Partly cloudy & hazy. Humid. Areas of dense valley fog. Light southerly winds along mid-upper elevation ridges. Temps in the 60s to around 70 degrees.
Sunday Afternoon
Partly sunny. Hazy & humid. Chance of hit-miss showers and downpours in thunderstorms. Winds becoming E-NE at 5-10 mph. Temperatures varying from middle to upper 70s in highest elevations to mid-upper 80s ( hotter southward into the Great Valley ).
Sunday Night Into Monday Morning
Chance of hit-miss evening showers-storms; otherwise, partly cloudy. Areas of dense fog. E-SE winds 5-10 mph along mid to upper elevation mountain ridges. Temps varying from upper 50s to the upper 60s.
Monday Afternoon
Partly cloudy. Chance of hit-miss showers-thunderstorms. Winds ENE to NE 5-10 mph, with some higher gusts. Temps varying from low-mid 70s in upper elevations to the lower-middle 80s ( hotter south into the Great Valley ).
Monday Night Into Tuesday
Evening thunderstorms diminishing. Partly cloudy & humid. Areas of dense fog. Light E-NE winds along mid-upper elevation ridges. Temperatures in the 60s to around 70 degrees.
Tuesday Afternoon
Partly cloudy. Chance of hit-miss showers-thunderstorms. Winds E to NE 3-10 mph. Temperatures varying from mid-upper 70s in upper elevations to mid-upper 80s ( hotter south into the Great Valley ).
Tuesday Night Into Wednesday Morning
Chance of hit-miss showers & downpours in thunderstorms. Humid. Areas of fog. Light & variable winds. Temps in the 60s to around 70 degrees.
Weather Discussion ( Final Days )
Late summer heat and humidity helped trigger some booming storms across the mountain area Monday, in hit or miss manner as forecast, with downpours and gusty winds.
Clouds Tower Above Cumberland In Late Summer Heat
Rainfall totals locally topped 0.50″ in just 15-20 minutes in places that got hit hardest with downpours ( e.g., Big Cherry Lake Basin and along Pine Mountain from Breaks Interstate Park southwest toward Pound Gap to note a couple areas ).
The same pattern holds during Tuesday-Wednesday before a cold front arrives Thursday, with cooler and much less humid air again taking control Friday into the Labor Day Holiday Weekend ( beyond that sinking air in wake of passing tropical systems may rebuild the heat ridge ).
Model Spaghetti Tracks On Pre-Hermine Development
Models have finally come into general agreement on the likely formation of former Invest 99L, now Tropical Depression 9, with a movement across northern Florida and back into the Atlantic being the one currently favored.
National Hurricane Center 5-Day Track Forecast For TD9
It is not impossible, of course, that TD8 could beat TD9 to the Hermine name as it briefly intensifies over the Gulf Stream approaching the North Carolina Outer Banks.
National Hurricane Center 5-Day Forecast Track For TD8
Sinking air in the wake of these, by late in the weekend-early next week, will help rebuild heights to the west and likely allow the TRI to add a few more 90s that could help them reach the record for the most 90-degree days ever officially observed in the Tri-Cities.
Shorter days and longer nights will eventually take its toll on summer heat, especially into mid-late September when most years feature significant autumn color changes amid upper elevations of the High Knob Massif ( above 2700-3000 feet ). I, for one, greatly look forward to this color season!
Previous Discussion
The final days of August means it is also the final days for Meteorological Summer 2016. Many will say good riddance given the nearly relentless humidity in the mountains and heat+humidity in the Great Appalachian Valley.
August 27 Temperature-RH at NWS Station In Clintwood
August 27 ( Saturday ) was one of the hottest days of the entire summer ( and the hottest day in August ) within the Cumberland Mountains, with the above temps being recorded in Clintwood between 6:40 AM and 6:40 PM.
The 89.4 degrees PM MAX combined with a muggy 66 degree dewpoint reading ( 48% relative humidity ) to generate a 93 degree Heat Index.
Doppler Radar Rainfall Estimate For August 27, 2016
A few showers and downpours in thunderstorms managed to develop, with some of the heaviest action just southwest of Cumberland Gap. More downpours fell along Guest River Gorge, close to ( if not over ) the rain gauge of Jerry Rose where he’d already measured more than 7.00″ in August.
Most places remained dry.
NAM 12 KM Model Total Rainfall Forecast Next 3-Days
The same pattern holds through the next several days, with a little more cloud coverage over the mountains and a little better coverage of hit or miss showers-storms. Note that emphasis continues to be on hit-miss activity that fights against sinking air aloft to develop amid heat-instability.
Meanwhile, the saga of Invest 99L continues!
Model Spaghetti Tracks For Invest 99L
While possible tracks ( above ) are spread about as wide as they can get, the spread in intensity forecasts ( below ) are perhaps even more impressive with variations from a CAT 4 to not being more than a depression ( at best ).
Model Spaghetti Intensity Forecast For Invest 99L
Even the typically dependable European Model has had large run-to-run variations, and large differences among it’s ensembles. Stay tuned!
Partly cloudy. Areas of dense valley fog. Winds S to SW at 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures in the upper 50s to mid-upper 60s.
Thursday Afternoon
A chance of hit-miss showers & thunderstorms. Partly cloudy. Hazy. Winds S-SW at 5-10 mph, with some higher gusts along highest ridges. Temperatures varying from the low-mid 70s in upper elevations to the lower-middle 80s.
Thursday Night Into Friday Morning
Partly to mostly clear. Areas of dense valley fog. SW winds becoming northerly into morning at 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges. Temps varying from lower 60s to around 70 degrees.
Friday Afternoon
Partly to mostly sunny. Hot. Light N to NE winds. Temps varying from middle-upper 70s in upper elevations to the middle to upper 80s ( hotter south into the Great Valley ).
Friday Night Into Saturday Morning
Mostly clear. Areas of dense valley fog. Light E-SE winds. Temperatures varying from 50s in the coolest mountain valleys ( mid-upper elevations ) to the mid-upper 60s.
Saturday Afternoon
Partly sunny. Hot & humid. Chance of a hit-miss shower or thunderstorm. Light SSE-SSW winds. Temps varying from mid 70s to around 80 degrees at highest elevations to upper 80s to around 90 degrees ( hotter into the Great Valley ).
Saturday Night Into Sunday Morning
Partly cloudy. Humid. Areas of dense valley fog. Light southerly winds along mid-upper elevation ridges. Temps in the 60s to around 70 degrees.
Weather Discussion ( More Summer )
A heat ridge centered near the Great Smokies is well known climatologically as a heat maker for the Mountain Empire, even in the final days of the Meteorological Season.
Sinking Air Beneath Late Summer Heat Ridge – Northern Dickenson County
Although some afternoon cumulus formed Thursday and Friday, especially along major lifting zones like the High Knob Massif, the atmosphere was clearly being dominated by subsidence aloft.
Mathematically deriving the Law Of Conservation Of Mass, from which various forms of the Continuity Equation is obtained, it is easy to develop a basic Subsidence Model for the atmosphere that clearly illustrates the relationship between rising & sinking air.
