Friday, May 6, 2011

WET & Stormy Days In The High Knob Landform


April 22, 2011
Clear Creek Basin of High Knob Massif
Painted Trillium ( Trillium undulatum )
Photograph by Roddy Addington - © All Rights Reserved.

Amid the weather chaos of Spring 2011 my friend & photographer Roddy Addington shows that Mother Nature is on schedule and hard at work, busily filling the mountain landscape with new life and great beauty!

April 22, 2011
Clear Creek of the Clinch River Basin
Awesome Beauty of Painted Trillium
Photograph by Roddy Addington - © All Rights Reserved.

Wetness ruled the High Knob Landform ( HKL ) and its remnant massif of highcountry during the 68 day period between February 21 & April 30, with my friend Gary Hampton measuring 22.68" of total precipitation at Big Cherry Dam ( a 2.33" per week rate for almost 10 weeks ). 


Big Cherry Dam of 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"
October: 4.36"
November: 3.88"
*December: 11.50"

2010
*January: 6.25"
*February: 4.25"
*March: 4.50"
April: 3.78"
May: 6.99"
June: 9.53"
July: 4.27"
August: 8.91"
September: 2.88"
October: 2.84"
November: 4.05"
*December: 7.35"

2011
January: 4.51"
February: 4.53"
March: 9.85"
April: 10.08"

2011 Total: 28.97" ( M )
( Does not include the 1.00"+ of rain during May 1-3 )

Nov 2010-April 2011 Total: 40.37" ( M )
Orographic Forcing Season
( 6.73" per month average )

12-Month Total: 75.79" ( M )

24-Month Total: 151.41" ( M )

30-Month Total: 188.76" ( M )

30-Month Mean Monthly Precip: 6.29"

Mean Per 12-Month Periods: 75.50" ( M )

( * ) - Indicates that total was estimated or partly estimated due to severe winter conditions and deep falls of snow ( i.e., more snow fell than the rain gage could physically hold ).

( M ) - Denotes that total precipitation was greater than rain gage total due to evaporation between hand-measurements and physical gage loss in deep falls of snow ( the mean evaporative loss is estimated to have been 3.00" to 3.50" per year as partly based upon observed losses at Clintwood 1 W ).

[ All measurements courtesy of Superintendent Gary Hampton and Staff at the Big Stone Gap Water Plant in South Fork Gorge ].

The combined March-April period produced 19.93" of precip at Big Cherry Dam during a total of 9 hand-measurements taken on the NWS gage ( about 1 per week ), such that the actual fall was more than 20.00" given evaporation between readings.

April 22, 2011
Clear Creek Basin of High Knob Massif
Amazing Array Of Mushrooms Part Of New Life
Photograph by Roddy Addington - © All Rights Reserved.

Another extraordinary precipitation gradient has set up across the state of Virginia, with wetness fading eastward from the High Knob Massif to yield actual drought conditions in southeastern portions of the Old Dominion.


Although this short-term drought map does not show the true magnitude of High Knob Massif wetness, it does illustrate the general west to east gradient across Virginia.


Actual numbers reveal the true story of the past 6 months, with 40.37" of precipitation at Big Cherry Dam of the High Knob Massif verses only 11.78" on Wallops Island, along the Atlantic Coast, during the November 2010 to April 2011 period.

[ Remembering that due to moisture losses in deep falls of winter snow, which did not occur on Wallops Island, and losses in between hand-measurements, that actual amounts falling at the Big Cherry Dam point were greater than measured in its NWS rain gage ( i.e., there was easily a 30.00" precipitation difference between Wallops Island and wetter parts of the High Knob Massif during this 6 month period ) ].

A look at selected points across Virginia reveals the true nature of this west-east precipitation gradient.


