First image is of the winds aloft at 850 mb (approx 5000 ft). Along the coast, as a cold front advances, there are strong winds out of the south that will keep birds on the ground waiting for the front to pass and take advantage of the north wind in it’s wake. Winds over the PNW are light and variable and pose no impediment to migration but no impetus either. Bottled up birds that are itching to move will take to the skies.
Second image is of the surface winds and pressure. Matching the winds aloft in directionality but considerably calmer.
The RTX radar was down last again night.
(Click on the thumbnails to view the full-sized images.)
Sunset last night was at 7:12 pm pdst.