Mountain Area Forecast ( Feb 13-15 )

An ALERT For Heavy, Wet Snow Is In Effect From  10:00 PM Tuesday Until 10:00 AM Wednesday For Elevations Above 2500-3000 Feet

Rain and wet snow, with mostly snow above 3000 feet in elevation, is expected to develop across the area late Tuesday Night into Wednesday.  Significant amounts of snow will be possible for upper elevations, above 3000 feet, with light-moderate snowfall amounts at elevations above 2500 feet.

Little to no snow accumulation is expected below 2000 feet.

NW winds will continue to gust 30-40+ mph at mid-upper elevations overnight into early Monday, especially on the mountain ridges, with dropping wind chill values as air temperatures continue dropping.  Caution is advised.

Overnight Into Monday Morning

Partly cloudy.  Windy.  NW winds 10-20 mph, with higher gusts, especially on mid-upper elevation mountain ridges and plateaus.  Temperatures dropping into the 20s, varying from near 20 degrees highest elevations to near 30 degrees. Wind chills in the 10s and 20s, except single digits in gusts along upper elevation mountain ridges.

Monday Afternoon

Mostly sunny.  Some increasing high clouds by mid-late afternoon.  NW winds diminishing to 5-10 mph, with a few higher gusts along mountain ridges.  Temperatures varying from low-mid 30s in upper elevations to the low-mid 40s.

Monday Night Into Tuesday Morning

Increasing mid-high altitude clouds.  Light winds shifting WSW to WNW at 5-10 mph, with higher gusts, along upper elevation mountain ridges.  A vertical temp spread from 10s to middle 20s in mountain valleys versus 30s along exposed middle to upper elevation mountain ridges-plateaus.

Tuesday Afternoon

Partly to mostly cloudy.  SW winds increasing to 5-15 mph, with some higher gusts.  Temperatures varying from 30s in upper elevations to the mid 40s to around 50 degrees at the lower-middle elevations.  Wind chills in the 20s and 30s on gusty mid-upper elevation mountain ridges.

Tuesday Night Into Mid-Morning Wednesday

Rain, sleet & snow developing.  Heavy, wet snow possible, especially at elevations above 2500-3000 feet.  SW winds shifting W-NW at 5-15 mph, with higher gusts.  Temps from the 20s in upper elevations to the low-mid 30s.

Snowfall Forecast: 10 PM Tuesday – 10 AM Wednesday

A general 3″ to 5″ of snow is expected above 3000 feet in the High Knob Massif to Black Mountain corridor, with locally higher amounts to around 6″ possible in the massif ( this also includes upper elevations of Clinch Mountain and the Whitetop-Mount Rogers area in southwestern Virginia ).

Target Snowfall of 2″ In Wise (+/-) 1″ Error Potential.  This suggests the potential for 1″ to 3″ of snow at elevations below 3000 feet in the middle elevation zone.  Little to no snow is now expected to accumulate at elevations below 2000 ( within lower elevations ).

A general 1″ to 2″ is expected above 2200 feet, with rain & snow and little to no accumulation expected at elevations below 2000 feet.

*While nearly all snow is expected above 3000 feet elevation, the ultimate amounts observed across middle elevations will be determined by how low the level of sticking snow drops overnight into Wednesday morning.

Weather Discussion ( To Snow Or Not )

Tuesday Afternoon Update

An elevation biased snow event will be developing Tuesday Night into Wednesday Morning.  Significant differences in amounts are expected in the vertical, varying from little to no accumulation below 2000 feet to as much as 3″-6″ above 3000 feet in the High Knob Massif-Black Mountain area.

A mackerel sky above UVA-Wise is a sign of changing weather conditions upcoming tonight into Wednesday Morning.

Wet, slushy snow amounts of 1-2″ will be possible down to around the elevations of Norton-Wise, and adjacent ridge communities across central-southern Wise and Dickenson counties ( mainly during the overnight-predawn period ).

Hazardous travel conditions are expected in locations that are impacted by a fall of wet snow ( snow to water ratios are expected to be around 10:1 during this event ).

Early afternoon temperatures in the upper 30s ( 38 degrees on Black Mountain, hovering in the 36 to 37 degree range on Eagle Knob of the High Knob Massif ) and dewpoints in the 10s indicates significant evaporative cooloing will produce all snow at highest elevations, with a mixture of rain-snow and sleet possible during this fast hitting event at lower and middle elevations.

Previous Discussion

Sunday ( February 12 ) featured the warmest temperatures since mid-November, followed by a strong downward turn that will continue into this Monday morning.

Reference my 021017 Forecast Discussion to review ROARing winds that should have produced a High Wind Warning ( the Morristown NWSFO did issue a Wind Advisory ).

The main focus now shifts to a mid-week system that has now been “outlooked” for a long time by models.  While a major winter storm has never been expected for the area, this system can not be written off as a non-accumulation event with potential of significant snow remaining for February 15 ( especially above 2000-3000 feet ).

Part of the energy with this southern energy will hold back over Mexico, as the remainder passes across the Mountain Empire to form another phasing event ( the 3rd in a series ) with northern stream energy over New England.  Bombogenesis looks to again occur with an intense surface low lifting toward Nova Scotia.

An east-based -NAO ( negative North Atlantic Oscillation ) is currently in place but will feature propagating 500 MB heights into Europe from Greenland ( i.e., a transitory or moving block featuring anomalously high 500 MB heights ) as this next storm develops and bombs near Newfoundland-Nova Scotia.

With the event just now coming into view of high resolution models, new runs through Monday into Tuesday will need to be closely followed.  Currently ( as of 1:30 AM Monday ) the NAM 4 KM, GFS Model and the European Model are all in rather close agreement on several inches or more of snow accumulation at higher elevations in southwest Virginia.

The 00z Monday ( 7 PM Sunday ) run of the European 9 KM Model is forecasting 2″ to 5″ of snow across higher elevations in southwest Virginia.  The new European still has trouble fully resolving local terrain, so snow amounts and levels are not set.  These are only preliminary numbers that will likely change in the next 24 hours.

I will update again by late Monday Night-early Tuesday.

The Bottom Line…A southern stream system passing across the Mountain Empire into Wednesday ( Feb 15 ) will bring the potential of accumulating snow.

It remains too early yet to tell about snow amounts; although, the preliminary view suggests that heaviest snowfall totals will likely occur at elevations around and above 2000 to 2500 feet.  Several inches or more is an initial guess by models.  Stay tuned for updates.

The UP and DOWN pattern of this winter season will roll onward, with another significant warm period expected by this weekend into next week…followed, it appears, by yet another big downward turn and more winter precipitation potential by the middle or end of next week ( i.e., during final days of February 2017 ).

Mountain Area Forecast ( Feb 10-12 )

ALERT For Strong SW Winds From Late Friday Afternoon Into Saturday For The Cumberland Mountains ( Wind Gusts 30-50+ MPH )

Strong SW winds will develop Friday PM into Friday Night, with ROARING speeds at middle-upper elevations as strong warm air transport occurs.  Strong winds, with mountain waves, are also likely in lower elevations of the Pound to Clintwood corridor.  

Although 30 to 50 mph gusts are expected, local wind gusts could top 60 mph at highest elevations in the High Knob Massif.  Windy conditions will continue through this weekend at high elevations.

