Thursday Snow Nowcast at 3 PM: Snow Moving in Faster Than Expected

Well, our models may have had the right idea of the threat of snow, but the recent runs clearly have a serious timing error.    The snow will arrive 4-5 hours earlier than expected.

The latest radar image  (2:27 PM) shows the story--the precipitation shield from the warm front has reached the south Sound.  Once precipitation starts aloft, it takes about an hour to reach the surface (need to humidify the layer below)

Let me show you some traffic cams.

It has been snowing in Portland for hours.

Vancouver

 Longview

Here is the Chehalis Airport

 And finally Centralia.

It should starting snowing at the surface in Olympia by 3PM.  At the current rate of progress, the snow will get to Tacoma around 4 PM and Seattle by 5-5:30 PM.



from Cliff Mass Weather Blog http://ift.tt/2ghf8Kl