ALERT For Strong Wind Gusts & Heavy Rainfall Developing Into The Overnight-Wednesday AM
Strong rises along creeks & streams will be possible along the Cumberland Mountains & Cumberland Plateaus into Wednesday with developing showers & embedded thunderstorms. Locally strong to severe wind gusts, with downward transfer of high momentum air aloft, will also be possible.
Remain alert for ponding of water along roadways and in low-lying, poor drainage areas. Some drains could be stopped up by leaves, with no major rains observed since mid-September.
Tune Into NOAA Weather Radio And Your Favorite Media Sources For National Weather Service Watches, Warnings & Advisories.
Tuesday Evening Into Wednesday Morning
Increasing clouds with showers and thunderstorms developing into the overnight-morning. Locally heavy rainfall. SSE-SSW winds increasing to 10-20 mph, with higher gusts, below 2700 feet. SSW-SW winds 20-30 mph, with higher gusts, along mountain ridges above 2700 feet. Evening temperature dropping into the upper 30s to low 40s in sheltered valleys, then rising in the overnight into the 50s. Otherwise, temps in the upper 40s to middle 50s.
Wednesday Afternoon
Rain & showers diminishing during mid-late afternoon. Windy. SW winds 15-25 mph, with higher gusts. Temps in the 50s to lower 60s, dropping during late afternoon into the 40s to lower 50s.
Wednesday Night Into Thursday Morning
Cloudy and chilly. Gusty. A chance of drizzle or high elevation sleet pellets and flurries. WSW winds 10-20 mph, with higher gusts. Temperatures varying from upper 20s to the mid-upper 30s. Wind chills in the 10s and 20s ( coldest at the highest elevations ).
Thursday Afternoon
Partly cloudy. Seasonally cold. Winds WSW-WNW at 5-15 mph, with higher gusts. Temperatures varying from low-mid 30s in upper elevations to the low-middle 40s. Wind chills in the 20s and 30s ( coldest at highest elevations ).
Weather Discussion ( Heavy Rainfall )
An outbreak of strong-severe thunderstorms over the Dixie States will spread heavy rain northeast to the Appalachians overnight into Wednesday morning. Although storms will tend to weaken, locally strong-severe wind gusts could remain possible in stronger activity.
HRRR Model Total Rainfall Forecast Up To 9:00 AM Wednesday
The Storm Prediction Center maintains a Marginal Risk for severe thunderstorms ( main threat being wind damage ).
Storm Prediction Center Outlook For Wednesday
Otherwise, an increasing pressure gradient will strengthen winds into the overnight-Wednesday and help orographic forcing for rainfall.
HRRR Model Temperature Forecast At 9:00 AM Wednesday – November 30
Winds will continue to be gusty into Wednesday Night and Thursday Morning as the mild air gives way to much colder air to the west behind this wave of rain and storms.
A couple more storm systems are on tap by this weekend and/or next week, with significant precipitation. Ensembles currently being split on timing of the next system by this weekend. Arctic air will also begin to make a move south into the USA next week. Stay tuned for updates as details become more clear.
ALERT For High ( ROARING ) SSE-SSW Winds Monday Into Monday Night. Wind Gusts Of 40-60+ MPH Will Become Likely By Late Monday. Caution Is Advised.
Tune Into NOAA Weather Radio And Your Favorite Media Sources For National Weather Service Watches, Warnings & Advisories.
Another period of STRONG winds will become likely Tuesday Night Into Wednesday. Check back for updates.
Rainfall amounts by late Wednesday Into Thursday ( November 30 to December 1 ) could be enough to cause strong rises along creeks and streams, with enhancement expected to be greatest in favored orographic forcing zones along the Cumberland Mountains and the adjoining Cumberland Plateau into Tennessee ( esp. Wednesday ).
Overnight Into Sunday Morning
Mostly clear. Cold. Winds becoming light & variable, except along upper elevation mountain ridges where WSW-WNW winds of 5-10 mph will occur. Temperatures varying from the 10s to mid 20s ( 10-15 in colder valleys versus steady or slowing rising temperatures along highest ridges into the 30s overnight into morning ).
Sunday Afternoon
Partly-mostly sunny ( high clouds ). Milder. Light SSW-SW winds increasing to 5-15 mph by sunset. Temps from the mid-upper 40s to the mid-upper 50s ( coolest at highest elevations ).
Sunday Night Into Monday Morning
Increasing mid-high altitude clouds. S winds 5-15 mph, with higher gusts, along mountain ridges below 2700 feet. Winds SSW-SW 10-20 mph, with higher gusts, along upper elevation mountain ridges. Temperatures varying from the upper 20s to lower 30s in colder valleys to the mid-upper 40s along exposed mountain ridges ( wind chills in the 20s and 30s on ridges ).
Monday Afternoon
Mostly cloudy. Becoming windy. SSE winds 15-25 mph, with higher gusts, below 2700 feet. Winds SSE to S 25-35 mph, with higher gusts, on mountain ridges above 2700 feet. Winds could gust over 50 mph at high elevations and with any mountain waves that develop. Temperatures varying from 40s in the upper elevations to the 50s at lower-middle elevations.
Monday Night Into Tuesday Morning
Cloud bases lowering-thickening with rain developing. Periods of locally heavy rain possible. Windy. Winds SSE-S at 20-40 mph, with higher gusts, shifting SW by morning. Temperatures steady or slowing rising in the 50s. Winds could gust over 50 mph at high elevations and with any mountain waves that may develop ( esp. Monday Night ).
A second wave of heavier rainfall is currently expected to impact the mountain area on Wednesday. Rainfall amounts may need to be closely followed, with strong rises possible along streams. Stay tuned for later updates on this heavy rainfall potential.
Weather Discussion ( Significant Rain )
Sunday Evening Update
NAM 12 KM Model Total Rainfall Forecast – Sunday Morning Run
While there remains some run-to-run differences on rainfall amounts, models have settled on a significant rainfall event during the Tuesday-Wednesday period.
