Sunday, April 5, 2015

April 5th, 2015

Winds tonight. Click to view live. Note how
obvious the contrast provided by the stationary
front is.
Evening all!

Tonight, winds remain southerly in most of the state. Perhaps due to some of the reasons listed yesterday, however, birds are still not moving in as heavy of movements as they did on the 1st. Overall, the Prairie State is witness to at least light concentrations of migrants in most places, so there may be some visible arrivals and influxes tomorrow. There is one exception to this, which is detailed below.

Unexpectedly, a large high pressure system in Canada pushed further south during the data today, leaving a stationary front smack-dab in the middle of Northern Illinois. On the north side of this front are unfavorable northeasterly winds, and on the south side are favorable southerly winds. While this contrast is beautiful on a wind map, it does mean that migration will be more disrupted in northern  Illinois tonight than anywhere else in Illinois. Currently, it looks like the northerly-based winds are limited to the Chicago area, but this could change gradually at any time. Other places in Northern Illinois are actually receiving more migration than anywhere else in the state. Northwestern Illinois birders should definitely be on the lookout tomorrow, as movements now are pushing toward moderate concentrations.
Tonight's migration. Note that
it's at its heaviest in NW IL

Let's look ahead now. It's forecast that this northerly wind incursion will be pushed back where it came from by tomorrow morning. But don't get too excited. The front is also forecast to come back southward by 7PM tomorrow, and by midnight thereafter, its unfavorable northerly winds are forecast to envelope all of Northern and some of Central Illinois. That's as far as my wind forecast goes, so it looks like we'll just have to sit back and wait for the front to subside. I'll keep you posted.

Central and Southern Illinois are much in the same boat tonight, so I decided to fuse them in tonight's report. Migration, overall, is light in the region tonight, with only slight amounts of disruption due to precipitation in far Southern Illinois. This migration may increase in magnitude as the night goes on, so if you know you'll be up late tonight, be sure to check back on the radar.

The wind forecast for tonight is about as simple; winds are forecast to remain southerly in Central and Southern Illinois until Tuesday night, when northerly winds driven by high pressure will again incur from the north. Until then, let's hope for some good migration.

If you're curious about what you may find out there tomorrow, as always, check out this handy eBird page.

That's it for now, folks! Until tomorrow, good birding!

Note the stationary front over N IL in this surface analysis forecast.
This is the wind forecast that corresponds with the image above.

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