Chicago weather: Warm, muggy air brings increasing thunderstorm threat

CHICAGO - This is one of the warmest, if not the warmest overnight periods of the year so far. Temperatures are in the low 70s right now across most of our viewing area. That is not surprising since we tied for the warmest temperature of the year yesterday when O’Hare hit 87°.

Today the weather turns noticeably more humid and that will fuel a thunderstorm threat starting later this morning and continuing off and on through tomorrow morning.

The risk of severe thunderstorms, especially late this afternoon and tonight, has increased. The storm prediction center forecasters have now placed much of our viewing area in a level two "slight" risk. As is often the case, the intensity of the late-day storms will rely to some degree on how much and how long the morning thunderstorms continue.

Tonight, showers and thunderstorms are likely, some of which will continue through early tomorrow morning. Highs today may actually struggle to hit 80° due to the prevalence of cloud cover and occasional rain.

What's next:

During the day tomorrow, while a shower cannot be ruled out, it appears much of the day will be rain-free, and any impact from rainfall should be brief. High temperatures will likely be warmer, getting back into the mid 80s.

Sunday still looks like a chiefly dry day, but showers are possible at times, especially in some of our southern and western counties. Highs will be in the upper 70s.

The area-wide threat of rainfall goes up again Monday and Tuesday with scattered showers and thunderstorms. Highs will be around 80 on Monday, then well into the 80s Tuesday.

Toward the middle and end of next week we will dry out and it looks hot. Our first 90s of the year may arrive as soon as Wednesday.

As for the much-ballyhooed possibility of seeing the northern lights, that did not happen. The coronal mass ejection arrived weaker and later than expected — shortly after midnight our time, and did not trigger a massive geomagnetic storm.