Essentially, low-level rising in one region of the atmosphere must be compensated for by large-scale sinking within another region. While we often focus on convection that forms in a ring around high pressure centers it is seldom noted how air spreading out aloft above the convection acts to support and reinforce, via compensative subsidence, the adjacent high pressure.
Model Spaghetti Forecast Track For Invest 99L
So even as Invest 99L struggles, and models struggle with what it will eventually do, there will be significant low-level convergence across the Gulf of Mexico into the Upper Midwest through coming days that will continue to support the large-scale subsidence of air that is dominating the Mountain Empire. The result being heat, humidity and little rain ( only localized storms in places where orographics and/or instability may briefly overcome sinking ).
Eventually, as is true of all things, this will change but for now this is the Bottom Line of the Big Picture.
Model Spaghetti Intensity Forecast For Invest 99L
*While rising-sinking ( outside of that orographically forced ) is not as coupled in mid-latitudes on the synoptic-scale as it is amid the tropics, the principle still applies and regions where synoptic high pressure is favored can be ( and often are ) aided by these processes ( since mass can be neither created nor destroyed, only rearranged in space & time and/or transformed in ways that still result in the total mass remaining unchanged ).
Previous Discussion
Following a short-stretch of simply gorgeous conditions that featured a few 40s in high mountain valleys, the heat of Summer 2016 is returning.
Pristine Water In Big Cherry Lake Basin – August 22, 2016
The lazy, hazy, crazy days of August also feature plenty of noise courtesy of Annual Cicadas ( below ) that tend to be plentiful at this time of year.
These are in a different genus from Periodical Cicadas that erupt in cycles of 13-17 years, forming one of the greatest natural events on planet Earth which is endemic to eastern North America.
National Weather Service stations in Wise and Clintwood have not recorded a day above the low 80s during the past seven days, since August 17 ( the MAX being recorded for the 24-hours ending during the AM of August 18 ).
NWS Station – UVA Wise – Observers Bob Vangundy & Layton Gardner
The morning of August 23 has been the coolest, with 52 degrees on the plateau at the University Of Virginia’s College At Wise and 40s in adjacent valleys from the City of Norton upward into the high country of the High Knob Massif. A brief preview of Autumn!
Dense fog prevented the MIN from dropping below 54 degrees in Clintwood and most valleys across the lower elevations ( below 2000 feet elevation ).
NWS Station In Clintwood – Observer Wayne Browning
August rainfall of exactly 3.56″ in both Wise and Clintwood might suggest that rains had fallen evenly during the past 3 weeks; however, that is not the case as exemplified by 5.59″ measured in the official rain gauge at the City of Norton Water Plant by Andrew Greear & Staff, and more than 7.00″ measured by Jerry Rose in the Crab Orchard community near Guest River Gorge of the High Knob Massif.
August rains have also varied significantly across the Big Cherry Lake Basin, with 4.38″ at Big Cherry Dam being in contrast to more than 6.00″ across the basin head near the High Knob peak.
NAM 12 KM Model Precipitable Water Forecast At 8 AM Saturday – August 27
Following a chance for hit-miss showers & thunderstorms on Thursday, drier air aloft with subsidence will lower the total precipitable water values in the atmosphere Friday into Saturday to aid late season summer heating.
From August 25 onward through the remainder of the year only 4 days have ever been able to break 90 degrees in Wise, such that the window for this type of heat is closing with shorter days, longer nights and lowering sun angles.
In order to break 90 degrees from this point forward, in the middle elevations of the Cumberland Mountains ( between 2000-3000 ft ), everything must fall into perfect alignment ( mainly…either dry ground + few to no clouds + sinking air and/or normal wetness + few to no clouds with strongly sinking air ).
So the key to perhaps hitting 90 again ( for the 2nd time ) in either Wise or Clintwood will be for the air to dry out aloft with subsidence to prevent cloud formation. It is difficult to do on the heels of an average to above average rainfall summer, but Friday-Saturday will attempt this feat.
Meanwhile, temperatures in the Great Valley of eastern Tennessee will blaze under conditions like this with downslope flow in lower levels combined with subsidence aloft over ground that remains drier than average in wake of a very dry June 1-August 15 period.
Spaghetti Model Tracks For Invest 99L
The main focus from this weekend into next week will be on Invest 99L and its potential for development into a tropical storm and hurricane. Will it impact the Appalachians in a direct manner, with heavy rainfall? That is impossible to tell at this point in time. Stay tuned for updates.
However, some impact is almost certain as even if the storm’s rain shield passes well to the east, a zone of strong subsidence will be to its west and help prolong the heat of Summer 2016 for places that get under its ring of sinking air ( via the Law of Conservation of Mass ).
Caution For Swift Water On Steep Creeks Draining The High Knob Massif Into Monday
Sunday Night Into Monday
Mostly clear. Cooler & refreshing. Areas of dense valley fog. Winds WNW-NNW 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures in the 50s to near 60 degrees ( 50-55 degrees in cooler locations ).
Monday Afternoon
Partly sunny. Beautiful skies & pleasant. Winds NW-N at generally less than 10 mph. Temperatures varying from 60s in upper elevations to the mid-upper 70s.
Monday Night Into Tuesday Morning
Clear & cool. Areas of dense valley fog. Light winds, except winds becoming E-SSE at 5-10 mph along the highest ridges. Temperatures varying from 40s in cooler mountain valleys of mid-upper elevations with limited fog to the mid-upper 50s on exposed middle-upper elevation ridges.
Tuesday Afternoon
Partly-mostly sunny. Warmer. Light SE-S winds. Temperatures varying from upper 60s to lower 70s at highest elevations to the upper 70s to lower 80s.
Tuesday Night Into Wednesday Morning
Partly cloudy. Areas of dense valley fog. Winds S to SSW at 5-10 mph, with some higher gusts, on mid-upper elevation mountain ridges. Temperatures varying from the 50s to low-mid 60s ( coolest in mountain valleys ).
Wednesday Afternoon
Partly cloudy. Hazier. A chance of hit-miss showers & thunderstorms. Winds SSW-SW 5-10 mph, with higher gusts. Temperatures varying from lower 70s at highest elevations to the upper 70s to low-mid 80s.
Wednesday Night Into Thursday Morning
Partly cloudy. Chance of an evening shower or storm. Areas of dense valley fog. Winds SSW-W at 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures in the upper 50s to mid-upper 60s.
Weather Discussion ( Brief Break )
( Cumulus congestus ) and other forms along an orographic wave line
High Knob Massif Webcam – University Of Virginia’s College At Wise
Except for lingering orographic clouds, a push of much drier air finally made it into the Cumberland Mountains during mid-late afternoon hours of Sunday ( Aug 21 ).
Day-time MAXS varied in the 60s to lower 70s ( 72.8 degrees officially in Clintwood ).
High Knob Massif Webcam – University Of Virginia’s College At Wise
Rainfall was enough to force strong rises on steep creeks draining the High Knob Massif, which will remain swift into Monday before diminishing.
