ALERT For Accumulating Snow Mainly At Mid-Upper Elevations Through Early Monday Morning – Locally At Elevations As Low As 1500 Feet Along & North Of The High Knob Massif
Heavy Snow On Eagle Knob of High Knob Massif
Update At 5:30 AM Monday – Snow is falling heavy enough to begin sticking with temps above freezing in Clintwood, with roadways now covered at upper elevations within the High Knob Massif where temperatures are in the 20s.
Some slick travel will be possible on higher elevation roads, especially those that cross through terrain above 3000 feet, but due to the snowfall rates some brief slushy travel will also be likely at elevations below 3000 feet.
University Of Virginia’s College At Wise – Accumulating Snow
A upper air disturbance will be crossing the mountains into Monday with another round of snow. Most significant amounts are expected at elevations above 3000 feet, with lesser totals in middle elevations between 2000-3000 feet. Limited sticking is expected below 2000 feet. Due to the timing of heaviest snow, snowfall rates could be highest around-before AM commutes.
Snowfall Forecast – Monday AM ( April 9 )
1″ or less at elevations below 3000 feet
1″ to 2″ at elevations above 3000-3500 feet
Locally higher amounts are possible at highest elevations where air temperatures have been coldest ( generally near or below freezing during the weekend ).
Sunday Night Into Monday Morning
Lowering and thickening clouds with a rain-snow mix and snow developing during the predawn-morning. A period of moderate to heavy snow will be possible, especially at mid to upper elevations. Light NE surface winds to breezy SW winds highest elevations. Temps varying from the 20s to low-mid 30s.
Monday Morning Through The Afternoon
Morning snow giving way to a chance of light rain showers. SW winds shifting NW by late at generally 10 mph or less. Temps varying from 30s in upper elevations to the mid-upper 40s ( milder to the south into the Great Valley ). Orographic clouds ( dense fog ) at highest elevations.
Monday Night Through Tuesday Morning
Mostly cloudy. Chance of flurries, especially at upper elevations in the High Knob Massif, then becoming partly cloudy into morning. NW-N winds 5-10 mph with some higher gusts. Temperatures in the 20s to low-mid 30s, coldest at upper elevations. Wind chills in the 20s to low 30s, except 10s at highest elevations.
Tuesday Afternoon
Partly cloudy. Seasonably chilly. NW winds 5-10 mph. Temperatures varying from upper 30s to low 40s in upper elevations to the upper 40s to low-mid 50s ( milder south into the Great Valley ).
Tuesday Night Into Wednesday Morning
Mostly cloudy, then becoming partly to mostly clear by morning. Light WNW-NW winds. Temperatures varying from low-mid 20s in mountain valleys to the low-mid 30s, locally colder within high valleys of the High Knob Massif.
A warmer and more active spring rain-thunderstorm pattern is being monitored for late this coming week into RACE Weekend at Bristol. Stay tuned for later updates.
Weather Discussion ( Winter Lingers )
Monday Evening Update
A wintry morning in April greeted your Monday as snow fell briskly from the predawn through the post-sunrise period.
Eagle Knob of High Knob Massif at 7:09 AM – April 9, 2018 ( Moderate-Heavy Snow )
The greatest snow amounts occurred in upper elevations of the high country, with up to 0.28″ of water equivalent reported at both Big Cherry Lake Dam and on Eagle Knob ( 2-3″ of snow ).
To the east, Joe Fields measured 1″ of snow on the ground in the High Chaparral community at 8:30 AM. Amounts were generally less than 1″ at elevations below 3000 feet ( 0.5″ depth Clintwood ) with 0.6″ ( 0.06″ water equivalent ) reported by Wayne & Genevie Riner on Long Ridge of Sandy Ridge up to observation time.
Long Ridge In Dickenson County At 8:52 AM – April 9, 2018
I think humans and ALL Creatures Great & Small will certainly welcome true Spring when it finally arrives to stay this year, as the Ole Man Of Winter is beginning to ”wear out his welcome.”
University Of Virginia’s College At Wise
Snow melted away relatively fast in Wise but lingered throughout the day, beneath some nice mountain waves, along northern slopes at upper elevations.
*This latest event brings the days with 1″ or more of snow depth to 11 weeks for the 2017-18 winter season on northern slopes at the upper elevations in the High Knob Massif ( High Knob Lake Basin ).
While a few snow flurries are falling on High Knob tonight, the main focus through Wednesday will just be cold temps with mountain valleys experiencing another hard freeze during Tuesday Night into Wednesday AM.
Previous Discussion
Winter conditions will linger for a few more days before a major pattern change introduces a warmer spring-storm regime by late in the upcoming week-next weekend.
High Knob Massif Webcam – University Of Virginia’s College At Wise
An unseasonably cold Sunday morning for April greeted the mountain landscape with temperatures varying from 10s at upper elevations to the 20s ( 22 degrees in Clintwood ).
High Knob Massif Webcam – University Of Virginia’s College At Wise
Sunday remained so cold that extensive rime covering the high country of the High Knob Massif was actually able to linger throughout the daylight hours at highest elevations ( with snow on northern slopes ).
Quite a feat, indeed, for early April given that the Noon Solar Angle over the High Knob peak is now 61.1 degrees.
A solar angle of 61.1 degrees above the horizon at noon means that insolation ( incoming solar radiation ) is being spread across 1.14 units of surface area to generate a solar intensity of 87.5 percent of what it would be if the sun were directly overhead ( * ).
*The sun is NEVER directly overhead outside the tropics ( 23.5 degrees N to 23.5 degrees S ) and reaches a maximum over the High Knob peak during the Summer Solstice when the noon solar angle is 77.0 degrees ( June 21 ).
At that time insolation is spread across 1.026 units of surface area to generate a solar intensity of 97.4% of what if would be if the sun were directly overhead. Although MAX solar intensity occurs in June, due to seasonal lag-time forced by the slower accumulation of heat by surfaces the MAX in mean annual temperature typically does not occur until July. Interestingly, in the High Knob Massif, highest annual temps sometimes occur during Spring, prior to full leaf maturation, as clouds become so abundant during Summer that insolation is increasingly blocked.
European Model 850 MB Temp Analysis At 8 AM Sunday – April 8, 2018
The Sunday morning 850 MB temperature analysis from the European Model certainly showed this unseasonable April cold, and the anomalies ( below ) associated with it.
European Model 850 MB Temp Anomalies At 8 AM Sunday – April 8, 2018
Looking ahead this eastern USA trough will be replaced, at least for a short time, by ridging forming in advance of an upper wave that is looking increasingly potent on forecast charts by late this coming week into the weekend.
European Model 51-Member Ensemble Mean 500 MB Anomalies: Days 4-8
The focus in coming days will be on this wave and whether or not it does intensify to develop a negative tilt or if the wave maintains a positive tilt ( the former = a much more potent system ). Significant rain and thunderstorms could result amid an increasingly large temperature gradient if the wave undergoes significant amplification ( since cold air will remain abundant to the north across Canada ).
More cold air, and perhaps even more snow, will be possible if this upcoming wave amplifies significantly by around the April 15-16 period ( way out in time and merely speculation at this point, so check back for updates ).
