Mountain Area Forecast ( June 28-30 )

Overnight Into Tuesday Morning

Hazy & humid with light rain & drizzle.  Areas of dense fog, most widespread in locations along-north of the High Knob Massif & Tennessee Valley Divide.  Winds NW-NE at 5 to 15 mph along mid-upper elevation mountain ridges.  Temperatures widespread in the 60s.

Tuesday Afternoon

Partly sunny.  Small chance of a localized shower.  Skies becoming blue with decreasing haze late.  NW winds 5 to 15 mph.  Temps varying from low-mid 70s to lower-middle 80s ( coolest at highest elevations ).

Tuesday Night Into Wednesday Morning

Mostly clear.  NNW-NNE winds decreasing to generally less than 10 mph by morning on mountain ridges.  Temps from lower 50s to lower 60s.

Wednesday Afternoon

Partly to mostly sunny.  Beautiful blue skies with northerly winds 5-10 mph.  Temperatures varying from 60s at highest elevations to the middle 70s to around 80 degrees.

Wednesday Night Into Thursday Morning

Mostly clear.  Chilly in mountain valleys.  Light N-NE winds.  Temperatures varying from upper 40s to mid 50s in cooler mountain valleys to the upper 50s to lower 60s.

Thursday Afternoon

Partly cloudy.  Pleasant.  Small chance of a shower or thunderstorm.  Northerly winds generally around 10 mph or less.  Temperatures varying from 60s to lower 70s at highest elevations to the upper 70s to lower 80s.

A stormy weather pattern is likely to develop by the Independence Day Holiday Weekend into next week as heat & humidity increases to establish a temperature-moisture gradient across the region.  A heavy to locally excessive rainfall potential is being monitored for portions of the Mountain Region.  Stay tuned for later updates.

Weather Discussion ( June 27-30 )

Wednesday Evening ( June 29 ) Update

A gorgeous late June air mass graced the Cumberlands during June 29, with 50s to lower 60s in the morning giving way to pleasant 70s to around 80 degree afternoon temps.

Latest model runs are showing a better Holiday weekend for the Mountain Empire than in previous days, but a chance of hit-miss showers and thunderstorms will exist.

The operational European Model has come more in line with the MEAN of it’s 51-Member Ensemble group, with a shift to the north with the heaviest rainfall axis into next week.

While this might have been predicted from feedback of drought developing across the Tennessee Valley and parts of the southern Appalachians, it remains in flux and the Cumberland Mountains remain in play for the potential of heavy to excessive rainfall amounts next week ( along with locations to the north into the Ohio Valley & West Virginia ).

This recent trend does not bode well for flood ravaged West Virginia, with many praying for this current drying period to continue through the extended.

The Updated Bottom Line…While a chance for showers and thunderstorms will return from Thursday-Friday through the Holiday Weekend, recent model runs are not looking as wet as in previous days.

A very stormy period continues to be likely in the extended 5-10+ day interval, with a heavy to excessive rainfall potential looming for portions of the Ohio Valley and Appalachians.  Again, at this time, the precise corridor of main impact can not yet be determined despite a general shift northward by MEAN model guidance away from the Tennessee Valley ( the Cumberland Mountains remain in a potential target zone of training storm clusters ).

Stay tuned for later updates as models continue to work to figure out the pattern into the first week of July 2016.

Previous Discussion

Reference My 062716 Forecast Discussion for recent data on the West Virginia flood disaster.

While the terrible June 22-23 flood is being called a 1000 year event, it is important to note this may be true only in the corridor impacted. Many severe flood events have occurred in the Appalachians, with one of the worst and most widespread events striking during April 1977 ( 40 years from this coming April ).

Reference Flood Of April 1977 In The Appalachian Region for details on a major event that was much more widespread in coverage along the Appalachians, with 47 counties declared Federal Disasters along with 22 fatalities.  Many communities  across Wise, Lee, Dickenson, Buchanan, Scott, Bell, Harlan,  Letcher and Pike counties were devastated in addition to numerous communities in southwestern West Virginia.

Showers and downpours in thunderstorms developed to begin the new work week on June 27, with local rainfall totals topping 1.00″ in places.  Afternoon cloud bases lowered to obscure high ridges amid the high country.

While light rain, drizzle and low cloud bases linger tonight a drier and simply gorgeous stretch of weather conditions is expected to rule the mountain landscape during mid-week.

This period of weather should be enjoyed.

It is becoming clear in the modeling that another stormy period is upcoming as a temperature-moisture gradient again sets up a boundary along which clusters of showers and downpours in thunderstorms will roam.  Since the air mass to the south has not changed, this is worrisome given a high precipitable water air mass will be nearby.

This will be more of a WNW-ESE or W-E setting with thunderstorm clusters moving along the gradient.  What is yet to be determined is exactly where the gradient sets up.

The early trends seem to be ones to focus more on the southern Appalachians and Tennessee Valley versus locations flood ravaged in SE-Central West Virginia.

However, it is just too early to tell for sure.  More should be known in a few more days as initial action begins to form by late in the work week and the weekend.

The Bottom Line…A simply gorgeous mid-week stretch of weather conditions will give way to another stormy period by the Independence Day Holiday & next week.  The threat for heavy to excessive rains could again arise as a gradient sets up across the region with return of a high moisture content air mass, but the location of this can not yet be determined.

Stay tuned for updates in coming days.

Mountain Area Forecast ( June 26-28 )

ALERT For The Potential Of Torrential Local Rainfall Monday Into Monday Evening.  Some Storms Could Be Strong To Locally Severe.

The Storm Prediction Center Has Issued A Marginal Risk For Severe Thunderstorms Across The Mountain Area For The Period Between 8 AM Monday and 8 AM Tuesday ( June 27-28 ).

Overnight Into Sunday Morning

Mostly clear.  SE winds becoming SSW-SW at 5-10 mph, with higher gusts, along upper elevation mountain ridges.  Mild with temperatures from mid-upper 50s in cooler mountain valleys to the mid-upper 60s.

Sunday Afternoon & Early Evening

Partly cloudy.  More humid and hazier.  Chance of afternoon and evening showers or thunderstorms.  Local downpours.  Light S-SW winds generally less than 10 mph outside of any storms.  Temperatures varying from 70s in upper elevations to the lower-middle 80s.

Late Sunday Night Into Monday Morning

Partly to mostly cloudy.  Hazy & humid with areas of fog.  Chance of a hit-miss shower or thunderstorm.  Winds SSW to WSW at 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges & plateaus.  Warm.  Temps widespread in the 60s to around 70 degrees.

Monday Afternoon

 Showers & downpours in thunderstorms likely.  Some storms could be strong to locally severe.  Light & variable winds outside of storms.  Temperatures varying from the mid-upper 60s to the mid-upper 70s ( coolest at highest elevations ).

