Chicago’s begin to rise today, then rise considerably higher Wednesday through Friday. Highs today, although warmer than Monday’s 39 degrees at O’Hare International Airport, will still be about 10 degrees below the normal high of 57 degrees. But temperatures by Friday afternoon will hit the lowers 70s, although a sharp cool-down takes place on Saturday as another chilly surge hits the city and lasts for at least a few days. Afternoon high temperatures on Sunday and Monday will be the middle 40s and nighttime lows in the upper 20s, readings more like in early or middle March. Showers and thunderstorms will accompany the return of colder air Friday and Saturday. It dries out with the arrival of colder air by late Saturday, and dry weather but chilly temperatures are forecast for Sunday and Monday.