Mountain Area Forecast ( Feb 27-Mar 1 )

ALERT For Strong SSW-WSW Winds From Tuesday Afternoon Through Wednesday Afternoon

******THIS SYSTEM WILL HAVE A WIDESPREAD WIND DAMAGE POTENTIAL DUE TO STRONG OUTFLOW AND RAPID FORWARD MOVEMENT…NO SCHOOL SYSTEMS ALONG THE VA-KY BORDER SHOULD BE PLANNING TO DISMISS AT NOON – WHEN THE LINE IS FORECAST TO STRIKE ( 11 AM TO NOON ) 

The Storm Prediction Center Has Issued An Enhanced Risk For Severe Thunderstorms Wednesday ( Today ) With A Wind Damage Producing Squall Line Expected To Arrive At The VA-KY Border Around Mid-Day

*An Outbreak Of Severe Thunderstorms ( Squall Line With Possible Local Supercells In Advance Of Line ) Is Expected During Early-Mid Afternoon Hours On Wednesday. 

**Wind Damage will be the greatest threat, with a notable power outage potential.  Damaging hail and local tornado spin-ups can not be ruled out.  This is a SERIOUS Setting.

Watches & Warnings Will Be Likely – Stay Tuned To NOAA Weather Radio & Local Media For Updates

Overnight Into Monday Morning

Increasing high clouds.  SSE-S winds 5-15 mph, with higher gusts, on mountain ridges below 2700 feet.  SSW-SW winds 10-20 mph, with higher gusts, along mountain ridges above 2700 feet.  Temperatures varying from 20-25 degrees in the colder valleys to readings steady or rising into upper 30s to lower 40s along gusty mountain ridges.

Monday Afternoon

Mostly cloudy ( mid-high clouds ).  SSE-SSW winds 10-20 mph, with higher gusts.  Temperatures varying from 40s at highest elevations to the middle 50s-lower 60s.

Monday Night Into Tuesday Morning

Partly to mostly cloudy.  SSE-SSW winds 10-20 mph, with higher gusts, along mid-upper elevation mountain ridges.  Temperatures in the upper 30s to the upper 40s.

Although atmospheric conditions able to support strong-severe thunderstorms will develop Tuesday Afternoon, some parameters ( i.e., instability-moisture and lift ) will remain strongest and best defined west of the Appalachians.

Increasingly strong wind fields will develop intense shear ( storm relative helicity ) along the mountains Tuesday afternoon-night, such that a strong or severe thunderstorm can not be ruled out with activity that may move in from the west or form locally. 

Tuesday Afternoon

Partly-mostly cloudy.  Unseasonably warm.  A chance for showers & thunderstorms ( a locally strong-severe storm possible ).  Becoming windy.  SSW winds 10-20 mph, with higher gusts, below 2700 feet.  SSW-SW winds 15-25 mph, with higher gusts, along mountain ridges above 2700 feet.  Temperatures varying from middle-upper 50s at highest elevations to the upper 60s to mid 70s ( warmest downslope sites from Pound-Clintwood to Haysi-Grundy ).

Tuesday Night Into Wednesday Morning

Mostly cloudy.  Windy & unseasonably mild.  A chance for showers & thunderstorms ( a locally strong-severe storm possible ).  SSW to SW winds 15-25 mph, with higher gusts, below 2700 feet.  SW winds 20-30 mph, with higher gusts, along mountain ridges above 2700 feet.  Temperatures widespread in the 50s to around 60 degrees.

A spring severe weather day is on tap for Wednesday with  potential for an Outbreak of Strong-Severe Thunderstorms across the Tennessee Valley and southern Appalachians.

Wednesday Afternoon

Windy with showers & thunderstorms developing.  Storms could be strong to severe with damaging winds.  Downpours likely.  Hail possible.  Winds SW at 15-30 mph, with higher gusts.  Temperatures varying from 50s at highest elevations to the mid-upper 60s.

Much colder air is again expected Thursday-Friday ( March 2-3 ) with widespread below freezing temperatures and wind chills.

Weather Discussion ( In Like A Lion )

Monday Afternoon Update

While Wednesday ( March 1 ) is clearly going to be THE DAY when all ingredients converge toward an outbreak of severe thunderstorms along the mountains, a strong-severe storm can also not be ruled out beginning Tuesday afternoon for locations along and west of the Cumberland Mountains and Cumberland Plateau ( SE Kentucky and Tennessee ).

Winds Monday have been a little stronger and temps a bit cooler than my initial forecast, amid an ominous looking haze in late February at the conclusion of Meteorological Winter.

Perhaps that ominous look from the CAM extends from the many graphics I have been viewing showing conditions that become favorable for tornadoes on Wednesday, with an inverted-V sounding and twisting storm slinky’s forecast vertically above Wise County and the City of Norton.

*The above just being chosen points, as these conditions will extend across a large region.

