*Frost Formation Will Be Possible Into Sunday Morning In Colder Mountain Valleys, Especially At Elevations Above 2500-3000 feet.
Fog Formation Will Be Possible In Other Locations At Low-Middle Elevations In the Clinch, Powell, Russell Fork-Levisa Fork, Holston and Cumberland River basins.
Overnight Into Saturday Morning
Mostly cloudy and turning cooler. Winds NW-NNE at 5-15 mph, with higher gusts. Temperatures dropping into the lower 40s to lower 50s ( coolest at the highest elevations ). Wind chills in the 30s along upper elevation ridges.
Saturday Afternoon
Decreasing clouds by mid to late afternoon into the early evening. Cool. NNW-NNE winds at 5-15 mph, with higher gusts. Temperatures varying from upper 40s-lower 50s at highest elevations in the High Knob Massif to the lower to middle 60s ( milder south toward the Tri-Cities ).
Partly cloudy skies will continue along and south-southwest of the High Knob Massif into this evening, with mostly cloudy skies along and north-northeast of the massif. Highest elevations will remain obscured in orographic clouds ( i.e., dense fog ).
Saturday Night Into Sunday Morning
Becoming mostly clear. Seasonably cold. Frost possible in high valleys with fog formation in many other locations. Winds light and variable. Temperatures varying from the upper 20s & 30s in colder valleys ( 28-34 in coldest valleys above 2500 feet ) to the middle-upper 40s.
Sunday Afternoon
Mostly sunny. Warmer. Winds becoming SSW to SW at generally less than 10 mph. Temperatures varying from 60s at highest elevations to the mid-upper 70s.
Sunday Night Into Monday Morning
Partly to mostly clear. Milder. Winds SSW-SW at 5-15 mph on middle elevation ridges & plateaus below 2700 feet. SW-WSW winds 10-20 mph, with higher gusts, along mountain ridges above 2700 feet. Temperatures varying from mid 30s to lower 40s in colder mountain valleys to the 50s on middle to upper elevation mountain ridges-plateaus.
Monday Afternoon
Partly to mostly sunny ( high clouds ). Warm. SSW-SW winds 5-15 mph, with higher gusts. Temperatures varying from mid 60s to lower 70s in upper elevations to the lower to middle 80s ( warmest at lower elevations of the Russell & Levisa Fork basins ).
Monday Night Into Tuesday Morning
Partly to mostly clear. Winds SSW-SW 5-15 mph, with higher gusts, along middle elevation ridges-plateaus at elevations below 2700 feet. Winds SW-WSW 10-20 mph, with higher gusts, along mountain ridges above 2700 ft. Mild with temperatures varying from the 50s to lower 60s on exposed mountain ridges-plateaus to the 40s to lower 50s within mountain valleys.
Showers & thunderstorms will become likely by late Tuesday into Wednesday & Thursday. Locally heavy rainfall and strong-severe thunderstorms will become possible, especially west and north of the mountains ( however, this will need to be closely followed ). Please stay tuned for updates.
Weather Discussion ( April 22-24 )
Saturday Afternoon Update
A large difference in conditions has been observed today, with partly cloudy skies south-southwest of the High Knob Massif-Black Mountain area verses low clouds along and to the north-northeast of this high terrain. Highest elevations have remained obscured in dense fog of orographic clouds.
High Knob Massif Webcam – University Of Virginia’s College At Wise
Cloud bases are higher, and skies are brightening at times, with drier air upstream of the mountains moving south.
NASA Visible Satellite Image At 8:30 AM Saturday – April 23, 2016
Differences between this morning and this afternoon can be seen on NASA visible imagery, with increasing dry air along and north to northwest of the mountains on northerly air flow.
Observe the same pattern, with lee-side cloud breaks, has been present all day for many places across Scott, Lee and adjoining counties resting along and downstream of the windward slopes of the High Knob Massif & Black Mountain. This has been in contrast to a persistent low cloud deck along and north of the High Knob Massif & Tennessee Valley Divide.
NASA Visible Satellite Image At 3:30 PM Saturday – April 23, 2016
Temperatures in the 40s to middle 50s have been felt all day along and north of the High Knob Massif verses 60s to near 70 degrees in the Great Valley of eastern Tennessee and in lower sections of the Powell River Basin toward Cumberland Gap.
NASA Visible Image With TEMPS Overlaid At 3:30 PM – April 23, 2016
No real changes in my previous forecast other than to stress these differences more for the remainder of this afternoon into early evening until drier air overspreads the area.
One change for tonight is to increase the potential coverage of fog to include much of the area outside of places having valley floors above 2500-3000 feet where drier air will be favorable for frost formation.
My Previous Discussion
Much needed, welcomed showers and local downpours in thunderstorms soaked the mountain landscape during the Thursday Night-Friday period of April 21-22.
Spring Moisture On The Trail of The Lonesome Pine – Powell Valley ( April 22 )
Some of the heaviest rain fell over the High Knob Massif with general 1.00″ to 1.50″+ amounts. The greatest rain gauge tally reached 1.69″ at the Upper Norton Reservoir.
Looking South To South Fork of Powell River Gorge – April 22, 2016
A seasonably cool to chilly air mass will be felt Saturday into Saturday Night-Sunday Morning, with abundant clouds that eventually give way to clearing via the advection, or transport, of much drier low-level air back into the area.
This will set the stage for frost formation into Sunday Morning in mountain valleys with drainage from upper elevations where the 850-875 MB dewpoints will be tanking overnight Saturday into the morning hours of Sunday. With light winds, and dry air, strong radiation cooling and development of cold air drainage flows will help fill mid-upper elevation valleys with cooling air.
A simply gorgeous, much warmer Sunday is on tap following the morning chill with large mountain valley temperature rises into the afternoon.
