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.
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.
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!
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.
Written By: First Warn Weather Intern Patrick Murray
After what was the second driest May on record for the Rockford Airport, we’re entering a very active stretch of weather across the Stateline region over the course of the next few days. Multiple chances of showers and thunderstorms will make their way into the area, and severe weather is expected at times.
We started this morning with mostly cloudy skies, but have since cleared out a bit allowing for our temps to soar into the 80s. With dewpoints in the upper 60s/lower 70s, it has certainly felt more like mid-August rather than early June.
This afternoon, as yet another Mesoscale Convective Vortex (MCV) spins away to our south, an isolated thunderstorm or two will be possible. These storms could contain frequent lightning, very heavy rain and perhaps a severe wind gust or two. The Storm Prediction Center (SPC) has the entire Stateline under a MARGINAL (level 1/5) risk for severe thunderstorms.
TONIGHT:
For tonight, a surface warm front is expected to push north through the area overnight tonight, and with that, it will bring a chance for isolated to widely scattered showers and thunderstorms. These likely wouldn’t be anything to worry about, just seeing mainly heavier downpours with the strongest thunderstorm.
WEDNESDAY:
Then, our attention quickly turns to tomorrow, where more widespread, potentially significant severe weather appears possible, if not likely. A broad area of low pressure has developed across the northern Plains. This storm system will begin to eject northeast, bringing multiple rounds of thunderstorms to the Stateline. The first round of storms could arrive as early as late Wednesday morning into early Wednesday afternoon. The High Resolution Rapid Refresh (HRRR) model shows a potent Mesoscale Convective System (MCS) moving through central Wisconsin early tomorrow morning. The concern with these storms is they may leave an outflow boundary or two draped across the Stateline area. These boundaries help to enhance the severe weather potential. The HRRR shows strong thunderstorms firing across far eastern Iowa by late morning and moving into northern Illinois/southern Wisconsin by early afternoon. The big takeaway is that these storms MAY fire. There is always the chance that these boundaries don’t set up where they are forecasted to and we don’t see development in the early afternoon OR storms develop somewhere outside of the Stateline.
Unfortunately, that is only round one of what could be three rounds of strong to severe weather. The “main” threat for Wednesday will be in the late afternoon into the evening hours, when a more pronounced MCS moves into the area. With this, damaging wind gusts will be the main threat. However, brief spin-up tornadoes are always possible with MCS complexes.
Regardless of if severe weather occurs or not, very heavy rainfall is expected with these thunderstorms, along with frequent cloud to ground lightning.
THURSDAY:
Unfortunately, the threat doesn’t end there. Another day of severe weather is expected Thursday across the entire Stateline. Much of the day will be spent seeing partly sunny skies. This will give the atmosphere ample time to destabilize ahead of a cold front that will be moving into the Stateline Thursday afternoon into Thursday night. The HRRR indicates yet another strong MCS moving through the Stateline late Thursday morning.
We’d need to keep a close eye on this complex for the potential for significant damaging wind gusts and again, spin-up tornadoes. These storms would likely drape outflow boundaries across the Stateline again and could work to help enhance severe potential Thursday afternoon. Again, all severe hazards will be in play on Thursday.
Things quiet down Friday as the cold front pushes through the area, bringing more mild temperatures and less humidity.
The takeaways; ensure you know your severe weather plan, keep close tabs on the forecast over the course of the next few days, and have multiple ways to receive warnings. Thursdays severe potential will depend heavily on what happens Wednesday, and Wednesday’s severe potential will depend heavily on what happens tonight elsewhere.
Cloud cover will gradually give way to a partly sunny and humid afternoon across the Stateline. Dew point temperatures will be in the upper 60s, giving the air a more noticeably humid feel.
That added moisture could be enough to spark an isolated thunderstorm or two during the peak heating hours of the day. Any storm that does manage to pop-up will be brief and spotty, though could produce gusty winds at times. Overall, today's severe potential remains low, with the Storm Prediction Center placing our area under a level 1 of 5 Marginal Risk. Chances remain isolated for tonight, with overnight lows falling to 70 degrees.
Wednesday's Severe:
Looking ahead into Wednesday, the setup becomes more concerning for severe weather. A strengthening surface low lifting into Minnesota will drag a strong cold front towards the region, providing a somewhat better focus for storm development by the afternoon and evening. This morning, the Storm Prediction Center kept most of the region under a level 3 of 5 enhanced risk for severe weather.
Tornado potential looks to be greatest north and west of the area, especially across northeast Iowa, southeast Minnesota, and southwest Wisconsin - where storms have a higher chance of being discrete. Closer to home in northern Illinois and southern Wisconsin, the main threats will shift toward damaging winds along with the possibility for a few tornadoes as storms roll in Wednesday evening into Wednesday night. The evolution of today's weather will be important to watch, as it could significantly influence Wednesday's severe threat.
Thursday's Severe:
Thursday also could be a significant day across the region as the strong cold front pushes through. Again, what happens the day before will play a huge role into what happens later in the day.
There's been a mention - though confidence remains low for now, of an M.C.S, or a strong line of storms, moving through Thursday morning. That's something we'll be watching closely. However, IF that scenario does not materialize, the atmosphere could become primed for more significant severe weather later in the day, with all hazards on the table, including the potential for strong tornadoes. As always, continue to monitor the forecast, but also take time to review your severe weather plan. Make sure you have multiple ways to receive severe weather alerts and know exactly where you would go if threatening weather develops.
4:15pm Update: Widely scattered thunderstorms continue to move across northern Illinois and southern Wisconsin late Monday afternoon, all ahead of a little low-pressure system - known as an M.C.V (mesoscale convective vortex) leftover from the showers and thunderstorms Monday morning. The overall severe threat has remained pretty low with the storms so far this afternoon, but copious amounts of moisture over the region has led to heavy downpours with any thunderstorms that have developed.
The line of storms will continue to lift north into southern Wisconsin over the next 30-45 minutes, with isolated activity lasting through sunset. The humidity will remain high and temperatures warm through the night, only dropping to around 70 degrees. Light winds and plenty of moisture, combined with a stalled boundary near the state line, will lead to areas of fog and drizzle Tuesday morning.
