So I guess we'll start with the radar tonight. Blue, dark blue, and a bit of green indicate light to moderate migration, so tomorrow may be witness to influxes of juncos, Snow Buntings, various waterbirds, etc.
But it gets more interesting than that. You see, winds tonight are northwesterly , which are highly favorable for southbound migration. We would expect--although it may be a little late for this expectation to begin with--heavy migration tonight, indicated by giant green spheroids on the radar. There are two reasons for this. The first is pretty simple: we're running out of migrants. The bulk of "Fall" migration will be fizzling out into December when southbound migration in the States could be said to be finished.
The second reason is a little more interesting. Check out the surface analysis. We see a bunch of big H's. This means giant air cells of high pressure are oozing their way into our airspace. Though they may be bringing favorable winds, these, as mentioned before, are truly harbingers of winter at this time of year. They bring cold, harsh air without much lifting capacity to get birds going, and create conditions aloft that birds, especially at this time of year, seem to shy away from migrating in as much as they could be. Hawkwatchers especially will pick up on this, as raptor migration is practically shut down with conditions like these.
So that's that about that. These high pressure systems will take their sweet time in passing by us, and
|Winds predicted for going into|
then will be off east of us by Saturday. We will experience southerly flow tomorrow as we end up on the backside of the high pressure, whose winds revolve clockwise around it. But by Saturday night, Low Pressure System-driven fronts (both warm and cold), are set to pass through the Prairie State, bringing favorable northwesterly winds with it. So if I were to make any predictions on when to expect the most arrivals and influxes, I would put my money on Sunday morning.
Cool. Good luck everyone, and Bon Voyage.