[cobirds] Good migration kick tonight

CoBirders,

I have heard the conversations so far about this being a slow migration pattern.  I agree it has been a slow migration thus far, but I would propose that it is because our upper-level wind patterns (about 1.5km up from the ground) haven't been ideal for migration except for birds that fly on thermals (think raptors, cranes, and pelicans) or really strong fliers (geese).  Be careful when expressing that this is climate change in action.  We cannot make a statement from a single season without comparing it to other seasons and MANY other years quantitatively.

Tonight may be a good to great night though for other more wind-dependent migrants (think smaller birds).  Most of the fun will be WAY farther south and east than Colorado, but we should see some migrant turnover.  

Take a look at the follow map for 9pm tonight to see what I mean:

http://earth.nullschool.net/#2015/10/16/0300Z/wind/isobaric/850hPa/orthographic=-95.62,41.72,1883

You can see the north winds coming out of Canada and wrapping back into the Front Range of the Rockies here in Colorado.  But it gets even better as you go further along in time:

12am tomorrow:

http://earth.nullschool.net/#2015/10/16/0600Z/wind/isobaric/850hPa/orthographic=-95.62,41.72,1883

3am tomorrow: 

http://earth.nullschool.net/#2015/10/16/0900Z/wind/isobaric/850hPa/orthographic=-95.62,41.72,1883

6am tomorrow:

http://earth.nullschool.net/#2015/10/16/1200Z/wind/isobaric/850hPa/orthographic=-95.62,41.72,1883

So you can see overnight we are looking at some winds coming from the north and wrapping back into the Front Range area.  The mountain barrier is a great concentrator of birds in this case.  So look along the Front Range at local hotspots to see what comes.  It should get cloudier as the night goes on, but I don't expect that the clouds will be low enough to drive nocturnal flight calling down low enough in altitude to make a huge showing tonight.  The nocturnal migration/calling should be strongest in central Colorado initially, then transition down the Front Range as the night progresses and the system moves more to the east and south of us here in Colorado.

If you want to watch other locations (arm-chair birding) for strong migrations or huge numbers of birds, I would look in the northern Texas/Oklahoma area for the greatest concentrations as well as anywhere along the front to the east and eventually northeast of that along a arching line from around Arkansas to Maine where the birds will be more dispersed, but movements will definitely be occurring.  For a closer range possibility, look in New Mexico where the concentrations won't likely be high, but they could see some more eastern species show up along their mountain corridor than usual.  

If you want to get really interesting with this, dig into the radar imagery after dark and see if the radars light up along the areas of north winds tonight.  You can see a nice US-sized view here: http://weather.rap.ucar.edu/radar/displayRad.php?icao=KUSA&prod=bref1&bkgr=gray&endDate=20151015&endTime=-1&duration=1

Hope you have a chance to bird tomorrow or overnight.  Report back as needed.  Would love more data about whether this confirms or not.  Like any forecast, this isn't perfect.

Bryan Guarente

Instructional Designer/Meteorologist

UCAR/The COMET Program

Boulder, CO

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