ALERT For Widespread Dense Fog Continues Into Thursday AM At Middle-Upper Elevations Along & North Of The High Knob Massif-Tennessee Valley Divide – Patchy Fog Possible In Other Locations
Widespread low clouds will continue to obscure middle to upper elevations, with periods of drizzle, into the overnight-morning hours of Thursday in locations along and north of the High Knob Massif-Tennessee Valley Divide on northerly upslope flow. Cloud bases should begin to lift and dense fog-clouds break during the sunrise to mid-morning period on Thursday ( May 19 ).
Overnight Into Thursday Morning
Low clouds. Periods of drizzle. Chilly. Winds N-NE at 5-10 mph, with higher gusts, along upper elevation ridges. Temperatures in the 40s to around 50 degrees.
Partly cloudy or becoming partly cloudy. NE winds generally less than 10 mph. Temperatures varying from the 50s across upper elevations to the middle-upper 60s.
Thursday Night Into Friday Morning
Partly cloudy during the evening with increasing clouds overnight into morning. Winds ESE-SSE 5-15 mph along middle-upper elevation mountain ridges-plateaus. Temps in the 40s to lower-middle 50s ( coolest mountain valleys ).
Showers developing ( especially late ). Winds SE-S at 5-15 mph, with higher gusts. Temperatures varying from the 50s at highest elevations to the middle 60s to lower 70s, warmest at lower elevations in basins of the Russell Fork and Levisa Fork of the Big Sandy River.
Friday Night Into Saturday Morning
Rain with a chance of thunderstorms. Rain may be heavy at times. Winds SE-SSW at 5-15 mph, with higher gusts, along mountain ridges-plateaus below 2700 feet. S-SW winds 10 to 20 mph, with higher gusts, along mountain ridges above 2700 feet. Temperatures widespread in the 50s.
The potential for heavy rainfall amounts is being monitored for the Friday Night-Saturday Morning period. Strong rises on creeks will be possible, given wet May conditions ( 5.00-6.00″+ rain tallies observed during May 1-18 from the High Knob Massif into portions of the Russell Fork Basin of northern Wise & Dickenson counties ), should rainfall become heavy. Stay tuned for updates.
Weather Discussion For May 18-21
Low clouds, showers, and persistent afternoon-evening drizzle created a chilly, damp Wednesday for locations in and north of the High Knob Massif-Tennessee Valley Divide.
It was a particularly nasty day amid upper elevations with dense fog all day long above 2700 feet. This combined with temperatures in the 40s, within the High Knob Massif, to put a true chill into the air on breezy to occasionally gusty northerly winds.
Cloud bases which were on and off the Wise Plateau up through Noon Wednesday dropped to obscure much of the area in persistent, dense fog from 2:00 PM to present ( 10:00 PM ).
Non-radar detectable drizzle has also been a persistent feature.
Although cloud bases were just above Clintwood, the nature of this day was illustrated by a AM MIN of 54 degrees and a PM MAX of 55 degrees ( a mere 1 degree of change on the official National Weather Service MMTS System ).
Higher up, amid middle to upper elevations, the mildest temps were observed around sunrise with a steady drop during the day as winds turned to a northerly upslope direction ( readings falling from 50s into the 40s ).
Wednesday evening temperatures have settled into low-mid 40s amid upper elevations in the High Knob Massif and Black Mountain, with enough wind to make it feel like 30s in gusts along the high ridges.
Official temperatures at and above 2700 feet have not gotten above 60 degrees since May 13, amid an extended period of unseasonably cool mid-May conditions in the mountains.
Focus now shifts to a brief break Thursday before another storm system, taking a cold season track, spreads rain back across the southern Appalachians Friday PM-Friday Night.
Forecast models have not been consistent, from run to run, on rainfall amounts so please stay tuned for updates as a consensus is hoped for on new model runs upcoming through Thursday. The storm track & recent pattern suggests that heavy rainfall will be possible with this system ( especially if Deep South convection does not get “out of hand.” ).