*Above average temperatures will tend to dominate much of this work week within a hazy, maritime tropical ( mT ) air mass. Showers & thunderstorms, with hit-miss downpours, will be possible ( especially mid-morning to early evening ).
Due to weak winds aloft any shower or thunderstorm will be slow moving and capable of dropping heavy rainfall over local areas.
*The coverage of showers & thunderstorms will increase later this weekend into the Labor Day Holiday period, with downpours. Temperatures will tend to slightly decline due to an increase in cloudiness and showers-thunderstorms.
*An above average temperature trend is currently expected to continue through the first week of September.
Overnight Into Monday Morning
Partly cloudy to mostly clear. Areas of fog. Light S-SW winds generally less than 10 mph on mid-upper elevation mountain ridges. Temperatures varying from mid-upper 50s in valleys at upper elevations to the low-middle 60s.
Monday Morning Through The Afternoon
Partly cloudy. Chance of hit-miss showers-thunderstorms. A local downpour possible. Light & variable winds. Temps varying from low-mid 70s to the low-mid 80s ( coolest at upper elevations above 3000 feet ).
Monday Night Into Tuesday Morning
Partly to mostly clear. Small chance of a shower or storm. Light and variable winds becoming SSW-WSW at 5-10 mph, with higher gusts, mid-upper elevation mountain ridges. Areas of fog. Temperatures varying from upper 50s to lower 60s in cooler valleys to middle-upper 60s.
Tuesday Morning Through The Afternoon
Partly cloudy. Chance of hit-miss showers-thunderstorms. Local downpours possible. Winds S-SW generally less than 10 mph outside any storms. Temperatures varying from the lower-middle 70s to the lower-middle 80s.
Tuesday Night Into Wednesday Morning
Partly to mostly clear. Small chance of a shower or storm. Light and variable winds becoming S-SW at 5-10 mph, with higher gusts, mid-upper elevation mountain ridges. Areas of fog. Temperatures varying from mid-upper 50s to lower 60s in cooler valleys to the middle-upper 60s.
Wednesday Morning Through The Afternoon
Partly cloudy. A chance of hit-miss, slow moving showers and thunderstorms. Downpours likely in any activity. Light SSW-SW winds generally less than 10 mph. Temperatures varying from low 70s to the lower 80s ( warmer south into river valleys of the Clinch, Powell, and Holston ).
Wednesday Night Into Thursday Morning
Variable clouds. Chance of a shower or thunderstorms. Downpours possible. Areas of fog. Winds SW-W at 5-10 mph, with some higher gusts, on mid-upper elevation mountain ridges. Temperatures mainly in the 60s.
Weather Discussion ( More Summer )
A late summer weather pattern will return to dominate conditions through the Labor Day Holiday. This comes in wake of pleasant conditions in recent days.
High Knob Massif Webcam – University Of Virginia’s College At Wise
Minimum temperatures fell into the 40s in cooler mountain valleys at upper elevations during August 23-25 ( low-mid 40s in coldest locations ).
High Knob Massif Mesonet *Big Cherry Lake Valley 2 June 1-August 25, 2018 Avg. Daily MAX: 70.9 degrees Avg. Daily MIN: 57.6 degrees Summer MEAN: 64.2 degrees Highest Temperature: 79 Lowest Temperature: 46
*MAX temperatures were somewhat higher and MIN temperature were somewhat lower within open portions of the Big Cherry Wetland Valley. Temps are all National Weather Service calibrated and very accurate.
High Knob Massif Webcam-University Of Virginia’s College At Wise
A notable increase in haze, with some orographic clouds, was observed developing Sunday as a continental Polar air mass gave way to advection of maritime tropical air.
European 51-Member Ensemble Mean 850 MB Temp Anomalies: Days 1-5
Above average temperatures during the next 5 days, on average, will be supported aloft by mean upper air ridging across the southern and eastern USA.
European 51-Member Mean 500 MB Height Anomalies: Days 1-5
This basic pattern is expected to continue through the next 10 days, which includes the Labor Day Holiday period.
European 51-Member Mean 500 MB Height Anomalies: Days 6-10
*Showers & downpours in thunderstorms will continue at times, amid a humid air mass, into Tuesday Night.
