Sunday, February 6, 2022

Late Winter 2022_High Knob Massif Area

 
5 February 2022
Eagle Knob of High Knob Massif
Fresh Snow And Upper Elevation Rime
Cody Blankenbecler Image © All Rights Reserved

A major storm system opened February 2022 with 
heavy rainfall that gave way to icing and light snow.  This marked the second month out of two this year 
to open with a major precipitation event.

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Steep creeks draining the high country of the High Knob Massif were continuing to recede but still ROARing as of 6 February 2022.

6 February 2022
Big Stony Creek of High Knob Massif

A combination of heavy rain and a melting snowpack generated a prolonged elevation of water levels, with 
13 consecutive hours at or above flood stage upstream of Fort Blackmore on Big Stony Creek.  A great gush 
of ROARing water was also observed along the 
South Fork of Powell River and other creeks.

Big Stony Creek of High Knob Massif

Snow melt drove a prolonged elevation of water levels to contrast with the more typical rapid rise and fall couplet associated with heavy rainfall events.

2 February 2022
High Knob Massif
High Country Snowpack Prior To Rain
Cody Blankenbecler Image © All Rights Reserved

A widespread, extensive snowpack covered the high country prior to heavy rain.  Sampling of snow found 0.40" to 2.00" of water content below 2500-3000 feet, with an estimated range of 2.00" to 4.00" above 3000 feet (with localized greater amounts).

2 February 2022
High Knob Massif
High Country Snowpack Prior To Rain
Cody Blankenbecler Image © All Rights Reserved


Precipitation Update

High Knob Massif
(Upper Elevations)

(Totals Listed By AM Measurement Format)
Monthly Total Precipitation
Big Cherry Lake Dam
(Elevation 3139 feet)

2019

January
6.14"

February
12.50"

Winter 2018-19
(1 Dec-29 Feb)
26.56"

March
5.93"

April
6.64"

May
6.75"

Spring 2019
(1 Mar-31 May)
19.32"

June
10.68"

July
10.77"

August
4.15"

Summer 2019
(1 Jun-31 Aug)
25.60"

September
0.63"

October
5.01"
( 5.89" to Midnight 31st )

November
5.20"
( 7.04" to Midnight 30th )

Autumn 2019
(1 Sep-31 Oct)
10.84"

December
8.52"

2019 Total: 82.92" (M)
 (January 1 to December 31 Period)


2020

*January
7.15"

**February
13.01"

Winter 2019-20
(1 Dec-29 Feb)
28.68"

March
9.55"
( 10.77" to Midnight 31st )

April
11.59"

May
8.73"
(6.90" on Eagle Knob of High Knob Massif)

Spring 2020
(1 Mar-31 May)
29.87"

June
7.48"

July
9.72"
(10.48" to Midnight 31st)

August
8.12"

Summer 2020
(1 Jun-31 Aug)
25.32"

September
6.21"

October 
7.06"

November 
1.96"
(Eagle Knob Snowfall: 0.5")

Autumn 2020
(1 Sep-31 Oct)
15.23"

December 
6.22"
(Eagle Knob Snowfall: 34.0")

2020 Total: 96.80" (M)
 (January 1 to December 31 Period)


2021

January
6.35"
***(Eagle Knob Snowfall: 34.0")

February
7.42"
(Eagle Knob Snowfall: 19.5")

Winter 2020-21
(1 Dec to 28 Feb)
19.99"
(21.70" on Eagle Knob)

March
10.82"
(11.14" to Midnight 31st)

April
2.53"
(Eagle Knob Snowfall: 2.5")

May
4.54"
(Eagle Knob Snowfall: Trace)

Spring 2021
(1 Mar-31 May)
17.89"

June
4.79"

July
5.55"

August
10.39"

Summer 2021
(1 June-31 August)
20.73"

September
5.82"

October
3.80"

November
2.23"
(Eagle Knob Snowfall: 1.5")
3 days with 1" or more depth

Autumn 2021
(1 Sep-30 Nov)
11.85"

December
4.63"
(Eagle Knob Snowfall: 1.0")
Several days with Trace depths

2021 Total: 68.87"
 (January 1 to December 31 Period)


2022

January
8.74"
(Eagle Knob Snowfall: 40.0")
29 days with 1" or more depth

1-19 February
5.71"

November 2019-October 2020: 102.34"

Autumn 2018 to Summer 2019: 91.21"

Autumn 2019 to Summer 2020: 94.44"

Autumn 2020 to Summer 2021: 73.84"

(M): Some missing moisture in undercatch and frozen precipitation, with partial corrections applied for the 24.4 meter (80 feet) tall dam structure where rain gauges are located.  Corrections are based upon 86-months of direct comparisons between NWS and IFLOWS at Big Cherry Dam (including occasional snow core-water content data).


