Canadian high pressure building into the Plains brought an unseasonably cool airmass southward into the Midwest yesterday. Once daytime cloud cover faded away and winds diminished, the very dry airmass was able to cool quite efficiently. As a result, overnight low temperatures dropped into the upper 40s and lower 50s across much of central and southeast Illinois. Record low temperatures for July 28th were established at Peoria, Springfield, and Lincoln. The cool weather is expected to persist through tonight, when additional record lows may be tied or set. After that, a gradual warming trend is anticipated next week.