My Forecast For Today ( March 9 )

Reference my 030816 Forecast for the first spring photos.

A large vertical temperature spread, which is typical during much of the year in the mountains, will continue to be a prevalent factor tonight and again tomorrow night ( perhaps to a lesser degree by Wednesday Night into Thursday if wind speeds can increase enough to generate better vertical mixing ).

Overnight Into This Morning

Variable clouds ( intervals of high altitude cloudiness ).  Gusty across mid to upper elevation ridges-plateaus.  S-SW winds 5-15 mph, with higher gusts, below 2700 feet.  Winds SSW-SW 10-20 mph, with higher gusts, on mountain ridges above 2700 feet.  Temperatures varying from the 30s within colder mountain valleys to the upper 40s to middle 50s on exposed mid-upper elevation ridges-plateaus.

This Afternoon

Hazy sunshine & high clouds.  Unseasonably warm.  Winds S-SW 5-15 mph, with higher gusts.  Temperatures varying from 60-65 degrees at upper elevations to the upper 60s to middle 70s ( coolest at highest elevations ).

Tonight Into Thursday Morning

High altitude clouds.  Gusty across mid to upper elevation mountain ridges & plateaus.  SSW-SW winds increasing to 10-20 mph, with higher gusts, on exposed ridges-plateaus below 2700 feet.  SW winds 15-25 mph, with higher gusts, across upper elevation ridges.  Mild with widespread temps in the lower 50s to lower 60s on mid-upper elevation ridges and plateaus verses upper 30s to lower 40s in sheltered valleys protected from gusty winds.

Showers, with a chance for thunderstorms, will become likely Thursday Night into Friday.  Local downpours may be possible.

Weather Discussion ( March 8-9 )

Although pollen like this is not yet being generated, neither are such flowers, there is and will be increasing amounts of pollen from maple, willow, and various other species in the air during this unseasonably warm spell of early spring.

Pollens which actually can not be seen with the naked eye are the ones which tend to cause most of the misery to those who suffer.

Strong temperature inversions, with cold air drainage into mountain valleys, tend to hold back the pollen season some in the mountains ( as it does along chillier upper elevation ridges ) if you live in these naturally cooler locations.

Thermal belt sites, with colder air beneath them ( especially at night ) as well as above them, are the most favored places for surges of early season pollination.  In this area thermal belts are typically found upon middle elevation ridges and plateaus at elevations somewhere between 2000-3000 feet.

As I have written about many times in the past, pioneers were the first to discover thermal belts in the mountains and quickly began locating orchards and other frost sensitive crops in these sites.  I will have much more on such microclimatology in weeks ahead.

Focus now shifts to a slowly increasing moisture regime with models showing a significant spike upwards in total water amid the atmosphere by Thursday Night into Friday.

The precipitable water value above the Wise gridpoint at 7:00 PM Tuesday was only 0.30″ on the NAM 12 KM Model analysis.  That means if all the moisture between the surface and top of a vertical column were to be precipitated out it would generate a depth of 0.3″ on the surface.

We can judge the amount of water in the atmosphere by using a quantity known as precipitable water, which is a measure of all the moisture in a vertical column between the surface and upper troposphere ( if precipitated directly out the depth of this water on a surface would identically equal the PW value ( Precipitable Water value ) ).

Computer models can quickly calculate these values by using calculus & integrating the dewpoint ( or saturation mixing ratio ) between the surface and top of the troposphere ( where moisture typically becomes a minimum ).  Integration, of course, yielding  by definition a summation whose value = the PW value for any given vertical column of air above a given gridpoint or interpolated point amid the larger-scale forecast grid.

The NAM 12 KM Model ( above ) predicts a rather dramatic increase in PW values between now ( very dry air ) and late Thursday into Friday morning when values rise to around 1.50″ ( moderately high for any given time of year ).

While PW values are always important, they also need to always be looked at with respect to mean climatological values for the time of year.

For example, mean monthly PW values for March between the surface and 500 MB are roughly around 1.20″ ( closer to 1.00″ during early March ).  So if a 1.50″ PW value develops into early Friday it will be approximately 20% to 30% above average for this time of year.

By comparison, the current PW values at 7:00 PM Tuesday was only 25% to 30% of average for this time of year ( approximately 4 times below average for early March ).

Another forecast factor I like to look at is the thickness of the atmosphere between the surface and 500 MB.  Heavy rain often has a preferred thickness range within which climatology shows that it tends to fall during any given time of year.  Early March preferences for this mountain region being roughly around 556 dkm ( +/- ) 5 dkm.

In other words, the vertical depth of the atmosphere between the surface and 500 MB tends to be around 5,560 meters give or take some 500 meters ( 551 to 561 dkm ).  The forecast above by 1 AM Friday is a little higher than the preferred thickness here, at around 565 dkm or 5,650 meters ( by contrast, the thickness predicted over Arkansas is within the preferred range ).

Looking strictly at the above, one might say that rainfall will become likely ( with local downpours possible ) but not yet within the preferred range for widespread heavy rain.  Remembering, most importantly, the above is a forecast and this will need to be followed and adjusted accordingly as time for rain to occur gets closer.

The latest European 9 KM Model run is keeping the bulk of heavier rain well to the north and west of the Mountain Empire through Saturday Morning.  A trend to follow.

There are many other factors that forecasters should look at to form the complete picture, with the above being only  a glimpse into how moisture values should be considered.

***An important note is that when convection is able to form it can compensate for lower PW values, at any given point or time, via inflow which tends to concentrate PW values and increase them over localized areas ( thus greatly complicating what might seem to be a rather clear-cut way of forecasting rainfall intensity ).  Superimposed upon a boundary or favorable topography adds more layers to this “rainfall equation.”

Have a great Wednesday.

My Forecast For Today ( March 8 )

Overnight Into This Morning

Mid-high altitude clouds.  Large vertical temperature spread between cold valleys and windy mountain ridges and plateaus.  SW winds 10-20 mph, with higher gusts, below 2700 feet.  SW-WSW winds 15-25 mph, with higher gusts, on mountain ridges above 2700 feet.  Temperatures varying from upper 20s to lower 30s in colder mountain valleys to the upper 40s to middle 50s on exposed middle-upper elevation ridges & plateaus.  Wind chills in the 30s and 40s ( coldest along high elevation ridges ).

This Afternoon

Hazy sunshine through high altitude clouds.  Warm.  Winds SW-SSE at 5-15 mph, with some higher gusts.  Temperatures varying from mid-upper 50s in upper elevations to the mid 60s to around 70 degrees.

Tonight Into Wednesday Morning

Variable clouds ( intervals of high altitude cloudiness ).  Gusty across mid to upper elevation ridges-plateaus.  S-SW winds 5-15 mph, with higher gusts, below 2700 feet.  Winds SSW-SW 10-20 mph, with higher gusts, on mountain ridges above 2700 feet.  Temperatures varying from the 30s within colder mountain valleys to the mid-upper 40s to low-middle 50s on exposed mid-upper elevation ridges-plateaus.

Weather Discussion ( March 7-8 )

The first true signs of the spring season are slowly starting to emerge amid the mountain area, with increased singing of birds, choruses of frogs, and a few wildflowers.

I found the first Coltsfoot poking up through the leaves near the UVA-Wise Wetlands, during late on Monday afternoon, amid nice songs from male Red-winged Blackbirds ( Agelaius phoeniceus ).