Big Stony Creek of High Knob Massif – Stream Level August 15-21, 2016
A water level rise to near the Red Alert Stage on Big Stony Creek is a good indicator for other steep creeks draining the high country, where this event has pushed 2016 precipitation totals into the 45.00″ to 50.00″ range ( 18.00-20.00″+ during Summer 2016 ).
Refreshing Air Begins To Arrive – Late Afternoon on August 21, 2016
The main focus now is on a brief preview of Autumn 2016 with refreshing, cooler air for a couple days before muggy air returns later Wednesday into Thursday. A brief break!
Monday AM ( August 22 ) will feature the coolest conditions at highest elevations, while Tuesday AM ( August 23 ) will be the coolest in mountain valleys.
MIN temperatures will drop into the 50-55 degree range in cooler places into Monday AM ( especially at highest elevations ) as fog develops and becomes dense in many valleys ( especially at lower to middle elevations ).
MIN temperatures will drop well into the 40s within higher valleys by Tuesday AM, with valleys having little to no fog being coolest versus low-mid 50s in valleys that develop fog ( again, fog will become most widespread at the lower elevations ).
Showers & Tropical Downpours In Thunderstorms Will Remain Possible Into Sunday. Much Drier Air & Cooler Temperatures Are Expected Late Sunday Into Monday.
Remain Alert For The Potential Of Strong Rises On Creeks and Ponding Of Water Along Roads And In Typical Low-lying Flood Prone Locations
A significant cold front will be crossing the mountains by late Sunday with showers & downpours in storms possible along and ahead of the front. Much drier, cooler and refreshing air will be transported into the area Sunday Night into Monday.
Overnight Into Saturday Morning
Chance of a local shower; otherwise, partly to mostly cloudy with areas of fog. Humid. Light winds. Temps in the 60s.
Saturday Afternoon
A chance for showers & thunderstorms. Winds SSW-SW 5-15 mph, with higher gusts. Temperatures varying from 60s at highest elevations to the middle 70s to lower 80s.
Saturday Night Into Mid-Morning Sunday
Showers & thunderstorms developing. Locally heavy rain. SW winds 5-15 mph, with higher gusts, on mountain ridges and plateaus below 2700 feet. Winds SW-W at 10-20 mph, with higher gusts, along upper elevation mountain ridges. Temperatures in the 60s.
Sunday Afternoon
Showers & thunderstorms into mid-late PM ( especially along and south of the High Knob Massif ). Locally heavy rainfall. Refreshing air arriving late. Winds becoming WNW to NW 5-15 mph, with higher gusts. Temps varying from 60s in upper elevations to the mid-upper 70s.
Sunday Night Into Monday
Mostly clear. Cooler & refreshing. Areas of dense valley fog. Winds WNW-NNW 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures in the 50s to near 60 degrees ( 50-55 degrees in cooler locations ).
Monday Afternoon
Partly sunny. Beautiful skies & pleasant. Winds NW-N at generally less than 10 mph. Temperatures varying from 60s in upper elevations to the mid-upper 70s.
Cooler mountain valleys, mainly at mid-upper elevations, will drop into the 40s during Monday Night into Tuesday AM ( with somewhat milder low-mid 50s in foggy valleys ).
Weather Discussion ( Refreshing Air )
An update near Midnight on Saturday is for a slowing of the cold frontal passage Sunday, with new model runs being a few hours slower to clear the area than yesterday.
Models have also increased rainfall amounts, such that at least localized high water problems could arise.
NAM 12 KM Model Precipitable Water Forecast At 5 PM Sunday – August 21
The NAM 12 KM Model has the drier air still just northwest of the Virginia-Kentucky border at 5:00 PM Sunday ( above in brown-blue colors ), with timing being near sunset before it really enters the Cumberland Mountains ( below ).
While this could again made it rough on NASCAR fans, it also means that downpours with a heavy rain potential will linger until deep moisture moves southeast.
NAM 12 KM Model Precipitable Water Forecast At 8 PM Sunday – August 21
Given downpours of rain Saturday the potential for strong rises on creeks will need to be monitored, especially if rain becomes heavy and/or prolonged in nature Sunday. Remain alert for ponding of water along roadways and in typical low-lying, flood prone locations.
The European Model, which did very well with placement of heavier rainfall Saturday, is forecasting the heaviest rains to develop Sunday along the front. The latest NAM group have trended that way, so please remain alert as at least local high water problems could arise.
Previous Discussion
Although humidity, showers & downpours in storms will remain possible ( become likely ) into early Sunday AM, the headline making news is a welcomed push of refreshing air poised to engulf this great mountain landscape from Sunday afternoon into Monday. It will feel awesome!
High Knob Massif Webcam – University Of Virginia’s College At Wise
A general 1.00″ to 3.00″+ of rain has fallen across the mountain area this week, with frequent hit-miss showers & downpours in thunderstorms and often spectacular tropical skies.
High Knob Massif Webcam – University Of Virginia’s College At Wise
August 18-19 featured MAX temperatures in the 70s in Norton-Wise, Sandy Ridge, and Clintwood, with 60s at highest elevations in the High Knob Massif.
*A 78 degree MAX in Clintwood on August 19 will be recorded for the 24-hour period ending at 7:00 AM on August 20 ( below ).
National Weather Service Daily Stats For Clintwood
Short-range models continue to show the chance for downpours in showers & thunderstorms Saturday into Sunday Morning, especially along-ahead of a cold front that will finally push away the tropical air and bring simply spectacular conditions to the area for a while.
NAM 4 KM Model Total Rainfall Forecast Into Sunday
The high resolution NAM 4 KM shows hit-miss downpours, with the NAM 12 KM suggesting best coverage toward the south across the Tennessee Valley & Cumberland Plateau into the TN-NC border area.
NAM 12 KM Model Rainfall Forecast Next 48-Hours
Regardless of the eventual coverage, cooler and much drier air will sweep across the Mountain Empire from northwest to southeast beginning about mid-morning to mid-day on Sunday. A most welcomed and long-awaited change.
Showers & Tropical Downpours In Thunderstorms Will Occur At Times Into This Weekend-Early Next Week, With Heavy To Locally Excessive Rainfall Possible
Any thunderstorm at this time of year can turn locally strong to severe through coming days along and in advance of cold fronts. Heavy to locally excessive rainfall will be possible with a nearly stationary boundary across the mountain area Thursday-Friday, and again late in this weekend along a stronger cold front.
Much less humid air is expected to arrive behind the second cold front by August 22-25 ( with much cooler nights ).
Tuesday Night Into Wednesday Morning
A chance of hit-miss showers & thunderstorms; otherwise, partly cloudy. Areas of fog. Winds SW-W 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures in the 60s to lower 70s.
Wednesday Afternoon
Partly-mostly cloudy. A good chance for showers & tropical downpours in thunderstorms. Humid. SW-WNW winds 5-10 mph. Temps varying from lower 70s at highest elevations to the lower 80s ( warmer south toward the Great Valley ).
**Updated Forecast Below**
Overnight Into Thursday Morning
A chance for showers. SW-WSW winds 5-10 mph, with higher gusts, on mid-upper elevation mountain ridges-plateaus. Humid & hazy. Areas of fog. Temps widespread in the 60s to near 70 degrees.
