15 Years Ago Today

The July 1995 heat wave in Chicago was on of the worst weather-related disasters in Illinois history with roughly 525 deaths over a 5-day period!  The really hot weather occurred between July 12th and 16th where temperatures rose into the upper 90s and low 100s!  The 106° set the record for the warmest July temperature since records began at Midway Airport in 1928 (Jim Angel - State Climatologist Illinois State Water Survey).   Not only were daytime temperatures hot, nighttime lows only reached the low to mid 80s both the 13th and 14th.
An upper level ridge developed over the southwestern parts of the United States earlier that week and resulted in rising temperatures through the Plains.  Over the next couple of days the ridge, with the heat, shifted eastward over the eastern half of the U.S.  The ridge, combined dew points in the upper 70s and low 80s, helped create heat index values well into the 100s! 

Another contributing factor to the heat wave was the "urban heat island" effect.  This is caused by the high number of buildings, pavement, parking lots, etc that are found in urban areas, which tend to absorb more heat during the daytime and radiate more heat at night.  This causes less cooling during the overnight keeping lows fairly high.

Thankfully our little mini heat wave will be nothing compared to this the next couple of days!