The UVA-Wise Wetlands are part of a restoration project designed to capture, filter, and clean acid mine drainage before it enters the main watershed draining into the Clinch River.

The Wetlands At UVA-Wise

Weather conditions Monday were certainly much different from that observed Saturday, when big flakes of snow fell and covered highest elevations in the High Knob Massif.  I caught only a few good scenes in between showers of snow and snow-sleet.

The U.S. Forest Service is proposing a large burn ( 1122 acres ) and timber cut that will impact 50% of the 7464 acres stretching across the Clear Creek, Machine Creek, Burns Creek, and a small part of the Mill Creek basins in the High Knob Massif.

Some blemishes in the photographs are actually flakes of snow, as I captured a few images in between the showers of heavier snow.

The understory is rather lush in portions of the proposed burn.

Since everyone owns this land, everyone is encouraged to voice their opinions on this large burn and timber cut proposal.

The weather focus tonight is on another large vertical spread in temperatures between cold, frosty valleys and gusty mid-upper elevation mountain ridges & plateaus.

Temperatures at 4:00 AM varied from upper 20s to lower 30s in colder valleys to the 50s on gusty middle elevation ridges.

The big news in the weather world today is the introduction of a major upgrade to the Integrated Forecast System, called the European Model.  The 12z Model Run this morning will be the first to publicly show this new upgraded package.

The statistically best medium range forecast model on the planet will be getting better according to testing preformed during the past few months on this new upgrade that will take the resolution down to 9 KM ( from 16 KM ) for the operational global group.  The unique 4-D system will utilize a octahedral reduced Gaussian grid, which will make running the model less costly while conserving general efficiency ( according to released testing results ).

The coming months should prove interesting as all eyes focus on how this new upgrade preforms under the rigors of daily global weather forecasting.  I will be most interested in watching if it will be able to better resolve the orographics and patterns which are specific to the Appalachian Mountains ( verses the current ).

*Mathematical statistics verify that the European Model has been the best medium range model for decades.  Although it struggles, like all models, at times the mathematics do not lie and clearly show that the 4-Dimensional System used by this model has been superior to all other models, especially for locations dealing with baroclinicity at middle to high latitudes.

 Meanwhile, a mild weather pattern will dominate this week with abundant clouds at high altitudes that will trend lower by late week into this weekend-next week as moisture will be increasing & eventually producing showers-storms.

Have a great Tuesday.

My Weekend Forecast ( March 5-6 )

Reference my 030416 Forecast for details on this past day.

ALERT For Dense Fog & Freezing Fog At Mid-Upper Elevations Along & North Of The High Knob Massif Tonight Into Sunday AM – Mainly Above 2700 Feet

Some freezing fog coated higher elevations around Norton-Wise into Saturday morning, with another round of dense fog expected to develop overnight into Sunday morning with freezing levels at the 2000 to 2500 feet elevation by morning ( new models tonight have lowered the freezing level by a few hundred vertical feet ) as deep northerly flow develops into Sunday morning.  This will also support some snow showers across upper elevations and drizzle and/or freezing drizzle-snow-mix at middle elevations and just drizzle at lower elevations ( mainly north of High Knob Massif ).

*This will develop on northerly upslope flow with downslope sites mainly having dry and mostly cloudy conditions.

*Snow fell hard, with big flakes, between 3:00 to 4:00 PM and covered roads at highest elevations for a time before melting  some, as the temperature hovered between 32 to 33 degrees.

While a rain-snow mixture fell in Norton-Wise during Saturday afternoon, mostly all snow fell at summit levels of the High Knob Massif with around 0.5″ accumulating on Eagle Knob through late afternoon ( new snow accumulation shown above ).  Tonight very dense fog ( freezing fog ) has settled into the high country with dropping cloud bases expected into middle elevations after Midnight into Sunday morning.  Slow down and take it easy.

Saturday Forecast

Mostly cloudy skies overnight will carry into this morning, with some breaks possible.  This has allowed dense fog to develop with temperatures below freezing.  Light northerly winds will shift SW-SSW by morning on middle to upper elevation ridges and will eventually help dissipate the fog.

Any sunshine will be limited today as mid to high altitude clouds begin increasing in advance of the next fast moving system.  Morning temperatures in the 20s to near 30 will have a chance to rise into the 40s across much of the area before afternoon rain showers develop.  The exception will be at higher elevations in the High Knob Massif where 30s prevail, with snow or a rain-snow mix being possible there.

*As it turned out sleet & snow, with a little rain mixed, fell in the 3000-3500 foot elevation zone with nearly all snow above 3500 ft.

Saturday Night Into Sunday Morning

Following late afternoon-early evening melting off roads, it took little time for snow to recover roadways at high elevations in the High Knob Massif during Saturday Night with another burst of heavy snow ( with riming in clouds and temps in the 20s on N winds producing wind chills as cold as the low-mid 10s ).

Winds will shift NW-NNE behind a cold frontal passage on Saturday evening, with rain showers becoming mixed with or changing to snow in middle elevations, and all snow at upper elevations.  Any snow accumulations, with up to 2″, look to be mostly above 2700-3300 feet in elevation.

A lowering of cloud bases will need to be watched for overnight into Sunday morning on northerly upsloping winds of 5-15 mph, with higher gusts, across mid-upper elevation mountain ridges-plateaus ( in typical locations along and north of the High Knob Massif and Tennessee Valley Divide…such as Wise, Sandy Ridge and adjacent communities which typically have dense upslope fog ).

Freezing fog will be possible at elevations above 2700 feet, with drizzle-freezing drizzle and/or some snow-mix at the lower-middle elevations and snow showers above 3000 ft.

Mid-Morning Sunday Through Sunday Afternoon 

Cloud bases are expected to lift and drier air is currently predicted to overspread the area into the afternoon with skies becoming sunny to mostly sunny.

Winds will become light and temperatures should rise into the 40s to low-mid 50s ( upper 30s to lower 40s over a little snow at highest elevations in the High Knob Massif ).

Sunday Night Into Monday Morning

Some mid-high clouds will be possible as winds will be shifting SSE-SW at 5-15 mph, with higher gusts, across middle-upper elevation mountain ridges & plateaus.

This wind shift marks the beginning of a long awaited warming trend, with temperatures rising at highest elevations overnight into Monday morning.

*Due to an increase in wind chills, this initial warming will not really be felt along mountain ridges ( that comes next week ).

Updated at 9:45 PM on Sunday – March 6, 2016

A large vertical temperature spread, as I originally expected, will develop through tonight into Monday morning with readings varying from frosty, cold 20s  within mountain valleys to upper 30s & 40s across exposed mountain ridges & plateaus ( where the off-setting factor will be an increase in wind chills, especially amid upper elevations where SSE-SSW winds are already gusty ). 

Weekend Summary

Seasonably cold conditions will continue to be felt through most of this weekend before a prolonged warming trend develops next week.

Clouds will remain abundant through Sunday AM, with another fast moving disturbance expected to spread rain and snow showers across the area from Saturday afternoon into Saturday night.

Any sticking snow is likely to be restricted to highest elevations, above 3300 feet in elevation ( dusting up to 2″ or so will be possible at these highest elevations ).

A period where cloud bases will drop needs to be respected by the Midnight-Sunrise period Sunday, when northerly upslope flow will develop.

A period of dense fog, with freezing fog above 2700 feet, will become possible at mid-upper elevations along and north of the High Knob Massif during a period between 10 PM Saturday & 10 AM Sunday.

