Monday, November 2, 2009

WETNESS Rules The High Knob Massif


Big Cherry Basin of the HKL Highcountry
Photograph by Wayne Browning - © All Rights Reserved.


October is climatologically the driest month of the year across the great High Knob Landform ( HKL ), and western front range of the Appalachians.

Not so during 2009, as October merely marked another notch in Mother Nature's wetness gun!

Its actually been more like a HOSE in the High Knob highcountry, where wetness has RULED the massif for the better portion of the past year.

My friend Gary Hampton, superintendent of the Big Stone Gap Water Plant, and his fine staff, have now measured more than 80.00" of total precipitation during the past 12-months at majestic Big Cherry Dam of the High Knob Massif.

Here's a Monthly Breakdown.

Big Cherry Dam of the High Knob Massif
Monthly Precipitation Totals
Elevation: 3120 feet

2008
November: 4.36"
December: 8.49"

2009
January: 9.23"
February: 4.36"
March: 5.51"
April: 5.40"
May: 7.07"
June: 5.44"
July: 8.42"
August: 7.08"
September: 9.09"
Oct 1-Nov 1: 6.00"

2009 Total: 67.60" ( M )
12-Month Total: 80.45" ( M )

There are numerous things interesting about this hand-measured precipitation data. 

First, its much more accurate than automated gage data but is significantly less than what has ACTUALLY fallen from the heavens, and accumulated at Big Cherry Dam and across its lofty basin ( water elevation of Big Cherry Lake being 3120 feet above mean sea level, at full pool, lowest in the main Big Cherry Basin ).

Although the Dam area is now monitored 24-hours per day, 7-days per week, and 365-days a year for security purposes, it is not possible for Gary and his staff to hand-measure precip every day.

During 2009, and the past 12-months, there has been at least 3.00" of evaporational losses from the rain gage between hand measurements at Big Cherry Dam ( this based upon evaporation losses observed under ideal conditions at my National Weather Service station, which I use as a "control" site ).

So in reality, more than 70.60" of precipitation would have been measured at Big Cherry Dam during 2009, and more than 83.50" during the past 12-months, if it had been possible to measure every day by hand. 

Thus, to be honest an ( M ), for missing moisture, must denote the above data set.

Majesty of Mixed-Hardwood Forest
Photograph by Wayne Browning - © All Rights Reserved.

So as farewell is bid to the glorious autumn color show of 2009, as so well documented by the professional quality photography of my good friend Roddy Addington, the above notation of missing moisture for the Big Cherry Dam observation site gets it on equal footing with other places that measure every day ONLY if the evaporational losses ( of approximately 3.00" ) are added. 

[ For Roddy's great photography reference the following: 

For mid-upper elevation measuring sites in the mountains, however, the ultimate reality is that even by hand measuring precipitation EVERY day there is still going to be a NET LOSS of recorded values due to wind induced rain gage undercatches.

I was blessed to learn about this aspect of wind induced gage losses in rain, and especially in frozen precipitation forms, by personal communication and instruction from Dr. Boris Sevruk. 

Boris is most likely the world expert on this aspect of climatological measuring and worked many years amid the rugged Alps of Switzerland to document and learn how winds play havoc with rain gages, their design, and placement.

Although Boris is now retired, he is nothing less than a legend in his field with an outstanding record of teaching, research, and contributions to many diverse climatological studies: http://www.iac.ethz.ch/people/sevruk/index

The way this world is today if you wish to truly learn something you should seek out the BEST of the BEST and, IF they are willing to teach, you will be blessed!  Boris WAS WILLING and I thank him so much.  I was blessed by the humble, sincere, and good hearted nature of Boris Sevruk. 

A truly RARE breed in this modern, ego-centered world, whom I will not soon forget ( I can only imagine what he may now do in his retirement! ).

Boris and others in the world have developed mathematical formulas that can be applied to gages based upon observed wind speeds, that clearly show the significance of precipitation gage undercatches.

