Here’s the radar from sunset last night through 5:00am this morning.

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

As you can see from the following surface map: http://www.rap.ucar.edu/weather/progs/prog00hr.gif, the major frontal system that we’ve been discussing all week is continuing to influence the region from the Gulf of Mexico all the way up into the state of Maine. As the front has pushed eastward, the wind gradient along the boundary has intensified and turned more southerly. The northern portion of the front has also moved further north, allowing more migrants to push up into New England and the Canadian Boreal Forest. As a result of the shifting winds, coastal migration over New Jersey and Eastern New York was minimal last night in comparison to farther west. Virginia, Washington DC, Central PA, and New York State (excluding the eastern portion) all showed heavy migration with birds heading on a general S->N trajectory.

Interestingly, too, was the spatial pattern of birds migrating across New Jersey. If you check out the Fort Dix radar you’ll see that the reflectivity is strongest at a distance from the radar, creating a “doughnut” effect, rather than an even distribution from the radar to the periphery. Since birds flying at lower elevations will be detected closer to the radar (given the shape and angle of the radar beam), this suggests that whatever birds were migrating over NJ last night were doing so at high altitude. This may have been due to more favorable wind conditions farther up in the atmosphere.

For today, expect less birds overall throughout most of New Jersey with the chance of a few new arrivals along the western border of the state. Most of the action took place to our west, so birders in MD, DE, PA, and throughout NY State should see new birds at their spring migrant traps this morning.

Tonight will be the night to watch, as this front clear out to our east and the winds turn southwest before going fully west by morning. Thunderstorms are on tap, and I think it’s possible that we have exhausted a fair portion of our migration-ready birds over the last week; but if birds do decide to migrate tonight we could see a good show along the coast tomorrow morning. Stay tuned and I’ll  keep you updated!
Good Birding

David