NAM 12 KM Model Total Rainfall Forecast – Sunday Evening Run
Orographic forcing will enhance amounts in favored places, such as the High Knob Massif where forecast trajectories are close to the long-term MEAN climatological air flow within the 925-850 MB zone ( esp. into Wednesday ).
*Although some models are splitting rainfall nearly evenly between the two waves, the second wave is likely to be most productive given that the atmosphere will ( by then ) be wet, saturated in nature and more unstable than initially.
Previous Discussion
Although Saturday temperatures struggled to break the freezing point at high elevations in the High Knob Massif, following morning riming on high peaks, the air mass will be changing in coming days as temperatures-dewpoints rise in advance of a couple waves of significant rainfall.
NW Flow Mountain Waves – November 26, 2016
Air rises and the cloud thickens amid the ridge of each wave, while the cloud thins as air sinks into the trough of each wave ( think of oceans waves, except these are flowing through the fluid atmosphere ).
NW Flow mountain waves were prolific on Saturday, before moisture decreased by later in the day, with a couple dozen or more being counted on NASA visible imagery across the main generation zone from the VA-KY border to the TN-NC border.
Meanwhile, with clear skies and decoupled winds many mountain valleys will drop into the 10s by Sunday morning, with coldest valleys already in the 10s as of Midnight. This is in contrast to temperatures which are rising into the 30s along higher mountain ridges ( from evening 20s ).
NAM 12 KM Model Total Rainfall Forecast Up To 7 AM Wednesday ( Nov 30 )
The main story this week will be the shift into a wet pattern that brings a couple waves of significant rainfall. Heaviest rains are expected on Wednesday, just beyond the time of the above graphic. It will be important to tune back in as this event comes into range of short-range models.
The European Model and its Ensemble MEAN has been very consistent in showing the heaviest wave of rain developing Wednesday into early Thursday, boosting totals. Although precipitation spreads are large, varying from just under 1.00″ upward to 6.00″ on the 51-Members at the Wise ( KLNP ) gridpoint, the MEAN is around 2.00″ to imply that local amounts will be greater ( as also is well supported by local climatology ).
The development of ROARING SSE-SSW winds later Monday into early Tuesday will signal the upcoming rain event.
ALERT For Dense Fog & Freezing Fog Across Upper Elevations Above 3000 Feet Into Saturday Morning. Locally Lower Bases In Places Along & N to NW From The High Knob Massif and Tennessee Valley Divide.
As of 10:00 PM Friday air temperatures had dropped to freezing ( 32 F ) on the highest peaks, with low cloud bases producing dense fog at elevations above 3000 feet. The freezing fog level will drop toward 3000 feet overnight, with very low visibilities at times. Some freezing drizzle and/or drizzle will be possible into Saturday morning.
A Drop In Cloud Bases Is Being Monitored For Later Friday Into Saturday Morning On Upsloping NNW-NW Winds, with Freezing Fog Possible At Higher Elevations Above 3000-3300 Feet Along & North Of The High Knob Massif-Tennessee Valley Divide.
Overnight Into Black Friday Morning
Partly to mostly cloudy. Areas of fog. S-SW winds 5-15 mph with higher gusts ( especially along upper elevation ridges ). Temperatures varying from 30s in mountain valleys to the 40s across exposed mid-upper elevation ridges. Wind chills in the 30s along high ridges.
Friday Afternoon
Mostly cloudy. Turning cooler. Chance of sprinkles or light rain showers & drizzle. N-NW winds 5-15 mph, with higher gusts on ridges. Temperatures varying from the mid 40s to the mid 50s ( coolest at high elevations ). Wind chills in the 30s and 40s ( coldest at highest elevations ).
Friday Night Into Saturday Morning
Cloudy. Turning colder. Low clouds with dense fog across higher ridges becoming freezing fog. Winds NNW to NW at 5-15 mph. Temperatures varying from low 20s to lower 30s ( around 20 on highest peaks ). Wind chills in the 10s & 20s.
Saturday Afternoon
Low clouds giving way to partly-mostly cloudy skies. Winds NW-N at 5-10 mph. Temperatures varying from 30s to low 40s ( around 30 degrees at highest elevations ). Winds chills in the 20s & 30s ( around 20 degrees on highest peaks ).
Saturday Night Into Sunday Morning
Mostly clear. Cold. Winds becoming light & variable, except along upper elevation mountain ridges where NW winds of 5-10 mph will occur. Temperatures varying from the 10s to mid 20s ( 10-15 in colder valleys versus steady or slowing rising temperatures along highest ridges into the 30s overnight into morning ).
Weather Discussion ( Wet Pattern )
Friday Night Update
A developing inversion below 850 MB is combining with cold air advection on upsloping NNW-NW winds to develop dense fog at high elevations along the Cumberlands.
Black Mountain MesoNET – Observations Ending At 10:40 PM Friday
Friday evening visibility has been very low on Eagle Knob of the High Knob Massif, with cloud bases having dropped downward to around 3100 feet in elevation as of 9:45 PM.
Freezing fog developing at highest elevations will drop into the overnight toward 3000 feet and could locally get a little lower along & north to northwest of the High Knob Massif. Some freezing drizzle ( or just drizzle at lower elevations ) will also be possible into Saturday morning.
Cloud bases will lift into Saturday afternoon, but much of the day could remain cloudy along the upslope side of the mountains ( keeping conditions raw and cold ).
Previous Discussion
Smoky conditions again became a significant issue across the region on Wednesday, with lingering Thanksgiving day smoke beneath partly-mostly cloudy skies.
Smoky Morning Sunrise Above Long Ridge of Tennessee Valley Divide
Wayne Riner Photograph Thoughts: Wildfires filled the morning sky with smoke, turning the sun red and blurry.
