City is still looking for a 60-degree April day

Temperatures on Wednesday, benefiting from an abundance of sun and a
gusty west wind, made a run at 60 degrees at Libertyville, the Chicago
area's "warm-spot," where the high reached 58 degrees. But at the city's
official observation site, O'Hare International Airport, the 55-degree
high, though the mildest to date this month, was 5 degrees short. Nine
60-degree days are on the books in Chicago in 2009, yet not one has
occurred this month-and that's unusual. Since observations began in 1928
at Midway Airport, 67 of the past 81 years-83 percent of them-have
produced at least one 60-degree or higher April temperature by now.
It's not out of the realm of possibility that an easterly lake breeze,
expected to develop Thursday afternoon, might converge with the lighter
winds expected to dominate inland areas a good part of the day.
Converging winds, even with the comparatively low velocities predicted
Thursday, may be just enough to boost temperatures a few degrees through
"compressional warming" and send a few sections of the Chicago area into
the low 60s.
But jackets and sweaters are the order for the day along Lake Michigan
where an initial temperature romp into the 50s could be followed by a
pullback to the 40s as lake breezes get going.