Monday Night Into Tuesday Morning

Hazy & humid with a chance of showers & thunderstorms.  Winds becoming WNW to NW at 5-15 mph along mid-upper elevation mountain ridges.  Temps widespread in the 60s.

Weather Discussion ( June 22-28 )

Thoughts, Prayers, and Condolences to families and friends losing loved ones are given to those impacted last week.

A preliminary signal for this larger event was observed in extreme SE Kentucky when flash flooding damaged 75-100 homes in Harlan County during June 21-22.  Rainfall totals up to 6.02″ were hand-measured 3 miles north of Harlan versus only 0.84″ atop Kentucky’s highest peak on Black Mountain ( Harlan 24 E ).

This skewed ( from climatology ) gradient of rainfall ( with less atop Kentucky’s highest and wettest terrain ) was again played out during the second and much larger event during June 23 when rain totals in the Greenbrier Valley ( for example ) were much greater than amid West Virginia’s wettest and highest terrain ( from the Pickens-Kumbrabow State Forest to Snowshoe-Canaan Mountain ).

While the pattern leading up to both of these episodes was well forecast, and I was both concerned and very aggressive with the forecasting, it must be understood that a pinpoint of where flash flooding or wind damage will occur is not typically possible in a convective pattern until after the thunderstorms actually develop on radar.

The high-resolution NAM 4 KM Model run at 8 PM on Wednesday, June 22, did the best job of forecasting rainfall with a MAX of up  10.00″+ over West Virginia ( just not over the counties where such amounts actually fell ).  It did have the heaviest rainfall zone, in general, properly placed on this particular model run.  By contrast, the HRRR Model in hours leading up to the main disaster had the heaviest rain forecast over northern West Virginia ( north of the Greenbrier ).  The centroid of actual convection building more to the southwest and south with the initial Mesoscale Convective Complex ( producing high winds ) than the HRRR predicted during hours after the 00z June 23 ( 8 PM June 22 ) initialization.

The 1981-2010 Annual Precipitation MEAN is listed as 39.30″ for White Sulphur Springs ( the above being for 1971-2000 ).

An excellent example of how convection skews settings is that the Covington, Virginia to White Sulphur Springs, West Virginia corridor is typically among the driest in both states over the long-term mean ( average annual precipitation in the 37.20″ to 40.40″ range ).

During the January to May period of 2016 just over 15.00″ of total precipitation had been measured in Covington, with around 16.51″ in White Sulphur Springs ( only around half as much as in wetter portions of the High Knob Massif  ).

During this event, around 3 times as much rain fell on White Sulphur Springs in just 12 to 24 hours as typically falls during an entire June ( 3.51″ ) at that location.

The 1981-2010 Annual Precipitation MEAN is listed as 37.80″ for Covington Filter Plant ( the above is for the 1971-2000 period ).

During the convective ( thunderstorm ) season it becomes important to understand that places which are the wettest  ( climatologically over the longer term ) may not receive the most rainfall, especially during any particular event when any place ( even those typically among the driest ) becomes a potential target for heavy to excessive rain.

An interesting, perhaps ironic, twist to these terrible events being that this excessive rainfall fell amid a large region of developing drought in the eastern USA ( particularly along much of the Appalachian chain ).

A drier air mass and welcomed break from the stormy pattern was observed Friday-Saturday ( June 24-25 ).

Focus now shifts toward the next weather systems which will be impacting the mountain region from late Sunday into the upcoming work week and first week of July.

The Storm Prediction Center has issued a marginal risk for severe thunderstorm development across the mountain region for Monday into early Tuesday.

A threat for heavy rainfall, which may be implicit but not an actual factor in severe thunderstorm criteria, may end up being the most important concern given that another high precipitable water air mass will be in place during Monday-Tuesday ( June 27-28 ).

I may issue an ALERT for this Sunday Night if I think this will be a significant concern for June 27-28 ( with another pre-signal being how convection may or may not form by later Sunday into Sunday evening as a litmus test ).

I will say that the pattern ahead remains a concern, with persistence of a WNW flow across the region and a gradual amplification once again.

This causes a cooling trend across much of the northern half of the nation and a shift to heat dome cores over Texas and the Pacific Northwest and West Coast of the USA.

This once again strengthens a north to south temperature gradient across the eastern USA.

The pattern upcoming, therefore, will feature hot and very humid air to the south and unseasonably cool, drier air to the north with a battle zone in between featuring an array of showers and downpours in thunderstorms.

The job for regional forecasters in days ahead, especially during the extended 5-10+ day period, will be to determine where this battle zone sets up shop ( likely with waxs and wanes in precise positioning ) since it will be the zone that could again feature heavy to excessive rainfall amounts.

Mountain Area Forecast ( June 22-23 )

ALERT For Severe Thunderstorm Development During Wednesday-Thursday.  A Major Wind Damage Event Is Likely Within Or Close To The Cumberland Mountains And Mountain Empire

Wind Damage, Large Hail, Vivid Lightning & Flooding Rainfall Will Be The Main Severe Threats.  This Could Result In Power Outages For Impacted Locations.

Updated at 6:00 PM Thursday – Individual supercell thunderstorms across Kentucky are forming into a squall line that will be the main feature of concern Thursday Evening-Night for counties across the Cumberland Mountains and Mountain Empire

A stormy weather pattern, anchored by a major heat dome to the west, is taking shape with strong-severe storms becoming likely during the Wednesday-Thursday period as part of a major severe weather outbreak.

Mesoscale Convective Systems ( large thunderstorm clusters ) are expected to develop, with potential for Derecho or near-Derecho Formation ( a long-lived wind damage producing system ).

More localized strong-severe thunderstorm development will also exist as dewpoints and instability increase through Wednesday. Please stay tuned to NOAA Weather Radio for possible watches and/or warnings that will be likely.

Tuesday Night Into Wednesday Morning

A chance of showers & thunderstorms.  SW-W winds 5-15 mph, with higher gusts, on mid-upper elevation mountain ridges.  Temperatures widespread in the 60s.

Wednesday Afternoon Into Wednesday Night

Showers & thunderstorms likely.  Some storms could be strong to severe with wind damage and flooding rainfall.  SSW-W winds 10-20 mph, with higher gusts.  Temperatures varying from upper 60s-lower 70s across highest elevations to the upper 70s to lower 80s.  Very humid.

Thursday Morning Into Thursday Night

Showers & thunderstorms likely.  Some storms could be strong to severe with wind damage and flooding rainfall.  SW-W winds 10-20 mph, with higher gusts.  Temperatures varying from 60s to low 70s in the morning to the 70s to lower 80s into the afternoon.  Very humid.

