Warm front will dictate Tuesday's severe potential across northern Illinois

Warm Monday:

Before we break down Tuesday's severe potential, today offers a perfect opportunity to soak up the nice conditions outdoors or double-check that your severe weather plan is ready to go.

Record warmth is on the table as highs will peak around the 70° mark. Sun-filled skies will dominate from start to finish, and an organized southwesterly breeze will play a big role into pushing those temperatures well above-average. 

Altogether, it will be a warm up that will make it feel more like May than March. As we head into this evening, winds will gradually ease and skies will remain clear. With a warm front advancing northward overnight, those calmer conditions could promote moisture buildup near the surface. The result may be areas of dense fog developing potentially ahead of Tuesday's morning commute. 

Tuesday's Severe Potential:

Little has changed since Sunday regarding Tuesday's severe outlook. The Storm Prediction Center has kept most of the region under a level 2 Slight Risk, while  areas along and south of Interstate 88 under a level 3 enhanced risk for severe weather. 

    

Tuesday's severe weather potential will largely hinge on where the warm front ultimately sets up. So far, forecast models continue to keep the boundary south of Interstate 88, closer to Interstate 80.

Keeping the richer moisture and stronger atmospheric energy south of the area would shift the higher severe threat into central Illinois while lowering it locally. Even so, storms that get this far north will be capable of producing hail and flash flooding. 

However, IF the warm front pushes further north than currently expected, the severe threat would increase across the region - opening the door for all severe hazards, including the potential for tornadoes. 

Our in-house model continues to show a mostly dry day on Tuesday aside from an isolated sprinkle. The better chance holds off until Tuesday evening into Tuesday night as the surface low and warm front push across the state of Illinois. Again, the extent of tomorrow's threat will depend on the placement of the warm front so be sure to stay up-to-date on the forecast over the next 24 hours!

Severe weather risk for Northern Illinois on Tuesday

 After a sunny and mild Sunday, temperatures will take another jump in the upward direction for Monday, as afternoon highs push near 70 degrees for some! Record warmth is possible, given Rockford's standing record for Monday is 68° set in 2021.

It will be another mild day for most on Tuesday, but there will be big changes on the way. A warm front will set up near Northern Illinois, which could be the focal point for severe thunderstorms, including tornadoes Tuesday afternoon and evening. Very moist and unstable air will be South of the front, with dew point temperatures above 60°. North of that front, much drier and stable air will be found.

That axis of moisture also sets up where the best instability, or storm energy, will be for severe weather will be. The highest instability will also be found across Central Illinois where the abundant low-level moisture is found. Another ingredient for severe weather is wind shear, particularly in the lowest levels to fuel a tornado risk. That will be centered nearest the warm front, likely stalling out near or just South of I-80. Storms that form North of the front will become elevated, limiting tornado risk but enhancing large hail and flooding concerns.

As of now, the primary threat for tornadic storms on Tuesday will be centered near and South of the front, which looks to set up near or just South of I-80. North of the front, severe weather is still possible, but the main threats there will be damaging hail and flash flooding. The latest severe weather outlook as of Sunday afternoon shows the Level 3/5 Enhanced Risk across much of Central Illinois where the better ingredients will be found, including the warm front itself. The Level 2/5 Slight Risk extends about to the IL/WI state line, primarily highlighting the concern for large hail. Further updates on this outlook and the forecast will come, so stay tuned and remain weather aware this week!

Spring like conditions return for the beginning of the week

 

Following a brief cooldown Saturday thanks to an early morning cold front we can now look forward to spring like conditions ahead! Over the next few days temperatures will consistently be in 60's while both sunshine and thunderstorm chances return.

For both today and tomorrow, we'll see plenty of sunshine through the afternoon. Temperatures will slowly recover this afternoon into the 60's, however a few upper-level clouds may keep us slightly cooler compared to tomorrow. More sunshine will be likely heading into Monday combined with a continued southwesterly wind which will push our temperatures closer to 70°. 

The warm trend may continue into Tuesday, however this may change as our next upper-level system approaches. A low-pressure system is expected to develop to our west on Tuesday which will send a warm front into portions of Northern Illinois which may bring both warmer temperatures and the possibility of thunderstorms.

Depending on where this front sets up, strong to severe thunderstorms will be possible on the warm (south) side of the front. As of now we look to stay just north of the front, however due to the uncertainty so far, the Storm Prediction Center has outlined most of the region in a 2/5 slight risk. Make sure to stay updated on the forecast Tuesday as this is a constantly changing system!

 

Feeling like spring as we "spring forward" into Daylight Saving time

 Much of the Stateline saw between 0.75-1.25" of rain Friday through Saturday morning. Rockford's tally of 1.38" not only more than doubles the year-to-date total, but it is also more precipitation than we have seen since late December, when 0.89" came down on the 28th! We are still nearly 1.5" behind on the yearly total compared to average, so we still have some ground to make up!

Clouds remained in place, aiding to the darker sky much quicker Saturday evening. But Sunday evening will be bright and sunny much longer! We spring forward into Daylight Saving time at 2AM tonight, pushing sunrise and sunset times forward an hour as well. Sunrise today was 6:22PM, and it will be 7:20AM tomorrow. Sunset tomorrow will be nearly 7PM!

