Increasing threat for widespread severe weather Monday in Northern Illinois

 A broad region may see a potential for severe weather on Monday, including Northern Illinois. The Storm Prediction Center has been on this threat all week, highlighting the severe weather potential since Thursday. The latest outlook as of Saturday night shows a Level 3/5 Enhanced risk for severe weather stretching from far Southwestern Wisconsin down into Northern Arkansas. For a large majority of this area, all hazards of severe weather will be possible, including a threat for tornadoes.

But there are still a number of things that need to fall into place before this severe threat develops. Seeing as we are still nearly 48 hours from the severe threat, there are some uncertainties as to how the environment will evolve. Multiple waves of storms look possible, including a morning round. But how fast that round clears will determine how much the atmosphere is able to recover before the afternoon and evening. Another thing that will impact severe potential is storm mode. If we see discrete supercells, tornado and hail potential will be higher. If storms merge into a line or cluster quickly, the wind threat would be highest with some embedded tornadoes.

Our primary severe weather timing will be from about 3-8PM, but some of the morning and afternoon storms may pose a lower risk for severe weather too. One thing is for sure, Monday looks to be another active day in Illinois with regard to severe weather. Sunday will be the days to make the severe weather plans of what you will do in case a warning is issued. Think of where you might be between 3-8PM and where you will go if you receive a warning. Be sure to stay updated on the forecast through Monday as we continue to bring you the latest!

Pleasant but cooler weekend with patchy fog possible overnight

 This weekend will be a pleasant one even if we don't quite see the 80s like we saw Thursday! Temperatures will remain above average with highs in the upper 60s and lows in the 40s.

With a bit of lingering moisture and a lighter wind, we could see some patches to areas of fog develop Friday night. Highest confidence on fog coverage would be focused along and East of I-39, but patchy fog may be possible area-wide.

Aside from that patchy fog, the weekend is uneventful and pleasant with high temperatures pushing into the upper 60s or right around 70! Both Saturday and Sunday will feature fair amounts of sunshine, leading to pleasant conditions for outdoor activities!

Monday will bring our next chance for some storms, with some potentially severe. There are still a number of things to hash out before we get there to determine timing and exact level of severe threats, but a broad region of low pressure will bring a large area of storm potential stretching from Southern Wisconsin down into Arkansas. The main questions remain with how much recovery we see after a morning round of storms, and where the placement of the most favorable environment will be. But as of now, all hazards of severe weather may be possible including tornadoes. Stay tuned for forecast updates through the weekend!

Quiet weekend ahead, then eyes on Monday’s storm potential

Cooler Friday: 

Sunshine did most of the heavy lifting Thursday, but a steady south to southwest breeze helped seal the deal. That warm, dry flow allowed temperatures to climb efficiently through the afternoon, pushing Rockford into the 80s for the 4th time this year. 

  

Temperatures won't be quite as warm moving forward as our next cold front pushes through before the midday hours. Ahead of this cold front will also be a few showers and possibly a thunderstorm or two. Chances will come to an end rather quickly, allowing clearing to gradually take place. Afternoon highs will end up roughly 10 to 12 degree cooler than Thursday, landing near the 70 degree mark. 

  

Weekend Forecast:

Looking ahead to the weekend, things shape up to be fairly quiet. Expect mainly dry conditions both days with temperatures hovering around 70 degrees. Rain chances should hold off as they will be more focused across the southern plains. Our next opportunity for rain and thunderstorms won't arrive until late Sunday night with chances stretching into Monday.  

Monday's Severe Potential:

It's this precipitation that we'll need to keep a close eye on as it may play a role in determining Monday's potential for strong to severe storms. How morning showers and storms evolve could either limit or enhance our local threat. At this point, the primary focus for stronger to severe weather sits farther south along the warm front in central and western Illinois. Severe potential will also be heightened near the surface low ax it lifts into eastern Iowa. For that, the Storm prediction Center has expanded the 30% or enhanced risk equivalent to included a majority of the Stateline. Again, something to keep an eye on over the weekend. 
 

Looking ahead to next chance for widespread storms Monday

 While Thursday night's severe weather event seems relatively isolated in nature, we could be looking at a more widespread chance for storms Monday. There are several things that forecasters look at to identify potential for severe weather. The primary ingredients include moisture, instability, lift, and wind shear.

Two ingredients will be met with a "shortwave" in the jet stream that looks to push overhead toward Monday. This will provide the lift along a surface low pressure system and the necessary wind shear to keep storms going. Broader forcing and ideal timing of storms arriving in the day will allow for a more widespread storm potential compared to Thursday night's storm potential.