If these trends continue, then a RARE Enhanced Risk of Severe Thunderstorms ( rare for the end of Meteorological Winter and Dawn of Meteorological Spring ) may be issued over or very close to the mountain area by the SPC during Wednesday ( with a Tornado Watch ).  Stay tuned for updates on this developing severe weather threat.

Reference Major Severe Outbreak Of March 2012 to review a setting that occurred 5 years ago at the beginning of March.

Previous Discussion

An increasing pressure gradient will crank up strong winds to usher in the month of March, which is literally looking to ROAR into the mountain region.

A strong wind field will generate ROARING SW winds into the mountains starting later Tuesday into Wednesday.

Parameters for severe thunderstorms will then need to be closely monitored into the afternoon hours:

SLIM: Shear-Lift-Instability-Moisture

Storm relative helicity values are currently forecast to be notable ahead of a strong cold front, along with some CAPE ( Convective Available Potential Energy ) and increasing moisture.

While the Storm Prediction Center already has the region outlooked for potential severe thunderstorms, this will be better defined and adjusted during the next couple of days.

The Bottom Line…

March 2017 will literally ROAR into the mountains on strong SW winds.  Increasing moisture-instability will combine with shear to set the stage for strong-severe thunderstorm development ( highest threats west of the mountains Tuesday and along the mountains and Tennessee Valley during Wednesday ).

Stay tuned to NOAA Weather Radio and your favorite media sources for updates, possible watches and/or warnings which may be needed Tuesday-Wednesday.

Mountain Area Forecast ( Feb 25-27 )

A Slight Risk For Severe Thunderstorms Will Exist During The Overnight-Predawn Of Saturday – Strong Damaging Winds & Hail Will Be The Primary Threats

Overnight Into Mid-Morning Saturday

Showers & thunderstorms developing.  Some storms may be strong to locally severe.  Downpours likely.  S-SW winds 10-20 mph, with higher gusts, shifting W by morning.  Temps in the 50s and 60s during the early overnight ( 40s in colder mountain valleys will be rising ) dropping into the 30s and 40s into morning ( coldest at highest elevations ).

Saturday Afternoon

Becoming partly cloudy.  Much cooler.  W-WNW winds 10-20 mph, with higher gusts.  Temperatures falling into the 30s to lower 40s by sunset at lower-middle elevations and into the 20s at highest elevations.  Wind chills plunging into the 20s & 30s, except into 10s at highest elevations, by late PM.

Saturday Night Into Sunday Morning

Mostly clear.  Cold.  WNW winds 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges-plateaus.  Temperatures varying from mid-upper 10s to mid-upper 20s.  Wind chills in the single digits and 10s along gusty mountain ridges ( near 0 degrees highest elevations ).

Sunday Afternoon

Mostly sunny.  Seasonably chilly.  Light & variable winds.  Temps varying from low-mid 30s at highest elevations to the mid-upper 40s.

Sunday Night Into Monday Morning

Increasing high clouds.  SSE-S winds 5-15 mph, with higher gusts, on mountain ridges below 2700 feet.  SSW-SW winds 10-20 mph, with higher gusts, along mountain ridges above 2700 feet.  Temperatures varying from 20s to lower 30s in colder valleys to readings steady or rising into upper 30s to middle 40s along gusty mountain ridges.

Weather Discussion ( Up And Down )

A squall line or broken line of strong to potentially severe thunderstorms will rumble into the mountains during the overnight-predawn hours of Saturday.

Typically, in February, weakening would be most likely and while it may still occur…due to a strong temp gradient and wind fields this can not be counted on and everyone should remain alert to NOAA Weather Radio and your favorite media sources for possible watches-warnings.

A very strong temperature gradient, with 850 MB readings at 11:00 PM Friday varying from +8 Celsius ( 46 degrees F ) over western Kentucky to -8 Celsius ( 18 degrees F ) across western Illinois, has developed along and behind a band of showers and strong-severe thunderstorms ( below ).

Midnight temperatures on the Kentucky Mesonet as high as 72 degrees in Booneville of Owsley County are in contrast to middle 40s in far western Kentucky ( midnight temps in the 40s are also occurring in local mountain valleys which will result in a crazy rise into the predawn followed by a strong drop after sunrise into mid-morning behind the storms ).

Strong temperature rises are likely in local mountain valleys as turbulent mixing increases ahead of the squall line and cold front to recouple them with strong boundary layer winds ( i.e., valleys with calm winds currently will turn gusty with strong temp rises ).

Despite the mildness of February 2017, and spring sights, a colder pattern is looking to return for perhaps a longer stay than just this weekend.  Warming into the middle of next week will be followed by colder conditions as March begins.

Upper air troughing into the eastern USA, and late season cross-polar flow, is currently being predicted to develop during early March ( above ) to produce temperatures that are colder than average ( below ).

So as most everyone knows, it is far too soon to even think about planting anything tender.  Native vegetation which is beginning to bloom will not be hurt as severely as cultivated or non-native species not acclimatized to such conditions.

