I could have just as easily titled this one “the inequalities of cold fronts II”. 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.

West and southwest winds built in yesterday across the Northeast and mid-Atlantic. I think the clearest evidence of the effect this had on migration can be seen in the regional composite. What I see when I view the loop is very light migration over most of NY and New England, with a larger flight over New Jersey, and much heavier migration from the Delmarva south and west (with another big flight also extending up into the western Great Lakes region). Southern New Jersey, then, represents the cutoff between little migration and what you would typically expect following a strong cold front. This is due mainly to the northwest winds which persisted to our south last night. The question now is how this will play out in terms of birding this morning.

Looking at the New York radar, it’s clear that little was moving last night, but what was on the wing appeared to be heading out over the Atlantic on stiff westerly winds. The Fort Dix radar showed higher densities of birds also on a similar WNW -> ESE trajectory, suggesting that birds were being pushed down along the east coast. Dover was clearly different, showing much more NW->SE trajectory at lower velocity, suggesting that birds were able to compensate for the wind direction given the lower wind speed over the Delmarva. So, expect birding conditions to be best in the southern half of the state, as most birds were moving downstate overnight with little replacement into the north. Coastal hotspots will be best today and the lighter winds should make it easier to find birds. Sandy Hook has good wind conditions once more (west at 9 kts) but I’d expect little new birds arriving today. Cape May will be a best-bet given its location at the southern tip of NJ and the favorable winds this morning. Still, will it be a better flight than yesterday?

Good Birding

David