Heavy to locally excessive rain amounts will remain possible in advance of a strong autumn-like cold front expected to arrive by late Tuesday.
NOAA’s Storm Prediction Center has issued a marginal risk of severe thunderstorm development along and in advance of this cold front.
*Cloud bases will lower and the air will turn notably cooler on northerly winds through Wednesday, with lingering showers possible in advance of a secondary dewpoint boundary that ushers in an early autumn-like air mass late Wednesday into Thursday.
An early autumn-like air mass will drop temperatures into the 40s to middle 50s within locations along & north of the High Knob Massif-Tennessee Valley Divide by Thursday AM. Even cooler air may be felt in colder mountain valleys by Friday morning ( August 24 ). Stay tuned for updates.
*The cooler, drier break will be temporary with a return of humid air and a trend toward above average temperatures by next weekend into the final days of August 2018.
Overnight Into Monday Morning
Partly-mostly cloudy. Muggy. Areas of dense fog. A chance of showers & thunderstorms. Locally downpours possible. Light SSE-SSW winds. Temperatures in the 60s to low 70s.
Monday Morning Through The Afternoon
Muggy & warm with a chance of showers & downpours in thunderstorms. Locally heavy rain possible. Light S-SW winds. Temperatures varying from upper 60s-low 70s in upper elevations to the upper 70s to lower 80s ( warmer south into the Great Valley ).
Monday Night Into Tuesday Morning
Mostly cloudy. Becoming breezy to windy. Chance of showers & thunderstorms. Local downpours possible. Winds S-SSW at 5-15 mph, with higher gusts, on mountain ridges-plateaus below 2700 feet. Winds SW 10-20 mph, with higher gusts, on mountain ridges above 2700 feet. Muggy with temperatures in the 60s to lower 70s.
Tuesday Morning Through The Afternoon
Showers & thunderstorms becoming likely. A few storms could be strong to severe. Local downpours. SW winds 5-15 mph, with higher gusts. Temperatures varying from upper 60s to the upper 70s.
Tuesday Evening Into Wednesday Morning
Showers & thunderstorms likely into the evening, then a chance of showers. A few storms could be strong-severe early with downpours. SW winds shifting W-WNW at 5-15 mph, with higher gusts into morning. Temps falling into the upper 50s to middle 60s.
Wednesday Morning Through The Afternoon
Mostly cloudy with a chance of showers. Low cloud bases at upper elevations, with dense fog into mid-morning to early afternoon at high elevations. Winds NW at 5-15 mph with some higher gusts. Temperatures varying from lower 60s to the low-mid 70s ( warmer south into the Great Valley ).
Wednesday Night Into Thursday Morning
Partly-mostly cloudy early, then decreasing clouds with areas of fog. NW-NE winds diminishing to 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures dropping into the 40s to middle 50s.
Thursday Afternoon
Sunny. Very pleasant. Blue skies. Light N-NE winds. Temperatures varying from lower-middle 60s in upper elevations to the lower 70s.
Thursday Night Into Friday Morning
Clear and unseasonably cool with a large vertical temp spread developing between the colder valleys and milder mountain ridges-exposed plateaus. Winds becoming SE to SSE at 5-10 mph, with higher gusts, on mid-upper elevation mountain ridges. Temperatures varying from upper 30s to lower 40s in colder valleys at upper elevations to the mid 40s to low-mid 50s ( mildest on middle elevation ridges ). Areas of dense river valley fog.
Weather Discussion ( Changes )
With the 12th Annual High Knob Naturalist Rally now just over 1 month away, it is time for a nip to be felt amid air of the high country. Yeah, to less humid air!
September 29, 2018 at High Knob Lake Recreation Area
Featuring the most mountain-top lakes of any mountain in the southern-central Appalachians, this year’s 12th Annual Naturalist Rally will be held at 3500+ feet above mean sea level where the air is always cooler in the high country.
USDA Forest Service – High Knob Lake Recreation Area – Summer 2018
Meanwhile, the relentless stretch of muggy air continues for a little while longer until the first autumn-like cold front ushers in a temporary break by mid-late week.
