Welcome to the first true migration report of autumn 2015!
Only very light to light migration should be expected tonight, as evidenced by the current radar which shows patchy blue areas, indicating negligible concentrations of most likely less than 100 birds migrating per cubic kilometer - which is not a lot. The wind map (see below) shows that Illinois winds are south-southeasterly tonight which would be prohibiting a lot of movement because southbound migrants rely on northerly tailwinds to migrate.
One should note; however, that there is slight variation in the amount of noise the radar is showing throughout different areas of the state. I believe that the northern two thirds of Illinois should be experiencing very, very limited, if at any, arrivals and influxes whereas the southern third of Illinois should actually expect light concentrations tomorrow morning. This is evidenced by the extremely patchy blue areas in the northern two thirds of the state with light blue radar noise being more widespread in the southern third.
What are some arrivals and influxes to be expected tomorrow and over the next week or so? Go to the Birdcast Migration Forecast for a detailed outlook, but a few species that should be moving in noticeable numbers are Green-winged Teal, Buff-breasted and many other Sandpipers, Northern Waterthrush, Blackburnian, Golden-winged, Chestnut-sided & Black-and-White Warblers, Ovenbird, Warbling Vireo, Rose-breasted Grosbeak, and Veery. Of these species, I have found Northern Waterthrush and Rose-breasted Grosbeak in my neighborhood over the last few days. Another good resource for looking at when certain species arrive and peak in Illinois is the eBird occurence chart which diagrams comprehensive annual reports of these species.
So what should we expect with regards to wind forecasts and probable migration outlooks for the next few nights? Tomorrow (Sunday) night, the storm system that will have passed through from the west during the day will shift winds to being westerly, possibly making for more light-to-moderate concentrations of migrants. Arrivals and influxes should increase nightly on Monday, Tuesday, and Wednesday nights as winds gradually transition from due west to due north by Thursday morning. So, Tuesday, Wednesday, and Thursday mornings might be good for finding new migrants for the season.