06 May 2015 — PNW Migration Update

Moderate levels of migration last night trickling off as a little rain started moving through and putting a damper on continued flight.  Could be a good day to check your favorite patch in the Metro area.  There could be a concentration of birds from the pile up that the rain can cause.

No word on the Western Wood Pewee or Willow Flycatcher yet.

08 Apr 2014 PNW Migration Update

Two in a row.  Clear, calm, with supporting south winds.  Migration is accelerating.  Black-headed Grosbeaks and Orioles are on their way.  Tanagers, Kingbirds and everyone’s favorites – the Empids can’t be far behind.

Another 20+ dBZ night up and down the Pacific Flyway.

08 Apr Base Reflectivity - Portland (KRTX)

08 Apr Base Reflectivity – Gray’s Harbor (KLGX)

08 Apr  Base Reflectivity - Seattle (KATX)

Here is Paul’s archived National Radar Composite from yesterday.  From the Rockies eastward migration was shut down except in a few pockets along the Gulf.  With a really nice flight across the FL Straits.  Hope they make it.

Badbirdz has a great update from Florida called Weather and Birds.  Angel & Mariel discuss “Fallout” conditions from the perspective of the birds.  Check it out, it’s worth the read even if you already know everything.

And here are the weather maps (click on any image to bring up a full gallery view)

17 Mar 2014 PNW Migration Update

All systems were working against north bound migrants last night.  The low pressure system quickly moved through bringing quite a bit of rain and, more adversely, north winds on the back side of the low.

All adding up to a non-event.  It’s looking like tonight may be more of the same.  Probably without as much rain but the winds may continue out of the WNW putting a damper on large scale movement.

Here are the radar loops from last night.  I added KMAX (Medford) because it is quite illustrative.  We see the tail end of the Sat/Sun flight and then the beginning of last night’s flight being shut down by the approaching weather system.  Had the flight had the time to build to max density and then run into that storm it would have created classic “Fall Out” conditions.

17 Mar Base Reflectivity - Portland (KRTX)

17 Mar Base Velocity - Portland (KRTX)

17 Mar HC - Portland (KRTX)

17 Mar HC - Medford (KMAX)

Here is Paul’s archived National Radar Composite from last night.  Nice flight across the Florida Straights and partly up the state until they are met by a major system.  Maybe Badbirdz will put something up on that today.

Here are the weather maps:

25 September 2013 Migration Report

In the face of squall lines and light but variable winds migrants once again picked their way south.  Confronting dicey weather inland there is the possibility of migrant concentrations where they just give up and put down for the night.

Moderate to heavy migration can be seen along the Washington coast – Gray’s Harbor could be smoking today.

The Jet Stream has dissipated the low i was watching and it will probably clear the area and spin up a high pressure ridge behind it.  That will bring in some northerly winds, clear the skies and grease the skids for southbound flights.

Here is the local KRTX Reflectivity loop
Here is the local KRTX Velocity loop (so you can see there really is directional movement in between the squall lines)
Here is the Regional Composite

I haven’t posted one of these lately but the flight down the Central Flyway last night was massive.  Paul’s archive is off line due to server problems so:
Here is the National Composite

PNW Migration Update – 01 May 2013

Migration started out heavy but only lasted the first hour or so as birds left the area.  Throughout the rest of the night densities dropped to moderate levels.  Strong flight offshore again last night which can be seen in the Regional Composite.

As the low was pushed to the north our high pressure ridge shifted a bit south to accommodate.  We had light and variable north winds which really didn’t deter our avian companions.  The drop in density is probably just a lull, but there are plenty of birds headed our way.

Nationally, a storm line across the Great Plains kept the Central Flyway shut down.  Continuance migration behind the squall line can be seen and fallout conditions will exist along the leading edge.  The Mississippi Flyway was open from Texas north and the Mississippi and Ohio river valleys were packed with birds.  The Gulf coast from Texas to Mississippi was the hot spot again and there are localized storm cells that may cause local fallout conditions.  The Atlantic Flyway was active only  in localized parts of New England.  By regional standards the Pacific Flyway was quite active.

PNW Migration Breaking News

It’s as close as we ever get to actual fallout conditions here in Portland.  I don’t have the full report images yet but will post them later.

Take a look at the static Base Velocity plot from 9:04 PM PDT (04:04 UTC) last night.  The blue stippling to the south of our area are migrants headed north.  That big solid yellow mass they are running into is the rain cells that have moved in over night.  As the birds hit  this road block they will put down and look for shelter. This continued for an extended period so we have a pile up of birds in the area.

It’s still on the early side of migration so diversity will probably be limited but the numbers of birds should be quite high – relatively.  It will also increase the odds of detecting the vanguards of later migrants by concentrating them instead of having them disperse across the landscape.

Lest i create the wrong impression here — this is not High Island on the Texas Coast folks.  This is one tiny patch on the Pacific Flyway.  The birds that are putting down in our area tonight haven’t been in the air for 18 hours like trans-gulf migrants have.  Our “fallouts” are matters of inconvenience rather than necessity.  But it is an event none-the-less and i am going to my tiny patch for a look-see early this morning.