Although I do not apply the formulas to my reported High Knob Massif sites, I have used them enough to know that what ever is measured and obtained, via adjustments for evaporational losses, will still result in totals that are well below what really falls.  This being especially true along exposed, convex crestlines, and other open sites where winds are either turbulent, rising, strong, and/or all of the above!

Eagle Knob of High Knob Massif
Fiery Maple At Nearly 4200 Feet Elevation
Photograph by Wayne Browning - © All Rights Reserved.

Beautiful autumn colorations, such as above, can be short-lived on the Eagle Knob of High Knob where my weather station sits at 4178 feet above mean sea level.  Although not the highest peak in Virginia, the location is one that finds air almost always rising and in turbulent motion.

A placement of rain gages in MANY different locations generates varying totals, which Boris noted makes it especially hard to obtain accurate measurements of true precipitation falls.

That the above is true becomes SO VERY OBVIOUS when winter settles into the highcountry!

High Knob Massif Crest Zone
Eagle Knob of High Knob Massif Wind Effects
Steve Blankenbecler Image - © All Rights Reserved.

The above image, courtesy of my friend Steve Blankenbecler, illustrates how northerly winds blowing across the summit of Eagle Knob have swirled the snow with vortical suction motions into convergent rows, piles, and deep zones, all the while sweeping the ground bare within adjacent locations.

Although the above setting was impacted by the communication tower and chain-link enclosure, the same type of effects occur around trees and other natural features along the crestlines.

During many past snow events I have recorded for my records that snow depths along the crestlines varied, "from bare ground to feet in drifts."  While that might sound a bit crazy, it is indeed the reality, true, and honest!

What may not appear to be obvious, from the above, is that highcountry winds impact RAIN in much the same way.  It's just that one can not see how the rain accumulates, drifts, and blows around like snow!! 

While it is true, that rain is not perturbed as MUCH as snow, or frozen forms, it IS perturbed as anyone can prove by placing small containers near to the ground in different locations.  When winds howl, and rains fall, each container will almost certainly collect varied amounts for the different locations.  Yes, much like snow, the rain blows, drifts and accumulates much more in some places than others.

High Knob Massif Crest Zone
Endemic Southern Appalachian Northern Hardwoods
Photograph by Wayne Browning - © All Rights Reserved.

When looking upon the richly varied forests of the High Knob highcountry, as illustrated by the vast array of colorful species above, one may not think about such things as drifting rains and snows!  And may not think about how they have played important roles in establishing all the ecological niches that are exploited by more species, from beneath the forest floor to its tippy-top, than ANYONE today even knows are there!

But in fact, the situation is SO MUCH more complex, since up in the highcountry wind speeds nearly always INCREASE with the onset and continuation of precipitation.  For valley dwellers, of which the majority are, you may know that wind speeds typically decrease after precipitation begins in non-convective settings.

For here, I am mainly talking about the orographic forcing season, from late autumn through spring, when large-scale storm systems develop pressure gradients that generate WINDS to push against the topogrpahy.

It is during the orographic forcing season that the truly great ones, like the High Knob Massif, Mount Rogers, Roan, Mitchell, Mount LeConte, Mount Porte Crayon, and numerous others
FLEX their mountain MUSCLES.

In places like the Big Cherry Basin it is denoted by an UP-spike in their measured precipitation amounts during the forcing season relative to other locations not impacted by strong orographics, or subjected to mean negative forcing ( i.e., subsidence or sinking with downslope trajectories ).

In fact, for measurement purposes, high basins and coves tucked away amid the highcountry are the BEST places to set up precipitation measuring sites in upper elevations. 

Southern Appalachian Mixed-Mesophytic Cove Forest
Photograph by Wayne Browning - © All Rights Reserved.

The many basins within the sprawling High Knob Massif offer unique opportunities, as do locations like the relatively sheltered cove tucked amid the lofty north slope of Mount LeConte in the Great Smokies ( perhaps the BEST measuring site for such a HIGH elevation in the Appalachians ).