Black Mountain MesoNET
Thanksgiving day MAXS reached around 50 degrees at highest elevations ( versus 60-65 at lower elevations ) with dense fog and low cloud bases obscuring high crest lines during much of the day. Rainfall only totaled around 0.05″ at Big Cherry Lake Dam.
A wind shift Friday, with development of N-NW flow, will again push away the smoke and turn air chilly in the Cumberland Mountains.
NAM Model Forecast Sounding At 7 AM Saturday – November 26, 2016
Clouds and the potential for some freezing fog at high elevations is being watched for late Friday into Saturday morning and will be dependent upon the transport of low-level moisture into the area. A low-level inversion could alter this, so stay tuned for updates.
There appears to be more uncertainty in the short-term, with fine details, than in the big picture of the longer term which looks to turn wet across the Mountain Empire.
European Ensemble MEAN 500 MB Height Anomalies – DAYS 4 to 8
There have been no changes in my previous thinking, with model ensemble groups actually becoming stronger and in better agreement with a flow pattern conducive to a shift into wetness across the Mountain Empire next week.
The European Ensemble MEAN basin average rainfall is around 1.50″ during the next 7 days, with 2.50″ to 3.00″+ during the next 14 days ( which means the potential for locally heavier amounts ).
A deepening southwesterly flow, with a tap into Gulf of Mexico moisture ( a lacking ingredient in recent months ), will be a key factor in this shift to wetness.
GFS 21-Member Ensemble Precipitation Forecast – Next 12 DAYS
Rainfall can not be truly counted, of course, until it becomes measured in the rain gauge…but certainly the upcoming pattern offers much hope and represents a radical shift from Autumn 2016.
Clear & cold. WNW-NW winds 5-15 mph, with higher gusts, along middle elevation ridges and plateaus below 2700 feet. Winds NW at 10 to 20 mph, with higher gusts, on mountain ridges above 3000 feet. Temperatures in the 10s to mid 20s, coldest in sheltered valleys and along highest ridges. Wind chills 0 to 10 degrees on exposed ridges in upper elevations to the 10s and lower 20s.
Monday Afternoon
Mostly sunny. Continued chilly. NW winds 5-15 mph, with higher gusts. Temperatures varying from upper 20s to low 30s in upper elevations to the upper 30s to lower 40s.
Monday Night Into Tuesday Morning
Becoming partly cloudy ( high clouds ). Winds NW-N 5-10 mph, with higher gusts, on mid-upper elevation mountain ridges. Temperatures varying from 10 to 15 degrees in the colder valleys ( locally even colder ) to middle 20s to lower 30s ( warmest on exposed ridges where temps will be near steady or slowly rising ).
Tuesday Afternoon
Partly-mostly sunny ( high clouds ). Light & variable winds. Near inversional conditions developing with temperatures varying in the upper 30s to upper 40s ( some valleys being nearly as cool or cooler than adjacent ridges ). Milder in some spots, especially into the Great Valley.
Tuesday Night Into Wednesday Morning
Increasing clouds into the overnight-morning. Winds S-SW at 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures varying from 20s in colder valleys to the mid 30s to low-mid 40s on exposed ridges.
Weather Discussion ( Chilly )
Monday PM Update
High Knob Massif Webcam – University Of Virginia’s College At Wise
My afternoon update is to zero in better on MIN temps tonight with 10 to 15 degrees expected in colder valleys to contrast with milder readings on exposed ridges ( no place; however, will feel mild ). Local MINS may actually dip just below 10 degrees in coldest upper elevation valley spots if high altitude clouds do not thicken into the overnight.
*The coldest MIN temperature recorded in high valleys so far this autumn has been 8 degrees on the morning of November 13.
NASA Visible Image On Monday – November 21, 2016
I took a NASA visible image today to illustrate how close sticking snow came to the NW upslope flow corridor of the Mountain Empire, highlighting the sprawling High Knob Massif and Mount Rogers for reference points. Smoke plumes from the larger fires remain visible as well.
Previous Discussion
Following the first widespread snowflakes, sleet pellets, and a bit of riming at highest elevations, the air mass is seasonally chilly. Although winds remain gusty on high ridges, deep valleys have decoupled ( winds calmed ) to allow sheltered valleys & hollows to join high ridges as coldest places into Monday morning ( locations between these extremes, in thermal belts, being “milder” ).
*The above being especially true for the Russell Fork & Levisa Fork basins, and locally in the Upper Tennessee Basin, where terrain is highly dissected. Cross-barrier speed up flow will prevent this for mostly all locations along the eastern slopes ( Blue Ridge ) where turbulent mixing will be enhanced into Monday morning.
Black Mountain MesoNET Observations
Wind chills Sunday evening have occasionally dipped to between 0 and 5 degrees along highest ridges with air temperatures around 20 degrees. This is part of a sub-freezing period that will last into Tuesday in some places amid upper elevations of the High Knob Massif ( the longest sub-freezing period since last winter ).
With low sun angles it is getting that time of year in the mountains where temperature inversions by day, not just during night, become possible at times. Tuesday will offer conditions at least favoring near inversional temps with some hollows-valleys being nearly as cool, or locally cooler, than adjacent ridges ( temperatures typically decrease with increasing elevation during day-time hours, with opposite or inversional conditions often being common at night ).
European Ensembles MEAN 500 MB Height Anomalies Forecast – DAYS 6 to 10
Finally I can say that I really like the look of the extended period upcoming during the next 1 to 2+ weeks, with rising pressures across the Arctic Basin and decreasing heights and pressures over Middle Latitudes that will be working together with a southward developing baroclinic ( temp ) zone to push the MEAN jet stream and storm track south.
While a mid-November change in the pattern has occurred, as I had been expecting for some time, everyone knows that what we are really seeking is precipitation to ease forest fire conditions and help depleted mountain lake water supplies. This pattern is going to now make that possible as it continues to evolve during the remainder of November into early December. Finally!
