator Willie Mullins reporting 4" to 5"+ of snow depth on State Route 619.

Total fall at the summit level of the massif likely reached between 5-6" given sticking to roads was slower than on above ground objects and the northern slope woods 
( blowing & drifting making determination difficult ).

March 13, 2014 at 12:56 AM
Eagle Knob of High Knob Massif
Blizzard-like Conditions In Heavy Snow & Wind
Photograph by Steve Blankenbecler - © All Rights Reserved.

Snowfall Totals
NW Upslope Event
March 12-13, 2014

Elevation 2650 feet
Nora 4 SSE: 2.4"

Elevation 2342 feet
City of Norton WP: 2.6"

Elevation 1560 feet
Clintwood 1 W: 3.1"

Elevation 3300 feet
High Chaparral Community: 4.1"

( Main Crest Zone Above 3300 feet )
*Eagle Knob-High Knob-Camp Rock: 5"+

*Willie Mullins of East Stone Gap VDOT reported areas of
more than 5-6" of snow depth on Route 238 ( on the road itself )
to Eagle Knob and State Route 619 from High Knob to Camp Rock.

John Varner of East Stone Gap VDOT reported a general 2" on State Route 160 on the Wise County side of Black Mountain.  One reason for the difference was snowstreaks, with much of the massif northeast of South Fork Gorge and the lower Big Cherry Lake Basin being amid a prolonged streak of heavy, training snow squalls which mostly passed just NE to SW of the State Route 160
corridor on Black Mountain.

NASA Visible Image At 9:32 AM March 13, 2014

Streaks of heaviest snow being just southwest of downtown Norton, across the massif, and just northeast of the city through the UVA-Wise section of the Wise Plateau ( as illustrated later ).

Graphical Identification of Snowstreaks
NASA Visible Image At 9:32 AM March 13, 2014

The snowstreaks became most vigorous on the Virginia side of the stateline as air was forced across the High Knob Massif - Tennessee Valley Divide corridor ( with general weakening again to the southeast on downslope flow into the Great Valley ).


High Resolution Images
Snowstreaks Superimposed Upon NW Flow

The superimposition of snowstreaks upon the general NW Upslope Flow regime of this event was an important aspect that enhanced snow amounts along specific corridors with subsidence, or sinking, of air and less snow in between the snowstreaks.

March 13, 2014
Mid-Atlantic View
Beautiful Snowstreak Trajectories
NW Flow Snowfall & Snowstreaks
MODIS Today - University of Wisconsin-Madison

Snowstreaks are composed of training snow squalls.  
A snow squall is a burst of intense snow that tends to be much heavier than a snow shower.  When one squall after another travels along the same corridor they form plumes, or snowstreaks, analogous to those 
observed near the Great Lakes.

When superimposed upon upslope flow this combination can generate blizzard-like conditions, such as developed during March 12-13 in the High Knob Massif.

March 13, 2014
Mountain Empire View
Beautiful Snowstreak Trajectories
NW Flow Snowfall & Snowstreaks

A weakening snowstreak made it lee of the High Knob Massif into central Scott County, where it decorated higher elevations of Copper Ridge, before waning in Bristol, Virginia. 

More vigorous snowstreaks made it into the Great Valley of Washington County, Va., as air flowed by and over Brumley Mountain.

March 13, 2014
Overlay of Counties & Cities
NW Flow Snowfall & Snowstreaks

Many interesting things occurred during this event, only a few of which I have highlighted graphically.

March 13, 2014
Some Interesting Features
NW Flow Snowfall & Snowstreaks

A significant snowfall gradient occurred along the Powell Valley in Wise County, Va., from little snow at the southwest end of the valley around Big Stone Gap to significant snow near the Valley Head.  As highlighted below, this was due to a snowstreak corridor that became superimposed upon the NW Upslope Flow across the High Knob Massif.

A white area in the middle of Cumberland Gap National Historical Park denotes the location of the upper elevation Hensley Settlement, where open meadows show up nicely under a blanket of snow.

March 13, 2014
Some Interesting Features
NW Flow Snowfall & Snowstreaks

While not all NW Upslope Flow events generate snowstreaks, many do.  They occur under specific atmospheric conditions that must be resolved in advance ( as I was able to do before this event ).


