Uncertainty still surrounds Wednesday’s severe threat across northern Illinois

3 Things to Watch:

We've got three things to watch in the forecast over the next few days, and each brings a different feel across northern Illinois. 

First up, keep an eye out this morning for a passing shower or storm- nothing widespread, but enough to wear you may run into a few raindrops during the morning commute. Tomorrow, the focus will shift to a better chance for heavier rain and storms as more moisture and energy move in. Severe weather potential locally will all depend on where certain boundaries set up. Then by Thursday, we flip the script entirely, cooler air, a steady breeze, and highs falling back close to 70-degrees.  

Today's Potential:

We'll actually miss out on any severe threat this morning as the main area of low pressure tracks to our north, keeping the stronger dynamics with the associated cold front displaced away from us. 

The Storm Prediction Center instead has a better risk for severe weather focused to the east and south of the Chicago metro, where a level 1 of 5 marginal risk is in place. In those areas, a few storms may be able to produce damaging winds and with extra spin in the atmosphere, a tornado or two cannot be ruled out. High temperatures locally will be very similar to the past few days, landing in the low 70s under partly cloudy and breezy conditions. 

Wednesday's Severe:

As we head into Wednesday, we'll be watching the potential for pockets of heavy rain and even a few isolated strong thunderstorms, especially during the mid to late morning hours. 

That early activity will play a role into how things will evolve later in the day, along with where a warm front and any outflow boundaries set up. Right now, most of guidance keep that warm front south of I-88, even south of I-80, which would limit the higher-end severe threat locally. However, if - and it's a big if - if that boundary were to lift north closer to the Illinois/Wisconsin border, that would raise the potential for all severe hazard, including damaging winds, hail, and even a strong tornado or two for areas like Rockford, Belvidere, and Freeport.  

At this point, that scenario appears to be on a lower-end possibility, but it's definitely something to keep a close eye on. For those uncertainties, the Storm Prediction Center has left much of the Stateline under a level 2 of 5 Slight Risk for scattered strong to severe thunderstorms while also upgrading portions of central Illinois and northwest Indiana to a level 4 of 5 moderate risk for severe weather. 
 

 

Cooler pattern remains, few storm chances ahead

 Much of the week ahead will be characterized by cooler, more refreshing weather. Heat and humidity are a combination not seen in the immediate forecast, keeping afternoon highs in the 70s for the next several days. Overnights will be downright refreshing, with most low temperatures in the mid 50s or cooler!

But that pattern does not come without rain and storm chances. Our first potential arrives with a quick-moving wave to the North early in the day Tuesday. This will produce some isolated to widely scattered showers and a few thunderstorms. Our severe weather looks very limited locally, but a storm or two may perk up and produce some strong winds or large hail across far Eastern Illinois into Indiana. The Storm Prediction Center has a Level 1/5 Marginal risk in place for areas South and East of the Stateline. Much of the day will be dry locally over toward Northern Illinois.

A more potent and dynamic system will arrive Wednesday. This storm threat will be much broader with better ingredients for severe weather across much of the mid-Mississippi Valley into the Great Lakes. Multiple waves of showers and storms will be possible, with some storms strong to severe.

The highest confidence of severe weather looks to be centered South of Northern Illinois with limited moisture and instability this far North. Dynamic systems like this have a tendency to make up for limited ingredients, so a few severe storms may still be possible locally. Exact timing will depend on the track of our surface low pressure. But for now, keep tuned as the forecast will likely evolve as we get closer to the event!

Rockford Ironman race weather forecast

 Radar may look a little daunting around daybreak Sunday with some isolated to scattered showers before 5-6AM. But that rain will clear before too long, exiting the area by 6-7AM. That will leave far less cloud cover and a good bit of sunshine once the sun rises.

Rockford's Ironman 70.3 race will begin at 7AM Sunday with temperatures in the low 60s and they will only warm into the low 70s. Humidity will be trending down through the day, with dew points falling to the 40s. The only minor impact from ideal race conditions will be a stout Northwest wind, gusting near 30 mph at times. Good luck to all the racers!

Breezy Saturday with scattered thunderstorms

 After a pleasant and comfortable Friday, some scattered thunderstorms may return Saturday. Winds will gradually turn to come back out of the Southwest for Saturday, with some gusts pushing 25-30 mph at times.

That Southwest direction will draw in moisture return, with dew points rising back through the 60s. That increase in moisture will be met by an incoming cold front, producing some scattered showers and a few thunderstorms. We may end up dry through mid-day, but chances for rain will creep up through the afternoon.

A few of these storms may be able to perk up and produce gusty winds and small hail. While the storms will not be very widespread, any storms that track over recently rain-soaked locations may pose a slim risk for some flash flooding. Any risk for strong storms will decrease after 10-11PM. A few showers may linger into the early half of the night, but in lesser coverage. Conditions will dry out by daybreak Sunday morning.

