Sat 24 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, SSE winds with it. Further north, up into BC and off the coast of Alaska, the winds have subsided considerably from yesterday but still do not favor exodus.  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.

Second image is of the surface winds and pressure. Light and variable over land and out of the south off shore.

Third image is a snapshot of the base velocity showing targets moving in random trajectories 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.  There is some NS directional movement along the Columbia north of us.  Probably birds heading to Ridgefield or Sauvie Island so that might be a good bet this morning.  Although the River S unit at Ridgefield is still closed for road repair — until the 28th i believe, so check before you go.

The animated gif with snapshots every half hour of the base reflectivity above radar station RTX shows this small movement as well starting about 10 PM PDST last night.  You can see the density pick up around Kelso and move south along the Columbia from there.   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 7:06 pm pdst.