In spite of the weather the birds were able to find a window early in the evening to get a bit further north. When looking at the Reflectivity loop from last night shortly after sunset (03:00 UTC – 20:00 PDT) you will see a flight up the I5 corridor. The localized nature of these storm cells is allowing for some opportunistic advances north, and the SSE winds are aiding in those efforts.
There is a ridge of high pressure behind this current system which may dry things out but will also be bringing winds out of the north. For the migrants its all about timing.
Pacific Northwest Radar: (Click on the links below to open the .gif files in a new window)
Here is Paul’s archived National Radar Composite from yesterday. Widespread migration along the Gulf Coast, up into the Ohio Valley, and along the western flanks of the Appalachians, but shut down most everywhere else.
And here are the weather maps (click on any image to bring up a full gallery view)