A few of the storms Saturday afternoon and evening may be able to reach severe limits. Much of the Stateline is under a Level 1/5 Marginal risk, indicating only a few isolated storms may reach severe limits. Southwestern parts of the Stateline, including Savanna and Sterling, are under a Level 2/5 Slight risk with slightly higher confidence on storm coverage. Our threats will only be with wind and hail, tornadoes are not a concern locally. The environment is not nearly as volatile as it was Wednesday or Thursday.

Pleasant Friday ahead, few storms Saturday

Beautiful Friday:

Today for sure will have a noticeably different feel thanks to the cold front from Thursday. Temperatures this morning are running about 5 to 15 degree cooler, setting the stage for a comfortable, and more seasonable afternoon. 

  

With plenty of sunshine and a steady westerly breeze, highs will hover around the 80°mark, making for a refreshing end to the work week. Winds will ease up this evening, setting the stage for a quiet and pleasant night. Skies will turn partly cloudy, with overnight lows dipping to around 60 degrees.

  

Weekend Outlook:

Clouds will increase Saturday as a weak cold front approaches the area. Along with it, a few ingredients come together to support an isolated strong to severe storm or two - main threats looking to be damaging winds and possible some large hail. Once the front is through, a much cooler air mass settles in for Sunday. Afternoon highs will only reach the low 70s, offering a refreshing break from the summer heat. 

Another widespread risk for severe weather likely Thursday

 Following Wednesday's storms, Thursday will bring another risk for severe weather across the Stateline and the Midwest region. The latest outlook from the Storm Prediction Center showcases a large Level 3/5 Enhanced risk for severe weather stretching from Iowa/Missouri up through mid-Michigan. Locally, all hazards of severe weather will be possible, including a few tornadoes. The overall timing of this system could be a bit earlier than Wednesday's, with storms arriving as early as 11AM.

The morning will start out mild and humid with maybe even some fog. Temperatures will rise very quickly into the mid-80s by late morning. The initial wave of storms will be approaching from the West as early as 11AM-12PM, stemming from storms that will first develop in Nebraska overnight. Similar to Wednesday, the storms will likely pose a risk for damaging wind gusts of 60+ mph and very heavy rainfall.

Additional storms will fill in through the afternoon. Scattered storms will form clusters or bow echo shapes, each posing risks for damaging wind gusts and heavy rain. As stronger wind shear (spin) builds in through the afternoon, the tornado threat may increase a bit as well, especially if cells remain individual and not clustered together.

Severe storms will slowly push across the area through the afternoon, finally exiting East after 7-8PM. The slower movement of storms will allow for some very heavy rainfall, as some locations may be able to see a couple inches of rain or more through the course of the day.

Damaging wind and heavy rainfall remain the primary threats with our storms Thursday, but there is a heightened risk for tornadoes and hail compared to Wednesday's storms. Embedded QLCS spin up tornadoes are possible within the line, which are generally shorter-lived and weaker tornadoes compared to super-cellular tornadoes. But there is a good likelihood that we will see severe storms mid-day through at least the afternoon. Remain weather aware and keep up to date on the forecast!

Northern Illinois to see back-to-back heightened severe risks

Wednesday's Severe:

Hot and humid conditions will stick around today, setting the stage for multiple rounds of storms. We'll be watching an initial wave develop early this afternoon, followed by a secondary round later this evening into the early stages of tonight. 

The Storm Prediction Center overnight expanded the Level 3 of 5 Enhanced risk for severe storms to now include the entire area Damaging winds will serve as the primary concern. While the overall tornado threat is lower locally, a brief, isolated tornado or two cannot be ruled out - though the better chances for that remain to our north and west across eastern Iowa and southwest Wisconsin. Skies will begin to clear a bit overnight, but breezy conditions linger. With this wind remaining warm out of the south and southwest, temperatures won't fall much, landing near the 70-degree mark by Thursday morning. 

Thursday's Severe:

Moving right along into Thursday, the severe weather threat ramps up even further. The strongest impacts are expected to be centered right over the Stateline as a surface low lifts to our northwest, placing us firmly within the unstable warm sector. 

This setup will support the chance for multiple rounds of strong to severe storms as the approaching cold front pushes through. All severe hazards will be on the table, including damaging winds, large hail, and even the potential for a strong tornado or two. Similar to today, the Storm Prediction Center has the area under a level  3 of 5 enhance risk, signaling that numerous severe storms are possible. 

Mystateline+ App:

With multiple rounds of strong storms expected, it's essentially important to have more than one way to receive severe watches and warnings. Make sure you have the MyStateline+ App downloaded. This is where you can get the latest updates and live coverage from the First Warn Weather Team.