Saturday, May 9, 2020

Late Spring 2020_High Knob Massif

17 May 2020
High Knob Massif
Central Appalachian Northern Hardwoods
Slowly Emerging Spring In The High Country
Wayne Browning Photograph - © All Rights Reserved

The forest remains open at elevations above 3000 feet across the High Knob Massif, as of 17 May 2020, with trees varying from having sizable leaves to no leaves.  Reference the natural calendar for more information.

9 May 2020
Elevation 4196 Feet
Eagle Knob of High Knob Massif
Coating of Late Spring Snow Greets Sunrise
Cody Blankenbecler Image - © All Rights Reserved

The deepest snow was over leaves and grass, not gravel (as above), outside of some drifting which actually occurred along the lines of highest ridges and in high elevation gaps.

Rain changed to snow across the high country 
of the High Knob Massif into the evening and overnight hours of 8-9 May 2020.

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Air temperatures plunged to 19 degrees at the summit level, with wind chills dipping to around 0 degrees and below in northerly gusts. 

9 May 2020
Frosty Cold Morning In Wise
High Knob Massif Snow & Setting Moon 
Computer Science-Mathematics Department

The high country of the High Knob Massif and Mount Rogers-Whitetop stood out dramatically across western Virginia at sunrise on 9 May, with the most extensive covering of late spring snow and rime detected by GOES-16 imagery.

Islands In The Sky
High Knob Massif & Mount Rogers-Whitetop
GOES-16 Image At 1241 UTC on 9 May 2020

This marked the 8th event to produce some snow at highest elevations in the High Knob Massif since the beginning of April 2020 (total snowfall of more than 
13" during this mid-late spring period).

Painted Trillium Drooped By Snow
Courtesy of WCYB_Chime In

Photographer Becky Lagow captured a beautiful Painted Trillium drooped over in the morning snow.  These are yet to bloom within the cold air collecting basins (such as Big Cherry Basin) of the massif, and are a northern species of trillium restricted to mid-upper elevations 
of mainly western Virginia.


They grow within northern hardwood forests of the 
High Knob Massif, including fingers of north woods that follow cold air draining the high country through middle elevations into the lower elevation zone.

Pink Lady's-slipper Orchids
Courtesy of WCYB_Chime In

Pink Lady's-slipper Orchids are common 
but typically localized in their distribution.

Reference May 1989 Weather for an example of 
a similar late spring snow at this time during May, including a pattern that produced deadly flooding.

(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 1-24
7.99"
(6.48" on Eagle Knob of High Knob Massif)

Total Since January 1: 49.29"
[49.37"(M) on Eagle Knob of High Knob Massif]

Total Since December 1: 57.81"

Total Past 12-Months: 94.80" (M)

Total Past 15-Months: 119.87" (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.


The Natural Calendar

12 May 2020
Beautiful Red Peony
Wayne Browning Photograph - © All Rights Reserved

Whether it be cultivated, or natural, this 
time of year is wondrous in many ways.

Observed Return Dates
Wood Thrush (Hylocichla mustelina)

Take, as one example, the mean return of the Wood Thrush which is April 17 at the latitude of Clintwood, Virginia in the Cumberland Overthrust Block.

During 20 observed years, a range from 14-20 April 
has been the period during which it is nearly certain to return (3 day standard deviation from the mean-median return date of 17 April).

Extreme dates varying from April 11 to April 24, 
with 2005 and 2020 having the latest observed dates.

April 2005
850 MB Vector Wind Composite Anomaly

A common denominator between the two latest return dates is domination by northerly air flow during April 2005 and April 2020.  In other words, a ''headwind'' which any pilot knows can slow the trip down (and cause more fuel, in this case energy, to be used).  So, northerly air flow is not favored for migratory birds flying northward.

April 2020
850 MB Vector Wind Composite Anomaly

Northerly air flow acts to hinder northward migration with neotropical migrants, in particular, not wanting to expend more energy than necessary when returning to their summer breeding ground.  Much like a jet plane, southerly air flow is favored for northward migration 
via a nice "tailwind."

Most birders know that it is a well documented fact that many birds, especially the small Wood Warblers, will spend extra time in favored locations along the northern Gulf of Mexico following long flights across the Gulf when northerly air flow is dominating the eastern USA.  The birds stop, refuel, and rest for continued northward migration when conditions become favorable.

Slow Emergence Of Spring
In The High Country

17 May 2020
High Knob Massif
Central Appalachian Northern Hardwoods
Slowly Emerging Spring In The High Country
Wayne Browning Photograph - © All Rights Reserved

Mean temperatures in the 40s during the 1 April to 17 May period have held spring emergence back at upper elevations of the High Knob Massif, where minimums dipped into upper 10s as recently as May 9-10.

While some freeze damage has been observed on tree leaves, due 
to limited emergence (and the hardy nature of spring ephemeral wildflowers) freeze damage has not been as extensive as during 
major May freezes of recent decades (e.g., May 2005).

17 May 2020
Upper Elevations of High Knob Massif
Slowly Emerging Spring In Northern Hardwoods
Wayne Browning Photograph - © All Rights Reserved

Much like autumn, emergence of spring within central-southern Appalachian northern hardwoods is colorful and majestic.  Always a true blessing to experience 
every season. 

17 May 2020
Upper Elevations of High Knob Massif
Painted Trillium (Trillium undulatum)
Wayne Browning Photograph - © All Rights Reserved

A gorgeous Painted Trillium was blooming amid a huge patch of Canada Mayflower (Maianthemum canadense), most of which was not yet in bloom, during afternoon hours of 17 May.

