Fri 23 Sept 2011

First image is of the winds aloft at 850 mb (approx 5000 ft). The cold front continues to move eastward bringing strong, 20 to 30 knot, ESE winds with it. Further north, up into BC and off the coast of Alaska, they’re reaching 60 knots! Not many birds will be moving into that.  The position of this front and it’s slow advance doesn’t bode well for this weekend’s birding as very few new birds will be coming into the area.  So, check the listservers and head out to where the sightings have been reported as those birds will probably still be hanging around.  Smith/Bybee and Sauvie Island probably being the best bets.

Second image is of the surface winds and pressure.

Third image is a snapshot of the base velocity showing targets moving in a general SW->NE trajectory at the speed of the prevailing winds — probably not birds.  Or if they are, they’re just shuffling the deck and not in migration mode.

And it’s wonderful to have an animated gif with snapshots every half hour of the base reflectivity above radar station RTX!   Animation runs from around 8:00 pm pdst yesterday evening through 5:00 am pdst this morning. (Click on the thumbnails to view the full-sized images and animation.)

Sunset last night was at 7:08 pm pdst.