Although details remain to be worked out, I have significant concern that a flash flood setting could also emerge across portions of the mountain area.

*NOTE that high-resolution models change radically due to the nature of convection over short-time periods.  Therefore, it is most important to FORECAST THE PATTERN in a setting like this and not depend upon any given model run.

Weather Discussion ( June 21-23 )

Early Thursday Afternoon Update

A Tornado Watch is now in effect for Dickenson and Buchanan counties until 10:00 PM Thursday ( June 23 ).

Remember that a WATCH means conditions are favorable for tornadoes IN AND CLOSE TO the watch area.

The atmosphere today is so unstable that there has been explosive thunderstorm development during the mid-afternoon, with radar indicating cloud tops soaring to more than 60,000 feet into the steamy atmosphere.

The Storm Prediction Center indicated that a watch would be coming during the early afternoon, which is no surprise given increasing instability ( high CAPE-moisture values to go along with SHEAR ) in presence of outflow boundaries generated by the overnight Thunderstorm Complex that passed just north and northeast of the Cumberlands.

More than 30,000 homes & businesses lost electricity across West Virginia on the AEP Network overnight into Thursday morning.

Meanwhile, a flash flood emergency has been declared in portions of the eastern mountains, from Richwood in Nicholas County into the Greenbrier County area.  Outside of that area at least 1 person has reportedly been swept away by flooding in West Virginia.  In fact, WSAZ-TV reports at least 30 flood rescues in progress across the state at 5:45 PM Thursday.

The updated risk region has the northern end of the Cumberland Mountains touching the Enhanced Risk.

Early Thursday Overnight Update

Counties along the Virginia-Kentucky border once again took the burnt of strong-severe thunderstorms Wednesday, with prolific lightning, heavy rain, and local wind damage.

Wednesday ( June 22 ) MAXS remained in the 70s in Norton-Wise and Clintwood ( 75 degree MAX ) as debris cloudiness coming in from thunderstorms toward the northwest, and subsequent storm development, held air temperatures down versus locations south toward the Tri-Cities ( where 85 to 90 degrees was common ).

A major thunderstorm cluster that is near the Maddox definition for a true Mesoscale Convective Complex or MCC formed Wednesday evening across the Upper Midwest.

Note the dramatic increase in size as denoted by colorized Infrared Satellite Imagery showing the expansion of cold cloud tops which are associated with deep convection ( thunderstorms ).

These are the most prolific lightning producing systems on planet Earth, so a tremendous “light show” is ongoing.  “Heat” lightning will be seen far to the south as the complex drops farther S-SE.

For some reason, perhaps some contamination of sounding data, short-range models like the HRRR resolved the storms better up until the 00z ( evening ) data was ingested.

Recent HRRR future Doppler forecast’s have lost the storm line over Illinois into Indiana.  So it becomes more “interesting” with respect to how far south and southwest the MCS-MCC develops versus a more eastward trend currently forecast by the HRRR.

Climatology shows that such systems typically build farther south and southwest ( toward the inflow side ) and turn more right of the general flow field over time ( as I noted previously, the MesoHigh or cold pool forces system relative low-level convergence to help dictate the propagation over time ).  The important area that HRRR recent runs have missed, over Illinois into Indiana, being the point outward from which there is beautiful upper divergence as seen on above Infrared images.

Numerous tornado and many wind damage reports have been documented from Illinois and Indiana into Ohio.

My thinking remains essentially unchanged, as despite what happens into Thursday morning it is very likely that new development forms during the afternoon-evening to renew the severe threat ( with wind damage and flooding rainfall remaining the primary threats outside of always dangerous lightning and localized hail ).

An outflow boundary from this MCS-MCC ( near Derecho ) system will act as a notable focus for new development Thursday, amid a very unstable air mass with high CAPE and instability.  This will likely, unless the area is very lucky, lead to a more widespread severe event Thursday versus that experienced Wednesday.

Continue to stay tuned to NOAA Weather Radio and your favorite media sources for more watches and/or warnings which will be likely once again Thursday.

Previous Discussion

Reference my 062116 Forecast Discussion for more details.

Strong to severe thunderstorms impacted portions of the mountain region during Tuesday as instability & moisture increased along and ahead of a surface frontal boundary.

Factors conducive to a major severe weather outbreak are now becoming better defined, with a serious threat of one or more clusters of severe thunderstorms.

Potential for a Derecho is increasing, with a major wind damage event coming close ( to the north ) or hitting the Cumberland Mountains by Thursday.

Meanwhile, a lead thunderstorm cluster currently from Iowa into Illinois could drop southeast and trigger strong to severe thunderstorm development Wednesday in advance of the next major storm complex.

One reason I have become very aggressive with this forecast is that even IF the main Derecho complex misses hitting the area directly, a major outflow boundary is likely to act as a focus for new severe thunderstorm development Thursday toward the inflow side ( warm-very unstable ) of the system across eastern Kentucky and southwestern Virginia.

Such a setting also increases the potential for flash flooding to develop, since a tendency for back-building convection is climatologically favored amid a more westerly 850 MB flow field ( beneath WNW flow aloft ) along any boundaries that are present to act as a low-level focusing mechanism ( in combination with terrain features ).

*Some homes were flooded in Harlan County during Tuesday amid an air mass that possessed a lower total water content than that expected Wednesday into Thursday.

The Bottom Line…A serious severe weather outbreak is likely to develop Wednesday into Thursday, impacting locations within or very close to the Mountain Empire.

Please stay tuned to NOAA Weather Radio and your favorite media sources for updates and likely watches and warnings that will be needed.

Mountain Area Forecast ( June 20-22 )

Reference My Latest Forecast Update At This Link

ALERT For Potential Of Severe Thunderstorm Development During Tuesday And Wednesday

Wind Damage, Large Hail, Vivid Lightning and Flooding Rain Will Be The Main Severe Threats ( This Could Result In More Power Outages For Impacted Locations ).  This Threat May Extend Into Thursday ( June 23 ).

A stormy weather pattern, anchored by a major heat dome to the west, is taking shape with the potential for strong-severe storms increasing Tuesday into Wednesday.

One or more Mesoscale Convective Systems ( large thunderstorm clusters ) are expected to develop from Tuesday into Wednesday, with some potential for Derecho Formation ( a long-lived wind damage producing system ).  Exact location and track of these thunderstorm clusters remains uncertain and will need to be predicted once storms develop on Doppler radar.

More localized strong-severe thunderstorm development will also exist as dewpoints and instability increase from Tuesday through Thursday.  Please stay tuned to NOAA Weather Radio for possible watches and/or warnings that may be needed.

Remainder Of Monday Afternoon

Partly cloudy.  Small chance of a shower or thunderstorm.  Winds W-NW at 5-15 mph, with higher gusts along middle to upper elevation mountain ridges.  Temperatures varying from low-mid 70s at highest elevations to the lower-middle 80s ( warmer south toward the Tri-Cities ).

