ALERT For Freezing Fog At Upper Elevations Above 3000 to 3300 Feet Through Mid-Morning Tuesday
Cloud bases generally remained near to just above the Wise and Sandy Ridge plateaus Monday Night into this morning, with fog and freezing fog at elevations above 3000 to 3300 feet in elevation ( temps in the 20s at highest elevations ) within locations along and north of the High Knob Massif and Black Mountains.
The low cloud deck, which has now kept highest elevations in the High Knob high country within dense fog for nearly 48 consecutive hours, will finally begin to break up later Tuesday. If mixing is slow this will be a slow dissipation versus if vertical mixing and orographic waves develop.
Partly to mostly clear, then becoming cloudy ( low, upslope clouds and areas of dense fog ). Winds NW-N at 5-15 mph, with some higher gusts, on mid-upper elevation mountain ridges & exposed plateaus. Turning colder. Temperatures varying from 20 to 25 degrees at highest elevations to the middle 30s. Wind chills in the 10s & 20s across mid-upper elevation mountain ridges-exposed plateaus ( single digits and 10s along high mountain crest lines ).
Friday Afternoon
Partly to mostly sunny. Cold. N-NE winds 5-10 mph, with some higher gusts. Temperatures varying from the 20s in upper elevations to the middle 30s to around 40 degrees. Milder south into the Great Valley.
Friday Night Into Saturday Morning
Mostly clear ( high clouds possible ) and unseasonably cold. Increasingly large vertical temperature spread developing between cold valleys and milder mountain ridges. Light & variable winds becoming southerly at 5-10 mph along mid-upper elevation mountain ridges. Temps varying from the upper 10s to mid-upper 20s, except as cold as 10-15 degrees in colder upper elevation valleys versus temps rising to near or above freezing along high mountain crest lines.
Saturday Afternoon
Sunshine & high altitude ice crystal clouds. Winds SSE-SSW at generally less than 10 mph. Temperatures varying from the upper 30s to lower 40s in upper elevations to the upper 40s to lower 50s.
Saturday Night Into Sunday Morning
Partly cloudy ( high altitude ice crystal clouds ). Large vertical temperature spread between cold valleys and milder mountain ridges. Winds SSW-SW at 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures varying from upper 10s to lower 20s in the colder valleys to the 30s to around 40 degrees on exposed mid-upper elevation mountain ridges-plateaus.
A changing upper air pattern across North America and the Northern Hemisphere will increase the potential for a shift into wintry conditions by Thanksgiving week. Stay tuned for updates on this evolving hemispheric pattern.
Weather Discussion ( Arctic Brush )
A brush with true arctic air is featured during this forecast period in wake of some 36+ hours with dense fog at middle to upper elevations along & north of the High Knob Massif and Tennessee Valley Divide.
High Knob Massif Webcam – University Of Virginia’s College At Wise
Check out the HUGE difference in conditions experienced from Wednesday at 5:48 PM ( above ) to Thursday at 5:20 PM ( below ). Another period with development and drop of low cloud bases is expected into Friday morning as an arctic cold front pushes across the mountains.
A few snow flurries will even be possible in favored upslope locations; although, I have left this out of my forecast above since there will be only a brief period where this could occur with bone dry arctic air surging in behind the arctic front.
High Knob Massif Webcam – University Of Virginia’s College At Wise
Although the main push of coldest air will remain to the northeast of the southern Appalachians, this area will get into true arctic air with dewpoints by Saturday morning plunging into 10s at the surface, and as low as -10 degrees Fahrenheit at the summit level of the High Knob Massif.
Under ideal conditions the coldest high valleys could drop into single digits; however, conditions may not be quite ideal with potential for high altitude ice crystal clouds aloft and mixing within the PBL being yet to be determined. Still the possibility exists for some very cold temps in favored frost pockets with readings dropping under 10 degrees.
European 51-Member Ensemble MEAN 500 MB Height Anomalies: Days 1-5
The upper air pattern does not seem compatible with all the coldness expected in coming days; however, this illustrates that not only do we not live at 500 MB ( around 18,000 feet ) but that the arctic is charging up with bitter air.
European 51-Member Ensemble MEAN 850 MB Temp Anomalies: Days 1-5
This is important since upper air blocking will be changing at high latitudes during the next week to 10 days, such that by the weekend before Thanksgiving, and the week of the holiday, the stage will be set for much colder conditions to develop across the eastern USA.
European 51-Member Ensemble MEAN 500 MB Height Anomalies: Days 6-10
If this trend is real, it will become more evident in forecasts at 6-10 day time frames as we progress through next week.
European 51-Member Ensemble MEAN 850 MB Temp Anomalies: Days 6-10
A key feature above being bitterly cold air across western Canada and portions of Alaska.
I do not know what the upcoming winter will bring when all is said and done ( by next April-May ), but do have increasing confidence that the pattern starting to develop now, and within the next 1-2 weeks, could represent a big-time shift into winter for at least the latter portion of November into December.
My initial feeling is that the potential exists for more winter to occur between now and January 1 than was experienced during the anemic 2016-17 season. This remains, of course, to be seen and will become more clear as the current pattern changes during the next one to two weeks across the eastern USA.
*A prolonged period of dense fog ( low clouds ) will develop as colder air invades the front range of the mountains from late Tuesday into Wednesday on upsloping northerly winds. A cold, damp & raw feeling day is expected Wednesday when air temps will struggle in the 30s to lower 40s in locations along and north of the High Knob Massif & Tennessee Valley Divide, with milder conditions leeward of the mountains into river valleys of the Clinch, Holston and Great Valley.
Overnight Into Wednesday Morning
Colder. Rain developing during the predawn-morning. Dense fog at mid-upper elevations along and north of the High Knob Massif and Tennessee Valley Divide. NNW-NNE winds at 5-10 mph, with some higher gusts. Temps falling into the 30s to around 40 degrees. Wind chills dropping into the 20s to lower 30s at the highest elevations.
