An increasing chance for widespread showers and thunderstorms is being watched for mid-late week into this weekend as moisture from Harvey begins to finally lift north and east.
Overnight Into Monday Morning
High cloudiness. Areas of valley fog. Winds SSE-S at 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges. Temperatures varying from low-mid 50s in cooler mountain valleys and highest ridges to the lower 60s.
Remainder of Monday Afternoon
Cloudy ( mid-high clouds ). Small chance of showers, mainly west of the mountains in SE Kentucky. Light ESE-SSE winds generally less than 10 mph. Temps varying from the lower 60s within upper elevations to the lower 70s.
Monday Night Into Tuesday Morning
Mostly cloudy. Small chance of showers, especially to the southeast toward Mount Rogers-Whitetop. Areas of river valley fog. Winds E-SE at 5 to 15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures varying from the upper 40s to low 50s at upper elevations in the High Knob Massif to the mid-upper 50s.
Tuesday Afternoon
Partly to mostly cloudy. Chance of hit-miss showers and thunderstorms. Light winds. Temps varying from low-mid 60s in upper elevations to the low-mid 70s ( warmer south into the Great Valley ).
Tuesday Night Into Wednesday Morning
Partly to mostly cloudy. Areas of valley fog. Light winds. Temperatures in the 50s to around 60 degrees, except the upper 40s to low 50s within colder high valleys at upper elevations in the High Knob Massif.
Wednesday Afternoon
Partly to mostly cloudy. More humid. A chance for showers and thunderstorms by mid-late afternoon into the evening. Winds generally light and variable. Temperatures varying from mid-upper 60s at upper elevations to the mid-upper 70s to around 80 degrees.
Weather Discussion ( In The Middle )
Monday Evening Update
A solid mid-high altitude overcast has dominated Monday with abundant clouds streaming northeast from tropical storm Harvey. This held temperatures in the 60s and 70s, varying from lower 60s in the High Knob Massif to the low 70s in Clintwood ( 71.7 degree official maximum ).
High Knob Massif Webcam – University Of Virginia’s College At Wise
This update continues to highlight low rain chances over the mountains tonight, with a lesser chance for showers even toward the Blue Ridge as potential Irma along the Atlantic Coast struggles to develop within wind shear generated by Harvey and a polar jet stream.
Based upon late Monday evening readings, overnight temperatures in the high country of the High Knob Massif have been dropped a little from my previous forecast to account for lowering dewpoints and some possible over-night cloud breaks ( and decreasing predawn winds ).
Humidity + some instability will then offer a chance for localized shower-thunderstorm development Tuesday afternoon across the Cumberland Mountains.
NAM 12 KM Model Total Rainfall Forecast Next 84 Hours
Moisture related to the remnants of Harvey may begin to impact the mountain region by later Wednesday into the Thursday-Friday-Saturday period, with rainfall amounts and details yet to be determined.
Moisture from Harvey is looking increasingly like it will have some impact upon the area by late week-this weekend, per the latest ensemble means.
GFS Model Total Rainfall Forecast Next 132 Hours
While it has been a wet August in the mountains, with 7.00″ to 9.00″ widespread within the High Knob Massif – City of Norton and Big Stone Gap Water Plant area – just imagine that 3 to 4 times this much has fallen in the past few days over the area centered on Houston, Texas.
Month-To-Date Rainfall Estimated-Observed – Ending 8 AM August 28, 2017Estimated Rainfall Past 7 Days – Houston Tx Area – Ending 8 AM August 28, 2017
Previous Discussion
A few local downpours of rain, with lightning & thunder, developed Sunday to close out a seasonally cool weekend in the Cumberland Mountains. This as the mountain region is safely in the middle between the terrible impact of Harvey along the Gulf Coast of Texas and a developing tropical system near the Atlantic Coast.
Low temperatures of 40 to 45 degrees were reported within colder mountain valleys of upper elevations, with 50s being widespread elsewhere in the mountain area, during recent days.
High Knob Massif Webcam – University Of Virginia’s College At Wise
The heaviest rain developed along the U.S. 23 corridor between the City of Norton and Big Stone Gap.
NASA Visible Satellite Image At 6:00 PM on Sunday – August 27, 2017
Doppler radar estimated locally more than 1.00″ of rain near and just northeast of Big Stone Gap ( most of which fell within 1 hour ).
Doppler 1-Hour Estimated Rainfall Ending At 6:14 PM on August 27, 2017
With so much air rising over the remnants of Harvey and along the Tidewater of the southeastern USA it is likely any local rainfall will remain limited into mid-week ( due to synoptic-scale subsidence ). Meanwhile, there will be an abundance of high clouds over the area which are being sheared off the top of Harvey’s upper-level outflow.
USA Infrared Satellite Image At 3:15 AM on August 28, 2017
Some adjustments in cloud cover, temperatures, and the chance for showers may be needed depending upon the track of Harvey’s remnants during mid-late week.
European Model Mean Sea Level Pressure Forecast – 8:00 PM Friday ( Sept 1 )
The best chance for rain looks to be late this week into the weekend, when remnants of Harvey may finally get picked up by the jet stream. Stay tuned for updates.