Precipitation Totals For April, March-April,
And The Year of 2011 From Across
The State Of Virginia 
( January 1-April 30 )

West Point 2 NW
April Rain: 1.95"
March-April: 4.75"
2011 Precipitation: 5.86"

Eastville
April Rain: 1.01"
March-April: 4.26"
2011 Precipitation: 7.78"

Newport News 3.3 E
April Rain: 1.76"
March-April: 4.68"
2011 Precipitation: 8.59"
( 1 day missing January )

Wallops Island
April Rain: 1.60"
March-April: 4.34"
2011 Precipitation: 9.02"

Williamsburg 2 N
April Rain: 2.29"
March-April: 5.54"
2011 Precipitation: 9.24"
( 1 day missing January )

Norfolk
April Rain: 1.21"
March-April: 4.17"
2011 Precipitation: 10.05"

Painter 2 W
April Rain: 1.95"
March-April: 5.69"
2011 Precipitation: 10.43"
( 2 days missing April )

Danville
April Rain: 3.19"
March-April: 7.41"
2011 Precipitation: 10.63"

Lynchburg
April Rain: 5.36"
March-April: 8.05"
2011 Precipitation: 11.47"

Richmond
April Rain: 2.63"
March-April: 6.91"
2011 Precipitation: 11.48"

Roanoke
April Rain: 5.33"
March-April: 9.58"
2011 Precipitation: 12.58"

Pulaski 2 E
April Rain: 4.88"
March-April: 11.23"
2011 Precipitation: 13.04"

Edinburg
April Rain: 7.30"
March-April: 10.95"
2011 Precipitation: 13.11"
( 1 day missing February )

Covington Filter Plant
April Rain: 6.89"
March-April: 11.45"
2011 Precipitation: 13.14"

Lexington
April Rain: 5.44"
March-April: 10.93"
2011 Precipitation: 13.28"

Staunton Water Treatment Plant
April Rain: 5.73"
March-April: 10.68"
2011 Precipitation: 13.35"

Blacksburg
April Rain: 5.19"
March-April: 9.57"
2011 Precipitation: 13.37"

Kerrs Creek 6 WNW
April Rain: 6.69"
March-April: 12.09"
2011 Precipitation: 13.77"

Charlottesville
April Rain: 5.24"
March-April: 11.48"
2011 Precipitation: 14.06"

Wytheville 1 S
April Rain: 4.95"
March-April: 11.36"
2011 Precipitation: 14.14"

Galax Water Treatment Plant
April Rain: 5.34"
March-April: 12.61"
2011 Precipitation: 14.42"

Gathright Dam
April Rain: 7.82"
March-April: 13.07"
2011 Precipitation: 15.14"

Bluefield ( WV )
April Rain: 4.97"
March-April: 10.13"
2011 Precipitation: 15.62"

Bland
April Rain: 4.61"
March-April: 12.00"
2011 Precipitation: 15.65"
( 3 days missing January )

Richlands
April Rain: 6.14"
March-April: 12.54"
2011 Precipitation: 16.02"

Trout Dale 3 SSE
April Rain: 4.97"
March-April: 12.59"
2011 Precipitation: 16.15"

Holcomb Rock
April Rain: 6.62"
March-April: 13.13"
2011 Precipitation: 16.24"

Grundy
April Rain: 6.50"
March-April: 12.91"
2011 Precipitation: 16.31"

Burkes Garden
April Rain: 5.04"
March-April: 12.99"
2011 Precipitation: 17.50"

Copper Hill
April Rain: 8.60"
March-April: 14.94"
2011 Precipitation: 17.65"

Saltville 1 N
April Rain: 5.80"
March-April: 13.24"
2011 Precipitation: 17.70"

Hot Springs
April Rain: 8.64"
March-April: 15.04"
2011 Precipitation: 17.74"
( 1 day missing January )

Clintwood 1 W
April Rain: 6.73"
March-April: 13.08"
2011 Precipitation: 17.78"

Millgap 2 NNW
April Rain: 9.23"
March-April: 15.69"
2011 Precipitation: 18.07"

Nora 4 SSE
April Rain: 6.92"
March-April: 14.31"
2011 Precipitation: 18.37"

Lebanon
April Rain: 7.58"
March-April: 15.15"
2011 Precipitation: 18.44"

Marion 4.4 WSW
April Rain: 5.89"
March-April: 14.08"
2011 Precipitation: 18.53"
( 2 days missing March )

Meadows Of Dan 5 SW
April Rain: 7.54"
March-April: 16.15"
2011 Precipitation: 18.99"

Woolwine
April Rain: 6.35"
March-April: 16.64"
2011 Precipitation: 19.19"