It will also feel much more like spring than Saturday did, with the return of sunshine and high temperatures near/above 60 for the next few days! This comes with sunshine and a breezy Southwest wind Sunday and Monday, but a chance for rain and storms Tuesday. Monday's high of 68 would tie the record set in 2021.

Tuesday's weather system will be an expansive and moisture-filled one with some abundant rainfall totals possible. A warm front will stall out across Northern Illinois, similar to Friday's setup. Severe storms may be possible South of that front, with some localized flooding concerns with the heavy rain along the front. On the tail end of the system, some snowflakes may try to mix in as temperatures may struggle to reach the 40s Wednesday.

Brief cooldown Saturday followed by recovering temperatures

 

It was certainly an active afternoon and evening last night as multiple rounds of showers and thunderstorms moved through the region. Although we experienced some pretty loud thunderstorms, our severe weather never materialized. However, for other areas across the Great Lakes and Plains multiple instances of severe weather reported. The strongest of which occurred in Southwestern Michigan as multiple strong tornadoes impacted multiple communities yesterday afternoon.

As this system continues to pass to our east today we'll see temperatures drop across the region as a cold front passes through this morning. At 5:15 am we're currently sitting in the upper 50's with the cooldown expected to begin soon, but through the morning we should achieve our high temperature in the mid 50's as this front approaches. As this front moves in a few isolated showers will still be possible, however the biggest impact we'll feel from this front will be gusty winds behind it along with temperatures gradually dropping through the afternoon.

As winds pickup today they will be orientated out of the northwest keeping some chill in the air. Into the evening though winds will gradually shift out of the southwest which will continue through the next two days. This will quickly warm us up back into the 60's tomorrow and possibly even make a run at 70° Monday!
 

 

Strong to severe storms possible Friday night

 1:45AM: Steady showers continue to push across the Stateline, but wind gusts have come down a bit. A few spots may only see the gusty showers produce winds only up to 40 mph, remaining below severe limits.

12:40AM: Though it may not look all that impressive, the showers in Northwestern Illinois have been able to tap into stronger winds above the surface, producing wind gusts of 40-50 mph in some spots. While not severe, gusty winds may accompany the showers and storms overnight.

11:15PM RADAR: The two areas of storms are moving into Southern Wisconsin and Western Illinois respectively tonight, producing heavy rain and frequent lightning. Storms are sub-severe right now. Strongest storms may be able to produce a few strong gusts (up to 50 mph) from time to time as they move to the Northeast at around 50-60 mph. ETA for Southern storms to reach Rockford at current pace: about 1-1:30AM.

9:30PM UPDATE: We are watching two main areas of storms late this evening. The first in Iowa should push North of us into Central Wisconsin overnight. The 2nd round in Northern Missouri will move our way, likely after 12AM now. The later timeline of storms will aid in a weakening trend, limiting the potential severe risk locally. While we are not fully out of the woods, the chance for a severe storm with 60+ mph winds is diminishing. Showers will linger into the morning, but we will dry out by mid-day with temperatures falling to the 40s by the afternoon.

6:30PM RADAR: All remains mostly quiet across the Stateline, but the next window of storms is beginning to take shape across Missouri and Iowa. In the wake of the storms Friday morning, the atmosphere is a little more stable locally. This has kept us drier, while the main axis of storms develops South and East of us. Now through 10PM will continue the lull in precipitation, with only a small chance for an isolated storm.

An isolated cell may try to bubble up locally before 10PM, but the main window arrives between 10PM-2AM. Damaging winds and heavy rain will be the main threats, but a brief spin-up tornado could be possible as well.

The cluster or broken line of storms will enter Northwestern Illinois after 10-11PM, then center themselves along the I-39 corridor near or after 12AM. By 2-3AM, the strongest of the activity will have pushed off to the East, but steady showers or a few rumbles of thunder remain possible through 2-3AM. Be sure to have a way to receive warnings and make sure those warnings will wake you up since the storms will be coming in late tonight!

Friday's severe weather threat across northern Illinois

Latest Severe Outlook:

The severe weather outlook saw little to no change overnight as the Storm Prediction Center maintained a level 2 of 5 Slight Risk for the area. 

 

 

 

Timing Out the Storms:

Now, today's severe threat is broken into three distinct periods: a morning threat, a possible afternoon threat, and then an overnight threat. 

Morning (6AM-10AM: This will include a batch of widespread rain and isolated non-severe storms. If any storm were to become severe, it would be for hail as these will be elevated in nature.  

Afternoon (12PM-6PM): There will be a few lingering storms behind the stuff that passes through during the morning. However, we have a warm front hovering around northern Illinois, northern Indiana, and southwestern Michigan. Any storm that interacts with this warm front will quickly go severe, posing a threat for all severe hazards. The odds of that are low but still something to monitor. 

  

Overnight (9PM-6AM):  

Thunderstorms developing along the cold front will move into the Stateline closer to the midnight hour, with chances lingering into early Saturday. These will primarily pose a damaging wind threat, but with plenty of spin in the atmosphere still in place, an isolated tornado or two cannot be ruled out. Again, be sure to have many ways to receive severe watches and warnings from start to finish today.