I expect a LOT of these beauties will pass through Sunday-Monday at Beamer!!!
As of the forecast right now, I'm guessing Monday could deliver a MONSTER flight of raptors at the Beamer Hawkwatch in Grimsby.
The classic "mid-march" weather may be in effect - high pressure, light winds. (North) Therefore I would expect these two situations:
Sunday - as of right now, winds are forecast to be north at 30kph. It will be VERY cold at Beamer, and the flight may end up totally dead. BUT - the birds are so far behind, they may fly anyways. If they do fly - the fight will be verrry enjoyable (just ignore the cold) - as they ride the updrafts along the ridge. Red-tails and Red-shoulders could put on a show.
Sunday is good weather to get a species like Peregrine Falcon or Northern Goshawk. If snow to the south doesn't totally shut down the flight (plus winds too strong from the north).
Monday is currently calling for winds south at 10kph and 10 degrees. This is THEE day (based on the forecast). I would expect large numbers of several species (Red-tails, Shoulders, Bald Eagles, Harrier's, Rough-legs etc) - and maybe a large flight of Vultures as well.
If a "lake breeze" kicks in, the large numbers may move inland - but a few hundred birds will ride the ridge and give great looks. If it doesn't kick in that much, I'd expect huge numbers to be all over the place (high/low etc). with great diversity. This is the type of forecast that could really make for an incredible day, but it's nearly impossible to predict exactly how the local geographical elements (lake, escarpment) will change the dynamics of a flight.
If you want to see lots of birds, for sure - go both days. If you only have Sunday off (and want to see hawks) - give it a try Sunday. Monday looks best (right now) though. I'll update the comments section of this post over the next 24ish hours if anything major changes with the forecast.