A more active pattern returns next week with rounds or waves of showers and thunderstorms expected. Some of these may become strong to locally severe if a NW flow pattern develops. Stay tuned for later updates.
ALERT For Anomalously Dry Conditions Continues Until Beneficial Rain Falls – Please DO NOT BURN
Overnight Into Thursday Morning
Partly to mostly cloudy ( mid-high clouds ). Winds SSE-SSW at 5-15 mph, with higher gusts, along mid elevation ridges and plateaus below 2700 feet. Winds SSW-SW at 10-20 mph, with higher gusts, along mountain ridges above 2700 feet. Temps varying from the 40s in cooler mountain valleys to the 50s to around 60 degrees on exposed middle to upper elevation mountain ridges & plateaus.
Thursday Afternoon
Partly to mostly cloudy. Windy & unseasonably warm. SSW winds 10-20 mph, with higher gusts. Temperatures varying from 60s in upper elevations to the 70s to low 80s ( warmest at lower elevations in the Russell Fork-Levisa Fork basins ).
Thursday Night Into Friday Morning
Mostly cloudy. Scattered showers with a chance for thunderstorms. SSW winds 5-15 mph, with higher gusts, below 2700 feet. Winds SW-WSW at 10-20 mph, with higher gusts, on mountain ridges above 2700 feet. Temperatures widespread in the 50s, varying from around 50 degrees at highest elevations to around 60 degrees warmest locales.
Friday Afternoon
Scattered showers & thunderstorms. Cooler. SSW to WSW winds 5-15 mph, with higher gusts ( especially on mountain ridges ). Temperatures varying from low-mid 50s in upper elevations to the upper 50s to middle 60s.
Friday Night Into Saturday Morning
A chance for showers & thunderstorms during the evening, then mostly cloudy ( decreasing clouds in the AM ). Turning cooler. Wind shifting NW-NNE at 5-15 mph. Temperatures dropping into the middle 40s to middle-upper 50s ( coolest at the highest elevations ).
Weather Discussion ( April 17-21 )
Unseasonably warm and dry conditions continue across the mountain area, with huge day-to-night temp spreads being observed ( and felt ) in mountain valleys.
*An update to Daily MAX-MIN temperatures recorded at the official National Weather Service station in Clintwood:
Official NWS Temperatures – Clintwood
( April 16 ) Saturday AM 33 degrees
Saturday PM 75 degrees
( April 17 ) Sunday AM 33.9 degrees
Sunday PM 80 degrees
( April 18 ) Monday AM 36 degrees
Monday PM 84.5 degrees
( April 19 ) Tuesday AM 40.0 degrees
Tuesday PM 81 degrees
( April 20 ) Wednesday AM 44.0 degrees
Wednesday PM 84.5 degrees
Changes are finally beginning to show up with the first chances for needed rainfall developing by later today into Friday morning in advance of an approaching cold front.
Rainfall amounts remain questionable given a long period of pre-conditioning with subsidence ( sinking air ) over the region at both upper and locally at lower levels ( with down-sloping on easterly-southerly air flow trajectories ).
NAM 12 KM Model Total Rainfall Forecast
The NAM Model is most aggressive, with higher rainfall totals than both the GFS and European models between now and Saturday AM.
NAM 4 KM Model Total Rainfall Forecast
A zoomed in look at the high-resolution NAM shows that the model is trying to display a hit-miss pattern of downpours, with typically large variations in amounts over relatively short distances ( as is the nature of convection ). If convection does not develop locally then rainfall amounts are likely to be much lower in all places.
*There is still time to turn around an anomalously dry Spring. However, this is important, the next 6 weeks through May will be very important as trees-vegetation green & evapotranspiration increases input of moisture into the lower atmosphere.
After the landscape greens, if dryness continues, then input of moisture into the lower atmosphere will become reduced and a feedback for the continuation of dryness will be favored. Positive & negative feedbacks between surfaces of the Earth and overlying atmosphere become major players in weather experienced during the convective season, on scales ranging from the synoptic to the meso ( local ).
GFS Model Total Rainfall Forecast
The main period for rainfall being approximately a 24-hour window of opportunity for possible beneficial amounts, from Thursday Evening through Friday Evening.
Following drying and another nice weekend, a more active pattern is looking possible next week with a strong baroclinic zone setting up from north to south across the eastern USA. Stay tuned as I will be updating this in coming days.
ALERT For Continued Anomalously Dry Conditions Into Thursday – Please DO NOT BURN Anything Until Beneficial Rain Falls
Overnight Into Tuesday Morning
Mostly clear. Large vertical temperature spread between colder valleys & mild mid-upper elevation ridges-plateaus. Light winds, except N-NW at 5-10 mph, with some higher gusts, along mountain ridges above 2700 feet. Temps from 30s to lower 40s colder valleys to the 50s to near 60 degrees on exposed mid-upper elevation mountain ridges-plateaus.
Tuesday Afternoon
High cloudiness. Unseasonably warm. NW-N winds at 5-15 mph, with higher gusts. Temperatures varying from 60s to around 70 degrees in upper elevations to the upper 70s to middle 80s ( warmest in lower elevations ).
Tuesday Night Into Wednesday Morning
High clouds. Large vertical temperature spread between colder valleys & mild mid-upper elevation ridges-plateaus. Winds becoming ESE-SSE at 5-15 mph along middle to upper elevation mountain ridges-plateaus. Temperatures varying from upper 30s to mid 40s in colder valleys to upper 50s to lower 60s on exposed mid-upper elevation ridges-plateaus.
Wednesday Afternoon
Partly to mostly cloudy ( mid-high clouds ). Unseasonably warm. SSE-S winds at 5-15 mph, with higher gusts. Temps varying from 60s in upper elevations to the mid 70s to low-mid 80s ( warmest in lower elevations of the Russell Fork and Levisa Fork basins ).