The higher convex crestlines are therefore NOT where one would choose the best places for measuring precipitation, since in order to do even partially good it requires changing rain gage locations with shifting wind directions ( e.g., the southeast side of the crest for a NW wind, the northwest side of the crest for a SE wind, the northeast side of the crest for a SW wind, the southwest side of the crest for a NE wind ).

The above is not currently possible, but tilting rain gages that tip with changing wind directions and speeds are an experimental possibility for improvement toward what I just described. 

Not a solution, since winds rise upwards, often at accelerated speeds across crestlines, such that many precipitation elements are actually carried completely across and fall leeward onto high slopes, into high basins, or simply evaporate away with sinking, or subsidence, along narrow crested ridges.


The Lifting Zone

Nestled against northern slopes of the High Knob Massif, the remnant highcountry of the HKL, is the lovely City of Norton.

The wettest town or city in Virginia as verified by data scans of ALL available resources.

Norton is proving that once again during 2009, and the past 12-months, with enhanced precipitation amounts via a general mean of rising air amid the lifting zone created by the sprawling massif.

A most interesting situation, given periods of significant sinking, or downsloping, which also subtracts precipitation from the city on south to southeast air flow trajectories ( at least under typical conditions, as there are some notable exceptions ).

My friends, Superintendent Tommy Roberts and his great staff, diligently measure precipitation by hand every day just like clock work at Norton WP.

Here's a Monthly Breakdown.

City of Norton Water Plant
Elevation: 2342 feet

2008
November: 3.68"
December: 8.58"

2009
January: 7.34"
February: 3.27"
March: 5.24"
April: 5.13"
May: 9.72"
June: 7.95"
July: 5.46"
August: 5.19"
September: 6.08"
Oct 1-Nov1: 4.68"

2009 Total: 60.06"
12-Month Total: 72.32"

A comparison between the Big Cherry Dam and Norton WP data sets reveals some interesting variations.

Much more rainfall was measured in Norton ( 5.16" more ) during May-June than at Big Cherry Dam, while much more rain fell at Big Cherry Dam during July-September ( 7.86" more ) than in Norton. 

These differences being concentrated mostly during the rather chaotic convective season, with variations in the formation and propagation of showers and thunderstorms along the massif.

At some location, or locations, in between these two data points ( and they are only point measurements ) there was likely more total rainfall than measured in either rain gage, as well as less, to generate a greater spread in "warm season" rainfall than suggested by just the Big Cherry and Norton stations.

In general, the most steady difference can be seen during the orographic forcing season of November-April, ( sometimes this can include May and/or October ), with the Big Cherry Dam measuring point consistently receiving more precipitation each month than the City of Norton. 

This despite the greater evaporative and wind induced rain gage losses at the higher elevation Big Cherry site ( i.e., the difference between Big Cherry Dam and Norton was greater than indicated by the rain gages since the gage at Big Cherry had loss of moisture due to evaporation between hand measurements and greater forced losses due to stronger winds blowing across its opening ).


Powell Valley of the High Knob Massif

Anyone from this area, or traveling through the region along our famous Country Music Highway ( U.S. 23 ), knows that the Little Stone Mountain Gap passage in the High Knob Massif often marks a major weather change zone.

Amid "quiet" times it may "only" be marked by such scenes as below, which was beautifully captured in a series of pictures by Ron Flanary during early October.

Lingering Inversion - Powell Valley of High Knob Massif
Photograph by Ron Flanary - © All Rights Reserved.

My good friends Elizabeth & Addison Stallard live beneath the fog layer above, within the majestic Head of Powell Valley, and have been keeping weather records since the 1970's.

These "youngsters" have documented the good, the bad, and the ugliest of weather conditions, and deserve no less than a GOLD metal for their efforts over all these many years.

During 2009, and the past 12-months, they have measured the following monthly totals with nary a missing day! 

Head of Powell Valley of High Knob Massif
Elevation: 1945 feet

2008
November: 3.30"
December: 7.50"

2009
January: 7.10"
February: 3.06"
March: 4.84"
April: 4.72"
May: 8.37"
June: 6.37"
July: 5.63"
August: 5.27"
September: 6.33"
Oct 1-Nov 1: 4.31"

2009 Total: 56.00"
12-Month Total: 66.80" 

Thanks to Elizabeth & Addison Stallard we have an insight into the local climate that simply would not exist without their exemplary records!