The elevation of cloud bases ( dense fog ) and the freezing level will need to be updated later as this period gets closer in time.

The main idea being that cloud bases will drop again on upslope flow during late Saturday evening into Sunday morning, with riming and dense fog at upper elevations along and north of the High Knob Massif-Tennessee Valley Divide which may drop into middle elevations ( below 3000 feet ) for a period of time.

Cloud bases are expected to lift and finally dissipate  to produce mostly sunny to sunny skies into Sunday afternoon.  This will allow temperatures to rise into lower-middle 50s in milder locations, with 40s most likely across upper elevations ( coolest over snow at highest elevations and northern slopes within the High Knob Massif ).

A large vertical temperature spread will be likely to develop Sunday Night into Monday morning as winds shift southerly to begin a long awaited and prolonged warming trend.  This will be indicated first at highest elevations where temperatures will tend to rise, after any initial evening declines, overnight into Monday.  Mountain valleys, by contrast, will have temp drops and develop much colder conditions than breezy to gusty ridges ( the offsetting factor for high ridges being an increase in wind chills into Monday AM ).

Extended Look At Next Week

An unseasonably warm period of weather, via a major shift in the upper air flow regime across the USA, is on tap for next week.  Eventually, this will include rises in humidity-dewpoint ( moisture ) levels and showers-thunderstorms ( by late next week-next weekend ).

The eastern USA trough is going to be replaced by ridging as the western ridge breaks down and gives way to troughing.

This will bring needed precipitation to California and will set up a pattern featuring an excessive rainfall potential across the Lower Mississippi Valley.  The eastward extent initially being blocked by ridging in the Atlantic; however, over time this will likely give way enough to allow for rains to move into the Ohio-Tennessee valleys and Appalachians.

This will be such a warm period that it should trigger the first woodland wildflowers of the season to emerge, if not already in milder locations outside the mountains, such as Coltsfoot ( Tussilago farfara ) and Trout Lily ( Erythronium americanum ), along with a few other species.  Enjoy.

For those who suffer from pollen, it should also begin to increase some early tree pollens ( such as maples and the willows ) at lower-middle elevations.

Have a great weekend.

My Forecast For Today ( March 4 )

State Route 619, Routes 237 & 238, as well as others, are icy and snow covered in upper elevations of the High Knob Massif.  Use caution if traveling overnight into morning in this area and at other elevated locations in the area which had sticking snow.  Visibility ( with freezing fog ) is also very low above 3000 feet.  

Otherwise, with temperatures at or below freezing, patches of black ice could form on other surfaces and with freezing fog across upper elevations above 3000 feet.

Overnight Into Mid-Morning

A chance of flurries & light snow showers.  Drizzle possible.  Cold & damp.  Winds shifting NW to NNW at 5-15 mph, with higher gusts, overnight into morning.  Temperatures in the 20s to lower 30s.  Wind chills in the 10s and 20s on exposed mid-upper elevation mountain ridges.  Freezing fog with rime formation at elevations above 3000 to 3300 feet.

Mid-Morning Through This Afternoon

Any flurries-drizzle ending.  Chilly.  Decreasing clouds by mid to late afternoon.  NW winds 5-10 mph, with higher gusts, on mid-upper elevation mountain ridges & plateaus.  Temperatures varying from lower 30s to the lower-middle 40s, coldest at highest elevations.  Wind chills in 20s & 30s.

Tonight Into Saturday Morning

Chance of an early evening sprinkle or snow flurry.  Partly to mostly cloudy in the evening with increasing mid to high altitude clouds overnight into morning.  Winds SW-W at less than 10 mph in most places ( a few higher gusts along mid-upper elevation ridges ).  Temps in the 20s to lower 30s.

Weather Discussion ( March 3-4 )

Afternoon Update

Many mountain wave induced breaks have occurred amid an otherwise persistent overcast this afternoon, with temps varying from around 30 degrees on High Knob to the lower 40s in portions of the Clinch & Powell river valleys.

The only change in my forecast being to skies for this evening, with partly-mostly cloudy conditions now expected with just a chance for a passing sprinkle or snow flurry.

Breaks have occasionally illuminated the beautiful rime capping the sprawling High Knob Massif.

Mountain wave breaks began developing by mid-morning and have increased this afternoon.

Snow depths of around 1″ were reported above 3200 feet in the High Knob Massif this morning, from 0.5″ measured in High Chaparral by my friends Joe & Darlene Fields to about 1″ or a bit more at the summit level.

My friends Wayne & Genevie Riner measured 0.3″ of snow at their official NWS station on Long Ridge of Sandy Ridge as PM temperatures struggled to reach the middle 30s.

The PM Max officially reached 39.7 ( 40 ) degrees in Clintwood.

My Overnight Discussion

Although around 1″ of snow looks to have accumulated at highest elevations in the High Knob Massif, there was little sticking in most places as the mountain area got caught in between a snowband to the north and heavy rain-storms across the Deep South.  That was the main reason I did the afternoon downgrade for this area.

Reference my 030316 Forecast for more details on the past day.

When I saw that setup I knew this area would be getting limited snowfall with air sinking adjacent to the snowband toward the north and around the rain-thunderstorms to the south.

Up to 7″ of snow has been measured within the main band of snow that set up over northeastern Kentucky amid the JKL National Weather Service Forecast Office’s coverage area, with public reports as high as 9″ .

Note the U.S. GFS Model forecast on the 1:00 AM Thursday run did not even have any snow forecast over the area that got the most snow.  The following 7 AM run ( below ) was not much better.

The 7 AM Thursday run of the NAM Model group did have a somewhat better handle on placement of the snow, with  the northeastern Kentucky snowband appearing ( although still forecast to be much weaker than it turned out to be ).

It was not until the snowband was already forming that the high-resolution NAM 4 KM Model finally was able to resolve it somewhat better; although, still not precisely.

The European Model did the best of all models as it did pick up on the northern-northeastern Kentucky snowfall enhancement, but had struggled with placement and amounts.  Most importantly, for this area, it over-estimated snowfall along the mountains at the expense of snowfall in the lowlands of the foothills.

I show the above to illustrate the problems that models have trying to resolve some systems ( especially those possessing separated pieces of energy and/or amid a transitional state before intensification.  This weather system had both these factors going, and more ).

Last night I made an excellent forecast based upon the data at hand, including that of the European Model, which I had used along with the high-resolution NAM to develop a elevation zone break-down in amounts.

The problem, of course, precipitation never did develop as it was forecast by models over this area as atmospheric compensation had to occur for all the air converging at low-levels and rising upward through the atmosphere to crank out snow amid the lowlands to the north.

When air converges and rises over one region it typically will sink into adjacent zones in order to conform to the atmospheric-fluid dynamics principle summarized by the basic Law Of Conservation Of Mass.  This occurs all the time locally, with showers or squalls of rain-snow and throughout the convective ( thunderstorm ) season.  It also is forced throughout the orographic season by the mountains, with formation corridors possessing rising and sinking air.  Remembering always, of course, that this is four dimensional in nature ( i.e., it possesses two horizontal wind components, a vertical wind component, and time ).

Looking ahead, one more weak system passes later Saturday before a significant warming trend to spring levels kicks in to dominate next week.  Eventually, this will crank up the spring thunderstorm machine.

( No, I do not think this is the end of winter.  With good chances for more accumulating snow, especially at higher elevations, before the record books close on this Winter Season of 2015-16 ).

