Last night and early this morning we saw the latest cold front move over the region and out to sea. While migration was apparent throughout the evening over western NY, the east coast experienced only a small 9th-inning rally once the winds turned WNW today. Here’s the radar from 7:30pm last night through 5:30am this morning.

Frames are every 1/2 hour. Click on the thumbnail to view the full-sized animation.

Check out the regional composite where you can visualize the migration event occurring early in the night to our west, and moving eastward behind the passing frontal boundary. Looking at the individual velocity loops for DE, NJ and NYC you can seen that for most of the night target direction was SW->NE. As the front pushes offshore, though, you can see the trajectory of those targets turn clockwise until all are moving from the NW->SE. Looking back at the reflectivity you can see that the early images are made up primarily of dense precipitation, while the later ones (where the direction of movement becomes NW->SE) are dominated by light to moderate bird migration.

Birding-wise, this migration event is probably too small to produce any significant concentrations of birds, although because of the NW nature of the winds expect coastal migrant traps to be the best bet for picking out new birds. I expect Cape May to harbor a few new arrivals this morning… although, if you’re planning a quick work-week excursion, I would head for the coast tomorrow morning when a much larger flight is expected. On that note, stay tuned for a twitter update tonight as this should be the first big flight of the season!

Good Birding

David