Wednesday Night Into Thursday Morning
Partly to mostly cloudy ( mid-high clouds ). Winds SSE-SSW at 5-15 mph, with higher gusts, along mid elevation ridges and plateaus below 2700 feet. Winds SSW-SW at 10-20 mph, with higher gusts, along mountain ridges above 2700 feet. Temps varying from the 40s in cooler mountain valleys to the 50s to around 60 degrees on exposed middle to upper elevation mountain ridges-plateaus.
Weather Discussion ( April 17-19 )
Unseasonably warm ( by day ) and dry weather pattern continues to dominate the mountain region, with HUGE temperature spreads between day-night being observed amid mountain valleys.
Official NWS Temperatures – Clintwood
( April 16 ) Saturday AM 33 degrees
Saturday PM 75 degrees
( April 17 ) Sunday AM 33.9 degrees
Sunday PM 80 degrees
( April 18 ) Monday AM 36 degrees
Monday PM 84.5 degrees
Widespread to patchy frost has been observed in these colder valleys during the past 3 nights, highlighted above, to contrast with much milder conditions 500-1000+ vertical feet higher.
A 48.5 degree temperature spread between Monday AM & PM is only one example of wild night-day temperature swings observed in mountain valleys during the past week.
I thank my friend Chris Allgyer, of the MECC Mathematics Department, for identifying this moth species that I captured on a cut log during Sunday. It was in a dark location, so I had to over-expose the photograph in order for it to stand out; otherwise, the picture could have been sharper with good light ( the brightness above being due to longer time exposure ).
It is enough to make even a moth’s eyes bug out. Folks living upon the middle-upper elevation ridges and plateaus, by contrast, have experienced lesser day to night temperature spreads with 60s-70s by day and 40s-50s by night.
Nora 4 SSE – NWS Site In Middle Elevations At 2650 feet
The Monday temperature spread on Long Ridge of Sandy Ridge, for example, at the official recording site of Wayne and Genevie Riner, varied from the upper 50s to the upper 70s ( only around 20 degrees instead of nearly 50 degrees ).
Large-flowered Trilliums ( Trillium grandiflorum ) – April 18, 2016
Only a few hundred vertical feet of elevation difference has been making a large difference in temperature, with well developed cold air drainage flows into hollows-valleys during recent nights with very efficient cooling in low dewpoint ( very dry ) air.
NAM 12 KM Model Total Rainfall Forecast Next 84-Hours
With such dry air it is going to be tough generating any significant rainfall to help with these dry conditions and forest fires burning across the region.
The latest European Model tonight is forecasting less than 0.50″ of rain to fall through this weekend. It is showing potential for some heavy rainfall during the 5-10 day forecast period, amid the final week of April as a frontal boundary wobbles about the region to the south of a strong baroclinic zone ( temperature gradient ).
Currently the best signs for soaking rain, with showers and downpours in thunderstorms, is looking to develop out in the extended forecast period ( the 5-10 day range ) during final days of April 2016.
Meanwhile, some rain will be possible during late week but it may again be in a “weakening” mode as it fights this very dry air mass set up over the region ( a deep vertical column driven by a subsidence regime adjacent to excessive rainfall over the lower Mississippi Valley ).
*More rain fell in just 24-hours in parts of the Houston, Tx., area than has been observed across most of this region all year. In fact, it was nearly double what has been measured in the Tri-Cities so far this year ( 9.81″ during January 1-April 19 verses more than 17.00″ in 24-hours amid wetter parts of the Houston Metro ).
Past climatology clearly shows a strong correlation to dryness in this region when excessive wetness sets up over the Mississippi Valley and southern-central Plains ( and vice-versa as wetness over this region is often correlated with dryness and drought across the former region ). This is no accident, and is part of a great atmospheric compensation regime of rising-sinking air.
Clear. A large vertical temperature spread between colder valleys and milder mid-upper elevation ridges & plateaus. Winds ESE to SE at 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges ( calm winds in valleys ). Temperatures varying from frosty upper 20s to mid 30s amid colder valleys to the upper 40s to middle 50s along exposed ridges and plateaus.
Sunday Afternoon
Sunny. Beautiful blue skies. Warm. Rapid temperature rises in valleys. Winds NE-ENE at generally less than 10 mph. Temperatures varying from 60-65 degrees at highest elevations to middle-upper 70s at lower elevations ( 70-75 degrees in Norton-Wise and the Sandy Ridge communities ).
Sunday Night Into Monday Morning
Clear. A large vertical temperature spread between colder valleys and milder mid-upper elevation ridges & plateaus. Light winds ( NE-N at generally less than 10 mph along ridges above 2700 feet ). Temperatures varying from 30s in colder mountain valleys, with a chance for frost, to the 50s along exposed mid-upper elevation ridges-plateaus.
Monday Afternoon
Sunny. Unseasonably warm. Rapid temperature rises in valleys. Light northerly winds. Temperatures varying from 60s in upper elevations ( above 3000 feet ) to 80-85 degrees in lower elevations ( below 2000 feet ). Mid-upper 70s are expected in Norton-Wise and Sandy Ridge communities.
Monday Night Into Tuesday Morning
Mostly clear. Large vertical temperature spread between colder valleys & mild mid-upper elevation ridges-plateaus. Light winds, except N-NW at 5-10 mph, with some higher gusts, along mountain ridges above 2700 feet. Temps from 30s to low 40s colder valleys to the 50s to near 60 degrees on exposed mid-upper elevation mountain ridges-plateaus.
Weather Discussion ( April 16-19 )
A gorgeous weather pattern for this time of year is being dominated by dry air and large day to night temperature spreads, especially amid mountain valleys.
