Wed 23 May 2012 – PNW Migration Update

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The low pressure system remains offshore to our NW but it is breaking down a bit.  A competing high pressure ridge is organizing off the California coast. We’re still getting the SW winds, but the rain has let up.  Last night local migration was not detectable through the cloud cover.  Usually one can see some sign of migrant bloom between the clouds or on the velocity plot.  Last night – nada.

In the field the listserve was littered with reports from Malheur – a sign of the times.  The bulk of the Phalaropes apparently moved on. Checking in on eBird for Multnomah and Washington Counties arrivals, we find nothing new in the area.

The outlook for migration over the next few days continues to be dependent on the timing and occurrence of rain and, most importantly – a supply of birds.  The wind is forecasted to remain out of the SSW throughout the day.  But as the front moves east and competes with the high pressure ridge we will have an unstable system that becomes harder to predict.

Regionally migration in the Rogue Valley was minimal at best.  Being quite a bit further south they are seeing some northerly surface winds associated with the frontal boundaries.  I’m not sure if that is what is holding up the birds or just the tail end of the season.

The Californian portion of the Pacific Flyway has pockets of heavy migration from San Diego to Redding.  SoCal continues to moderate.

Nationally the weather continues to favor the Central Flyway and portions of the Mississippi Flyway.. We find the birds are still heavily pouring in from Mexico, but maybe not as widespread.  The Great Plains’ radars again have solid returns from Brownsville to Duluth.  Dakotas had a significant decrease in density last night due to some storms.    Overall, the spring fling is winding down and we’re all just waiting for the call of the nighthawks.

As always — For more detailed migration updates in other regions check:

Wisconsin and New Jersey – woodcreeper  by David LaPuma (currently on hiatus – 5/21)
Michigan’s Upper Peninsula – The Northwoods BIRDAR by Max Henschell <- NEW!
New England – Tom Auer’s blog
Florida/SE – Badbirdz Reloaded by Angel and Mariel Abreu
PA/Ohio Valley – Nemesis Bird by Drew Weber
NW Ohio – Birding the Crane Creek by Kenn Kaufman
Arizona – Words About Birds by Tim Schreckengost <- NEW!
New Mexico – Albuquerque Birding by Matt O’Donnell <- NEW!
Continental US – eBird BirdCast Forecast & Report by Team eBird

Also found under NEXRAD Trackers in the sidebar to the right.