Major Storm Event
2-5 February 2022

An array of orographic clouds signaled a major event and set the stage for enhanced precipitation amounts during 3-4 February along the crest and windward slopes of the High Knob Massif.

3 February 2022
Looking Toward High Knob Massif
Courtesy of Math & Computer Science Department

A review of 925-850 MB streamline flow reveals why significantly more rain fell along the Wise-Scott border area, with upsloping into orographic feeder clouds as observed in the above time lapse. 

Storm precipitation totals varied from 1.68" 
at Clintwood 1 W and 1.69" at Nora 4 SSE, on downsloping winds north of the High Knob Massif, 
to a general 3.50" to 4.00" across its high country.

With sinking air across its northern slopes during much of this event, the storm precipitation total was also much less at the typically wet City of Norton Water Plant where 1.96" were measured into morning hours of 5 February 2022.

925 MB Flow Field

18z 3 February 2022
925 MB Height & Wind Streamlines

00z 4 February 2022
925 MB Height & Wind Streamlines

06z 4 February 2022
925 MB Height & Wind Streamlines

12z 4 February 2022
925 MB Height & Wind Streamlines


850 MB Flow Field

18z 3 February 2022
850 MB Height & Wind Streamlines

00z 4 February 2022
850 MB Height & Wind Streamlines

06z 4 February 2022
850 MB Height & Wind Streamlines

12z 4 February 2022
850 MB Height & Wind Streamlines

Although this event did not produce big snow, 
it did generate great beauty with lower-middle elevation ice and upper elevation rime.

05 February 2022
The Tennessee Valley Divide
Icy Beauty In Wake Of Storm
Wayne Riner Photograph © All Rights Reserved

05 February 2022
The Tennessee Valley Divide
Icy Beauty In Wake Of Storm
Wayne Riner Photograph © All Rights Reserved

02 February 2022
Gorgeous Sunrise Prior To Storm
Wayne Riner Photograph © All Rights Reserved


High Knob Massif Climatology
Recent Snowpack Enhanced Run-Off Examples

3-6 February 2022

This example can be compared to one from January 2021 when snow melt and rainfall combined, with less total water content and 
a shorter enhanced period of elevated flow.

24-30 January 2021

A big snow melt driven run-off event was observed during March 2015, with much less total rain than during 3-4 February 2022.

10-12 March 2015

The big run-off event during March 2015 was the remaining remnant melt from a general 3-4 foot snowpack that developed during February 2015. 


There had been large precipitation differences across Virginia, as also observed recently and highlighted in the next section.


(Meteorological Winter 2021-22)
HUGE Precipitation Differences
Across Southwestern Virginia as of 5 February

An approximate total of 12.50" of precipitation in the Big Cherry Lake area of the High Knob Massif so far in 2022 (9.18" City of Norton Water Plant), and 17.13" since December 1, is simply dramatic compared to only 4.40" this year and 5.21" since the start of Meteorological Winter in Blacksburg. 

Blacksburg NWSO, Virginia

It would be much easier for personnel from 
the National Weather Service Office (NWSO) in Blacksburg to believe these High Knob Massif precipitation totals if they came and viewed the huge run-off, felt the ground shake and heard the awesome ROAR of steep creeks draining the high country, than it would be for me to believe that they had measured so little precipitation.

These limited totals, however, are not 
restricted to just the New River Valley.

Roanoke, Virginia

Lynchburg, Virginia

Danville, Virginia

Charolettsville, Virginia

Richmond, Virginia

Bluefield, West Virginia

Martinsburg, West Virginia

Actual differences are really much greater because rime drop and fog drip from trees across the high country of the High Knob Massif (that is very limited at low elevations) are not part of the 
Big Cherry Lake Basin totals.


Mountain Lee Wave
Rotor Development
(5 February 2022)

Although this video has a shake, I wanted to show it in order to illustrate how even in a benign setting with decreasing wind speed and moisture that a relatively obscure looking mountain lee wave cloud can still generate significant rotary motions along the High Knob Massif.

The shake is due to the way I captured the images 
in a 40-minute time interval with forward-reverse 
motion to isolate the subjects of interest.


Although the rotary circulation is a little difficult to 
see from this perspective, it is very distinct on close inspection with NW-WNW air flowing across the sprawling massif crest.


Birds Of Winter

Northern or Common Ravens (Corvus corax) have been nesting in the area of Eagle Knob for many years, with several pairs observed just prior to sunset on 10 February taking advantage of 
the flat top of a communications tower 
(elevation around 4300 feet). 