A much cooler, autumnal air mass will be felt in coming days with chilly nights in mountain valleys ( and by day at high elevations ). While most places will drop into the range of upper 40s to middle 50s, colder mountain valleys at upper elevations will drop into the 40-45 degree range from the High Knob Massif to Burkes Garden. Cool nights are expected to continue into this weekend.
Overnight Into Wednesday Morning
Showers & thunderstorms into the early-mid overnight, local downpours likely, before tapering to showers. Winds SW 5 to 15 mph, with higher gusts, shifting northerly and decreasing into morning. Areas of dense fog, especially at highest elevations ( orographic clouds ). Temps widespread in the 60s ( dropping to around 60 degrees high elevations ).
Wednesday Morning Through The Afternoon
Any showers ending by mid-morning to mid-day, then becoming partly cloudy. Cooler. NNW-N winds 5-10 mph. Temps varying from low-mid 60s at highest elevations to the low-middle 70s ( warmer south into the Great Valley ).
Wednesday Night Into Thursday Morning
Becoming clear and chilly. Areas of dense valley fog. Winds NW-N at 5-10 mph on mid-upper elevation mountain ridges. Temperatures widespread in the 50s, except mid-upper 40s to lower 50s in upper elevations.
Thursday Afternoon
Partly cloudy. Beautiful blue skies. NW-N winds 5-10 mph, with some higher gusts along higher ridges. Temperatures varying from upper 50s to lower 60s at highest elevations to the upper 60s to lower 70s ( warmer into the Great Valley ).
Thursday Night Into Friday Morning
Clear & chilly. Areas of dense valley fog. Light N-NE winds along mid-upper elevation mountain ridges. Large vertical temperature spread between colder valleys-exposed ridges. Temperatures in the upper 40s to middle 50s, except 39 to 44 degrees in colder valleys above 2700-3000 feet.
Friday Afternoon
Partly to mostly sunny. Seasonably cool. N-NE winds 5 to 10 mph. Temperatures varying from low-mid 60s in upper elevations to the lower-middle 70s ( warmer south into the Great Valley ).
Friday Night Into Saturday Morning
Mostly clear & chilly. Areas of dense valley fog. Light NE to ENE winds along mid-upper elevation ridges. Large vertical temperature spread between colder valleys-exposed ridges. Temperatures in the upper 40s to middle 50s, except 40 to 45 degrees in colder valleys above 2700-3000 feet.
The inland track of remnant moisture from tropical activity in the Gulf of Mexico is being monitored for later next week. Stay tuned for updates.
A strong early autumn-like cold front is expected to bring a refreshing air mass change to the mountain region through coming days. While this will be notable at high elevations even during the day, it will be especially noticed during the night-time periods in mountain valleys.
Nocturnal dense fog formation will be likely in lower elevation valleys, especially along streams & rivers, with released latent heat of condensation helping keep temps milder ( upper 40s to lower 50s ) than locations with valley floors above 2700 to 3000 feet where lower dewpoints will enhance cold air drainage.
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 1-5
A very strong cool signal is indicated for the next 5 days. While below average temperatures are likely to continue into the 6-10 day period, there is increasing uncertainty, due mainly to tropical activity over the Gulf of Mexico, regarding mid-late next week ( Aug 30-Sept 2 ).
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 6-10
The strength and position of a trough over the eastern USA will play an important role in the eventual inland move-ment of tropical moisture over the Gulf of Mexico.
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 6-10
Weather Conditions Monday Will Be Influenced By A Solar Eclipse Between 1:00 PM and 4:00 PM, With A Temperature Drop Of 5 to 15 Degrees ( F ) Expected.
The Storm Prediction Center Has Issued A Marginal To Slight Risk Of Severe Thunderstorm Development For Tuesday Into Wednesday For Locations Along And West Of The Cumberland Mountains.
A Heavy Rainfall Potential Will Also Exist From Late Tuesday Into Wednesday Along And In Advance Of A Strong Cold Front.
Overnight Into Monday Morning
Partly cloudy. Areas of dense valley fog. Light SSE-SSW winds 5-10 mph, with higher gusts on mid-upper elevation mountain ridges. Calm valley winds. Temps varying from upper 50s to lower 60s in cooler valleys to the upper 60s to lower 70s on exposed mountain ridges.
Monday Afternoon & Solar Eclipse
Partly to mostly cloudy. Increasing darkness from 1:00 PM to 2:35 PM, then increasing daylight to 4:00 PM. Chance of a localized hit-miss shower or thunderstorm. Light SSE-SSW winds. Temps varying from the lower 70s to the lower 80s into early afternoon, then dropping 5-15 degrees depending upon the location and elevation before late afternoon rises occur prior to sunset.
Monday Night Into Tuesday Morning
Partly to mostly clear. Areas of valley fog. SSW-SW winds 5 to 15 mph, with higher gusts, along middle-upper elevation mountain ridges and plateaus. Temperatures mostly in the 60s, with some 50s possible in coolest mountain valleys.
Tuesday Afternoon
Partly-mostly cloudy. Chance of showers & thunderstorms. Downpours possible. SSW-SW winds 5-15 mph, with higher gusts. Temperatures varying from the low-mid 70s to the lower-middle 80s ( coolest in upper elevations ).
