Heat wave set to break
By Tony Graf tgraf@stmedianetwork.com July 7, 2012 8:18PM
Ice cream vender Manuel Rodriguez, of Joliet, waits for the lights to change at Cass and Chicago with the electronic sign on the building in background reading 105 degrees in Joliet, Illinois, Friday, July 6, 2012. | Joseph P. Meier~Sun-Times Media
Updated: August 9, 2012 9:45AM
A six-day heat wave was expected to end Saturday, capping off a stretch of intense storms followed by record high temperatures in the Chicago area.
Sunday is expected to bring a break from these extreme weather conditions, with partly cloudy skies and highs in the lower and mid-80s.
Last week’s heat wave began Monday — with a high of 98 degrees Fahrenheit, almost reaching the record 99 set in 1970, according to the National Weather Service website, www.crh.noaa.gov.
Wednesday, Thursday and Friday saw highs above 100, with each day tying or breaking a record.
The July Fourth high temp of 102, at Chicago’s O’Hare International Airport, tied the old record of 102 set in 1911. Joliet had a high of 99.
Thursday had a record high temp of 103 at O’Hare, breaking the record of 102 set in 1911. Joliet had a high of 100.
And Friday had a record high of 103 at O’Hare, breaking the record of 99 set in 1988. The Joliet area had a high of 100.
On Saturday, Will County was under an excessive heat warning, with a Joliet temperature of 90 just after 5 p.m. Saturday’s high temps were as extreme as 105 at the Rockford airport.
Why the stretch of hot weather? The jet stream was moving in an area where it was delivering a lot of warm, moist air from the southwest, the National Weather Service said in an interview Saturday morning. That system seems to be moving farther to the south now, and that should bring some cooler air, the service’s Romeoville office said.
Now, a different air mass is moving in from Canada, and the Joliet area can expect some lower temperatures than those of last week, the service said.
Last week’s heat wave was preceded by three days of storms in the Chicago area. A June 29 storm caused nearly 46,000 power outages in the Joliet area. The storm felled trees and brought down power lines in Lockport and caused damage and disruption. The weather service reported wind gusts of 87 mph in Romeoville and 85 mph in Lockport.
The weather service referred to the June 29 storm as a “downburst.”
Storms continued in the Chicago metro area throughout June 30 and July 1. Those storms caused outages mostly in the north and west suburbs.
Sunday night should be mostly clear, with lows in the lower and mid-60s, according to weather service forecasts. Monday should be mostly sunny, with highs in the mid-80s. And Monday night should be mostly clear, then become partly cloudy, with lows in the lower and mid-60s.
