Sunday, April 5, 2020

Mid-Spring 2020_High Knob Massif


1:36 PM on 31 March 2020
Eagle Knob of High Knob Massif
Heavy, Wet Late Spring Fall Of Snow
Cody Blankenbecler Image - © All Rights Reserved

Heavy, wet snow fell at the summit level of the High Knob Massif during the transition from March into April (the period of change from 
early to middle Meteorological Spring).

12:30 PM on 1 April 2020
Eagle Knob of High Knob Massif
Riming And Snow Welcome Mid-Spring
Cody Blankenbecler Image - © All Rights Reserved

Around 4" fell beneath an upper-level low between sunset 31 March 
and sunrise on 1 April.  This was different from snow that fell during 
the daylight hours of 31 March when a Thermally Indirect Mesoscale Circulation (TIM) developed to enhance snowfall amounts.

Although snow water content was over 1.00" at the summit level, snow amounts diminished rapidly into lower elevations with little to no sticking below 3000 
to 3300 feet.

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

2019

January
6.14"

February
12.50"

March
5.93"

April
6.64"

May
6.75"

June
10.68"

July
10.77"

August
4.15"

Summer 2019
(Jun 1-Aug 31)
25.60"

September
0.63"

October
5.01"
( 5.89" to Midnight 31st )

November
5.20"
( 7.04" to Midnight 30th )

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 1-6 AM
1.94"
(2.28" on Eagle Knob of High Knob Massif)

Total Since January 1: 43.24"
[45.17"(M) on Eagle Knob of High Knob Massif]

Total Since December 1: 51.76"

Total Past 12-Months: 93.39" (M)

Total Past 15-Months: 118.46" (M)

(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).

*General 7.00" to 8.00" at upper elevations (above 3000 feet) with 5.96" at the City of Norton Water Plant (official NWS rain gauge located at approximately 2342 feet elevation).

**Third consecutive February to reach double-digit precipitation totals within upper elevations of the 
High Knob Massif.

Elevation 3139 feet
Big Cherry Dam of High Knob Massif
February Precipitation Totals (2008-2020)
Precipitation Totals Courtesy of Gary Hampton
and Wayne Browning

February 2018: 14.37"

February 2019: 12.50"

February 2020: 13.01"

10 April 2020
Overnight Burst of Snow
Computer Science-Mathematics Department

A burst of snow left a dusting in Wise, with a better covering on northern slopes in the High Knob Massif (far background above) into dawn on 10 April.

A Torrid Precipitation Pace

A torrid precipitation pace has been observed for five consecutive months, with total precipitation reaching 50.00" or more at upper elevations in the High Knob Massif since the beginning of December 2019.

2020 Precipitation Trend
High Knob Massif-Black Mountain Corridor

January-April precipitation amounts across the basin heads of Big Cherry Lake, High Knob Lake, and Norton Reservoirs have already exceeded the long-term annual mean for the state of Virginia.

2020 Precipitation Trend
Locations Immediately Downslope of the
High Knob Massif-Black Mountain Corridor

Although abundant, of course, a notable decrease in precipitation within the immediate wake zone of the High Knob Massif-Black Mountain corridor has been observed and is part of well documented longer-term climatology on mean SW air flow trajectories.

Focus On Research
(22 April 2020)

Big Cherry Basin
(An Appalachian Classic Cold Air Formation Basin)

Widespread In Northern Hardwoods
Halberd-leaved Yellow Violet (Viola hastata)
Wayne Browning Photograph - © All Rights Reserved

Halberd-leaved Yellow Violets were widespread in the northern hardwoods on my recent research hike into the Big Cherry Basin, where early spring conditions, at best, are on display with only a few maples and other species of trees beginning to bud.  Most new growth, which too remains limited, are vernal wildflowers.