Thursday Afternoon
A good chance for showers & tropical downpours in thunderstorms. WSW-WNW winds 5-10 mph, with higher gusts, on mid-upper elevation mountain ridges-plateaus. Temperatures varying from 60s to lower 70s at highest elevations to the upper 70s to lower 80s ( warmer south into the Great Valley ).
Thursday Night Into Friday Morning
A chance of showers & thunderstorms. Areas of dense fog. Light winds. Temperatures widespread in the 60s.
Friday Afternoon
A good chance for showers & tropical downpours in thunderstorms. Light winds. Temperatures varying from 60s to lower 70s in upper elevations to the middle 70s to lower 80s ( warmer south into the Great Valley ).
Weather Discussion ( Some Changes )
It is clear now that the boundary will stall across the mountain area, with a continued any place and any time type of pattern featuring intervals of showers & tropical downpours in thunderstorms ( as somewhat drier air does work in north toward the Ohio River ).
Developing Cumulonimbus Along Outflow Boundary – August 17, 2016
For the second day out of three another line of thunderstorms moved across the Cumberland Mountains with heavy rain and booming thunder. With locally more than 2.00″ of rain falling during Monday-Wednesday ( August 15-17 ), this increases the concern for too much rain in places through coming days.
*More than a foot and one-half ( 18.00″ ) of rain has fallen in the City of Norton this summer, with locally higher amounts in the area. This also increases the potential for more rapid run-off if heavy rainfall develops or becomes prolonged in nature.
NAM 12 KM Model Total Rainfall Forecast To 8 AM Sunday – August 21, 2016
Heavy rain will be likely along a stronger cold front later Sunday into early Monday, beyond the forecast period above, such that the potential exists for hefty amounts ( at least in places ).
The Bottom Line…The mountain area will have to wait a while longer to enjoy much drier air, with a stalling boundary set to keep showers & tropical downpours in thunderstorms in the forecast into this weekend when a second, stronger cold front will finally push the high dewpoint ( muggy ) air southward early next week.
Stay tuned to NOAA Weather Radio and your favorite media sources for possible warnings and/or advisories that may be needed through coming days.
Previous Discussion
Rainbow Amid Cumulus Over Long Ridge – August 14, 2016
Weather conditions during the past few days have been straight out of “Beauty And The Beast” with a gorgeous rainbow-cumulus combination being captured over the Tennessee Valley Divide, in southern Dickenson County, by Wayne Riner on Sunday, followed by a beast of a squall line that blasted across Lee, Scott-Wise counties into Dickenson and portions of Russell-Buchanan counties on Monday PM.
Turbulent Clouds Develop In Advance Of Squall Line – August 15, 2016
Hundreds of homes lost electricity due to strong winds and lightning hits as the squall line passed. Rainfall was torrential into Lee, Scott, and Wise counties with 1.00″ to 1.50″ occurring within only 30-45 minutes from The Cedars to High Chaparral.
Wes Ward reported 0.61″ of rainfall at the City of Norton Water Plant ( 3.74″ August / 17.78″ during Summer / 39.06″ in 2016 ) as rain did diminish upon crossing the High Knob Massif ( versus double that much along the windward side of the massif ).
University Of Virginia’s College At Wise
The main corridor of thunderstorms developed over the Great Valley on Tuesday afternoon, as we now begin to enter a “any place and any time” type of pattern along a stationary boundary that tries to slip south a bit by late Thursday to reduce storm chances in the Cumberland Mountains for a short period ( with perhaps, more refreshing air being felt briefly on northerly flow ).
Daily August National Weather Service Statistics – Clintwood
While air temperatures have not been even close to those in the Great Valley, where 44 days of 90+ degree heat have been officially recorded for the Tri-Cities, high humidity levels continue to be nearly relentless in all locations.
*Mixing with breezy to gusty winds making the air along and north of the High Knob Massif feel somewhat more refreshing August 16 in wake of the vigorous Monday storms.
National Weather Service Station In Middle Elevations – Nora 4 SSE
Day-time MAXS varied from 70s above 3000 feet to the low-mid 80s across Wise & Dickenson counties ( 85 degrees in Clintwood ) on August 16 versus another blazing day ( with 95 degrees ) in the Tri-Cities of the Great Valley.
NAM 12 KM Model Total Rainfall Forecast – Tuesday AM Run
The first of two cold frontal boundaries begin to have more impact on local weather Wednesday into Thursday, with the potential for locally heavy-excessive rainfall.
NAM 12 KM Model Total Rainfall Forecast – Early Tuesday PM Run
If this first boundary can slip a little south, somewhat more refreshing air will be felt on northerly flow by Thursday PM into Friday morning.
Although I now have that in my current updated forecast, this remains to be seen and will be dependent upon the boundary’s position come Thursday afternoon-evening.
European 51-Member Ensemble MEAN 850 MB Temp Anomaly Forecast – DAYS 6-10
A more consistent trend is the arrival of much less humid air by early-middle portions of next week, in wake of the next cold front, with the biggest differences being felt by night with cooler temperatures ( especially in valleys ). Fingers crossed this trend will continue to hold.
A Hit-Miss Pattern Of Showers & Tropical Downpours In Thunderstorms Will Continue Through This Week
Although the heaviest widespread rainfall is expected along and north of the Ohio River, locally heavy to excessive rain will remain possible in places across the southern Appalachians and Tennessee Valley. A frontal boundary will get closer to the area by mid-late week, with significantly cooler air currently expected in the extended 5-10+ day period from August 19-23+.
Saturday Night Into Sunday Morning
Partly cloudy. Chance of an evening shower or local downpour. Areas of dense fog developing overnight. Winds SSW to SW 5-15 mph, with higher gusts, along middle-upper elevation mountain ridges-plateaus. Temperatures in the 60s to around 70 degrees.
Sunday Afternoon
Partly cloudy. Chance of hit-miss showers & tropical downpours. Thunder possible. Light & variable winds, except SSW-WSW at 5-10 mph, with higher gusts, along highest mountain ridges. Temperatures varying from the middle 70s at highest elevations to the mid-upper 80s.
Sunday Night Into Monday Morning
Partly cloudy & hazy. Chance of an evening shower or local downpour in a thunderstorm. Areas of dense valley fog. Winds SSW to SW 5-15 mph, with higher gusts, along middle-upper elevation mountain ridges. Humid with temperatures in the 60s to around 70 degrees.
Monday Afternoon
Partly cloudy & hazy. Chance of hit-miss showers & tropical downpours. Thunder possible. SSW-SW winds at 5-10 mph. Temperatures varying from the lower-middle 70s at highest elevations to the low-mid 80s ( hotter south, as typical during this entire period, toward the Tri-Cities ).
Monday Night Into Tuesday Morning
Partly cloudy. Chance of hit-miss showers & downpours thunderstorm. Areas of dense fog. Winds SSE-SSW 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges. Humid & hazy with temps in the 60s to lower 70s.
Weather Discussion ( Relief In Sight? )
The air temperature in Clintwood fell quickly from its PM MAX of 85.6 degrees into the 70s amid downpours in storms that developed over the area ( one of several showers during the day-light hours of August 14 ).