*The potential for some local freezing rain will exist along northern slopes-crest lines of the High Knob Massif with cooling on northerly upslope flow into the lower 30s.
Wednesday Morning Into The Afternoon
Rain tapering to showers-drizzle. Nasty & bone chilling. Low cloud bases with dense fog at mid-upper elevations along-north of the High Knob Massif & Tennessee Valley Divide. Winds N-NE at 5-10 mph. Temperatures varying from lower 30s to lower 40s. Some breaks in the overcast possible leeward of the High Knob Massif-Black Mountain by mid-late afternoon. Wind chills in the 20s to around 30 degrees at upper elevations.
Wednesday Night Into Thursday Morning
Low clouds ( widespread dense fog continuing at mid-upper elevations ). Chilly. A chance of light showers and drizzle. Light N-NE winds becoming variable in direction at upper elevations. Temperatures near steady or slowly rising in the 30s to lower 40s.
Thursday Morning Into The Afternoon
Becoming partly to mostly sunny. Winds WNW-NW at 5-10 mph, with some higher gusts. Temperatures varying from the lower 40s to the lower 50s.
Thursday Night Into Friday Morning
Partly to mostly clear ( a period of increased low clouds possible into the morning ). Winds NW-N at 5-15 mph, with some higher gusts, on mid-upper elevation mountain ridges and exposed plateaus. Temperatures varying from the low the middle 20s to the middle 30s. Wind chills in the 10s in upper elevations ( near 10 degrees highest peaks in gusts ).
Friday Afternoon
Partly to mostly sunny. Cold. N-NE winds 5-10 mph, with some higher gusts. Temperatures varying from the 20s in upper elevations to the middle 30s to around 40 degrees. Milder south into the Great Valley.
Friday Night Into Saturday Morning
Mostly clear ( some high clouds possible ) and unseasonably cold. Light and variable winds on mountain ridges. Temps varying from the upper 10s to mid-upper 20s, except as cold as 10-15 degrees in colder upper elevations valleys.
Weather Discussion ( Nasty & Cold )
Wednesday Afternoon Update
High Knob Massif Webcam – University Of Virginia’s College At Wise
Dense fog has now covered hundreds of square miles for 24 consecutive hours across northern Scott County, southern-central Wise County & central-southern Dickenson County.
Lonesome Pine Airport With 24 Hours of Dense Fog & Counting
The National Weather Service’s recognition of this:
Morristown TN Official NWS Forecast
is NONE!
I typically never say anything on this site, but as you see and experience this, drive in this, and know how widespread it is for 24-hours then ask this question:
If this occurred in the Great Valley, from Morristown to the Tri-Cities, what would be the resulting action?
Likely – Official Recognition with a Dense Fog Advisory.
It is not just MRX, but also RLX; however, MRX has the largest population impacted by these events, even though every single person COUNTS and a small community is just AS IMPORTANT as a big city which is my bottom line.
Nora 4 SSE on Long Ridge
A raw, damp chill has, of course, been the other big story. Check out today’s temperature trend from Nora 4 SSE on Long Ridge of Sandy Ridge, where dense fog has also been persistent all day long.
Temperatures at upper elevations in the High Knob Massif have been mainly in the mid-30s all day ( 33 to 38 degrees ).
Fog will continue through this evening, and it is looking more likely that it will continue into Thursday before the cloud bases finally lift.
Please slow down and be extremely careful as it has been difficult to see vehicles on the road, not to even mention other things like people or deer!
Previous Discussion
Widespread low clouds ( dense fog ) are about as thick as they get across mid-upper elevations along and north of the High Knob Massif & Tennessee Valley Divide as colder air is being lifted vertically over a moist mountain landscape.
I had this well forecast in advance, reference my 110617 Forecast for previous details on this nasty period of weather conditions.
High Knob Massif Webcam – University Of Virginia’s College At Wise
Conditions will become colder and even more nasty as a round of rain develops overnight into Wednesday morning.
Lonesome Pine Airport In Wise – Dense Fog For 12 Consecutive Hours & Counting
Temperatures along northern slopes and crest lines in the high country will be borderline, or very close to freezing, as rain redevelops overnight into Wednesday morning. Close enough that folks traveling along State Route 619, 160, and Routes 238, 237, as well as others above 3300 feet, should be alert for possible slick patches amid the pea-soup fog.
Black Mountain Mesonet – Elevation 4031 Feet
If low clouds ( fog ) hang tough in the upslope flow through the day Wednesday then temperatures in Norton-Wise will hover in the nasty 30s to around 40 degrees, with somewhat milder conditions at lower elevations and within locations downslope and leeward of the High Knob high country and Tennessee Valley Divide.
A low cloud deck and neutral to slight warm air advection may help hold temperatures near steady Wednesday Night into Thursday morning in advance of the next push of even colder air set to arrive by Friday.
If the warm advection can out-weigh the neutrality, then rises in cloud base levels may also occur during the period of Wednesday Night-Thursday AM with eventual break-up of the cloud deck expected during the day Thursday.
European Model 850 MB Temp Anomaly Analysis at 7 PM Tuesday – November 7
The mountain area will be on the fringe of a big blob of much below average temperatures ( seen above ) over the western portion of Canada by Friday, with the core of the very coldest air extending from northern West Virginia northeastward into the New England states.
This will set the stage for the coldest temperatures of this season, to date, heading into Friday Night & Saturday AM, with 10s and 20s widespread. Favored frost pockets will have the chance, at least, to plunge toward 10 degrees if skies are clear and winds decouple ( even colder readings will be possible, especially where 850 MB temps are colder toward the eastern-northern highlands in West Virginia; however, low clouds from Great Lake moisture could be a hindrance there, along with gustier 850 MB winds ).
Meanwhile,
High Knob Massif Webcam – UVA-Wise – Can Not Even See The Closest Road
Please use extreme caution in this very dense fog.