Appalachia Lake Water Plant
April Rain: 7.75"
March-April: 15.38"
2011 Precipitation: 20.68"

City of Norton Water Plant
April Rain: 8.66"
March-April: 17.04"
2011 Precipitation: 22.99"

Robinson Knob of High Knob Massif
April Rain: 8.58"
March-April: 18.45"
2011 Precipitation: 24.98" ( M )

( South Fork Gorge )
Big Stone Gap Water Plant
April Rain: 9.31"
March-April: 18.75"
2011 Precipitation: 25.57"

Big Cherry Dam of High Knob Massif
April Rain: 10.08"
March-April: 19.93"
2011 Precipitation: 28.97" ( M )

( M ) - Denotes missing data during the year due to evaporation between hand-measurements and snowfall.


Climate Statistics
For April 2011

April 22, 2011
Clear Creek Basin of High Knob Massif
Weather For The Ducks - Rippling Water
Photograph by Roddy Addington - © All Rights Reserved.

Clintwood 1 W - Elevation 1560 feet
Average Daily MAX: 69.8 degrees
Average Daily MIN: 40.8 degrees
MEAN: 55.3 degrees
Highest Temperature: 85 degrees
Lowest Temperature: 27 degrees
Total Precipitation: 6.73"
Total Snowfall: Trace
2011 Precipitation: 17.78"

City of Norton - Elevation 2141 feet
Average Daily MAX: 65.3 degrees
Average Daily MIN: 40.1 degrees
MEAN: 52.7 degrees
Highest Temperature: 80 degrees
Lowest Temperature: 25 degrees
Total Precipitation: 8.66"
Total Snowfall: 0.5"
2011 Precipitation: 22.99"

Nora 4 SSE - Elevation 2650 feet
Average Daily MAX: 64.1 degrees
Average Daily MIN: 44.7 degrees
MEAN: 54.4 degrees
Highest Temperature: 77 degrees
Lowest Temperature: 26 degrees
Total Precipitation: 6.92"
Total Snowfall: Trace
2011 Precipitation: 18.37"

In the High Knob highcountry, April temp means varied from 50s to lower 60s by day to the 30s to lower 40s at night.

Precipitation was abundant, with 8.50" to 10.00"+ being common to include a general 1" to 4" of snow above 3000 feet.


( Updated: May 6, 2011 )
May 2011 Begins Wet & Chilly

City of Norton - April 26, 2011
Towering Cumulus Build Into Local Thunderstorms
Photograph by Roddy Addington - © All Rights Reserved.

Widespread freezing conditions followed soaking rain to open up the new month of May, with temps below freezing at highest elevations during both mornings of May 4-5.

Mins in the 20s to around 30 degrees were widespread across mid to upper elevations into morning hours of May 5, to include the City of Norton where heavy frost formation occurred.

[ Temps also dropped to around freezing in colder mountain valleys of mid-upper elevations into AM hours of May 6-7 ].

May 1-6 ( AM ) Statistics
City of Norton - Elevation 2141 feet
Average Daily MAX: 66.7 degrees
Average Daily MIN: 38.2 degrees
MEAN: 52.4 degrees
Highest Temperature: 75 degrees
Lowest Temperature: 29 degrees
Rainfall: 1.34"
2011 Precipitation: 24.33"
Nov 1, 2010 to May 4, 2011: 34.00"
( 41.50"+ at Big Cherry Dam since Nov 1 )

More than 30.00" at Big Cherry Dam has now pushed the 10 week precip tally to 2+ feet in wetter parts of the High Knob Massif, stretching the west-east gradient across Virginia to more than 30.00" since the beginning of November 2010 and the start of the orographic forcing season ( i.e., totals of 40" to 45" in wetter parts of the High Knob highcountry verses less than 11" in portions of eastern Virginia since Nov 2010 ).

A specific example of this extreme difference in precipitation across the Old Dominion during the past 6 months is well illustrated by the Eastville NWS Cooperative station in Northampton County, at 10 feet above mean sea level, where 10.71" were measured from November 1, 2010 to May 5, 2011.

[ The National Weather Service Cooperative in Eastville has been in service for 102 years since November 1, 1909 ].


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