Precipitation Distribution for July 2011  This July was the
wettest on record for Chicago (O’Hare International AP); along
with the region that encompasses Dubuque, IA to Freeport, IL. At
O’Hare, 75% of July’s rainfall occurred within a two day span
(22 July-23 July). Before those dates, the last significant
rainfall that had been recorded at O’Hare was 11 July, 2011;
when 0.39” of rainfall was recorded. By comparison, the station
at Galena, IL received 13.45” of rain in a 24 hour span on 28
July, 2011. That same mesoscale convective complex did indeed
affect areas further east, but was not as efficient upon
reaching Chicago O’Hare. The Galena area had an initial complex
come through, and the outflow boundary left from the first
complex was enough to initiate new storms. These new storms
trained over areas which had already recorded excessive
rainfall.    Surface Frontal Analysis 22 July 2011  Figure 1:
Note the orientation of the quasi-stationary front draped across
north central IL.   The start of the two d