Have a great TGIF.

My Forecast For Today ( March 3 )

Updated At 3:00 PM:  My ALERT For Any Significant Snow Accumulations Is Cancelled – Some Snow Is Possible Tonight-Friday Morning But Amounts Are Expected To Be Light ( Generally Less Than 1″ ).

A band of persistent snowfall had developed from northeastern Kentucky into western-southern West Virginia and will now be the focus of heaviest snowfall amounts during this event in our region

ALERT For An Accumulating Wet Snowfall Developing This Afternoon Into Tonight – All Snow Is Likely Above 2500 to 3000 Feet, With A Mixture Possible Below 2000 to 2500 Feet…Before Changing To All Snow.

Rain and snow will develop across the area this afternoon into tonight, with the elevation of the sticking snow level yet to be determined for this afternoon in locations along and north of the High Knob Massif.  A mix or rain will be likely in the Powell Valley to Big Stone Gap corridor on downsloping winds off the High Knob Massif.

Overnight Into This Morning

Partly-mostly clear evening skies giving way to increasing clouds into morning.  Light SSE-SSW winds at generally less than 10 mph on mountain ridges below 2700 feet.  Winds S to W at 5-15 mph on upper elevation ridges.  Temps varying from the upper 10s to the upper 20s, with readings tending to rise into morning, especially at high elevations.

This Afternoon

Cloudy with rain & snow developing.  All snow above 2500 to 3000 feet.  A mixture possible at lower elevations, with a mixture likely within the Powell Valley to Big Stone Gap corridor.  Winds ESE-SSE at 5-10 mph, with higher gusts, along middle elevation mountain ridges & plateaus.  SE-S winds 10 to 15 mph, with higher gusts, in upper elevations.  Temperatures in the 30s to around 40 degrees before a drop into the 20s to low-mid 30s after precipitation onset.  Wind chills in the 10s & 20s exposed mid-upper elevation ridges.

Tonight Into Friday Morning

Snow at mid-upper elevations.  A mix changing to all snow at lower elevations.  Winds becoming NW-NNW at 5-15 mph, with higher gusts, overnight into morning.  Temperatures in the 20s to lower 30s.  Wind chills in the 10s and 20s on exposed mid-upper elevation mountain ridges.

Snowfall Forecast – Thursday PM to Friday AM

1″ or less at elevations below 1500 feet

1″ to 2″ at elevations of 1500-2500 feet

2″ to 4″ at elevations of 2500-3500 feet

4″+ possible at elevations above 3500 feet

Target Snowfall of 2″ in Norton-Wise ( +/- ) 1″ spread potential.  This implies a general 1″ to 3″ of snow possible.  Locally higher amounts will occur if precipitation is all snow, while amounts could be less if more mix occurs.

*If an easterly component to the low-level flow develops, snowfall will be less than 1″ in the Powell Valley to Big Stone Gap corridor and into portions of Lee County.  If a TIM Circulation should form precipitation amounts could be enhanced in the Norton-Big Stone Gap corridor, with more snow on the cold side of the boundary and enhanced rain on the warmer, sinking air side of the circulation.

Weather Discussion ( March 2-3 )

My Afternoon Update

Precipitation echoes have been over top the area since early this morning but little to nothing ( even sprinkles or flakes ) have reached the surface.

Much of the Mountain Empire has been caught in between main precipitation bands, one to the south with rain-storms and another which has set up from NE Kentucky into West Virginia.  So I have cancelled my ALERT for any significant snowfall.  The Winter Weather Advisory officially remains in effect into Friday AM.

The latest high-resolution NAM 4 KM Model seems to have picked up on the trend and placement of snowfall amounts.

“You have to know when to hold them, and when to fold them,” says Kenny Rogers, so in this case I am folding with respect to significant snowfall.  Some snow may still occur but generally accumulations are likely to be less than 1″ in most places.

The forecast in words will remain unchanged, just snowfall amounts will be much less than expected.  This is the update I was somewhat expecting from last night ( to either go up or down in amounts, amid this middle zone ).

My Overnight Discussion

Reference my 030216 Forecast for more details on the past day.

Flurries and snow showers developed overnight as colder air poured into the mountains with just enough sticking to coat roadways across the High Knob Massif and in a few other elevated locations.

Nice rime formed in freezing fog above 3300 feet.

Low clouds held tough through much of the day.

Clouds finally broke up for some late afternoon sunshine following more flurries, rime, and a nasty cold day that found temperatures struggling to reach 20 degrees at the top of the high country and 30 degrees in Norton-Wise.

A gorgeous, albeit cold, sunset graced the mountains.

Forecast models continue to struggle to resolve the track and precipitation amounts associated with a southward tracking clipper-like system which begins to spread moisture across the mountains by Thursday PM.

The forecast on this system is more difficult than usual since it remains disorganized and will not be in position to really intensify until it reaches the Atlantic Coast, with SE Virginia and the Tidewater around Richmond looking to be amid the main snowfall target zone by late Thursday Night into Friday morning.

The amount of snowfall observed locally this afternoon into Friday morning will be dependent upon moisture and wind direction, which will influence the temperature profile amid lower levels of the atmosphere ( air will be cold enough for all snow across upper elevations with only the amount there being unknown ).  The forecast may need to be updated later today as development of this system is followed over time.

Longer Term Peek

Conditions will remain chilly into this weekend with another weak system passing during Saturday.  This will keep relatively chilly temperatures in place with the real surge of warmth not coming until Monday into Tuesday as Atlantic ridging and western-central USA troughing develops.

A pattern opposite to that recently observed will develop next week with troughing to the west and ridging along-just off the East Coast of the USA.  This is a spring thunderstorm pattern, which will need to be closely followed over time.

Eventually, next week, a large upper trough will set up a return flow from the Gulf of Mexico and increase the potential for showers & thunderstorms.

A major outbreak of severe thunderstorms may develop west of the mountains, along with an excessive rainfall potential.

Have a great Thursday.

My Forecast For Today ( March 2 )

ALERT For A Sharp Overnight Temperature Drop With Developing Flurries & Snow Showers – Be Cautious Of Cold Wind Chills & Patches of Black Ice-Slickness

A significant overnight temperature drop will occur amid gusty NW winds behind the passage of an evening cold front.  Flurries and mostly light snow showers will develop along the upslope side of the mountains, with a dusting up to 1″ being possible ( greatest amounts at highest elevations ).  Use caution for the possibility of black ice or locally slick conditions into this morning.

Overnight Into Mid-Morning

Turning much colder.  Flurries & snow showers developing along the upslope side of the mountains with respect to NW winds.  Temperatures plunging into the 20s ( low-mid 20s in Norton-Wise ), with low-mid 10s at highest elevations in the High Knob Massif ( milder southward toward the Tri-Cities ).  Wind chills plunging into single digits & 10s ( locally lower in gusts atop the High Knob Massif ) overnight into the AM.  Rime formation in upper elevations above 3400 feet.

Mid-Morning Through This Afternoon

Flurries ending.  Skies becoming partly cloudy late.  Cold & blustery.  Winds WNW to NW at 5-15 mph with higher gusts.  Temperatures varying in the 30s at low-middle elevations to around 20 degrees at highest elevations in the High Knob Massif ( upper 20s-low 30s in Norton-Wise ).  Wind chills in the 10s & 20s on exposed mid-upper elevation ridges, except single digits in gusts at high elevations.

