PNW Migration Update – 21 May 2013

Strong westerly winds at elevation, pockets of rain and generally nasty conditions kept most migrants still headed north grounded last night.  There was a little pocket of birds taking off from the Gray’s Harbor area – probably stragglers of the shorebird and water fowl variety.  They didn’t get very far.  There were some moderate and widespread returns from California’s Central Valley so this isn’t over yet – but close.

The arctic low has moved south and is still dragging in a cold air mass, condensing moisture as it arrives – there’s even snow at higher elevations.  The center is up in BC so we’re getting the westerly winds at the bottom of the trough.  There is a high pressure ridge organizing out in the Pacific but it’s effects are a few days out.

Nationally the migration was heaviest in the northern fetches of the Mississippi Flyway.  The Atlantic Flyway was active in the Mid-Atlantic States.  For details refer to the regional NEXRAD trackers found in the sidebar links.  To take a look at the national migration picture click here where Paul Hurtado has archived last night’s event.

Admin Note:  This is the last update for this season.  I will probably do a final post in June where i’ll put up the intervening local radar loops for documentation.  Other than that — barring some meltdown — TTFN, be back in the fall.

Left click for larger gallery view: