Wednesday, September 1, 2010

Summer 2010: Wet & Humid In The HKL


Jefferson National Forest
High Knob Lake - Water Elevation 3490 feet
Cool Morning In The Highcountry - Aug 8, 2010
Photograph by Roddy Addington - © All Rights Reserved.

The High Knob Landform

A thin layer of steam fog hovered over the surface of High Knob Lake during one of the few truly cool mornings of August 2010, with 50 to 55 degree minimums within highcountry basins.

[ Some chilly mornings would be felt during the final days of the month, as will be detailed later in this section ].

High Knob Lake Basin - August 2010
Entoloma Mushroom Species In Morning Light
Photograph by Roddy Addington - © All Rights Reserved.

August 2010 is capping off a summer of wetness in the High Knob Landform ( HKL ), with copious rainfall and high humidity levels working in combo to generate an array of atypically warm nights.

High Knob Lake Basin
Fern Growing Inside Tree Covered By Bryophytes
Photograph by Roddy Addington - © All Rights Reserved.

For the vast number of resident fungi, fern, and bryophyte species living within the HKL late spring and summer 2010 has offered nearly ideal growing conditions ( with up to 30+ inches of rain since the beginning of May ).

High Knob Lake Basin
Gorgeous Coral Mushroom - August 2010
Photograph by Roddy Addington - © All Rights Reserved.

Climate Statistics for August 1-20
( A complete recap of August & Summer Stats
will be highlighted after the month ends ).

City of Norton - Elevation 2141 feet
Average Daily MAX: 83.9 degrees
Average Daily MIN: 62.6 degrees
MEAN: 73.2 degrees
Highest Temperature: 89 degrees
Lowest Temperature: 55 degrees
August 1-20 Rainfall: 7.01"
Growing Season Rainfall ( since May 1 ): 23.72"

August 2010 has been the warmest month of the summer, despite its lack of "official" 90 degree days within mid-upper elevations of the High Knob Massif area ( above 2000 feet ).

[ Only 2 days during 2010 ( as of August 20 ) reached 90 degrees in Norton, with no days officially breaking 90 above 2800 feet in elevation ]. 

It has also turned into the wettest month on average with a general 7.00" to 12.00"+ of rainfall from the City of Norton into the Clinch River Valley of Scott County ( growing season rainfall at Norton Water Plant, since May 1, actually coming in among the lower tallies due to a near record dry July in the City of Norton ).

Powell Valley Overlook of High Knob Massif
An August Jungle In The Southern Appalachians
Photograph by Roddy Addington - © All Rights Reserved.

Wispy fog rising upward from jungle-like humidity and wetness has been very common, especially during the convectively active period of August 10-19.

Prelude to Significant Flash Flooding
Documentation of
August 10-19 Period
( Orographics & Feedbacks )

Grindstone Ridge Dome of High Knob Massif
Orographic Cloud - August 11, 2010
Photograph by Roddy Addington - © All Rights Reserved.

Orographics have played more of a role in the rainfall pattern during August, as they did during May & June, after more of a feedback dominated July across the High Knob Landform.

For more information about summer feedbacks and orographic influences on convective patterns, reference the following section of my website:


High Knob Massif - August 11, 2010
Stationary Orographic Clouds at Multiple Levels
 Photograph by Roddy Addington - © All Rights Reserved.

Note that orographic comes from the Greek "oros," meaning mountain, and "graphein" meaning to describe, such that an orographic effect is literally a description of the effects of mountains on weather and climate.

Although orographics played a role in numerous torrential rainfall events during August, the wet feedback established over the Scott County side of the massif in July continued to clearly exert an influence by aiding enhancement of rain amounts within the same, general area on consecutive days ( thus, the build up to the significant Scott County flash flooding on August 19 was not just by chance ).

Showers and downpours in thunderstorms got going during August 10, with 0.50" to 1.00"+ of Doppler estimated rain in the area of The Glades of the High Knob Massif.

JKL Doppler Rainfall Estimate at 10:59 PM - Aug 10
Image Courtesy of Plymouth State University

The above was verified by mushroom and berry hunter Johnny Stanley who got caught under a deluge in the Edith Gap section of the massif near The Glades ( in northern Scott County ).

[ Johnny reported that rain fell so fast that it overflowed the ditch lines, with torrents running across several roadways ]. 

JKL Doppler Rainfall Estimate at 11:00 PM - Aug 11
Image Courtesy of Plymouth State University

Large thunderstorms developed above the High Knob Massif during August 11, with a notable southwestward propagation across the very long backslope of the massif in northern Scott County ( from The Glades to the Duffield Valley & Stickleyville Basin of northeastern Lee County ).

More Orographic Clouds Visible On Wise County Side
Large Thunderstorms Build Over Massif - Aug 11
Photograph by Roddy Addington - © All Rights Reserved.

My friend & photographer Roddy Addington documented these thunderstorms on August 11, which dropped Doppler estimated 1.00" to 3.00" rainfall amounts from South Fork Gorge and the lower Big Cherry Basin of Wise County across much of the Scott County side of the massif.

August 11, 2010
Powell Valley Overlook of High Knob Massif
Trailing Inflow - Thunderstorms Move SE Off Massif
Photograph by Roddy Addington - © All Rights Reserved.

Formation of these thunderstorms marked an important turning point for the drought baked Tri-Cities of northeast Tennessee, with movement off the High Knob Landform and its remnant massif of highcountry into the lower terrain of the Great Valley where 1.20" of rain officially fell at TRI ( marking the first 1.00"+ rain event in 3 LONG, dry months! ).

[ By no coincidence, the TRI would go on to receive several more needed downpours during the next week as a DENT was finally put into its rain hindering dry feedback shield courtesy of storms erupting above the wetness of the High Knob Landform ( HKL ) ].

August 11, 2010
Sky Turns Colorful In Wake of Storms
 Photograph by Roddy Addington - © All Rights Reserved.

The focus of storm formation during August 12 again zeroed in on the South Fork Gorge to Cove Creek Gorge section of the massif, with Maple Gap, Thunderstruck Knob, and the upper Stock Creek Basin all getting in on Doppler estimated 1.00" to 1.50"+ rainfall amounts.

JKL Doppler Rainfall Estimate at 11:00 PM - Aug 12
Image Courtesy of Plymouth State University

[ Another corridor of concentrated heavy rains developed from southeastern slopes of the High Knob Massif across a portion of the Clinch River Valley and Copper Ridge of Scott County ].

The next huge thunderstorms went up over the High Knob Massif into early afternoon hours of August 13, with great cumulonimbus towers soaring 8 to 10 vertical miles into the heavens!

2-Day Doppler Estimate
JKL Doppler Rainfall Estimate at 11:01 PM - Aug 13
Image Courtesy of Plymouth State University

Booming thunder from these giants could be heard all the way north to Clintwood, with huge tops being clearly visible toward the south and southwest.

Doppler Base Reflectivity at 2:58 PM - August 13, 2010
Image Courtesy of Plymouth State University

Day turned to night as 1.00" to 1.50"+ rains fell from parts of Wise southeast into the highcountry around the High Chaparral and Robinson Knob communities of High Knob.

The most intense rains fell with repetitive backbuilding along the northwestern flank of the HKL, with Doppler estimated 2.00" to 3.00" rain amounts between High Butte and the "Big Stone Gap" of Stone Mountain ( southwestern Wise County ).

Otherwise, the big storms of this afternoon laid down additional heavy rains upon the same places already hit hard by August 11-12 storm activity across northern Scott County.

3-Day Rainfall Estimate
JKL Doppler Rainfall Estimate at 2:59 AM - Aug 15
Image Courtesy of Plymouth State University

With a few additional August 14 storms the area inside of the white ellipse illustrated previously was well covered by the early hours of August 15 ( having only a few embedded dry pockets ).

August 2010
Mushroom In High Knob Lake Basin
Photograph by Roddy Addington - © All Rights Reserved.

A welcomed break was observed across most of the area during August 15, with only a few isolated exceptions from Guest River Gorge into the Clinch River Valley and Tennessee Valley Divide.