Monday Night Into Tuesday Morning

Partly to mostly clear during the evening, then increasing clouds overnight into morning with a chance of showers & thunderstorms.  Winds SW to W at 5-15 mph, with higher gusts, along mountain ridges-plateaus below 2700 feet.  WSW-WNW winds 10-20 mph, with higher gusts, along mountain ridges above 2700 feet.  Temperatures varying from middle-upper 50s to the mid-upper 60s ( coolest in mountain valleys with light winds ).

Tuesday Afternoon

Showers & thunderstorms becoming likely.  Some storms could be strong to severe.  SW-WSW winds 10-20 mph, with higher gusts.  Temperatures varying from the upper 60s to the upper 70s to around 80 degrees ( coolest at the highest elevations ).

Tuesday Night Into Wednesday Morning

A chance of showers & thunderstorms.  Some storms could be strong to severe.  SW-W winds 10-20 mph, with higher gusts, along mid-upper elevation mountain ridges.  Temps widespread in the 60s.

Wednesday Morning Into Wednesday Evening

Showers & thunderstorms likely.  Some storms could be strong to severe.  SSW-W winds 10-20 mph, with higher gusts.  Temperatures varying from upper 60s-lower 70s across highest elevations to the upper 70s to lower 80s.

The risk for a large thunderstorm complex will be highest from Tuesday Night into Wednesday, with initial development expected to be upstream of the Appalachians followed by movement toward the mountains from the northwest.  Timing and trajectory ( track followed by the storms ) will have to be determined as the event gets closer.  Stay tuned for updates.

Weather Discussion ( June 18-22 )

A lovely stretch of June weather during the Father’s Day weekend is expected to end abruptly as the risk for showers and powerful thunderstorms increases significantly into Tuesday and Wednesday ( June 21-22 ).

My friend Wayne Riner captured a gorgeous sunrise above Long Ridge, in southern Dickenson County, to begin the work week.

With some vertical cloud development a hit-miss, localized shower or even thunderstorm can not be completely ruled out through this afternoon-early evening.  Chances remain low today and tonight in comparison to Tuesday when odds for shower-thunderstorm development ramp upward.

The entire pattern is being anchored by a heat dome centered over the southwest-central portion of the USA.

The initial increases in the risk for strong-severe storms will develop as a cold front sags southward into the region during Tuesday, providing a low-level focus for convection as the upper level flow diverges and streams across the Mountain Empire from the northwest.

However, what is really catching my eye is a surge of blazing heat that will be developing into Wednesday, setting up a huge temperature-dewpoint gradient from southwest to northeast across the Great Lakes and the Middle Atlantic region ( below ).

By early Wednesday a 20+ degree Celsius ( 38+ Fahrenheit ) temp gradient is being forecast between the Upper Midwest and eastern Great Lakes-Northeastern USA.  The thermal zone being defined well on the above model ( even though exact placement of its axis may vary some from what any given model is currently showing ).

 While thunderstorms Tuesday could become strong to severe amid a general northwest flow setting, and must be respected, the synoptic or large-scale pattern becomes even more favorable for large thundrstorm cluster ( complex ) development by Tuesday Night into Wednesday.

It is during this time that potential for a Derecho or near-Derecho cluster of thunderstorms will increase.  One reason for this is the presence of dry mid-level air ( shown above ) which research has shown to be a KEY factor in supporting wind damage producing bow echoes-Derechos.  The dry air promotes formation of a strong MesoHIGH or cold pool via evaporation aloft.  The cold pool acts to sustain the system by continuous formation and generation of low level convergence relative to the convective system ( evaporation into drier air aloft adding to downdraft momentum by making the air more dense ( heavy ) and aiding its plunge to earth ).  Terrain drag at the surface with downward and outward spreading air forces convergence ( or piling up ) of low-level air to drive and renew upward vertical motion ( lifting moist, unstable air to create condensation and complete a cyclic feedback process ).

The horizontal temperature gradient at the surface being a factor to strengthen winds aloft ( dictated by the thermal wind equation and the isallobaric component of the ageostrophic wind equation ) during any time of year, adding to the potential for downward momentum transfer to the surface in organized downdrafts.

It can not yet be known if the Mountain Empire will take a direct hit from a complex.  While large storm clusters do tend to move along 1000-500 MB thickness lines, and the 850-300 MB MEAN cloud-layer wind field, the ultimate movement is often dictated by the greatest system-relative low-level convergence ( forced by the cold pool ) which may or may not be in the same direction as the low-level jet.

*This may further be modulated by Supercell’s embedded within the MCS which adds additional complexity to propagation as has been suggested by Stephen Corfidi at the Storm Prediction Center.

Since the low-level jet often streams into such a system from the southwest, it is not uncommon for development to focus on the inflow side of the system which is often the southwest-southern, or forward, flank for a cluster embedded in NW-SE ( downshear ) flow.  While this is, of course, very important an assemblage of many MCS’s illustrates that ultimate movement is forced most by the cold pool produced by low-level convergence relative to the system ( and apparently modulated by embedded Supercells ).

Therefore, it may depart from what 1000-500 MB thickness and 850-300 MB MEAN cloud-layer pattern might predict and is best forecast by a Vector approach that takes into account cold pool forced low-level convergence with mean layer fields.

The Bottom Line…while the Mountain Empire is not currently within the slight or enhanced risk regions on Wednesday, it is too soon to know exactly how this will play out and it is likely that this risk graphic will change during the next couple of days as storms form and alter the atmospheric setting over time.

One or more thunderstorm clusters, with potential for a severe weather outbreak, is expected from Tuesday into Wednesday.  Localized strong-severe storms may also develop to impact more limited corridors along their paths.  Please stay tuned to NOAA Weather Radio and your favorite media sources for possible watches and/or warnings that may be needed from Tuesday into Thursday ( June 21-23 ).

Mountain Area Forecast ( June 17-20 )

Remainder Of Friday Afternoon

Mostly cloudy with a chance of showers and patchy drizzle.  Seasonally cool with temperatures in the 60s to low 70s for locations along & north of the High Knob Massif-Tennessee Valley Divide ( warmer south toward the Tri-Cities ).

Friday Night Into Saturday Morning

Cloudy with a chance of scattered showers during the evening-early overnight.  Becoming partly cloudy into morning.  Winds shifting ENE-SE at 5-15 mph on middle-upper elevation mountain ridges and plateaus.  Temperatures in the 50s to around 60 degrees.

