**UPDATE…ALERT For Dense Fog Continues Into Wednesday Night For Middle & Upper Elevations Along-North Of The High Knob Massif-Tennessee Valley Divide
ALERT For Dense Fog At Mid-Upper Elevations Along And North Of The High Knob Massif-Tennessee Valley Divide From Late Tuesday Afternoon Into Wednesday
*A prolonged period of dense fog ( low clouds ) will develop as colder air invades the front range of the mountains from late Tuesday into Wednesday on upsloping northerly winds. A cold, damp & raw feeling day is expected Wednesday when air temps will struggle in the 30s to lower 40s in locations along and north of the High Knob Massif & Tennessee Valley Divide, with milder conditions leeward of the mountains into river valleys of the Clinch, Holston and Great Valley.
Overnight Into Wednesday Morning
Colder. Rain developing during the predawn-morning. Dense fog at mid-upper elevations along and north of the High Knob Massif and Tennessee Valley Divide. NNW-NNE winds at 5-10 mph, with some higher gusts. Temps falling into the 30s to around 40 degrees. Wind chills dropping into the 20s to lower 30s at the highest elevations.
*The potential for some local freezing rain will exist along northern slopes-crest lines of the High Knob Massif with cooling on northerly upslope flow into the lower 30s.
Wednesday Morning Into The Afternoon
Rain tapering to showers-drizzle. Nasty & bone chilling. Low cloud bases with dense fog at mid-upper elevations along-north of the High Knob Massif & Tennessee Valley Divide. Winds N-NE at 5-10 mph. Temperatures varying from lower 30s to lower 40s. Some breaks in the overcast possible leeward of the High Knob Massif-Black Mountain by mid-late afternoon. Wind chills in the 20s to around 30 degrees at upper elevations.
Wednesday Night Into Thursday Morning
Low clouds ( widespread dense fog continuing at mid-upper elevations ). Chilly. A chance of light showers and drizzle. Light N-NE winds becoming variable in direction at upper elevations. Temperatures near steady or slowly rising in the 30s to lower 40s.
Thursday Morning Into The Afternoon
Becoming partly to mostly sunny. Winds WNW-NW at 5-10 mph, with some higher gusts. Temperatures varying from the lower 40s to the lower 50s.
Thursday Night Into Friday Morning
Partly to mostly clear ( a period of increased low clouds possible into the morning ). Winds NW-N at 5-15 mph, with some higher gusts, on mid-upper elevation mountain ridges and exposed plateaus. Temperatures varying from the low the middle 20s to the middle 30s. Wind chills in the 10s in upper elevations ( near 10 degrees highest peaks in gusts ).
Partly to mostly sunny. Cold. N-NE winds 5-10 mph, with some higher gusts. Temperatures varying from the 20s in upper elevations to the middle 30s to around 40 degrees. Milder south into the Great Valley.
Friday Night Into Saturday Morning
Mostly clear ( some high clouds possible ) and unseasonably cold. Light and variable winds on mountain ridges. Temps varying from the upper 10s to mid-upper 20s, except as cold as 10-15 degrees in colder upper elevations valleys.
Weather Discussion ( Nasty & Cold )
Wednesday Afternoon Update
Dense fog has now covered hundreds of square miles for 24 consecutive hours across northern Scott County, southern-central Wise County & central-southern Dickenson County.
The National Weather Service’s recognition of this:
I typically never say anything on this site, but as you see and experience this, drive in this, and know how widespread it is for 24-hours then ask this question:
If this occurred in the Great Valley, from Morristown to the Tri-Cities, what would be the resulting action?
Likely – Official Recognition with a Dense Fog Advisory.
It is not just MRX, but also RLX; however, MRX has the largest population impacted by these events, even though every single person COUNTS and a small community is just AS IMPORTANT as a big city which is my bottom line.
A raw, damp chill has, of course, been the other big story. Check out today’s temperature trend from Nora 4 SSE on Long Ridge of Sandy Ridge, where dense fog has also been persistent all day long.
Temperatures at upper elevations in the High Knob Massif have been mainly in the mid-30s all day ( 33 to 38 degrees ).
Fog will continue through this evening, and it is looking more likely that it will continue into Thursday before the cloud bases finally lift.
Please slow down and be extremely careful as it has been difficult to see vehicles on the road, not to even mention other things like people or deer!
Widespread low clouds ( dense fog ) are about as thick as they get across mid-upper elevations along and north of the High Knob Massif & Tennessee Valley Divide as colder air is being lifted vertically over a moist mountain landscape.
I had this well forecast in advance, reference my 110617 Forecast for previous details on this nasty period of weather conditions.
Conditions will become colder and even more nasty as a round of rain develops overnight into Wednesday morning.
Temperatures along northern slopes and crest lines in the high country will be borderline, or very close to freezing, as rain redevelops overnight into Wednesday morning. Close enough that folks traveling along State Route 619, 160, and Routes 238, 237, as well as others above 3300 feet, should be alert for possible slick patches amid the pea-soup fog.
If low clouds ( fog ) hang tough in the upslope flow through the day Wednesday then temperatures in Norton-Wise will hover in the nasty 30s to around 40 degrees, with somewhat milder conditions at lower elevations and within locations downslope and leeward of the High Knob high country and Tennessee Valley Divide.
A low cloud deck and neutral to slight warm air advection may help hold temperatures near steady Wednesday Night into Thursday morning in advance of the next push of even colder air set to arrive by Friday.
If the warm advection can out-weigh the neutrality, then rises in cloud base levels may also occur during the period of Wednesday Night-Thursday AM with eventual break-up of the cloud deck expected during the day Thursday.
The mountain area will be on the fringe of a big blob of much below average temperatures ( seen above ) over the western portion of Canada by Friday, with the core of the very coldest air extending from northern West Virginia northeastward into the New England states.
This will set the stage for the coldest temperatures of this season, to date, heading into Friday Night & Saturday AM, with 10s and 20s widespread. Favored frost pockets will have the chance, at least, to plunge toward 10 degrees if skies are clear and winds decouple ( even colder readings will be possible, especially where 850 MB temps are colder toward the eastern-northern highlands in West Virginia; however, low clouds from Great Lake moisture could be a hindrance there, along with gustier 850 MB winds ).
Please use extreme caution in this very dense fog.