JKL Doppler Rainfall Estimate at 10:58 PM - Aug 15
Image Courtesy of Plymouth State University


Trouble Ahead Revealed
In Series of Sunrise Photographs

August 16, 2010
High Knob Massif from Powell Valley
Orographic Wave Clouds In Morning Light
Photograph by Roddy Addington - © All Rights Reserved.

A simply gorgeous set of sunrise photographs captured by Roddy Addington from the rolling floor of majestic Powell Valley, in Wise County, Va., might initially appear innocent enough.

Second View in Time Series
Wave Clouds In August Sunrise - August 16, 2010
Photograph by Roddy Addington - © All Rights Reserved.

Wave clouds above the High Knob Massif are a common sight during much of the year, but are expected from a climatological perspective to be observed least during the month of August.

[ August typically possesses the lightest wind fields of the year, such that orographic forcing is generally weak and not conducive to driving wave cloud formation off the terrain ].

Third & Final View in Morning Series
Stacked Lenticular Forms - August 16, 2010
Photograph by Roddy Addington - © All Rights Reserved.

This morning sunrise series revealed that not only are these orographic wave clouds, but that they are a very special form known as stationary lenticular clouds ( although not as spectacular as many observed during the orographic forcing season from Nov-April ).

[ Lenticular wave clouds are not expected in August, with these forming in 15 knots of NW flow near and just above the summit level of the High Knob Massif ].

Any time gravity waves are present they indicate that both vertical and horizontal energy transfer is likely, which during the summer season can be especially important given large amounts of CAPE ( Convective Available Potential Energy ) latent within high dewpoint air ( also suggested by abundant fog in above photographs along Powell Valley floor and walls ).

Gravity waves tend to form concentrations of cloud water vapor in their ascent regions that are richer than those generated only by upsloping alone, such that they can aid rainfall enhancement ( under and adjacent to their gravity wave source area ).

NAM Model Initialization at 8 AM on August 16, 2010
Image Courtesy of Unisys Weather Processor

An inspection of morning weather charts revealed the setting, with NW wind vectors visible on the 850 mb panel in upper left representing the air flow pushing against the High Knob Massif.

The massif was in turn forcing gravity wave formation, with the lenticular clouds visible in the above photographs standing at the crest of the wave ( like at the top of an ocean wave ).

The upper right panel above supports this rather anomalous setting by showing an actual phasing, or coupling, of Pacific & Polar jet streams that is more analogous to an autumn or winter setting, with atypically strong westerly winds aloft flowing across the Ohio Valley.

NAM Model Initialization at 8 PM on August 16, 2010
Image Courtesy of Unisys Weather Processor

A strong cold front to the northwest, driven by anomalously deep low pressure over Hudson Bay in Canada, was becoming aligned along a strong moisture and instability gradient easing southeast across Kentucky during the day ( much more stable, drier air north to northwest of the mountains can be noted on the lower right chart above ).

Something had to give!

Doppler Base Reflectivity at 6:49 PM on August 16
Image Courtesy of Plymouth State University

And, of course, it was MORE thunderstorms!

2-Day Doppler Totals
JKL Doppler Rainfall Estimate at 9:56 PM on Aug 16
Image Courtesy of Plymouth State University

The heaviest rains became concentrated along the Clinch River Valley, with widespread 0.50" to 2.50"+ amounts again falling upon the High Knob Massif of northern Scott County into Big Cherry Basin of Wise County.

These storms were only the beginning of an all out assault by Mother Nature, as the above parameters would combine with the northeastward surge of remnant moisture from Tropical Depression 5 to force 17.5 vertical feet of rise on the Clinch River, downstream of the High Knob Massif, by late on August 19 ( details and flood pictures to follow below ).

JKL Doppler Rainfall Estimate at 11:00 PM on Aug 17
 Image Courtesy of Plymouth State University

The first wave of tropical moisture worked across the Tennessee Valley during August 17 with destructive aim taken once again on already water logged Scott County, Va., as torrential rains set up along and southeast of the High Knob Landform.

[ The heaviest 2.00" to 3.00"+ Doppler estimates falling from the Rye Cove Basin east and southeast across the Clinch River into portions of Copper Ridge and Clinch Mountain ].

The terrible and tragic death of a Weber City teenager, who got swept into a storm drain by flood waters on this evening, added to a horrible list of flood related deaths in the region this year.

NAM Model Initialization at 8 AM on August 18, 2010
Image Courtesy of Unisys Weather Processor

Daylight hours of August 18 were dominated by low clouds, fog, and a shield of light to moderate rain from the High Knob Landform west and north.

[ Temperatures remained relatively cool, with narrow spreads between day and night.  MAXS in the 60s to lower 70s and MINS in the 60s indicated that it also remained plenty humid enough for more heavy rain! ].

NAM Model Initialization at 8 PM on August 18, 2010
Image Courtesy of Unisys Weather Processor

[ Note the surface low over Arkansas and the 850 MB low over western Tennessee, on the above charts, representative of the remnants of Tropical Depression 5 ].

Heaviest local rain totals during August 18 were observed along northern slopes of the High Knob Massif, with 1.00" to 1.50" from Appalachia and Norton to Tacoma and Coeburn.

It was a miracle, pure and simple, that flooding rains which fell through morning hours of August 18 across southern Kentucky and the northern Cumberland Plateau of Tennessee did not reach into the mountains of southwestern Virginia.

Graphic Courtesy of Jackson, Ky., NWSFO

However, another batch of tropical moisture was surging north into middle Tennessee as displayed within the BLUE outline below on Water Vapor imagery.

NASA Water Vapor Image at 5:15 PM on August 18

While seeming to weaken, with Doppler radar looking rather anemic by late evening of August 18, a real fear remained alive in the minds of those who understood that remnant tropical systems often go through distinct diurnal cycles which force inflow and convergence to begin during the night!


Flash Flood - River Flood Event
( August 19, 2010 )

Doppler Base Reflectivity at 5:30 AM - August 19
Image Courtesy of Plymouth State University

That was certainly the case as heavy overnight rains and downpours developed quickly into the predawn hours of August 19 with a rapid spread northeast along the High Knob Landform and Upper Tennessee River Basin.

NAM Model Initialization at 8 AM on August 19, 2010
Image Courtesy of Unisys Weather Processor

Morning weather charts revealed a weak low pressure that were the remnants of former TD 5 .  This supported enhanced convergence of moist, tropical air along its path and into the HKL and its massif of highcountry.

3-Day Rainfall Estimate
Doppler Radar Rainfall Estimate at 5:58 PM on August 19
Image Courtesy of Unisys Weather Processor

Although the above graphic looks impressive, Doppler radar actually under-estimated rainfall totals that were measured by rain gauges during August 18-19.  This being due to the fine dropped, fast falling tropical rains and to the orographic enhancement of rainfall across the High Knob Massif along the borders of Wise, Scott, and Lee counties ( due to the torrential nature of this rainfall, tipping-bucket gauges also recorded less than hand-measured gauges ).


Flood Photographs
( A Few Examples of Many )

The following photographs were submitted by viewers to meteorologist Dave Dierks & the News 5 weather team of WCYB-TV in the Tri-Cities of northeast Tennessee.

August 19, 2010
Flash Flooding - Fort Blackmore Area of Scott County
Photograph by Megan Darnell

Significant flash flooding developed all along the rugged Wise, Scott, and Lee county borders as very steep creeks draining the High Knob Massif funneled water into the Clinch-Powell rivers.

Some of the worst conditions developed across Scott County, Va., from Dungannon southwest to Fairview and The Sinks.

Flash Flooding In Dungannon Area - August 19, 2010
Photograph by Roger Hall

At least half a dozen families had to evacuate homes along Big Stony Creek in northern Scott County, marking the third time that some had to flee their residences during this very wet mid-July to mid-August period of 2010 ( a dangerous situation, with the flood plain of Big Stony Creek being one of the most flashy and potentially deadly in the entire region ).

