Unseasonably Cold Temperatures Will Continue Into Sunday Morning
Minimum temperatures will drop into the 10s to lower 20s in colder locations into Sunday morning ( i.e., in mountain valleys and along the highest mountain ridges above 3300 feet ).
ALERT For Strong SW Winds Developing Along Middle To Upper Elevation Mountain Ridges-Plateaus During Sunday Night Into Monday
An increasing pressure gradient will develop strong ( ROARING ) winds at mid-upper elevations along the Cumberland Mountains from late Sunday into Monday. Mixing of roaring winds will also be possible in lower elevations northeast of the High Knob Massif and Tennessee Valley Divide via enhanced mixing and waves on SW flow ( e.g., Pound-Clintwood area ). Caution is advised.
Overnight Into Sunday Morning
Mostly clear ( increasing high clouds toward morning ). Unseasonably cold. Calm winds in valleys. NW-N winds shifting SSE-SW at 5-10 mph along mid-upper elevation mountain ridges-plateaus into morning. Temperatures varying from the 10s to lower 20s in colder valleys, and along highest ridges, to mid-upper 20s in milder sites.
Sunday Afternoon
Hazy sunshine ( mid-high clouds ). Milder. SSE-SSW winds 10-20 mph, with higher gusts. Temperatures varying from the 40s-low 50s in upper elevations to the upper 50s to mid 60s ( mildest in downslope locations of the Russell-Levisa Fork basins ).
Sunday Night Into Monday Morning
Mostly cloudy. Occasional rain showers. Strong winds developing across middle-upper elevation ridges. Winds SSW to SW 10-25 mph, with higher gusts, below 2700 feet. Winds SW 20-30 mph, with gusts to 40+ mph, on mountain ridges above 2700 feet. Temperatures widespread in the 40s. Wind chills in the 30s along upper elevation ridges.
Monday Afternoon
Partly to mostly sunny. Windy. SSW-SW winds 10-25 mph, with higher gusts. Temperatures varying from the 50s at upper elevations in the High Knob Massif to the upper 60s to middle 70s ( warmest at lower elevations in the Russell Fork and Levisa Fork basins ).
Monday Night Into Tuesday Morning
Rain developing. Windy. SSW-SW winds 15-25 mph, with higher gusts, shifting N into morning and decreasing to 5-15 mph. Mild evening temperatures in the 50s-60s turning cooler into morning with readings dropping into the 40s, except 30s at highest elevations.
Weather Discussion ( April 8-11 )
It is always interesting when spring meets winter amid the mountains, with this recent system not disappointing as a few periods of moderate-heavy rain-sleet-snow were even spiced with lightning-thunder late Friday into the early hours of Saturday.
Heavy Snow In High Chaparral of High Knob Massif – 8:38 PM on April 8, 2016
My friends Joe & Darlene Fields had 2″ of snow depth in the High Chaparral community of the High Knob Massif Friday Night into Saturday AM ( around 2.5 to 3.0″ of total fall ).
High Chaparral sits at an elevation of 3300 feet, or around 900 vertical feet lower than the crest of the High Knob Massif.
Snow Accumulation In High Chaparral At 9:52 PM on April 8, 2016
Total snowfall was a little greater than snow depth as some melting and enhanced settlement occurred on the unfrozen ground of April.
Ground Depth In High Chaparral of High Knob Massif – 9:07 AM on April 9, 2016
Enough snow accumulated to maintain a solid snow cover on upper northern slopes throughout the day of April 9, with snow melting off roads but continuing to cover heads of basins in the High Knob Lake, Big Cherry Lake & Norton Reservoirs at sunset.
Blooms Amid The Snow In High Chaparral – 9:08 AM on April 9, 2016
Snow amounts tapered to 1″ or less below 3000 feet, with Wayne & Genevie Riner reporting 0.3″ at Nora 4 SSE on the Long Ridge of Sandy Ridge. A total of 0.1″ fell in Clintwood with sticking during a thunder-snow-sleet downpour.
These shots were taken just before the moderate-heavy late PM and evening activity began during April 8.
Rue-anemone ( Thalictrum thalictroides ) In Various Stages – April 8, 2016
While more chilly shots, and frost, will be likely in coming weeks, perhaps this may be the coldest until later this year when the 2016-17 cold season begins. Perhaps.
European Model 850 MB TEMP-Surface Analysis At 8 AM Saturday ( April 9 )
Temperatures dropped below zero ( 0 degrees Fahrenheit ) at upper elevations of the High Knob Massif and Black Mountain amid gusts during Friday Night into Saturday Morning. True winter air!
Black Mountain MesoNET Temp-Dewpoint-RH Graphs at 4031 Feet
To put this into better perspective, this was the coldest air in the entire Northern Hemisphere ( relative to average ) for this time of year ( by far the coldest, as illustrated below by anomalies ).
European Model 850 MB TEMP Anomalies At 8 AM Saturday
Focus now shifts to warm air transport and a increasing pressure gradient that will crank up winds yet again by Sunday Night into Monday ( beginning at upper-middle elevations and mixing downward across the entire area over time during this period ).
NAM 12 KM Model 850 MB Wind Field Forecast At 2:00 AM Monday – April 11, 2016
The 850 MB wind field becomes very strong along & west of the mountains tonight into Monday, with 50-60 kt SW wind speeds developing from the Cumberland range west-north. This will generate a favorable settings for ROARING winds within the favored SW Upslope-Downslope flow corridor of the High Knob Landform and downstream locations ( where air sinks, for example, into the Russell Fork Basin ).
NAM 12 KM Model Total Precipitation During Next 84-Hours
Moisture increases aloft with high clouds Sunday and eventually a lowering of cloud bases by later Monday. Showers of rain, not snow, will become likely by late Monday into Tuesday ( during a windy period ).