Overnight Into Friday Morning

Partly cloudy ( high altitude ice crystal clouds ).  Light and variable winds generally less than 10 mph along mid-upper elevation mountain ridges.  Temperatures widespread in the 10s, with single digits in colder mountain valleys of middle-upper elevations.

Friday Afternoon

Becoming partly-mostly sunny & windy.  SSW-SW winds increasing to 10-20 mph, with higher gusts, on mountain ridges & plateaus below 2700 feet.  SW winds 15-25 mph, with higher gusts, on mountain ridges above 2700 feet.  Temperatures in the 30s to low-mid 40s.  Wind chill factors in the 20s and 30s, except 10s in gusts at highest elevations.

Friday Night Into Mid-Morning Saturday

Partly to mostly clear.  Increasing clouds toward morning with a chance of rain showers.  Windy.  SSW-SW winds 25-35 mph, with higher gusts of 40 to 50+ mph.  Temperatures mostly in the 30s and 40s ( steady or slowly rising at high elevations and locally colder in valleys with calm winds ).  Wind chills in the 20s & 30s ( coldest high elevations ).

Saturday Afternoon

Cloudy.  A chance of rain showers.  Gusty.  SW winds 5-15 mph, with higher gusts, along mountain ridges-plateaus below 2700 feet.  SW-WSW winds 15-25 mph, with higher gusts, on mountain ridges above 2700 feet.  Temps in the 40s to around 50 degrees.  Dense fog developing within upper elevations.

Saturday Night Into Sunday Morning

Low clouds and showers.  Areas of dense fog, widespread amid upper elevations.  SW winds 10-20 mph, with higher gusts, along mountain ridges-plateaus below 2700 feet.  Winds WSW-SW at 15-25 mph, with higher gusts, along mountain ridges above 2700 feet.  Temperatures steady or rising into the 50s in most locations ( upper 40s to around 50 degrees within cooler places ).

The potential for a winter storm with a Great Lake connection into the southern Appalachians is being monitored for the February 15-16 period.  Stay tuned for later updates.

Weather Discussion ( Windy )

My late evening update is to increase sustained wind speeds which are topping 30 mph in Wise and on mountain ridges, with occasional strong gusts into lower elevations around Pound and Clintwood.

It takes a stout tripod to shoot tonight!

Previous Discussion

The up and down pattern rolls forward with the latest plunge featuring a general 1″ to 3″ of snow across upper elevations in the High Knob Massif.  It was literally a transition from thunderstorms to snow in short order.

Snow occurred without any direct and sustained connection to the Great Lakes, as surface to 850 MB flow trajectories missed the area toward the northeast.  Next week, if the European Model group is accurate, another storm will produce a Great Lake connection that finally reaches the southern Appalachians.  IF that actually occurs then snow amounts will be more significant even though current models do not yet recognize it ( very limited Great Lake moisture has so far been observed in this 2016-17 snow drought season ).

At this time of year a set up like next week might feature a huge winter storm, if northern and southern jet stream waves were to phase; however, at this time, models are keeping those separated until energy reaches the Atlantic Coast where formation of another important Nor’easter occurs.

Most of the surrounding area reported 1″ or less of snow.

Preliminary Snowfall Reports

UVA-Wise: 0.3″

Clintwood 1 W: 0.4″

Nora 4 SSE: 0.9″

City of Norton Water Plant: 1.3″
( 1″ ground )

High Chapparal of High Knob Massif: 2.0″
( 2″ ground )

Eagle Knob of High Knob Massif: 2.7″
( 1″ to 4″+ ground )

While it is common for orographic clouds to cap upper elevations amid the High Knob Massif, they also develop & dissipate at times as the crests and troughs of their wave form “flow” or translate across the massif.  I experienced this during the afternoon hours of February 8, well ahead of showers-thunderstorms, with a gush of strong wind carrying dense fog ( clouds ) across the sprawling crest to reduce visibility to mere feet for a while before the wave trough, with subsiding air, would arrive to dissipate the low-level orographic cloud.  Then, after a period of time, the next wave of clouds would build and overspread the high country.

It is possible that this was connected to a higher level wave train; although, without profiler data it was not possible to be certain.  I did observe many waves above the low-level orographic clouds, to include stacked lenticular forms at times.

Watching the clouds blowing into and across the crest zone in swirling sheets, it was easy to envision how the snow would soon do the same into February 9.  And it did!

Snow was minor compared to the HUGE temperature change that occurred as part of this ongoing pattern dominated by UP and DOWN swings.

If considering wind chills, of course, the actual feels-like conditions were even more impressive than these charts   indicated between February 8 and February 9.

This has been an atypical winter season.  Temperatures tonight have dropped into single digits in high valleys of the High Knob Massif, as they did during February 4, yet conditions are still not prime for ultimate MINS with high clouds developing during a very progressive ( restless ) weather pattern.

Now the focus turns to WIND and plenty of it from Friday through this weekend, with strong winds dominating this period across the mountains.  Initially this wind will keep conditions feeling cold, but eventually milder air wins out yet again as rain showers, low clouds, and areas of dense fog develop this weekend.

Mountain Area Forecast ( Feb 6-9 )

Current ALERT For Accumulating Snow & Hazardous Driving Conditions In Combination With Bitter Cold Air Is In Effect Into Mid-Day Thursday For Locations Along The Upslope Side Of The Cumberlands ( With Respect To NW Winds )

Snow-ice accumulations are expected in most locations along the upslope side of the mountains ( down to 1000-1500 feet ) through mid-morning Thursday.  Accumulations of 1″ or less are generally expected below 2500 feet, with 1″ to 2″ expected above 3000 feet.  Locally higher amounts will be possible within upper elevations  of the High Knob Massif, Black Mountain and Clinch Mountain.

*As of 5:30 to 6:00 AM a combination of sleet & snow was falling in lower elevations from Pound to Clintwood ( 30 degrees at 1560 feet elevation in Clintwood ) with sticking occurring.  Generally all snow was falling at mid-upper elevations with portions of State Route 619, Route 237 and Route 238 icy and snow covered in upper elevations of the High Knob Massif where the air temperature had fallen to around 20 degrees.  In between, many roads in middle elevations are developing slick patches.  

The Storm Prediction Center Has Issued A Marginal To Slight Risk For Severe Thunderstorms For Wednesday Afternoon & Evening

ALERT For Development Of Strong SW Winds From Monday Night Through Tuesday At Middle-Upper Elevations In The Cumberland Mountains

Periods of showers, with a chance for thunderstorms, will be possible from late Monday through Wednesday.  Strong & gusty SW winds will transport abundant moisture into the mountains with a heavy rainfall potential as a boundary slows.  Much colder air with a wind shift to the WNW-NNW is expected by Thursday.

Cold air and upslope snow accumulations are being monitored for Thursday.  Stay tuned for later updates on this wintry potential.

Overnight Into Monday Morning

High clouds.  Seasonally cold.  Winds SW at 5-10 mph, with some higher gusts, along mid-upper elevation mountain ridges.  Large vertical temperature spread between colder valleys and milder ridges.  Temperatures varying from the 10s to middle 20s in colder valleys to the low-middle 30s.

Monday Afternoon

Becoming cloudy with a chance of showers, especially by late.  SSW winds increasing to 5-15 mph, with higher gusts, below 2700 feet.  SW winds 10-20 mph & gusty on mountain ridges above 2700 feet.  Temperatures varying from upper 40s-lower 50s at highest elevations to the mid to upper 50s to around 60 degrees ( warmest in downslope locations from Pound-Clintwood to Haysi-Grundy ).