High Knob Massif Webcam – University Of Virginia’s College At Wise
A refreshing and much cooler air mass will temporarily bring a dramatic change to the mountain area during the August 22-23 period into Friday AM of August 24.
European Model 850 MB Temp Forecast At 8 AM August 23, 2018
The middle range trend will be for humid air and above average temperatures to return during the final days of August 2018.
European 51-Member Ensemble Mean 500 MB Height Anomalies: Days 6-10
NOTE: The 5.24″ of rain measured in Clintwood during August 1-19 pushed the annual total to 46.03″ ( 14.45″ above the 1981 to 2010 average for this point in a year ). The January 1-August 19 total being near the long-term annual average for Clintwood.
NWS Precipitation Analysis – Percent of Normal – During Past 90-Days
*Although a general 47.00″ to 57.00″ of precipitation have fallen in the City of Norton-High Knob Massif area so far this year, the actual annual departure is generally only near to a little above average. This is due to hit-miss summer thunderstorms and local wet feedbacks, superimposed upon the larger-scale weather pattern, which have allowed certain sites and corridors ( e.g., northern Virginia into Pennsylvania ) to receive above to much above average summer rainfall across the eastern USA ( versus nearby locations with near average summer rains ).
ALERT For The Potential Of Localized Flash Flooding Into This Weekend With Slow Moving Thunderstorms
Torrential downpours in slow moving thunderstorms have dropped heavy rainfall amounts across Dickenson County & northern portions of Wise County as of 1:30 AM Saturday, with potential for additional development of this nocturnal activity. Folks living along streams and in low-lying, flood prone locations should remain alert through this weekend.
*A moist, humid air mass will remain in place through this weekend with the potential for heavy to excessive rain amounts within localized places.
*The heavy rainfall threat is being enhanced by weak winds aloft beneath another anomalous, for this time of year, upper-level low with slow moving activity.
*A cold front will slowly work south and attempt to cross the mountains later in this weekend-early next week. The threat for heavy-excessive rain amounts will continue until somewhat cooler, drier air is transported south behind this boundary.
The Storm Prediction Center has expanded a marginal risk of severe thunderstorm development southwest to now include all of the mountain area through Wednesday
Storm Prediction Center Risk Regions
*A humid air mass will rule the mountain landscape through the upcoming week with chances of hit or miss showers & thunderstorms during early week.
*Another upper air trough will be developing over the eastern USA with increasing chances of showers and thunderstorms by later this week into the upcoming weekend ( August 8-12 period ).
*Near to above average temperatures during early-mid week will tend to cool with increasing showers and thunderstorms by later in the week-weekend.
Overnight Into Monday Morning
Partly-mostly cloudy. Chance of a localized shower. Areas of valley fog. SW winds 5-10 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures in the 60s to near 70 degrees.
Monday Morning Through The Afternoon
Mostly cloudy. Chance of showers & thunderstorms. Local downpours. Winds S-SW generally less than 10 mph outside of hit or miss showers-storms. Temperatures varying from lower-mid 70s to the upper 70s to lower 80s ( warmer south into the Great Valley ).
Monday Night Into Tuesday Morning
Partly to mostly cloudy. Chance of a shower or storm, especially during the evening. Areas of fog. Winds SSW-W at 5-15 mph with some higher gusts on mid-upper elevation mountain ridges. Temperatures widespread in the 60s.
Tuesday Afternoon
Partly to mostly cloudy with a chance of hit-miss showers and thunderstorms. Local downpours. Winds SW-W at 5-10 mph. Temperatures varying from the low-mid 70s in upper elevations to the low-mid 80s.
Tuesday Night Into Wednesday Morning
Partly to mostly cloudy. Areas of fog. Chance of a localized shower-thunderstorm. Winds SSW-WSW at 5-15 mph, with higher gusts, on middle-upper elevation mountain ridges. Temperatures from lower 60s to the lower 70s.
Wednesday Afternoon
Mostly cloudy. Periods of showers & thunderstorms. Local downpours. Some storms could be strong to locally severe. Winds SW-WNW at 5-15 mph, with higher gusts. Temps in the 60s ( upper elevations ) to the low-middle 70s.
Summer 2018 has been a little warmer than Summer 2017 within the Big Cherry Lake Valley of the high country.