August 19, 2010
Flooding in Fort Blackmore Area of Scott County
Photograph by Meagan Peak

Flash flooding became widespread along North Fork of the Clinch River which flows by Jasper and through The Divide into the Duffield Valley, The Sinks, Fairview, and Jennings Store from its head near the Wise-Lee border in the High Knob Massif.

August 19, 2010
Flash Flooding in Duffield - North Fork of Clinch River
Photograph by Dorothy Ricord

A river gage in Speers Ferry recorded an impressive 17.46 feet of vertical rise on the Clinch River, which remained above flood stage for just over 12-hours ( all the water seen in the above photograph, and the one below, dumping into the mainstem Clinch River downstream of Speers Ferry near Kyles Ford, Tn., and not included in the Speers Ferry rise ).

August 19, 2010
Flooding in the Fairview Community of Scott County
Photograph by Allen Vanstant

Flash flooding also developed within the Powell River watershed of Wise County, Va., as water gushed out of lofty Big Cherry Basin and off the steep northwestern slopes between Big Stone Gap and Norton ( look for a Big Cherry Dam precip update later ).

August 19, 2010
Flooding In Cracker Neck of Powell Valley
 Photograph by Mike Brady

Way too many homes had water surround them during this event, to make the meek showers and brief downpours of the August 21-22 weekend a welcomed sight as the heaviest passed just south of Scott County, Virginia.  Finally, a miss!

August 19, 2010
Mobile Homes In Dungannon Area of Scott County
Photograph by Shirley Forman

More downpours of rain developed across the High Knob Massif during August 26, with a notable concentration again across northern Scott County into the Clinch Valley of Russell County ( with 0.50" to 1.00" rainfall amounts ).

Doppler Radar Rainfall Estimate at 4:43 PM on August 26
Image Courtesy of Plymouth State University

This was part of a period that finally featured cooler nights, with low-mid 50s dominating higher mountain valleys during the August 23-31 period.

[ August 31 featuring the coolest morning of the month, with middle 40s to lower 50s being common in fog free valleys of mid-upper elevations ].


Climate Statistics For
August 2010

High Knob Massif - August 2010
Monarch Butterfly's ( Danaus plexippus )
On Beautiful Milkweed ( Asclepias spp. )
Photograph by Roddy Addington - © All Rights Reserved.

August 2010 ended warmer & wetter than average despite somewhat cooler air during the final ten days of the month across the High Knob Landform ( drier than normal N-NE of the HKL ).

Clintwood 1 W - Elevation 1560 feet
Average Daily MAX: 82.9 degrees
Average Daily MIN: 63.3 degrees
MEAN: 73.1 degrees
Highest Temperature: 90 degrees
Lowest Temperature: 57 degrees
August Rainfall: 3.73"
Summer Rainfall: 13.06"
2010 Precipitation: 31.97"
( -1.21" below 1971-2000 mean )

Breaks Interstate Park - Elevation 1893 feet
Average Daily MAX: 78.9 degrees
Average Daily MIN: 63.6 degrees
MEAN: 71.2 degrees
Highest Temperature: 86 degrees
Lowest Temperature: 57 degrees
August Rainfall: 1.65"
Summer Rainfall: 13.33"
2010 Precipitation: 32.24"
( 1 day missing in May )

City of Norton - Elevation 2141 feet
Average Daily MAX: 82.6 degrees
Average Daily MIN: 60.2 degrees
MEAN: 71.4 degrees
Highest Temperature: 89 degrees
Lowest Temperature: 53 degrees
August Rainfall: 7.65"
Summer Rainfall: 15.76"
2010 Precipitation: 39.13"
( -1.57" below 1983-2004 mean )

Long Ridge of Sandy Ridge
Nora 4 SSE - Elevation 2650 feet
Average Daily MAX: 80.7 degrees
Average Daily MIN: 65.3 degrees
MEAN: 73.0 degrees
Highest Temperature: 88 degrees
Lowest Temperature: 59 degrees
August Rainfall: 5.95"
Summer Rainfall: 14.36"
2010 Precipitation: 34.42"

In the High Knob highcountry August temp means varied from 70s by day above 2700 feet to mid-upper 50s by night in the cooler mountain basins ( August MINS reaching middle 40s to lower 50s ).

August rainfall totals were excessive across the High Knob Massif, varying from 6.66" on its rugged Little Stone Mountain arm, at Appalachia Lake Water Plant ( 6.7 air miles WSW of Norton WP ), to as much as 15.00" in the multi-gorge Big Stony Basin of northern Scott County.

( Updated August 4, 2012 )
Generalized Map of August 2010 Rainfall Totals

Climatology reveals that when there is a concentration of excessive precipitation across the High Knob Massif there tends to be a compensating area of enhanced subsidence and sinking of air, with much less precipitation, across the Russell Fork & Levisa Fork basins of the Big Sandy River given trajectories of air flow possessing southern components.

August 31, 2010
Morning Inversion In The High Knob Landform
  Photograph by Roddy Addington - © All Rights Reserved.

Looking southwest along the Powell River Valley, nestled between Wallen Ridge and the northwestern arm of the High Knob Landform, a layer of fog illustrates a strong morning temperature inversion to close out August 2010.

Sunrise temperatures varied from middle 40s to lower 50s in cooler basins of the High Knob highcountry to mid 60s in places well exposed to light winds.


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

2009
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"

Summer 2010 Total: 22.71" ( M )

( May-August )
Growing Season 2010: 29.70" ( M )

2010 Precipitation Total: 48.48" ( M )

12-Month Total: 77.31" ( M )

21-Month Total: 138.31" ( M )
( Mean of 6.59" per month )

24-Month Total: 148.06" ( M )
**( Mean of 6.17" per month )

( * ) - Denotes data loss during the harsh 2009-10 winter.

( M ) - Denotes that the actual total fall was greater than rain gauge amounts due to a combination of evaporation between the hand-measurements and losses amid wind & sub-freezing conditions.

( ** ) - With up to 6.00"+ of loss figured during the past 24 months ( September 2008 - August 2010 ) due to evaporation between the hand-measurements, a much more accurate mean monthly precipitation value would be approximately 6.42" per month.

[ Evaporation from the rain gauge varying from only 0.01" per week up to around 0.10" per week, with an estimated mean of 0.05" to 0.06" per week.  This is only from physical gauge loss and does not account for any losses due to wind induced undercatch in rain and frozen precipitation forms.

It also does not account for occasional significant losses in deep falls of snow, and does not account for any of the very important secondary additions to the water budget of Big Cherry Basin from fog drip off trees and rime deposition on trees. ].

Note:  All hand-measurements at Big Cherry Dam are courtesy of Gary Hampton, Superintendent of the Big Stone Gap Water Plant, and his staff.   

August 31, 2010
Morning Inversion Inside High Knob Massif
Photograph by Roddy Addington - © All Rights Reserved.

At about this time last year there had been an estimated 3.00" of evaporative loss at Big Cherry Dam, due to hand-measurements which average one per every 5 to 7 days ( based upon observed losses at my Clintwood NWS station for evaporation ).

During 2010 the loss from evaporation is figured to be about the same, despite warmer mean temps, since higher average humidity levels have tended to offset increased evaporation from higher average temperatures ( at least within the wetter, cloudier High Knob Massif area ).

Regardless of the exact value, it is certain that more than 30.00" of rain has accumulated across Big Cherry Basin since May 1 and the start of the growing season ( more than 50.00" of total precip in 2010, and 80.00"+ during the past 12-months, with addition of only the approximate evaporative losses from the rain gauge ).

August 2010
Mushroom Weather - High Knob Massif
Photograph by Roddy Addington - © All Rights Reserved.

Growing Season Rainfall
*Big Cherry Basin MAX Totals
( May 1 to August 31 of 2010 )

May: 10.00"

June: 9.75"

July: 6.25"

August: 9.00"

Rainfall Total: 35.00"

*Doppler radar estimated 8.00" to 10.00" of rain across Big Cherry Basin during August, with the mean value being used.  Much more rain is known to have fallen across the middle-upper basin during May, with significantly more also in July, than at the Big Cherry Dam measuring point.