Saturday Afternoon

Any clouds giving way to mostly sunny, blue skies.  Pleasant conditions.  ESE-SSE winds 5 to 10 mph, with higher gusts.  Temperatures varying from upper 60s to lower 70s at the highest elevations into the upper 70s to lower 80s ( warmer toward the southwest and south of the High Knob Massif ).

Saturday Night Into Sunday Morning

Mostly clear.  Winds SE-SSE 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges.  Temperatures varying from mid-upper 40s to the mid-upper 50s ( coolest within mountain valleys with calm winds ).

Sunday Afternoon

Mostly sunny ( some high clouds possible ).  Light SE to S winds.  Temperatures varying from the low 70s at highest elevations to the lower-middle 80s.

Sunday Night Into Monday Morning

Mostly clear.  Winds becoming S-SW at 5-10 mph along mid to upper elevation mountain ridges.  Temperatures varying from the 40s in cooler mountain valley to the 50s to near 60 across exposed ridges-plateaus.

Weather Discussion ( June 16-20 )

Beautiful mammatus clouds, forming on the bottom side of a large cumulonimbus anvil, were captured over western Lee County by photographer Harold L. Jerrell Thursday.

Rainfall with storms, as often is the case at this time of year, was not uniform with large variations across southwestern Virginia from nothing up to 1.00″ to 2.00″ .

Locations from central-eastern Dickenson County into Buchanan County and portions of Russell, Tazewell, Washington, Smyth and Grayson counties endured the strongest thunderstorms with power outages still ongoing as of 4:58 PM on Friday ( June 17 ).

A mostly cloudy, cooler air mass has dominated Friday, especially along and north of the High Knob Massif-Tennessee Valley Divide.

Some light showers and drizzle have occurred along with low cloud bases that occasionally obscure the highest ridges.

Friday ( June 17 ) temperatures have been much cooler with afternoon readings only in the 60s to lower 70s in locations along and north of the High Knob Massif & Tennessee Valley Divide.

*The 4:45 PM temperature of 70.7 degrees in Clintwood being down from a PM MAX of 72.8 degrees.  Air temps have hovered around 60 degrees at the summit level of the High Knob Massif during the afternoon.

The hottest air being suppressed to the south and west, with a major heat dome forming during the weekend into next week across southwestern-central portions of the USA.

A pleasant Father’s Day weekend is on tap with beautiful skies ( low dewpoints ) and seasonally cool nights.

A renewed surge of heat-humidity in advance of another cold front will bring the chance for more strong-severe thunderstorms by the Tuesday-Wednesday period of next week ( June 21-22 ).  Stay tuned for updates.

Mountain Area Forecast ( June 13-16 )

Any Mid-Late Week Storm Could Be Strong & Produce Torrential Rainfall In Downpours.  A Slight Risk For Severe Thunderstorms Has Been Issued By The Storm Prediction Center For Thursday ( June 16 ).

The Mountain Empire will remain within a thermal-moisture gradient this week, with a large contrast in temperatures and dewpoints across the region.  This gradient will be fluctuating back and forth across the Cumberland Mountains.

Monday Night Into Tuesday Morning

Mostly clear.  Large vertical temperature spread between mountain ridges and much cooler valleys.  Light & variable winds below 2700 feet.  Winds SSW-WNW at generally less than 10 mph along mountain ridges above 2700 feet.  Temps varying from 40s in mountain valleys to the 50s to around 60 degrees along exposed middle elevation ridges-plateaus  ( extremes varying from 38 to 44 degrees in colder valleys of mid-upper elevations amid the High Knob Massif-Burkes Garden corridor to low-mid 60s at lower elevations in the Tennessee Valley southwest of the Tri-Cities ).

Tuesday Afternoon

Increasing mid-high clouds ( some cumulus possible ).  Becoming hazy & more humid late.  Hotter.  Slight chance of a hit-miss shower or storm by late afternoon.  Light and variable winds.  Temperatures varying from 70s in upper elevations to the middle 80s to around 90 degrees ( hotter south toward the Tri-Cities ).

Tuesday Night Into Wednesday  Morning

Hazy & humid.  Chance of showers and downpours in thunderstorms ( especially overnight toward morning ).  Light winds, except S-SW at 5-10 mph, with some higher gusts, along mountain ridges above 2700 feet.  Warm with temperatures mostly in the 60s to around 70 degrees.

Wednesday Afternoon

Humid & hazy with a chance for showers & downpours in thunderstorms.  Winds SSW-WSW at 5-10 mph, with some higher gusts ( stronger in storms ).  Temperatures varying from low-mid 70s to lower-mid 80s ( coolest in the upper elevations ).

Wednesday Night Into Thursday Morning

Chance of showers & downpours in thunderstorms.  Humid.  Winds SW to NNW at 5-15 mph, with higher gusts, on mid to upper elevation mountain ridges & plateaus.  Temperatures widespread in the 60s.

Thursday Afternoon & Evening

A chance of showers & downpours in thunderstorms.  Some storms could be strong to locally severe.  Winds W-NW 5-15 mph, with higher gusts, along mid-upper elevation ridges and plateaus.  Afternoon maxs varying from 70s at highest elevations to the 80s to around 90 degrees.

Weather Discussion ( June 12-16 )

Early Thursday Update

A hit-miss array of showers & downpours in thunderstorms impacted the mountain area during Wednesday ( June 15 ).

Conditions Wednesday marked a significant change from morning lows in the low-mid 40s in colder mountain valleys during the AM of June 14 as the region was again engulfed by steamy air on the moist side of a notable temperature-moisture gradient.

The Storm Prediction Center has the mountain area in a slight risk for severe thunderstorms today ( June 16 ).

The greatest risk today, with an Enhanced Region, is forecast to be centered upon either side of the West Virginia-Virginia border to the northeast of the Mountain Empire.

Stay tuned to NOAA Weather Radio for any possible watches and/or warnings that may be needed today.

Previous Discussion

A gorgeous Monday is being observed across the mountains with beautiful blue skies and low dewpoints.  Although the sun is a dynamo at this time of year, and feels hot in direct light on any day, air temperatures have been pleasant with readings varying from lower 70s to lower 80s.

Monday afternoon temperatures have peaked in the lower 70s ( at higher elevations in the High Knob Massif ) to the upper 70s to low 80s ( 83 degrees in Clintwood ).

Both temperatures and dewpoints are much higher to the south into the Tennessee Valley, from the Tri-Cities south and southwest.  This will generate a large temperature difference tonight into early hours of Tuesday.

*As of 6:30 PM the official NWS temperature in Clintwood had fallen from 83 degrees to 71 degrees ( to illustrate the cooling potential that will develop amid valleys as the sun continues to sink beneath the mountain horizon ).

The moisture gradient set up across the region Monday is very notable, with pleasant low dewpoint air north and northeast of the Tri-Cities and Tennessee Valley.