Monday Night Into Tuesday Morning

A chance of showers.  Windy.  SSW-SW winds 10-25 mph, with higher gusts, on mountain ridges & plateaus below 2700 feet.  SW winds 20-35 mph, with higher gusts, along mountain ridges above 2700 feet.  Temperatures mainly in the 40s to around 50 degrees.  Areas of dense fog ( generally widespread in upslope areas of the High Knob Massif ).

Tuesday Afternoon

Cloudy & windy.  A chance of showers & thunderstorms.  SSW to SW winds 15-25 mph, with higher gusts.  Mild with temperatures varying from low-mid 50s highest elevations to the low-mid 60s.

Strong rises on creeks & streams will be possible if heavy rainfall develops into Wednesday.  People living and driving through flood prone, low-lying locations will need to remain alert to changing weather conditions.

Tuesday Night Into Mid-Morning Wednesday

Showers with a chance for thunderstorms.  Locally heavy rainfall.  SSW-WSW winds 10-20 mph, with higher gusts, along middle to upper elevation mountain ridges.  Temps in the 40s to lower 50s.  Areas of dense fog ( widespread amid upper elevations ).

Wednesday Afternoon-Early Evening

Showers with a chance for thunderstorms by late.  Locally heavy rainfall amounts.  Some storms could be strong to locally severe.  SW winds shifting NW at 10-20 mph, with higher gusts.  Temperatures varying from lower 50s at highest elevations to the lower-middle 60s.

A temperature plunge is expected into Thursday with snow accumulations.  Amounts of 1″ or less are expected below 3000 feet, with 1-2″ above 3000 feet.  Locally higher amounts will be possible at highest elevations in the High Knob Massif.

Weather Discussion ( Stormy )

A stormy weather pattern is taking shape as air masses clash across the region during coming days, with large temperature fluctuations expected this week.

Low pressure developing in the lee of the Rockies will track east toward the Great Lakes and into northeastern Canada by Wednesday, with a trailing front and additional waves continuing rainfall along the mountains.

Climatology of forecast wind vectors suggests that a heavy rainfall potential will arise along the western slopes of the Appalachians, with some models like the NAM beginning to reflect this in their forecast’s.  These need to be monitored closely today into Tuesday.

Meanwhile, the Storm Prediction Center ( SPC ) has issued a marginal to slight risk of severe thunderstorms for a large region along and mainly west of the Appalachians for the Tuesday-Wednesday period.

Although a wild up and down pattern continues, the MEAN of the 51-Member European Ensemble group suggests that winter is by no means over.

The potential for an important winter storm impacting the eastern USA remains alive, despite a notable ( record pace ) snow drought across the southern Appalachians.

Reference Late Winter In The High Knob Massif for a brief look at some snow lingering amid the high country from January 29-30.

Mountain Area Forecast ( Feb 3-5 )

Strong SW Winds And Some Light Snow & Mix Will Be Possible Into Superbowl Sunday Morning – Especially Along And Southwest Of The High Knob Massif And Tennessee Valley Divide

A seasonally cold air mass across the Cumberland Mountains will continue through this weekend.  Strong winds will develop at the middle-upper elevations Saturday Night into Sunday as a limited moisture containing disturbance crosses the mountains.

Overnight Into Mid-Morning Friday

Mostly cloudy.  Small chance of some flurries.  Light northerly winds generally less than 10 mph.  Temps widespread in the 20s ( varying from upper 10s in the coldest locations to the upper 20s ).  Milder southward within the Great Valley.

Friday Afternoon

Partly to mostly cloudy.  NW winds 5-15 mph, with some higher gusts.  Temperatures varying from low-mid 20s at highest elevations to the mid-upper 30s.  Wind chills in the 10s and 20s to around 30 degrees.

Friday Night Into Mid-Morning Saturday

Mostly clear.  Cold.  Northerly winds decreasing to generally less than 10 mph on mid-upper elevation mountain ridges.  Temperatures varying from single digits in colder valleys of upper elevations within the High Knob Massif to the middle-upper 10s.

Saturday Afternoon

Mostly sunny.  Cold.  Light northerly winds shifting SE to S and increasing to 5-15 mph, with higher gusts, on middle-upper elevation mountain ridges by late.  Temps varying from upper 20s to lower 30s in upper elevations to the upper 30s to lower 40s.

Saturday Night Into Sunday Morning

Becoming cloudy and windy.  Chance of light snow and mix developing during the predawn-morning.  S-SSW winds 5-15 mph, with higher gusts, on mountain ridges-plateaus below 2700 feet.  SW-WSW winds 15-25 mph, with higher gusts, on mountain ridges above 2700 feet.  Temps widespread in the 20s to near 30 degrees.  Wind chills in the 10s and 20s.

Superbowl Sunday Afternoon

Mostly cloudy. Small chance for a shower-flurry.  Freezing fog possible along high crestlines in the High Knob Massif.  Winds SW to W at 5-15 mph, with higher gusts along upper elevation mountain ridges.  Temperatures mainly in the 30s to low-mid 40 degrees ( near 30 degrees highest elevations ).  Wind chills in the 20s to lower 30s, except 10s along the highest mountain ridges.

A major storm system is being monitored for the February 7-9 period.  Strong winds, thunderstorms and significant rainfall amounts will be possible prior to a temperature plunge.  Stay tuned for later updates.

Weather Discussion ( Chilly )

A seasonally chilly air mass will continue to dominate the Cumberland Mountains through this weekend.  Snow cover remains widespread at upper elevations in the High Knob Massif ( especially northern slopes ) where slick conditions continue to be observed in patches on northern slope roads.

*Visitors to the High Knob Lookout should use caution, especially along the northern face of the mountain on Route 238 as well as on portions of State Route 619 & Route 237 ( toward Big Cherry Lake ). 

Reference my 013017 Forecast Discussion for details on the snow.

The 6-8″+ of snow did not disappear overnight in the high country of the massif, especially within the lofty basins and northern slopes of upper elevations.

Although this weekend system will have limited moisture, strong winds will offer at least the opportunity for some orographic enhancement to occur into Sunday morning as strong SW winds blow upward into the high country of the massif and adjacent Tennessee Valley Divide.  Just a little more moisture than currently predicted by models would make it notable, so stay tuned for possible updates if you live from the Wise & Sandy Ridge plateaus southwest.

The main focus through this next week will be on a major storm system, with powerful low pressure development, which will push the 0 Celsius ( 32 F ) line far to the north Tuesday ( above ) before temps crash by Thursday ( below ).

Stay tuned for later updates on this potent storm system.

Mountain Area Forecast ( Jan 30-Feb 2 )

No Alerts Currently In Effect

Former Alert

ALERT For Strong SW Winds Developing Late Tonight Into Tuesday With 30 to 50+ MPH Gusts Along Middle To Upper Elevation Mountain Ridges-Plateaus ( the highest wind gusts generally in upper elevations ).

A strengthening pressure gradient will develop overnight into Tuesday morning as another clipper system passes across the Great Lakes.  Blowing snow could be a factor for high elevation routes such as State Route 619, 238, 237, 160 as well as others, passing through upper elevations of the High Knob Massif and across the Virginia-Kentucky border on Black Mountain.  The strongest low-level jet of roaring wind is expected to pass, with speeds diminishing somewhat, after 10:00 AM to Noon Tuesday.  Gusty conditions will continue through Tuesday Night at high elevations.  Caution is advised.

