Tues 22 May 2012 – PNW Migration Update

The low pressure system remains offshore to our NW.  The leading edge of this system is bringing occasional rain and SW winds.  Last night local migration was barely detectable through the cloud cover and intermittent rain.  The scattered showers and occasional heavy down pour throughout the valley were enough to discourage widespread movement in our area.

In the field: the listserve was littered with valley Whimbrel and Red-necked Phalarope.  Obviously Sunday’s flight contained these birds.  Large concentrations, up to 350 birds, of the Phalaropes were seen throughout the valley yesterday. Seeing as how there was very little movement last night these birds may still be around today. 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.  The wind is forecasted to remain out of the SSW over the next couple of days.  But as the front moves east we will be exposed to the back side of the system and that means rain and northerly winds.  How that effects migration depends on intensities.  Current forecast has this transition set for Thursday and Friday.

Regionally migration in the Rogue Valley was also limited.

The southern portion of the Pacific Flyway has pockets of heavy migration from San Diego to Redding.  It seems that SoCal continues to moderate.  It appears to be a tapering off of migrant flow, rather than local conditions.

Nationally the weather continues to favor the Central Flyway and the far eastern portions of the Mississippi Flyway extending last night to the Atlantic ahead of the front. 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 Minot.  The western, and especially the northwestern portion of the Mississippi flyway had a significant decrease in density last night due to some 20 – 30 knot WNW winds associated with the back side of the storm.   This is the same pattern as yesterday just shifted a bit further east as the storms and winds move in that direction.

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.