European Model Mean Sea Level Forecast At 7 AM on November 30, 2016
The above forecast chart at DAY 10 is certain to change, but the synoptic-scale trend is very clear with a much better setting for precipitation events ( both in the frequency of their occurrences and in amounts ) as November wanes and December arrives. This shows up well, with highest confidence, on MEAN ensemble charts such as that of the 51-Member European group.
This means increased chances for needed precipitation with a strong signal for another major storm system showing up by the end of November. The difference this time, with a southward suppressed jet stream, being the chance to tap Gulf of Mexico moisture for enhanced precipitation totals.
Although this most recent event was by no means a drought buster or even a good dent maker, the general 0.30″ of precipitation that was received in the High Knob Massif area was more than models forecast. I expect this trend to continue as more and more events develop winds that push against the mountain terrain, cranking up the orographic forcing which helps make the massif area the wettest in Virginia over the long-term.
GFS Ensemble Total Precipitation Forecast – Next 16 Days
The 21-Member GFS ( USA ) Model ensemble group shows the basic agreement in increasing precipitation amounts across the eastern USA during the next couple of weeks. Most importantly, the much more stable and reliable 51-Member European group supports this trend. In addition, the Canadian Ensembles as well as the Japanese ( JMA ) Model are also on board. Details of specific events, of course, to be worked out as time passes.
I do not go by any single model, but instead like to use ensembles and their MEANS ( especially the European ), with currently very good agreement among global model ensemble groups about this increasing precipitation trend.
*I am not legally allowed to show ( display ) the European Model or its Ensembles precipitation graphics, only the most basic charts from it.
A sharp temperature drop will occur between the predawn to sunset period of Saturday, with falling temperatures combining with gusty WNW winds to generate bone-chilling conditions. Flurries and snow showers will be likely Saturday Night into Sunday AM, with a dusting up to 1″ possible along the upslope side of the mountains ( with riming at highest elevations ).
Caution advised for those hunting and/or outdoors this weekend given this is the first wintry blast of the season ( it will feel very cold ). A few slick places, or even sections, could develop on roads ( especially in favored upslope locations at higher elevations ) Saturday Night into Sunday Morning.
Relative humidity will remain moderate-high along the upslope side of the mountains during the weekend, before sharp drops in values occur into early next week ( especially in upper elevations ).
Overnight Into Saturday Morning
Mostly clear early with increasing clouds and developing rain showers by morning. Becoming windy. SSW-SW winds increasing to 10-20 mph, with higher gusts, below 2700 feet by morning. SW winds at 15-25 mph, with higher gusts, on middle-upper elevation mountain ridges above 2700 feet. A large vertical evening temperature spread forming between colder valleys and breezy-gusty ridges, then temps rising in valleys overnight into morning ( falling on high ridges into morning ). Evening temps falling into 30s & 40s in valleys versus 50s-lower 60s on ridges. High ridges dropping rapidly to around 40 degrees by morning.
Saturday Morning Into Saturday Afternoon
Turning sharply colder. Morning rain showers changing to snow showers in the mid-upper elevations. Windy. W-NW winds 10-25 mph, with higher gusts. Temperatures falling into the 30s at middle-lower elevations, and into the 20s at upper elevations, in locations along & north-northwest of the High Knob Massif and Tennessee Valley Divide. Wind chills dropping into the 10s and 20s ( except single digits possible on highest peaks above 3500 feet by afternoon ).
Saturday Night Into Sunday Morning
Chance of flurries & snow showers along the upslope side of the mountains. Cold & windy. WNW to NW winds at 10-25 mph, with higher gusts. Temperatures dropping into the middle 10s to mid 20s ( coldest at the highest elevations ). Wind chills varying from -5 below to 5 above zero at highest elevations, in gusts, to the 10s in lower-middle elevations.
Sunday Afternoon
Becoming partly-mostly sunny. Cold. WNW-NW winds 10-20 mph, with higher gusts. Temperatures varying from the low-mid 20s in upper elevations to the low-mid 30s ( milder south into the Great Valley ).
Sunday Night Into Monday Morning
Clear & cold. WNW-NW winds 5-15 mph, with higher gusts, along middle elevation ridges and plateaus below 2700 feet. Winds NW at 10-20 mph, with higher gusts, on mountain ridges above 2700 feet. Temperatures in the 10s to mid 20s, near steady or slowly rising overnight at highest elevations.
Weather Discussion ( Cold Blast )
Saturday Afternoon Update
Official precipitation totals up to around 4:00 PM included 0.22″ on the campus of the University Of Virginia’s College At Wise and 0.30″ at the City of Norton Water Plant.
Snow flurries and occasional pellets of sleet fell in Norton-Wise all afternoon. Trees at the summit of High Knob had a light, visible coat of rime as late afternoon clouds lifted just enough to see the crest lines.
Saturday Morning Update
I have updated my forecast to take out the likely wording and to just have a change to snow showers in mid-upper elevations ( this may also include some lower elevations along-north of the High Knob Massif-TN Valley Divide ).
High Knob Massif Webcam – University Of Virginia’s College At Wise
Some flakes are already falling in Wise and a little is actually beginning to stick at the summit level of the High Knob Massif where temps have dropped into the 20s as of 10:00 to 10:30 AM. Wind chills are already running as low as 10 to 15 degrees up top.
This cold followed around 0.30″ of rain at the summit level.
This cold blast means business, even though total accumulations will be limited across the area. Reference my previous discussion.
Previous Update
The first true blast of winter conditions will make even the most hardy shiver by later Saturday into Sunday morning.
High Knob Massif MesoNET – Eagle Knob
This will be especially true since even highest elevations climbed into the 60s during Friday afternoon.