Overnight Into Tuesday Morning

Partly cloudy.  Becoming windy.  SW winds increasing to 15-25 mph, with higher gusts, along mountain ridges-plateaus below 2700 feet.  SW winds 20-30 mph, with higher gusts, along mountain ridges above 2700 feet.  Blowing snow at high elevations in the High Knob Massif.  Temperatures in the 20s to around 30 degrees, tending to rise into morning.  Wind chills in the single digits & 10s, rising into the 10s and 20s toward morning.

Tuesday Afternoon

Partly-mostly cloudy ( mid-high clouds ).  Windy.  SW-WSW winds 10-25 mph, with higher gusts.  Temperatures varying from upper 30s to lower 40s at highest elevations to lower-middle 50s ( warmest in downslope locations from Pound to Clintwood and Haysi-Grundy ).  Wind chills in the 20s and 30s ( coldest at highest elevations ).

Tuesday Night Into Wednesday Morning

 Partly to mostly cloudy.  W-NW winds 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges.  Temperatures varying from upper 10s to lower 20s in the coldest valleys to the middle-upper 30s.  Wind chills in the 20s and 30s along exposed mid-upper elevation ridges.

Wednesday Afternoon-Early Evening

Partly to mostly cloudy.  Variable winds generally less than 10 mph.  Small chance of a rain shower or a high elevation snow shower by the late afternoon or early evening.  Temps varying from upper 30s to lower 40s in upper elevations to the upper 40s to lower 50s.

Wednesday Night Into Thursday Morning

Partly-mostly cloudy.  Winds NW-N at 5-10 mph, with higher gusts, along middle-upper elevation mountain ridges.  Temperatures varying from low-mid 20s to the lower-middle 30s.  Wind chills dropping into the 10s on upper elevation ridges overnight into morning.

A progressively colder pattern Thursday into this weekend, with temperatures near to somewhat below average for this time of year, is being monitored ahead of a developing wave in the flow field.  A chance of frozen precipitation types will become possible by late Saturday into Superbowl Sunday.  Stay tuned for later updates.

Development of a major storm system is currently being outlooked for the February 7-9 period.  Strong winds and a significant temp spike & plunge will be possible with this storm system, along with moderate-heavy precipitation.  Stay tuned for later changes.

Weather Discussion ( Windy )

A majestic sunset in wake of the snow will now give way to increasing wind into Tuesday.  As so often is the case at this time of year, this will take the edge off warming at middle to upper elevations, especially, and across all locations in the Cumberland Mountains where winds are strong.

Although temperatures climb some Tuesday-Wednesday, they will drop back Thursday into this weekend to produce a seasonally chilly pattern through the next week.  A couple of potentially important systems are upcoming during the next 5-10 days, but details remain to be worked out.

Preliminary Snowfall Report
( January 29-30 System )

UVA-Wise NWS: 1.6″
( 2″ ground )

The Pines In Dungannon: 2.7″
( 2″ ground )

Clintwood 1 W: 2.8″
( 0.16″ NWS Rain Gauge )

Nora 4 SSE: 3.2″
( 0.19″ NWS Rain Gauge )

City of Norton WP: 4.0″
( 0.28″ NWS Rain Gauge / 3.0-3.5″ ground )

Head of Powell Valley: 4.5″
( 4″ ground )

High Chaparral of High Knob Massif: 6.5″
( 6″ ground )

Eagle Knob of High Knob Massif: 8.5″
( variable wind blown depths )

*Totals ideally include that which stuck-melted and/or settled during the event; although, all totals may not fully reflect this aspect which naturally creates variability in ground depths.  The addition of strong winds, like experienced at high elevations in the High Knob Massif, being a major factor in depth variations. 

Conditions were simply wicked within upper elevations of the High Knob Massif with prolonged, persistently heavy snow during the overnight period.

*Air temperatures in the low-mid 10s combined with wind gusts of 30+ mph to generate below zero wind chills, with snow & blowing snow causing low visibility and large snow depth variations.

While upslope snowfall was key, a snowstreak that was long-lived extended from Black Mountain to the Head of Powell Valley and across the main crest zone of the High Knob Massif ( 6″ to 12″+ of ground depth was common by Monday morning from High Chaparral to the peak area of High Knob, varying from near bare ground in places to a couple feet or more in wind blown drifts ).

Joe & Darlene Fields have been measuring winter snowfall in the High Chaparral community of the High Knob Massif for more than 24 years ( elevation 3300 feet above mean sea level ).

Sharon Daniels verified that with around 4″ of snow at her lovely home sitting around 1850 feet above sea level in the Head of Powell Valley ( nearly 2400 vertical feet lower in elevation than the top of the massif ).

*The 8.5″ snowfall total for Eagle Knob is a best estimate, with the heaviest snow amounts across the head of Big Cherry Lake Basin which includes the peak of High Knob.

While snow cover was widespread ( solid ) in nature from the High Knob Massif-Tennessee Valley Divide ( the white line I have on the above NASA Visible Image ) northwest to north, amounts varied with embedded squalls and streaks of snow squalls ( snowstreaks ) from 1-2″ on the low end upwards to 6-8″+ on the high end.

To the south and southeast of the solid white line, or the Tennessee Valley Divide & High Knob Massif, the snow was patchy in nature and dominated by bursts of snow in the squalls supported by very cold air aloft.  Here totals varied from a dusting to 1-2″ at most as this area lacked upslope and had to rely on atmospheric dynamics.

Looking at this from a larger-scale perspective, streaks of snow can be seen across Kentucky to the northwest of the mountains amid otherwise bare ground, as once again with a lack of orographic lift snow accumulations were yet again relegated mostly to atmospheric dynamics ( cold air aloft & DPVA or Differential Positive Vorticity Advection which supported rising air and local streaks of snow ).

*Many lingering clouds prevented this from being an ideal view, but a couple solid bands of snow cover can be seen along the two fronts of the Appalachians…the Cumberland-Allegheny toward the northwest and the Blue Ridge toward the southeast.  Initial lifting and convergence of air along the Cumberland-Allegheny ranges often making up for their lower elevation versus the Blue Ridge which both MODELS and most FORECASTERS neglect.

Mountain Area Forecast ( Jan 29-31 )

ALERT For The Development Of Accumulating Snow And Hazardous Travel Conditions During Sunday Into Monday Morning ( January 29-30 )

Monday AM Update At 2:45 AM – Another area of heavy snow is beginning to move into Wise County from the west and will overspread the Norton-Wise and U.S. 23 corridor through 3:00 to 3:30 AM.  Blowing snow will add to the reduction in visibility which is expected to be near zero at times.  Another band of snow will be moving into portions of northern Dickenson and Buchanan counties.

*A persistent streak of snow has dropped significant amounts from Black Mountain into portions of the High Knob Massif since Midnight.  Expect difficult travel conditions in upper elevations, with travel not recommended.  Drifting snow is occurring.

