Friday, November 29, 2013

White Thanksgiving Closes November 2013


Mother Nature signaled development of a major winter storm with dramatic morning skies above the Cumberlands on November 25.

November 25, 2013
Along The Tennessee Valley Divide
Prelude To An Early Winter Storm
Photograph by Wayne Riner - © All Rights Reserved.

Wayne Riner Photograph Thoughts...
"The vertical shaft of light is caused by light 
from the rising sun hitting ice crystals in the atmosphere."

Above the Powell River Basin
Red Sky In The Morning - All Take Warning!
Photograph by Harold L. Jerrell - © All Rights Reserved.


A general 0.5-1" of snow fell across Lee, Wise, northern Scott and Dickenson counties during evening hours of November 25, but melted away with rain into morning hours of November 26.

November 25, 2013
Eagle Knob of High Knob Massif
Snow Covered Roads & Ground At 9:50 PM
Photograph by Steve Blankenbecler - © All Rights Reserved.

By the time rain changed back to sleet and snow, during the 11 PM-Midnight hour of November 26, 
a general 1.50" to 2.50" of rain had accumulated.

12:04 AM on November 27, 2013
Doppler Storm Total Precipitation Estimate
Graphic Courtesy of Plymouth State Weather Center

Although the winter storm ended up being less severe than originally predicted it still produced bad conditions and enough snow to make lovers of the "white stuff" generally happy campers 
( everyone can never be satisfied ).


White Thanksgiving 2013

Nora 4 SSE
November 28, 2013
Long Ridge of Tennessee Valley Divide
Idyllic Thanksgiving Holiday In The Highlands
Photograph by Wayne Riner - © All Rights Reserved.

Thanksgiving Morning
Snow Depths On The Ground

Clintwood 1 W: 3"
Observer - Wayne Browning

City of Norton Water Plant: 4"
Observers - Joe Carter & Bill Ballard

Nora 4 SSE: 4"
Observers - Wayne & Genevie Riner

High Chaparral of High Knob Massif: 6"
Observers - Joe & Darlene Fields

November 28, 2013
Crystal Clear & Cold - Thanksgiving Morning
Photograph by Wayne Riner - © All Rights Reserved.

Snowfall production came via three distinct 
periods forced by different mechanisms:

1 ).  Isentropic-WAA Snowfall Period
( Evening of November 25 )

Evaporation amid initially dry air allowed precipitation to develop as snow during evening hours of Nov 25, with mixed snow-sleet in late evening, as moist air was forced upward along sloping isentropic surfaces 
( from warm air into cold air ).

This was short-lived as Warm Air Advection ( WAA ) aloft overwhelmed cooling processes, with general 0.5" to 1" snowfall accumulations.


2 ).  System Snowfall Period
( Midnight to Sunrise of November 27 )

This was the critical storm period that posed the greatest threat for heavy wet snow and power outages.  It ended up under-preforming as phasing together of Polar and Sub-tropical Jet Stream energies was both slower and weaker than initially forecasted by models.

The best way to illustrate this is with 500 MB Height Anomalies of the ECMWF ( European ) Forecast Model.

ECMWF Initialization At 7:00 PM November 25

ECMWF Initialization At 7:00 AM November 26

ECMWF Initialization At 7:00 PM November 26

ECMWF Initialization At 7:00 AM November 27

Example Run of Many
( Forecast Made 48-Hours In Advance )
ECMWF Model Forecast For 7:00 AM November 27

Actual Phasing Occurred 6-12 Hrs Later
ECMWF Initialization At 7:00 PM November 27

Although the above might seem minor, to the trained eye it was a HUGE miss and made all the difference between an aggressive, heavy SYSTEM period of snow and only light-moderate snowfall.

The City of Norton exemplified this result with only 1.8" of total snow depth by 9:00 AM on November 27, atypically less than both Pound and Clintwood, as orographic forcing was also weaker during this time period of system snow.