Tuesday Night Into Wednesday Morning
Showers & downpours in thunderstorms becoming likely. Heavy rainfall totals possible. SW-WSW winds 5-15 mph with higher gusts. Areas of fog, especially at the highest elevations. Temperatures widespread in the 60s.
Weather Discussion ( Solar Eclipse )
*Reference this section for a recap of the Eclipse:
Weather conditions at the beginning of this forecast period will be influenced by a rare solar eclipse, reaching around 96% totality in Norton-Wise ( 95% in Clintwood ) by 2:35 PM on Monday ( August 21, 2017 ).
Solar Eclipse Timing City of Norton-Wise
Begins: 1:07 PM
Peak: 2.35 PM ( 96% Totality )
Ends: 3:58 PM
*Since the sun will never be completely blocked by the moon at this latitude, DO NOT LOOK AT THE SUN WITHOUT PROTECTIVE, OFFICIAL ISO-RATED GLASSES.
A significant amount of cloud development will be possible by early afternoon over the Cumberland Mountains, such that some locations will likely have viewing problems. A small chance for local hit-miss showers-thunderstorms is also in my forecast.
Expect temperatures to drop 5 to 15 degrees between 1:00 PM and 2:45 PM, with precise drops dependent upon cloud coverage and elevation. Any places with thick clouds and showers could experience max drops, with high valleys and upper elevations within the High Knob Massif being favored for some of the largest temperature drops.
Storm Prediction Center Severe Thunderstorm Potential To 8:00 AM Wednesday
The focus turns toward another heavy rainfall potential setting by later Tuesday into Wednesday along and ahead of a strong cold front. The Storm Prediction Center has also issued a marginal-slight risk for severe thunderstorms for a large region along and west of the Appalachians.
Rainfall Totals ( August 1-18 )
City of Norton: 7.39″
Big Cherry Lake Dam: 7.62″
Eagle Knob of High Knob Massif: 8.67″
Due to wet antecedent conditions, strong rises on streams and other high water problems will be possible if heavy rainfall develops late Tuesday into Wednesday.
An ALERT For Local Downpours Of Heavy Rainfall Continues Through Friday Afternoon
A high water content air mass will continue over the mountain area into Friday afternoon. Showers & downpours with heavy to locally excessive rainfall will remain possible before much drier air overspreads the Cumberland Mountains by Friday night into Saturday morning. A beautiful weekend is expected.
Overnight Into Friday Morning
Hazy & humid. Areas of dense fog ( widespread at highest elevations within orographic clouds ). Chance of showers & thunderstorms, especially toward morning. Downpours possible. SW-W winds 5-15 mph, with higher gusts, along middle-upper elevation mountain ridges. Temperatures widespread in the 60s to lower 70s.
Friday Morning Into Friday Afternoon
Humid. Showers & thunderstorms likely. Local downpours. Low clouds with dense fog at highest elevations. Becoming partly cloudy and less humid by late afternoon into early evening. Winds shifting W-WNW at 5-10 mph, with higher gusts. Temperatures varying from upper 60s to lower 70s at highest elevations to the middle 70s to around 80 degrees. Warmer south into the Great Valley and Tri-Cities.
Friday Night Into Saturday Morning
Clearing and less humid ( especially in higher elevations ). Areas of dense valley fog. WNW-NW winds 5-10 mph and diminishing along all but highest ridges. Temperatures varying from lower 50s to the lower 60s ( coolest in high mountain valleys above 3000 feet ).
Saturday Afternoon
Partly sunny. Light SSW-WSW winds generally less than 10 mph. Temperatures varying from upper 60s to lower 70s at highest elevations to the upper 70s to lower 80s ( warmer south into the Great Valley and Tri-Cities ).
Saturday Night Into Sunday Morning
Mostly clear. Areas of dense valley fog. Light winds. Large vertical temperature spread developing between the cooler valleys and milder ridges. Temperatures varying from the upper 40s to lower 50s in coolest valleys to mid-upper 60s.
A more significant air mass change is being monitored for the final days of August, starting later next week, with potential for much less humid air and chilly nights. Stay tuned for updates.
Weather Discussion ( Jungle-like )
The mountain landscape during August 2017 has turned into a tropical, jungle-like state with very wet conditions featuring a daily array of downpours.
Month To Date National Weather Service and Estimated Rainfall Totals
*Automated Rain Gauge Totals ( August 1-17, 2017 )
Big Stony Creek: 8.27″
Dungannon: 7.98″
*Eagle Knob: 7.90″
*Robinson Knob: 7.21″
*Little Mountain: 7.10″
*Big Cherry Lake Dam: 7.04″
*Actual totals are greater, especially for rain gauge sites above 3000 feet in the High Knob Massif.
Month To Date National Weather Service and Estimated Rainfall Totals
Although coverage of heaviest rainfall amounts is greater than the above graphics indicate across southern Wise and northern Scott County, Va., they illustrate the general trend observed so far during August 2017.