A region of very cold air aloft will trigger flurries, snow showers and bursts of heavy snow in squalls and streaks of heavy snowfall during Sunday into Monday morning.  While the greatest amounts of snow are generally expected along the windward ( SW to NW )  sides of the Cumberland and Blue Ridge mountain ranges, locally heavy snow may also occur in portions of the Clinch, Powell, and Holston valleys.  The worst driving conditions are anticipated from late Sunday afternoon into early Monday with widespread hazardous travel developing along the usplope side of the mountains ( where SW to NW air flow rises ).

Expect rapidly changing weather and low visibility, with near whiteout conditions, in the more intense squalls and streaks of snow during Sunday PM into Sunday Night.  Caution is advised.

**An ALERT For ROARING SW Winds Will Likely Be Needed For Monday Night Into Tuesday.

Overnight Into Sunday Morning

Periods of flurries & snow showers.  Little accumulation.  Winds SW-WNW at 5-15 mph, with higher gusts.  Temps dropping into the 20s to lower 30s.  Wind chills in the 10s and 20s ( coldest on upper elevation mountain ridges ).

The best coverage of snow showers and heavier squalls is expected to generally be along and southwest of the High Knob Massif and Tennessee Valley Divide during much of Sunday, from the Wise & Sandy Ridge plateaus southwest along the Virginia-Kentucky  stateline on SSW-WSW flow.  Coverage of activity is expected to increase as instability increases into mid-day to early afternoon.

Downsloping and somewhat milder temps is expected to produce less snow accumulation toward Pound, Clintwood, and in adjacent communities across northern Wise and much of Dickenson County prior to a late afternoon wind shift.   

Sunday Afternoon

Snow showers, flurries and snow squalls-streaks of heavy snow.  Heaviest snow amounts along and southwest of the Tennessee Valley Divide and High Knob Massif.  Winds SSW-WSW at 5-15 mph, with higher gusts, shifting W-WNW late.  Temperatures in the 20s to low-mid 30s.  Wind chills in the 10s and 20s.

A wind shift to W-WNW by late Sunday afternoon into Sunday evening is expected to change the focus for heavier snowfall amounts toward locations along and west to northwest of the  High Knob Massif & Tennessee Valley Divide on W-WNW flow.

Due to very cold air aloft, any location will be at risk for a burst of heavy snow; although, best coverage is expected where air flow is forced to rise on SW to NW trajectories. 

Sunday Night Into Monday Morning

Snow showers, flurries, and snow squalls-streaks of heavy snow taping to flurries and localized snow showers toward morning.  Winds W to NW at 10-20 mph, with higher gusts.  Temperatures varying from around 10 degrees at highest elevations to the upper 10s to lower 20s.  Wind chills in the single digits and 10s, except below zero in upper elevations.

Snowfall Forecast – Sunday Into Monday Morning

A general 2″ to 6″ is expected, with a target snowfall of 4″ in the Norton-Wise area ( +/- 2″ error potential ).  Locally higher amounts will be possible at upper elevations in the High Knob Massif.  Snow depths are expected to be less than total snowfall at lower-middle elevations, where some melting will occur during Sunday.  Snow to water ratios are expected to be greater than 10:1 ( snow density low ), especially by later Sunday into Sunday Night due to bitterly cold air aloft and a relatively deep dendritic crystal growth zone within the vertical ( i.e., moisture intersecting bitter cold air ). 

Monday Afternoon

Partly cloudy.  Cold.  WNW-WSW winds 5-10 mph, with higher gusts.  Temperatures varying from the mid-upper 10s to the mid-upper 20s to lower 30s ( coldest in upper elevations ).

Monday Night Into Tuesday Morning

Variable clouds.  Becoming windy, especially at middle to upper elevations.  Temps in the 10s and 20s, then rising into the overnight-morning ( especially on mid-upper elevation mountain ridges ).  SSW-WSW winds increasing to 15-25+ mph, with higher gusts.  Wind chill values in the single digits and 10s, then rising values into morning.

Weather Discussion ( Bursts Of Snow )

Widespread snow will be impacting the mountain area on Sunday into early hours of Monday, with worst conditions developing by later Sunday into Sunday Night.

Abundant moisture and rising air during Sunday PM into Sunday Night will combine with cold air aloft to produce widespread snow and bursts of heavy snow.

There is no doubt that snow will be widespread, but amounts will vary significantly due to a combination of factors between the surface and middle troposphere ( i.e., 700-500 MB layer ).

While I expect the worst conditions to develop around and after a wind shift occurs between 1:00 PM and 7:00 PM on Sunday, there will likely be notable differences in weather conditions prior to that time with SSW-WSW flow favoring the heavier snowfall and accumulations to occur in locales where this air flow rises ( from the Sandy Ridge and Wise plateaus southwest to Norton, Powell Valley-Big Stone Gap into portions of Lee County ) versus where it sinks ( from Pound-Clintwood toward Haysi and Grundy ).

*This will be partly due to the cooling that occurs with rising air that will help keep surface temperatures lower within the lifting zone versus where this air flow sinks.  The strongest cooling and best accumulations, of course, being most favored across upper elevations in the High Knob Massif and the Black mountains.

Forecast soundings show a deep saturated layer with a steep temperature decline late Sunday into Sunday Night to support development of widespread snow, abundant bursts of snow and hazardous driving conditions.  So regardless of what happens prior to sunset on Sunday, I expect upslope locations ( with respect to W-WNW air flow ) to have the worst conditions form during this time.

*This is a classic sounding profile that past climatology shows tends to be very productive.  The main missing ingredient to keep this going and enhance it further is a lack of deep connection to the Great Lakes ( a notable missing ingredient so far during the 2016-17 Winter Season across the southern Appalachians…if this was present I would be going significantly higher on my forecast snowfall numbers ).

The Bottom Line

Widespread snow is expected Sunday into Monday AM, with an initial focus of most numerous snow showers, squalls and snowstreaks being biased toward locales where SSW-WSW air flow rises ( e.g., Wise southwest toward Big Stone Gap ) prior to a wind shift timed to occur by late afternoon Sunday.

A wind shift toward W-WNW will tend to shift the focus for most widespread snow showers, squalls and snowstreaks to locations along and west to northwest of the High Knob Massif and Tennessee Valley Divide during Sunday Night into early hours of Monday.

*Max accumulations during this event occurring where these two zones overlap, ideally, across the High Knob Massif and along the Tennessee Valley Divide.  Cold air aloft ( as noted below ) could locally skew this and allow for significant amounts in places outside of this orographic overlap zone via bursts of snow.

Due to very cold air aloft, and relatively deep moisture intersecting a zone prime for dendritic crystal growth, I expect bursts of intense snow to generate whiteout type of conditions ( i.e., low visibility ) at times.  This puts any location at risk for a burst or bursts of snow.

The worst travel conditions are expected to develop on a widespread basis by late Sunday into Sunday night.

I expect widespread school closings and delays for counties within the mountains on Monday. 

Mountain Area Forecast ( Jan 25-28 )

A Much Colder Weather Pattern Will Dominate The Mountain Region During The January 26-30 Period.  Several Waves Will Bring Flurries & Snow Showers, With The Most Significant Potential Developing By This Weekend ( January 29 ).

*Although some slick travel could develop into morning hours of Friday & Saturday, the most significant and widespread impact is expected during January 29-30 when an Alert For Widespread Hazardous Travel will be likely with moderate-heavy snow.