Widespread In Northern Hardwoods
Halberd-leaved Yellow Violet (Viola hastata)
Wayne Browning Photograph - © All Rights Reserved

Early spring ephemeral wildflowers are hardy and can with-stand temperatures in the 10s and 20s as they hug the ground and barely poke up through leaves on the forest floor.

More often than not, these hardy beauties 
are covered by late season falls of snow.

Yellow Buckeye (Aesculus flava) featured the largest leaves of any trees observed in upper elevations, where they are typically the first to begin growing leaves every year.  They also grow downward in cold air drainages.  Most trees remain bare of leaves.

Dwarf Anemone 
(Anemone quinquefolia var. minima)
Wayne Browning Photograph - © All Rights Reserved

While Canada Mayflower (Maianthemum canadense
is coming up in spectacular profusion within portions 
of Big Cherry Lake Basin and High Knob Lake Basin, none are yet in bloom, with only the Dwarf Anemone observed blooming in Big Cherry Basin.

Since the COVID-19 horror story began I have worked hard on research, which is ongoing through Mississippi State University Graduate School.  If you are going to do research then ideally you want to choose something which either has not been done before or that is ongoing to which you may contribute knowledge.

Golden Ragwort (Packera spp.)
Wayne Browning Photograph - © All Rights Reserved

My current project is focused on development of nocturnal cold air pools, especially in upper elevation basins, with very little previous research having been done in the southern Appalachians (USA).

I have always been interested in cold air drainage and formation at night, with only the most classic basins, such as Burkes Garden in southwestern Virginia and Canaan Valley in northern West Virginia, being recognized by previous writing or research.

(Trout Lily is localized at upper elevations)
Yellow Trout Lily (Erythronium americanum)
Wayne Browning Photograph - © All Rights Reserved

A couple decades ago, I wrote a paper entitled "Domain Of The Cold Places" with a focus on southwestern Virginia that highlighted some 
of my initial research on these unique and 
climatically interesting places.

While frost and freeze data may be given, and various advisories-warnings issued at different times by NWS Forecast Office's, there are a few places embedded within the mountain landscape where frost and freezing conditions can develop during any month of the year.

Summer Minimums In Burkes Garden Basin
A 120+ Year Record (1898-2019)

Sub-freezing temperatures have been observed during each summer month in the record period, with 14.5% of summer seasons in Burkes Garden Basin having had a temperature at or below 32 °F (0 °C).  By comparison, 53.2% of summers had a temperature at or below 32 °F
(0 °C) in the higher latitude Canaan Valley Basin (Canaan Valley plus Canaan Valley 2 NWS cooperative sites).

Big Cherry Basin generates average mean minimums which are consistently lower than Burkes Garden, such that it would likely fall in between Burkes Garden and Canaan Valley with respect to longer-term summer frost and freezing conditions (longer-term being with respect to recent human history, which is hardly even a flicker in time compared to Appalachian natural history).

Cooling Heating-Curves In Different Basins
Autumn Example (2017)

A characteristic feature of basin climatology, more than that of draining valleys, is sharp cooling and warming curves.  Given the opportunity, regardless of general conditions, temperature will quickly fall (even if subsequently rising again) and create downward, nocturnal spikes and temperature fluctuations in the thermographic trace.

CLW (a cold air drainage near Clintwood), located in the more than 500 square mile (1295 square km) Russell Fork Basin, is a site well documented to have rapid diurnal temperature drops.  Yet, by comparison, it can not begin to keep pace with drops in Big Cherry Basin which become nearly vertical under the most ideal conditions.

Recent Example (Spring 2020)

By comparison, the April 1-22 period generated an average daily maximum of 66.0 °F and average daily minimum of 40.5 °F at TRI (Tri-Cities) in the Great Valley of northeastern Tennessee.

While nocturnal inversion formation has high frequency within Big Cherry Basin, conditions are often less than ideal and intermixed with settings featuring air mass advection and other small to large-scale disturbances (some of these have orographic origins and are forced by air flow 
across the massif or other mountains).