NAM 12 KM Model Precipitable Water Forecast At 11:00 AM Friday – August 18
The current ( 11:45 PM Thursday ) presence of orographic clouds capping highest elevations within the High Knob Massif and Black Mountain, in advance of the approaching moisture plume ahead of a cold front, indicates that the potential for significant rainfall amounts must continue to be respected until drier air actually arrives later Friday afternoon-evening
Early morning to early afternoon is currently the period most favored for heavier rainfall with orographic enhancement.
Big Stony Creek of High Knob Massif – August 7 to August 18, 2017
Although dropping, stream levels remain high and swift on steep creeks draining the high country of the High Knob Massif. Please continue to use caution around these gushing whitewater creeks.
While humid, very moist air will continue to be felt into early Friday afternoon, a notable decrease in atmospheric moisture will occur by Friday evening into Saturday.
NAM 12 KM Model Precipitable Water Forecast At 8:00 PM Friday – August 18
The potential for a more significant air mass change, with an early autumn flavor, is being monitored for the final week of August ( the 5-10 day range at this point in time ).
European 51-Member Ensemble Mean 850 MB Temp Forecast: Days 6-10
ALERT For Local Downpours Of Heavy Rainfall Into At Least Friday – Caution Continues To Be Advised Along Creeks Draining The High Knob Massif
A high water content air mass will continue over the mountain area into at least Friday. Showers and downpours with heavy to locally excessive rainfall will remain possible.
Due to heavy rainfall Monday into early Tuesday, steep creeks draining the High Knob Massif continue to run very strong with ROARING water. Caution is advised around this swift water.
Overnight Into Monday Morning
Mostly cloudy. Humid & hazy. Areas of valley fog. Chance of a sprinkle or rain shower. Winds SSE to SSW winds 5-10 mph, with some higher gusts, along mid-upper elevation mountain ridges. Temperatures widespread in the 60s.
Monday Morning Through Monday Afternoon
Mostly cloudy. Humid. Chance of hit-miss showers and thunderstorms. Downpours possible. Light & variable winds outside any storms. Temperatures varying from upper 60s to low 70s in upper elevations to the middle to upper 70s ( warmer south into the Great Valley ). Areas of dense fog possible at highest elevations.
Monday Night Into Tuesday
Mostly cloudy. Humid & hazy. Areas of dense fog. Chance of a shower or thunderstorm. Winds SSW-WSW 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures in the 60s to near 70 degrees.
Tuesday Morning Through Tuesday Afternoon
A chance of showers & thunderstorms. Downpours possible. Winds SW-W at 5-10 mph along mid-upper elevation ridges. Temperatures varying from 60s in upper elevations to the middle-upper 70s ( warmer south into the Great Valley ).
Tuesday Night Into Wednesday Morning
A chance of showers & thunderstorms. Downpours possible. Winds SSW-WSW at mainly less than 10 mph along ridges. Temperatures varying from upper 50s to upper 60s. Areas of dense fog.
Wednesday Morning Through Wednesday Afternoon
A chance of showers & thunderstorms. Downpours possible. Light winds. Temperatures varying from upper 60s to low 70s in upper elevations to the upper 70s to lower 80s.
Wednesday Night Into Thursday Morning
A chance of showers & thunderstorms. Downpours possible. Winds SSW-WSW 5-10 mph, with higher gusts, along mid to upper elevation mountain ridges. Humid & hazy with areas of fog. Temperatures widespread in the 60s to lower 70s.
A stronger cold front and upper air trough is being monitored for later this week into race weekend at Bristol. The strength & south-ward progression of this feature will help determine conditions. Stay tuned for updates.
Weather Discussion ( Muggy Air )
Updated Discussion
A general 2.00″ to 3.00″ of rain fell across the High Knob Massif area into the day Tuesday ( August 15 ), with strong rises on creeks and local high water.
Big Stony Creek of High Knob Massif
Big Stony Creek crested 0.2 feet above flood stage in northern Scott County on Tuesday as run-off roared out of the high country. Both the Upper Norton Reservoir and the Big Cherry Lake are now overflowing their spillways.
A general 6.00″ to 8.00″ of rainfall has now been observed across southern Wise County and northern Scott County during the first half of August.
Saturated ground and the continuation of a high water content air mass increases the odds that downpours will cause additional, perhaps more significant, water problems in at least localized locations into Friday. I have posted an alert for everyone living and traveling across this water logged mountain terrain.
Stay tuned to NOAA weather radio and your favorite media sources for possibles advisories or warnings that may be needed during the next few days.
Previous Discussion
A muggy mass of air will continue to grip the mountain landscape through most of this week, with occasional showers and downpours being possible at times.
Thick Vegetation In Backwaters of Big Cherry Lake – August 13, 2017
A little less humid air was felt Sunday ( August 13 ) with MAX temperatures varying from upper 60s to upper 70s ( 79 degrees Clintwood and upper 60s on coolest northern slopes within the High Knob Massif ) in the Cumberland Mountains.
Towering Cumulus Over Powell Valley of the High Knob Massif
An abundance of clouds and low-level moisture will help to hold temperatures down, but muggy air will make it feel uncomfortable at most elevations.