Creek With Sediment Following Downpours In Thunderstorms – August 14, 2016
Areas of dense fog developed in mountain valleys into the evening and overnight with temperatures dropping into the upper 60s.
Places receiving rain during the weekend will begin the week with MAX temperatures a bit lower than locations that missed out ( via more insolation being used for evaporation than heating up surfaces ).
Continued high dewpoints making it difficult to really tell much difference in the way it feels, even though air temps will be a little lower in places with ground that got wet during the weekend.
European 51-Member Ensemble MEAN 850 MB Temp Anomaly Forecast – Days 6-10
Multiple runs of the 51-Member European Model Ensemble show that temperatures in the extended 6-10 day period will be dropping to near or a little below average in the region between the Rockies & Appalachians ( much cooler than average air centered over the Dakotas ).
Meanwhile, continued muggy air will support hit-miss showers and tropical downpours in thunderstorms during this week, with a better coverage expected by mid-late week.
Previous Discussion
Beautiful tropical skies have ruled the mountain landscape as a relentlessly long stretch of atypically humid air grips the region. This has produced a hit-miss pattern of showers and thunderstorms throughout the first half of August.
Tropical Skies Above The University Of Virginia’s College At Wise – August 11, 2016
Take the atmosphere over the Gulf & Caribbean and shift it north into the southern Appalachians and these gorgeous tropical skies are the result ( minus the ocean + the mountains ). And with luck, for us, minus the flooding rains creating havoc over Louisiana.
Awesome Sunset Glow On North Edge of Cumulonimbus Anvil – August 12, 2016
While day-time temperatures have been plenty hot enough in the Cumberland Mountains, it’s night-time MINS which have actually been most anomalous versus climatology.
Daily National Weather Service Statistics For Clintwood
The August 1-13 MEAN Daily MAX in Clintwood has been 83.2 degrees, 2.2 degrees warmer than the 1981-2010 average.
The August 1-13 MEAN Daily MIN in Clintwood has been 65.9 degrees, which is 5.9 degrees warmer than the 1981-2010 average.
While the pattern has been warmer than average, nights have been MUCH warmer than average due to relentlessly high dewpoints.
While dewpoints have been in the lower-middle 70s in Clintwood by day, unlike flat terrain, this does not dictate night-time MINS given decoupling of boundary layer winds and development of nocturnal cool air drainage through mountain valleys.
This nice process allows night-time temperatures to drop below what the dewpoints might suggest. Still, despite the terrain driven feature, nights have been much warmer than average given a deep, vertical depth of humid air that limits how much radiation + drainage can cool the air.
Black Mountain MesoNET Daily Statistics
The anomalously humid air is reflected by temperatures at night recorded above 4,000 feet ( above ), where the average August 1-12 MIN has been 64.2 degrees along the crestline of Black Mountain.
Note this LIMITS the diurnal temperature range along these high crestlines, with a August 1-12 MEAN MAX of 76.3 degrees falling only 12.1 degrees to the MEAN MIN of 64.2 degrees. High valleys amid the High Knob Massif consistently being the coolest during this pattern with general MINS in the 60-65 degree range ( away from any moderating influences of larger lakes ).
Moon Rise Above The Cumberland Mountains – August 13, 2016
In honor of the Olympics, the current Gold Metal Count for 90 degree days continues to climb for the Tri-Cities in the Great Valley of the southern Appalachians.
Daily National Weather Service Statistics For The Tri-Cities
*It is interesting to note that in the Tri-Cities the daily departures of both the MAX and MIN are running nearly identical from long-term averages, with the August 1-12 MEAN Daily MAX of 91.7 degrees being +6.6 degrees above average while the August 1-12 MEAN Daily MIN of 69.2 degrees is +6.7 degrees above the 1981-2010 average.
The 90 degree day count for this year remains at 1 for Wise and Clintwood, and at 0 for Nora 4 SSE and elevations above that level ( 2650 feet ). Meanwhile, Grundy has added one more day to make 10 for the Levisa Fork Valley this season.
European 51-Member Ensemble MEAN 500 MB Height Anomaly Forecast – DAYS 1-5
Looking ahead there are finally signs of change showing up in the modeling, with a break down of the heat ridge that is controlling current conditions and keeping flooding rains to the south and west ( above ).
European 51-Member Ensemble MEAN 500 MB Height Anomaly Forecast – DAYS 6-10
Deep moisture along the Gulf will eventually advect toward the north and northeast. While the heaviest flooding rains are currently forecast to fall mostly along and just north of the Ohio River, this will bear watching since the longer the main swirl lingers along the Gulf Coast the better the odds that it could get picked up and advected farther northeast with time ( by mid-late week into next weekend ) than is currently forecast by main models ( some ensembles do show such a scenario as being possible ). Something to watch through coming days in the modeling.
NAM 12 KM Model Total Rainfall Forecast Next 84-Hours
The NAM Model has been wanting to generate a subsidence zone of sinking air adjacent to the main rainfall corridor, keeping amounts very scant across much of central-eastern Tennessee & Kentucky versus the European Model which is allowing for more convection to fire over the region during the next 5 days ( a bigger and more important increase in rainfall does occur on the European during the 5-10 day forecast period as the upper ridge breaks down ).
The Bottom Line…More diversity looks to arise in weather conditions during the second half of August, with a continuation of tropical air and high humidity levels in the short-term ( next 3-5 days ) giving way to chances for more widespread rainfall and cooler air temperatures as upper ridging finally weakens in the 5-10+ day forecast period ( that is the current trend ).
Hit-Miss Tropical Downpours & Thunderstorms Will Continue Through Coming Days With A Threat For Heavy To Excessive Rainfall In Places During The Remainder Of This Week Into Next Week
A jungle-like high water content air mass will continue to grip the mountain region through the foreseeable future, with little relief from high humidity levels. A new surge of tropical moisture from the Gulf of Mexico will combine with an approaching cold front to increase chances for heavy-excessive rainfall, especially from the Cumberland Mountains westward and northward into next week amid a persistent, slow to change weather pattern.
*NOTE – The position of an approaching cold front into next week will determine where the corridor of heaviest rains set up across the region. Different models, and individual ensemble members of the global models, are currently varied on where this will be. Stay tuned for updates.
Overnight Into Wednesday Morning
Humid with areas of dense fog. Small chance of a shower. SSE-SSW winds 5-15 mph, with higher gusts, along middle to upper elevation mountain ridges. Temperatures in the 60s to around 70 degrees.
Wednesday Afternoon
Partly cloudy. Humid. Chance of hit-miss showers and tropical downpours in thunderstorms. Winds SE-S at 5-10 mph, with higher gusts, especially along middle to upper elevation mountain ridges. Temps varying from low-mid 70s at highest elevations to the lower-middle 80s ( hotter south toward the Tri-Cities ).
Wednesday Night Into Thursday Morning
Humid & hazy. Areas of dense fog. Chance of hit-miss showers & tropical downpours ( especially in the evening ). Winds S-SW at 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges. Temperatures varying from the 60s to around 70 degrees.
