Strong to Severe Potential Today, Excessive Heat to Follow

Mid-Day Storms:

There's plenty of headlines to discuss in the days leading up to father's day weekend, beginning with today's severe storm potential.

Overnight, the Storm Prediction Center left the Stateline as a whole under a Slight Risk (level 2 of 5) for severe weather. Over the past 24 to 48 hours, forecast models have been hinting at a strong line of storms, or something we call a Mesoscale Convective System (M.C.S, sliding into the Midwest and Great Lakes during the mid-day hours. The biggest uncertainty however has been the exact placement or where these storms will set up. As of this morning, our complex of thunderstorms is gliding across the Upper Midwest section of the United States. With time, this complex is forecast to take a right turn as it moves over a ridge of high pressure, drifting more to the southeast. 

Timing & Threats:

Now, how far north this complex tracks after it makes that "right turn" will determine the magnitude of the storm threat locally. For instance, if this storm complex tracks through central Wisconsin, that would less our chance here in northern Illinois for severe weather. 

But, if it were to track through southern Wisconsin, then our chances would increase. Current thinking suggests that areas along and north of highway 20 will have the greatest threat for strong to severe thunderstorms, with the main time-frame being between 11AM to 3PM. Generally, the greatest threat with a storm system like this is damaging straight-line winds, with tornadoes and large hail being a secondary concern. Once the complex slides to the east of the region, a lifting warm front will then set the stage for a multi-day stretch with near record warmth and oppressive humidity.

Excessive Heat to Follow:

Beginning at noon today, Carroll and Whiteside Counties will be under a HEAT ADVISORY. It's not until noontime Tuesday the rest of the area will be placed under the same advisory. 

As a strong ridge of high pressure builds across the midsection of the United States, that heat will be pulled north, bringing high temperatures near 90 degrees Monday afternoon, with the mid/upper 90s Tuesday and Wednesday. Dew point temperatures are also expected to climb into the low to mid 70s which will push the heat index over the triple-digit mark, especially Tuesday afternoon.

Wednesday will also be hot, but drier air just above the surface may allow our dew point temperatures to drop some helping to keep the heat index down slightly from Tuesday. Overnight lows won't fall much Monday night or Tuesday night with temperatures holding in the low to mid 70s. 

That warmth won't give our bodies time to cool down from the humidity, especially if you don't have air conditioning, and could put added stress on our body as the heat and humidity continue. If you do have to be out and about for a prolonged period of time Tuesday and Wednesday, make sure to take frequent breaks in the shade and drink plenty of water. A cold front will cool our temperatures down towards the end of the week, with dry weather lasting into Father's Day weekend.