A general 1-3" of System Snow 
accumulated across the area.

The Clinch, Powell, Holston, and Great Valleys of the Upper Tennessee River Basin received the bulk of their snow during this period, with small to no additional accumulations during the subsequent orographic period due to significant downsloping.


3 ).  Orographic - Upslope Snowfall Period
( Remainder of November 27 )

The orographic period of NW upslope flow snowfall was productive for the High Knob Massif area and allowed the City of Norton to make up for some of its losses during system snow via numerous intense snow squalls, some featuring near whiteout conditions for brief intervals.

7:00 PM November 26, 2013
ECMWF Model 850 MB Initialization

7:00 AM November 27, 2013
ECMWF Model 850 MB Initialization

7:00 AM November 27, 2013
ECMWF Model 850 MB Initialization

Bill Ballard measured 4" of snow depth at the Norton Water Plant by 4:00 PM November 27, with another intense squall just after that time.

Joe Carter measured 4" of depth at 9:00 AM Thanksgiving morning.  The storm total fall for the entire event was 5.0" ( when including evening snow of November 25 that melted after sticking ).

So the City of Norton got the bulk of its snowfall from upsloping after missing out on the heavier system snow.

Snow depths topped 4" in High Chaparral of the High Knob Massif by noon November 27, with locally intense squalls pushing depths to 6" by later November 27 ( storm total fall of 6.7" at 3300 feet ) as measured by observers Joe & Darlene Fields.

Melted water contents and reports indicated that the heaviest snow fell across the main crest zone, between Bowman Mountain and Powell Mountain, where blowing and local drifting occurred.

November 27, 2013 at 11:15 AM
Eagle Knob of High Knob Massif
Heavy Snow & Blowing Snow At 4189 feet
Photograph by Steve Blankenbecler - © All Rights Reserved.

Light snow & flurries were 
common between snow squalls.

November 27, 2013
Long Ridge of Tennessee Valley Divide
Wintry Day On The Mountain Farm In Late Autumn
Photograph by Wayne Riner - © All Rights Reserved.

NASA visible imagery during November 27 indicated a beautiful array of upslope cloud streamers and orographic gravity waves 
across the southern Appalachians following departure of higher altitude system clouds.


Time Series Of Visible Images

Click consecutively in picture viewer for motion

Lingering System or Dynamic Clouds
8:15 AM Local Time on November 27, 2013
NASA Visible Image At 1315 UTC November 27

8:45 AM Local Time on November 27, 2013
NASA Visible Image At 1345 UTC November 27

9:15 AM Local Time on November 27, 2013
NASA Visible Image At 1415 UTC November 27

9:45 AM Local Time on November 27, 2013
NASA Visible Image At 1445 UTC November 27

10:15 AM Local Time on November 27, 2013
NASA Visible Image At 1515 UTC November 27

Counties Overlayed
10:15 AM Local Time on November 27, 2013
NASA Visible Image At 1515 UTC November 27

11:02 AM Local Time on November 27, 2013
NASA Visible Image At 1602 UTC November 27

11:32 AM Local Time on November 27, 2013
NASA Visible Image At 1632 UTC November 27

12:32 PM Local Time on November 27, 2013
NASA Visible Image At 1732 UTC November 27

1:32 PM Local Time on November 27, 2013
NASA Visible Image At 1832 UTC November 27

2:02 PM Local Time on November 27, 2013
NASA Visible Image At 1902 UTC November 27

2:32 PM Local Time on November 27, 2013
NASA Visible Image At 1932 UTC November 27

Counties Overlayed
2:32 PM Local Time on November 27, 2013
NASA Visible Image At 1932 UTC November 27

Dramatic looking visible images were also a nice feature of Thanksgiving Day as snow blanketed much of the southern Appalachians, accentuating the large fold of the High Knob Massif and the open, rolling floor of the Great Valley.