Big Cherry Lake gained 55.9 million gallons of water during the August 10-20 period, with a 37.3 million gain during August 16-20 when 5.74" of rain were measured at the Dam ( more than 6.00" fell along Little Mountain during that period ).

The Lake overflowed its spillway during the final 13 days of August ( such that the total amount gained and spilled out of the Big Cherry Basin was much more than 55.9 million gallons ).

High Knob Lake Basin - August 2010
Eastern Tiger Swallowtail ( Papilio glaucus )
Silver-spotted Skipper ( Epargyreus clarus )
and Milkweed Bug on ( Asclepias spp. )
Photograph by Roddy Addington - © All Rights Reserved.


Regional Climate Statistics
For August 2010

Jackson, Ky., NWSFO - Elevation 1365 feet
Average Daily MAX: 87.0 degrees
Average Daily MIN: 67.7 degrees
MEAN: 77.4 degrees
Highest Temperature: 97 degrees
Lowest Temperature: 62 degrees
August Rainfall: 3.51"
Summer Rainfall: 12.45"
2010 Precipitation: 32.79"

London, Kentucky - Elevation 1211 feet
Average Daily MAX: 87.5 degrees
Average Daily MIN: 67.3 degrees
MEAN: 77.4 degrees
Highest Temperature: 95 degrees
Lowest Temperature: 59 degrees
August Rainfall: 6.03"
Summer Rainfall: 14.48"
2010 Precipitation: 32.74"

Buckhorn Lake State Park, Ky., - Elevation 780 feet
Average Daily MAX: 88.8 degrees
Average Daily MIN: 66.8 degrees
MEAN: 77.8 degrees
Highest Temperature: 98 degrees
Lowest Temperature: 57 degrees
August Rainfall: 7.92"
Summer Rainfall: 16.10"
2010 Precipitation: 33.33"

Tri-Cities, Tennessee - Elevation 1525 feet
Average Daily MAX: 89.6 degrees
Average Daily MIN: 66.5 degrees
MEAN: 78.0 degrees
Highest Temperature: 96 degrees ( 3 days )
Lowest Temperature: 58 degrees
August Rainfall: 6.26"
Summer Rainfall: 10.80"
2010 Precipitation: 23.50"

Knoxville, Tennessee - Elevation 981 feet
Average Daily MAX: 91.4 degrees
Average Daily MIN: 71.4 degrees
MEAN: 81.4 degrees
Highest Temperature: 98 degrees
Lowest Temperature: 64 degrees
August Rainfall: 2.80"
Summer Rainfall: 9.94"
2010 Precipitation: 28.54"

Chattanooga, Tennessee - Elevation 683 feet
Average Daily MAX: 94.4 degrees
Average Daily MIN: 73.7 degrees
MEAN: 84.0 degrees
Highest Temperature: 101 degrees
Lowest Temperature: 65 degrees
August Rainfall: 3.05"
Summer Rainfall: 7.91"
2010 Precipitation: 29.04"

Roanoke, Virginia - Elevation 1175 feet
Average Daily MAX: 86.4 degrees
Average Daily MIN: 67.9 degrees
MEAN: 77.2 degrees
Highest Temperature: 97 degrees
Lowest Temperature: 61 degrees
August Rainfall: 5.00"
Summer Rainfall: 12.01"
2010 Precipitation: 29.35"

Richmond, Va., ( State Capitol ) - Elevation 167 feet
Average Daily MAX: 89.9 degrees
Average Daily MIN: 69.9 degrees
MEAN: 79.9 degrees
Highest Temperature: 98 degrees
Lowest Temperature: 64 degrees
August Rainfall: 3.92"
Summer Rainfall: 5.93"
( 3rd driest Summer on Record )
2010 Precipitation: 22.73"

August 31, 2010
Morning Inversion - Powell Valley of HKL
Photograph by Roddy Addington - © All Rights Reserved.


Temperature Statistics
For Summer 2010
( June-August )

High Knob Lake Basin
Swallowtail Butterfly's - August 2010
Photograph by Roddy Addington - © All Rights Reserved.

Clintwood 1 W - Elevation 1560 feet
Average Daily MAX: 83.2 degrees
Average Daily MIN: 61.9 degrees
Summer MEAN: 72.6 degrees

Breaks Interstate Park - Elevation 1893 feet
Average Daily MAX: 79.0 degrees
Average Daily MIN: 63.1 degrees
Summer MEAN: 71.0 degrees

City of Norton - Elevation 2141 feet
Average Daily MAX: 82.6 degrees
Average Daily MIN: 59.5 degrees
Summer MEAN: 71.0 degrees
Highest Temperature: 91 degrees
Lowest Temperature: 44 degrees
Number of days at or above 90: 2

Nora 4 SSE - Elevation 2650 feet
Average Daily MAX: 80.7 degrees
Average Daily MIN: 64.8 degrees
Summer MEAN: 72.8 degrees
Highest Temperature: 91 degrees
Lowest Temperature: 54 degrees
Number of days at or above 90: 2

Burkes Garden - Elevation 3068 feet
Average Daily MAX: 79.6 degrees
Average Daily MIN: 57.1 degrees
Summer MEAN: 68.4 degrees
Highest Temperature: 88 degrees
Lowest Temperature: 39 degrees

In the High Knob highcountry mean summer temperatures varied from 70s by day to 50s at night to generate averages in the 60s for most locations.

[ An abundance of summer rainfall and clouds, as highlighted above, helping hold daytime temperatures down while making nights milder than average ( but still comfortable across the massif relative to those places experiencing record summer heat as highlighted below ) ].

As noted by Breaks Interstate Park above, with a shady northern exposure, there were some exceptions as the coolest mean daily maximums occurred on north slopes across a broad elevation range ( the coolest locations generally being on N-NE sides of high valleys, with nocturnal cold air drainage also acting to reduce daily means amid these lofty basins ).

Coolness was relative, as for nearly all locations and elevations it was a summer of above average to even record level heat ( record heat being widespread with dryness in the Great Valley of eastern Tennessee and across much of Virginia to the east and southeast of the Clinch-Powell basins ).


( June-August of 2010 )
Hottest Summer On Record
Across Great Valley of East Tennessee

It is now official that Summer 2010 was the hottest of all-time in the Great Valley of eastern Tennessee ( while linked to a dry feedback this is still very impressive! ).

Tri-Cities ( TRI )
Mean Summer Temperature: 77.3 degrees
( Warmest since record keeping began in 1934 )

Knoxville ( TYS )
Mean Summer Temperature: 81.0 degrees
( Beat out the 80.1 degree mean in Summer 1936 )

Chattanooga ( CHA )
Mean Summer Temperature: 83.0 degrees
( Beat out 82.0 degrees for Summer 1993 )

Although summer rainfall was not nearly the lowest on record, especially at TRI thanks to a wet turn in August, much of Summer 2010 was dry to contribute to these impressive levels of heat!


( June-August of 2010 )
Hottest Summer On Record
Virginia & District of Columbia

Summer 2010 was also the hottest across much of Virginia, and in the National Capitol district.

Blacksburg
Mean Summer Temperature: 72.9 degrees
( Record keeping began in 1952 )

Bluefield
Mean Summer Temperature: 74.5 degrees
( Record keeping began in 1959 )

Roanoke
Mean Summer Temperature: 78.2 degrees
( Record keeping began in 1912 )

Danville
Mean Summer Temperature: 80.0 degrees
( Record keeping began in 1948 )

Norfolk
Mean Summer Temperature: 81.1 degrees
( Previous record was 80.0 degrees in Summer 1994 )

Richmond
Mean Summer Temperature: 81.3 degrees
( Beat out the 79.6 degrees in Summer 1900 )

Washington D.C.
Mean Summer Temperature: 81.3 degrees
( Record keeping began in 1872 )

One of the hottest places in Virginia during Summer 2010 was Hopewell, in Prince George County, with a blazing mean of 82.6 degrees via 92.7 degrees by day and 72.4 degrees at night. 