Measuring every day near the other end of Powell Valley, amid the great South Fork Gorge opening at the Big Stone Gap Water Plant, my friend Gary Hampton reports a little more than the Valley Head, with just over 56.00" during 2009 and nearly 68.50" in the past 12-months.

November 4, 2009
Upper Tennessee River Basin
Looking to South Fork Gorge of Powell River Basin
Majestic Morning Light In Powell Valley of HKL
Photograph by Roddy Addington - © All Rights Reserved.

[ Majestic morning light illuminating a cornfield at the end of the growing season was beautifully captured by Roddy Addington early on November 4.  Rugged mountain walls rising upward in the background guard the opening of South Fork Gorge ].

The highcountry of the Big Cherry Basin, spreading out above Powell Valley, has received more than a foot ( 12-14" ) of measurable precipitation beyond that observed amid the beautiful Valley during the past 12-months ( MUCH more when allowing for evaporation losses, of at least 3.00", and wind generated rain gage undercatches in both rain & snow ).

Of course, that is just PRIMARY precpitation!

When factoring in FOG drip from trees and the gorgeous but very important RIME deposition upon trees, the addition of SECONDARY moisture sources across the High Knob highcountry has truly generated a MAJOR bonus of moisture which is FAR greater than that endured by residents living amid the rugged mountain walls of Powell Valley.

[ For STUNNING Roddy Addington photography and to obtain additional information about RIME please reference:  Introduction To RIME In The High Knob Massif ].

This is WHY the High Knob Massif is a true WATER CAPTURING WONDER for this latitude in Virginia and the Appalachians.  The numbers simply DO NOT lie and reveal a great many things which are key to the vast biodiversity & karstification of this truly incredible and ancient landscape of the HKL.

It's time we all learn!


Current Wetness Ranking Within The HKL

Good, consistent, weather records reveal that 2009 and the past 12-months have been wet, but NOT nearly as moist as the wettest documented since just the late 1970s-early 1980s ( a relative, minute flicker amid the vastness of time ).

The wettest 12-month period on record in the city of Norton had more than 80.00" of total precipitation during the 1993-94 period ( 79.29" in the gage, but with notable moisture loss during the rather harsh winter in deep snowfalls that the smaller rain gage, used at that time, could not hold ).

This suggests that the 1993-94 period had 8.00-10.00"+ of precipitation above what has been observed so far during the past 12-months, with MAX totals of between 90.00" to 100.00" within the High Knob Massif verses the 80.00" to 90.00" max amounts attained since November 2008.  

IF November and December of 2009 are VERY wet, this year has at least a shot at becoming the wettest locally observed during this relatively short record period ( of 32-years ).  However, the odds are against it being that WET, unless this November can pull it out, since the wetness of December 2008 will drop out of the 12-month interval after December 2009 begins.  Only time will tell.

High Knob Massif
Upper Tennessee River Basin
Big Stony Creek of Clinch River Basin
Mountain Fork Backcountry of Big Stony Creek
Photograph by Otis Ward - © All Rights Reserved.

[ My friends Otis & Nancy Ward contribute much more than beautiful pictures, as they have also measured precipitation in the Robinson Knob community of the High Knob Massif for a number of years.  The driest month observed there during the past 12 was February 2009, with 4.05" of precipitation.  They were among the original founders of The Clinch Coalition ].


Outside The Lifting Zone 

The true significance of the High Knob Massif precipitation regime can be seen by an inspection of monthly totals from outside of its orographically forced lifting zone, where air flow trajectories are often impacted by downsloping leeward of its highcountry.

That such impacts should be felt is not surprising, given that if one sat the southwestern base of the High Knob Massif over the town of Wise you would have to drive all the way northeast to the town of Clintwood in order to reach its other side.  Just think about how many typical ridges and hills are passed along that distance!

