Heavy rain, severe storms possible across northern Illinois today

Latest on Severe Potential:

Uncertainty #1 with today's severe weather threat is already becoming apparent this morning. A large area of showers and thunderstorms is pushing into portions of eastern Iowa and southwest Wisconsin. 

How long this activity holds together - and how the atmosphere recovers behind it - will play a major role in the Stateline's severe weather potential later today. IF storms linger, they could limit instability, and the added cloud cover and rain may slow the northward push of the warm front. This could ultimately temper with the strength and coverage of severe storms this afternoon and evening. With that being said, today will be a "play it by ear" kind of day. Meaning, we have to monitor and see how things go as the day progresses. 

Heavy downpours is certainly on the table, especially with the batch of storms expected to move through this morning. IF the warm front is able to lift north into the I-88 corridor, all severe weather hazards, including a few tornadoes, would become possible, especially along and south of the front where the ingredients for severe weather is much higher. Even areas north of the warm front could still see severe weather, though the primary threat would lean more towards damaging straight-line winds.   

In the latest outlook, the Storm Prediction Center left much of the region under a level 2 of 5 Slight risk for scattered severe storms with locations along and south of I-88 under a level 3 enhanced risk. Further south, a level 4 of 5 Moderate risk remains in place for those across central Illinois and eastern Indiana. 

  

MyStateline+ App: 

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Cool Thursday:

Behind today's frontal passage, conditions become less active but cooler for Thursday. With a steady west-northwest breeze in place, afternoon highs will be limited to the low 70s once again. 

 

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!