With clear skies, light winds, and low dewpoints the air temp will drop significantly tonight into Tuesday AM in mountain valleys within and northward to northeastward of the High Knob Massif ( MINS by Tuesday Morning could vary by more than 20 degrees along N-S and NE-SW tran-sects across far southwestern Virginia and NE Tennessee- southern Kentucky across this moisture gradient ).

This large moisture gradient will be gone by mid-week, with showers & downpours in thunderstorms increasing across the mountain landscape by Wednesday into Thursday.

Rainfall Amounts Since May 1

Some local showers and storms made it into portions of Dickenson & Buchanan counties during Sunday, with the bulk of rainfall activity focused over northern Kentucky into southern portions of West Virginia.

During the past 30+ days, since May 1, rainfall totals have varied significantly across the Mountain Empire with much more rain along and north of the High Knob Massif versus locations to the south.

Rainfall Totals May 1-June 13

Clintwood 1 W
8.29″

City of Norton WP
8.81″

Tri-Cities NWS
4.89″

*Totals in the High Knob Massif since May 1 have reached into the 10.00″ to 12.00″ range ( wettest locations being from portions of the Bark Camp Lake-Little Stony Creek basin into sections of the Big Stony Creek and South Fork of the Powell River basins ).

Much drier conditions to the south were reflected by the USA Drought Monitor last week ( even though local conditions are generally not well represented across complex terrain ).

The Black Mountain MesoNET station has recorded 8.18″ of rain since the beginning of May.  A recap of daily conditions:

Mountain Area Forecast ( June 10-12 )

Humidity, heat, and haze will be increasing into this weekend along with chances for at least hit-miss showers & thunderstorms  ( especially by late Saturday into Sunday ).  Slow down and take it easy as heat-humidity increases.

Thunderstorms could become strong to locally severe if clusters develop amid WNW-NW flow ( with potential for activity passing north of the Cumberlands initially to generate outflow boundaries that function as new trigger zones…stay tuned for later updates ).

Overnight Into Friday Morning

Partly cloudy ( high clouds ).  Light and variable winds.  Temperatures varying from low-mid 40s in cooler valleys to the 50s across mid-upper elevation ridges-plateaus.

Friday Afternoon

Partly to mostly sunny ( high clouds ).  Light WNW-N winds. Warmer with MAX temperatures varying from low-mid 70s in upper elevations to the low-mid 80s.  Some increase in humidity and haze.

Friday Night Into Saturday Morning

Partly cloudy ( some high clouds ).  Light S-WSW winds less than 10 mph along middle elevation ridges below 2700 feet. Winds SW to WNW at 5-10 mph, with some higher gusts, on mountain ridges above 2700 feet.  MIN temperatures from low-mid 50s in cooler mountain valleys to the low-mid 60s.

Saturday Afternoon

Partly cloudy.  Significant increases in humidity & haze.  Hotter.  Chance of a shower or thunderstorm.  Winds W at 5-10 mph.  MAX temperatures varying from mid-upper 70s in upper elevations to the mid to upper 80s ( hotter to the south toward the Tri-Cities ).

Saturday Night Into Sunday Morning

 Hazy, warm & humid.  Chance of a shower or thunderstorm ( especially in northern locations ).  WSW-WNW winds 5-15 mph, with higher gusts, along middle elevation mountain ridges and plateaus below 2700 feet.  Wind WNW-NW 10-20 mph, with higher gusts, along mountain ridges above 2700 feet.  Temperatures varying from 60-65 degrees in cooler valleys to around 70 degrees on exposed mountain ridges.

Sunday Afternoon

Partly to mostly cloudy.  Chance of showers & downpours in thunderstorms.  Some storms could be locally strong-severe with damaging winds.  Winds WNW-NW at 5-15 mph, with higher gusts.  Temperatures varying from lower 70s to the lower to middle 80s ( coolest at highest elevations ).

An increasingly stormy pattern into next week will need to be monitored for the potential of heavy to locally excessive rainfall amounts, as well as strong-severe thunderstorms.  Stay tuned for later updates in coming days at the pattern becomes more clear.

Weather Discussion ( June 9-12 )

A spectacular June air mass graced the mountain landscape during Wednesday into Thursday, with unseasonably cool temperatures that featured MINS in the 30s to lower 40s within mountain valleys by early hours of June 9.

Seasonally cool conditions continued to be featured through Thursday ( June 9 ) with PM MAXS varying from 60s at highest elevations in the High Knob Massif to the upper 70s to around 80 degrees at lower elevations.

A persistent WNW to NW flow pattern will be featured during coming days, with a huge heat ridge centered across central portions of the USA in the MEAN.

While a upper low could form and cut-off beneath the heat ridge, there will be a significant trough over or near New England to generate a baroclinic zone regardless of upper low formation.

This type of pattern will tend to keep the hottest air suppressed to the south and west of the Cumberlands as debris clouds ( blow off from upstream thunderstorms ) in this WNW-NW flow works together with terrain induced cloud formations to hold temperatures back a little more than would otherwise occur ( as is predicted by feedback from a wet May 1 to June 6 period ).

*It will still be hot, but not as intense or as prolonged in nature given May 1 to June 6 wetness.  This wet period will now become an important factor as evapotranspiration from trees and vegetation feeds into the overlying air in coming days to help increase clouds and chances for showers and thunderstorms ( by next week this could aid formation of an increasingly stormy, wet pattern ). 

Although details remain to be worked out, it appears that a persistent northeastern USA upper trough will enhance a temp gradient that aids thunderstorm development across the Great Lakes and Upper Midwest in coming days, with debris cloudiness ( initially ) advecting southeast across the Appalachians to partially filter insolation.  A local shower or thunderstorm could develop off the terrain Saturday.

Thunderstorm chances will increase along a front that forms in the temperature gradient by Saturday Night into Sunday, as haze, humidity levels increase significantly.

Next week a upper level low may form beneath the heat ridge ( or a WNW-NW flow will persist ) to enhance the risk for showers and downpours in thunderstorms.  Depending upon how this may play out, a heavy to excessive rainfall potential could arise and will need to be closely followed along with the chance for strong-severe storms.

Forecast models will jump around with heaviest rain amounts, but the signal for heavy to excessive rainfall totals is there on the GFS and European ( most importantly ) models and many ensembles.

Meanwhile, slow down and take it easy as the first surge of true summer heat & humidity develops into this weekend.

Mountain Area Forecast ( June 8-10 )

Tuesday Night Into Wednesday Morning

Partly to mostly cloudy.  Cooler.  WNW to NW winds decreasing to less than 10 mph along middle elevation ridges below 2700 feet.  WNW-NW winds 5-15 mph, with higher gusts, along upper elevation mountain ridges.  Temperatures varying from middle to upper 40s to the middle-upper 50s.