Driving these amazing records at so many places has been a record number of days above 90 degrees, from TRI to Washington D.C., with the mean summer max of 90.2 degrees in the Nation's Capitol marking the first time since 1872 that the average daily high for the entire summer has been above 90.

[ More than 50 days of 90+ degree heat became an all-time record for TRI, with Washinton D.C. also on pace to break its all-time number of 90 degree days in a year ( 67 set in 1980 ) ].

However, the most common denominator was record warm nights at nearly all locations setting new marks for mean summer temperatures!

[ Mean summer MINS were unusually warm across the High Knob Landform, with only higher valleys and the highest crestlines having average lows in the 50s ].

August 2010
High Knob Lake Basin
Swallowtail's and Milkweed ( Asclepias spp. )
Photograph by Roddy Addington - © All Rights Reserved.


Regional Precipitation Statistics
For Summer & Year of 2010

[ Note:  All National Weather Service Cooperative data listed below is to be considered preliminary until its officially certified by the National Climatic Data Center ( NCDC ).
Errors may exist.  Chosen data points are only for the general illustration of regional precipitation variations. ]. 

Virginia & District of Columbia

Woodstock 2 NE
August Rainfall: 1.36"
Summer Rainfall: 3.78"
May-August Rain: 6.53"
2010 Precipitation: 17.70"
( 1 day missing in July )

Dale Enterprise
August Rainfall: 2.26"
Summer Rainfall: 5.57"
May-August Rain: 8.17"
2010 Precipitation: 18.45"

Madison
August Rainfall: 1.54"
Summer Rainfall: 4.26"
May-August Rain: 7.34"
2010 Precipitation: 20.58"

Washington D.C. - National Airport
August Rainfall: 2.59"
Summer Rainfall: 9.63"
May-August Rain: 12.03"
2010 Precipitation: 21.36"

Orange
( Piedmont Research Station )
August Rainfall: 2.59"
Summer Rainfall: 6.49"
May-August Rain: 9.56"
2010 Precipitation: 21.41"

Staunton Water Plant
August Rainfall: 2.53"
Summer Rainfall: 7.43"
May-August Rain: 10.84"
2010 Precipitation: 21.81"

Pulaski 2 E
August Rainfall: 4.07"
Summer Rainfall: 7.24"
May-August Rain: 9.52"
2010 Precipitation: 21.99"

Edinburg
August Rainfall: 2.28"
Summer Rainfall: 9.66"
May-August Rain: 12.12"
2010 Precipitation: 22.04"

Charlottesville
August Rainfall: 2.36"
Summer Rainfall: 6.08"
May-August Rain: 9.65"
2010 Precipitation: 22.45"

Richmond
August Rainfall: 3.92"
Summer Rainfall: 5.93"
May-August Rain: 8.55"
2010 Precipitation: 22.73"

Winchester
August Rainfall: 1.49"
Summer Rainfall: 6.36"
May-August Rain: 9.11"
2010 Precipitation: 23.28"

Warsaw 2 NW
August Rainfall: 4.12"
Summer Rainfall: 6.97"
May-August Rain: 8.55"
2010 Precipitation: 23.35"

Gathright Dam
August Rainfall: 3.70"
Summer Rainfall: 7.73"
May-August Rain: 12.78"
2010 Precipitation: 23.44"

Covington Filter Plant
August Rainfall: 2.82"
Summer Rainfall: 8.51"
May-August Rain: 12.56"
2010 Precipitation: 23.67"

Eastville
August Rainfall: 3.40"
Summer Rainfall: 8.04"
May-August Rain: 10.54"
2010 Precipitation: 24.66"
( 2 days missing June / 1 day July )

Suffolk Lake Kilby
August Rainfall: 2.44"
Summer Rainfall: 7.16"
May-August Rain: 10.93"
2010 Precipitation: 24.91"

Shenandoah 1.4 N
August Rainfall: 3.24"
Summer Rainfall: 12.55"
May-August Rain: 15.07"
2010 Precipitation: 25.61"
( 4 days missing during year )

Lexington
August Rainfall: 1.73"
Summer Rainfall: 9.32"
May-August Rain: 13.20"
2010 Precipitation: 25.67"

Christiansburg
August Rainfall: 4.85"
Summer Rainfall: 9.19"
May-August Rain: 14.33"
2010 Precipitation: 25.77"

Louisa
August Rainfall: 2.79"
Summer Rainfall: 8.17"
May-August Rain: 12.83"
2010 Precipitation: 25.79"

Buena Vista
August Rainfall: 4.02"
Summer Rainfall: 11.08"
May-August Rain: 13.64"
2010 Precipitation: 25.91"

West Point 2 NW
August Rainfall: 2.26"
Summer Rainfall: 6.82"
May-August Rain: 9.88"
2010 Precipitation: 25.97"

Williamsburg 2 N
August Rainfall: 2.34"
Summer Rainfall: 7.38"
May-August Rain: 10.28"
2010 Precipitation: 26.22"

Buckingham
August Rainfall: 3.54"
Summer Rainfall: 6.79"
May-August Rain: 12.77"
2010 Precipitation: 26.37"

Abingdon 3 S
August Rainfall: 4.48"
Summer Rainfall: 11.54"
May-August Rain: 14.69"
2010 Precipitation: 26.47"
( 4 missing days during year )

Clifton Forge RAWS
( U.S. Forest Service )
August Rainfall: 2.16"
Summer Rainfall: 8.02"
May-August Rain: 14.78"
2010 Precipitation: 26.56"

Washington D.C. - Dulles Airport
August Rainfall: 4.42"
Summer Rainfall: 9.88"
May-August Rain: 15.30"
2010 Precipitation: 26.59"

Luray 5 E
August Rainfall: 3.75"
Summer Rainfall: 10.31"
May-August Rain: 13.59"
2010 Precipitation: 26.80"

Somerset
August Rainfall: 2.63"
Summer Rainfall: 8.00"
May-August Rain: 12.57"
2010 Precipitation: 26.90"

Hopewell
August Rainfall: 5.79"
Summer Rainfall: 9.48"
May-August Rain: 14.27"
2010 Precipitation: 27.44"

Wallops Island
August Rainfall: 7.78"
Summer Rainfall: 11.31"
May-August Rain: 13.31"
2010 Precipitation: 27.57"

Front Royal
August Rainfall: 4.39"
Summer Rainfall: 8.15"
May-August Rain: 11.32"
2010 Precipitation: 27.66"
( 1 day missing July )

Bland
August Rainfall: 4.62"
Summer Rainfall: 11.48"
May-August Rain: 15.35"
2010 Precipitation: 27.76"
( 5 days missing during year )

Blacksburg
August Rainfall: 5.09"
Summer Rainfall: 10.90"
May-August Rain: 15.79"
2010 Precipitation: 27.81"

Danville
August Rainfall: 5.52"
Summer Rainfall: 9.81"
May-August Rain: 13.83"
2010 Precipitation: 27.86"

Wytheville 1 S
August Rainfall: 6.33"
Summer Rainfall: 12.44"
May-August Rain: 15.17"
2010 Precipitation: 28.05"
( 1 day missing in May )

Appomattox
August Rainfall: 5.41"
Summer Rainfall: 10.59"
May-August Rain: 16.01"
2010 Precipitation: 28.16"

Glasgow 1 SE
August Rainfall: 3.73"
Summer Rainfall: 8.17"
May-August Rain: 11.16"
2010 Precipitation: 28.19"

Kerrs Creek 6 WNW
August Rainfall: 2.75"
Summer Rainfall: 12.28"
May-August Rain: 16.78"
2010 Precipitation: 28.41"

Martinsville Filter Plant
August Rainfall: 4.99"
Summer Rainfall: 8.98"
May-August Rain: 12.62"
2010 Precipitation: 28.52"
( 1 day missing in June )

New Castle RAWS
( U.S. Forest Service )
August Rainfall: 6.35"
Summer Rainfall: 12.02"
May-August Rain: 15.82"
2010 Precipitation: 28.98"