9:02 AM Local Time on November 28, 2013
NASA Visible Image At 1402 UTC November 28

9:15 AM Local Time on November 28, 2013
NASA Visible Image At 1415 UTC November 28

Counties Overlayed
9:15 AM Local Time on November 28, 2013
NASA Visible Image At 1415 UTC November 28

9:32 AM Local Time on November 28, 2013
NASA Visible Image At 1432 UTC November 28

9:45 AM Local Time on November 28, 2013
NASA Visible Image At 1445 UTC November 28

10:15 AM Local Time on November 28, 2013
NASA Visible Image At 1515 UTC November 28

Another perspective from the JKL Sector

9:32 AM Local Time on November 28, 2013
NASA Visible Image At 1432 UTC November 28

Observe how snow shows up best on rolling-flat terrain verses folded topography which actually has more snow, in most cases, but is darker appearing.  The High Knob Massif is especially prominent and accentuated during such days ( as illustrated before on this website ).

Labels for Clouds, Locations, Snow
9:32 AM Local Time on November 28, 2013
NASA Visible Image At 1432 UTC November 28

9:45 AM Local Time on November 28, 2013
NASA Visible Image At 1445 UTC November 28

Observe the lack of snow across southwest portions of the Great Valley and in sections such as the Rogersville area of Hawkins County, Tn., which only had a "dusting."

10:15 AM Local Time on November 28, 2013
NASA Visible Image At 1515 UTC November 28


Climate Statistics
For November 2013

November 28, 2013
Along the Tennessee Valley Divide
Thanksgiving Day In The Snowy Woods
Photograph by Wayne Riner - © All Rights Reserved.

( Lower Elevations of Russell Fork Basin )
Clintwood 1 W - Elevation 1560 feet
Average Daily MAX: 51.6 degrees
Average Daily MIN: 25.4 degrees
MEAN: 38.5 degrees
Highest Temperature: 71 degrees
Lowest Temperature: 11 degrees
Total Snowfall: 4.7"
Total Precipitation: 3.52"
2013 Precipitation: 45.05"

( Northern Base of High Knob Massif )
City of Norton - Elevation 2141 feet
Average Daily MAX: 49.2 degrees
Average Daily MIN: 23.8 degrees
MEAN: 36.5 degrees
Highest Temperature: 68
Lowest Temperature: 8
Total Snowfall: 5.2"
Total Precipitation: 4.21"
2013 Precipitation: 55.12"

( Along the Tennessee Valley Divide )
Nora 4 SSE - Elevation 2650 feet
Average Daily MAX: 47.9 degrees
Average Daily MIN: 31.2 degrees
MEAN: 39.6 degrees
Highest Temperature: 66 degrees
Lowest Temperature: 12 degrees
Total Snowfall: 4.8"
Total Precipitation: 3.40"
2013 Precipitation: 52.20"

November 2013 was colder than average with near average precipitation, a notable and distinct miss from the above to much above average warmth predicted by "some experts" as the month dawned!

In the High Knob Massif the month produced more than 5.00" of total precip in upper elevations, 
to include 6-10" of snowfall above 3000 feet.

Thanksgiving Day At 2:38 PM
Eagle Knob of High Knob Massif
Rime & Wind Blown Snow Beneath Blue Skies
Photograph by Steve Blankenbecler - © All Rights Reserved.

While marking the 5th measurable snow of the 2013-14 season atop the High Knob Massif, this was easily the most significant.


