PNW Migration Update – 06 May 2013

Due to a power supply failure on my workstation i was unable to update the blog yesterday.  Today, without much commentary as i catch back up, are the Reflectivity loops from the past  few nights.

Only local comment: if you watch all of the loops, note the unusual density of east to west migration over the coast range over the weekend.  Birds were moving out of the Willamette Valley to the coast.  I don’t recall seeing that in past years and would love to hear of any hypotheses on it’s derivation.  HEAVY movement last night.  Late evening development as the winds switched around and came out of the south.

Last night — oh to be anywhere along the Central Flyway!

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2 thoughts on “PNW Migration Update – 06 May 2013

  1. Strong east winds all day Saturday through the night. Were the birds simply following the wind? Thanks for your blog, wonderful to see the loops, and the migrations therein.

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    • motherheidi: the strong east winds are my guess as well. Birds are very keen to move with the wind and take advantage of any movement north. Even slight cross winds will push them from one side of the valley to the other. If you study the loops and 850mb winds you will see more birds on the east side of the river with winds that have a westerly component and visa versa.

      Thanks for the kind comments and enjoy this season’s migration!

      greg

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