Copper Hill
August Rainfall: 4.44"
Summer Rainfall: 9.79"
May-August Rain: 15.00"
2010 Precipitation: 29.08"

Roanoke
August Rainfall: 5.00"
Summer Rainfall: 12.01"
May-August Rain: 17.36"
2010 Precipitation: 29.35"

Mendota 1.6 SW
August Rainfall: 6.49"
Summer Rainfall: 15.20"
May-August Rain: 18.44"
2010 Precipitation: 29.82"

Marion 4.4 WSW
August Rainfall: 5.94"
Summer Rainfall: 14.79"
May-August Rain: 18.67"
2010 Precipitation: 30.70"
( 1 day missing in May )

Independence 2.2 E
August Rainfall: 9.83"
Summer Rainfall: 14.95"
May-August Rain: 18.82"
2010 Precipitation: 31.46"
( 6 days missing during year )

Lebanon
August Rainfall: 6.85"
Summer Rainfall: 14.46"
May-August Rain: 18.78"
2010 Precipitation: 31.54"

Clintwood
August Rainfall: 3.73"
Summer Rainfall: 13.06"
May-August Rain: 18.82"
2010 Precipitation: 31.97"

Grundy
August Rainfall: 2.80"
Summer Rainfall: 14.44"
May-August Rain: 20.46"
2010 Precipitation: 32.03"
( 1 day missing in May )

Breaks Interstate Park
August Rainfall: 1.65"
Summer Rainfall: 13.33"
May-August Rain: 18.53"
2010 Precipitation: 32.24"
( 1 day missing in May )

Lynchburg
August Rainfall: 6.53"
Summer Rainfall: 12.55"
May-August Rain: 17.11"
2010 Precipitation: 32.27"

North Fork of Pound Dam
August Rainfall: 4.07"
Summer Rainfall: 14.07"
May-August Rain: 20.05"
2010 Precipitation: 32.58"

Richlands
August Rainfall: 5.86"
Summer Rainfall: 17.26"
May-August Rain: 21.16"
2010 Precipitation: 32.71"

Norfolk
August Rainfall: 3.59"
Summer Rainfall: 13.19"
May-August Rain: 17.79"
2010 Precipitation: 32.82"

Holcomb Rock
August Rainfall: 6.49"
Summer Rainfall: 12.59"
May-August Rain: 17.39"
2010 Precipitation: 33.55"
( 1 day missing in May )

Wise RAWS
( U.S. Forest Service )
August Rainfall: 6.02"
Summer Rainfall: 11.71"
May-August Rain: 20.39"
2010 Precipitation: 33.65"

Nora 4 SSE
August Rainfall: 5.95"
Summer Rainfall: 14.36"
May-August Rain: 23.07"
2010 Precipitation: 34.42"

Saltville 1 N
August Rainfall: 7.45"
Summer Rainfall: 18.06"
May-August Rain: 23.38"
2010 Precipitation: 34.86"
( 2 days missing June / 3 days August )

Meadows of Dan 4.5 SW
August Rainfall: 6.66"
Summer Rainfall: 14.51"
May-August Rain: 19.79"
2010 Precipitation: 35.74"
( 1 day missing in May )

Burkes Garden
August Rainfall: 6.57"
Summer Rainfall: 14.39"
May-August Rain: 21.04"
2010 Precipitation: 36.06"

Pennington Gap
August Rainfall: 5.97"
Summer Rainfall: 13.84"
May-August Rain: 19.88"
2010 Precipitation: 36.50"
( 6 days missing during year )

Woolwine
August Rainfall: 6.63"
Summer Rainfall: 13.29"
May-August Rain: 17.49"
2010 Precipitation: 36.56"

Appalachia Lake Water Plant
August Rainfall: 6.66"
Summer Rainfall: 17.75"
May-August Rain: 23.85"
2010 Precipitation: 38.19"

Norton Water Plant
August Rainfall: 7.65"
Summer Rainfall: 15.76"
May-August Rain: 24.36"
2010 Precipitation: 39.13"

Meadows of Dan 5 SW
August Rainfall: 7.69"
Summer Rainfall: 15.13"
May-August Rain: 20.82"
2010 Precipitation: 39.46"
( 11 days missing June-July )

Stuart
August Rainfall: 10.24"
Summer Rainfall: 17.22"
May-August Rain: 22.49"
2010 Precipitation: 39.51"
( 9 days missing June-August )

Robinson Knob of High Knob Massif
August Rainfall: 8.82"
Summer Rainfall: 17.51"
May-August Rain: 23.03"
2010 Precipitation: 39.95" ( M )

Big Stone Gap Water Plant
( South Fork Gorge of High Knob Massif )
August Rainfall: 9.57"
Summer Rainfall: 19.50"
May-August Rain: 25.63"
2010 Precipitation: 40.22"

Big Cherry Dam of High Knob Massif
August Rainfall: 8.91"
Summer Rainfall: 22.71"
May-August Rain: 29.70" ( M )
2010 Precipitation: 48.48" ( M )

( M ) - Denotes missing data during the year from evaporation and losses in snowfall.

High Knob Lake Basin - August 2010
Eastern Tiger Swallowtails ( Papilio glaucus )
Photograph by Roddy Addington - © All Rights Reserved.


West Virginia

Alderson
August Rainfall: 2.88"
Summer Rainfall: 6.28"
May-August Rain: 10.56"
2010 Precipitation: 21.82"

Bluestone Lake
August Rainfall: 2.71"
Summer Rainfall: 6.94"
May-August Rain: 12.11"
2010 Precipitation: 22.85"

Union 3 SSE
August Rainfall: 3.42"
Summer Rainfall: 9.71"
May-August Rain: 13.37"
2010 Precipitation: 22.92"

Lost River
August Rainfall: 2.10"
Summer Rainfall: 7.53"
May-August Rain: 11.26"
2010 Precipitation: 23.06"
( 2 days missing August / 2 days June )

Keyser 2 SSW
August Rainfall: 1.59"
Summer Rainfall: 6.24"
May-August Rain: 11.45"
2010 Precipitation: 23.24"

Martinsburg
August Rainfall: 2.03"
Summer Rainfall: 5.65"
May-August Rain: 10.09"
2010 Precipitation: 24.23"

White Sulphur Springs
August Rainfall: 3.46"
Summer Rainfall: 10.80"
May-August Rain: 14.26"
2010 Precipitation: 25.26"

Bartow 1 S
August Rainfall: 4.85"
Summer Rainfall: 10.80"
May-August Rain: 15.38"
2010 Precipitation: 25.33"
( 3 days missing during year )

Lewisburg 3 N
August Rainfall: 3.40"
Summer Rainfall: 9.92"
May-August Rainfall: 13.65"
2010 Precipitation: 25.58"

Albright
August Rainfall: 1.57"
Summer Rainfall: 10.05"
May-August Rain: 14.56"
2010 Precipitation: 27.07"

Elkins
August Rainfall: 4.86"
Summer Rainfall: 14.49"
May-August Rain: 19.09"
2010 Precipitation: 27.71"

Glenville
August Rainfall: 3.37"
Summer Rainfall: 11.70"
May-August Rain: 16.49"
2010 Precipitation: 28.83"
( 3 days missing during Summer )

Buckeye
August Rainfall: 2.99"
Summer Rainfall: 8.57"
May-August Rain: 16.15"
2010 Precipitation: 28.86"
( 1 day missing in August )

Parkersburg
August Rainfall: 1.96"
Summer Rainfall: 13.64"
May-August Rain: 21.36"
2010 Precipitation: 29.72"

Gassaway
August Rainfall: 2.50"
Summer Rainfall: 12.88"
May-August Rain: 17.51"
2010 Precipitation: 29.76"
( 1 day missing July / 1 day June )

Buckhannon
August Rainfall: 4.53"
Summer Rainfall: 14.40"
May-August Rain: 19.13"
2010 Precipitation: 30.11"
( 1 day missing August / 5 days June )