Black Mountain MesoNET – Ending At 12:30 AM on Saturday ( November 19 )
Wind speeds are increasing across higher elevations within the Cumberland Mountains as a large vertical temperature spread ( 20 to 30 degrees ) has now formed between colder valleys ( in the 30s ) versus milder, increasingly windy ridges ( in the 50s & 60s ) as I had forecast.
*These temperature differences will tend to narrow into morning as vertical mixing increases and causes locally dramatic valley temperature jumps as high ridges ( which are holding steady ) begin to tumble by around sunrise.
While this will not be the significant precipitation event hoped for, it will be beneficial in terms of adding some wetness and increasing RH values. This will be especially true along the upslope side of the mountains where rain showers, snow showers, low cloud bases and riming ( at highest elevations ) on WNW-NW flow will combine.
NAM 12 KM Model 10 Meter Wind Streamlines & MSLP at 7 PM Saturday
Low-level moisture, in lowest levels of the atmosphere, will be limited with only extreme northern portions of West Virginia, northeastward along the Appalachians, receiving Great Lake moisture advection ( transport ) near the surface.
Due to friction within the planetary boundary layer ( PBL ), the flow turns across the surface isobars as roughly depicted by wind streamlines ( above & below graphics ) such that transport of moisture will be more west to west-northwest downstream of the Great Lakes. This causes the southern Appalachians to miss out, with flow from mid-continent, on this moisture.
NAM 12 KM Model 10 Meter Wind Streamlines & MSLP at 7 AM Sunday
Going above the surface layer, into the 950 to 850 MB zone, there will be some flow across the Great Lakes that reaches into the southern Appalachians ( especially for locations northeast of the Smokies from Lake Michigan ).
NAM 12 KM Model 850 MB Vorticity & Wind Vectors at 7 AM Sunday
Given very cold air and strong forcing ( torque forces ) this should be enough to at least generate the first widespread flurries and snow showers of the season, with a dusting up to around 1″ of accumulation ( perhaps locally more ) being possible along the windward side of the mountain chain, especially amid favored locations such as the High Knob Massif, Mount Rogers-Whitetop, Roan Mountain, and the Brumley-Beartowns of Clinch Mountain ( to note a few ).
The Bottom Line…A very cold weekend is upcoming with big stories being how COLD it will feel, the first widespread flakes, and the continued lack of a needed significant precipitation event. This is; however, part of a changing pattern that will feature more chances for precipitation in days and weeks ahead. Drought does not strike all at once, so in most cases it takes time to reduce and end its impact ( southwestern VA being amid a short-term drought versus locations to the south where much of 2016 has been dry ).
Forest fire conditions will worsen as the pressure gradient increases in advance of a cold front by late Thursday Night into Friday Night, before easing with increasing moisture, rising RH-cold air, this weekend.
A sharp temperature change will occur between Friday Night and Saturday afternoon-evening, with falling temperatures during the day Saturday ( and much colder wind chill factors ). Flurries and snow showers will be possible Saturday Night into Sunday, especially along the upslope side of the mountains.
Overnight Into Thursday Morning
Mostly clear. Light winds except NW at 5-10 mph along upper elevation ridges. Large vertical temp spread from frosty valleys to exposed ridges. Temps varying from the 20s in colder valleys to the low-mid 40s on exposed ridges.
Thursday Afternoon
Mostly sunny. Mild. Winds SSW-WSW generally less than 10 mph. Temperatures varying from upper 50s to lower 60s in upper elevations to the middle 60s to around 70 degrees ( warmer south into the Great Valley ).
Thursday Night Into Friday Morning
Mostly clear. Large vertical temperature spread forming between colder valleys and mild ridges. SSW to WSW winds 5 to 15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures varying from 20s to mid 30s in colder valleys to the upper 40s to mid 50s on ridges.
Friday Afternoon
Mostly sunny. Unseasonably warm. SSW-SW winds 5-15 mph, with higher gusts. Temperatures varying from lower-middle 60s in upper elevations to the upper 60s to lower 70s ( warmer south into the Great Valley ).
Friday Night Into Saturday Morning
Mostly clear early with increasing clouds and developing rain showers by morning. Becoming windy. SSW-SW winds increasing to 10-20 mph, with higher gusts, below 2700 feet by morning. SW winds at 15-25 mph, with higher gusts, on middle-upper elevation mountain ridges above 2700 feet. A large vertical evening temperature spread forming between colder valleys and breezy-gusty ridges, then temps rising in valleys overnight into morning ( falling on high ridges into morning ). Evening temps falling into 30s & 40s in valleys versus 50s-lower 60s on ridges. High ridges dropping rapidly to around 40 degrees by morning.
Saturday Morning Into Saturday Afternoon
Turning sharply colder. Morning rain showers possibly mixing with or changing to snow in upper elevations before ending. Windy. W-NW winds 10-25 mph, with higher gusts. Temperatures falling into the 30s by afternoon at middle-lower elevations, and into the 20s at upper elevations, in locations along & north-northwest of the High Knob Massif and Tennessee Valley Divide. Wind chills dropping into the 10s and 20s ( except some single digits possible on highest peaks above 3500 feet ).
Flurries & snow showers will be likely Saturday Night Into Sunday along the upslope side of the mountains, with light accumulations ( up to 1″ possible at highest elevations ). Formation of rime along the highest ridges and peaks ( above 3500 ft ) is expected.
*Note To Hunters: A prolonged period of sub-freezing conditions will occur from mid-morning Saturday into Monday above 3000 feet in the High Knob Massif. Bitter wind chill factors will also accompany the cold from Saturday into Sunday, especially on mountain ridges. Some slick stretches will be possible on roads within highest elevations as well.
Weather Discussion ( Wintry Blast )
The first blast of true winter air will strike Saturday with plunging temperatures and wind chills behind a cold front that passes early in the morning.