NAM 12 KM Model Total Rainfall Forecast To 8 AM Thursday – August 17, 2017
Locally heavy rainfall will be possible, but models will also continue to struggle to pinpoint where that occurs well in advance of developing activity ( therefore, nowcasts or very short-term forecasts, based on Doppler radar, will remain most accurate during this type of pattern ).
GFS Model Total Rainfall Forecast To 8 PM Friday – August 18, 2017
A stronger cold front and upper air trough will be approaching the mountain region by later this week into the upcoming weekend. The speed, strength and south-ward progress of this feature will be key to conditions experienced during race week-weekend ( and perhaps during the eclipse on August 21 ).
***ALERT For Heavy Rainfall Development Overnight Into Monday With Potential For Water Problems
A strong SW low-level jet will enhance orographic forcing overnight into Monday in advance of an approaching storm system. Heavy to locally excessive rainfall will be possible, especially within the most favored lifting zones centered upon the High Knob Massif & Black Mountains-Tennessee Valley Divide. Those living and driving along streams and within typically flood prone & poor drainage areas should remain alert for the potential of rapid water level rises.
Former Alerts
The Storm Prediction Center Has Issued A Marginal Risk Of Severe Thunderstorm Development During Friday Afternoon-Evening
Friday Afternoon
Showers & downpours in thunderstorms developing. Some storms could be strong to locally severe. SSW-WSW Winds 10-20 mph, with higher gusts, along mid-upper elevation mountain ridges-plateaus. Temperatures varying from 60s in upper elevations to the mid-upper 70s ( warmer south into the Great Valley ).
Friday Night Into Saturday Morning
A chance of hit-miss evening showers-thunderstorms then becoming partly to mostly clear overnight. Areas of fog. Winds shifting NW-N at 5-15 mph. Turning cooler. Temps varying from the mid-upper 40s to the upper 50s ( coolest within upper elevations ).
Saturday Afternoon
Partly to mostly sunny. Blue skies. Pleasant. Light NW-N winds. Temperatures varying from 60s in upper elevations to the low-middle 70s.
Saturday Night Into Sunday Morning
Clear evening skies, then increasing high clouds overnight into morning. Light winds, then becoming SE-S along high mountain ridges and increasing toward morning. Large vertical temperature spread between colder valleys and milder ridges. Temperatures varying from 40s in colder mountain valleys to the upper 50s to lower 60s ridges.
Sunday Afternoon
Partly-mostly cloudy. More humid. Chance of a localized shower or thunderstorm. Light winds, except breezy-gusty on high mountain ridges from the SSW-SW by late. Temps varying from upper 60s to lower 70s in upper elevations to the upper 70s to lower 80s.
Sunday Night Into Monday Morning
Cloudy. Becoming windy across the higher elevations. Showers & downpours in thunderstorms developing. Heavy rainfall totals possible. SSE to SSW winds increasing to 10-20 mph, with higher gusts, along mountain ridges-plateaus below 2700 feet. Winds SSW-WSW 15-25 mph, with higher gusts, on mountain ridges above 2700 feet. Temperatures varying from the upper 50s to mid-upper 60s. Dense fog developing across upper elevations.
Monday Morning Into The Afternoon
Showers & downpours in thunderstorms. Heavy rainfall totals possible. SW winds 10-20 mph, with higher gusts, across mountain ridges-plateaus. Temperatures in the 60s to lower-mid 70s ( coolest at highest elevations ). Dense fog across upper elevations.
A wet and occasionally stormy pattern is expected this week with below average temperatures for August. More heavy rainfall may become possible by later in the week. Stay tuned for updates.
Weather Discussion ( Changeable )
A beautiful weekend featuring chilly night-time temps, with 43 to 49 degrees in cooler mountain valleys, will now give way to a return of deep moisture driven by a low-level jet of strong SW winds overnight into Monday ( Aug 7 ).
NAM 12 KM Model Total Rainfall Forecast Next 60-Hours ( Sunday AM Run )
Although models vary from run to run on precise amounts for any given location, the general trend is clear when also including the European Ensemble Group ( 51-Members ) that a heavy rainfall setting is emerging for the mountain area.
NAM 12 KM Model Total Rainfall Forecast Next 60-Hours ( Sunday PM Run )
Past climatology of many such events, featuring a SW low-level jet, favors heaviest rain amounts being focused upon the High Knob Massif-Landform & Tennessee Valley Divide corridor, and locations along and generally west of the Tennessee-North Carolina border.
Stay tuned to NOAA Weather Radio and your favorite media sources for possible watches and/or warnings that may be needed through Monday.
Previous Discussion
Another cold front with showers and downpours in thunderstorms during Friday will give way to another pleasant weekend in the mountains.
High Knob Massif Webcam – University Of Virginia College At Wise
A general wet pattern is looking to develop next week into mid-August, but exact amounts for any location remain in question and must be updated in coming days.
GFS Model 2 AM Run Friday – Forecast Rainfall Next 10 Days
While the numbers will vary for any given place, the mean of ensembles, such as the favored European Model group, is suggesting that a wet pattern will rule the landscape.
GFS Model 8 AM Run Friday – Forecast Rainfall Next 10 Days
The other main theme will be a continuation of below average temperatures across much of the continental USA, outside of the Pacific Northwest, for late summer.