ALERT For Dense Fog At Mid-Upper Elevations Along And North Of The High Knob Massif-Tennessee Valley Divide From Late Tuesday Afternoon Into Wednesday
*A prolonged period of dense fog ( low clouds ) will develop as colder air invades the front range of the mountains from late Tuesday into Wednesday on upsloping northerly winds. A cold, damp & raw feeling day is expected Wednesday when air temps will struggle in the 30s to lower 40s in locations along and north of the High Knob Massif & Tennessee Valley Divide, with milder conditions leeward of the mountains into river valleys of the Clinch, Holston and Great Valley.
Monday Night Into Tuesday Morning
Low clouds. Turning cooler during the evening, especially along and north of the High Knob Massif-Tennessee Valley Divide. Then rain developing overnight, with a chance of thunder. Downpours likely. N-NE winds at 5-10 mph, with some higher gusts, into the early overnight shifting SSE at 5-15 mph, with higher gusts, by morning. Temperatures falling into the upper 40s to low-mid 50s.
Tuesday Morning Through The Afternoon
Rain, heavy at times, through the morning. Thunder possible. Rain tapering to showers into the afternoon. Winds SSE-SSW shifting to NW-N by mid-late afternoon below 3200 feet at generally less than 10 mph. SSE winds shifting W-WNW at 5-15 mph, with higher gusts, at upper elevations above 3200 feet. Temperatures in the 50s to around 60 degrees, turning chilly during mid-late afternoon ( milder south into the Great Valley ).
Tuesday Night Into Wednesday Morning
Low clouds. Light showers or drizzle. Turning colder. Another period of dense fog likely at mid-upper elevations along and north of the High Knob Massif-Tennessee Valley Divide. NNW-NNE winds at 5-10 mph, with some higher gusts. Temps falling into the 30s to around 40 degrees. Wind chills dropping into the 20s to lower 30s at the highest elevations.
Wednesday Morning Into The Afternoon
Low cloud bases with areas of dense fog at mid-upper elevations along & north of the High Knob Massif and Tennessee Valley Divide. Cold & damp. Drizzle possible. Winds N-NE at generally less than 10 mph. Temperatures varying from the lower 30s to lower 40s ( coldest at the highest elevations ). Some breaks in the overcast possible leeward of the High Knob Massif-Black Mountain. Wind chills in the 20s to around 30 degrees at high elevations.
Weather Discussion ( Wet & Colder )
A mild, wet beginning to November will transition into a wet and cold pattern into mid-week. Locally heavy rain amounts will be possible Tuesday during this transition.
Clouds Engulfing Big Cherry Valley In High Knob Massif – November 4, 2017
Folks living along and north of the High Knob high country and adjacent Tennessee Valley Divide need to get use to this view as low cloud bases become a persistent feature by late Tuesday into Wednesday, on upsloping northerly air flow.
High Knob Massif Webcam – Dense Fog ( Clouds ) On The Wise Plateau
The interaction of abundant low-level moisture with colder air will combine with lifting on upslope flow to generate a widespread low cloud deck into Tuesday Night-Wednesday, especially in locations ( of course ) on the rising air side of the Cumberland-Allegheny Front range.
NAM 12 KM Model Total Rainfall Forecast
Forecast models have been struggling to pin down where heavier rains will fall through Tuesday, but amounts of more than 2.00″ ( when including Monday ) are certainly possible in some locations ( around 1.30″ fell on Eagle Knob of the High Knob Massif Monday ), especially in those zones which have been ( and are being now ) pre-conditioned by condensation on rising air ( e.g., the lifting zone of the High Knob Massif-Black Mountain corridor to include the City of Norton & Towns of Wise, Appalachia, Big Stone Gap etc…).
European Model 850 MB Analysis At 7 AM Monday – November 6, 2017
A wave of low pressure developing over Texas, as seen above at 7 AM Monday, will spread a new wave of rain across the mountain region into Tuesday morning.
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 1-5
This will mark the beginning of a colder trend; however, due to upper air blocking over the Aleutians-Bering Sea sector, the brunt of the cold will dive into New England later this week as general -PNA ( negative Pacific North American oscillation ) is maintained.
European Model 500 MB Height Anomalies At 7 AM Monday – November 6, 2017
The current 6-10 day trend is for near to a little above average temperatures locally, with above average temps forecast across much of the nation between the Rockies and Appalachians ( below ) by the 51-member ensemble mean.
Statistically, and in theory, a 51-member MEAN forecast should be more accurate than any individual model forecast. While this is not always true, more often than not the use of the MEAN of a large group is best when doing longer-range outlooks.
A notable exception to the above being when atmospheric changes climatologically proven by history to alter a particular pattern can be picked out by a forecaster in advance of later model shifts. An example of what I mean by this will be cited below with respect to the potential for changes heading toward Thanksgiving Week and early December that are only being hinted at by the best models.
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 6-10
Beyond the 6-10 day period there are increasing signs that high latitude blocking will begin changing its orientation, with a cross-latitude bridge of positive height anomalies forming from Northern Europe into Eastern Siberia along with a notable and increasingly negative trend in both the AO and NAO teleconnections, which could signal a more important pattern shift down the road ( especially if the current -PNA dissipates, which is NOT yet being forecast ).
Building of bitter air across northwestern Canada and parts of Alaska during next week in combination with formation of blocking near Greenland, can be preliminary indicators of Arctic Outbreaks into the continental USA. Stay tuned for later updates on this evolving pattern.
Reference my 110417 Forecast for details about why blocking over the Aleutians-Bering Sea is important to SE USA conditions. Note that cold can occur given this mean pattern, with 0 degrees being observed in high valleys of the High Knob Massif as late as March 16 this year; however, the type of pattern observed during Winter 2016-17 was not favorable for sustained cold-snowy weather.
ALERT For Strong ( ROARING ) SW Winds At Mid-Upper Elevations Into Monday Morning In Advance Of A Line Of Showers-Thunderstorms. Caution Is Advised.