Wednesday Afternoon

Partly-mostly sunny.  Blue skies.  Unseasonably cool for the season with NW-NNW winds at 5-10 mph ( higher gusts on mid-upper elevation ridges ).  Temperatures varying from 50s at highest elevations to the middle 60s to lower 70s.

Wednesday Night Into Thursday Morning

Mostly clear and unseasonably cold.  Light winds along middle elevation ridges-plateaus.  NNW-N winds 5-10 mph on upper elevation mountain ridges.  Temperatures varying from upper 30s to lower 40s in coldest valleys of mid-upper elevations to the middle 40s to lower 50s.  Areas of fog possible, especially along major river valleys & lakes.

Thursday Afternoon

Mostly sunny.  Light W-NW winds.  Temperatures varying from 60s across upper elevations to the 70s in middle to lower elevations ( warmer south toward the Tri-Cities ).

Thursday Night Into Friday Morning

Becoming partly to mostly cloudy.  W to NW winds 5-15 mph along mid-upper elevation mountain ridges.  Temperatures varying in the 40s and 50s ( coolest in mountain valleys ).

Weather Discussion ( June 7-10 )

A refreshing air mass overspread the mountain area during Tuesday ( June 7 ), with much lower dewpoints ( humidity ) and beautiful blue skies.  An early summer treat!

Afternoon MAXS varied from 60s in upper elevations to the lower-middle 70s within middle elevations ( between 2000-3000 feet ) to the upper 70s to around 80 degrees in lower elevations.

Remember I break my forecast’s down by elevation zones:

Lower Elevations
Below 2000 Feet

Middle Elevations
2000-3000 Feet

Upper Elevations
Above 3000 Feet

*With respect to boundary layer conditions I often divide middle and upper elevations at the 2700 foot level.  This allows for the upward bulge generated amid the atmosphere by the High Knob Massif where many valley floors rest at or above 2700 feet.

The boundary layer refers to that portion of the lower atmosphere which is in contact with the Earth’s surface.  It is often defined as the friction layer, or that part which is most influenced by terrain generated drag.

The boundary layer tends to expand during the day with thermal heating and contract by night with cooling.  In complex terrain, such as that within the High Knob Massif area, multiple inversion layers develop at different levels on any given night if decoupling ( detachment ) occurs ( i.e., winds decrease and become detached in valleys from more organized winds amid the boundary layer, or blowing along its top, and are replaced by cold air drainage flows and associated circulations ).

The official NWS MAX in Clintwood reached 79 degrees on June 7, with a temperature drop to 56 degrees observed by Midnight.

While there will be plenty of dew forming on roses and other flowers in coming nights, it will come very close to turning frosty amid coldest valleys of middle to upper elevation within the High Knob Massif-Burkes Garden corridor into morning hours of Thursday ( June 9 ).

Mean dewpoints in the 30s within the 900 to 850 MB zone will be able to generate significant cold air drainage, amid light winds and mostly clear skies, with valleys above 2000 to 3000 feet becoming coldest during Wednesday Night into Thursday AM.

The current autumn-winter like upper air pattern will change radically into this weekend and next week, at least for much of the nation outside of New England where a chilly pattern looks to hold on beneath upper troughing.

A pattern like this in June typically signals a battle zone with showers & thunderstorms moving around the peri-phery of hottest air.  Exactly where this sets up into the weekend and next week will dictate how wet ( or not ) it becomes within the Mountain Empire.

Meanwhile, be sure to enjoy a few gorgeous days of awesome June conditions in the southern Appalachians!

Mountain Area Forecast ( June 6-8 )

ALERT For Areas Of Dense Fog Through Monday AM

Overnight Into Monday Morning

Chance of hit-miss showers.  Areas of dense fog.  Light winds below 2700 feet.  W-WNW winds 5-10 mph, with higher gusts, along mountain ridges above 2700 feet.  Temps in the 50s to around 60 degrees.

Monday Afternoon

Partly cloudy.  Continued warm and relatively humid.  Chance of a hit-miss shower or thunderstorm.  Light WSW to WNW winds generally less than 10 mph.  Temperatures varying from lower 70s at highest elevations to the lower to middle 80s.

Monday Night Into Tuesday Morning

Chance of an evening showers or thunderstorm.  Then partly-mostly clear.  Areas of dense fog.  Winds SW to W at 5-10 mph along mountain ridges-plateaus below 2700 feet.  Winds W-NW 5-15 mph, with higher gusts, along mountain ridges above 2700 feet.  Temperatures in the 50s to low 60s.

Tuesday Afternoon

Partly cloudy.  Becoming much less humid.  Winds W to NW at 5-15 mph, with higher gusts.  Temperatures varying from 60s at highest elevations to mid 70s to around 80 degrees.

Tuesday Night Into Wednesday Morning

Partly cloudy.  Cooler.  WNW-NW winds 5-15 mph, with higher gusts along upper elevation ridges.  Temperatures varying from upper 40s to the mid-upper 50s.

Mountain valley temperatures could dip into the upper 30s to middle 40s during Wednesday Night into Thursday Morning, coldest within mid-upper elevation valleys.

A wave of summer heat will begin building across the Tennessee Valley into the southern Appalachians by this weekend into early next week.  This may trigger thunderstorm development of the air mass variety initially, then the potential for clusters of storms by next week could bring a heavy-excessive rainfall potential.  Please stay tuned for updates on a changing June weather pattern.

Weather Discussion ( June 4-8 )

An array of showers and downpours in thunderstorms were observed during the weekend.

As the pressure gradient began increasing orographic clouds formed along the High Knob Massif, with both wave and pilatus cap clouds becoming visible during late Saturday ( June 4 ).  This set the stage for heavy rain into the overnight and Sunday.

Some amazing and strikingly beautiful cloud formations were observed during Sunday afternoon-early evening.

A general 1.00″ to 2.00″+ of rainfall into Sunday boosted June rain tallies into the 3.00″ to 5.00″+ category across much of the High Knob Massif area, with roaring water observed on steep creeks draining the massif.

While a hit-miss shower or thunderstorm will remain possible through Monday, a much drier air mass and refreshing change will be felt during Tuesday and Wednesday when seasonally cool temperatures will overspread the mountain region.

Temperatures in cooler mountain valleys will drop into the 40s during mid-week, with even some upper 30s to lower 40s being possible in colder valleys of mid-upper elevations.

The focus by the end of this week into this upcoming weekend will shift to building heat.  The first true heat of the Summer 2016 season.  Given May-early June wetness, the potential for thunderstorm formation will have to be respected, with cloud formation and such activity dictating how hot temperatures will get in many places ( the trend favoring heat that breaks by storms and the potential of a heavy to potentially excessive rainfall setting next week ).