Mountain Area Forecast ( Feb 16-18 )

Wednesday Evening Into Thursday Morning

Partly cloudy ( high clouds early, then increasing mid-level clouds toward morning ).  WNW-NW winds 5-15 mph, with higher gusts, on mountain ridges-plateaus below 2700 feet.  NW winds 10 to 20 mph, with higher gusts, upper elevation mountain ridges.  Temperatures varying from the upper 10s to the mid-upper 20s.  Wind chills in the 10s & 20s, except in single digits along upper elevation mountain ridges.

Thursday Afternoon

Becoming partly cloudy.  W-WNW winds 5-15 mph, with higher gusts.  Temperatures varying from low-mid 30s in the upper elevations to the lower-middle 40s.  Wind chills mainly in the 20s & 30s ( upper 10s to around 20 degrees along highest mountain ridges ).

Thursday Night Into Friday Morning

Mostly clear.  Windy along high ridges.  SW winds 5-15 mph, with some higher gusts on mountain ridges-plateaus below 2700 feet.  SW-W winds increasing to 15-25 mph and gusty along upper elevation mountain ridges.  Large vertical temp spread from upper 10s to lower 20s in colder valleys to the lower-middle 30s along exposed ridges-plateaus.  Wind chills in the 10s & 20s ( coldest along high ridges ).

Friday Afternoon

Mostly sunny.  Milder.  SSW-WSW winds 5-15 mph, with higher gusts.  Temperatures varying from middle-upper 40s to the middle-upper 50s ( coolest at highest elevations ).

Friday Night Into Saturday Morning

Partly-mostly clear.  Generally light winds, except SW-W at 5-15 mph, with higher gusts, on upper elevation mountain ridges.  Temperatures from 20s in colder valleys to the mid-upper 30s ( wind chills 20s-low 30s high mountain ridges ).

A period of rain will become likely later Saturday into Sunday.  A mild pattern will follow during much of next week.  Wintry air is not currently expected to return until final days of February into early March.  Stay tuned for updates.

Weather Discussion ( Spring Snow )

Winter wonderland conditions developed at middle to upper elevations into early Wednesday as a fast hitting storm system dropped a period of heavy, wet snow.

A general 2″ to 4″ of snow fell above 2500 feet in Wise County and the southern portion of Dickenson County.  As expected, little to no accumulation occurred below 2000 feet ( the exception being within mid-upper portions of Powell Valley where enough lift to support some sticking occurred down to around 1600 feet = the observed difference between 1600 feet under rising air and 1600 feet under sinking air in Clintwood where no sticking occurred ).

*And it is important to not forget northern Scott County where numerous families live above 3000 feet in the High Knob Massif where significant snow accumulated.  This is often a “forgotten” area in terms of official forecasting.  It is hoped that eventually forecasts will include this area north of the Clinch River.

It would be easy to identify it by saying northern Scott County or “north of the Clinch River” to clearly identify this area of highest terrain in Scott.

Preliminary Snowfall Reports

Clintwood 1 W: Trace
( 0.40″ with no snow accumulation )

City of Norton Water Plant: 0.5″
( 0.44″ of total precip / 6.60″ in 2017 )

Nora 4 SSE On Long Ridge: 1.9″
( 0.37″ water content with 2″ on ground )

University Of Virginia At Wise
( 0.37″ water content with 2″ on ground )

High Chaparral of High Knob Massif: 3.0″
( 3″ of wet snow on ground )

Eagle Knob of High Knob Massif: 4.5″
( 4″ of wet snow on ground )

Total snowfall amounts above 3000 feet in the High Knob Massif were held back some by freezing rain-sleet that fell with temps hovering around 30 to 32 degrees into the early overnight.

That was the only error in my forecast, with evaporative cooling in the vertical column not being able to overcome an apparently thin layer of above freezing air around 800 MB.

Reference 021317 Forecast & Discussion for my prestorm forecast.

Although some rime did accumulate in upper elevations, it was wet snow that really stuck to trees-bushes-power lines and about anything else at the elevation of the High Chaparral community.

As expected, roadways became hazardous with the initial freezing rain-sleet in upper elevations followed by a period of wet, heavy snow.  John Varner, veteran VDOT snow plow driver, reported 3″ of snow on State Route 160 near the VA-KY stateline on Black Mountain.

The ERROR in the Lonesome Pine Airport temperature sensor showed up well with 2″ of accumulation on almost everything as the LNP temp was never below 34 degrees.

NWS Cooperative observers Wayne & Genevie Riner, at nearly the same elevation as Lonesome Pine Airport, on adjacent Long Ridge of Sandy Ridge measured the same amount of snow as reported at UVA-Wise…BUT with an accurate air temp of 31-32 degrees.

The air temperature at Nora 4 SSE at 2650 feet, as well as the MIN recorded at UVA-Wise, reveals yet again the temp error at Lonesome Pine Airport that has now been observed for years ( but it is typically not noticed by most until these “marginal” settings occur – however, I would think pilots might be interested to have the correct air temperature ).  Time has come to CORRECT this error.  Let’s get it done!

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.