There are plenty of headlines to discuss in the days leading up to Father’s Day weekend, starting with today’s severe storm potential. Overnight, the Storm Prediction Center placed the entire Stateline at a Slight Risk (level 2 of 5) for severe weather.
For 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 (MCS), creeping into the Midwest and Great Lakes during the midday hours. However, the biggest uncertainty has been the exact location or where these storms will settle. As of this morning, our thunderstorm complex is sliding across the upper Midwestern United States. Over time, this complex is forecast to turn to the right as it moves over a high-pressure ridge, moving further to the southeast.
Moment and threats:
Now, how far north this complex continues after making that “right turn” will determine the magnitude of the storm threat locally. For example, if this storm complex continues through central Wisconsin, that would reduce our chance here in northern Illinois for severe weather.
But if he were to track down southern Wisconsin, our chances would increase. Current thinking suggests that areas along and north of Highway 20 will have the greatest threat of strong to severe thunderstorms, with the primary time frame between 11 a.m. and 3 p.m. Overall, the greatest threat with a storm system like this is damage from straight-line winds, with tornadoes and large hail being a secondary concern. Once the complex slides east of the region, a rising warm front will set the stage for a multi-day stretch of near-record heat and oppressive humidity.
Excessive heat to follow:
Beginning at noon today, Carroll and Whiteside counties will be under a HEAT ADVISORY. It is not until noon on Tuesday that the rest of the area will be placed under the same advisory.
As a strong ridge of high pressure builds up in the midsection of the United States, that heat will shift north, causing high temperatures to approach the 90s on Monday afternoon, with the 90s middle/upper grades on Tuesday and Wednesday. Dew point temperatures are also expected to climb into the 70s, pushing the heat index above the triple-digit mark, especially Tuesday afternoon.
Wednesday will also be hot, but the drier air just above the surface may allow our dew point temperatures to drop a bit, which will help keep the heat index down slightly from Tuesday. Overnight lows won’t drop much Monday night or Tuesday night with temperatures staying in the 70s to 70s.
That heat won’t give our bodies time to cool off from the humidity, especially if you don’t have air conditioning, and could put more stress on our bodies as the heat and humidity continue. If you have to be outside for an extended period of time on Tuesdays and Wednesdays, be sure to take frequent breaks in the shade and drink plenty of water. A cold front will cool our temperatures towards the end of the week, with dry weather lasting through Father’s Day weekend.