Strong SW winds will continue to blow into the overnight ahead of an approaching line of showers-thunderstorms. Expect wind gusts of 30-40+ mph to continue, and to also mix downward into some SW flow wave zones across the northern portions of Wise and Dickenson counties.
An outbreak of severe thunderstorms is looking likely by later this weekend over the Ohio Valley, with potential for one or more bowing squall lines. The eastward progress of this will need to be watched as it approaches the western side of the Appalachians by Monday.
ALERT For Areas Of Local To Widespread Dense Fog Into Saturday Morning
Overnight Into Saturday Morning
Cloudy. A chance of rain showers, especially by morning. Low clouds with dense fog at upper elevations, and local to widespread at other elevations. Light winds. Temperatures widespread in the 50s.
Saturday Morning Into The Afternoon
Cloudy. A chance of rain showers, especially along and southeast of the Tennessee Valley Divide and High Knob high country. Breaks in the overcast possible by mid-late afternoon, especially north of the high terrain. SSE-SSW winds 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges & plateaus. Temperatures varying from 50s in upper elevations to the middle-upper 60s ( warmest at lower elevations in the Russell Fork-Levisa Fork basins ).
Saturday Night Into Sunday Morning
Partly-mostly cloudy in the evening, becoming cloudy overnight into the morning with a chance of drizzle or showers. SSE-SSW winds 5-15 mph, with higher gusts, on mountain ridges below 2700 feet. S-SW winds 10-20 mph, with higher gusts, on mountain ridges above 2700 feet. Mild for the season with temperatures mostly in the 50s. Area of dense fog possible, especially at high elevations along the High Knob Massif-Tennessee Valley Divide.
Sunday Afternoon Updated
Partly-mostly cloudy. Unseasonably warm & gusty. S-SW winds 10-20 mph, with higher gusts. Temperatures from the 50s to low 60s at upper elevations to the upper 60s to low 70s ( warmest at lower elevations in the Russell & Levisa Fork basins, as well as to the south into the Great Valley ).
Sunday Night Into Monday Morning
Partly-mostly cloudy & windy. A chance of showers and thunderstorms, especially overnight into Monday. Winds S-SSW 10-20 mph, with higher gusts, along mountain ridges-plateaus below 2700 feet. Winds SW at 15-25 mph, with higher gusts, on mountain ridges above 2700 feet.
Transition into a colder weather pattern is expected next week, with temperatures trending back toward near to below average.
Weather Discussion ( Moist-Mild )
Sunday Evening Updated Discussion
Strong SW winds are roaring over mountain ridges-exposed plateaus in the Cumberland Mountains this evening and will continue into the overnight as a line of showers and thunderstorms approaches the Appalachians.
Black Mountain Mesonet
Caution is advised to be extra careful of breaking limbs or trees, especially in the mid-upper elevations, but also at some lower sites in climatologically favored zones where mountain waves on SW winds break downward, such as within the Pound-Clintwood corridor and locations lying downstream of the High Knob Massif – Black Mountains.
Previous Discussion
A moist & unseasonably mild November air mass will grip the mountain landscape throughout this weekend, with a notable increase in gusty S-SW winds expected by Sunday into early Monday in advance of a cold front.
Storm Prediction Center Risk Regions – Sunday Into Monday Morning
A rather large region from the Ohio Valley and lower Great Lakes into the middle Mississippi Valley will come under the gun for potential severe thunderstorms by Sunday. While the strongest activity is currently expected to remain west of the mountains, any east-southeast moving squall lines will need to be monitored as they cross into Kentucky.
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 1-5
Storminess will be occurring in advance of a major transition in the upper air pattern during next week; however, still not the complete change upstairs ( as highlighted below ).
This change being forced to occur as the atmosphere fights to establish some type of balance, between a simply HUGE autumn temperature gradient across North America ( noted above in the region between the eastern front range of the northern Rockies and the southern Plains & Mexico ).
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 6-10
A shift from unseasonably mild to below average temperatures is currently forecast by the MEAN of European Ensembles.
European Model 500 MB Height Anomalies at 8 AM Friday – November 3, 2017
However, before winter fans get carried away, it should be pointed out that anomalously strong 500 MB heights over the Aleutians and Bering Sea is present currently and is forecast to remain in place through the next 10 days.
*Observe how strikingly similar the current pattern ( above ) is to that observed ( in the mean ) during Winter 2016-17 ( below ).
Observed 500 MB Height Anomalies – Dec to Feb of Winter 2016-17
If you do not understand why this is important, simply look back at the MEAN pattern observed during last winter and note that there is a strong correlation between positive 500 MB height anomalies with a Bulls-eye type of configuration over the Aleutians & Bering Sea and milder than average weather conditions in the eastern-southeastern USA.
500 MB Height Anomaly Pattern During February 2015
If the positive 500 MB height anomaly pattern should lose its “bulls-eye” type of configuration, becoming elongated as observed above, during February 2015, then a completely different result would occur ( much different! ).
A negative trend in the Arctic & North Atlantic Oscillations is forecast to occur during the next 1-2 weeks; however, due to persistence of a “bulls-eye” type of 500 MB height anomaly centered over the Aleutians-Bering Sea a -PNA pattern will continue to fight against eastern USA troughing.
It remains early, with the high latitude winter pattern just now taking shape, such that current blocking does not mean that the outcome will be the same as last winter ( every winter season is different, so stay tuned for updates as mixed signals are being teleconnected from the Arctic region at present…some which favor a “bad” winter and some favoring another mild season ).
Partly to mostly clear. Winds shifting to NW and decreasing to generally less than 10 mph along mountain ridges-exposed plateaus ( with some higher gusts along the highest ridges ). Temps varying from 20 to 25 degrees in colder valleys at upper elevations to the 30s by morning on exposed middle elevation ridges & plateaus. A period of rime formation possible along highest NW facing crests.
