Radar Image above from July 12, 2014 at 8:25 AM. Image from College of DuPage.
After a very wet and stormy start to the summer, the month of July featured dry and cool weather for much of the Mid-West and Ohio Valley. The cool and dry conditions were caused by a succession of upper level troughs that dove in from the northwest. These troughs brought in unseasonably cool, dry air that forced most storm systems south of the area. In addition to the lack of rainfall, it is also important to note that July temperatures averaged well below normal from Chicago to Indianapolis.
For Chicago, the first week in July seemed very reminiscent of June with a period of active and wet weather. In fact, close to 70% of the total monthly rainfall at O’Hare fell in the first 8 days of the month. The rainfall was associated with a stalled frontal boundary that produced widespread showers and thunderstorms. After a few warm and quiet days from July 8-11th, a heavy round of thunderstorms pushed through the area July 12th, bringing some rainfall and lots of lightning.
After the round of thunderstorms on the 12th, only 0.30” of rain fell for the rest of the month. The hottest stretch of July occurred on the 21st and 22nd, where O’Hare reached 90 degrees on the later of the two days. This was the only 90 degree day that O’Hare observed all month. That is pretty astounding when you realize that in July of 2012, Chicago saw 18 days with temperatures above 90! After this brief “heat-wave” temperatures fell back into the mid 70s for a few days. The rest of the month remained pretty quiet, with no precipitation and temperatures near average.
Farther south and east towards Indianapolis, July of 2014 was the coolest on record! The average temperature for the month was 70.1°F, which is 5.3°F below average. Amazingly, Indianapolis did not have a single day above 90 degrees. For comparison, July of 2012 featured an amazing 28 days above 90 degrees! The average July temperature for 2012 was nearly 14 degrees warmer than July of 2014. While the month was cool, it was also fairly dry as Indianapolis International Airport only received 3.10” of rain which is 1.45” below normal. The month did not lack in severe weather, as multiple rounds of strong thunderstorms would rumble through central Indianapolis.
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The first round of storms impacted the area on July 1st, as a line of severe thunderstorms produced a 71 mph wind gust at Indianapolis International. Additional rounds of thunderstorms moved through the region July 7-8th,12-14th, 23rd, and 26th. Some of these storms produced locally strong winds and torrential downpours. The storms on July 23rd produced a widespread 1-3 inches of rain across the Indianapolis area which quickly led to some poor drainage and street flooding.