Thursday Afternoon
Humid & hazy. Hit-miss showers & tropical downpours in thunderstorms. Light & variable winds. Temperatures in the 70s to lower 80s ( hotter south toward the Tri-Cities ).
Thursday Night Into Friday Morning
Humid & hazy. Areas of dense fog. Chance of hit-miss showers & tropical downpours ( especially in the evening ). Winds S-SW at 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges. Temperatures varying in the 60s to around 70 degrees.
Friday Afternoon
Humid & hazy. Hit-miss showers & tropical downpours in thunderstorms. Light & variable winds. Temperatures in the 70s to low-mid 80s ( hotter south into the Tri-Cities ).
Weather Discussion ( Persistence )
Although a break from downpours and hit-miss storms was enjoyed by most on Tuesday, beneath tropical skies, the wet pattern of Summer 2016 shows no signs of letting up with renewed moisture streaming into the Cumberlands during coming days into this weekend-next week.
Break For Most On Tuesday – August 9, 2016
A recap of wetness since July 1 finds more than a foot of rain falling in the City of Norton during the 40 day period, with 10.56″ measured prior to that in May & June. This as downtown businesses clean up from Monday’s flash flood.
A total of 26 of the past 40 days ( 65% ) have
featured measurable rain in the City of Norton.
Summer 2016 Rainfall Total: 17.14″
( 22.64″ of rain since May 1 )
2016 Precip Total: 38.42″
*2016 precipitation totals have topped 45.00″ in wetter portions of the High Knob Massif ( about average for the City of Norton and the High Knob Massif for this point in a year ).
High Knob Massif Webcam – University Of Virginia’s College At Wise
*When SE winds blow skies are often gorgeous in the High Knob Massif area with many wave clouds and other orographic forms.
Tuesday temperatures reached low-mid 80s from Norton-Wise into Clintwood, with 70s amid upper elevations above 3000-3300 feet in the High Knob Massif.
Nora 4 SSE – NWS Station In The Middle Elevations
An official MAX temp of 86 degrees was observed in Clintwood on Tuesday to mark the hottest day in August and the warmest since July 27. While the TRI is going for a Gold Metal in 90 degree days, the count remains at 1 for Wise, Clintwood, and 0 for Nora 4 SSE and the higher terrain above that elevation ( 2650 feet ).
*Just outside the Cumberland Mountains there have been 9 days at or above 90 degrees in Grundy ( Summer MAX 94 degrees ). That is not surprising given Grundy is around 1000 vertical feet lower in elevation than the City of Norton and 1350 feet lower than Wise.
*A steamy, muggy air mass with high dewpoints have made conditions at all elevations feel uncomfortable during this seemingly endless summer.
NAM 12 KM Model Total Rainfall Forecast To 8 AM Saturday – August 13, 2016
While models will continue to struggle to pinpoint where the heaviest rains will fall, a clear shift west has occurred this week with the 51-Member European Ensembles now showing the greatest rain potential from the Cumberland Mountains westward and northward over a prolonged time frame from late week into next week ( a clear persistence pattern signal with very slow changes over time ).
This makes sense given it fits the pattern of Summer 2016, where wettest conditions ( by far ) have occurred along and west to north of the Cumberland Mountain range versus the Tennessee Valley and most of the southern Appalachians.
*The SE flow pattern being less to much less productive than during summers when a wet feedback, instead of drought, is ongoing along eastern slopes of the southern Appalachians ( rains during August hopefully helping to ease the drought in western North Carolina ).
USA Drought Monitor For August 2, 2016
The next drought monitor will be released August 11.
The spotty nature of summer rain in the Tennessee Valley is a major reason for so many 90 degree days from TRI to TYS-CHA ( i.e., Tri-Cities to Knoxville-Chattanooga ), as dryness breeds more dry times and increases heat.
*There was essentially no chance of reaching 90 degrees, officially, from Norton-Wise to Clintwood on Tuesday since a significant portion of insolation ( incoming solar radiation ) was being put into evaporation from vegetation ( transpiration ) and the ground. This was in contrast to the TRI area where much more insolation could be applied to heating up surfaces, that heated the overlying air, instead of running evapo-transpiration processes.
Here we are talking about official, radiation shielded thermometers that make measuring air temperatures in Wise, Clintwood, and the Tri-Cities equivalent to each other. Not to Weatherbug sites, with roof sensors, or other such devices which tend to read in error during a pattern like this.
A forecaster in the Tri-Cities forecasts for the official MAX, and I do the same for Norton-Wise-Clintwood and our higher mountain terrain amid the Cumberland Mountains.
Hit-Miss Tropical Downpours & Thunderstorms Will Continue Through Coming Days
Although the flash flood warning is no longer in effect, please use caution around swift running creeks and watch for ponding of water in low-lying places during the overnight into Tuesday morning.
Issued By Morristown NWSFO
A jungle-like high water content air mass will continue to grip the mountain region through the foreseeable future, with little relief from high humidity levels. A developing disturbance in northern portions of the Gulf of Mexico will be closely watched for possible impacts upon the southern Appalachians by mid-late this week.
Overnight Into Sunday Morning
Hazy & humid. Areas of dense fog. Chance of an isolated shower. Winds NW-NE winds 5-10 mph along mid-upper elevation mountain ridges. Temps in the 60s to near 70.
Sunday Afternoon
Partly-mostly cloudy. Humid. Chance of hit-miss showers & tropical downpours. Thunder possible. NE winds mostly less than 10 mph. Temperatures varying from lower 70s at highest elevations to the lower 80s ( hotter, as is typical, to the south toward the Great Valley and Tri-Cities ).
Sunday Night Into Monday Morning
Hazy & humid. Areas of dense fog. Chance of a shower, especially during the evening. Light winds. Temperatures in the 60s to near 70 degrees.
Monday Afternoon
Partly-mostly cloudy. Humid. Chance of hit-miss showers & tropical downpours. Thunder possible. ENE-ESE winds 5-10 mph. Temperatures varying from lower 70s at highest elevations to the lower 80s ( hotter, as is typical, to the south toward the Great Valley and Tri-Cities ).
Monday Night Into Tuesday Morning
Hazy & humid. Areas of dense fog. Chance of hit-miss showers ( especially along & S-SE of the High Knob Massif ). Winds SE to SSE 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temps in the 60s to around 70 degrees.
Tuesday Afternoon
Partly cloudy. Humid. Chance of hit-miss showers and tropical downpours in thunderstorms. Winds SE-SSE 5-10 mph, with higher gusts, especially along middle to upper elevation mountain ridges. Temps varying from low-mid 70s at highest elevations to the lower-middle 80s ( hotter south toward the Tri-Cities ).
*A heavy to excessive rainfall potential, of a more widespread nature than recently observed, may develop for portions of the southern Appalachians late this week. Stay tuned for updates.
Weather Discussion ( August 1-9 )
A new month has brought little change in the weather pattern, with less heat but continued high humidity to make conditions steamy and uncomfortable.
A total of 24 of the past 38 days ( 63% ) have
featured measurable rain in the City of Norton.
