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.
Monday Afternoon
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.
Tuesday Afternoon
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.
Wednesday Afternoon
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!
Lonesome Pine Airport In Wise
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 ).
NAM 12 KM Model Total Rainfall Next 84-Hours
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.
European Model 500 MB Height Anomalies Analysis at 7 AM November 28, 2017
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.
European Model 30 MB Forecast At 7 AM December 8, 2017
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!
Previous Discussion
High Knob Massif Webcam – University Of Virginia’s College At Wise
This view illustrates the pattern currently embracing the mountain landscape, dry and mostly clear with cold nights and seasonally cool days.
Arctic Oscillation Index
The first week or so of November was unseasonably mild, and dominated by a positive phase of the Arctic Oscillation, +AO, as noted above on the top graph of observed conditions traced by the black line. Observe also that a shift into a -AO phase occurred shortly after that, and since November 10 the local pattern also changed into the current regime of cold nights, seasonably cool days, and drier than average conditions across the Mountain Empire.
500 MB Height Anomalies During November 10-24, 2017
The -AO as well as a -NAO have been largely acting to counter the impacts of a -PNA Oscillation which would typically generate unseasonably mild conditions.
PRISM Model Analysis of November 1-25 Temps – Courtesy of WxBell Analytics
Instead, the month of November has trended to near or below average in temps from this region northward.
Pacific North American Oscillation
Observe above that the Pacific North American ( PNA ) oscillation has been well down into negative territory throughout November. That is about ready to change.
The 51-Member European Ensembles, The GFS Ensembles, The Canadian ( GEM ) Ensembles, and the Japanese Model are all in rather striking agreement that -AO and -NAO phases will be joined by both +PNA and +EPO ( Eastern Pacific Oscillation ) by the middle to end of next week.
GFS Model Ensembles AO Forecast
If these teleconnection forecasts hold
GFS Model Ensembles NAO Forecast
through coming days this week, the BIG NEWS
GFS Model Ensembles PNA Forecast
will be the shift into WINTER across the eastern USA
GFS Model Ensembles EPO Forecast
by the middle to end of next week.
At this point in time individual model runs will be chaotic, but Ensemble MEANS are more stable and should be used most for guidance since the significance of this upcoming change is not yet being fully resolved by models.
+PNA Courtesy of North Carolina State University Climate Office
The -AO and -NAO phases are looking very likely to continue such that the key player will be the Pacific Ocean and the phases of the PNA and EPO.
Stay tuned for later updates as this pattern evolution is tracked through coming days.