High Knob Massif Webcam
Documentation of Dramatic Changes

Getting to the snow portion of this event was an adventure from predawn-sunrise showers and spring-like warmth to a ROARING early afternoon frontal passage of wind driven rains that were mixed with hail at higher elevations 
( a sign of things to come ).

NOTE: Webcam time has not yet been moved forward 
1-hour ( The correct time is noted above each image )

Click consecutively on images in viewer for motion
  ( Using Keyboard Arrow Keys May Be Easier )

March 12, 2014 at 12:49 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 12:50 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 12:51 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

Towering cumulus are observed 
through breaks in the low overcast

March 12, 2014 at 12:52 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 12:53 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 12:53 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 12:54 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 12:56 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:01 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:02 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:03 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:04 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:05 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:10 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:11 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:12 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:12 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

Observe hail beginning to fall 
as the frontal squall line arrives.

March 12, 2014 at 1:13 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:14 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:14 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:15 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:15 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:16 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:17 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

Observe the turbulent sky, trees swaying back & forth between frames, and a considerable amount of hail that remained mixed with driving rain 
( in coming minutes ) as the High Knob Massif becomes completely obscured.

March 12, 2014 at 1:18 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:19 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:20 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:22 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:23 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:23 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:24 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:24 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:25 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:26 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:27 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:27 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:29 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:30 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:31 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:32 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 1:36 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

Temperature changes amid this wild period are documented below for middle elevation locations 
in Wise and Dickenson counties.

March 12, 2014
Elevation 2141 feet
City of Norton Automated Weather Station
Courtesy of Weatherbug by Earth Networks

March 13, 2014
Elevation 2141 feet
City of Norton Automated Weather Station
Courtesy of Weatherbug by Earth Networks

Temperatures did not drop as low as the high-resolution NAM Model indicated from a couple days out in time, but did reach single digits atop the High Knob Massif and Black Mountain. 

March 12, 2014
Elevation 2650 feet
Nora 4 SSE Automated Weather Station
Courtesy of Wayne & Genevie Riner

March 13, 2014
Elevation 2650 feet
Nora 4 SSE Automated Weather Station
Courtesy of Wayne & Genevie Riner

While the first snowflakes and sleet started falling by mid-afternoon it was late afternoon into the night of March 12 when snow became intense 
amid squalls and snowstreaks.

[ The time on this CAM is correct ]

March 12, 2014 at 10:36 PM
The Main Campus of UVA-Wise
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 10:37 PM
The Main Campus of UVA-Wise
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 10:38 PM
The Main Campus of UVA-Wise
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 10:39 PM
The Main Campus of UVA-Wise
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 10:39 PM
The Main Campus of UVA-Wise
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 10:40 PM
The Main Campus of UVA-Wise
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 10:40 PM
The Main Campus of UVA-Wise
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 10:41 PM
The Main Campus of UVA-Wise
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 10:41 PM
The Main Campus of UVA-Wise
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

Time On This CAM Has Not Been Set Forward
( Time Indicated At Top Is Correct )

March 12, 2014 at 11:33 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:34 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:35 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:36 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

Observe the tarp blowing 
back & forth in the wind.

March 12, 2014 at 11:37 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:38 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:39 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

 March 12, 2014 at 11:40 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:41 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:42 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:43 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:44 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:45 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:46 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 12, 2014 at 11:47 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

These lovely scenes appeared as
morning clouds dissipated.

March 13, 2014 at 9:43 AM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 13, 2014 at 9:44 AM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 13, 2014 at 9:45 AM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 13, 2014 at 9:46 AM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 13, 2014 at 9:47 AM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 13, 2014 at 9:48 AM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 13, 2014 at 9:49 AM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

Skies cleared completely into mid-day as sun angles changed, allowing snow to become visible across more of the northern slopes.

March 13, 2014 at 11:30 AM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 13, 2014 at 11:36 AM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

March 13, 2014 at 12:07 PM
Looking Toward The High Knob Massif
University of Virginia's College At Wise
Courtesy of Computer Science-Mathematics Department

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