First Wild Geranium ( Geranium spp. ) Blooms – April 15, 2016
Saturday morning temperatures dipped into the upper 20s to lower 30s in colder mountain valleys of Wise, Dickenson, and northern Scott counties, with heavy to patchy frost in many places such as Georges Fork, Meade Fork, Mill Creek, Indian Creek, Norton, Ramsey, Tacoma, etc….the official MIN reached 33 degrees in Clintwood.
Following a Saturday PM MAX of 75 degrees the following temperature drop has occurred in Clintwood tonight ( the official National Weather Service MMTS readings ):
Clintwood NWS Temperature Readings
4:00 PM 75.0 degrees
7:00 PM 61.8 degrees
8:00 PM 55.9 degrees
9:00 PM 50.9 degrees
10:00 PM 47.1 degrees
11:00 PM 44.3 degrees
12:00 Midnight 42.4 degrees
Air is dry with low dewpoints. This aids nocturnal temperature inversion formation, via radiational cooling and cold air drainage into valleys, which is actually rather common in the mountains ( i.e., having valleys colder than mountain ridges is rather common at night ).
A weak pressure gradient is also aiding these processes by generating decoupling of light boundary layer winds. In valleys these light winds are replaced by drainage flows generated by cooling air draining downslope, partly in response to the natural law of gravity, with the drainage flows combining to form stronger flows and even down valley mountain winds within main river valley channels. This forms a solenoidal circulation, much like the sea breeze does along the coast, with the flow direction of this circulation reversing after sunrise and onset of surface heating.
University Of Virginia’s College At Wise supported research through coming years will be working to develop a better understanding of micro-climatology of mountain valleys, cold air drainages, and the biodiversity that is associated with gradients within the biologically diverse High Knob Massif and Cumberland Mountains of this area.
*Temperature gradients and true differences associated with this landscape have been, and remain, poorly resolved by computer models and official forecasts for this complex landscape.
For example, the official NWS Forecast:
LEE-WISE-SCOTT-RUSSELL-WASHINGTON-
INCLUDING THE CITIES OF…JONESVILLE…WISE…NORTON…
GATE CITY…LEBANON…ABINGDON
330 PM EDT SAT APR 16 2016
TONIGHT…CLEAR. LOWS IN THE UPPER 30S TO LOWER 40S. EAST WINDS
10 MPH OR LESS.
neglects the colder mountain valleys and the milder mid-upper elevation mountain ridges & plateaus ( temperatures at Midnight being as cold as the official forecast minimums, while exposed middle-upper elevation ridges and plateaus will never drop down to this forecast range ).
A Species of Jumping Spider On Wild Geranium
This spider has 4 eyes in front, 2 in the middle and 2 in the back of his head. There is no way anything will “sneak” up on this simply amazing design of nature. He was “watching” me from this Wild Geranium leaf upon which he is standing.
The High Knob Landform and Clinch-Powell river basins are a core hotspot in the continental USA for the rarity & richness of limited range species, with truly extraordinary terrestrial & subterranean biological diversity.
Beetle Species In Woods – Late PM of April 16, 2016
Like many true insects, this species has a pair of compound eyes and a pair of simple eyes ( the simple eye being just above and a little to the right of his compound eye visible from this side ).
Conditions are unseasonably dry, for what is often one of the wettest times of the year, with this being reinforced once again by another blocking pattern ( the second major block of the flow field since March 1, 2016 to impact the southern Appalachians and eastern USA ).
Rain chance will eventually return, by later in the work week. Until then, enjoy this gorgeous weather ( just be prepared for some huge day-to-night temp differences if you live or work-play amid mountain valleys ).
Have a great Sunday.
It should be noted thatDr. William ( Bill ) Graypassed away Saturday ( April 16 ). A legendary forecaster-researcher of hurricanes and tropical weather-climate patterns. A true pioneer of his field. May God Bless the Gray family.
High clouds. Light winds becoming variable at 5-15 mph along middle to upper elevation mountain ridges. Large vertical temperature spread with low-mid 30s in colder mountain valleys verses mid 40s to lower 50s on exposed middle to upper elevation mountain ridges & plateaus.
Thursday Afternoon
Becoming mostly cloudy with a chance for scattered rain showers. Light ENE-ESE winds generally less than 10 mph. Mild with temperatures varying from the 50s at the upper elevations to the 60s to around 70 degrees in middle-lower elevations.
Thursday Night Into Friday Morning
Any scattered evening showers giving way to partly to mostly clear skies. SE-SSE winds 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges-plateaus. Temperatures mostly in the 40s ( a few 30s possible in valleys with calm winds into the morning ).
Friday Afternoon
Mostly sunny. Mild. Winds ESE-SE 5-10 mph, with higher gusts along mid-upper elevation mountain ridges. Temps varying from 50s in upper elevations to the upper 60s to lower-mid 70s in middle to lower elevations.
Friday Night Into Saturday Morning
Mostly clear. Frost in mountain valleys. Light ESE-SSE winds developing along mid-upper elevation mountain ridges-plateaus. Temperatures varying from upper 20s to lower 30s in colder valleys to the 40s along exposed mid to upper elevation mountain ridges-plateaus.
Weather Discussion ( April 12-15 )
The return of beautiful blue skies Tuesday afternoon set the stage for a frosty cold night, especially in mountain valleys, with widespread 20s observed by Wednesday morning.
A MIN of 27 degrees was recorded in Clintwood with low-mid 20s felt amid colder valleys of the Norton to Coeburn area and in upper elevations of the High Knob Massif-Burkes Garden corridor.
Dogwood Blossom ( Cornus florida ) In Cumberlands – April 12, 2016
An increase in high altitude clouds by afternoon hours of Wednesday was accompanied, for a change, by relatively light winds ( a welcomed change amid this windy spring ).
Large-flowered Trillium ( Trillium grandiflorum ) – April 13, 2016
Beautiful blooms of Trilliums are increasing but not yet at peak.