National Weather Service Station at UVA-Wise – Observer Layton Gardner
Conditions in Wise and Clintwood have been very similar, despite the higher elevation in Wise, during the first 6 days of August due to tropical air ( high humidity ) over wet ground with rain falling every day ( although heavy downpours have been hit-miss with rainfall totals locally to 3.00″+ during August 1-6 ).
National Weather Service Station at Clintwood 1 W – Observer Wayne Browning
The only relief, in part, has been in upper elevations of the High Knob Massif where daily MAXS in low to mid 70s have been common at highest elevations ( still with muggy air ) where breezy conditions have helped to some extent.
Doppler Radar Rainfall Estimate For Saturday – August 6, 2016
Tropical downpours Saturday ( August 6 ) were widely scattered with main corridors extending from Coeburn across portions of the Little Stony Creek & Guest River gorges southeast to near the Mendota Lookout Tower, from High Butte southeast over the U.S. 23 corridor ( between MECC & Harvey ) into the Stock Creek Basin and from the Cranks Creek & Stone Mountain WMA’s southeast by Jonesville to northwest of Kyles Ford. Local downpours hit in the City of Norton and near Appalachia.
*Doppler radar tends to under-estimate rainfall totals in these tropical downpours, especially in orographic locations where rising air further adds to their intensity ( rates of rain fall ). This was observed during July across the High Knob Massif, and in the City of Norton, and has continued during this first week of August ( the weather pattern has been the same ).
Doppler Rainfall Estimate – Zoomed In View – August 6, 2016
Some changes begin to show up into mid week as air flow becomes more easterly. An easterly wind in summer often does not have the same effect as during winter, with heavy rain still remaining possible due to convection ( especially daytime instability ) northwest of the Eastern Continental Divide via abundant low-level moisture.
During the orographic forcing season strong air flow tends to dry lower-levels northwest of the Eastern Continental Divide to reduce total rainfall amounts. Strong air flow is generally lacking during the convective season, outside of organized tropical systems that move inland with enhanced pressure gradients to increase winds, such that forecaster’s have to be more cautious ( especially during summers that feature obvious wet feedbacks ) given much more abundant low-level moisture to feed convection.
Throughout the year there also tends to be a secondary zone of enhanced precipitation on easterly air flow trajectories along the east-southeastern side of the High Knob Massif as noted in recent days with heavy rains over northern Scott County ( heavier than was forecast in much of the Flash Flood Watch zone to the east ).
NAM 12 KM Model Total Precipitation Forecast Next 84-Hours
The upcoming extended forecast period will be one to watch as the MEAN of the 51-Member European Ensembles shows a distinct weakness, or break, in the heat ridges that could allow deep, tropical moisture to spread across the region.
European 51-Member Ensemble MEAN 500 MB Height Anomaly Forecast
Southwest North Carolina ( e.g., Lake Toxaway, Highlands, Brevard ) is certainly most favored for excessive rainfall as deep moisture flows north from the Gulf of Mexico, as are eastern slopes of the Blue Ridge, but it can not be ruled out for locations from the Tennessee Valley back across the already wet Cumberland Mountains ( where it would not take as much to cause problems in the Cumberlands ).
Hit-Miss Tropical Downpours & Thunderstorms Will Continue This Week Into This Weekend With A Threat For Localized Water Problems Upon Saturated Ground
A jungle-like high water content air mass will continue to grip the mountain region through coming days. Heavy to locally excessive rainfall will be possible amid a hit or miss pattern Thursday, with more widespread activity possible Friday into Saturday as a front drops into the mountain region.
Remain alert if heavy rain develops over or upstream of your location. Stay tuned to NOAA Weather Radio and your favorite media sources for possible warnings or advisories.
Overnight Into Thursday Morning
Partly-mostly cloudy. Hazy & humid. Areas of dense fog. SE to SSW winds 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges. Temps in the 60s.
Thursday Afternoon
Partly-mostly cloudy. Humid. Chance of hit-miss tropical downpours and thunderstorms. Winds SE-S at 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges-plateaus. Temperatures varying from low-middle 70s at highest elevations to the low-mid 80s.
Thursday Night Into Friday Morning
Mostly cloudy. Chance of showers & thunderstorms. Humid & hazy. Areas of dense fog. Winds SSE-SSW 5-10 mph, with higher gusts, along upper elevation mountain ridges. Temps in the 60s to around 70 degrees.
Friday Afternoon
Showers & downpours in thunderstorms. Torrential local rain. Some storms may be strong to locally severe. Humid. Light winds ( outside storms ). Temperatures varying from low-mid 70s in upper elevations to the low-mid 80s.
Friday Night Into Saturday Morning
Mostly cloudy. Humid & hazy. Areas of dense fog. Small chance of a shower. Winds SW-NW at generally less than 10 mph. Temps in the 60s to around 70 degrees.
Saturday Afternoon
Showers & downpours in thunderstorms. Torrential local rain. Some storms may be strong to locally severe. Humid. Light winds ( outside storms ). Temperatures varying from upper 60s-lower 70s at highest elevations to the lower 80s.
Weather Discussion ( August 2-6 )
Friday Night Update
A steamy ( tropically muggy ) air mass continues to grip the mountain area with locally heavy rains during the past 24-hours, with a notable bias ( to no surprise ) along the Scott County side of the High Knob Massif via E-SE air flow and upsloping into the high country.
High Knob Massif Webcam – University Of Virginia’s College At Wise
Nice fish-tail lenticular clouds developed in the easterly flow across the massif ( above ) during Thursday afternoon-evening.
Scott County VA Automated Rain Gauges
Around 1.00″ of rain fell over the head of Big Cherry Lake basin, on the Wise County side of the massif, but heaviest widespread rains of 1.00″ to 2.00″+ fell in northern Scott County with rising air toward the high country from the NE-SE-S.
*The Camp Rock gauge is not working properly and reads much too low.
Measurable August rain has fallen daily in Clintwood, with 1.19″ measured so far during August 1-5 ( as of the afternoon ).
NAM 12 KM Model Total Rainfall Forecast Next 84-Hours
Models have been slowing the next approaching front, such that drier and less humid air is likely to never make it into the area to any significant extent. The NAM Model now has the lowest dewpoints at the High Knob Massif summit level only dropping to around 61 degrees ( previous days had them falling well down into the 50s ).
The Bottom Line…A continuation of hit-miss showers and tropical downpours, with thunderstorms possible, through the weekend into early next week.
A developing low pressure over the northern Gulf of Mexico will still bear close watching for a possible influence on the southern Appalachians during the extended 5-10+ day period ( i.e., the mid to later portion of next week ).
Tropical Skies Above Little Stone Mountain Gap – Looking Toward Norton
Every day some place, or places, takes a torrential rainfall hit with St. Paul, Dante, and Castlewood being the targets during August 2. Fast forward a day to August 3 and it was the City of Norton, Big Cherry Lake, and other local places in Wise, Scott, Lee, Dickenson, and Russell counties.
Downpours on August 3 dropped 0.50-1.00″ of rain in 30 minutes or less, characteristic of tropical downpours ( with little to no lightning ).
Previously, on August 1, a gully washing downpour hit Wise with ponding of water along roads and increased run-off. In jungle-like fashion it left steamy looking fog and a bounty of haze in its wake.
