Mountain Area Forecast ( Oct 19-22 )
Showers & Possible Thunderstorms Will Increase Into Early Hours Of Friday. Much Colder Air, With Falling Temperatures Are Expected Friday Into Saturday AM.
*The first snowflakes of the season could fall at highest elevations by Friday Night into Saturday Morning ( with light riming on peaks in freezing fog by Saturday AM ).
Below freezing temperatures are expected at highest elevations by Saturday morning, with a heavy frost-freeze developing in many mountain valleys by Sunday morning ( below freezing temps ).
Middle elevation mountain ridges and exposed portions of plateaus will have limited frost with mixing and generally above freezing temperatures. Locally dense fog will be possible along major lakes and rivers-wetlands.
Overnight Into Wednesday Morning
Partly cloudy. Breezy-gusty along ridges. Local areas of valley fog. Winds SSW-SW 5-15 mph, with higher gusts, along mountain ridges-plateaus below 2700 feet. SW to WSW winds 10-20 mph, with higher gusts, on mountain ridges above 2700 feet. Temperatures varying from 40s to lower 50s in cooler mountain valleys to upper 50s to lower 60s along exposed ridges-plateaus.
Partly cloudy. Unseasonably warm. Winds SSW-SW 5-10 mph, with some higher gusts. Temperatures varying from upper 60s to lower 70s in upper elevations to the upper 70s to lower 80s ( warmer south into the Great Valley ).
Wednesday Night Into Thursday Morning
Partly to mostly clear. Winds SSE-SSW 5-15 mph, with higher gusts, along mid-upper elevation mountain ridges. Temps varying from 40s to lower 50s in cooler mountain valleys to the lower-middle 60s ( warmest along exposed ridges and plateaus ).
Partly-mostly cloudy. Unseasonably warm. Chance of a shower. Winds SW 5 to 10 mph with some higher gusts. Temps varying from mid-upper 60s in the upper elevations to mid 70s to around 80 degrees ( warmer south into river valleys of the Clinch & Holston ).
Thursday Night Into Friday Morning
Showers & thunderstorms becoming likely. Locally heavy rain. Gusty SW winds shifting to NW by morning at 10-20 mph, with higher gusts. Temperatures dropping into the mid 40s to middle 50s by morning ( coldest in the upper elevations ). Wind chills dropping into 30s & 40s on mid-upper elevation mountain ridges by morning.
Mid-Morning Friday Through The Afternoon
Nasty & colder. Showers & drizzle. Low clouds with dense fog across the upper elevations. NW winds 10-25 mph, with higher gusts. Temperatures falling into the mid-upper 30s at upper elevations and into the 40s to around 50 degrees at lower-middle elevations ( along and north-northwest of the High Knob Massif-Tennessee Valley Divide / milder lee of mountains ). Wind chills dropping into the 20s to lower 30s at highest elevations, with middle 30s to lower 40s below 3000 feet in elevation.
Friday Night Into Saturday Morning
Gusty & cold. Showers & drizzle at lower-middle elevations, with a mix or snow showers at highest elevations. Dense fog above 2700-3000 ft. NW winds 10-20 mph, with higher gusts. Temperatures varying from around 30 degrees at the summit level of the High Knob Massif to middle 30s to lower 40s. Wind chills varying from 10s to lower 20s across upper elevation mountain ridges to the upper 20s & 30s at lower-middle elevations ( below 3000 feet ).
*Skies Friday Night may develop breaks lee of the mountains into the Great Valley, with gusty conditions, and little to no precip on downsloping NW winds.
Weather Discussion ( Strong Front )
A large vertical temperature spread is being observed between exposed ridges-plateaus and colder valleys in early hours of the overnight on this Thursday.
As I expected, a strong inversion has formed with deep, sheltered valleys in low-mid 50s at Midnight versus readings still in mid 60s to around 70 degrees along exposed mid-upper elevation ridges.
This update mainly addresses the push of cold air expected to hit Friday into this weekend, with little to no changes in my previous forecast through Thursday.
Strong height falls continue to suggest that a nice band of showers and thunderstorms will form along-ahead of the cold front later Thursday into early hours of Friday.
NOTE this will tend to bring down many leaves into Friday, so be cautious of slick places on roadways that may be leaf covered.
High-resolution short-range models continue to be in good agreement with the European Group in forecasting showers and downpours, with embedded thunderstorms, to arrive by late Thursday into early hours of Friday.
A sharp temperature drop follows with reading sliding into the 40s in Norton-Wise during the day Friday, with 30s at highest elevations atop the High Knob Massif. Gusty NW winds will make it feel even colder. A WINTER COAT will feel good Friday, especially by later in the day.
While the first snowflakes continue to look likely in places along the high Appalachians, the big story for most will be this nasty temperature plunge Friday into Saturday that will make conditions ( in wake of unseasonable warmth ) feel like a summer jump into winter. Get ready!