Tuesday Afternoon
Mostly sunny and seasonally chilly. Light & variable winds. Temperatures varying from upper 30s to lower 40s within upper elevations to the low-middle 50s ( warmer southward into the Great Valley ).
Tuesday Night Into Wednesday Morning
Mostly clear during the evening, then increasing clouds overnight into morning. A rapid evening temp drop in mountain valleys. SSE-SW winds 5-15 mph, with higher gusts along mid-upper elevation mountain ridges and exposed plateaus. Temperatures varying from the 20s-lower 30s in colder mountain valleys to the mid-upper 40s. Temps rising into the overnight in valleys that recouple to the boundary layer wind field. Wind chills in the 30s along high mountain crest lines.
Wednesday Afternoon
Mostly cloudy. Chance of rain showers, especially near and west of the Virginia-Kentucky stateline. Winds S to SW at 5-15 mph, with higher gusts. Temperatures varying from upper 40s to lower 50s in upper elevations to the upper 50s to low 60s. Wind chills in 30s-low 40s at highest elevations.
Wednesday Night Into Thursday Morning
Partly-mostly cloudy. Chance of rain showers. Gusty across ridges. Winds SSE-S at 5-15 mph, with higher gusts, along mountain ridges-plateaus below 2700 feet. SSW-SW winds 10-20 mph, with higher gusts, along mountain ridges above 2700 feet. Temperatures in the 40s and 50s ( coolest within mountain valleys sheltered from wind ).
Weather Discussion ( Wintry Recap )
The first real wintry blast of the season generated some nice scenes across the mountain area, mainly at mid-upper elevations, where nearly all accumulations occurred.
Long Ridge of Sandy Ridge – Elevation 2650 Feet
As I expected, the greatest amount of frozen precipitation and snow occurred along the Cumberland-Allegheny Front corridor, where air is initially lifted into upper elevations of the Appalachians on NW-N upslope flow. Snow amounts became less leeward of these front ranges, which included a notable decrease east of the spine of the Great Smokies into western North Carolina. The greatest snow depth reported reached 8″ at Canaan Mountain in northern West Virginia.
Storm Event Reports
Tri-Cities, TN NWS: 0″ ( 0.89″ Storm Total Precip )
Clintwood 1 W NWS: Trace ( 1.28″ Storm Total Precip )
*City of Norton WP: 1.0″ ( 1.54″ Storm Total Precip )
**Eagle Knob of High Knob Massif: 3.0″ ( 0.56″+ of Frozen Precipitation )
Mount LeConte, TN: 3.0″ ( 1.70″ Storm Total Precip )
Canaan Mountain, WV: 8.4″ ( 2.41″ Storm Total Precip )
Beech Mountain, NC: 1.0″ ( 2.21″ Storm Total Precip )
Mount Mitchell, NC: 0.5″ ( 3.61″ Storm Total Precip )
*Mean depth at the City of Norton Water Plant, at the northern base of the High Knob Massif ( elevation 2342 feet ), reached 0.5″ with around 1.0″ ( 0.10″ water equivalent ) of total snowfall.
Eagle Knob of High Knob Massif At 3:37 AM Monday – October 30, 2017
**Freezing rain initially generated icing before a change to snow at the summit level. More than 0.56″ fell in frozen form, with more than 0.30″ as snow water equivalent. The greatest depth of snow developed between sunset Sunday and the early hours of Monday with additional snow showers that recovered roads. This event produced the first single digit wind chills in the high country.
European Model 850 MB Temp Anomalies At 8 AM Monday – October 30, 2017
It was a cold start to the work week with Monday AM temperatures varying from upper 10s to upper 20s within the Norton-Wise and High Knob Massif area ( including in Clintwood with a MIN of 28 degrees over bare ground ).
European 51-Member Ensemble Mean Temp Anomalies Forecast: 8 AM Nov 2
Chilly conditions begin diminishing during late week into next week as the large eastern USA upper air trough does a retrograde movement into western North America.
European 51-Member Ensemble Mean 500 MB Height Anomalies: 7 AM Nov 6
The main uncertainty in the forecast during coming days will be how far east do waves of rain get, and that will be dependent in part upon where an upper ridge axis becomes aligned as noted above at 7 AM Monday ( 7 AM since time will have fallen back 1-hour to yield earlier model runs ).
A wet, stormy pattern will develop within the baroclinic zone between the Rockies and Appalachians, with details regarding the placement of this zone to be better resolved by models in coming days. Stay tuned for later updates.
ALERT For Freezing Fog-Rain At High Elevations Saturday Evening Prior To A Change Over Into Snow During The Overnight Into Sunday Morning
Air temperatures reached 32 degrees at the summit level of the High Knob Massif prior to sunset Saturday. Caution Is Advised for those traveling State Route 619, Routes 238, 237, and other high country roads, at elevations above 3500 feet, through Saturday evening due to dense fog and sub-freezing temperatures.
ALERT For Snow Accumulations of 1-3″ Above 3000 Feet Elevation, With Locally Higher Amounts, Into Sunday-Sunday Night ( With Riming ). Snow Depths Of 1″ or Less Are Expected At Elevations Below 3000 Feet. Unseasonably Cold Conditions, With Temps Remaining Below Freezing Through Sunday At The Upper Elevations Will Combine With Gusty NW-N Winds To Generate Low Wind Chill Values.
Rain will change to snow overnight into Sunday morning as a low pressure system develops east of the mountains to increase NW-N upslope flow into the windward side of the Cumberland-Allegheny and Blue Ridge ranges. Greatest snow accumulations will occur in upper elevations, above 3000 to 3500 feet, with lesser amounts in middle elevations between 2000-3000 feet ( especially along the Cumberland-Allegheny mountain ranges where sticking snow levels will be the lowest ). While the woods, grass, and above ground objects will tend to accumulate the most snow, some roadways at high elevations will also become snow covered.
