Increasing low clouds will prevent frost in most places along and north of the High Knob Massif and Tennessee Valley Divide into the overnight-morning hours of Tuesday. Patchy frost will be possible lee of the mountains with less cloudiness, and locally amid valleys should current clouds dissipate before sunrise.
A chance for mountain valley frost will become more significant during Tuesday night into Wednesday morning with mostly clear skies across the entire area ( ridges will be milder with increasing air flow developing into Wednesday morning ).
Overnight Into Tuesday Morning
Increasing low clouds, especially along and north of the High Knob Massif-Tennessee Valley Divide. Chance of a lower elevation sprinkle or upper elevation snow flurry. NNW-N winds 5-15 mph, with higher gusts, along upper elevation mountain ridges. Temps dropping into 30s to around 40 degrees ( around 30 degrees at the summit of High Knob Massif ). Wind chills in the upper 10s and 20s along highest mountain ridges.
Mid-Morning Tuesday Through The Afternoon
Decreasing clouds. Beautiful blue skies into the afternoon. Seasonably cool. NNW to NNE winds 5-10 mph, with higher gusts. Temperatures varying from the 40s upper elevations to the 50s to lower 60s ( 54-59 degrees in Norton-Wise ).
Tonight Into Wednesday Morning
Mostly clear ( some high clouds possible ). Large vertical temperature spread developing between colder valleys and milder mountain ridges. SSE to SSW winds increasing into the overnight to 10-20 mph, with higher gusts, on exposed mid-upper elevation mountain ridges. Temps varying from frosty 20s to lower 30s in colder valleys ( with calm winds ) to the 40s on milder, exposed mountain ridges.
**An ALERT For Strong Winds Will Be Likely For The Period From Wednesday Night Through Thursday. SSE-SW winds of 20-40+ mph will become possible during this time.
Weather Discussion ( March 28-29 )
Air turned much cooler behind an overnight cold front that produced brief downpours of rain, with lightning-thunder, across much of Wise, Dickenson, and Buchanan counties during the predawn hours of Monday.
Temperatures became coolest into the mid-morning to mid-day period of Monday, with low-mid 40s in Norton-Wise and Sandy Ridge and 30s amid upper elevations of the High Knob Massif.
*At the same time as temps were in the low-mid 30s in the High Knob Massif, air temperatures were in the 50s within the Great Valley of northeastern Tennessee ( Tri-Cities southwest ) on Monday.
Andrew Greear, Superintendent of the Norton Water Plant, reported 0.28″ of rainfall into early Monday ( measured by Joe Carter ). A total of 0.15″ officially fell in Clintwood.
This brought the March 2016 total to 1.62″ in the City of Norton, with 12.76″ during the year to date ( January 1 to March 28 ).
Gary Hampton, Superintendent of the Big Stone Gap Water Plant, reported 0.63″ of rainfall at Big Cherry Dam during the March 24-28 period.
This brought the March 2016 total to 2.18″ at Big Cherry Lake Dam, with 17.64″ during the year to date ( January 1 to March 28 ).
The cloud deck began to break up and dissipate by early afternoon, which allowed temperatures to rise into lower 40s atop the lofty High Knob Massif and the upper 40s to lower 50s in Norton-Wise.
Following a gorgeous sunset with nearly cloud free skies, a redevelopment of low clouds occurred on northerly upslope flow in locations along and north of the High Knob Massif during evening hours of Monday.
This redevelopment of clouds on upslope flow will help prevent frost in most locations into the overnight, along- north of the High Knob Massif-Tennessee Valley Divide.
*There is not yet much vegetation that can be harmed in this area by sub-freezing temperatures, except for anything someone might have planted outdoors that is not native to this area.
Following a seasonally chilly Tuesday the focus tonight will be on a much better chance for mountain valley frost, with a continuation of mostly clear-clear skies. Exposed mid to upper elevation mountain ridges-plateaus will tend to be frost free as mixing increases overnight into Wednesday.
The next important weather system will allow March to end more Lion-like as rain and thunderstorms develop Thursday into Thursday Night. This system will have the potential to generate some heavy rainfall amounts, with strong winds developing across the mountains by Wednesday Night into Thursday ( when an ALERT may be needed ).