Warmer Conditions Prevail in Late May

After a cold start to May (see earlier post), the period between May 18 and 27 was much warmer. The statewide average temperature during this period was 3.7 degrees above normal. The earlier cold period and this later warm period will pretty much cancel out, leaving May temperatures close to normal as we near the end of the month.

The statewide rainfall for the month is at 5.48 inches, 1.71 inches above normal. While wetter than normal, this is a long ways from the record May rainfall for Illinois of 8.87 inches set in 1943.

On a personal note, I drove through Springfield on I-72 on the afternoon of May 26 when a severe thunderstorm developed over the city. According to CoCoRaHS weather observers in Springfield, rainfall reports ranged from 2.10 on the far west side to 4.60 inches in the east-central side of the city – all in less than 2 hours (see map). I drove through wind-driven rain, lightning, and pea-sized hail. The flooding along the I-72 and I-55 entrance and exit ramps was impressive but conditions were even worse in town.

Springfield, IL May 26 rainfall
Rainfall reports for Springfield, IL (Sangamon County) for the storm of May 26, 2010. The reports are made the next morning, May 27. Click to enlarge.