Saturday Night Into Sunday Morning
Cold & blustery with rain showers changing to snow showers and flurries ( evening freezing rain & fog at the highest elevations ). NW-NNW winds 5-15 mph, with higher gusts, along middle to upper elevation mountain ridges and plateaus. Temperatures dropping into the low 20s to lower 30s ( coldest at highest elevations ). Milder south into river valleys of the Clinch, Powell, Holston ( Great Valley ) . Wind chills in the 10s & 20s, except dropping to around 10 degrees or lower on peaks above 3600 feet. Rime formation in the upper elevations above 3300 feet.
Sunday Morning Through The Afternoon
Gusty & unseasonably cold. Snow showers & flurries, especially along the upslope side of the mountains. NW-N winds at 10-20 mph, with higher gusts, on middle to upper elevation mountain ridges-plateaus. Temperatures varying from the 20s in upper elevations to the mid-upper 30s. Low cloud bases with riming at high elevations. Winds chills in the 10s and 20s to lower 30s, except single digits in gusts on high peaks above 3600 feet.
Sunday Night Into Monday Morning
Mostly cloudy with a chance of snow showers & flurries. WNW to NW winds 5-15 mph, with higher gusts. Temps widespread in the 20s, except 10s possible on highest crest lines of the High Knob Massif ( and in colder high valleys if any predawn-sunrise clearing occurs ). Wind chill factors in the 10s & 20s along mountain ridges, except locally lower on highest peaks.
Monday Afternoon
Mostly sunny. Gusty. SSW-SW winds 10-20 mph, with higher gusts ( especially along mountain ridges-plateaus ). Temperatures warming into the lower 40s to lower 50s. Winds chills in 20s and 30s ( coldest highest elevations ).
Weather Discussion ( Wintry Blast )
Sunday Afternoon Update
A wintry day has featured widespread sticking snow at elevations above 2000 to 2500 feet across Wise-Dickenson counties into northern Scott County, with some fairly large snow flakes falling in the more vigorous showers.
Snow Falling At The University Of Virginia’s College At Wise
My friend Wayne Riner submits a great shot showing snow on the pumpkin, at a fitting time of the year too!
Snow On The Pumpkin – Long Ridge of Sandy Ridge – Elevation 2650 Feet
A combination of snow-sleet has been falling in Clintwood with only brief sticking at 1560 feet elevation. The sticking snow has been mainly above 2000 feet.
Eagle Knob of High Knob Massif At 4:09 PM on October 29, 2017
The greatest snowfall amounts reported so far have been around 2″ at upper elevations in the high country.
Snow has even covered the road and graveled areas up on Eagle Knob, where the air temperature has been hovering around 25 degrees all day at top of the high country. The best sticking, as figured, being in woods and over grass.
Expect some more sticking at mid-upper elevations through Sunday evening, with the possibility that the lower limit of sticking ( at least on above ground objects ) may slip just under 2000 feet across the upslope zone before moisture wanes in the low-level flow overnight into Monday AM.
Previous Discussion
The beauty of a mid-autumn sunset was forgotten into Saturday as conditions turned simply NASTY within the mountains, with low cloud bases, rain, and falling temps.
Beautiful Sunset In Flag Rock Recreation Area – October 27, 2017
Air temperatures reached 0 degrees Celsius ( 32 F ) at the summit level of the High Knob Massif prior to sunset Saturday, as rain and dense fog engulfed the high country. Cooling on upsloping NW-N winds taking air temps down quicker than aloft, where readings remained above freezing. Rainfall totals topped 1.50″ along the high country into Saturday evening.
European Model 500 MB Analysis At 8:00 AM Saturday – October 27, 2017
A deep air upper trough ( above ) digging southward into the eastern USA is trying to capture newly named Tropical Storm Philippe, and IF the timing had been only a little bit different a much bigger impact could result; however, such a setting as Superstorm Sandy is rare.
As it is, low pressure will develop east of the Appalachians and help pull cold air aloft over the mountains as a strong low-level NW-N upslope flow develops into Sunday.
European Model 850 MB Analysis At 8:00 AM Saturday – October 28, 2017
While cold air flooded into the mountains Saturday PM into Saturday Night, generating simply NASTY conditions as was expected, forecast models show that temps aloft do not cool enough to support snow until overnight into the morning hours of Sunday along the Cumberland-Allegheny fronts.
NAM 3 KM Model Forecast Snowfall Pattern
Forecast models struggle with amounts and almost always under-estimate snowfall within the High Knob Massif at the expense of very often over-estimating amounts modeled to fit the Eastern Continental Divide, as climatology-research well documents. The general pattern of NW-N upslope flow is correct; however, with leeward depletion.
Snowfall totals of more than 6″ will likely occur on some peaks, being most widespread and heaviest along the backbone of the Allegheny Front in central-northern West Virginia. Early in the snow season highest snow amounts are typically biased toward highest elevations and favored upslope zones to an even greater extent than they are during the winter months. Except for rare events, like Superstorm Sandy, early season snows during October are typically upper elevation favored ( average snowfall during October being just over 2″ at top of the High Knob high country ).
In this case, unseasonable cold will be the major factor for all locations ( from top to bottom ) through Sunday.
European Model 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 6-10
While cold air really grips much of Canada, the ensemble mean is showing a big warming trend with periods of wet conditions developing across the central-eastern USA during the first week of November.
ALERT For Strong Winds Developing Friday Night Into Saturday Morning At Mid-Upper Elevations Along The Cumberland Mountains
An increasing pressure gradient in advance of a strong cold front and the coldest air mass of this season will cause the development of strong winds at higher elevations in the Cumberland Mountains during Friday Night into Saturday. Caution is advised.
Potential For Accumulating Snow Increasing
A strong cold front and upper air trough is expected to transport unseasonably cold air southward into the mountains this weekend into the beginning of next week as bombogenesis occurs over the New England states. NW-N upslope flow will bring sticking snow into the eastern highlands of West Virginia, with the potential now increasing for accumulating snow farther south along the mountains to the High Knob Massif, Mount Rogers, Roan-Hump Mountain, into the top of the Great Smokies.