Tonight Into Thursday Morning

Partly-mostly clear evening skies giving way to increasing clouds into morning.  Light SSE-SSW winds at generally less than 10 mph on mountain ridges below 2700 feet.  Winds SSW-WSW at 5-15 mph on upper elevation ridges.  Temps varying from the upper 10s to the upper 20s, with readings tending to rise into morning, especially at high elevations.

An Alert For Accumulating Snow will likely be needed for the Thursday Night-Friday Morning period at mid-upper elevations, especially at elevations above 2500-3000 feet.

Weather Discussion ( March 1-2 )

My Early Afternoon Update

My update this afternoon is to cut temperatures even more than I had already ( I was already the coldest forecast out ), with low clouds being slow to clear.

It will become partly cloudy, but MAX temperatures are going to struggle to reach late PM maximums before the sun sets.  Temps at highest elevations will tend to rise overnight into Thursday AM as I already had in the forecast.

Observe extensive rime across the High Knob Massif where enough snow fell to cover roads at the highest elevations.  A dusting was also observed in Clintwood, in the valley, with around 0.2″ .

Temperatures at 1:30 to 2:00 PM varied from 29 degrees in Clintwood to 18 degrees atop the High Knob Massif, with 24 to 25 degrees in Norton-Wise ( the 27 at LNP is wrong ).

My friends Wayne & Genevie Riner submit this interesting photograph showing how the light morning snow created an amazing pattern on a very old Millstone.

Wayne Riner Thoughts On Photograph
Millstone With Snow: In my collection of rocks is an old millstone that was cut by hand many years ago. A light dusting of snow highlights the pattern of twelve grooves.

As of 1:30 PM, below, skies can be seen clearing northwest of the mountains across the Bluegrass and western foothills of Kentucky.

The 2:00 PM image, below, for comparison.  A slow but sure erosion of the low cloud deck from northwest to southeast.

Cloud bases have just lifted to reveal the summit level of the High Knob Massif, a blaze of rime and beauty on trees.

My Overnight Discussion

The month of March 2016 came ROARING into the mountains today and tonight, literally, with strong winds ahead-along a squall line and a cold front.  A wind advisory was needed but not issued officially.

This caused local wind damage as winds became severe in gusts along both the squall line and evening cold front.

While the Flatwoods Mountain Mesonet site adjacent to Pine Mountain takes honors for the highest recorded wind gusts, along the squall line ( above ) and cold front ( below ), it was only one place of many that had these ROARING winds.

We are fortunate to have these mountain ridge observation sites, and I wish there were more on the Virginia side of the border like at the windiest places ( e.g., High Knob Lookout – Pine Mountain ) and in mountain wave zones like Powell Valley.

The Black Mountain Mesonet site recorded a 49 MPH gust with the cold frontal passage at 8:10 PM.

The strongest wind here in Clintwood, which sounded like it might lift off the roof, occurred with the cold frontal squall that passed during the evening ( although the squall line at around 5:00 PM was no slacker ).

A peak gust to 39 mph was reported at Lonesome Pine Airport in Wise, but I do wonder if ( like the temperature ) this might not be reading accurately.  Perhaps we can get a station set up at UVA-Wise to have a check on these reports before next winter rolls around.

Focus now shifts to a blast of cold air, with 12:30 AM temps from the Kentucky Mesonet showing it certainly is coming.  The lower temperatures on the VA-KY border, with 28.9 on Black Mountain and 31.5 on Flatwoods Mountain, are due to elevation ( it is 28 degrees on Eagle Knob of High Knob ).

The coldest air will not arrive until the sunrise to mid-morning period today, with the 850 MB thermal min, and enough Great Lake moisture to kick off flurries and snow showers along the upslope side of the mountains on NW winds.

ROARING SW winds shifted W and now NW in direction as this system passed across the region.  The Flow across Lake Michigan picking up a little moisture as it bends into the mountains.

A Lake Michigan moisture plume will just brush the area with enough moisture for a dusting up to 1″ of snow into this morning ( most places likely having 0.5″ or less ).

Moisture advection being best northeast of this area into central-northern highlands of eastern West Virginia.

Any wetness on decks-porches-walks and other surfaces could cause slick and icy conditions, so please use caution if going outside overnight into this morning as temperatures drop below freezing.  Any snow burst or persistent snow showers could, of course, also cause some slickness.

It appears likely that an ALERT for accumulating snow will be needed by late Thursday into Friday morning.  This will be another elevation biased snow event, with indications for several inches or more at upper elevations above 3000 feet ( the lower limit of the accumulating snow will need figuring out as time gets closer, with places above 2000 to 2500 feet being initially targeted for 2″ or more.

Stay tuned for updates.

Stay Warm On This COLD Wednesday!

My Forecast For Today ( March 1 )

Update At 3:50 PM:  A Squall Line With A History Of Wind Damage Is Moving Across Eastern Kentucky Toward The VA-KY Stateline.  Expected Arrival Is Around 5:00-5:30 PM ( give or take 15 minutes ).

The squall line will reach Cumberland Gap by around 4:15 to 4:30 PM and the Norton-Wise area between 5:00 & 5:30 PM.

Previous Overnight Forecast

ALERT For A Dramatic Weather Change From Late This Afternoon Into Wednesday Morning.  A Squall Line Of Heavy Rain-Possible Storms Will Give Way To A Wind Shift With ROARING Evening Winds And A Sharp Drop In Temperatures Between 10 PM and Wednesday AM. Lingering Rain Changing To Snow ( A Dusting Up To 2″ Possible On Upslope Side of Mountains – NW Flow ).

*A large change in air pressure will drive a strong cold front across the mountains by late today into Wednesday AM.  A squall line of heavy rain-possible thunderstorms will reach the VA-KY stateline by around 5:00 PM, followed by ROARING evening winds as colder air begins to pour into the mountains.  Lingering rain showers will change to snow showers, with potential for light accumulations and icy-hazardous conditions ( underfoot and on some roads ) to form between 10 PM Tuesday and sunrise Wednesday.  Although snowfall amounts will be light, the sharp temperature drop could form black ice and eventually allow snow showers to stick at the higher elevations ( especially ).  Porches-decks-walks, etc…should be checked before stepping out onto them by Wednesday AM.

Overnight Into Tuesday Morning

Mostly clear.  Large vertical temperature spread forming between colder valleys and milder middle-upper elevation mountain ridges-plateaus.  Winds SSE-SW at 5-15 mph, with higher gusts, on mid-upper elevation ridges.  Temperatures varying from 20s in colder valleys to upper 30s to mid 40s on exposed mountain ridges and plateaus.  Wind chills in the 30s to lower 40s on mountain ridges.

Mid-Morning Through Late Afternoon

Increasing clouds.  Becoming windy.  A chance for showers by early afternoon.  A squall line of heavy rain & possible thunderstorms by late ( around 5 PM give or take an hour ).  SSW-SW winds increasing to 15-25 mph, with higher gusts, especially gusty on mid-upper elevation mountain ridges & plateaus.  Temperatures varying from the 40s to around 50 degrees at highest elevations in the High Knob Massif to the lower-middle 60s in milder locations.

*Although the risk for severe thunderstorms will be locally low, a very dynamic weather system and strong cold front will create an environment where this will need to be closely followed as one or more bands ( or a main squall line ) of showers-thunderstorms will be approaching the mountains from the west & southwest by late afternoon into this evening.  Damaging winds are the greatest threat, outside of always dangerous lightning, along with downpours of heavy rainfall upon an already wet ground. 