Marlinton
August Rainfall: 2.97"
Summer Rainfall: 8.93"
May-August Rain: 18.48"
2010 Precipitation: 30.80"

Huntington
August Rainfall: 2.51"
Summer Rainfall: 13.52"
May-August Rain: 20.68"
2010 Precipitation: 31.21"

Bluefield
August Rainfall: 4.22"
Summer Rainfall: 13.79"
May-August Rain: 18.27"
2010 Precipitation: 32.17"

Sutton Lake
August Rainfall: 3.25"
Summer Rainfall: 15.01"
May-August Rain: 19.95"
2010 Precipitation: 32.21"
( 1 day missing August / 1 day July )

Berwind RAWS
( U.S. Forest Service )
August Rainfall: 3.67"
Summer Rainfall: 14.06"
May-August Rain: 20.26"
2010 Precipitation: 33.09"

Beckley
August Rainfall: 2.71"
Summer Rainfall: 12.85"
May-August Rain: 20.32"
2010 Precipitation: 33.17"

McRoss 3 E
August Rainfall: 4.03"
Summer Rainfall: 12.51"
May-August Rain: 18.78"
2010 Precipitation: 33.17"

Bayard
August Rainfall: 2.51"
Summer Rainfall: 11.76"
May-August Rain: 16.03"
2010 Precipitation: 33.81"
( 3 days missing during summer )

Charleston
August Rainfall: 3.30"
Summer Rainfall: 14.59"
May-August Rain: 22.60"
2010 Precipitation: 34.22"

Summersville Lake
August Rainfall: 3.95"
Summer Rainfall: 16.37"
May-August Rain: 22.34"
2010 Precipitation: 35.18"
( 5 days missing during year )

Davis 3 SE
( Canaan Mountain )
August Rainfall: 3.60"
Summer Rainfall: 11.84"
May-August Rain: 16.74"
2010 Precipitation: 35.92"

R.d. Bailey Lake
August Rainfall: 3.07"
Summer Rainfall: 19.17"
May-August Rain: 24.26"
2010 Precipitation: 36.58"
( 1 day missing August / 3 days July )

Hacker Valley
August Rainfall: 3.26"
Summer Rainfall: 17.02"
May-August Rain: 22.58"
2010 Precipitation: 37.89"
( 3 days missing June / 5 days August )

Rock Cave 2 NE
August Rainfall: 5.09"
Summer Rainfall: 17.28"
May-August Rain: 23.25"
2010 Precipitation: 38.46"
( 6 days missing in August )

Terra Alta
August Rainfall: 2.89"
Summer Rainfall: 15.76"
May-August Rain: 21.99"
2010 Precipitation: 39.55"

Snowshoe Mountain
August Rainfall: 5.75"
Summer Rainfall: 17.51"
May-August Rain: 26.40"
2010 Precipitation: 48.22"
( 3 days missing during year )


August 29, 2010
Pike County, Kentucky
Little Boy & Friends - Fishtrap Lake
Photograph by Roddy Addington - © All Rights Reserved.


Kentucky

Paintsville 1 E
August Rainfall: 2.60"
Summer Rainfall: 13.38"
May-August Rain: 17.91"
2010 Precipitation: 27.71"
( 1 day missing in August )

Booneville 12 SW
August Rainfall: 5.75"
Summer Rainfall: 12.64"
May-August Rain: 17.17"
2010 Precipitation: 28.30"

Charley 2 SW
August Rainfall: 3.33"
Summer Rainfall: 14.10"
May-August Rain: 19.11"
2010 Precipitation: 28.80"

Lexington
August Rainfall: 0.58"
Summer Rainfall: 11.23"
May-August Rain: 21.18"
2010 Precipitation: 29.24"

Carr Fork Lake
August Rainfall: 4.61"
Summer Rainfall: 13.14"
May-August Rain: 18.24"
2010 Precipitation: 30.05"
( 5 missing days during year )

London
August Rainfall: 6.03"
Summer Rainfall: 14.48"
May-August Rain: 19.97"
2010 Precipitation: 32.74"

Jackson
August Rainfall: 3.51"
Summer Rainfall: 12.45"
May-August Rain: 20.37"
2010 Precipitation: 32.79"

Skyline 1 SE
August Rainfall: 4.80"
Summer Rainfall: 13.69"
May-August Rain: 20.65"
2010 Precipitation: 32.88"

Buckhorn Lake State Park
August Rainfall: 7.92"
Summer Rainfall: 16.10"
May-August Rain: 20.21"
2010 Precipitation: 33.33"

Barbourville
August Rainfall: 2.33"
Summer Rainfall: 11.33"
May-August Rain: 16.27"
2010 Precipitation: 33.36"

Hazard Water Works
August Rainfall: 6.98"
Summer Rainfall: 17.97"
May-August Rain: 24.06"
2010 Precipitation: 35.99"
( 3 days missing during year )

Oneida
August Rainfall: 9.69"
Summer Rainfall: 19.63"
May-August Rain: 25.18"
2010 Precipitation: 38.46"

Stearns 2 S
August Rainfall: 7.80"
Summer Rainfall: 19.69"
May-August Rain: 27.11"
2010 Precipitation: 40.94"


August 29, 2010
Pine Mountain - SE Kentucky
Nature Scene Along Little Shepherd Trail
Photograph by Roddy Addington - © All Rights Reserved.


Tennessee

Tri-Cities
August Rainfall: 6.26"
Summer Rainfall: 10.80"
May-August Rain: 13.38"
2010 Precipitation: 23.50"

Kingsport
August Rainfall: 6.93"
Summer Rainfall: 12.21"
May-August Rain: 16.02"
2010 Precipitation: 26.29"
( 3 days missing during summer )

Newport 1 NW
August Rainfall: 4.54"
Summer Rainfall: 11.75"
May-August Rain: 16.68"
2010 Precipitation: 26.65"

Knoxville
August Rainfall: 2.80"
Summer Rainfall: 9.94"
May-August Rain: 14.16"
2010 Precipitation: 28.54"

Chattanooga
August Rainfall: 3.05"
Summer Rainfall: 7.91"
May-August Rain: 13.29"
2010 Precipitation: 29.04"

Pikeville
August Rainfall: 1.54"
Summer Rainfall: 8.84"
May-August Rain: 13.27"
2010 Precipitation: 29.25"

Tazewell
August Rainfall: 5.75"
Summer Rainfall: 14.60"
May-August Rain: 21.75"
2010 Precipitation: 36.55"

Lancing 6 NW
August Rainfall: 7.02"
Summer Rainfall: 15.79"
May-August Rain: 22.71"
2010 Precipitation: 38.94"

Monterey
August Rainfall: 6.04"
Summer Rainfall: 15.58"
May-August Rain: 23.48"
2010 Precipitation: 42.04"

Norris
August Rainfall: 6.09"
Summer Rainfall: 16.43"
May-August Rain: 24.99"
2010 Precipitation: 42.62"
( 1 day missing August / 1 day July )

Monteagle
August Rainfall: 7.07"
Summer Rainfall: 16.32"
May-August Rain: 21.04"
2010 Precipitation: 43.22"

Mount LeConte
August Rainfall: 6.64"
Summer Rainfall: 24.06"
May-August Rain: 30.79"
2010 Precipitation: 53.59"
( 1 day missing in July )


High Knob Lake Basin
Mushrooms Galore - August 2010
Photograph by Roddy Addington - © All Rights Reserved.


