Monday, December 17, 2012

Potent West Coast Storm Is Our Thursday Night Event

A rather potent winter storm worked onshore into Washington state this morning, spreading high winds, rain, and mountain snows across the Pacific Northwest. The storm system was strong from a pressure standpoint -- with a surface pressure down in the 977 mb range early this morning as the center of low pressure pushed onshore.  While certainly not record breaking for a Pacific storm, it's still nonetheless a pretty potent system, one that will have impacts as it crosses the US over the next three to four days.  Upwards of three feet of snow may fall in the Cascades before snow shuts off fully later on today.

This storm system will move through the country over the next 72-96 hours, bringing the first snows of the winter to Chicago and Milwaukee as it does snow.  These locations are also in a snow drought of sorts -- not having picked up their first snowfall of the winter yet.  That changes for them.  It won't really change for us unless you consider flurries post-storm sufficient criteria.

Thursday night's storm is likely to track northeast through the Great Lakes (after diving into Colorado and pushing across the Plains), with a strong cold front sweeping east with a band of rain.  A wave of energy will organize along the front but will not become the dominant feature until it pushes northeast into New England.  The result will be rain for the region as this front comes through.  Modeling suggests this storm pushes through between 10 PM and 5 AM -- the Euro the slower, the GFS the faster of the two -- but both share the same general outcome for us -- rain.

EURO depiction for Thursday night/Friday AM as storm system pushes through region.

Flurries and snow showers from dying lake effect bands will be possible on Friday afternoon and Saturday as the storm pulls away and colder winds blow in on the heels of the storm system.  It will bring us back to reality and end this mild streak that's in place over the Mid Atlantic but it certainly is not an arctic invasion.