Overnight Into Wednesday Morning

Mostly clear.  Colder.  Areas of valley fog in low elevations.  Increasing SSW-WSW winds on mid-upper elevation ridges to 10-20 mph, with higher gusts, by morning.  Temps from the 20s to lower 30s, rising on exposed mountain ridges and plateaus during the overnight-morning.

Wednesday Afternoon

Partly to mostly sunny, then increasing clouds by late.  Windy.  SSW-SW winds 15 to 25 mph, with higher gusts.  Temperatures varying from upper 40s to low 50s in upper elevations to the upper 50s to low-mid 60s  ( warmest in downslope locations from Pound to Grundy ).

Wednesday Night Into Mid-Morning Thursday

Cloudy with evening rain developing.  Windy.  Brief downpours giving way to overnight showers and drizzle to possible flurries.  SW winds shifting W-WNW at 10-25 mph, with higher gusts.  Turning colder.  Temps dropping into the middle 20s to mid-upper 30s by morning ( coldest at the highest elevations ).  Wind chills falling into the 10s & 20s.

Thursday Afternoon

Mostly cloudy.  Cold.  Chance of flurries.  Windy.  WSW-WNW winds 10-20 mph, with higher gusts.  Temperatures nearly steady or slowly falling in the 30s ( lower-middle elevations ) and 20s ( upper elevations ).  Wind chills in the 10s & 20s ( except single digits in gusts at high elevations ).

Thursday Night Into Mid-Morning Friday

Cloudy.  Cold.  Chance of flurries & snow showers.  Light accumulations possible.  Winds W-WNW 5-15 mph, with higher gusts.  Temperatures varying from the mid-upper 10s to the mid-upper 20s to around 30 degrees ( coldest at highest elevations ).  Wind chill factors in the 10s and 20s, except 0 to 10 degrees on upper elevation mountain ridges.  Rime formation at highest elevations.

Although some light accumulations, with a dusting to locally 1″+ could occur through Saturday, the heaviest and most widespread snowfall is expected to develop during the January 29-30 period.

Friday Afternoon

Mostly cloudy.  Cold.  A chance of flurries or snow showers.  Winds W-WNW 5-15 mph with higher gusts.  Temperatures varying from upper 10s to lower 20s at highest elevations to the upper 20s to lower 30s.  Winds chills mostly in the 10s & 20s, with single digits along upper elevation ridges.

Friday Night Into Saturday Morning

Cloudy.  Snow showers.  Cold.  Light accumulations.  Winds SW-W 10-20 mph, with higher gusts.  Temperatures varying from mid-upper 10s at highest elevations to the mid-upper 20s.  Wind chills in the single digits and teens, except sub-zero in stronger gusts at highest elevations.

Heavier snow showers and snow squalls ( bursts of heavy snow ) will be likely during the Sunday into Monday period.  An Alert For Hazardous Travel will likely be needed.

Weather Discussion ( Winter Returns )

January-like cold will finally be returning to the mountain landscape by Thursday through this weekend, in wake of a major storm system dominated by rain and strong rises on creeks-streams.

Preliminary Storm Rainfall Totals
( January 23-24 )

City of Norton WP: 1.56″
( 5.12″ In January )

Nora 4 SSE: 1.67″

Clintwood 1 W: 1.83″

Black Mountain Mesonet: 2.90″
( 7.05″ In January )

*Widespread 1.50″ to 3.00″ storm rainfall totals were observed along & northwest-north of the High Knob Massif-Black Mountain and Tennessee Valley Divide corridor during January 23-24.  Rain mixed with snow fell at summit levels of the High Knob Massif from Monday afternoon into Tuesday AM, but with generally no accumulation ( temps near to just above freezing ).

Snowfall totals of 2-6″+ were reported within upper elevations of central-northern West Virginia ( no accumulations have yet been reported across southern Appalachian peaks ).

Strong rises occurred on creeks, with Big Stony Creek cresting only 12″ ( 1 foot ) below flood stage following between 2.00″ to 3.00″ of rain at upper elevations in the High Knob Massif.

Around 4 to 6 vertical feet of water level rise occurred on larger streams, such as the Guest River and Clinch River.

The focus now shifts toward a cold 3-7 day period upcoming.

A +PNA ( Pacific North American Oscillation ), which has been very limited in nature this winter season, will be in place to help force an eastern USA upper air trough.

Several embedded disturbances ( waves ) in the flow will drop into the upper trough over the eastern USA to trigger snow showers and flurries through this weekend into early next week.

Colder than average temperatures will dominate the 3-7 day period into early next week.  The trend beyond that time is uncertain, with ongoing changes underway amid the high latitudes involved with a displacement of the polar vortex away from the North Pole and warming in the stratosphere.  Tropospheric model volatility is expected.

Mountain Area Forecast ( Jan 21-24 )

An Alert For Development Of A Major Storm System, With Deep Low Pressure, Is Now In Effect From Late Sunday Into Tuesday Morning. 

A powerful low pressure will develop along the Appalachians by late Sunday into Monday.  Showers & thunderstorms Sunday will give way to the development of heavy rainfall Sunday Night into Monday, with significant rainfall amounts expected.

Strong rises on streams will be likely into Monday.  Folks living & driving through low-lying and flood prone locations will need to remain alert for changing conditions.

An increase in wind speeds and colder air will develop by late Monday into Tuesday, with a change from rain to accumulating snow at elevations above 3500 feet. 

Overnight Into Saturday Morning

Mostly cloudy ( high clouds ).  Areas of valley fog possible.  Winds SSW-SW at 5-15 mph, with higher gusts, on ridges & plateaus below 2700 feet.  SSW-SW winds 10-20 mph, with higher gusts, on upper elevation mountain ridges.  Temps varying from 30s to around 40 degrees in valleys to the upper 40s to low-mid 50s on gusty mountain ridges.

Saturday Afternoon

Increasing clouds with a chance for showers or steady rain by middle to late afternoon.  Unseasonably mild.  Light SE-S winds at mostly less than 10 mph.  Temperatures varying from upper 40s to lower 50s at highest elevations to the upper 50s to lower 60s.

Saturday Night Into Sunday Morning

Mostly cloudy.  Chance of showers.  SE-S winds increasing to 5-15 mph, with some higher gusts along mountain ridges by morning.  Temperatures in the 40s to lower 50s.  Areas of dense valley fog.

Sunday Afternoon

Mostly cloudy.  A chance of showers & thundershowers.  Mild.  ESE-SSE winds at 10-20 mph, with some higher gusts, especially across middle-upper elevation mountain ridges & plateaus.  Temperatures from the 40s to lower-middle 50s, coolest at the highest elevations.

Strong water level rises on streams will be possible into Monday.  Folks living and driving through low-lying, flood prone locations will need to remain alert to changing conditions.

Sunday Night Into Monday Morning

Rain developing.  Becoming windy.  Heavy rainfall totals.  Winds shifting from easterly to northerly into morning.  Wind speeds 10-20 mph, with higher gusts, on mid-upper elevation plateaus-ridges.  Dense fog ( orographic clouds ) at mid-upper elevations.  Temperatures dropping into the 40s.  Wind chills falling into the 30s in upper elevations.

Monday Afternoon

Rain & showers.  Low clouds with dense fog at elevations above 2500-3000 feet.  Patchy fog at lower elevations.  NW-N winds 10-25 mph with higher gusts.  Temperatures falling into the 30s to low-mid 40s ( coldest at highest elevations ). Wind chills dropping into the 20s & 30s.