Late Afternoon Into Wednesday Morning

Showers & thunderstorms.  Locally heavy rainfall.  Some storms may be strong with a possible squall line timed to reach the VA-KY stateline by 5 PM ( give or take 1-Hour ).  Winds shifting WNW-NW at 10-20 mph, with gusts of 30-  40+ mph along and behind the cold front.  Turning much colder with a sharp temperature plunge from around 10:00 PM into the overnight period.  Rain showers changing to snow showers.  Temperatures plunging into the low-mid 20s by morning, with low-mid 10s at highest elevations in the High Knob Massif ( milder south toward the Tri-Cities ).  Wind chills plunging into single digits & 10s ( locally lower in gusts atop the High Knob Massif ) overnight into the AM.

A wet snow potential, with several inches possible, continues to be watched for the late Thursday into Friday AM period ( March 3-4 ).  Stay tuned for updates.

Weather Discussion ( Feb 29 – March 1 )

My Afternoon Update

The focus this afternoon is on a squall line of strong-severe thunderstorms, with a history of wind damage, moving into the Kentucky foothills near the mountains.

Some loud thunder & lightning in Clintwood at 5:11 PM

A 61 mph wind gust reported on Flatwoods Mountain, adjacent to Pine Mountain, near the Virginia-Kentucky stateline at 5:15 PM.

Blinding rain and strong winds in Clintwood at 5:22 PM

It has gotten dark like night with heavy rain and wind at 5:25 PM in Clintwood ( now into Norton-Wise ).  Booming thunder with a lightning strike at 5:29 PM.

Another BOOM of thunder with vivid lightning at 5:32 PM.

The line is weakening across the High Knob Massif area.

Wind damage has occurred in London, Ky., including buildings, trees, and at least 1 injury, with passage of this squall line.

Warnings have expired in eastern Kentucky, currently, but the line continues to have a mini-waves indicative of strong winds.

This warning is no longer in effect.

Temperatures remain chilly atop the high mountains this afternoon with middle 40s.  This means limited instability with dewpoints in mid 40s to lower 50s across the area.

However, momentum transfer of strong winds aloft will remain possible.  ROARING winds will overspread the area tonight behind the cold front.

My Overnight Discussion

A simply lovely close to the month of February, and also Meteorological Winter, has given way to a cold and frosty night amid mountain valleys verses gusty conditions and “milder” temperatures atop mid-upper elevation ridges.

It was 30.0 degrees exactly at my official Clintwood station at Midnight, with 31 degrees in Jonesville and Sandlick, verses a relatively balmy ( by contrast ) 46 degrees ( really 44 with the warm bias ) at Lonesome Pine Airport in Wise.

Colder mountain valleys were already in the 20s at Midnight, such that this large vertical temperature spread will increase into the overnight between valleys that remain decoupled ( detached from winds above ) from the flow field of the atmosphere and breezy-gusty mountain ridges & plateaus.

The main focus of this forecast period is on a dramatic weather change that will be developing between late this afternoon and Wednesday morning, with high-resolution models of the NAM group now coming into line with the more aggressive forecast of the European Model.

Note too the 58+ mph low-level jet being shown along the front where  isobars bend into a trough above over SE Kentucky.  While winds will be gusty before the front, all locations will tend to develop ROARING winds into evening as much of that momentum mixes downward toward the surface along with increasing cross-barrier flow as barometric pressure begins adjusting across the Appalachian chain ( large pressure falls then rises tonight ) from northwest to southeast.  A classic strong wind setting for a time later today into tonight.  Any squall line with heavy rain will be amid this setting ( toward 5:00 PM, give or take an hour ).  A squall line also implying that the heavy rain will tend to be limited in time ( good news for wet ground, yet downpours must always be respected in case they might linger over any given place for a little longer in time ).

To illustrate the change, the NAM Model predicts the 7:00 PM temp over Wise to be 48 degrees up at the summit level of the High Knob Massif.  By 7:00 AM Wednesday ( below ) the air temperatures has plunged to 12 degrees at the High Knob summit ( a 36 degree drop which can be translated downward to Norton-Wise to mean temps that plunge from 50s to around 60 degrees this afternoon to 20-23 degrees by Wednesday morning ).  This temperature drop is also forecast by the European Model ( increasing confidence ).

Winds continue to be gusty, especially along mid-upper elevation ridges-plateaus, into Wednesday morning such that feels-like conditions will truly be dramatic relative to temperatures experienced for a time today.

Any time there is such a dramatic air mass change the risk for strong to locally severe thunderstorms often must be respected ( especially entering Meteorological Spring ).

The Cumberland Mountains remain on the fringe with a marginal risk being maintained for severe storms.  The greatest severe threats ( as I had already noted earlier ) being for the possibility of damaging winds.

Kentucky is at the center of the potential for at least brief spin-ups ( tornadoes ) today, west of the mountains, and it will be this activity that will need watching as it pushes eastward to the mountains during the afternoon.

The 1:00 AM run of the HRRR Model has the squall line getting close to the Virginia-Kentucky border, west of Cumberland Gap, around 4:00 PM.  So I have adjusted my timing for Norton-Wise upward to 5:00 PM ( give or take an hour ).  This timing may still change and have to be updated later.

Stay tuned to NOAA Weather Radio for possible watches and/or warnings that might be needed today.

Have a great Tuesday.

My Forecast For Today ( February 29 )

ALERT For Strong SW Winds Tonight Into Monday Morning Is In Effect For The Cumberland Mountains

SW winds will continue to roar across the mountain area in advance of a cold front with rain showers.  The strongest winds will occur at mid-upper elevations, above 2000 feet, and with mountain waves northeast of the High Knob Massif and Black Mountain into portions of the Russell Fork basin.

A Risk For Strong-Severe Thunderstorms Will Become Possible By Late Tuesday, Especially West-Southwest Of The Cumberland Mountains.

Overnight Into This Morning

Increasing clouds with showers developing by the predawn to sunrise period.  Windy.  SW winds 15-30 mph, with gusts of 35-40+ mph.  Temperatures varying from low-mid 40s at highest elevations in the High Knob Massif to widespread readings in the 50s, then dropping around sunrise into mid morning with onset of showers.  Wind chills in the 30s and 40s on exposed mid-upper elevation ridges-plateaus.

Mid-Morning Through Monday Afternoon

Decreasing clouds with mostly sunny conditions developing into afternoon.  Winds becoming WNW-WSW & decreasing to 5-10 mph.  Mid-morning temperatures in the 30s and 40s rising into the low-mid 40s to low-mid 50s ( coolest at the highest elevations & milder south toward the Tri-Cities ).

Tonight Into Tuesday Morning

Mostly clear.  Large vertical temperature spread forming between colder valleys and milder mid-upper elevation mountain ridges-plateaus.  Winds SSE-SSW at 5-15 mph, with higher gusts, on mid-upper elevation ridges.  Temps varying from 20s in colder valleys to the upper 30s to mid 40s on exposed mountain ridges-plateaus.  Wind chills in the 30s to lower 40s.

While rain may change to snow showers at mid-upper elevations into Wednesday morning ( any accumulations are currently most likely at highest elevations ), a more important storm system will present a wintry potential Thursday Into Friday ( March 3-4 ).  Please stay tuned for updates on both of these systems.

Weather Discussion ( February 27-29 )

My Afternoon Update

Following morning showers, clouds, and a dip into the 30s and 40s this afternoon has been ideal with beautiful blue skies and decreasing winds.

Afternoon temperatures varying from chilly 40s atop the High Knob Massif to the mid-upper 50s in Norton-Wise and adjacent plateau-ridge communities.

The main focus of this update being on the latest Day 2 outlook from the Storm Prediction Center where, as I had expected, there have been some modifications.

This will be a very dynamic system and could again feature a setting that goes from heavy rain, with thunder, to snow as temperatures plunge behind the cold front.  Any sticking snow of importance continues to look like it will be within upper elevations around or above 3000 to 3500 feet ( even there it will be light if cold air does not catch up to the back side of the main moisture field ).  I will update that tonight.

As is typically the case here in the mountains at this time of year, marginal dewpoints & low-level instability are limiting factors for severe thunderstorms verses much better ( stronger ) dynamics.  Strong-severe thunderstorms can not be ruled out, but the latest marginal risk does look ( currently ) to be most appropriate. 

There will be a band, or bands, of heavy rain with embedded thunderstorms along & ahead of the strong cold front, with models trying to figure out where it will be.  The latest run of the European Model places the main band right over the Virginia-Kentucky border counties.  This will also need updating later tonight.

My Overnight Discussion

Reference February 2016 Majesty In High Knob Massif for a set of photographs and information detailing this recent winter storm.

The main weather focus Sunday evening into this early overnight period of Monday is ROARING winds, which I have put an alert out for and noted back on Friday Night.

SW wind gusts of 30 to 50 mph have been common across the area this evening into the overnight.  ROARING winds.

Wind speeds began increasing at upper elevations during early afternoon, with downward mixing and lowering of strong and gusty winds into the evening.

Sunday afternoon temperatures varied widely from the 40s over lingering snow on northern slopes in upper elevations of the High Knob Massif ( with colder wind chills ) to a mild 64 degrees on downsloping winds at Clintwood 1 W.

Temperatures reached mid-upper 50s in the Norton-Wise area.

The timing and pulsating nature of ROARING winds at Clintwood 1 W are characteristic of past SW flow events that have produced mountain waves NNE-NE of the High Knob Massif and Tennessee Valley Divide.

It if were daytime these waves would show up much better with increasing moisture.  Tonight there is only visual indications of their presence on infrared satellite imagery.  NNE-NE of the High Knob Massif-Black Mountain corridor, in particular, is a locally known and well documented past generation zone for waves which occasionally do reach into lower elevations.

*Other indicators of these waves are relatively light winds in places like Jonesville & Duffield verses Pound-Clintwood during the same time, with downward mixing of strong and ROARING winds into Pound-Clintwood.

All this atmospheric energy will dissipate quickly following a line of showers along a cold front which arrives into the predawn-sunrise period, with a wind shift and decreasing speeds as skies become mostly sunny into this afternoon.

Until then, batten down the hatches!

This remains a very active pattern so the lull will be brief.

A more important storm system and cold front will ramp winds back up across the mountains late Tuesday into the Tuesday Night-Wednesday Morning period as a band of rain, with possible thunder, moves into the area.

A 200+ knot jet streak will be moving across the region during Tuesday Night into Wednesday Morning.  There will be significant speed shear, and enough directional shear, for mesocyclonic cells to develop along and in advance of the cold front and a lobe of energy ( 500 MB vorticity ) in mid-levels of the atmosphere.

Observe how the synoptic-scale spin ( below ) shows up well in the atmosphere.  The alignment of upper dynamics, with the left front exit region of this potent 200+ knot jet streak & differential positive vorticity advection associated with this mid-level energy, will be important as to how the risk for severe thunderstorms unfolds.  Stay tuned for updates.

The Storm Prediction Center has already placed the area within a large slight risk region for severe thunderstorms, with later modifications being possible to likely.

The precise evolution of the convection remains uncertain but powerful upper level dynamics ( as I noted above via a few of numerous ingredients ) mandates that this situation be closely following as the main risk of any severe storms develops locally by Tuesday Night.

Have a great Monday.

My Weekend Forecast ( Feb 27-28 )

ALERT For Strong SW Winds Tonight Into Monday Morning Is In Effect For The Cumberland Mountains

Reference my 022616 Forecast for details on current conditions.

Saturday Forecast

A period of partly to mostly clear evening skies Friday will give way to mostly cloudy conditions overnight into the sunrise to mid-morning period on Saturday ( a few more flurries can not be ruled out, especially in upslope sites ).

Expect light valley winds and W-WNW winds of 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges & exposed plateaus.  Temperatures will vary from teens to mid-upper 20s across most of the area.

Clouds begin breaking up for a longer time period during the morning, with partly to mostly sunny afternoon skies expected to give way to a cold and mostly clear night.

Expect Saturday afternoon temperatures to vary from 30 to 35 degrees over snow along high crest lines and north slope locations in the High Knob Massif to the lower-middle 40s, with a little milder conditions lee of the mountains toward river valleys of the Clinch, Powell, Holston and Tri-Cities.

Saturday night will feature an increasing vertical temp spread between mountain ridges and valleys, with SW to WSW winds of 10-20 mph, and higher gusts, along mid to upper elevation mountain ridges & exposed plateaus.

This will cause temperatures to tend to rise at the highest elevations from late Saturday Night into Sunday Morning.  In contrast, valleys with light-calm winds will drop such that temperature spreads will vary from 10s to low 20s in colder valleys to 30s along exposed mountain ridges.

An ALERT for strong & gusty winds may be needed for middle to upper elevations by late Sunday into Sunday Night as the pressure gradient tightens along the Cumberland Mountains in advance of the next weather system.

Sunday Forecast

The day begins with mostly clear skies and a relatively large temperature spread between valleys sheltered from gusty SW-WSW winds and exposed locations & mountain ridges.  Although deep valleys will have colder air temps, wind chills along high ridges will make it feel just as cold.

Mostly sunny skies are currently expected with a large temp spread between upper and lower elevations.  A bias toward a little cooler valley conditions will also exist for locations along and southwest of the High Knob Massif & Tennessee Valley Divide, where rising air will hold PM temperatures lower than with sinking on SW flow into lower elevations across the Russell Fork & Levisa Fork basins.

Specifically, afternoon temperatures will vary from the lower-middle 40s over snow cover at upper elevations & northern slopes in the High Knob Massif to the middle-upper 50s ( 60+ may occur in some downslope locales ).  Actual “feels-like” conditions will be more extreme with wind chills making the afternoon feel like 20s to mid 30s for those who might dare to visit the High Knob Lookout.

Late Sunday into early Monday will feature increasing winds & clouds with a chance for developing rain showers.  SW-WSW winds of 20-40+ mph will become possible across middle-upper elevation mountain ridges & plateaus.

Weather Discussion ( February 26+ )

Some late PM brightening of cold, cloudy conditions helped to illuminate widespread snow cover across the High Knob Massif, and set the stage for a beautiful and colorful sunset.

This was a day featuring prolific mountain waves on NW flow, with NASA visible imagery offering some nice views.

There is little doubt where the true mountains begin, with waves popping out from the Cumberland Mountain Overthrust Block and Pine Mountain southeastwards.

Some instability became superimposed on the NW flow into the afternoon, with “bumpy” clouds over much of Scott County along and lee of the High Knob Massif amid turbulent flow.

