Increasing Probability of Lowland Snow Late Thursday Afternoon Through Early Friday

It is becoming increasingly likely that we will see some significant snowfall over the lowlands late Thursday afternoon into early Friday morning, with amounts of 2 to 5 inches being probable before the precipitation turns to rain.

My work tonight is made more difficult by major systems failures at the National Weather Service, slowing of Comcast internet (surprise), and the lack of availability of the UW WRF runs (probably due to the NWS problems).  I will update this blog later when key material becomes available.  But the show must go on.

Thursday afternoon, cold and dry air will be in position over western Washington and a strong warm front will be moving up the coast (see graphic for 4 PM showing low-level temperature, sea level pressure, and winds).  Where you see blue colors the air will be cold enough for snow to reach the surface.

Moisture associated with the warm front will be able to fall through the cold air as snow.   By the next morning, as the warm front and associated low moves northward, rain will spread into western Washington except for Whatcom county and environments where cold air from the Fraser River valley make keep snow around (the situation at 7 AM Friday is shown).

I should have more in an hour when the delayed model outputs are available.

from Cliff Mass Weather Blog http://ift.tt/2h1c0it