Nora 4 SSE on Long Ridge – Weather Observations during July 27-August 2
A wet feedback is influencing weather conditions across Wise and Dickenson counties, in particular, with another 0.69″ added onto the above observations for Nora 4 SSE on Long Ridge into morning hours of August 3 ( making 4.90″ of rain during the past 7 days ).
Ditto for the City of Norton, which I will update later Thursday.
MAX temperatures have not climbed above the low-mid 70s in upper elevations of the High Knob Massif since July 27, amid this wet pattern featuring abundant clouds and hit-miss tropical downpours.
NAM 4 KM Model Total Rainfall Forecast To 8 AM Saturday – August 6, 2016
The pattern does not change into this weekend, with even an increasing chance for tropical downpours and storms as the next frontal boundary drops into the mountain region.
By next week an area of low pressure along the northern Gulf is being forecast by the European Model to develop, with abundant moisture that will bear close watching across locations from the Deep South into the southern Appalachians ( stay tuned for updates on that ).
Hit-Miss Tropical Downpours & Thunderstorms Will Continue This Week With A Threat For Localized Water Problems In A Steamy, Jungle-like Air Mass
A jungle-like high water content air mass will continue to grip the mountain region through coming days. Heavy to locally excessive rainfall will be possible in places amid a hit or miss pattern.
Remain alert if heavy rain develops over or upstream of your location. Stay tuned to NOAA Weather Radio and your favorite media sources for possible warnings or advisories.
Overnight Into Mid-Morning Tuesday
A chance of showers & thunderstorms, especially toward morning. Areas of dense fog. Light winds, except SW-W at 5-10 mph along upper elevation mountain ridges. Humid with temperatures in the 60s.
Tuesday Mid-Morning Through The Afternoon
Showers & downpours in thunderstorms becoming likely. Locally heavy rainfall. Winds becoming northerly at less than 10 mph ( outside storms ). Temperatures varying from upper 60s to lower 70s at highest elevations to the mid 70s to around 80 degrees ( hotter south into the Great Valley ).
*This period will bear watching for prolonged dense fog formation across higher elevations amid the moisture laden atmosphere.
Tuesday Night Into Wednesday Morning
A chance of showers & thunderstorms. Areas of dense fog. Winds N-NE at 5-10 mph, with higher gusts, along middle to upper elevation mountain ridges. Humid. Temps in the 60s.
Wednesday Afternoon
Partly cloudy. Chance of showers and thunderstorms. Winds E-NE at 5-10 mph, with higher gusts ( especially on higher mountain ridges ). Temperatures varying from the upper 60s to lower 70s at highest elevations to the upper 70s to middle 80s ( hotter south into the Great Valley ).
Wednesday Night Into Thursday Morning
Partly cloudy. A chance of showers & thunderstorms, especially during the evening. Areas of dense valley fog. Winds SSE-SSW at 5-10 mph on mid-upper elevation mountain ridges. Temps in the 60s.
Weather Discussion ( July 31-Aug 4 )
A tropical, jungle atmosphere has a firm grip upon the Cumberland Mountains where hefty July and summer rainfall totals have been observed.
Tropical Sky Above Powell Valley of High Knob Massif
Although July 2016 was generally 2 to 4 degrees Fahrenheit warmer than average across the region, differences in the actual observed conditions were simply amazing.
July 2016 Climate Data – University Of Virginia’s College At Wise
MEAN July temperatures of 73.6 degrees in Wise ( above ) and 73.2 degrees in Clintwood ( below ) featured one day during the month at or above 90 degrees amid above average rainfall.
July 2016 Climate Data – Clintwood 1 W NWS Station
The MEAN July temperature in the Tri-Cities was 78.6 degrees, making it the second hottest on record amid dryness with only 2.89″ of total rainfall.
July 2016 Climate Data – Tri-Cities, Tennessee NWS Station
To put the above into better perspective, had the Tri-Cities experienced the same temperatures as Wise and Clintwood the month would have been cooler than average by 1.0 to 1.4 degrees Fahrenheit.
July 2016 Climate Data – Black Mountain MesoNET
Heading up into the high Cumberlands the MEAN July temp at the 4031 foot level on Black Mountain was 69.4 degrees, which would have ranked as the COLDEST on record in the Tri-Cities ( even though it was significantly warmer than average for July at this high elevation ). Rather amazing when you consider it by the actual numbers observed!
Dawn of Late Summer at Big Cherry Lake of High Knob Massif
Dr. Phil Shelton, professor emeritus extraordinaire at the University Of Virginia’s College At Wise, recently found the Hermit Thrush ( Catharus guttatus ) for the 4th consecutive year atop the High Knob Massif.
This means that this northern bird species is nesting atop the high country in the massif along with many other birds, such as the Veery Thrush ( Catharus fuscescens ), possessing northern affinities.
Temperatures on northern slopes in the massif are coolest, and tend to be cooler than exposed summits and open expanses around larger lakes.
Gorgeous Tropical Skies Above Big Cherry Lake of High Knob Massif
Although the lake level at Big Cherry is around 3117.0 feet above sea level, down about 3 vertical feet, it is not due to dryness and drought but rather to a large amount of water that has been released from the Dam during the past 4-6 weeks to help augment flow on the Powell River as it enters much drier terrain toward the Virginia-Tennessee stateline.
A key factor in relatively cooler summer conditions in upper elevations of the Cumberlands being abundant clouds and wetness, with the MEAN July rainfall recorded during the past 8-years being 7.03″ at Big Cherry Lake Dam prior to July 2016 which has been significantly wetter.
A total of 8.98″ of July rainfall was measured on the north base of the High Knob Massif at the City of Norton Water Plant ( 14.04″ since the beginning of Meteorological Summer on June 1 ).
Only 2.89″ of July rainfall ( 5.02″ since June 1 ) was measured officially in the Tri-Cities, Tn., aiding the large number of 90+ degree days observed due to dry ground and limited moisture for evaporation and evapotranspiration processes which help cool the air and support more cloud formations and showers-thunderstorms ( also cooling air ).
The sun does not heat air directly. Instead the sun heats surfaces of the earth which then heat the overlying air. If the ground is dry, with limited moisture for evaporation ( which uses up some of the insolation ), then a positive feedback for heating ( and often dryness ) develops during the summer season to help promote higher temperatures.
NAM 4 KM Model Total Rainfall Forecast To 8 AM Thursday – August 4, 2016
Looking ahead there is little change in the forecast setting this week, with short-range models continuing to look like they have a bad case of the measles as guesses are made about where more tropical downpours may fall ( a brief break in the action may occur during mid-week if the NE wind flow can advect in more stable air…stay tuned ).
A gully washing downpour struck UVA-Wise Monday afternoon, August 1, with torrential rain like might be seen in the Amazon, spiced with lightning-thunder, before it quickly abated. This caused ponding of water along numerous roadways in Wise.
The Bottom Line…A jungle-like environment will continue to support hit-miss tropical downpours above the wet terrain, with more organized action possible at times…especially later in the week and weekend as another front stalls across the region.