Likewise, if the base of the mountains on the right side of Roddy's gorgeous cornfield photograph were placed over Red Onion Mountain, on the Wise-Dickenson border, the other side of the massif would reach all the way across to the Dickenson-Buchanan border ( along a W-E trajectory ).

When standing at Powell Valley Overlook in Little Stone Mountain Gap, the distance across to the other side of the massif along a NNW-SSE trajectory to Hanging Rock Recreation Area in northeastern Scott County is analogous to traveling from Elk Garden in Russell County to Glade Spring in Washington County.

The distance between the north base of the High Knob Massif at Ramsey, in Wise County, and it's southern base at Ka, on Big Stony Creek in Scott County, is the same as traveling from downtown Lebanon in Russell County to south of the North Fork of the Holston River in Washington County.

We are NOT dealing with any typical mountain here, as the gifted, talented, and sweet Gladys Stallard recognized so many years ago in her wonderful wildflower journeys and nature writings with award winning author, columnist, and dear companion
Gaynelle Malesky.

[ Beloved Gaynelle S. Malesky passed in September 2003 at the age of 92 and leaves an impressive legacy of poems and columns.  Gaynelle & Gladys wrote nature columns in the Coalfield Progress newspaper for more than 30 years and were the first writers, whom I remember, to distinctly recognize the unique size, topography, and nature of what
they knew as the great High Knob Mountain mass ].     

When adding the extended landform of High Knob, with its rugged northwestern mountain flank reaching southwest to magnificent Cumberland Gap National Historical Park, it becomes obvious that air flowing across a wide region is going to be impacted by the HKL and the remnant massif of its highcountry.

My friend Geneva Varner, Superintendent of North Fork of Pound Dam in northern Wise County, has been a diligent worker for the U.S. Army Corps of Engineers and dedicated NWS Cooperative observer for many years.

Here is a monthly breakdown of her hand measured precipitation totals during the past 12-months.

North Fork of Pound Dam
Elevation: 1675 feet

2008
November: 2.40"
December: 5.45"

2009
January: 5.55"
February: 1.85"
March: 4.48"
April: 3.17"
May: 5.07"
June: 6.83"
July: 5.26"
August: 4.55"
September: 6.06"
October: 3.66"

2009 Total: 46.48"
12-Month Total: 54.33"

[ Only the amount which fell after 8 AM on October 31 is not included ].

Although above average, the monthly precipitation totals at North Fork of Pound Dam are strikingly less than those observed at Big Cherry Dam of High Knob, and amid its adjacent lifting zone, via significant moisture robbing leeward of the HKL, and its remnant massif, on southerly air flow trajectories.

My friends Wayne & Genevie Riner report monthly precip totals that reflect much the same at their official NWS Coop station ( Nora 4 SSE ) atop beautiful Long Ridge of Sandy Ridge in the highlands of southern Dickenson County.

Golden Maples and Yellow Poplars - October 2009
Photograph by Wayne Riner - © All Rights Reserved.

Long Ridge of Sandy Ridge - Nora 4 SSE
Elevation: 2650 feet

2008
November: 2.35"
December: 6.18"

2009
January: 5.35"
February: 2.33"
March: 4.12"
April: 3.31"
May: 5.75"
June: 8.51"
July: 3.62"
August: 3.97"
September: 4.12"
Oct 1-Nov 1: 3.27"

2009 Total: 44.35"
12-Month Total: 52.88"

Long Ridge sits on the Tennessee Valley Divide, like the adjacent Wise Plateau, and monthly precipitation totals there are impacted by wind induced rain gage undercatches.  However, since these are not accounted for in standard reporting, the totals above are comparable to those observed at Big Cherry Dam of High Knob, except that the Big Cherry monthly totals also have evaporative losses ( as previously noted ). 

Wayne & Genevie measure every day by hand on Long Ridge, so there should be very little evaporative loss for Nora 4 SSE.

Autumn On Long Ridge of Tennessee Valley Divide
Looking Toward Northeast End Of Pine Mountain
Photograph by Wayne Riner - © All Rights Reserved.