An Early Species In Bloom
Star Chickweed (Stellaria pubera)
Wayne Browning Photograph - © All Rights Reserved

A major motivation for Big Cherry Basin work is to develop a better understanding of how cold air pools can develop within an exceptionally wet environment, given most work related to cold air pool formation has been related to much drier and/or much less biologically diverse environments.

Dramatically Different Precipitation Regimes

The precipitation regime is so different between these two basins 
that plotting totals on the same graph makes them appear to be from different portions of the nation, not from within the same climate division of the Southwestern Mountains of Virginia.

Of particular interest to nocturnal cooling, the average annual precipitation received every year in Big Cherry Basin is higher (much higher) than the wettest year ever documented since record keeping began in 1896 within Burkes Garden Basin (*).

*You must pause to let that sink in, and realize the significance of what this actually implies with respect to climate and biodiversity across southwestern Virginia (knowing that some species prefer anomalous wetness, while others like it on the drier side).

This would suggest colder temperatures in Burkes Garden, given a much drier environment, but that is not the case and conditions are colder in 
Big Cherry Basin.

Mayapple (Podophyllum peltatum)
Wayne Browning Photograph - © All Rights Reserved

Mayapple is significantly bigger above 1200 meters (3937 feet) elevation in the High Knob Massif than it is within the cold air 
pooling area of Big Cherry Basin where it is yet to emerge or 
very small in size.

Canaan Valley Basin is significantly wetter than Burkes Garden Basin, but it is also significantly drier than Big Cherry Basin.  It is also much higher in latitude, being 383 km (238 air miles) northeast of Big Cherry Basin.

A puzzle to be solved, hopefully in coming years, 
is related to why has the lowest temperature ever documented in both Canaan Valley Basin and Burkes Garden Basin reached ''only'' 
-32.8 °C (-27 °F).

Lowest Annual Minimums In Burkes Garden Basin

The lowest MIN temperature observed during this 120-year plus 
record period in Burkes Garden reached -32.8 °C (-27 °F) in 1917.

1945-1996
Lowest Annual Minimums In Canaan Valley Basin

The lowest minimum temperature on record in Canaan Valley Basin also reached -32.8 °C in 1985, between the two NWS cooperative sites (record period from 1944-45 to present). 

1993-2019
Lowest Annual Minimums In Canaan Valley Basin


Ideal cooling conditions in wake of fresh snow 
on the morning of 20 February 2015 generated a minimum of -30.6 °C (-23 °F)  at Clintwood 1 W NWS cooperative (CLW), located 34 km northeast of Big Cherry Basin, such that it is nearly certain that Big Cherry Basin dropped to -35 °C (-31 °F) 
or lower, cold enough to have established a new 
all-time state record minimum for Virginia (**).

**No temperature recording was ongoing in Big Cherry Basin during 2015, but direct comparisons between CLW and Big Cherry Basin 
since recording started in 2016 supports the above statement, as does the much deeper snowpack (0.9 to 1.3 meters) present across the 
High Knob Massif in February 2015.

Rue-anemone (Thalictrum thalictroides)
Wayne Browning Photograph - © All Rights Reserved

Does this imply that Big Cherry Basin possesses a greater cooling potential with respect to extreme minima?  I think it does versus Burkes Garden and former Canaan Valley sites, but I believe that new frost pocket research ongoing in Canaan Valley will eventually achieve minimums lower than ever observed in Canaan before.

Both Canaan Valley Basin and Big Cherry Basin posses the potential to establish new, all-time state record minimums for West Virginia and Virginia, respectively, if temperature recording can continue through coming years.  It is only a matter of time and persistence.

1 February 2020 to 22 April 2020
Rim Temperature Comparison
Big Cherry Basin-Canaan Valley Basin

It is difficult to compare basins so widely separated by latitude within different climates, with the much wetter conditions and milder 850 MB temperatures (in the mean) engulfing Big Cherry Basin versus the drier and cooler 850 MB temperatures (in the mean) of Canaan Valley Basin.