Climate Statistics
For Autumn 2013
( September-November )

( Lower Elevations of Russell Fork Basin )
Clintwood 1 W - Elevation 1560 feet
Average Daily MAX: 63.4 degrees
Average Daily MIN: 40.3 degrees
Autumn MEAN: 51.8 degrees
Total Precipitation: 7.98"
Total Snowfall: 4.7"

( Northern Base of High Knob Massif )
City of Norton - Elevation 2141 feet
Average Daily MAX: 61.7 degrees
Average Daily MIN: 37.7 degrees
Autumn MEAN: 49.7 degrees
Total Precipitation: 8.99"
Total Snowfall: 5.5"

( Along the Tennessee Valley Divide )
Nora 4 SSE - Elevation 2650 feet
Average Daily MAX: 60.5 degrees
Average Daily MIN: 44.5 degrees
Autumn MEAN: 52.5 degrees
Total Precipitation: 9.31"
Total Snowfall: 5.1" ( M )

Autumn 2013 had below average precipitation and near to slightly below average temperatures, mostly driven by November coldness.

September 2013
Northern Hemisphere
850 MB Air Temperature Anomalies

October 2013
Northern Hemisphere
850 MB Air Temperature Anomalies

November 2013
Northern Hemisphere
850 MB Air Temperature Anomalies

Autumn 2013
September-November
850 MB Air Temperature Anomalies

The mean autumn pattern during 2013 featured above normal heights across the northern Pacific Ocean, with a strong anomaly centered over the Gulf of Alaska and along the Aleutians.

Autumn 2013
September-November
500 MB Geopotential Height Anomalies

This was reflected at the surface by 
higher pressures during Autumn 2013,

Autumn 2013
September-November
Mean Sea Level Pressure Anomalies


and especially in November 2013,

November 2013
Northern Hemisphere
Mean Sea Level Pressure Anomalies

in regions of the climatological mean 
positions of the Aleutian & Icelandic lows.

This was in general opposition to the mean standing planetary wave pattern across the Northern Hemisphere.

Low pressure over the North Pacific tends to generate Wave 1 activity, while high pressure over this same region tends to force Wave 2 ( high height anomalies over the northeastern Pacific, in particular, as exemplified by January 2009, can generate very strong Wave 2 action upward into the stratosphere ).

It is therefore no surprise to find Wave 1 
activity penetrating into the upper troposphere


and mid-upper stratosphere dropping below 
average, especially during November 2013.


Note the bold BLACK line above is the climatological mean observed during 1978-79 through 2012-13, with the BLUE line denoting conditions during 2012-13.  The record-level Wave 1 amplitude observed near the end of 2012 resulted in a
Sudden Stratospheric Warming ( SSW ) in January 2013.

Stratospheric Section - Tropospheric-Stratospheric Coupling

Due to observed anomalies, Wave 2 activity trended above average in autumn and was most anomalous during late October through mid-November in the extreme upper troposphere.



Wave 2 was above average but had a much more difficult time penetrating into the mid-upper stratosphere.

Temperatures above the North Pole have again trended below average this autumn, but not quite as extreme as during Autumn 2012.


Note that about this time last year ( late November-early December ) near record cold temperatures above the North Pole suddenly warmed as significant Wave 2 action preceded very strong Wave 1 
( see blue lines on previous wave charts ).

Eventually, last winter, this enhanced Wave activity resulted in a weakening of the Polar Vortex and complete reversal of the zonal mean westerly winds at 60 degrees north latitude and 10 MB 
( to generate a major SSW event ).


Observe by looking at these charts how the Polar Vortex gets weaker as temperatures in the stratosphere warm and wind speeds decrease toward 0, or calm, and how it becomes stronger as temps get colder and wind speeds increase.  A technical SSW ( Sudden Stratospheric Warming ) occurs when zonal mean winds reverse direction at 60 N ( drop to the negative side of 0 above ) and temperatures show a dramatic increase ( especially from
60-90 degrees north latitude as illustrated below ).




High Impact Pattern Ahead
Excessive Precipitation Potential
December 5-10 Period of 2013
( December 1978 Analog )

Although no two months or seasons are exactly alike, there are analogs in climatology that can be used as guidance to what may be upcoming at certain times.

Searching through the database of years, perhaps the best fit to this present time can be seen in 1978.