Overnight Into Friday Morning
Mostly clear ( a few high clouds ). SSW-SW winds 5-15 mph, with higher gusts, on mountain ridges & exposed plateaus below 2700 feet. SSW-SW winds 10-20 mph, with higher gusts, on upper elevation mountain ridges. Temps varying from upper 20s to mid 30s in valleys to 40s along exposed ridges & plateaus. Wind chills in the low-mid 30s along higher mountain ridges.
Friday Afternoon
Mostly sunny. Blue skies. Gusty winds. SSE-SSW winds at 5 to 15 mph, with higher gusts on mountain ridges. Temps varying from 50s at upper elevations to the mid-upper 60s.
Friday Night Into Saturday Morning
Increasing clouds with rain developing by morning. Windy. SSE-SSW winds increasing to 10-20 mph, with higher gusts, at elevations below 2700 feet. SSE to SW winds 20-30 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures falling into the 40s to lower 50s by morning. Wind chill factors in the 30s to lower 40s at upper elevations.
Saturday Morning Through The Afternoon
Rain. Local downpours. Turning colder. Winds shifting NW at 5 to 15 mph, with higher gusts, by mid to late afternoon. Temperatures dropping into the 30s to middle 40s ( coldest at higher elevations ). Low cloud bases with widespread dense fog across upper elevations. Nasty!
*The potential of the first accumulating snow is increasing for middle-upper elevations ( above 2000-3000+ feet ).
Saturday Night Into Sunday Morning
Cold & blustery with rain showers changing to snow showers and flurries. NW-NNW winds 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges and plateaus. Temperatures varying from the lower 20s to lower 30s ( coldest at highest elevations ). Milder south into river valleys of the Clinch, Powell, Holston drainages. Wind chills in the 10s & 20s, except dropping to around 10 degrees or lower on peaks above 3600 feet. Rime formation in the upper elevations above 3300 feet.
NOTE – A widespread freeze occurred into Thursday morning so I will no longer be highlighting any alerts related to frost-freezing conditions.
Weather Discussion ( Wintry Blast )
A drastic change in the weather is expected between a very nice TGIF ( outside of high country wind chills ) and a nasty Saturday into Sunday period.
Black Mountain Mesonet – 1 Hour Observations Ending At 12:20 AM Friday ( Oct 27 )
Changes related to this big weather shift are already being felt in upper elevations tonight, via gusty winds, with an initial sharp temperature drop in high valleys now being replaced by temp rises with recoupling of all but the most sheltered valley boundary layers.
European Model 850 MB-Surface Analysis At 8 AM Thursday – October 26, 2017
The first snowflakes of the season fell in the high country of the High Knob Massif during October 25 as the first of two cold pushes crossed the mountains ( the next one just emerging upstream near the Canadian border, above, will certainly be the most vigorous ).
Clearing skies into Thursday Morning ( October 26 ) allowed temps to drop into the 20s in many mountain valleys, with a hard freeze being observed in Clintwood, Norton, Tacoma-Coeburn and many other places ( coldest temps were recorded in high valleys above 3000 feet in the high country of the High Knob Massif ).
European 51-Member Ensemble Mean 500 MB Height Anomalies – 8 AM Oct 29
Details of the upcoming pattern are still being worked out by the models, but it is clear that a deep upper trough and disturbance will dig into the eastern USA into Sunday.
The first snow accumulations of the season look nearly certain now for higher elevations in the eastern highlands of central & northern West Virginia, with the only question being how far south along the Appalachians will this extend into Sunday.
Regardless of the snow potential, conditions will become increasingly NASTY as Saturday passes into Saturday Night and Sunday Morning with true winter temperatures and wind chills to impact the mountain region. Get Ready!
ALERT For Ponding Of Water Along Roadways And For Swift Water On Creeks Draining The High Country Of The High Knob Massif Into Monday Night
A general 2.50″ to 3.00″+ of rain has fallen from the City of Norton across the High Knob Massif, as well as into adjacent locations in the Clinch & Powell river valleys.
A Blast Of Cold Air Will Be Felt Tuesday Into Thursday AM With The Coldest Temperatures Of This Autumn At Highest Elevations ( Especially ).
Low wind chill values for this time of year are expected at upper elevations in the high country during Tuesday into Wednesday. Coldest valley temperatures may occur by Thursday AM, but will depend upon the timing of the next digging trough. Stay tuned.
Overnight Into Monday Morning
Increasing clouds. Chance of a shower by sunrise. Windy across middle-upper elevation mountain ridges-plateaus. SSE to S winds 10-20 mph, with higher gusts, along ridges-plateaus below 2700 feet. SSE to S winds 15-25 mph, with 30-50+ mph gusts, along mountain ridges above 2700 feet. Mild with temperatures widespread in the 50s to low 60s.
Monday Morning Through Monday Afternoon
Rain developing with a chance of thunderstorms. Downpours likely. Locally heavy rainfall totals, especially within upslope locations across the High Knob Massif and Tennessee Valley Divide. Windy. SSE winds shifting SW at 10-20 mph, with higher gusts, below 2700 feet. SSE to SW winds 20-30 mph, with higher gusts, above 2700 feet. Low cloud bases with dense fog across upper elevations. Temps dropping into the 50s lower-middle elevations, and into the 40s upper elevations, by mid-late afternoon.
Monday Night Into Tuesday Morning
Rain tapering to light rain. Partial clearing possible by morning. Chilly. SSW to SW winds at 10-20 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures varying from the mid 30s to lower 40s. Wind chill factors in the 20s highest elevations.
Tuesday Afternoon
Partly to mostly cloudy. Chance of rain showers. Chilly. SW-WSW winds 5-15 mph, with higher gusts. Temperatures varying from the low-mid 40s to the low-mid 50s ( coldest in upper elevations ), dropping by late afternoon. Wind chills in the 30s & 40s, except locally colder on highest peaks.
