Weather Headlines

ALERT For Dropping Cloud Bases And Dense Fog From Upper Elevations Into Middle Elevations On Northerly Upslope Flow And Cold Air During Saturday

*Dropping cloud bases on northerly upslope flow is expected to impact locations along and north to northwest of the High Knob Massif and Tennessee Valley Divide as air turns much colder through Saturday.

Saturday Update_2:00 PM: Low clouds are engulfing a wide area on upsloping northerly winds in wake of soaking rainfall. Afternoon air temperatures vary from 30s at upper elevations (gust wind chills in 20s) in the High Knob Massif to the middle 40s at lower elevations to the north.

Early afternoon temperatures are in the low-mid 50s toward the south in the Tennessee Valley, from TYS to TRI, with good visibility under downslope flow.

Caution for high stream levels through Saturday on headwater creeks draining the High Knob Massif-Black Mountain corridor in wake of significant rain.

Big Stony Creek crested 1.0 foot (12″) below flood stage this morning (21 March), in wake of soaking rainfall, to continue a trend of elevated stream levels throughout the month of March 2020.

Precipitation Totals
1-21 (AM) March 2020

Black Mountain Summit
7.01″

*Big Cherry Lake Dam
6.71″

Eagle Knob Summit
6.72″

*The 2008-2019 average for the entire month of March is 6.36″, such that month-to-date precipitation is currently running 2.40″ above this average.

Reference 2019-20 Precipitation Totals For More Values.

Previous Statements

*A chance of showers and thunderstorms Thursday, amid unseasonably mild air, will give way to likely activity on Friday in advance of a strong cold frontal boundary.

*Strong SW winds will develop Thursday night into Friday, beginning at upper elevations and mixing downward into middle and lower elevations.

Wind gusts of 30-40+ mph will begin Thursday night at upper elevations and mix downward into middle-lower elevations during Friday. Local wind gusts to 50+ mph will be possible.

*A heavy to excessive rainfall potential will exist Friday, with strong rises on streams more likely in locations that received up to 1.00″+ of rainfall into early Thursday.

Much like late Wednesday afternoon into early Thursday (19-20 March), SW flow will add orographic lift to help enhance totals along the Cumberland Mountains (1.11″ of rain was observed at Big Cherry Lake Dam into early Thursday, with 1.01″ on Black Mountain).

Wintry Feeling Conditions Expected Saturday With Cold Daytime Temps

*Much colder air surges into the mountain area Saturday on northerly upslope flow, with low cloud bases and the threat for more dense fog at middle to upper elevations (rime levels will drop from high summits downward into the 2500-3000 foot elevation zone over time).

A brief intrusion of drier air into early Sunday will allow coldest temps to develop in mountain valleys (coldest conditions Saturday will be at highest elevations) with potential for strong low-level inversion formation (coldest conditions in valleys with rising temps on high ridges into Sunday morning).

An exception may be in some lower elevation locations where clearing over wet ground may allow for dense fog formation. Stay tuned for later updates.

*Additional waves of significant precipitation will be likely from late in the weekend through next week. Interaction with colder air at times may need to be monitored for the potential of some frozen forms, especially to the north and northeast.