PNW Migration Update – 30 April 2013

Moderate migration over the area this past evening.  We were given the classic “doughnut hole” treatment last night. Watch the radar loop and note the lack of returns close to the signal.  What this represents is an absence of birds at low elevations.  Few birds leaving or landing in the area.  They are, for the most part, about a mile up and not stopping here.

The winds were out of the north for most of the night but not too terribly strong (5 – 10 knots) except along the coast (10 – 15 knots).  Around midnight they dropped off.  I put in a static shot of what happened after that.  From the mouth of the Columbia and Willapa Bay an explosion of birds takes off and heads out to sea to continue their journey north.  We still do not have station level data for the new radar along the Washington coast — too bad, it would be great to get that data.  So you’ll have to do with the static Regional level plot in today’s gallery.  But you might want to head on over to RAP and run your own loop — it’s pretty cool.

This high is proving to be pretty stubborn.  It has pushed the low we saw yesterday north again, relieving some of the strain, lowering the wind speeds, and keeping the arctic air entrainment to moderate levels.  As the low passes to our north we may see some instabilities develop but should present only as cloud cover.  I’m looking for mild north winds and no rain for tomorrow night’s flight.  Migration will continue apace.

Nationally it was a repeat of last night with a few developments.  The Atlantic Flyway had a wind blockage from the Carolinas to New Jersey.  The gulf rim was quite heavy and some fall-out conditions could present in the Florida pan-handle area westward along the squall line.  The Mississippi and especially the Central Flyways were ablaze with birds.  Until they met the storm track running from Nebraska to Wisconsin.  Concentrating events are likely along the southern boundary. (LaPuma is probably peeing his pants in anticipation of today’s possibilities)

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