Tuesday Night Into Wednesday Morning
Partly cloudy. Cold. SW-W winds 5-10 mph, with higher gusts along mid-upper elevation mountain ridges. Temps varying from the mid-upper 20s to the lower-middle 30s, coldest in the upper elevations. Wind chills in the 20s and 30s, except dropping into the 10s at high elevations in the High Knob high country above 3300-3500 feet.
With blocking at high latitudes another deep upper air trough is expected to dig into the region by late week into this weekend of October 27-30. The will be monitored for the potential of the first accumulating snow in the mountains. Stay tuned for updates and changes that may diminish or enhance this potential.
Weather Discussion ( Colder Pattern )
A trend toward a much colder weather pattern is taking shape for the coming week. This transition will feature strong winds into Monday, with general strong speeds at upper elevations and local mountain wave winds in the favored breaking zones lee of the larger mountains.
Big Cherry Wetland Valley – October 21, 2017
An average nightly MIN of 28.2 degrees was recorded at Big Cherry Valley 4 in the High Knob Massif during October 17-21, with a total of 39.2 hours now being observed below freezing in October. Many trees on, and along, the high valley floor are now bare of leaves.
The potential for heavy rainfall, with at least a period featuring torrential downpours, along and ahead of a strong cold frontal zone of convergence, will be possible everywhere into mid-day to early afternoon Monday.
HRRR Model Future Doppler Forecast At 11:00 AM Monday – October 23, 2017
The heaviest rainfall, and highest totals in general, are expected in favored upslope zones where strong winds will help enhance orographics. This includes the eastern slopes of the Blue Ridge, as well as the High Knob Massif – Black Mountain corridor within the Cumberland Mountains.
HRRR Model Future Doppler Forecast At 1:00 PM Monday – October 23, 2017
Chilly air pours into the mountain region into Tuesday and Wednesday, with rather significant wind chills for this time of year within the high country of the High Knob Massif on gusty SSW-WSW winds.
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 1-5
This will mark the beginning of a much different pattern than experienced during most of October 2017, with much colder conditions ( in the mean ) expected throughout the next 10 days to close October and open November 2017.
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 6-10
While temperatures trend below average in the next few days, it is the extended 6-10 day period that has a notable potential to turn down-right wintry in the eastern USA.
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 1-5
Could this include the first accumulating snow of the season, at least in upper elevations ( if not lower ) on upsloping NW winds as a coastal storm develops?
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 6-10
It remains too early to know for certain; however, the trend and upper air pattern is supportive. Check back later as the details of this evolving pattern become more clear.
Mostly clear. Light winds ( mostly less than 10 mph on mid-upper elevation ridges ). Large vertical temperature spread between cold mountain valleys and milder, exposed ridges & plateaus. Temperatures varying from 20s to lower 30s in the colder valleys to the mid 40s to low 50s on exposed ridges and plateaus. Areas of river valley-lake fog.
Friday Afternoon
Mostly sunny ( some high clouds ) and mild. Light winds. Temperatures varying from middle-upper 60s in upper elevations to the lower-middle 70s.
Friday Night Into Saturday Morning
Mostly clear ( some high clouds ). Winds SSE-SSW at 5-10 mph, with some higher gusts, along mid-upper elevation mountain ridges. Large vertical temp spread between the colder valleys and exposed ridges-plateaus. Temperatures varying from 30s in mountain valleys to the low-mid 50s on exposed ridges & plateaus ( around or below freezing in the coldest valleys at upper elevations ). Areas of river valley fog near lakes and mainstem rivers.
Saturday Afternoon
Partly sunny ( high clouds ). Mild. SSE winds mostly less than 10 mph. Temperatures varying from 60s in upper elevations to the mid-upper 70s.
Saturday Night Into Sunday Morning
Partly cloudy ( high clouds ). Winds SSE-SSW at 10-20 mph, with some higher gusts, on mid-upper elevation mountain ridges & exposed plateaus. Temperatures varying from 30s to lower 40s in colder valleys, decoupled from any wind, to the 50s across exposed ridges-plateaus.
Sunday Afternoon
Partly sunny ( high clouds ). Winds SSE at 5-15 mph, with some higher gusts. Temperatures varying from 60s in the upper elevations to the low-mid 70s.
Soaking rain followed by a blast of cold air is expected by the early to middle portions of next week. The first flakes of snow will also be possible at highest elevations. Locations which have not yet dropped to freezing or below, will likely do so next week.
Weather Discussion ( Nice Pattern )
A nice weather pattern, dominated by High pressure, will rule the mountain landscape through this weekend before major changes occur next week.
Rugged Stone-Pickem Mountain of High Knob Massif – October 18, 2017
Hold out Northern Red Oaks ( variation borealis ) in parts of the upper elevations will be changing to join a more muted array of color ( with more brownish tones ) where trees are not already bare. Meanwhile, lower elevations will have a chance to reach some sort of “peak” in a rather disjointed color season across the eastern USA.
Black Mountain Mesonet Observations – Ending At 12:15 AM Friday ( October 20 )
Although mountain ridges remain relatively mild, the bottom has been dropping out of the temperature in high valleys of the High Knob high country during recent nights with very dry air and light winds.
*Some middle elevation thermal belt sites, such as Nora 4 SSE on the Long Ridge of Sandy Ridge, have only dropped to 39 degrees during October to contrast with middle 20s in high valleys and a minimum of 31.6 degrees in Clintwood ( in the low elevations ).
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 6-10
A major pattern change across North America has been well forecast by the European ensembles to occur next week.
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 6-10
This will include a wetter and colder transition as high latitude blocking develops near Greenland ( recurvature of a western Pacific typhoon will be beginning this process ).
Typhoon Lan In The Western Pacific at 0620z – October 20, 2017