Macro Shot of White Daffodil ( Narcissus spp. ) – April 13, 2016
Temperatures as of 1:00 AM on Thursday had dropped into the upper 30s in Clintwood, heading toward a morning with low-mid 30s being more common in valleys ( verses the 20s observed on Wednesday AM ). By contrast, air temps were still in the 50s on exposed middle elevation ridges-plateaus like at Lonesome Pine Airport in Wise ( 1 AM April 14 ).
NAM 12 KM Model Total Rainfall Forecast
If you receive any rainfall today then consider yourself lucky, as models are clearly indicating that it will be localized and scattered in nature.
Perhaps the best chances will be from the High Knob Massif southwest & west by later today into early Thursday evening.
GFS Model Total Rainfall Forecast
A much drier than average spring pattern continues, which for now is good news for race fans heading to, or already at, Bristol to enjoy all the activities through coming days.
After today air will dry out once again with a notable drop in low-level dewpoints. This will again set the stage for mountain valley frost to become widespread Friday Night into Saturday morning.
A hard freeze will occur in mountain valleys during Tuesday Night into Wednesday Morning, with frost formation also possible in other places within Wise, Scott, Lee, Dickenson, Russell & Tazewell counties.
Heavy frost will again be likely in colder mountain valleys during Wednesday Night into Thursday Morning ( no frost is expected at exposed middle-upper elevations, especially on ridges-plateaus ).
Overnight Into Tuesday Morning
Showers developing. Windy. SSW-SW winds 10-25 mph, with higher gusts, shifting N into morning and decreasing to 5-15 mph. Turning cooler into morning with readings dropping into the 40s, except 30s at highest elevations.
Tuesday Afternoon
Becoming sunny ( deep blue skies ) and chilly. N-NNE winds 5-15 mph, with higher gusts. Temps varying from 40 to 45 at upper elevations to the mid-upper 50s ( milder at lower elevations in the Clinch, Powell, and Holston river valleys ).
Tuesday Night Into Wednesday Morning
Clear. Heavy frost formation in mountain valleys. Light northerly winds shifting SE-S along upper elevation ridges into morning at 5-10 mph. Temperatures varying from 20 to 25 degrees in colder mountain valleys to the lower-mid 30s ( mildest along middle elevation ridges-plateaus ).
Wednesday Afternoon
Mostly sunny. Light winds becoming ENE-NNE. Milder. Temperatures varying from low-mid 50s at the highest elevations to the middle-upper 60s.
Wednesday Night Into Thursday Morning
Partly to mostly clear. Winds ESE-SE at 5-15 mph along middle-upper elevation mountain ridges. Large vertical temperature spread with 20s in colder mountain valleys verses upper 30s to middle 40s along exposed ridges.
Weather Discussion ( April 11-14 )
Spring 2016 has been lacking in rain, but not in wind. This has been a very windy spring season, with some relief from these strong winds finally expected to develop through mid week as high pressure builds over the Appalachians.
Cluster of Rue-anemone ( Thalictrum thalictroides ) – PM of April 11, 2016
Any nature photographer is especially aware of wind, since out of the TOP 10 problems dealt with in taking high resolution shots the wind will generate ( directly or indirectly ) most of the problems.
Mayapple ( Podophyllum peltatum ) With Flower Bud On Top
The Mayapple above is newly emerged, with a flower bud that is still mostly visible above the leaves. This will change in coming days as these leaves continue to unfurl and rise above the bud.
Eventually a lack of rainfall will become a concern if precip totals do not begin increasing in coming weeks. Right now, with low evaporation rates and still cold nights, it is not a major problem ( outside of grass for hay that needs rain ).
A dry signal in the models is that higher totals have consistently been predicted a few days in advance of systems, to only decrease as the system in question gets closer in time to becoming reality. An exception, being the recent snowfall which was as productive as expected ( especially across upper elevations ).
European Model 850 MB Wind Field Analysis At 8 AM Monday – April 11, 2016
In a typical spring, wind like this would act to enhance the orographic forcing and make rainfall more productive. So when this does not happen within favored locations like the High Knob Landform corridor it is an important signal that should not be overlooked ( since past climatology dictates that this can be a dryness or drought precursor ).
European Model 850 MB Wind Field Analysis At 8 PM Monday – April 11, 2016
While another substantial cold front, with another notable temperature gradient, is pushing into the mountains only a relatively scrawny line of showers has formed.
European Model 850 MB TEMP-Surface Analysis At 8 PM Monday – April 11, 2016
Dryness this spring being directly connected to excessive wetness over the lower Mississippi Valley and Deep South as atmospheric compensation acts to force subsidence aloft over this region as air migrates outward away from deep convection to the southwest and south of the southern Appalachians.
Doppler Radar Base Reflectivity At 2:58 AM Tuesday – April 12, 2016
Deep blue skies will return today following this frontal passage as high pressure begins to take control. This will lead into a mid-late week period featuring development of easterly flow as the High shifts east and a wedge of cooler air ( at least by day ) sets up along and east of the Blue Ridge ( low dewpoint air and less clouds will act to generate cold nights along the western side of the Appalachians ).
While all locations will be cold Tuesday Night into Wednesday AM, mountain valleys will be coldest and will become the focus for the coldest air during nights throughout the remainder of this week.
Unseasonably Cold Temperatures Will Continue Into Sunday Morning
Minimum temperatures will drop into the 10s to lower 20s in colder locations into Sunday morning ( i.e., in mountain valleys and along the highest mountain ridges above 3300 feet ).