North Carolina

Raleigh-Durham
August Rainfall: 3.06"
Summer Rainfall: 8.06"
May-August Rain: 13.06"
2010 Precipitation: 24.15"

Charlotte
August Rainfall: 4.75"
Summer Rainfall: 10.12"
May-August Rain: 13.49"
2010 Precipitation: 27.97"

Asheville
August Rainfall: 3.47"
Summer Rainfall: 8.76"
May-August Rain: 13.65"
2010 Precipitation: 30.42"

Hickory
August Rainfall: 3.34"
Summer Rainfall: 10.29"
May-August Rain: 13.70"
2010 Precipitation: 30.58"

Jefferson 2 E
August Rainfall: 5.30"
Summer Rainfall: 9.19"
May-August Rain: 15.05"
2010 Precipitation: 31.50"
( 6 days missing during summer )

Spruce Pine 2 NE
August Rainfall: 6.95"
Summer Rainfall: 14.89"
May-August Rain: 18.08"
2010 Precipitation: 33.06"

Beech Mountain
August Rainfall: 4.67"
Summer Rainfall: 12.28"
May-August Rain: 15.79"
2010 Precipitation: 34.31"

Boone 1 SE
August Rainfall: 5.68"
Summer Rainfall: 11.31"
May-August Rain: 16.67"
2010 Precipitation: 36.73"

Transou
August Rainfall: 7.59"
Summer Rainfall: 18.64"
May-August Rain: 22.46"
2010 Precipitation: 41.40"

Mount Mitchell
August Rainfall: 3.95"
Summer Rainfall: 11.57"
May-August Rain: 16.56"
2010 Precipitation: 44.92"
( 1 day missing in July & 1 day in August )

Grandfather Mountain
August Rainfall: 9.47"
Summer Rainfall: 16.40"
May-August Rain: 20.87"
2010 Precipitation: 49.60"

[ Note:  Precipitation may or may not have occurred at any site listed in the states above with missing days ].

Morning Inversion - August 31, 2010
Interior Ridges in Powell Valley of HKL
Photograph by Roddy Addington - © All Rights Reserved.

For a brief review of Summer 2009 please reference:



Climatology of September

Historic Temperatures

High Knob Lake Basin
Fungi Flourish In Late Summer 2010
Photograph by Roddy Addington - © All Rights Reserved.

The dawn of September marks the beginning of meteorological autumn, with weather changes that typically become increasingly pronounced as the month passes and summer fades.

September often brings the first frost of the new cold season to mid-upper elevations, as early colors of autumn begin to decorate the High Knob highcountry.

For a review of September 2009 reference:

In fact, it can get down right COLD
during some mornings!

Top Ten Coldest September Nights On Record
Wise 1 SE and Wise 3 E
Elevation: 2549 to 2560 feet
Record Period: 1955 to 2009

31 degrees....September 21, 1962
31 degrees...September 23, 1967
31 degrees...September 30, 1967
32 degrees...September 24, 1989
32 degrees...September 29, 1969
33 degrees...September 14, 1964
33 degrees....September 16, 1961
33 degrees...September 25, 1967
34 degrees...September 11, 1964
34 degrees...September 15, 1964 

Coldest temperatures are typically observed along the highest ridges, and within mid to upper elevation basins subjected to cold air drainage.

Top Ten Coldest September Nights On Record
Burkes Garden Basin
Elevation: 3068 to 3300 feet
Record Period: 1896 to 2009

21 degrees...September 24, 1983
24 degrees...September 29, 1942
25 degrees...September 18, 1943
25 degrees...September 21, 1962
25 degrees...September 25, 1903
25 degrees...September 30, 1908
26 degrees...September 19, 1929
26 degrees...September 20, 1916
26 degrees...September 22, 1918
27 degrees.....September 6, 1924

While the first true cold front of Autumn 2010 looks to arrive in time for the Labor Day weekend as Hurricane Earl helps reinforce an upper trough digging south across the Great Lakes, the first few days of the month will feature large day to night temperature spreads as subsidence around Earl dries the air over the southern Appalachians.

[ Setting the stage for cool nights in mid-upper elevation valleys and unseasonably warm days ].

Western Atlantic Ocean
1020 hours on August 29, 2010
Danielle ( top ) and Earl ( bottom )
 Imagery Courtesy of NASA

[ Feathery outflow from Hurricane Danielle is seen as she pulls away from North America above, with thin cloud filaments connecting with developing Hurricane Earl in the Caribbean ].

September is climatologically the peak of Atlantic hurricane activity, with subsidence induced compressional warming a feature that builds late season surges of heat around the peripheries of these great, warm core monsters.

Top Ten Hottest September Days On Record
Wise 1 SE and Wise 3 E
Elevation: 2549 to 2560 feet
Record Period: 1955 to 2009

90 degrees.....September 1, 1993
90 degrees...September 14, 1998
89 degrees.....September 2, 1957
89 degrees.....September 3, 1999
89 degrees.....September 5, 1975
89 degrees.....September 7, 1990
89 degrees...September 10, 1983
89 degrees...September 13, 1998
88 degrees.....September 4, 1999
88 degrees...September 15, 1998 

[ Hurricane Emily made her closest, curving approach to the Outer Banks of North Carolina on September 1, 1993 in correlation to a 90 degree MAX along the western Appalachians in Wise ].

110 air miles NE of San Juan, Puerto Rico
Lat 19.3 degrees North / Long 64.7 degrees West
Hurricane Earl - August 30, 2010
Photograph by Douglas Wheelock - © All Rights Reserved.


September Rainfall Linked To
Sub-Tropics & Tropics

Climatology reveals that September rainfall amounts across The High Knob Landform are highly linked, or correlated, to what is happening in lower latitudes, with great variations from one year to the next being common.

[ This correlation generally occurring prior to the larger scale cyclogenesis events which arise with increasing frequency as north to south temperature gradients increase during mid-late autumn and winter ( i.e., the main orographic forcing season ) ].

A review of recent years illustrates this well, with September 2009 featuring 9.00" to 11.00"+ of rainfall across the High Knob Massif as abundant moisture streamed into the southern Appalachians from an atypically active sub-tropical jet stream ( a rather unusual setting for so early in an autumn, with a distinct lack of organized tropical systems ).

High Knob Lake Basin
Swallowtail Butterfly on ( Eupatorium spp. )
Photograph by Roddy Addington - © All Rights Reserved.

September 2008 featured only 2.50" to 3.00"+ of rain across the High Knob Massif area, as an enhanced amount of sinking air ruled between tropical cyclones which tracked both west and east of the southern Appalachians.

[ IKE being the big ticket storm of September 2008 that pounded a corridor from Houston to Chicago with flooding rains, while causing damaging winds of 70-80+ miles per hour across northern Kentucky and the Ohio Valley ].

September 2007 was analogous, as tropical cyclone tracks stayed well east and south of the southern Appalachians with only 2.00" to 3.00" of rainfall across the High Knob Massif.

High Knob Massif
Pipevine Swallowtail ( Battus philenor )
Working Brilliant Milkweed ( Asclepias spp. )
Photograph by Roddy Addington - © All Rights Reserved.

September 2006 was much different, as a combination of remnant tropical moisture and several deep, moist southwesterly flow frontal events generated 7.00" to 10.00"+ of rain across the High Knob Massif.

September 2004 was a big ditto, to an even greater degree, as remnants of hurricanes Frances, Ivan, and Jeanne all spread rich, tropical moisture across the southern Appalachians.  Rainfall totals reached 17.00"+ within Big Cherry Basin of the High Knob Massif.

So a review of only a few years illustrates well how September conditions are impacted by what's going on in the sub-tropics and tropics, with September 2010 being to date ruled by sinking air adjacent to the Atlantic "hurricane highway."

[ In general, as heavy 1.50"-3.00"+ rainfall amounts from the remnants of Hermine soaked southwestern portions of the HKL during September 11-12, from western Lee County & Cumberland Gap National Historical Park into the I-75 corridor of northern Tennessee and southern Kentucky ].


( Updated: September 15, 2010 )
Mid-September Climate Update

High Knob Lake Special Biological Area
Unusual Mushroom Form - High Knob Massif
Photograph by Roddy Addington - © All Rights Reserved.

The first half of September 2010 has featured near average temps within the High Knob Massif area, with unseasonably warm days being offset by cool nights.

September 1-15, 2010
City of Norton - Elevation 2141 feet
Average Daily MAX: 78.1 degrees
Average Daily MIN: 46.4 degrees
MEAN: 62.2 degrees
Rainfall: 1.50"
( 40.63" in 2011 )



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