Special Update, Tribute in Light: 11-12 September 2013

Andrew Farnsworth The Cornell Lab Sep 11, 2013

Last night’s flight is the Northeastern US was as underwhelming as previously forecast, and the hopes for slightly more favorable though still marginal conditions for birds to move during the night bore no fruit. Widely scattered light movements occurred in most areas of the Northeast, though many of these were probably dominated or masked by local insect and bat movements. For the record, much of the eastern half of the country experienced a similar situation, with high pressure and a warm moist air mass dominating the scene. Note, however, that changes are brewing in the northern Great Plains and western Great Lakes, as a strong cold front marking the arrival of a new and much cooler and drier air mass facilitate moderate to heavy movements in its wake. Thankfully, for most New York City area migrants’ sake, this front will not arrive until several days after the Tribute in Light is complete.

09This evening’s forecast is not favorable for bird migration in the greater New York City metropolitan area. As a slow moving low sits over eastern Quebec, unstable air persists as the warm and moist air mass present over the region for the last few days continues to bring unseasonable temperatures, southerly and southwesterly flow, and the potential for thunderstorms to fire this evening, close to the time when migrant exodus occurs. If winds are lighter than expected and thunderstorms do not fire, there is a chance that some tens of birds at a time could appear in the beam, corresponding to local, light movements; however, given the forecast, even this might be wishful thinking.