Mountain Area Forecast ( June 2-5 )

 ALERT For Locally Heavy Rain With Downpours In Showers & Thunderstorms From Thursday Into This Weekend ( Hit-Miss Coverage At Any Given Time ).  Some Storms May Be Strong To Locally Severe.

The Storm Prediction Center Has Issued A Slight Risk Of Severe Thunderstorms For The Area Between 8 AM Saturday and 8 AM Sunday

The threat for downpours in showers & thunderstorms will continue into Sunday ( and become likely Saturday Night Into Sunday ).  Remain alert for changing conditions during outdoor activities this weekend.

Overnight Into Thursday Morning

Chance of showers & thunderstorms.  Mostly cloudy.  Areas of dense fog.  Light and variable winds on mountain ridges and plateaus below 2700 feet.  Winds SSW-WSW 5-10 mph, with higher gusts, on mountain ridges above 2700 feet.  Warm & humid with temperatures mostly in the 60s.

Thursday Afternoon

Hit-miss showers & thunderstorms.  Locally heavy rainfall.  Winds SSW to WSW at generally less than 10 mph outside of storms.  Temperatures varying from upper 60s to low 70s in upper elevations to the mid 70s to around 80 degrees.

Thursday Night Into Friday Morning

A chance of showers & thunderstorms.  Locally heavy rainfall possible.  Areas of dense fog.  Winds SSW-WNW at generally less than 10 mph outside of storms.  Warm and humid with temperatures widespread in the upper 50s to lower-middle 60s.

Friday Afternoon

Hit-miss showers & thunderstorms.  Locally heavy rainfall.  Winds SSW to WSW at generally less than 10 mph outside of storms.  Temperatures varying from upper 60s to low 70s in upper elevations to the mid 70s to lower 80 degrees.

Friday Night Into Saturday Morning

A chance of showers & thunderstorms.  Locally heavy rainfall possible.  Areas of dense fog.  Light & variable winds along mountain ridges-plateaus below 2700 feet.  Warm & humid with temps in the upper 50s to lower-middle 60s.

*Some storms could become strong to locally severe during the Saturday afternoon into Sunday period.  Low-level flow will increase during Saturday Night into Sunday AM to also increase orographic forcing into favored zones such as that of the High Knob Massif-Black Mountain corridor.

Saturday Afternoon

Hit-miss showers & thunderstorms.  Locally heavy rainfall.  Winds SSW to SW at 5-15 mph, with higher gusts, along mid to upper elevation mountain ridges and plateaus.  Humid.  Temperatures varying from low-mid 70s at the highest elevations to the lower-middle 80s.

Saturday Night Into Sunday Morning

Showers & downpours in thunderstorms becoming likely.  Locally heavy rainfall.  Winds SSW to SW 5-15 mph, with higher gusts, along mountain ridges-plateaus below 2700 feet.  Winds SW-WSW 10-20 mph, with higher gusts, along mountain ridges above 2700 feet.  Temperatures from the upper 50s to mid-upper 60s.

Sunday Morning Into Sunday Afternoon

Showers & downpours in thunderstorms.  Locally heavy rainfall.  Winds SSW-WSW at 5-15 mph, with higher gusts.  Temperatures varying from the 60s to lower-middle 70s.

Weather Discussion ( May 31-June 4 )

Early Saturday Update

While hit-miss showers and downpours in thunderstorms will be possible Saturday, they will become likely during Saturday Night & Sunday as a cold front pushes east into the Appalachians.  Some storms could be strong to severe from Saturday afternoon into Sunday.

Reference Early Summer 2016 In The Appalachians for more photographs of dramatic skies above the High Knob Massif as thunderstorms began erupting Thursday afternoon ( June 2 ).

The High Knob Massif, especially central-eastern portions, have been a focus for heavy rainfall during the past few days.

Locations in the RED on the above graphic had an estimated 2.00″ to 3.00″+ of rainfall during the 36-hour period ending at just after midnight on June 3 ( 12:08 AM ).  The heaviest rains being focused upon the Little Stony Creek Basin ( from above Bark Camp Lake to along Little Stony Gorge ) and eastern sections of the Big Stony Creek Basin ( in the Glades ).

Strong water level rises, with ROARING whitewater, were observed on both Little Stony Creek and Big Stony Creek.

Forecast models continue to show an increasing coverage of showers-thunderstorms by later Saturday & Saturday Night into Sunday.

The GFS ( above ) keeps more of a hit-miss pattern while the NAM and European models forecast widespread coverage to develop into Saturday Night and Sunday.  The European is placing the heaviest rainfall corridor across far southwest Virginia and extreme southeastern Kentucky, as well as along portions of the lower Tennessee Valley and plateau.

The Storm Prediction Center has the entire area within a slight risk for severe thunderstorms between 8:00 AM Saturday and 8:00 AM Sunday.

Wind damage will be the greatest severe risk parameter, outside of always dangerous lightning and downpours of heavy rainfall.

An added factor will be increasing pressure gradient winds and enhancement of orographic forcing by Saturday Night into Sunday in advance of a upper air trough and surface cold frontal boundary.  This will favor a heavy to excessive rainfall potential for the High Knob Massif-Black Mountain corridor on general SW air flow trajectories.

Please remain alert to changing conditions this weekend and keep NOAA Weather Radio and mobile devices handy when outside to monitor the potential for strong to locally severe storms and heavy rains.

Previous Discussion

A summery air mass will remain in place across the Mountain Empire into this weekend with a array of  showers and downpours in thunderstorms.

The pattern observed during May 31-June 1 will be repeated, with an increasing coverage, into this weekend.  Downpours of 0.50″ to 1.00″+ have been observed and can easily occur in the stronger or more persistent activity on any given day.

Between 1.00″ and 2.00″ of rain fell from Bark Camp Lake across much of the Little Stony Creek Basin into the Guest River Gorge area during June 1 as persistent, back-building storms developed over eastern portions of the High Knob Massif ( below ).  Additional heavy action form along portions of Black & Pine mountains to the NW-N of Norton & SW of Pound.

While heating generally offers the best development, showers & downpours will not be restricted to just the daylight hours amid such a warm and buoyant air mass.

A tropical air mass following a wet May has turned the mountain landscape into a temperate rain forest, with many creatures great and small actively pursuing their life strategies.

Forecast models continue to show the heavy rainfall potential, but struggle with placement of amounts.

The highest resolution version of the NAM looks like it has a bad rash, or case of the measles, as it attempts to forecast where the heaviest rainfall will fall.

All models, including the European, are on board with the heavy to locally excessive rainfall potential through this upcoming weekend.

With luck, a drier and nice air mass will arrive for at least a while next week.

Stay tuned to NOAA Weather Radio for any possible watches and/or local warnings that may be needed through coming days.