10 February 2022
Eagle Knob of High Knob Massif
Gathering Of Northern Ravens
Cody Blankenbecler Image © All Rights Reserved

State Route 619 can be seen running across the 
head of High Knob Lake basin near top of view.

Observe high-density snow lingering in wake of the 
major precipitation and run-off event that opened February.  Patches of bare ground near trees are due 
to enhanced melt from rain running down trunks. 

Northern Ravens are very intelligent, acrobatic, and tough to be able to live at this high elevation throughout the year where severe wind chills, orographic clouds, and driving precipitation 
events are common.

10 February 2022
Eagle Knob of High Knob Massif
Gathering Of Northern Ravens
Cody Blankenbecler Image © All Rights Reserved

For many years the classic, croaking calls of 
Ravens represented the wild high country as their population decreased dramatically.  Today they can be found along much of the Appalachian range.


Major Storm Event
High Wind-Dowpours-Snow
(17-18 February 2022)

This most recent storm event possessed two 
distinct phases associated with warm air and 
cold air advections (transport).

Lonesome Pine Airport In Wise
Warm Air Advection Phase

Lonesome Pine Airport In Wise
Cold Air Advection Phase

This is part of a wet pattern, looking to get much wetter before February ends, that has maintained relatively high base levels on mountain streams draining the high country.

Observed 2022 Stream Levels

18 February 2022
Looking Toward High Knob Lookout
Cody Blankenbecler Image © All Rights Reserved

Due to the relatively short-time period of saturation 
in sub-freezing air, rime deposition and accretion was mainly restricted to windward facing trees along main crestlines and initial windward slopes.

General 1" to 2" of snow, and majestic rime, developed across the high country of the great 
High Knob Massif as cold air caught low-level moisture into early hours of 18 February.

18 February 2022
Little Mountain Gap
High Knob Lake-Big Cherry Lake Basins
Cody Blankenbecler Image © All Rights Reserved

Snow showers and flurries continued over the massif during much of 18 February, with cloud breaks along the edge of the high country. 

18 February 2022
Landsat-Copernicus Visible Image

Dominate SSW-W flow in the 925-850 MB layer 
during Winter 2021-22 has to date biased much greater precipitation amounts to locations along and west to southwest of the Cumberland Front and High Knob Massif-Landform.

1 December 2021 to 17 February 2022
925 MB Vector Wind Composite Mean

1 December 2021 to 17 February 2022
850 MB Vector Wind Composite Mean

Extremes are exemplified by differences between Big Cherry Basin in the High Knob Massif and the New River Valley, with as much precipitation in less than 3 weeks in February at Big Cherry as measured since the start of December 2021 
in Blacksburg.

Big Cherry Dam Precipitation
Month To Date: 5.71
Since DEC 1: 19.08
Since JAN 1: 14.45

19 February 2022
Daily Climate Summary


Recap of January 2022

January was colder than average across much of the eastern USA, eastern Europe and western Asia.

January 2022
Northern Hemisphere
Temperature Anomaly Map

Locally, this unseasonably cold trend developed following a very warm start to the month.

January 2022
United States of America
Temperature Anomaly Map

A mean trough in the eastern USA and ridge over the western USA was opposite of the December 2021 pattern.

January 2022
Northern Hemisphere
500 MB Height Anomaly Map

Mean airflow during January was dominated by WNW trajectories, with an anomaly component from the NE at 925 MB and 850 MB.

925 MB 
Vector Wind Composite Mean

This type of low-level airflow favored heaviest precipitation falling across windward slopes of 
far southwestern Virginia.

925 MB
Vector Wind Composite Anomaly

Much less precipitation toward the east and southeast was a product of moisture extraction and downsloping of airflow crossing the western front range of the Appalachians, specifically the corridor known as the Cumberland-Allegheny Front.

850 MB
Vector Wind Composite Mean

Long-term airflow trajectories possessing mean westerly components, and anomaly flows with northern components, are a primary driver of the much wetter winter seasons observed across the High Knob Massif area versus farther east across the remainder of Virginia (*).

*All but far southwestern Virginia rests leeward of the eastern West Virginia highlands on W-NW-N airflow, with the Cumberland Front and High Knob Massif area being a southwestward continuation of this primary orographic lifting zone.

850 MB
Vector Wind Composite Anomaly

Sea level composite maps for January 2022 featured high pressure centered across the Intermountain Region of the western USA.

Composite Mean
Mean Sea Level Pressure

Composite Anomaly
Mean Sea Level Pressure