European Ensemble MEAN 850 MB Temp Anomalies: Days 1-5
Near to above average temperatures are also expected across Florida, but nothing like the heat ( relative ) at higher latitudes across North America.
European Ensemble MEAN 850 MB Temp Anomalies: Days 6-10
It has been a relatively cool summer in the high country of the High Knob Massif, as illustrated by High Knob Lake.
High Knob Lake of High Knob Massif – August 1, 2017
High Knob Lake June-July 2017 Temperatures Average Daily MAX: 71.2 degrees Average Daily MIN: 55.6 degrees June-July MEAN: 63.4 degrees Highest Temperature: 80 degrees Lowest Temperature: 44 degrees
Even cooler temperatures, especially at night, have been recorded within the Big Cherry Lake Basin where average nightly low temperatures have been as chilly as 51 degrees for the combined June-July period ( the lowest summer MIN reaching 38 degrees on June 28 ).
The coolest day-time temperatures have occurred at highest elevations, with 68.4 degrees being recorded on Eagle Knob for the average June-July maximum ( highest summer temp reaching 77 degrees on July 22 ).
An Alert For Dense Fog Is In Effect For Elevations Above 2600 to 3000 Feet Within The Cumberland Mountains Through 10:00 AM Saturday
Cooling air on northerly upslope flow in the wake of widespread, heavy rains will allow cloud bases to remain low through morning hours of Saturday. Caution is advised for those traveling at higher elevations overnight into Saturday morning.
Previous Alerts
The Storm Prediction Center Has Issued A Marginal To Slight Risk For Severe Thunderstorm Development On Thursday Into Friday ( July 27-28 )
Locally Heavy To Excessive Rainfall Will Be Possible Thursday Into Friday Ahead Of A Strong Cold Front That Could Lead To Local High Water Problems
Overnight Into Thursday Morning
Increasing high clouds. Hazy & humid. Areas of valley fog. Winds SSW-WSW 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures varying from low-mid 60s to around 70 degrees.
Thursday Morning Through The Afternoon
Showers & downpours in thunderstorms developing in a hit-miss fashion. Some storms could be strong to locally severe. SW winds 5-10 mph, with higher gusts. Temps varying from upper 60s to lower 70s in upper elevations to the upper 70s to lower 80s ( warmer south toward the Tri-Cities ).
Thursday Night Into Friday Morning
A chance of showers & thunderstorms. Downpours possible. Winds S-SW 5-10 mph, with higher gusts. Hazy, humid with areas of fog. Warm with temperatures in the 60s to low 70s.
Friday Morning Through The Afternoon
Showers & downpours in thunderstorms becoming likely. Some storms could be strong to locally severe. Winds S-SW 5-15 mph, with higher gusts at elevations below 2700 feet. Winds SW to W 10-20 mph, with higher gusts, at elevations above 2700-3000 feet. Temperatures in the 60s to low 70s. Low cloud bases with dense fog at upper elevations.
Friday Night Into Saturday Morning
Rain showers. Turning cooler. Winds shifting NNW-NNE at 5 to 15 mph, with higher gusts. Temperatures dropping into the 50s to low-mid 60s ( coolest at highest elevations ). Low clouds with dense fog at higher elevations.
Saturday Morning Through The Afternoon
Morning showers ending with low cloud bases lifting into afternoon. Skies becoming partly to mostly cloudy. Winds NNW to NNE at 5 to 15 mph, with some higher gusts along mountain ridges. Temperatures varying from upper 50s to lower 60s at highest elevations to the upper 60s to lower 70s ( warmer south into the Great Valley ).
Low temperatures are expected to fall into the 40s to low-mid 50s into Sunday morning ( coolest within higher mountain valleys ).
The coldest mountain valleys at upper elevations, from the High Knob Massif to Burkes Garden, are expected to drop into the 40 to 45 degree range on both Sunday and Morning mornings, with an increasingly large vertical temperature spread expected by early Monday as exposed ridges fall only into the upper 50s to low 60s. If cooling conditions are perfect, coldest spots may dip just below 40 degrees as most recently observed on June 28.
Weather Discussion ( Cold Front )
A strong cold front for late summer is the main focus of this weather period, with a major air mass transition occurring during the weekend.
Looking At Mount Rogers – Mount Rogers NRA on July 20, 2017
Air temps will hold in the 50s on highest peaks from the High Knob Massif to Mount Rogers during the day Saturday ( illustrating the early autumn-like nature of this upcoming air mass change ).
NAM 12 KM Model Total Rainfall Forecast – Next 72 Hours
Some orographic forcing will develop as this cold front approaches, with potential to off-set the general trend of dryness observed during the past 30-60 days.
Although November-April is the prime orographic forcing season, with October & May often being months of transition, when large-scale storm systems develop pressure gradients that push upon the mountain terrain ( the mountains “push back” and generate torques on the atmosphere ), orographic forcing settings can and occasionally do develop during the convective season.
NWS Precipitation Anomalies And Estimated Coverage – Past 30 Days
Heavy to excessive rains to the north, with rising air from Ohio to Wisconsin, has aided summer dryness across much of Virginia, SE Kentucky, northeastern Tennessee and portions of North Carolina where air has been sinking by compensation ( couplets of rising-sinking air are common on both local and synoptic scales during the convective season, often dictating patterns of summer rain ).
