23 September 2015 – PNW Migration Update

Neutral conditions of light variable winds and clear skies — moderate migration.

A well organized low pressure system is spinning up in the Gulf of Alaska.  We’ll keep an eye on that as it moves west east because the leading edge will definitely put the breaks on.

Well — i knew it was coming, I’ve reached the end of my allotted memory so i can’t post any loops or images today.  I have a few options that i have to mull over.


22 September 2015 – PNW Migration Update

Welcome to Fall.

Birds were jamming last night!  Decent conditions, light northerly winds on a clear night across the Pacific Northwest.

The grand passage of the Greater White-fronted Geese yesterday – wow!  Probably a once in a lifetime experience. From the Portland Basin to the Southern Coast reports came in of GWFG in the thousands passing overhead.  A remarkable event.

Anyway i added the Seattle radar loop today because it was packed with birds and i don’t think i’ve posted one from there this season.  So here it is, your moment of zen:

Oh, look at the RTX loop and see if you can spot the Barn Swallows going to roost,  Starts around 00:00 UTC.


21 September 2015 – PNW Migration Update

I just got back from a walk around the block, specifically to listen for migrating Greater White-fronted Geese.  They were streaming overhead, flock after flock, non-stop.

Which brings us to today’s radar loops.  The RTX loop is very interesting.  Shortly after sunset there was a small but noticeable flight out of the area for about an hour or so, and then — nothing of note.  That is until around 2:30 AM (PDST) and BOOM!  The sky is just filled with returns up to the 30 dBZ level.  I suspect a majority being Greater White-fronted Geese.

I also threw in the Gray’s Harbor (LGX) loop because this is the largest sustained flight i’ve seen this season from there.

Note the wind map and the favorable winds out of the NNW.


15 September 2015 – PNW Migration Update

In spite of decent conditions, migration in the area remains tepid at best.

So, lets look elsewhere.  Today we’ll look at the national level and one curious spot. Nationally take a look at the Wind map, note the strong flows up the Central and Mississippi Flyways, and then note the paucity of migrants.  The east coast, with milder conditions, dominates the scene last night.  Since we showed Jacksonville recently i’m leaving that out, but it was jamming again last night with returns again pushing the 40 dBZ levels.

So, take a look at the loop from El Paso, TX from last night.  What i am curious about is the ring of returns that pops up for about an hour — just before avian migration takes place.  Look for it in the lower center of the frame over in Mexico.  I’m GUESSING, bats.  But, if anyone knows for sure – let me know.  Whatever they are, there are a ton of them dispersing from a single point.


11 September 2015 – PNW Migration Update

The ridge of high pressure remains in place – sort of.  It has been displaced a tad more out into the Pacific and that may account for the easterly offshore flow.

Whatever the case, migration last night was unremarkable and ended quite early.  I think this is just a pipeline issue as there has been some significant weather up north, probably holding back the migrants.

10 September 2015 – PNW Migration Update


Another solid night of migration.  This high pressure ridge just wants to stick around.  That brings gentle winds out of the north and makes excellent conditions for southbound migrants.

Greater White-fronted Geese, Sandhill Cranes, and more winter sparrows are all being reported in the area.  It’s a good time to get out into the field.

Here it is, your moment of zen:


09 September 2015 – PNW Migration Update

I’m having a bit of trouble using WordPress — it keeps crashing and i am losing my drafts.

This is the third attempt and i’m just going to post the radar and wind maps i intended to comment on.

Update: Here’s a great article on Radar Ornithology that Tom Auer (his web site is found in the side bar) just tweeted.


04 September 2015 – PNW Migration Update

Another solid wave of migrants moved through, and into the area last night.  Not quite as robust as yesterday, but still decent.

The drop in density is probably due to the nature of yesterday’s event.  When migrants are held up for a while i suspect they build up a bit of “pressure”; in both numbers and urges.  So that when the weather conditions change favorably, they kind of pour forth to relieve the pressure.

You can see from the wind map our weak high pressure system is still in place giving us these calm winds out of the north.  It looks like this will persist for a day or two as well.

I put in the National Composite today — take a look at the west side of Lake Michigan!  From Green Bay to Chicago the movement was extreme.  Heavy yellow returns across the board.  To save space i did not put up a loop from either of the three stations, but if your curious what a mega event looks like take a look at Green Bay’s loop on the DuPage Weather Lab.  I did archive the loop and may put it up later if there is nothing going on here.


03 September 2015 – PNW Migration Update

OK this is more better.

With the winds shifting on the shoulder of a weak high pressure system, a bit of the pent up migration urges were released last night. We had a fairly heavy passing last night — even a tiny touch up into the 30 dBZ zone (yellow).  Nothing like Duluth a couple of days ago, but still pretty solid.

For today’s moment of zen we have Cameron’s Winds of the Earth,  the loop from our local RTX station, and a static shot of the National Composite archived over on Paul’s website.

I pulled back on the WOTE snap shot so we can see the line of typhoons out in the Pacific.  Anytime you see red in the Wind Power Density plot, just hope it’s not headed for you.

01 September 2015 – Migration Update

Looking at the wind mapping you can see that the inland pipeline is still being hampered by strong southerlies, especially in BC.  But the strong fliers coming out of Alaska may just hitch a ride out over the ocean and pass up Washington and Northern Oregon.  Eh, who knows.

In any event, migration in the metro area was muted and probably limited to reshuffling.  So lets take a look at the National Composite (thanks Paul!).  Pretty muted, but more widespread — except for this season’s darling – Duluth!

So i cherry picked that loop; and note the EXTREME radar returns way into the 30 dBZ zone, which is off the charts crazy.