The Potential For The First Widespread Frost-Freeze Of The Season Is Being Monitored For Next Week With An Autumn Air Mass Pushing Into The Appalachians
Although numerous frosty mornings have already been observed in mountain valleys, with local sub-freezing temperatures as well, no widespread frost-freeze has yet been experienced. River valleys that fog up, and a few favored mid-elevation thermal belts, might still be able to remain above freezing. This may be progressive and not long-lived, with above average temperatures returning by late next week into the following week by day. Nights look to continue to be cold, especially in valleys, with large diurnal temp ranges.
Reference My History Of Autumn Color 2017 for an update on color changes & recorded temperatures in the High Knob high country.
Overnight Into Thursday Morning
Areas of dense fog developing in lower-middle elevations. Becoming mostly clear in the upper elevations. Light winds, except W-NW at 5-10 mph, with some higher gusts, on upper elevation mountain ridges. Temperatures varying from 30s to mid 40s in colder valleys at upper elevations in the high country of the High Knob Massif to the lower-middle 50s.
*NOTE – Temperatures Thursday will be cooler than currently in my forecast if a low-level cloud deck develops and does not mix out as currently expected. That remains a small possibility to be noted, especially in locations along & west-northwest of the Tennessee Valley Divide and High Knob Massif.
Thursday Afternoon
Partly to mostly sunny. Deep blue skies above any clouds. Generally light winds. Temperatures varying from low-mid 60s in upper elevations to the low-mid 70s ( warmer in river valleys, especially southward into eastern Tennessee ).
Thursday Night Into Friday Morning
Partly to mostly clear. Areas of dense valley fog. Light valley winds. Winds SE-S at 5-15 mph, with higher gusts, along middle-upper elevation mountain ridges. Large temp spread between cooler valleys and milder mountain ridges, varying from 40s to lower 50s in cooler valleys to the lower-middle 60s on exposed ridges-plateaus.
Friday Afternoon
Partly cloudy. Winds SSE-SSW at 5-10 mph with some higher gusts. Temperatures varying from 60s in upper elevations to the mid-upper 70s.
Friday Night Into Saturday Morning
Partly to mostly clear. Areas of dense valley fog. Light valley winds. Winds S-SW at 5-10 mph, with some higher gusts, along mid-upper elevation mountain ridges. Large vertical temperature spread between cooler valleys and exposed ridges-plateaus. Temperatures varying from the 40s in colder mountain valleys to the upper 50s to low 60s.
Weather Discussion ( Air Mass Changes )
An unseasonably humid air mass following remnants of Nate have been ruling the mountain landscape during recent days. This is going to change, with one transition into Thursday and a much bigger change into next week.
High Knob Massif Webcam – University Of Virginia’s College At Wise
Wednesday afternoon maximums varied from upper 60s in the High Knob Massif to the upper 70s ( 79 degrees in Clintwood ) to around 80 degrees.
Nora 4 SSE on Long Ridge of Sandy Ridge – October 11, 2017
October 1-10 Rainfall
Nora 4 SSE 1.48″
Clintwood 1 W 2.06″
*City of Norton WP 2.74″
Big Cherry Dam 3.60″
Robinson Knob 4.69″
*Precipitation total of 50.56″ during 2017. Upper Elevations in the High Knob Massif have had a general 55.00″ to 60.00″+ this year.
Recent rainfall was welcomed, despite bad timing for the final leg of the Cloudsplitter 100 Mile race, with current totals being nearly as great or greater than observed in September ( Norton measured 2.86″ of September rain ).
European 51-Member Ensemble Mean 500 MB Height Anomalies – Days 6-10
Although a notable cool push of air will be felt next week, the ensemble mean of the European Model group currently suggests it will be progressive with a trend back toward above average temperatures by later next week. The main difference versus this recent pattern being a continuation of cold nights, especially in mountain valleys, with large vertical and diurnal temperature spreads.
European 51-Member Ensemble Mean 850 MB Temp Forecast – Days 6-10