November 2013
Northern Hemisphere
30 MB Geopotential Height Composite Anomalies

At the 30 MB level of the mid-upper stratosphere only the MEAN anomaly positions for the month of November rotate around, such that if one did not see the DATES it could be believed that this was the same time period ( not 35 years apart! ).

November 1978
Northern Hemisphere
30 MB Geopotential Height Composite Anomalies

November 2013
Northern Hemisphere
500 MB Geopotential Height Composite Anomalies

The 500 MB anomalies are also analogous but somewhat more varied in placement and intensity than at 30 MB.

November 1978
Northern Hemisphere
500 MB Geopotential Height Composite Anomalies

Mean temperatures were colder in November 2013 verses 1978 in this region of the southern Appalachians, with also more snow ( as might be suggested by the above average 500 MB heights over the eastern USA in November 1978 = implied warmer conditions ).

It is striking to look at the composite 500 MB anomalies for December 1-10, 1978 in comparison with the upcoming 1-5 day forecasted composite 500 MB anomalies across the Northern Hemisphere from the ECMWF Model.

December 1-10, 1978
Northern Hemisphere
Actual 500 MB Geopotential Height Anomalies

Being 35 years apart in time, 
this is almost as close as they get!

00z Model Run December 3, 2013
ECMWF Model Composite Anomalies for DAYS 1-5
Forecasted 500 MB Geopotential Height Anomalies

While the upcoming forecast period will be riddled with subtle but important details, such as where is the rain-frozen line at any given time and place, this strong analog correlation greatly increases confidence in excessive precipitation potential for the southern Appalachians and adjacent foothills.

Climate teleconnections and this correlation overwhelmingly support the bulk of heaviest precipitation falling as rain across the southern Appalachians, with numerous different models for several days ( as of December 4 ) predicting totals in the range of 4.00" to 6.00"+ ( with cold air arriving next week ).

Although enough cold air, as later noted, may arrive to generate icing and/or frozen types for locations along and northwest of the High Knob Massif - Tennessee Valley Divide and Pine Mountain by Friday Night into Saturday Morning.

While the second main wave of precip may see frozen types at its start ( Saturday Night-Sunday AM ) and toward its end, early next week, climate teleconnections currently do not support any long-lived, bitter cold for the southern Appalachians ( like occurs across the northern-central portions of the USA ).


More Data From The Analog
of December 1978

During December 1978 a distinct northwest to southeast precipitation gradient set up across the Appalachians in a manner not unlike forecast by graphics above ( only time will tell where the heaviest axes of precip set up in coming days ).

Two distinct waves of heavy rainfall 
also characterized this 1978 event.

*Precipitation Amounts
( December 1-10, 1978 )

Huntington, WV: 6.64"

Wise 1 SE: 5.17"

John W. Flannagan Dam: 4.64"

Clintwood: 4.52"

Grundy: 4.44"

North Fork of Pound Lake: 4.26"

Pennington Gap: 4.25"

Tri-Cities, TN: 2.67"

Burkes Garden: 2.47"

Blacksburg NWSO: 2.45"

Trout Dale 3 SSE: 1.88"

Wytheville 1 S: 1.55"

*Before recording began in the City of Norton
and High Knob Massif.

The USA Storm Data publication was impressive for the foothills and Bluegrass regions during this December 1978 period.

December 7-13, 1978
Kentucky Storm Damage Reports

December 8-9, 1978
West Virginia Storm Damage Reports

Minor stream flooding was recorded in Storm Data for southwestern Virginia; however, was all data collected and properly documented ( as has been found upon review of most major winter storms impacting this area during past decades, 
the full story has not been told ).

Back to this event....


( December 4-10, 2013 )
Stagnant Upper Pattern
Early December 2013

The upper air flow pattern has been stuck in place across the USA during the past week, locking bitter conditions into central-northern portions of the nation as relative mildness supported a dominance of liquid precip across the southern Appalachians 
( with more freezing rain-moisture than snow ).

