Heat, humidity cranks up into next week

Monday and Tuesday were both extremely nice days to keep the A/C off and have the windows open. That all changes over the next week as multiple waves of summer-like air filter eastward.

One of those days being today as plenty of sunshine, a warm southwest breeze, and a dry atmosphere assist in bringing highs to the 90° mark.  Now, Rockford has only observed 1 day with a high at or above 90° this year and that was back on May 21st.  Thankfully, today's 90° heat won't feel as summer-like as those in the near-future as dew point temperatures remain in the 50s. Moisture streaming out ahead of the thunderstorms to our northwest will allow clouds to increase overnight. This may also bring the chance for a few storms before daybreak Thursday, especially north of highway 20.

The better chance for thunderstorms, especially for areas along and south of the IL/WI border, arrives with a cold front Thursday. 

Overnight, the Storm Prediction Center left most of northern Illinois under a level 1 Marginal Risk. Those south of I-88 have a slightly higher chance for severe potential, hence the level 2 Slight Risk. Storms late Thursday afternoon and evening will pose a risk for strong winds, large hail, and heavy downpours.

Something to keep in mind if you plan to head to the first day of Old Settlers Days! Storm threat should quickly simmer down into Friday morning, with skies turning partly cloudy. Behind the frontal passage, winds will switch back to the northwest, leaving high temperatures in the low 80s. The same could be said for Saturday afternoon. 

By Father's Day, a "ring of fire" pattern will set up in the upper-levels, allowing an oppressively hot and summer-like airmass to settle in. Temperatures from Father's Day to the middle of next week look to top out in the low 90s. Overnight lows will trend upward, landing only in the low 70s Sunday night Monday night. Along for the ride will come a daily chance for rain and pulse-like thunderstorms, especially during the afternoon.