This general pattern has been superimposed upon local dry-wet feedbacks, favoring large rainfall variations over short distances.
Measured Rainfall Since June 1
Clintwood 1 W: 5.94″ ( -2.83″ below 1981-2010 average )
Nora 4 SSE: 10.23″ ( Near To Above Average )
Summer 2017 rainfall has varied dramatically across Dickenson County, for example, with about twice as much falling upon Long Ridge of Sandy Ridge as in Clintwood since the beginning of June.
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 1-5
Although more summer certainly lies ahead, recent heat will be broken and a near to below average temperature pattern is currently predicted by the European ensemble MEAN during the next 5-10 days into early August.
European 51-Member Ensemble Mean 850 MB TEMP Anomalies: Days 6-10
Partly-mostly clear. Areas of valley fog. Light winds. Temperatures varying from mid-upper 50s to lower 60s within cooler valleys to the middle-upper 60s.
Tuesday Afternoon
Partly to mostly cloudy skies. A chance of hit-miss showers and thunderstorms. Light winds. Temps varying from the 70s in upper elevations to the mid-upper 80s.
Tuesday Night Into Wednesday Morning
Chance of a hit-miss evening shower or thunderstorm. Hazy and humid with areas of valley fog. Light SSW to W winds generally less than 10 mph on mid-upper elevation mountain ridges. Temps in the 60s to near 70 degrees.
Wednesday Afternoon
Partly-mostly cloudy skies. Hazy-humid. A chance of hit-miss showers and thunderstorms. WNW-NW winds 5-10 mph, with higher gusts ( especially on mountain ridges ). Temperatures varying from 70s in upper elevations to the mid-upper 80s.
Wednesday Night Into Thursday Morning
Warm & humid. A chance of hit-miss showers & thunder-storms. NW-NNW winds 5-15 mph, with higher gusts, on middle-upper elevation mountain ridges-plateaus. Temps in the 60s to lower 70s.
Thursday Afternoon
Partly-mostly cloudy skies. Hazy & humid. A chance of hit-miss showers & thunderstorms. Winds NW-NNW 5-10 mph. Temperatures varying from 70s in upper elevations to the mid-upper 80s ( warmer, as per each day, at low elevations south of the High Knob Massif and in the eastern Kentucky foothills and lower sections of the Russell Fork-Levisa Fork river valleys around Haysi and Grundy ).
Weather Discussion ( Dog Days )
The somewhat lower humidity of recent days is being replaced by a more humid air mass, with a dominant and deep NW-N flow regime aloft developing around a large heat dome centered over the central USA.
High-Elevation Meadow In High Knob Massif – Elevation 3900 feet – July 15, 2017
The afternoon MAX reached 70 to 74 degrees at highest elevations in the High Knob Massif on Saturday, July 15, as relatively pleasant weekend conditions were observed in the high country ( nocturnal low temps dropped to 50-55 degrees within high valleys ).
To the south, by contrast, weekend conditions remained hot in the Great Valley with upper 80s to lower 90s reported from Knoxville into the Tri-Cities.
Turk’s-cap Lilies ( Lilium superbum ) Bloom In High Knob High-Country – July 15, 2017
Rainfall has been hit or miss during the past week, with a notable dry trend since the start of Meteorological Summer ( on June 1 ) across much of the Cumberland Mountains, at least relative to what is average for this time of year.
National Weather Service Rainfall Analysis – Past 7 Days
Note heavy, locally excessive, rains to the north across Indiana and Ohio as thunderstorm clusters moved around the periphery of heat last week. Rain was locally heavy across Dickenson-Buchanan counties & adjoining locales in eastern Kentucky and southern West Virginia as a front passed during the July 13-14 period.
Although 1.25″ of rain fell in Clintwood during July 14, only 5.26″ have been measured since June 1 ( 2.14″ below the 1981-2010 avg. ), which is also about the same as observed at Big Cherry Lake Dam. A total of 7.68″ have been measured at Nora 4 SSE on Long Ridge of Sandy Ridge, in between these two sites, to illustrate the hit-miss nature of Summer 2017 convection.
USA Water Vapor Image At 1:15 AM on July 18, 2017
A upper low over central Virginia-North Carolina will be pushed eastward as the heat dome initially expands, with deep NW-N flow aloft that may carry debris cloudiness from thunderstorm clusters forming on the periphery of blazing heat over the Upper Midwest.
A hit-miss pattern of convective activity is expected to continue as heat builds through the remainder of this work week. Changes will be possible by this weekend into next week, especially, as troughing develops aloft and monsoon moisture continues to flow around the big heat dome.
European 51-Member Ensemble MEAN 500 MB Height Anomalies: Day 1-5
An increasing potential for showers-thunderstorms will occur over time with a retrogression of the heat dome core, especially by later this weekend into next week ( this is the current ensemble trend ). Stay tuned for updates.