Forest Fire In SE Kentucky – Viewed From Pine Mountain In Dickenson County
Worsening fire conditions will have to be respected in advance of this cold front during Friday into Friday Night as winds increase with a strengthening pressure gradient. Smoke from many large fires burning across the southern Blue Ridge into the Cumberland Plateau may increase as winds shift S-SW in advance of this front.
NAM 12 KM Model Total Precipitation Forecast
Significant precipitation has never been expected with this event across the southern Appalachians, and latest model runs continue to confirm this with a weakening trend in precipitation amounts from west to east ( with little to nothing reaching east of the mountains ).
NAM 12 KM Model 850 MB Wind & Vorticity Forecast – 7 AM Sunday
It is hoped that enough moisture will be tapped from the Great Lakes to carry some into the southern Appalachians, with models suggesting best chances being northeast of the Great Smokies during Saturday Night into Sunday ( forcing from orographics will be moderate-strong with moisture seen as the limiting factor at this point ).
Some riming and light snow will be possible along windward slopes and crest lines in the High Knob Massif and Mount Rogers-Whitetop areas, with more significant snow accumulations to the northeast atop the eastern highlands of central-northern West Virginia. A small southward shift of air flow trajectories could change this, so be sure to check back for updates to see if local amounts may be greater than currently suggested by models.
As might be expected, the Great Lakes have unseasonably warm water for this time of year so if the vertical temp gradient can generate more mixing than models perceive ( via cold air moving over warm water ) then down-stream amounts could be greater than indicated in upslope locations.
Forest fire conditions will worsen as the pressure gradient increases in advance of a cold front by late Thursday into Friday, before easing with increasing moisture, rising RH and cold air, this weekend.
Overnight Into Tuesday Morning
Mostly clear. Cold. Winds W-NW at 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temps varying from 18-25 degrees in colder valleys to the mid-upper 30s to lower 40s along exposed ridges.
Tuesday Afternoon
Partly-mostly cloudy. Winds WSW-WNW 5-10 mph. Temps varying from middle-upper 40s at highest elevations to the middle to upper 50s ( warmer south into the Great Valley ).
Tuesday Night Into Wednesday Morning
Partly-mostly cloudy. Winds westerly at 5-10 mph, with higher gusts, along mid-upper elevation ridges. Temps varying from 30s in colder valleys to the low-mid 40s.
Wednesday Afternoon
Partly-mostly sunny. W-NW winds 5-10 mph, with some higher gusts. Temperatures varying from upper 40s to lower 50s in upper elevations to the upper 50s to low 60s.
Wednesday Night Into Thursday Morning
Mostly clear. Light winds except NW at 5-10 mph along upper elevation ridges. Large vertical temp spread from frosty valleys to exposed ridges. Temps varying from the 20s in colder valleys to the low-mid 40s on exposed ridges.
The first significant blast of wintry weather is being monitored for this weekend, with upsloping NW winds and the potential for rain showers to change to snow. Accumulating snow may occur at high elevations. Stay tuned for later updates on this developing blast of cold conditions.
Weather Discussion ( Weekend Blast )
The main focus this week is on development of the first major winter storm of the 2016-17 season in the lee of the Rockies, with a track northeast toward the upper Lakes.
Looking Toward High Knob Massif Along Horizon – Birch Knob of Pine Mountain
Some leaves and autumn color remain visible across lower-middle elevations to illustrate the anomalous nature of Autumn 2016 in the mountains. Frosty cold nights during this past week show; however, that the pattern is changing, albeit slowly for those fighting wild fires across the region.
My confidence is high that this weekend through the remainder of November will begin to generate conditions that will help ease the wild fire situation, and dryness of the surfaces. It begins with formation of the first major winter storm of this season in lee of the Rockies.
European Model MSLP and 850 MB Forecast At 7 AM Thursday – November 17
Although moisture transport into the warm sector is not forecast to be what we really want, some rain will become likely as the storm deepens and generates a strong pressure gradient. Initially, this will cause worse fire conditions in advance of the rain Thursday Night and Friday.
European Model MSLP and 850 MB Forecast At 7 PM Sunday – November 20
Rain showers will become likely into early Saturday with a rush of cold air following by late Saturday into Sunday and Monday. A flow across the Great Lakes will carry moisture south into the windward slopes of the Appalachians, with snow becoming possible ( likely at high elevations ).
How much moisture reaches the southern Appalachians will depend upon the flow and that will in part be determined by low pressure formation over the Northeastern USA by this weekend. Significant snow accumulations will be most likely along the eastern West Virginia highlands. Stay tuned for later updates on this developing winter blast.
Partly-mostly cloudy. Colder. Winds N-NE 5-15 mph, with higher gusts. Temperatures falling into the upper 20s to mid 30s, coldest at highest elevations & in colder valleys.
Saturday Afternoon
Sunny. Crisp. Light winds mostly less than 10 mph. Temperatures varying from upper 30s to lower 40s in upper elevations to the upper 40s to lower 50s.
Saturday Night Into Sunday Morning
Clear & cold. Hard freeze. Light winds. Temperatures varying from 10s in colder mountain valleys to the mid-upper 20s, except 30s on some exposed upper elevation mountain ridges.
Sunday Afternoon
Mostly sunny early with increasing clouds late. Light and variable winds. Temperatures varying from mid-upper 40s in upper elevations to the middle 50s to around 60 degrees.
Sunday Night Into Monday Morning
Partly-mostly cloudy. Light winds. Temperatures varying from 20s to lower 30s in coldest valleys to the 40s along exposed mid-upper elevation mountain ridges.
Monday Afternoon
Mostly cloudy. Small chance of sprinkles or light showers. Light northerly winds. Temperatures varying from 40s at upper elevations to the 50s at low-middle elevations in and north of the High Knob Massif & Tennessee Valley Divide.