When standing upon the highlands of southern Dickenson County, looking across the Russell Fork Basin toward Pine Mountain and Breaks Interstate Park, as so beautifully illustrated by Wayne's gorgeous autumn photography, it is rather difficult to think about moisture robbing on downsloping winds!

However, indeed, it is true that Long Ridge is within the rain and snow shadow of the High Knob Massif and its extended landform on WSW to SW air flow trajectories, with significant moisture extraction downstream of the High Knob highcountry. 

Again, the numbers do not lie with 27.57" less hand-measured precipitation on Long Ridge than at Big Cherry Dam during the past 12-months on just the RAW gage readings ( both sites have wind induced rain gage undercatches ).

In reality, of course, when adding in the 3.00" of evaporation losses at Big Cherry Dam, the true rain gage departure would find Big Cherry having had 30.57" more during the past 12-months.

That is a VERY impressive difference, given Big Cherry Dam is just 470 vertical feet higher in elevation than Nora 4 SSE.

The real cause, or literal forcing for this difference, not being directly due to the elevation of Big Cherry Dam, but rather to the atypically WIDE expanse of the High Knob highcountry and the forced lifting of air from the floors of the river valleys to above the summit level of the 4223 foot massif.

[ There is more MEAN lift on all air flow trajectories into the large High Knob Massif verses Long Ridge. When combined with moisture extraction and downsloping leeward of the High Knob highcountry, on moisture rich SW winds ( especially ), this results in less total precipitation on Long Ridge ].

Tennessee Valley Divide-Pine Mountain Ring Russell Fork Basin
Photograph by Wayne Riner - © All Rights Reserved.

The highlands along the Tennessee Valley Divide, upon which Long Ridge rests, in combination with the HKL and its remnant highcountry massif, collectively work to increase total moisture extraction farther northeast into the lower elevations of northern Dickenson and Buchanan counties.

[ This moisture robbing impact actually extends much farther northeast into southern West Virginia on SW winds, and into portions of eastern Kentucky on S, SE, and E winds.  It also has both an interesting and very important impact upon the upper Clinch River Basin, as will be noted later ].

This loss of precipitation on moisture bearing southerly winds is reflected by rain gage measurements, such as those made within the Haysi, Birchleaf, Sandlick, and Grundy communities.

Here is a monthly breakdown for the official NWS cooperative station at the Mountain Mission School near Grundy, within the Levisa Fork Valley of Buchanan County.

Mountain Mission School - Grundy
Elevation: 1170 feet

2008
November: 2.49"
December: 5.01"

2009
January: 4.75"
February: 1.28"
March: 3.81"
April: 2.66"
May: 8.24"
June: 3.44"
July: 5.34"
August: 3.69"
September: 2.95"
Oct 1-Nov 1: 3.48"

2009 Total: 39.64"
12-Month Total: 47.14"

The Grundy 12-month total is nearly 6.00" less than measured atop Long Ridge, and 33.31" ( 36.31" when factoring in the evaporative loss ) less than measured at Big Cherry Dam.

The long-term implications of these moisture differences are truly vast, given that they are not only significant but are consistently significant over the longer term.

For example, in the entire 45-year precipitation record of Clintwood there has NEVER been a January to December period with 60.00" of total precipitation.  Since 1964 the greatest Jan-Dec totals on record were 58.78" in 2003, 58.68" in 1989, and 58.30" in 1975.  FAR below the current January-October total for Big Cherry Dam of High Knob!

[ Steve Mullins, Superintendent of the Clintwood Wastewater Treatment Plant, and his staff measured 59.18" on the northeast side of town during 2003 ].

The greatest 12-month precipitation total in Clintwood reached 61.08" during the November 1988 to October 1989 period.  FAR below current one year precipitation totals within the High Knob Massif area, and 20-30"+ less than MAX 12-month totals.

Here's the Current Monthly Breakdown.