Elevation is, by contrast, a common factor among all three of these Appalachian classics with the basin floor of Canaan, Big Cherry and Burkes Garden all being in the 945-975 meter 
(3100-3200 foot) range.

An ongoing correlation study is finding that 850 mb dewpoint depression possesses a strong positive association with basin floor temperature and inversion strength, so 850 mb conditions play an important role in basin floor temperatures.

Colder temperatures at 850 mb are, of course, associated with colder surface temperatures, irregardless of it being in an elevated mountain basin or a lowland valley.

Colder 850 MB temperatures, in particular, favor colder minimums in Canaan Valley Basin, with or without snow cover (snow cover being a prime factor for all of these upper elevation basins with respect to extreme minima), and this is observed 
in the mean (especially for coldest sites such as 
the northern frost pocket DY007 station).

1 February 2020 to 22 April 2020
Big Cherry Basin Floor Temperature
Adjusted To Canaan Valley Rim Temperature
Based upon 11,777 individual 10-minute observations
across the 4 locations used (47,108 total observations)

It should be clearly understood that these comparisons were made in order to better understand the control on cooling potential, not in any "competition" between classic Appalachian frost pocket basins.  They all possess the same "genetic'' composition (geologic DNA) and are all treasured places that must be protected and preserved for the benefit 
of all living things, including present and future human generations.

The cooling potential of Big Cherry Basin is significant, and if the 850 MB environment is adjusted to that of Canaan Valley Basin, taking 
rim temperatures to be essentially analogous to 
the 875-850 MB level (given both rims reach above 1200 meters), then basin floor temperatures of Big Cherry come into alignment with observed values of the northern frost pocket site in Canaan Valley (even slightly colder than it is, based upon only 
this single time interval comparison).

Why would Big Cherry Basin floor temperature be as 
cold or slightly colder than the Canaan Valley Basin 
floor under identical 850 MB conditions?

It might not be on any given night, but in the mean it would tend to be colder due to enhanced sheltering and decoupling from boundary layer flow versus the much larger and much more open Canaan Valley floor which appears to possess an inflection point between decoupling and recoupling that is lower than within Big Cherry Basin 
(in other words, a higher wind speed is required to force recoupling on the Big Cherry floor and vertical erosion 
of its cold air pool than in Canaan Valley).

Classic Cold Air Formation Basin
Big Cherry Lake Basin of High Knob Massif
Big Cherry Basin Floor - Cold Air Pooling Area
Wayne Browning Photograph - © All Rights Reserved

Finally, a nugget for thought.

The afternoon dewpoint can NOT be used as a predictor of the upcoming nocturnal minimum (even in absence 
of any moisture advection) within these classic cold air collecting basins (despite what is generally taught in the majority of meteorology classes).

3-8 April 2020
A Typical Recent Example
Various Disturbances With Varied Impacts On Basin Floor

This fact is also largely unrelated to any air flow drainage toward the basin floor, especially after low-level temperature inversion formation when downslope drainage of air flow appears to become a non-factor 
to basin floor temperature in Big Cherry (at least, with respect to higher slope air actually reaching its floor).

Gem-studded Puffball ( Lycoperdon perlatum )
Wayne Browning Photograph - © All Rights Reserved

Bottom Line for hikers, hunters, etc...if you plan to explore remote sections of Big Cherry Basin, Canaan Valley Basin or Burkes Garden Basin then you need to be prepared for two climates if near their basin floors (especially if conditions are clear and winds light).

A day-time climate, and their night-time climate with a near free-fall of temperature beginning prior to sunset into the evening when conditions can become cold quickly and catch those unprepared off-guard.

Wetland In Big Cherry Basin
Wayne Browning Photograph - © All Rights Reserved

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