European 51-Member Ensemble MEAN 500 MB Height Anomalies: Days 6-10
1 ). A Mesoscale Convective System will drop south to southeast toward the mountains Friday Night into the early hours of Saturday. While a weakening trend is expected, strong to locally severe thunderstorms will remain possible as this cluster of storms approaches the Cumberland Mountains.
HRRR Model Future Doppler Radar Forecast At 1:00 AM Saturday – July 8, 2017
The main storm threats are damaging winds, lightning and heavy rainfall. This system is expected to weaken across the higher mountain terrain overnight.
2 ). Rain cooled outflow from this system & approach of a surface cold front will trigger new development from the morning into afternoon hours of Saturday.
JKL Doppler At 9:27 PM Friday – July 7, 2017
An outflow boundary just north of Jackson, Ky., at 9:27 PM is starting to move out ahead of the MCS, indicating a trend toward weakening during coming hours. Any left-over boundaries + the surface front will bear watching for new development following onset of day-time heating Saturday.
3 ). Drier, less humid and more stable air is expected to overspread the mountains from northwest toward southeast by late Saturday afternoon into Sunday.
Lower dewpoints will make conditions feel much better from Saturday Night through Sunday Night, with notable cooling within mountain valleys ( MINS in the 50s will be widespread across the area, with coolest valleys dropping into the 40s to contrast with upper 50s to low-mid 60s on exposed mountain ridges Sunday & Monday mornings ).
4 ). A ring-of-fire pattern will become possible next week around the periphery of a building heat dome with rising day-time temperatures early next week.
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 4-8
A modeling trend ( ensemble mean ) is for a heat dome to set up near the Red River Valley & Texas-Oklahoma panhandles next week. This will generate a WNW-NW flow pattern and ring-of-fire convective regime ( i.e., clusters of showers and thunderstorms will develop along the edge of the hottest air and move around the periphery of the heat dome ).
European 51-Member Ensemble MEAN 500 MB Height Anomalies: Days 6-10
The eventual location of the heat dome core will need to be followed, along with the recent dry feedback tendency that has generated below average rainfall across portions of the mountain region during June-early July ( local wet feedback has also been observed as typical of patterns featuring hit-miss convective development & movement ).
The Storm Prediction Center Has Issued A Marginal Risk Of Severe Thunderstorm Development Saturday
Friday Morning Through Friday Afternoon
Predawn rain showers and rain developing ( especially along and southeast of the High Knob Massif & Tennessee Valley Divide. Dense fog at highest elevations. Then partly cloudy with a chance of showers and thunderstorms this afternoon. Local downpours. SSW-SW winds 5 to 15 mph, with higher gusts. Temperatures varying from 60s to low 70s in upper elevations to the upper 70s to lower 80s.
Friday Night Into Saturday Morning
Chance of hit-miss showers or thunderstorms. Partly to mostly cloudy. Areas of fog. SSW-WSW winds 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges and plateaus. Mild with temperature widespread in the 60s ( upper 50s to lower 60s in cooler locations ).
Saturday Afternoon
A chance of showers & downpours in thunderstorms. Some storms could be locally strong-severe. SW winds 5-15 mph, with higher gusts. Temperatures varying from upper 60s to lower 70s at highest elevations to the upper 70s to low 80s. Areas of dense fog ( orographic clouds ) at upper elevations.
Saturday Night Into Sunday Morning
A chance of showers & thunderstorms. Winds shifting to WNW-NW at 5-10 mph, with higher gusts. Areas of fog, especially at high elevations. Temperatures dropping into the upper 50s to middle 60s ( coolest highest elevations ).
Intervals of showers & downpours in thunderstorms are expected through most of next week in advance of a stronger cold front that could again introduce much cooler air by the second week of July. Many dry hours are expected between active weather. Stay tuned for later updates on this future weather pattern.
Weather Discussion ( Back To Summer )
A return of humid air means that a return of more typical summer conditions, with intervals of showers & thunder-storms, will be a common feature of the forecast through the Independence Holiday period and next week.
Big Cherry Wetland Valley of High Knob Massif – June 28, 2017
Coldest mountain valleys along the Appalachians fell into the 30s, prior to this return of summer, with widespread 40s in other valleys across the Mountain Empire.
Coldest Mountain Valley Reports ( Morning Of June 28, 2017 )
Canaan Valley West Virginia 37 degrees
Burkes Garden Virginia 37 degrees
*Big Cherry Wetland Valley 38 degrees
A June 1-29 mean low temperature of 47.6 degrees was recorded in colder portions of the Big Cherry Wetland Valley ( 49.9 degrees in Burkes Garden during this same period ).
Following a very WET April-May, the month of June will end with near to below average rainfall. Many local locations are currently in the 3.00″ to 5.00″ rainfall bracket ( as of AM on June 30 ).
June featured a host of nice, chilly nights amid high valleys with 16 out of the 29 days of June featuring a 24-hour MIN which dropped below 50 degrees in the Big Cherry Lake Wetland Valley of the High Knob Massif.
Storm Prediction Center Risk Regions From 8 AM Saturday To 8 AM Sunday
Strong to possibly severe thunderstorm development will be possible Saturday, with formation west of the mountains tending to move eastward. Be sure to stay tuned to NOAA Weather Radio and your favorite media sources for any possible watches or warnings that may be issued.