Clintwood 1 W NWS
Elevation: 1560 feet

2008
November: 2.51"
December: 5.81"

2009
January: 5.33"
February: 2.45"
March: 4.49"
April: 3.62"
May: 5.28"
June: 8.06"
July: 6.32"
August: 4.14"
September: 5.41"
Oct 1-Nov 1: 3.67"

2009 Total: 48.77"
12-Month Total: 57.09"

The current 12-month total in Clintwood is 15.23" less than measured in the City of Norton, and 23.36" less than Big Cherry Dam of High Knob ( -26.36" when adding evaporative losses ).

For this western Appalachian Front Range location of Clintwood, the ONLY way that this consistency could be maintained over such a relatively long period ( 45-years ) is by the domination, within the MEAN, of significant downsloping and moisture extraction leeward of the High Knob Landform ( and Black Mtn ) on moisture rich SOUTHERLY air flow trajectories!


Regional Precipitation Point Samples

An inspection of 2009 and 12-month precipitation totals from other parts of the region reveals some rather significant variations via a few selected point samples.

2009 Total / 12-Month Total

Virginia
Richmond: 31.64" / 39.22"

Charolettesville: 32.56" / 37.79"

Roanoke: 39.09" / 43.26"

Bland: 39.70" / 45.57"

Wytheville: 41.52" / 46.63"

Richlands: 42.01" / 48.52"

Blacksburg: 42.16" / 47.54"

Lebanon: 44.40" / 52.08"

West Virginia
Martinsburg: 28.91" / 34.98"

Beckley: 38.06" / 45.22"

Bluefield: 39.27" / 44.77"

Elkins: 46.65" / 55.55"

Tennessee
Tri-Cities: 40.03" / 46.53"

Knoxville: 50.79" / 63.18"

Kentucky
Lexington: 49.04" / 57.60"

Jackson: 49.31" / 59.20"

London: 50.05" / 57.56"

A general east to west increase in both 2009 and 12-month precipitation totals is evident across the state of Virginia, with extreme variations of up to 4 FEET of total precipitation ( rain + melted snow ) between wetter parts of the High Knob Massif and drier portions of central-eastern Virginia.

Martinsburg, amid the shadow of the northern West Virginia highlands, reports among the lowest 2009 and 12-month tallies, with 34.98" during the past year being 45.47" less than measured at Big Cherry Dam of High Knob ( 48.47" less when adding in the 3.00" evaporative loss at Big Cherry ).

Locations west of the Appalachian Mountains in Kentucky, from the rugged foothills into the bluegrass, have measured more total precipitation during 2009 and the past 12-months than most places subjected to the more direct, stronger downsloping and moisture extraction leeward of the HKL ( since the best robbing of moisture for them occurs on SE air flow trajectories which are less common in the MEAN ).

Large precipitation variations during the past 12-months can be seen between the City of Norton ( 72.32" ) and locations within adjacent Russell & Tazewell counties, at Richlands ( 48.52" ) and Lebanon ( 52.08" ), as well as in the Tazewell-Bluefield ( 44.77" ) area at the head of the Clinch River. 

These large annual precipitation extremes have been well documented ( since 1990 ) by NWS rain gages as being common, and generate the rather anomalous pattern of DECREASING moisture upstream, northeast of the HKL, in the ecologically diverse Clinch River Basin.

[ In most river basins precipitation INCREASES upstream into their headwaters.  This anomalous pattern within the Clinch River Basin, of significant decreases in annual precipitation upstream of the High Knob Massif, has played important roles ( perhaps THE KEY role ) in establishing its vast diversity of life forms via the presence of significant climatic gradients upon which diversity naturally depends.

As stated by Frank Kilgore, this could be "the missing link" in understanding the epi-center of biodiversity which has developed across the truly wondrous Clinch-Powell River watersheds of the Upper Tennessee River Basin.

Panorama Across Clinch River Valley to HKL
Photograph by Richard Kretz - © All Rights Reserved.
  
In this beautiful panorama by photographer and naturalist Richard Kretz, the HKL appears only as a long, blue swell upon the horizon of the majestic Clinch River Valley.


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