17 May 2020
Upper Elevations of High Knob Massif
Canada Mayflower (Maianthemum canadense)
Wayne Browning Photograph - © All Rights Reserved

Canada Mayflower is most abundant in basins where nocturnal cold air formation occurs, and at highest elevations along wind swept ridges and meadows.  It is more abundant in the High Knob Massif than within any other area of the Cumberland Mountains, with its extent being under-estimated by famous field ecologist Lucy Braun (who did not survey 
the massif of High Knob).

Many acres are covered by the small but beautiful 
Canada Mayflower in upper elevations, a notable
species with a distinctly northern affinity.

It typically grows in association with Yellow Birch (Betula alleghaniensis) in the High Knob Massif, with many other northern species like Painted Trillium and a host of breeding avifauna.

A few of the bird species observed 
during this particular survey included:

Black-and-White Warbler
(Mniotilta varia)

Barred Owl
(Strix varia)

Blackburnian Warbler
(Setophaga fusca)

Black-throated Green Warbler
(Setophaga virens)

Blue-headed Vireo
(Vireo solitarius)

Chestnut-sided Warbler
(Setophaga pensylvanica)

Chimney Swift
(Chaetura pelagica)

Dark-eyed Junco
(Junco hyemalis)

Eastern Towhee
(Pipilo erythrophthalmus)

Eastern Wood Pewee
(Contopus virens)

Gray Catbird
(Dumetella carolinensis)

Hairy Woodpecker
(Leuconotopicus villosus)

Hooded Warbler
(Setophaga citrina)

Least Flycatcher
(Empidonax minimus)

Northern Raven
(Corvus corax)

Ovenbird
(Seiurus aurocapilla)

Pileated Woodpecker
(Dryocopus pileatus)

Rose-breasted Grosbeak
(Pheucticus ludovicianus)

Scarlet Tanager
(Piranga olivacea)

Veery Thrush
(Catharus fuscescens)

Wood Thursh
(Hylocichla mustelina)

Many other high country summer breeders are, or will soon, take their places amid the forest, such as Canada Warbler (Cardellina canadensis), Magnolia Warbler (Setophaga magnolia), Hermit Thrush (Catharus guttatus),
Red-breasted Nuthatch (Sitta canadensis) and many others.

17 May 2020
(Flash-fill Photograph)
Upper Elevations of High Knob Massif
Painted Trillium (Trillium undulatum)
Wayne Browning Photograph - © All Rights Reserved

Bad Season Expected 
For Northern Menace

Northern Black Flies Have Emerged
(Order Diptera in the Simuliidae Family)

A cloud of small, black flies were observed during 
17 May and at least one gave me a bite (despite wearing insect repellent) that again generated itching, swelling, and irritation for several days following the bite (*).  A bite, which is never initially felt since these flies inject an agent to prevent the host from feeling the bite, until 
its too late! 

*I forgot to spread Skin-So-Soft (reference below) on exposed skin (the bite occurred on the back of my hand), which I will make an effort NOT to forget again this season. 

I encountered these flies years ago and since have found they live generally at or above 3000 feet elevation in the High Knob Massif, and are analogous to flies which can plague folks around the Great Lakes, New England, and Canada.

Teena has written a great article describing them:
The Definitive Guide to New Hampshire Black Flies

Teena includes a natural, repellent recipe for Black Flies that I am sure will work.  I have had excellent luck with Maggie's Farm Natural Insect Repellent (including some of her listed ingredients) in combination with AVON's 
Skin-So-Soft spread on exposed skin.

The University of Wisconsin-Milwaukee has great information on these critters, including a photograph that looks very much like the ones observed in the 
high country of the High Knob Massif.

I have not yet tried to photograph them, as I am typically
documenting other things, but that may have to change.

The good news, these flies indicate the presence of clean, running water in lakes and streams.  The bad news, in a wet, mountainous habitat like the High Knob Massif they can reproduce longer and their season tends to be extended through mid-summer (instead of just late spring-early summer).

With a general 50.00" to 60.00" of precipitation having fallen across upper elevations of the High Knob Massif during the past 5 to 6 months, this is expected to be a banner season for northern black flies and possibly 
other menaces (to humans) of the deep forest.

An abundance of lakes and natural wetlands 
(the High Knob Massif contains the most mountain-top lakes of any mountain in the Appalachians), in addition to an array of whitewater creeks, makes the massif of High Knob an ideal location for this menace 
of the north woods!

17 May 2020
Upper Elevations of High Knob Massif
Slowly Emerging Spring In High Country
Wayne Browning Photograph - © All Rights Reserved

A horde of Eastern Chipmunks (Tamias Striatus), many with babies, were running throughout the woods, across roads, and everywhere else.

They can achieve exceptional abundance, it appears, across upper elevations in the High Knob Massif due 
in part to an abundance of food sources.

17 May 2020
Upper Elevations of High Knob Massif
Slowly Emerging Spring In Northern Hardwoods
Wayne Browning Photograph - © All Rights Reserved

17 May 2020
Upper Elevations of High Knob Massif
Approaching Sunset At 3900 Feet Above MSL
Wayne Browning Photograph - © All Rights Reserved

15 May 2020
Mature Sugar Maple (Acer saccharum)
Leaves In Lower Elevations To The North
Wayne Browning Photograph - © All Rights Reserved

This section is under construction.  Please check back.

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).

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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