A change from rain to snow is expected in upper elevations by late Monday into Tuesday AM.  Accumulations of 1-3″ are expected at elevations above 3500 feet, with 3-6″+ at elevations above 4000 to 5000+ feet in the southern Appalachians.  Slushy to hazardous driving conditions are expected at these high elevations.

Monday Night Into Tuesday Morning

Rain & showers.  Rain changing to snow at the highest elevations.  Winds NW-N at 10-25 mph, with higher gusts.  Dense fog at elevations above 2500-3000 feet, becoming freezing fog at elevations above 3400 feet.  Temperatures dropping into the upper 20s to mid-upper 30s ( coldest at highest elevations ).  Wind chills in the 10s and 20s ( again coldest at highest elevations ).

A storm system tracking across mid-continent will push milder air briefly back into the mountain region by the middle of next week,  before temperatures crash during late week to mark the start of a prolonged wave of cold conditions.

Weather Discussion ( Major Storm )

Saturday Night Update

The strongest low pressure of the winter season to date will be impacting the mountain region Sunday into Tuesday AM, with home barometers expected to plunge toward 29.00″ .

Any time pressure has reached that low in the past, strong winds develop as the center begins moving away with rapidly rising air pressures as air flow rushes across the mountains to fill the “void” of low pressure ( i.e., the atmosphere works to achieve balance ).

Although varying at the surface with details, models remain fairly consistent at upper levels.  Past climatology says that significant weather impacts will occur with this type of storm development, which will present an array of conditions varying from showers and possible downpours in thunderstorms Sunday to heavy rain Sunday Night into Monday.  Winds increase and air turns colder later Monday as barometric pressure begins rising rapidly as the storm center shifts east.  Rain turns to accumulating snow at upper elevations ( cold air is limited, so this will be a strongly elevation biased event with respect to snow accumulations ).

Previous Discussion

This is the “quiet” before major storm development occurs by late weekend into early next week over top of the great southern Appalachians.

The energy responsible for this major storm system is just entering the western USA, and will track eastward across the southern states this weekend.

Models are in excellent agreement with the wave developing a negatively tilted ( from NW to SE ) upper trough, with strong low pressure development from the surface upward to 500 MB by late Sunday into Monday.

A couple of different low pressure centers are currently forecast to give way to rapid development of a deep, strong low center over the southern Appalachians early Monday.  It will be important to check back as new model runs come out through the next 24-hours.

The Friday evening ( 00z ) run of the European Model has a 984 MB ( 29.06″ ) low near the Tri-Cities at 1:00 AM Monday.

Either scenario, by the NAM or European, would create a high impact upon the mountain area with strong winds and heavy to potentially excessive rainfall ( enhanced by orographic forcing along the Cumberland Mountains and TN-NC border area ).

Since the wavelength between major waves is relatively short, only a brief window of opportunity will exist from Monday afternoon into Tuesday morning for a possible transition to snow at mid-upper elevations ( forced by a combination of dynamic + upslope + advective cooling of the vertical column…before warm air advection aloft develops in advance of the next mid-continent system ).

The Bottom Line:

Major Storm Development is expected by late Sunday into Monday with deep low pressure forming over top of the southern Appalachians.  Heavy rain and strong water level rises on streams will be possible.

Folks living & driving through flood prone, low-lying areas will need to remain alert to changing conditions.  Strong winds will also develop, especially at middle-upper elevations.  In addition, a change to wet snow is being monitored for upper elevations by later Monday into early Tuesday ( with snow levels and any possible amounts yet to be determined ).

Mountain Area Forecast ( Jan 16-19 )

Several Significant To Major Storm Systems Will Be Impacting The Mountain Region During The Next Five To Ten Days, And Beyond In Time, With A Colder Trend Developing During The January 23-31 Period.

Strong rises on streams will begin to become more of a concern during this stormy pattern.  Folks living and driving through low-lying, poor drainage and flood prone locations will need to keep alert of changing weather conditions.  Stay tuned for updates.

ALERT For Dense Fog Continues Into Monday Morning

A very moist, saturated atmosphere will support widespread dense fog into Monday morning.  Visibility will drop to a quarter mile or less in the more dense areas of fog.  Caution is advised.

Overnight Into Mid-Morning Monday

Low clouds with widespread dense fog.  A chance for drizzle.  Winds SW to W at 5-10 mph, with some higher gusts, along middle-upper elevation mountain ridges.  Temperatures widespread in the 40s to around 50 degrees.

Monday Afternoon

Partly cloudy & unseasonably mild.  Winds SSW-SW at 5-10 mph, with higher gusts.  Temperatures varying from low to mid 50s in upper elevations to the lower-middle 60s.

Monday Night Into Tuesday Morning

Cloudy.  Becoming windy with a chance of showers and downpours overnight into morning.  Thunder possible.  Winds S-SW at 5-15 mph, with higher gusts, on mountain ridges & plateaus below 2700 feet.  Winds SW 15-25 mph, with higher gusts, on mountain ridges above 2700 feet.  Mild with temperatures in the upper 40s to low-mid 50s.  Dense fog redeveloping along upper elevation mountain ridges ( locally in other locations ).

Tuesday Afternoon

Low clouds.  Windy.  Showers redeveloping, with a chance of thunder ( especially by late ).  SW winds 10-20 mph with higher gusts.  Dense fog along upper elevation mountain ridges.  Temperatures from around 50 degrees at highest elevations in the High Knob Massif to the upper 50s to middle 60s ( warmest in lower elevations ).

Tuesday Night Into Mid-Morning Wednesday

Showers with a chance of thunder.  Downpours likely.  Gusty SW winds at 10-25 mph, with higher gusts, shifting WNW by morning and decreasing to 5-15 mph.  Mild through the overnight then turning colder during morning.  Temps widespread in the 50s, then dropping into the 40s and 30s during the predawn to mid-morning period ( coldest at the highest elevations ).  Areas of fog with widespread dense fog across the upper elevations.  Wind chills developing by morning with values dropping into the 20s and 30s.

Updated: Wednesday Afternoon

Partly to mostly cloudy ( cloudier toward the north and northwest of Wise ).  Chilly.  Winds WNW-NW at 5-10 mph, with higher gusts.  Temperatures varying from upper 30s to around 40 degrees at highest elevations to the mid-upper 40s to around 50 degrees ( warmer southward into valleys of the Clinch, Powell, Holston rivers ).

Wednesday Night Into Thursday Morning

Mostly clear during the evening, then increasing high altitude clouds overnight into morning.  Areas of fog possible, especially at lower-middle elevations.  A large vertical temperature spread developing between valleys & ridges.  Light & variable winds below 2700 feet.  Winds SW to WNW at 5-15 mph, with higher gusts, along mountain ridges above 2700 feet.  Temperatures varying from low-mid 20s in high valleys to the 30s, except readings rising into 40s on higher elevation ridges by predawn-morning.

The return of a colder, wintry pattern is being monitored for the January 23-31 period.  This could begin with a major storm system, featuring high winds and a heavy rainfall to high elevation snow potential.  Stay tuned for later updates.

Weather Discussion ( Active Pattern )

Wednesday Morning Update

Low clouds are breaking up along the southeast edge of a large cloud shield, so I have updated my Wednesday PM forecast to account for this current trend.

