Fri 20 April 20120 – PNW Migration Update

Locally, a  small ridge of high pressure pushed the clouds north and the rains stopped just in time for birds to take to the skies.  They probably didn’t get too far as it was raining throughout the night around Chahalis and points north.  Birds may have put down along this front as they ran into the rain. So, some concentration of birds in that area might be a possibility.  KRTX was in precipitation mode during exodus, so it’s not the greatest look, but most birds appear to be headed up the east counties.

In the field: as it was a steady rain yesterday afternoon i did not get into the field.  The listserves have Olive-sided Flycatchers on the move to our south and a stray Townsend’s Solitaire up on Mt. Tabor.  More notable seems to be the lack of migrants in the northern Willamette Valley.  I’m pretty sure they are all bottled up down in the Central Valley waiting to cross the Siskiyous.

Speaking of which, our regional outlook: Medford finally had some clear weather and very light winds; looks like the birds took advantage of these conditions.  The exodus birds will be finding their way up the southern to central Willamette Valley today, and replacement birds will be abundant as you can see lots of movement to the south on the Regional KMAX composite.  Conditions permitting, this may be the beginning of migration pulses.  A push up over the Siskiyous and then another leg north into the valley.

The forecast is for some really nice weather this weekend.  The challenge to migration will be winds out of the north.  It’s going to depend on the strength of those winds.  If they keep under 10 knots the urge to move north will probably out weigh the expenditure of extra energy.

Nationally: the slow moving frontal system draped across the Midwest again defined the northern boundary for migration. There is still a bit of weather to contend with along the Atlantic so migration is locally spotty.  Heaviest movement can be seen from Texas up into the Ohio Valley.  North of there they run into some heavy weather and concentrating events are quite probable.  The animated loop for last night can be seen here.

For a more detailed discussion of migration back east check out the NEXRAD Trackers found in the sidebar to the right.  And joining the BIRDAR Network is Max out of the “Youpper” Peninsula of Michigan.  You can now find a permanent link to North Woods BIRDAR under NEXRAD Trackers.