Weather Headlines
ALERT For A Messy System Tuesday Morning With Varied Impacts From South To North Across the Mountain Area.
4:30 AM Update: Freezing rain and sleet at Clintwood 1 W changed to heavy snow with 30 degrees as of 4:30 AM.
Very large, silver-dollar size flakes indicate a isothermal profile is developing and a heavy snow band is trying to form, but some sleet is mixing in as well in Clintwood.
A combination of heavy snow and sleet is falling on High Knob, with 30 degrees at the summit levels of Eagle Knob and adjacent Black Mountain. In between 4000 and 1600 feet air temperatures are 34 degrees in Wise at 4:30 AM.
Accumulating snow will be most likely along and north of a Hazard, KY to Hurley, VA line with 2″ to 4″ within the main snow band (locally higher amounts possible).
A dusting to 2″ will be likely south of this line to the High Knob Massif & Tennessee Valley Divide. Heavier amounts, up to 3″ or more, will be possible in upper elevations of the High Knob Massif.
The above is the best forecast currently possible given a high amount of uncertainty in an evolving system.
Updated Discussion
A problematic forecast period is upcoming into Tuesday morning as a fast developing and moving system will be crossing the Appalachians.
For locations along a Pikeville, KY to Elkins, WV line the forecast is relatively easy: Snow. For locations southeast of a Pikeville to Hazard line in eastern KY the forecast has become problematic with warmer air trying to nose into the system around 5,000 feet. Yet, current temperatures are colder than models predict.
Models have trended downward for locations around Norton-Wise, with amounts varying from 0.2″ to 1.4″ in the latest runs as the bulk of precipitation is now being forecast to fall as a cold rain or rain-snow mixture.
The general model trend has been for a northward shift (NW to NE) in the axis of heaviest snowfall.
A notable problem is that current temperatures are colder than models predict and low-level air remains dry with substantial evaporative cooling potential.
This increases concern that models are not fully resolving the cooling potential, such that snowfall amounts could end up higher than indicated now, especially at upper elevations above 3000 feet.
Previous Discussion
*Accumulating snow will be possible Tuesday with a passing upper air disturbance and cold air aloft. The greatest amounts are likely at middle-upper elevations as well as beneath the axis of heaviest snowfall.
While most of the snow accumulation occurred at upper elevations into January 5, a more widespread coverage is expected Tuesday with a combination of early morning onset, more moisture & moderate-heavy snowfall rates.
Extended Forecast Period
*A persistent SW upper air flow is forecast to develop during the January 9-15 period with a heavy to excessive rainfall potential across the lower Ohio Valley, Tennessee Valley and southern-central Appalachians.
An atmospheric river type of setting, anchored by high pressure centers over the eastern Pacific and western Atlantic oceans, is expected to transport Pacific Ocean and Gulf of Mexico moisture across the region with a heavy to excessive rainfall potential.
This heavy rainfall setting will be supported by anomalous January warmth and humidity, with embedded convective rainfall acting to complicate the setting to enhance the flood and flash flood potential.