Andy S. asked -

>Can we call on resident Tweeters meteorologist Jack Bowling to help explain
>that triggered this influx. My take on the en masse arrival is the High
>pressure cell, which was off the coast (?), now might have edged
>eastward, placing the interior of the Pacific Northwest into a
>southwesterly flow. This might signal lots of migrants that it was time
>to move.

Bingo, Andy. The relentless storm track from the west "buckled" several
days ago with a strong ridge of high pressure forming along the coast.
This ridge is now moving east of the Rockies which puts Tweeterdom
into a warm southwesterly flow. The simplest way to describe the
situation is that all the birds that were bottled up by the cold west
winds are now riding northwards on a warm southerly wind. Enjoy!

-------
Jack Bowling
Prince George, BC
jbowling at direct.ca