ALERT For Strong SW Winds Developing Along Middle To Upper Elevation Mountain Ridges-Plateaus During Sunday Night Into Monday
An increasing pressure gradient will develop strong ( ROARING ) winds at mid-upper elevations along the Cumberland Mountains from late Sunday into Monday. Mixing of roaring winds will also be possible in lower elevations northeast of the High Knob Massif and Tennessee Valley Divide via enhanced mixing and waves on SW flow ( e.g., Pound-Clintwood area ). Caution is advised.
Overnight Into Sunday Morning
Mostly clear ( increasing high clouds toward morning ). Unseasonably cold. Calm winds in valleys. NW-N winds shifting SSE-SW at 5-10 mph along mid-upper elevation mountain ridges-plateaus into morning. Temperatures varying from the 10s to lower 20s in colder valleys, and along highest ridges, to mid-upper 20s in milder sites.
Sunday Afternoon
Hazy sunshine ( mid-high clouds ). Milder. SSE-SSW winds 10-20 mph, with higher gusts. Temperatures varying from the 40s-low 50s in upper elevations to the upper 50s to mid 60s ( mildest in downslope locations of the Russell-Levisa Fork basins ).
Sunday Night Into Monday Morning
Mostly cloudy. Occasional rain showers. Strong winds developing across middle-upper elevation ridges. Winds SSW to SW 10-25 mph, with higher gusts, below 2700 feet. Winds SW 20-30 mph, with gusts to 40+ mph, on mountain ridges above 2700 feet. Temperatures widespread in the 40s. Wind chills in the 30s along upper elevation ridges.
Monday Afternoon
Partly to mostly sunny. Windy. SSW-SW winds 10-25 mph, with higher gusts. Temperatures varying from the 50s at upper elevations in the High Knob Massif to the upper 60s to middle 70s ( warmest at lower elevations in the Russell Fork and Levisa Fork basins ).
Monday Night Into Tuesday Morning
Rain developing. Windy. SSW-SW winds 15-25 mph, with higher gusts, shifting N into morning and decreasing to 5-15 mph. Mild evening temperatures in the 50s-60s turning cooler into morning with readings dropping into the 40s, except 30s at highest elevations.
Weather Discussion ( April 8-11 )
It is always interesting when spring meets winter amid the mountains, with this recent system not disappointing as a few periods of moderate-heavy rain-sleet-snow were even spiced with lightning-thunder late Friday into the early hours of Saturday.
Heavy Snow In High Chaparral of High Knob Massif – 8:38 PM on April 8, 2016
My friends Joe & Darlene Fields had 2″ of snow depth in the High Chaparral community of the High Knob Massif Friday Night into Saturday AM ( around 2.5 to 3.0″ of total fall ).
High Chaparral sits at an elevation of 3300 feet, or around 900 vertical feet lower than the crest of the High Knob Massif.
Snow Accumulation In High Chaparral At 9:52 PM on April 8, 2016
Total snowfall was a little greater than snow depth as some melting and enhanced settlement occurred on the unfrozen ground of April.
Ground Depth In High Chaparral of High Knob Massif – 9:07 AM on April 9, 2016
Enough snow accumulated to maintain a solid snow cover on upper northern slopes throughout the day of April 9, with snow melting off roads but continuing to cover heads of basins in the High Knob Lake, Big Cherry Lake & Norton Reservoirs at sunset.
Blooms Amid The Snow In High Chaparral – 9:08 AM on April 9, 2016
Snow amounts tapered to 1″ or less below 3000 feet, with Wayne & Genevie Riner reporting 0.3″ at Nora 4 SSE on the Long Ridge of Sandy Ridge. A total of 0.1″ fell in Clintwood with sticking during a thunder-snow-sleet downpour.
These shots were taken just before the moderate-heavy late PM and evening activity began during April 8.
Rue-anemone ( Thalictrum thalictroides ) In Various Stages – April 8, 2016
While more chilly shots, and frost, will be likely in coming weeks, perhaps this may be the coldest until later this year when the 2016-17 cold season begins. Perhaps.
European Model 850 MB TEMP-Surface Analysis At 8 AM Saturday ( April 9 )
Temperatures dropped below zero ( 0 degrees Fahrenheit ) at upper elevations of the High Knob Massif and Black Mountain amid gusts during Friday Night into Saturday Morning. True winter air!
Black Mountain MesoNET Temp-Dewpoint-RH Graphs at 4031 Feet
To put this into better perspective, this was the coldest air in the entire Northern Hemisphere ( relative to average ) for this time of year ( by far the coldest, as illustrated below by anomalies ).
European Model 850 MB TEMP Anomalies At 8 AM Saturday
Focus now shifts to warm air transport and a increasing pressure gradient that will crank up winds yet again by Sunday Night into Monday ( beginning at upper-middle elevations and mixing downward across the entire area over time during this period ).
NAM 12 KM Model 850 MB Wind Field Forecast At 2:00 AM Monday – April 11, 2016
The 850 MB wind field becomes very strong along & west of the mountains tonight into Monday, with 50-60 kt SW wind speeds developing from the Cumberland range west-north. This will generate a favorable settings for ROARING winds within the favored SW Upslope-Downslope flow corridor of the High Knob Landform and downstream locations ( where air sinks, for example, into the Russell Fork Basin ).
NAM 12 KM Model Total Precipitation During Next 84-Hours
Moisture increases aloft with high clouds Sunday and eventually a lowering of cloud bases by later Monday. Showers of rain, not snow, will become likely by late Monday into Tuesday ( during a windy period ).
ALERT For Unseasonably Cold Temperatures And Wind Chills Into Saturday – Accumulating Snow Will Also Be Possible Tonight Into Saturday Morning ( Especially Within Middle-Upper Elevations )
A prolonged period of cold conditions is expected from tonight into this weekend. Scattered hit-miss rain & snow showers will be possible today, with the best chance for more widespread snow by tonight into Saturday morning. A general 1-3″ of snow is possible at upper elevations, above 3000 feet, with 1″ or less in middle elevations below 3000 feet ( little to no snow accumulation is expected at elevations below 1500-2000 feet ).
Overnight Into This Morning
Partly to mostly cloudy. Chance for rain or snow showers. Turning colder. W-NW winds 5-20 mph, with higher gusts. Temperatures dropping into the 30s, with 20s above 3200 feet in elevation. Wind chills in the 10s & 20s ( coldest at the highest elevations ).
This Afternoon
Partly cloudy with increasing clouds into late afternoon. Rain & snow showers developing. W-SW winds 5-20 mph, with higher gusts. Temperatures varying from the 30s in upper elevations to the 40s to middle 50s ( warmest in the downslope locations from Pound-Grundy ). Wind chills in the 20s & 30s at elevations above 2500 feet.
Tonight Into Saturday Morning
Rain & snow, changing to snow in most locations late. A period of moderate-heavy snow possible above 3000 feet. WNW-NW winds 10-25 mph, with higher gusts, along mid to upper elevation mountain ridges and plateaus. Temps dropping into mid-upper 10s at highest elevations to the mid-upper 20s to lower 30s ( warmest at low elevations ). Wind chills from 10s to around 20 degrees, except 0 to 10 degrees along high mountain crest lines.
Weather Discussion ( April 7-8 )
A chilly and windy Thursday graced the mountain landscape in wake of needed overnight rains.
Nora 4 SSE – NWS Site In Middle Elevations ( Elevation 2650 feet )
Superintendent Andrew Greear and veteran technician Joe Carter reported 0.40″ of rainfall at the City of Norton Water Plant up to 9:00 AM on Thursday.
Superintendent Gary Hampton reported 0.63″ of rainfall at both the Big Stone Gap Water Plant and Big Cherry Lake Dam into the morning hours of Thursday.
A total of 0.18″ fell in Clintwood up to 7:00 AM on Thursday, with 0.36″ reported by Wayne & Genevie Riner at Nora 4 SSE.
Gusty showers mixed with snow in middle elevations, as mostly all snow fell at highest elevations in the High Knob Massif, during late afternoon-early evening on Thursday.
A temperatures of 41 degrees was observed at the Norton Water Plant at 6:30 PM as the activity began to develop.
The activity late Thursday afternoon formed beneath cold air aloft with puffy to towering cumulus clouds observed over Norton-Wise and Pound-Clintwood.
Rue-anemone Against Mossy Blanket – April 2016
Focus now shifts to the next wave and cold front that will cause rain-snow showers to develop in earnest by late today into tonight. Depending upon how this activity sets up, via the best moisture stream, a period of moderate-heavy snow will become possible across upper elevations in portions of the Mountain Empire ( with several inches of sticking snow at highest elevations into Saturday morning ).
The high resolution NAM 4 KM Model has a bulls-eye centered over the eastern West Virginia highlands, with more than 6″ ( locally up to 10″+ ) above 3000 feet in elevation. As past climatology shows, and is well documented locally, the model tends to under-estimate snowfall in upper elevations of the High Knob Massif.
NAM 4 KM Model Total Snowfall Forecast
At this time, it appears that any snow accumulations below 3000 feet will be limited to 1″ or less, with little to no sticking snow at elevations below 1500-2000 feet.
The coldest air with this system will be felt Friday Night into Saturday and Saturday Night into Sunday Morning.
NAM 4 KM Model MIN Temperature Forecast Saturday Morning
MIN temperatures will drop into the 10s in upper elevations of the High Knob Massif, with 20s widespread across most of the middle to lower elevations within the mountains & northeastern sections of the Great Valley ( from the TRI area northeastwards ).
NAM 4 KM Model MIN Temperature Forecast Sunday Morning
A prolonged period of cold conditions is expected from Thursday night into this weekend. Rain and snow showers will be possible Thursday night into Friday, with the best chance for snow by late Friday into Saturday AM. The potential for several inches of snow will exist in upper elevations, especially above 3300 feet, with a general decrease in sticking as elevation decreases below 3000 to 3300 feet ( a little sticking will be possible to around 1500-2000 feet, on the upslope side of the mountains, by Saturday AM ).
Late Evening Into This Morning
Rain with a chance for thunder. Locally heavy rainfall. A break in rain by the predawn-sunrise period. Winds SSW-W at 10 to 25 mph, with higher gusts, decreasing some toward morning. Temperatures dropping into the 40s, with 30s at highest elevations. Wind chills in the 20s & 30s.
Mid-Morning Through This Afternoon
Showers redeveloping. SW-W winds 10-25 mph, with higher gusts, along middle-upper elevation mountain ridges & plateaus. Chilly. Temperatures varying from 30s at upper elevations to the 40s to lower 50s ( milder south toward the Tri-Cities ). Becoming partly cloudy by mid-late afternoon or early evening. Wind chill factors in the 30s and 40s ( coldest at highest elevations ).
Tonight Into Friday Morning
Partly to mostly cloudy. Chance for rain or snow showers. Turning colder. WNW winds 5-15 mph, with higher gusts. Temperatures dropping into the 30s, with 20s above 3200 feet in elevation. Wind chills in the 10s & 20s ( coldest at highest elevations ).
Weather Discussion ( April 6-7 )
Increasing clouds & gusty conditions Wednesday developed in wake of a frosty cold morning in mountain valleys. A 41 degree temperature spread was observed in Clintwood from 24 degrees in the morning to 65 degrees in the afternoon.
Nora 4 SSE – NWS Site In Middle Elevations ( Elevation 2650 feet )
A more “narrow” temperature spread was observed along exposed mountain ridges and plateaus, with readings varying from the 30s into the 50s ( only upper 40s to about 50 degrees at the summit level of the High Knob Massif ).