A changing flow pattern across North America is underway with increasing shots of chilly air, interrupted by milder periods. The potential for the coldest air of the season, with possible wintry precipitation, is being monitored for the 7-10 day forecast period leading up to Thanksgiving week ( Nov 19-22 interval ). Please check back for later updates on this changing pattern.
Weather Discussion ( Seasonable Cold )
Slowly but surely the weather pattern is starting to change, as you will be able to feel this weekend as cold air grips the mountain landscape ( near to a little below average for this time of year, and certainly different from previous weeks ).
GFS Model MIN Temperature Forecast By Sunday Morning ( November 13 )
A widespread freeze is expected Saturday Night into Sunday Morning with 10s and 20s across the area ( 10s in colder valleys where some 10s have already been observed in high valleys ).
Note that due to dry ground and very low dewpoint air in the 900 to 800 MB layer that MIN temperatures along the mountains will tend to be colder than MOS & models are predicting ( as has been observed already this month ).
NAM 12 KM Model Total Precipitation Forecast Next 84-Hours
By early next week a system developing mostly east of the Appalachians will bring a chance for some precipitation, with the NAM Model group most aggressive in spreading some across the mountain chain.
The 51-Member European Ensembles also forecast some light amounts, but clearly place the emphasis of significant rainfall along the coastal Carolina’s ( a little more inland than predicted by the GFS Model below ).
GFS Model Total Precipitation Forecast Next 84-Hours
Although a drought easing rainfall is not yet in the forecast, the good news is that with a changing pattern opportunities for precipitation will be increasing during the remainder of November into the holiday period.
Light rain & showers. Turning chilly. Winds shifting NW at 10-20 mph, with higher gusts ( especially along mid-upper elevation mountain ridges-plateaus ). Areas of fog, with dense fog ( low cloud bases ) developing above 3000 feet. Temperatures by morning dropping into the upper 30s to upper 40s ( coldest at highest elevations ).
Wednesday Afternoon
Blustery & cold. Low cloud bases. Chance of drizzle at lower elevations and mix or flurries at highest elevations. Winds NW at 5-15 mph, with higher gusts. Temperatures holding nearly steady or falling through the 40s in lower-middle elevations, and through the 30s in upper elevations, amid locations along and north-northwest of the High Knob Massif & Tennessee Valley Divide ( some breaks possible within the stratocumulus overcast lee of mountains into river valleys of the Clinch, Powell, and Holston ). Wind chills in the 30s to low 40s in mid-elevations, below 3000 feet, and in the 20s to low 30s above 3000 feet.
Wednesday Night Into Thursday Morning
Cloudy & chilly. NW winds 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges & plateaus. Low cloud bases with light riming at highest elevations. Temperatures dropping into the upper 20s to the upper 30s ( coldest at highest elevations ). Wind chills in the 10s & 20s at highest elevations. Some cloud breaks possible leeward of mountains.
Thursday Afternoon
Sunny. Seasonally cool. Winds becoming WNW-W at mostly less than 10 mph outside of gustier high ridges. Temperatures varying from upper 40s to lower 50s in upper elevations to the mid 50s to around 60 degrees.
Thursday Night Into Friday Morning
Clear. Large vertical temperature spread between colder valleys and gusty mountain ridges. Winds SW to WNW at 10-20 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures varying from low-mid 20s amid mountain valleys ( colder in any high valleys that can keep calm winds ) to the mid-upper 30s. Wind chill factors in the 20s along gusty mountain ridges.
Weather Discussion ( Colder Air )
A blustery, cold day for early November is expected to be felt Wednesday behind a cold front. Low clouds and wind chills will be factors along the upslope side of mountains, especially along and north-northwest of the High Knob Massif and Tennessee Valley Divide.
Looking West Into Coalfields from High Knob Massif ( Forest Fire in Harlan County )
Widespread smoke which overspread the region from many forest fires burning across the southern Appalachians, from Kentucky and Tennessee into Georgia and western North Carolina, will be pushed back toward the south and southeast ( smoke from fires northwest of the area could continue to be smelt ) Thursday.
A changing flow pattern will mean more cold shots through coming weeks toward Thanksgiving, with eventually the chance for more significant precipitation.
NAM 12 KM Model Mean Sea Level Pressure & Wind Streamlines
A second cold front will bring a reinforcing shot of cold air into the mountain region by this weekend, with all locales having the potential for freezing & sub-freezing air ( even the mid-elevation thermal belt slopes & ridges ).
ALERT For Widespread Frost Into Saturday & Sunday Mornings, With A Hard Freeze In Mountain Valleys
***A NO BURN BAN Is Now In Effect
Overnight Into Saturday Morning
Clear & cold. Widespread frost developing. Light winds on mid to upper elevation mountain ridges. Hard freeze in the colder mountain valleys. Localized fog possible over major lakes & rivers. Temperatures varying from low-mid 20s in colder valleys to the low-mid 30s ( mildest mid-elevation thermal belt slopes-ridges and near major lakes-rivers ).
Saturday Afternoon
Mostly sunny ( deep blue skies ). Light northerly winds. Temperatures varying from upper 40s to lower 50s in upper elevations to the lower-middle 60s ( warmer south into the Great Valley ).
Saturday Night Into Sunday Morning
Mostly clear. Frosty cold in valleys. Hard freeze in the valleys. Light winds. Temperatures varying from 17-23 degrees in colder valleys of upper elevations to the low-middle 30s ( warmest mid-elevation thermal belts ).
Sunday Afternoon
Partly-mostly sunny ( some high clouds ). Light NE-ENE winds. Temperatures varying from low-mid 50s in upper elevations to the 60s across lower-middle elevations.
Sunday Night Into Monday Morning
Mostly clear. Large vertical temperature difference between frosty valleys & milder ridges. SE-S winds 5-15 mph, with higher gusts, on mid-upper elevation ridges. Temperatures varying from 20s to low 30s in mountain valleys to the mid-upper 40s on exposed ridges.
