Mountain Area Forecast ( Nov 27-29 )
Overnight Into Monday Morning
Clear. Cold. Large vertical temperature spread developing between cold valleys and “milder” ridges-exposed plateaus. NW winds 5 to 10 mph, with higher gusts, along mid-upper elevation mountain ridges. Temperatures dropping into the 10s to lower 20s in valleys versus upper 20s to lower 30s on exposed mountain ridges-plateaus ( 10-15 degrees in coldest valleys of upper elevations ). Wind chills in the 10s to lower 20s on highest mountain ridges. A smoky smell to the air in portions of the area from SE Kentucky wild fires.
Sunny. Light winds. Temperatures varying from 40s to around 50 degrees in upper elevations to the mid-upper 50s to around 60 degrees.
Monday Night Into Tuesday Morning
Clear. Rapid evening temperature drops in mountain valleys with a large vertical difference developing between cold valleys and milder mountain ridges-exposed plateaus. Winds SSE to S at 5-10 mph, with higher gusts, on middle to upper elevation mountain ridges. Temperatures varying from upper 10s to upper 20s in mountain valleys to the upper 30s to lower 40s on exposed ridges & plateaus.
Mostly sunny. Winds S-SSW at 5-10 mph, with some higher gusts. Temperatures varying from 50s in upper elevations to the upper 50s to lower 60s.
Tuesday Night Into Wednesday Morning
Mostly clear. Rapid evening temperature drops in mountain valleys with a large vertical difference developing between cold valleys and milder mountain ridges-exposed plateaus. Winds SW-W at 5-15 mph, with some higher gusts, along middle-upper elevation mountain ridges. Temperatures varying from 20 to 25 degrees in sheltered valleys to the lower-mid 40s on exposed ridges-plateaus.
Mostly sunny. Light winds. Seasonally mild. Temperatures varying from lower 50s in upper elevations to the low-mid 60s at middle-lower elevations.
Wednesday Night Into Thursday Morning
Mostly clear to partly cloudy. Rapid evening temperature drops in mountain valleys with a large vertical difference developing between cold valleys and milder ridges. Winds SSE-SW at 5-10 mph, with some higher gusts, on mid-upper elevation mountain ridges. Temperatures varying from 20s in colder valleys to the low 40s on ridges-exposed plateaus.
Thursday Morning Through The Afternoon
Increasing clouds with a chance of rain showers developing by mid-late afternoon. Winds SSW-WSW at 5-15 mph, with some higher gusts. Temperatures varying from 40s to mid 50s ( coolest in upper elevations ).
Confidence of a Major Hemispheric Pattern Change Across North America is increasing for mid-late portions of next week, centered on December 6-9, with a shift to colder, wetter conditions. Potential for extreme cold is also being followed.
Weather Discussion ( Dry & Chilly )
Overnight Wednesday Update
This current weather pattern continues to feature cold nights in valleys and seasonally cool to mild days. I have to say seasonally cool since days are now so short that by the time deep valleys warm from such cold nights the amount of time for “mild” conditions is now very limited before local sunset ( defined as when the sun slips beneath the mountain horizon ) causes temp drops to begin again!
I show Lonesome Pine Airport obs above since it should be pointed out that all is not as it may appear when it comes to the Wise Plateau, with large temp variations many nights on the plateau itself.
Monday evening, as an example, had similar temperatures reported at the Airport but when I left UVA-Wise around 9:15 PM the temperature was in the 30s ( only 1.5 air miles from Lonesome Pine Airport ) and cold enough for frost to begin forming in places near the old J.J. Kelly High School in Wise ( 2.1 air miles from the Airport ). This is typical unless winds are gusty, such that the Airport temp is often most reflective of highly exposed locations in Wise ( this is why I frequently use the wording of “exposed plateaus” in my forecasts since this also applies to the Sandy Ridge area ).
SW winds have been more gusty, especially at mid-upper elevations, Tuesday evening into this early overnight of Wednesday such that sheltered valleys are now generally coldest ( 26 degrees in Clintwood at 2:50 AM Wednesday ).
Rainfall amounts continue to look generally light with the Thursday afternoon-night weather system. Clearly a main focus remains on next week for a major pattern change that is already taking shape.
The big bulls-eye height anomaly over the Aleutians which had been positive through most of Autumn 2017 has now been replaced by a negative anomaly ( above ), as positive heights with Greenland Blocking continue to mature.
Reference My 110417 Forecast Discussion for more details.
A shift of the Stratospheric Polar Vortex into Eurasia by the start of Week 2 in December is signaling that a cross-polar flow could form, with potential for extreme cold to come into play to radically change the weather pattern across eastern North America. Winter is just around the corner!