Looking ahead, a volatile pattern will open the first week of March with up-down temperature swings and more periods featuring strong winds, rain, and snow.

As I have already highlighted, the time with gushing whitewater draining from the High Knob Massif is a testimony to winter storminess already experienced.

This latest storm system pushing total precipitation into the 25.00″ to 30.00″ range for upper elevations in the High Knob Massif since December 1.

Reference Winter Majesty In High Knob Massif for totals measured before this latest major storm dropped an additional 2.50″ to 3.00″ of precipitation on the massif area ( 2.44″ being measured on the northern base of the massif at the City of Norton Water Plant ).

As highlighted in my 022016 Extended Outlook, the big picture will feature a prolonged negative trend to the  Arctic Oscillation coupled with a positive Pacific North American oscillation.

This will maintain a general western USA ridge and eastern USA trough pattern in the mean, with tendency for colder than average conditions ( in the mean ).  Radical up-down temperature swings will also remain likely in early days during March ( with perhaps a more stable cold pattern arising later…still too early to tell about the stability ).

While the mean western USA ridge & eastern USA trough pattern is very clearly seen on the MEAN of the 51-Member European Ensembles, there is a potential for an Omega type of blocking setting toward DAYS 7-10 ( featuring ridging centered more on the Rockies-western Plains ).

To be honest, the upcoming pattern will be complex and greatly complicated by waves in the Polar and Sub-tropical Jet Streams that will at times have the potential to phase.  Any phasing could alter the upper air configuration and skew it away from the MEAN shown.

Initial focus this coming week will be on a couple of potentially major storm systems.  The first one of note arises by Tuesday-Wednesday ( March 1-2 above ).

The next potential storm ( below ) will also be a concern with Gulf of Mexico moisture connection yet again.

Tracks and intensities on these remain to be determined, but clearly the stage is being set via the upper pattern and embedded waves in the Polar & Sub-tropical Jets for more storminess in coming days.  These will be the focus of future forecasts, so stay tuned for updates.

Have a great Weekend.

My Forecast For Today ( February 26 )

ALERT For Accumulating Snow Overnight Into This Morning Along The Upslope Side Of The Mountains.  Caution For Hazardous Road Conditions Along and North of High Knob Massif-Tennessee Valley Divide.

A period of increased low-level moisture will develop overnight with snow showers and local squalls increasing along the upslope side of the mountains ( with respect to NW winds ).  At 11:00 PM a burst of snow had moved through Breaks Interstate Park.

Additional new accumulations of 0.5″ to 2″ are expected at lower and middle elevations, with 2″ to 3″ within upper elevations of the High Knob Massif.  Little to no accumulation, as has been expected, will occur along the downslope side of the mountains ( this ALERT has always been posted for the upslope side of the mountains with respect to NW winds ).

Overnight Into Mid-Morning Friday

Snow showers & flurries.  Snow may be heavy at times in the overnight-sunrise period.  W to NW winds 10-20 mph, with higher gusts.  Temperatures varying from the low-mid 10s at highest elevations to the mid-upper 20s  ( milder at lower elevations toward the Tri-Cities ).  Wind chill factors varying from single digits below & above zero at the upper elevations to the 10s to lower 20s.  Blowing snow, with additional rime formation, at highest elevations.

Mid-Morning Through This Afternoon

Mostly cloudy & cold.  Chance of flurries or snow showers.  W-NW winds 5-15 mph, with higher gusts.  Temperatures varying from lower 20s to lower-mid 30s ( coldest at the highest elevations ).  Wind chills in the 10s & 20s, except some single digits at highest elevations.

Tonight Into Saturday Morning

Mostly cloudy & cold.  Chance of flurries.  W-WSW winds at 5-15 mph, with higher gusts, along mid to upper elevation mountain ridges.  Temperatures mostly in the 20s, varying from around 20 degrees at highest elevation to around 30 degrees.  Wind chills in the 10s & 20s, except some single digits along upper elevation mountain ridges.

Weather Discussion ( February 25-26 )

My Afternoon Discussion

Its been a cold day across the mountain area with 4:00 PM temperatures varying from a bitter 20 degrees atop Eagle Knob of the High Knob Massif to 31 degrees ( 30.6 ) at the City of Norton Water Plant ( reported by Joe Carter ).

This followed an overnight that featured periods of heavy snow from the High Knob Massif northward into parts of Wise and Dickenson counties.

A general 0.5″ to 2.0″+ of new snow accumulated, enough to force Wise County to close schools on this TGIF ( Feb 26 ).  No new snow accumulated in many downslope places, as well as in spots that happened to miss the overnight snowstreaks and squalls along upslope sides of the mountains ( e.g., only a trace in Grundy ).

Total snowfall during this event had reached 4.0″ in the High Chaparral community of the High Knob Massif up to 9:43 AM this morning.  Look for scenes from the summit level and main crest zone coming later.

Snowfall was generally less in Norton-Wise and less still toward Pound and Clintwood where, with melting Thursday, some places barely had a dusting ( that missed overnight snow squalls ).

In general; however, it was clearly an elevation biased snow event featuring snowfall ranges along the upslope side of the mountains which varied from 1″ to 6″+ ( during the entire Feb 24-26 period ).

My Overnight Discussion

Light snow has been increasing, mixed with sleet in valleys, over Dickenson and Buchanan counties during the evening with a burst of heavier snow recently moving through the Breaks Interstate Park area.  This marks the beginning of a return of better low-level moisture.

When forecasting Great Lake connected NW upslope flow, from this far away from the moisture source, it is all about being PATIENT and giving the moisture time to make the long trek downstream into the mountains.

Nothing had changed dramatically in the flow, as was expected, with a mostly mid-continental flow into the mountain area at 7:00 PM.  That supported light snow.

Overnight models continue to show the flow shifting to off Lake Michigan into the mountains for a period of time from the overnight-predawn into mid-morning Friday.  This will be the period for accumulating snow ( i.e., Midnight to Mid-Morning on Friday will be the best time ).

The only change in my forecast has been to reduce snowfall amounts slightly due to sleet mixing in at lower elevations this evening within the Russell For Basin.

With Great Lake supported upslope flow upstream radars may not look very active, but echoes increase along the mountains as moisture reaches the lifting zone.

Streamers are clearly visible coming off Lake Michigan, indicating that moisture is being transported off the open Lake.  Little is seen beyond the immediate inland Lake zone in Michigan-Indiana until the air reaches the Appalachian foothills in Kentucky & western West Virginia ( with additional lifting then into the Alleghenies and Cumberland mountains ).

One reason I have not backed off on overnight snowfall is that there is also to be a 10 degree temperature drop at the summit level of the High Knob Massif, and in many places, with arrival of the 850 MB thermal MIN and coldest air that will help promote increased dendritic crystal growth at a lower altitude in the atmosphere ( even though the most prime growth zone of -12 to -17 C is not quite going to be reached there should still be some decent crystal growth ).

So time will tell.  One of the problems in dealing with Great Lake moisture is that only a few degrees of change on the compass can make for large changes downstream at distances of 400 air miles, and models have a difficult time resolving these streams of richer low-level moisture with respect to where they will exactly form and reach over time.

*The distance from the end of Lake Michigan to the High Knob Massif is approximately 400 air miles.

Whitewater continues to gush as part of a prolonged period with significant flow on the dozens of steep creeks draining the High Knob Massif ( a testimony to February and Winter wetness in this 2015-16 season ).

Have a great TGIF.