Temperatures Tuesday afternoon warmed into the mid and upper 80s, officially reaching 87 degrees in Rockford. This occurred before a line of severe thunderstorms moved through the region. As the rain moved in, temperatures dropped into the 70s only to rise back into the low 80s by the evening.
Strong southwest winds were able to push a little more moisture into northern Illinois and southern Wisconin, bringing dew point temperatures into the mid and upper 60s for a time during the afternoon. As the cold front came through the wind direction shifted from the southwest, to the west and northwest. It took a little time but the dew point temperatures have now fallen into the upper 40s and low 50s making it feel much more comfortable for tonight. So if you turned on the air conditioning during the afternoon, you can turn it back off for tonight, and leave it off for the next few days.
But the break in the heat and humidity won’t last as temperatures are expected to rise back into the mid and upper 80s Saturday, possibly remaining there into the beginning of next week. A warm front will lift north through the Stateline late Friday night and Saturday. Winds will once again increase from the southwest Saturday as the pressure gradient strengthens between a deepening low pressure system across Canada, weaker low over the central Plains and high pressure off the East Coast. The southwest wind will push temperatures into the mid and upper 80s, possibly tagging 90 degrees, by the afternoon. Dew point temperatures will also rise, but it shouldn’t be too humid for the afternoon. Despite the rise in temperatures Saturday there appears to be limited moisture in the atmosphere which will lead to a mostly dry day.
A cold front will then come through during the evening/night, passing through Sunday. Just a slight chance for a shower or storm is in the forecast during that time. The cold front will then lift north as a warm front Monday, wobbling back and forth through early next week. This will occur as high pressure builds in over the south, placing the more active portion of the jet stream overhead. Thunderstorms are also possible during that time, but trying to pinpoint them this far in advance is quite difficult. Temperatures into next week could very well remain in the mid and upper 80s through at least mid-week.