This information comes from Jon at DuPage Democrats HQ, who in turn got it from the election committers. As of closing on January 21, the following numbers of early voting ballots have been cast:
Democratic - 2661
Republican - 2000
Nonpartisan - 33
Green - 6
There are, of course, a number of possible explanations for this. Maybe Democrats are more likely to vote early. Maybe Republicans are voting absentee, or maybe a substantial number are crossing over because they don't like their party's Presidential choices this year. But it's hard to look at these numbers and not be optimistic about our chances for turning DuPage blue in the fall.