JKL Doppler At 11:51 PM – Thursday ( April 6, 2016 )
The focus tonight is on needed rain, with brief downpours in places, that is moving across the mountains ahead of the first of two cold fronts ( with initially dry air in place, some evaporation occurred to make totals at the ground less than estimated by Doppler radar up to midnight ).
Black Mountain MesoNET Up To 1:00 AM Thursday – April 7, 2016
It is a wind driven, cold rain along high mountain crest lines with recent gusts between 40-50 mph ( driving wind chills into 20s ).
USA Water Vapor Image At 12:15 AM Thursday – April 7, 2016
A trough visible in the upper air over the eastern USA will deepen during the next couple of days, with anomalously cold air for this time of year spilling south over the region.
European Model 850 MB TEMP Anomalies-Wind Vector Forecast – 8 AM Saturday
Cold air transport reaches its maximum Friday Night into Saturday, with a NW flow pattern that will also help carry enough moisture south from open Great Lake waters to support some spring snowfall.
NAM Model 500 MB Vorticity Forecast At 2:00 PM Friday – April 8, 2016
Diffluence ( upper air divergence ) ahead of an approaching vorticity maximum diving toward the base of the upper air trough will begin to generate lower elevation rain showers and upper elevation snow showers during Friday afternoon, with increasing snow showers into Friday Night when snow levels will begin dropping toward the middle elevations.
At the current time, best accumulations are expected above 3300 feet in elevation with decreased sticking as elevation decreases below this level. There will be a period of time ( generally from midnight-sunrise Saturday ) when snow levels could reach down into the 1500-2000 foot zone for locations along the upslope side of the Cumberland Mountains ( with respect to NW flow ). Snow amounts are expected to be limited for most places by duration of these best conditions for snowfall ( best sticking being on above ground objects, grass, leaves, and northern slopes outside of the highest elevations ). Please stay tuned for updates.
The coldest air is expected along mountains ridges into Saturday morning, with coldest air in mountain valleys likely into Sunday morning. Prolonged below freezing conditions are expected in all locations, with anomalously cold wind chills across higher terrain locations during Friday night into Saturday.
A Hard Freeze Will Occur Overnight Into This Morning In Mountain Valleys. Increasing Winds Along Upper Elevation Mountain Ridges Will Mix Downward Onto Middle Elevation Ridges-Plateaus Toward Morning With Little To No Frost Expected
A wintry cold period is expected from Thursday Night into this weekend, with potential for snow accumulation along the upslope side of the mountains with respect to NW-N air flow. Significant snow accumulations will be possible at the highest elevations.
Overnight Into This Morning
Unseasonably cold. A large vertical temperature spread developing between frosty valleys and milder but windy middle-upper elevation mountain ridges. ESE-SSE winds increasing into the overnight-morning to 5-15 mph, with higher gusts, on middle elevation ridges-plateaus below 2700 feet. Winds S-SW at 10-20 mph, with higher gusts, along upper elevation mountain ridges. Temperatures in the 30s, or rising into the 30s following any evening drops, along exposed middle-upper elevation mountain ridges and plateaus. Temps falling through the 20s within mountain valleys. Wind chills in the 20s on upper elevation ridges.
This Afternoon
Increasing clouds. Milder & windy. Chance of a shower by late. SSE-SSW winds 10-20 mph, with higher gusts, along middle elevation ridges-plateaus below 2700 feet. Winds SSW at 15-25 mph, with higher gusts, on mountain ridges above 2700 feet. Temperatures varying from 40s to around 50 degrees in upper elevations to the middle 50s to low-mid 60s ( 55-60 degrees in Norton-Wise ).
Tonight Into Thursday Morning
Rain with a chance for thunder. Locally heavy rainfall. Winds SSW-W at 10-25 mph, with higher gusts, decreasing some toward morning. Temperatures dropping into the 40s, with 30s at highest elevations into morning.
Weather Discussion ( April 5-6 )
A unseasonably cold air mass Tuesday featured morning MINS that varied from around 20 degrees at the summit level of the High Knob Massif to around 30 degrees amid valleys in lower elevations to the north ( a little milder conditions were reported south toward the Tri-Cities ).
Scenic & Patriotic Setting In Town Of Clintwood – Afternoon of April 5, 2016
A gorgeous afternoon featured beautifully blue, cloud-free skies with temperatures reaching low-mid 40s in Norton-Wise and the upper 40s in Clintwood.
Nora 4 SSE – NWS Site In Middle Elevations ( Elevation 2650 feet )
The setting tonight features temperatures falling through the 20s in colder mountain valleys ( 28 degrees at Clintwood 1 W as of Midnight ) as highest ridges become increasingly windy with near steady to rising temperatures.
An increasing vertical temperature spread between colder valleys and milder ridges will develop overnight into this morning. The off-setting factor along upper elevation ridges being an increase in wind chill factors ( making it feel like 20s or colder in gusts ).
Black Mountain MesoNET Up To 12:15 AM Wednesday – April 6, 2016
Temperatures will rise dramatically into today as southerly winds increase and mix downward across the entire area, with downslope locations in the Russell-Levisa Fork basins likely rising into the 60s ( marking 40+ degree temperature rises between this morning and this afternoon ).
Rain chances will increase dramatically by late today into tonight as the next weather system approaches. A chance for lightning-thunder and locally heavy rainfall will exist during the Wednesday Night-Thursday AM period.
NAM 12 KM Model Total Precipitation Forecast To 8 AM Saturday – April 9, 2016
Precipitation totals could top 1.00″, with the final period of this forecast cycle, from Thursday Night into Friday Night, featuring increasingly cold air and the chance for snow at higher elevations ( with snow levels dropping over time into middle elevations by late Friday Night into Saturday Morning ).
GFS Model Total Precipitation Forecast To 8 AM Saturday – April 9, 2016