If this trend continues, afternoon temperatures will be a little milder and sunshine more abundant.  A low cloud deck will likely remain very close by, near the Virginia-Kentucky stateline, such that conditions will vary significantly over short distances along the U.S. 23 corridor.

Turbulent mixing, enhanced by mountain waves, appears to have been able to mix out a relatively narrow inversion just above the summit level of the High Knob Massif to open up clouds.  To the northwest, by notable contrast, where mountain waves are lacking, a solid deck of clouds is continuing to hold.

Monday Evening Update

A stormy weather pattern is upcoming for the mountain region during the next 1-2+ weeks.  It is important to begin highlighting this now, as the first wave will start impacting the mountains overnight into Tuesday ( the weakest wave ).

The European Ensembles remain very consistent day after day in the upcoming forecast setting, with blocking taking shape near Hudson Bay and a storm train of waves moving across the USA from west to east beneath it.

As I have already noted, many days ago, the combination of Pacific Ocean moisture ( mid-upper levels ) & Gulf of Mexico moisture ( low-levels ) with orographic forcing will make upcoming systems productive precipitation producers.  Given all the wetness of the past 7 weeks, an increasing threat for too much water will have to be respected.

As the EPO trends negative by around January 23, it will join a +PNA to help a colder pattern to develop.  Until then rain will continue to be the major precipitation form.

Previous Discussion

A very moist atmosphere continues to grip the mountain area with widespread dense fog at middle-upper elevations across Wise and Dickenson counties at the present time.

The lower atmosphere has become saturated through a deep layer.

Fog has now been dense at high elevations in the High Knob Massif for the past 6 days  Only a minor break occurred when the highest elevations got briefly above the low cloud deck.  Another break, if lucky, could occur Monday afternoon with partly cloudy skies.

An unseasonably warm air mass for this time of year is widespread across the USA and western-central Canada.

The NWS HRAP Precipitation Estimate is too low for the City of Norton and High Knob Massif area ( above ), where totals during the November 28 to January 12 period have varied from 12.80″ in the City of Norton ( official NWS rain gauge ) to as much as 18.00″ in upper elevations of the High Knob Massif.

This is part of a wet winter season pattern that has produced a general 10.00″ to 15.00″+ of total precipitation in the High Knob Massif area ( including the City of Norton ) since the beginning of December 2016 ( several inches more if including the final couple of days in November ).

Several important weather systems will be impacting the mountain region through the next week to 10 days, with number one upcoming for late Tuesday into Wednesday when gusty showers & possible thunder will give way temporarily to a drop in temperatures.

As the wet pattern rolls onward this week, signals for a major-league storm system continue to show up in models for the final week of January ( beginning around the Jan 22-23 period based upon current timing ).  This occurs as high latitude blocking develops over Canada with falling 500 MB heights to the south.  Confidence in this is increased since major changes are also expected in the stratosphere and polar vortex positioning through the end of January.

A setting like this typically produces a series of storms, so a very active pattern is upcoming into the extended that will feature a notable trend back toward wintry conditions in the final week of January.

Stay tuned for updates.

Mountain Area Forecast ( Jan 13-15 )

ALERT For Dense Fog Development Into Friday AM For Locations Along and N-NE Of The High Knob Massif & Tennessee Valley Divide

A frontal boundary will drop into the Cumberland Mountains and stall, with fluctuations in its position expected throughout the up- coming weekend.  Dense fog will tend to be persistent across high elevations, with intervals of dense fog at middle-lower elevations.  Intervals of showers will also occur, continuing this wet pattern.

Overnight Into Mid-Morning Friday

Showers developing.  Gusty SW winds shifting NNW-NNE by morning at 5-15 mph, with higher gusts.  Dense fog possible, especially at mid-upper elevations along and north of the High Knob Massif-Tennessee Valley Divide.  Temperatures dropping into the 40s.

Friday Afternoon

Low clouds.  Chilly.  Chance of drizzle or light showers.  Light & variable winds.  Temperatures in the upper 30s to middle 40s in locations along and north of the High Knob Massif & Tennessee Valley Divide ( milder to the south ).

Friday Night Into Saturday Morning

 Light rain & showers redeveloping.  Areas of fog ( dense at high elevations ).  Winds shifting SSW to WSW at 5-15 mph, with higher gusts.  Temperatures steady or rising into the middle 40s to lower 50s.

Saturday Afternoon

Showers.  Gusty.  Areas of fog ( dense at high elevations ).  SSW-WSW winds 5-15 mph, with higher gusts, below 2700 feet.  Winds SW-WSW 10-20 mph, with higher gusts, along upper elevation mountain ridges.  Temperatures varying from upper 40s to upper 50s ( coolest highest elevations ).

Saturday Night Into Sunday Morning

Showers.  Area of fog ( dense across upper elevations ).  SW-W winds 5-15 mph, with higher gusts, possibly shifting N by morning.  Temperatures widespread in the 40s to lower 50s.

*A heavy rainfall potential continues to be monitored for next week.  Strong rises on streams could occur depending upon rain amounts.  Stay tuned for later updates.

**A major pattern change back to cold, wintry conditions is being monitored for the last week of January into the start of February.  Chances for a return to a cold, wintry pattern are increasing for the longer-term period.

Weather Discussion ( Wet Pattern )

A frontal boundary will be dropping into the mountains and stalling, with the boundary being south to north of the area throughout the upcoming weekend.  This means periods of showers and a predominance of low clouds, with dense fog being persistent and long-lived across high elevations.

As the front drops into the area by the predawn-morning of Friday the first concern becomes dropping cloud bases and the possibility of dense fog formation amid locations along and north of the High Knob Massif-Tennessee Valley Divide on upsloping northerly winds.

The high-resolution NAM Model forecast’s temperatures to drop to around 40 degrees in Wise by 10:00 AM Friday.  This would also be accompanied by dense fog.  Conditions which actually develop will be highly dependent upon the position of the frontal boundary.  The colder air will be shallow, and temperatures at middle-lower elevations north of the High Knob Massif could be cooler than at highest elevations.

Rainfall amounts from Friday through this weekend will also be dependent upon the frontal position.  A currently predicted area of heavier rains just north of the area could easily be across the Cumberland Mountains with only a tiny shift in the boundary from current model projections.

*Orographics will also be a factor, such that amounts within the High Knob Massif-Black Mountain corridor are likely to be greater than models are currently forecasting ( as recently observed ).

A continued mild, wet pattern is expected into next week with a combination of Pacific moisture ( at mid-high levels ) and Gulf of Mexico moisture ( at low levels ) setting up the potential for significant rainfall across the Ohio-Tennessee valleys & Appalachians.  Timing and details, of course, yet to be resolved ( but the pattern is relatively clear ).

Major changes in the stratosphere beyond this upcoming 6 to 10 day period signals an increasing chance for a return of colder, wintry conditions across eastern portions of the USA by the final week of January into early February.

*The shift of a developing warm pool of stratospheric air across to the North American side of the North Pole, and eastward shift of the Polar Vortex off the pole, initially suggests a change back toward more typical winter conditions.

If the European group is on target, additional changes in the flow field around the vortex will then set up the return of cross-polar flow back into the USA during early February.

**Although the stratosphere is also dynamic, with many wave influences and interactions, conditions tend to be much more stable than within the troposphere and forecast’s made outward in time also tend to be more reliable than those made within the troposphere.  By no means perfect; however, often a usable precursor for upcoming tropospheric changes.