Saturday, December 29, 2012

December 29, 2012 Disorganized, Light Snow Event

Light, intermittent snow has erupted across the metro region this morning.  This event, well-predicted in terms of timing, may fall short in terms of expected intensity.   As the surface chart below shows, the storm is actually two separate low-pressure centers - one spreading rain over the Outer Banks and Tidewater, VA...the other spreading light snow across the northern Mid Atlantic.

The lows are embedded in relatively fast, west-to-east jet stream flow.  Accordingly, they will move quickly through the region today, and the jet stream troughs supporting their development are relatively low-amplitude.   While lacking upper-air support over the Mid Atlantic, the southern low is expected to intensify into a Nor'easter as it tracks away from our region...pummeling the New England coast with heavy snow...and will be named Winter Storm Freyr by The Weather Channel.

With the Atlantic Tidewater storm stealing moisture from the more northern storm, the rapid movement and weak intensity...snow totals will be light across our region.

Here is a more regional view of the two storm systems, as viewed by weather radar:

Adapted from NOAA

The fast, west-to-east jet flow will stick around through the coming week.   When the jet stream "superhighway" runs fast and lacks curvy twists (troughs), intense storms cannot develop at the surface.   The computer models are predicting a bit of storminess during the Wednesday timeframe - but any impact will likely be on the light side. 

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