Time Series of 500 MB Pattern

Click consecutively on images for motion

December 4, 2013 at 7:00 AM
European Model 500 MB & Surface Analysis

December 4, 2013 at 7:00 PM
European Model 500 MB & Surface Analysis

December 5, 2013 at 7:00 AM
European Model 500 MB & Surface Analysis

December 5, 2013 at 7:00 PM
European Model 500 MB & Surface Analysis

December 6, 2013 at 7:00 AM
European Model 500 MB & Surface Analysis

December 6, 2013 at 7:00 PM
European Model 500 MB & Surface Analysis

December 7, 2013 at 7:00 AM
European Model 500 MB & Surface Analysis

December 7, 2013 at 7:00 PM
European Model 500 MB & Surface Analysis

December 8, 2013 at 7:00 AM
European Model 500 MB & Surface Analysis

December 8, 2013 at 7:00 PM
European Model 500 MB & Surface Analysis

December 9, 2013 at 7:00 AM
European Model 500 MB & Surface Analysis

December 9, 2013 at 7:00 PM
European Model 500 MB & Surface Analysis

December 10, 2013 at 7:00 AM
European Model 500 MB & Surface Analysis

December 10, 2013 at 7:00 PM
European Model 500 MB & Surface Analysis


Time Series of 850 MB Pattern

Click consecutively on images for motion

The temperature gradient became extreme from NW to SE of the Ohio River, which aided formation of a low-level jet and transport of deep moisture northeast along and west of the Appalachians.

12z December 4, 2013 ( 7 AM Local Time )
ECMWF 850 MB Temperature & Surface Analysis

00z December 5, 2013 ( 7 PM December 4, 2013 )
ECMWF 850 MB Temperature & Surface Analysis

12z December 5, 2013 ( 7 AM Local Time )
ECMWF 850 MB Temperature & Surface Analysis

00z December 6, 2013 ( 7 PM December 5, 2013 )
ECMWF 850 MB Temperature & Surface Analysis

12z December 6, 2013 ( 7 AM Local Time )
ECMWF 850 MB Temperature & Surface Analysis

00z December 7, 2013 ( 7 PM December 6, 2013 )
ECMWF 850 MB Temperature & Surface Analysis

12z December 7, 2013 ( 7 AM Local Time )
ECMWF 850 MB Temperature & Surface Analysis

00z December 8, 2013 ( 7 PM December 7, 2013 )
ECMWF 850 MB Temperature & Surface Analysis

12z December 8, 2013 ( 7 AM Local Time )
ECMWF 850 MB Temperature & Surface Analysis

00z December 9, 2013 ( 7 PM December 8, 2013 )
ECMWF 850 MB Temperature & Surface Analysis

12z December 9, 2013 ( 7 AM Local Time )
ECMWF 850 MB Temperature & Surface Analysis

00z December 10, 2013 ( 7 PM December 9, 2013 )
ECMWF 850 MB Temperature & Surface Analysis

12z December 10, 2013 ( 7 AM Local Time )
ECMWF 850 MB Temperature & Surface Analysis

00z December 11, 2013 ( 7 PM December 10, 2013 )
ECMWF 850 MB Temperature & Surface Analysis

The periods for frozen in the 
High Knob Massif area included:

Late December 6 into Early December 7

Late December 7 into Early December 8

Later December 9 into December 10

A sharp 20 degree temperature drop was observed in the corridor from Norton-Wise to Clintwood between Midnight and 3:00 AM December 6, with readings falling from lower 60s to lower 40s at Lonesome Pine Airport in Wise.

Another sharp temperature drop to below freezing occurred between 7 PM & 10 PM Friday Night, with significant icing ( as expected ) along and N-NW of the High Knob Massif and Tennessee Valley Divide where upsloping aided low-level cooling and precipitation production.


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