013016 Forecast

My Forecast For Today ( January 30 )

ALERT For Strong SW Winds Across Mid-Upper Elevation Mountain Ridges & Plateaus From Late Saturday Through Sunday

*State Route 619 remains extremely icy.  Chains are recommended if traveling across the High Knob Massif from the City of Norton to Fort Blackmore.  Hazardous conditions remain on other routes in the area ( Route 237 remains impassible due to snow drifts ).

Overnight Into Saturday Morning

Mostly clear.  A large vertical temperature spread developing between colder valleys and milder mountain ridges into morning.  WNW winds shifting S-SW at 5-10 mph along mountain ridges-plateaus below 2700 feet. W-  WSW winds 10 to 20 mph, with higher gusts, along upper elevation mountain ridges ( especially by morning ).  Temps dropping into 10s in colder valleys with calm winds verses rising readings through the 20s into 30s along middle to upper elevation ridges & plateaus.  Wind chills in the 10s and 20s ( coldest at highest elevations ).

This Afternoon

Mostly sunny.  SSW winds 5-15 mph, with higher gusts, below 2700 feet.  SW winds 10-25 mph, with higher gusts, across upper elevation mountain ridges.  Temps widespread in the 40s, varying from upper 30s to around 40 degrees on northern slopes at upper elevations of the High Knob Massif to 50-55 degrees in downslope locations of the Russell Fork & Levisa Fork basins.  Wind chills in the 20s & 30s across upper elevation mountain ridges.

Tonight Into Sunday Morning

Mostly clear.  Large vertical temperature spread between mountain valleys with calm winds & snow cover verses windy mid-upper elevation mountain ridges.  SSW-SW winds 10-20 mph, with higher gusts, on ridges-plateaus below 2700 feet.  SW winds 20-30 mph, with gusts to 40+ mph, on upper elevation mountain ridges.  Temps varying from 20s in colder valleys to the 30s & 40s along exposed mid-upper elevation ridges & plateaus ( tending to rise along highest mountain ridges into morning ).


Weather Discussion ( January 29-30 )

Reference my 012916 Forecast discussion for a recap of my first missed snow forecast of this season, at least for the High Knob Massif & Norton-Wise area, with reasons behind the miss.  It is indeed refreshing to have a weather source that admits when a wrong forecast was made.  It is good to miss a forecast and to admit to it, as that promotes advancement in the science.
That last statement may sound insane in this world, but actually is part of the very foundation of the scientific method where “critical” thinking is and should always be promoted.  No human nor supercomputer will ever make consistently perfect forecasts.  Is a “perfect” forecast even possible?  If you think so, then maybe it is time to review some scientific principles!
High Knob Massif Webcam
High Knob Massif Webcam – University Of Virginia’s College At Wise

A clear sky featured a beautiful close to TGIF as night fell upon snow cover that remains widespread across the area from the High Knob Massif north ( and no doubt, in some other directions too ).  A high water content pack of snow that will not magically disappear, especially on northern slopes where it will take some time to all melt away.

*That is why I keep the slick & hazardous road statement at the beginning of this forecast, as no one should think they can jump into their car and drive up to the High Knob Lookout on Saturday like during a late spring or summer day.
Unless State Route 619 has been worked ( Friday ) again, it remained extremely icy with chains required for safer travel between the City of Norton and Fort Blackmore during Jan 28.  Some roads, such as Route 237, remained blocked by drifts.
NAM 12 KM Model 850 MB Wind-Temperature Forecast
NAM 12 KM Model 850 MB TEMP-Wind Forecast – 7 PM Saturday

Focus now shifts to a January Thaw weekend with ideal conditions in comparison to a week ago.  However, as my friends who live along ridges in Wise, northern Scott, and Dickenson counties constantly remind me, there will be a factor ( WIND ) that will make this less than pleasant.

NAM 12 KM Model 850 MB TEMP-Wind Forecast
NAM 12 KM Model 850 MB TEMP-Wind Forecast – 7 AM Sunday

As is so often the case, it’s difficult to get “warm” in the mountains at this time of year without cranking up winds which act as a great transporter of warm air from southern latitudes ( wind being a direct response to an increasing north to south temperature gradient ).

NAM 12 KM Model 850 MB TEMP-Wind Forecast
NAM 12 KM Model 850 MB TEMP-Wind Forecast – 1 PM Sunday

The NAM Model group and European Model are predicting winds around the summit level of the High Knob Massif to increase into the 40-50 knot range during Saturday Night into Sunday Night, with speeds tending to increase today ahead of this low-level jet of stronger winds.  This will, of course, make conditions feel chillier than air temperatures show across middle-upper elevations ( especially ).

Winds have already made the SW turn up top and are generating chill factors tonight that are making high crestlines feel like the colder valleys down below where drainage flows continue.
Black Mountain MesoNET at 1:45 AM
Black Mountain MesoNET at 1:45 AM
Wind chills and the effect of them are essentially never mentioned in most forecasts outside of arctic outbreak periods.  As residents of the mountains know well; however, this effect is important in much more of the year than most would like and is a near constant factor throughout the cold season from mid-late autumn through the early-mid spring ( i.e., October-April ).
Mean Annual 925 MB Airflow Trajectories
Mean Annual 925 MB Airflow Trajectories

The SW air flow trajectories forecast through this weekend will correlate well to mean annual winds, such that affects of this type of flow are well documented in my climatology.

This shows a tendency for cooler conditions from the Tennessee Valley Divide and High Knob Massif southwest, on upslope flow and rising air, verses milder conditions to the northeast on downslope flow and sinking air.

MAX temperatures in Jonesville to Big Stone Gap and Norton-Wise tend to be cooler under this type of flow than communities such as Pound, Clintwood, Haysi, and Grundy.  Under these conditions it is not unusual for temps at the summit level of the High Knob Massif to be as cool as the highest peaks in the southern Appalachians.

Beyond this weekend an initial wave of rain will become possible Monday ( February 1 ) in advance of a major storm system that will be lifting northeast from the lee of the Rockies into the Upper Midwest and Great Lakes during Ground Hog Day-Wednesday of next week.

A strong pressure gradient associated with this major storm will crank winds back up across the mountains, with potential for a mountain wave event on S-SE flow ( precise flow trajectories and inversion levels aloft are yet to be determined ).
An outbreak of severe thunderstorms, with possible tornadoes, will need to be closely followed west of the Appalachians as it approaches the mountains late Tuesday into early Wednesday.
European Model 500 MB Height Anomalies
European Model 500 MB Height Anomalies – 7 PM Tuesday ( February 2 )
Reference my latest Extended Outlook for trends beyond this time as winter is likely to return with a vengeance by the second week of February ( with much going on in the Northern Hemisphere ).

Have a great Saturday.