First image is of the winds aloft at 850 mb (approx 5000 ft). As the low front slides further to the northeast the winds are turning more from the WSW.
Second image is of the surface winds and pressure. Lighter than aloft and with the same trajectory.
Third image is the animated gif with snapshots every half hour of the base reflectivity above radar station RTX. The radar was in precipitation mode last night. No appreciable flight can be seen last night. Moderate rain was present before sunset and steadily continued up until midnight. However there is no sign of any flight in between the storm cells. So, no new birds, and those that are here, remain.
If we can get that cold front to move east then we’ll have the north winds along the trailing edge move those northern stragglers down the flyway.
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 6:45 pm pdst.
Below is a snapshot of the national radar mosaic. Look back at the 850mb winds and note the stationary cold font that has hung around the mid-Atlantic states has finally moved off to the east and with the NNW winds come the migrants. While in the Central and Mississippi flyways a strong southerly wind, 50 to 60 knots over Nebraska and S. Dakota, keeps the migrants out of the sky.