Monday Afternoon
Mostly sunny. Areas of smoke-haze. Winds SSE-SE at 5-10 mph with some higher gusts. Temperatures varying from 50s to around 60 in upper elevations to the mid-upper 60s to around 70 degrees.
Rain showers and colder air, with increasing RH on developing and gusty NW-NNW upslope flow is expected for Wednesday ( the drop of cloud bases will impact locations above 3000 feet ). Stay tuned for updates on this fire conditions impact event.
Weather Discussion ( Dry Air )
Widespread frost was observed on the ground and roof-tops from Clintwood to Norton on Saturday morning ( Nov 5 ) as low temperatures dipped into the 20s. It was as my grand-daddy used to say, “like a snow.”
Morning mins dropped into the 20s in mountain valleys, with 29 degrees officially being recorded in Clintwood. Higher mountain valleys fell into the low-mid 20s.
High Knob MesoNET – November 5, 2016
Around 10 hours, or locally more, were recorded with temps at or below freezing in high valleys. By contrast, a freeze in thermal belt locations ( exposed slopes-ridges ) was escaped with local readings as “mild” as the upper 30s.
Late PM Sun & Smoke From High Knob Meadow – November 5, 2016
Saturday morning featured very smoky conditions around Pound as NNE-NE flow was just enough to carry smoke into town from a fire burning on Pine Mountain. Meanwhile, it was clear & mainly smoke-free in Clintwood, Wise-Norton.
Lonesome Pine Airport In Wise
Only a slight wind shift from NNE-NE to NW-N allowed smoke from Pine Mountain to literally surge into the Norton-Wise & High Knob Massif area during Saturday afternoon. At least temporarily, with a subsequent wind shift back to NNE-NE again clearing much of the area.
*As winds shift more NE-ENE and eventually SE-SSE even the Pound area will clear as smoke will be pushed back toward Kentucky by later Sunday into Sunday Night.
Note that due to lower dewpoint air at higher elevations the fire conditions do not ease as much along ridges as they do in hollows and lower coves-valleys where nocturnal conditions feature rises in relative humidity as dewpoints-temperatures converge. This setting changes during the day as lower elevation RH drops.
Heavy frost is again, as expected, forming in valleys during this overnight-predawn of Sunday with another “snow” like covering being widespread into morning. Thermal belt sites will yet again miss another freeze.
*Thermal belt sites, as well as any other places that have not yet had a freeze, can now count the days before a freeze is observed as a major pattern change begins to occur across the Northern Hemisphere heading into mid-November.
Previous Discussion
Following enough rain to only dampen the forest, with totals varying from 0.03″ in Clintwood to a general 0.10″- 0.20″ within the High Knob Massif area, dry air is again reinforcing its grip on the mountain landscape.
Very dry air within the 900-800 MB layer will set the stage for cold temperatures both Saturday & Sunday mornings, especially within higher mountain valleys where I expect the first 10s to lower 20s of the season to be recorded. Mid-upper 20s being the coldest so far reported this autumn in the higher valleys.
October 2016 – The 850 MB Temperature Anomalies
The month of October 2016 ended 3.8 degrees above the 1981-2010 averages in both Clintwood and Wise, with MEAN temperatures of 56.8 degrees in Clintwood and 58.8 degrees on the campus of University Of Virginia’s College At Wise.
*There have been 4 October’s in Wise above 60.0 degrees with the warmest on record featuring a 61.5 degree MEAN temperature during October 1984 ( the great Arctic Outbreak in January 1985 followed to generate some of the coldest temps of all-time ).
October 1950 – The 850 MB Temperature Anomalies
Certainly one of the top analogs to this coast-to-coast warmth of October 2016 occurred in October 1950.
Closely compare October 1950 ( above ) with October 2016 and it is a rather amazing match. In the analog world it is about as close as one can get ( an analog typically referring to a previous set of weather conditions similar to what is being currently observed ).
A bad winter followed during 1950-51, with the GREAT Thanksgiving Snowstorm in November 1950 being one of the most amazing ( epic ) Appalachian storms of all-time.
The November 15, 1950 to February 15, 1951 period:
November 15, 1950 to February 15, 1951 – The 850 MB Temp Anomalies
Having a warm October and first half of November is not new; although, one would never know that if only listening to TWC ( The Warming Channel ). It is great to highlight the current state, but one must ( as Paul Harvey famously said ) also complete ( tell the rest of ) the story!
Rutgers University Snow Cover Extent
While the USA did have a mild October 2016, the expanse of total snow cover across the Northern Hemisphere came in at the third highest on record out of 49 years ( not that far behind the record set in October 1976 ). This was driven by rapid and extensive snow cover development across a good portion of Asia, centered upon Siberia, with an anomalous and weak Polar Vortex that has been undergoing what is a unprecedented ( for this time of year ) split.
European Model 10 MB Analysis For November 1, 2016
The split in the Polar Vortex in the stratosphere has occurred from the top ( above ) to the bottom ( below ).
European Model 150 MB Analysis For November 1, 2016
Arctic sea ice extent, by contrast to snow cover, is at a record low level for early November ( below ).
Arctic Sea Ice Extent At Record Low Level For Early November 2016
The last time I checked 1 + 1 = 2, so it is no surprise to me that snow cover expanse has been rapid and extensive around the Arctic Basin since open water = more moisture for evaporation and input into the atmosphere for snow.
The coldest air has developed on the opposite side of the North Pole, and has spread across much of Asia into portions of Europe ( below ).
October 27-November 2 Temperature Anomalies For Northern Hemisphere
Remember that while the Arctic Basin is warm relative to long-term averages, it is still plenty cold enough for snow production.
So while warmth has ruled the USA so far this autumn, many indications continue to suggest that a major pattern change will come to this side of the pole as well. Dryness will at least persist until this pattern change occurs into mid-late November ( with current odds favoring a wintry Thanksgiving to Christmas period ).
