I thought i’d put up a series of static shots of the National Composite demonstrating the effects of a large weather system stretching from Michigan to Nebraska.
Note how the birds do not cross the storm line — illustrated by the dark radar returns out in front of the storm track. As the storm moves east you can see little pockets of migrants take flight.
The images were scrubbed from Paul Hurtado’s radar archive. Go on over and watch the whole event unfold. Link found on the sidebar under the Weather section title.