The other two ingredients are related to moisture. Abundant gulf moisture will approach the area Monday, tugged Northward along that shortwave. That will allow for more widespread rain with also some heavier rain possible. Right now, the most aggressive instability, or storm energy, looks to be centered across Central Illinois. But the Northern fringes may produce severe weather locally as well. There are still several factors that will need to fall into place before this severe threat would come to fruition.

While we are still a few days out, the Storm Prediction Center has already highlighted a broad region for severe weather potential, extending up to far Southern Wisconsin with the 15% risk, which is equivalent to a Level 2/5 Slight risk when it comes to severe weather probabilities. A 30% risk extends across Southern Illinois into Missouri and areas South. That is equivalent to a Level 3/5 Enhanced risk. While we are still more than a few days out, Monday will need to be a day to watch for widespread storms and potential for severe weather!

Thunderstorms chances increase late Thursday evening, Isolated severe threat overnight

10:20PM UPDATE: A Severe Thunderstorm Warning has been issued until 11pm for far northwest Jo Daviess County. 60 mph wind gusts and penny sized hail will be possible. The storm is currently moving northeast at 50 mph.

 

ORIGINAL POST: Temperatures Thursday afternoon warmed into the upper 70s and lows across northern Illinois and southern Wisconsin, with Rockford's high reaching 81 degrees. Skies have been dry throughout the afternoon as a few showers and isolated thunderstorms have bubbled up west of the Mississippi River, and into southwest Wisconsin.

Most of the evening will feature dry skies but an isolated shower/storm can't entirely be ruled out after sunset across far northwest Illinois. The main line of storms will arrive with the cold front, set to move in overnight. The Storm Prediction Center continues to highlight southern Wisconsin and northern Illinois under a 'marginal risk' for an isolated severe storm or two tonight.

Ongoing severe weather can be seen with a line of storms stretching from southern Minnesota, down through Iowa, and into Kansas. This is where the highest risk for severe storms will be through the evening. As the line shifts east tonight, it should generally be on a weakening trend as it nears the Mississippi River. However, there could still be just enough instability to help maintain at least an isolated severe risk - mainly with strong wind gusts - through the early overnight.

It looks like the storms should be entering into northwest Illinois between 10pm and Midnight, moving east through 4am. Frequent lightning and heavy rainfall will also accompany any of the storms that move through, but thankfully our flooding threat is low. We'll continue to monitor the radar out west and as the storms approach the region later tonight. 

Warm, breezy & June‑like with storm chances to follow

Next Severe Potential:

After the active week we dealt with last week, things have been noticeably quieter. That lull won't last completely, though - a few strong storms could roll through northern Illinois late this evening into the early stages of Friday morning. The Storm Prediction Center has maintained the level 1 of 5 Marginal Risk for severe weather for the entire area, with gusty winds being the primary concern.  

Ahead of tonight's thunderstorm chances, a June-like afternoon is shaping up thanks to very dry, but breezy conditions. Winds will be out of the south-southwest, gusting up to 30 mph at times. This will help push temperatures back into the low 80s, marking Rockford's 4th 80-degree day of the year. Normally, average highs towards the final stretch of April are sitting in the low to mid 60s. 
 

Severe Potential Shifts South:

Beyond today, the focus for any severe weather shifts well to our south. Storms capable of producing strong winds and large hail will be possible across Texas, Arkansas, Louisiana, and Mississippi. 

 

  

Heading into the weekend, we'll be watching a classic dryline set up take shape over the southern plains. That isn't a term we typically use this far north when talking about severe weather. A dryline is a boundary where warm, humid air meets dry, hot air. IF a storm were to form along the dryline, supercells capable of producing all severe hazards, including strong tornadoes, will be possible.  

Monday is the day we'll need to keep a closer eye on for strong to severe storms. The Storm Prediction Center has placed the entire Stateline area under a 15% risk, which is equivalent to a level 2 of 5 Slight Risk. A higher 30% risk, or Enhanced Risk (level 3 of 5), is centered further south across eastern Missouri and southwestern Illinois. 
 

 

Warm and breezy Thursday ahead of overnight storm chance

 Thursday will bring yet another day of warmth and sunshine with high temperatures pushing this time into the low 80s. We will only start in the mid-50s with a few patches of fog across far Northeastern Illinois, but sunshine and increasing winds will quickly push the fog out and allow temperatures to begin climbing.

Afternoon wind gusts could push 25-30 mph at times out of the South-Southwest. While the strongest gusts ease after sunset, it will remain breezy into Thursday night.

A chance for storms will develop overnight into Friday morning across the Stateline. Thursday afternoon will be "capped" across the Stateline, limiting thunderstorm activity. But a line of storms will develop Thursday evening in Iowa, then push our direction late into the evening or overnight.

The late evening or overnight timing of the storms will be unfavorable for strong to severe storms, weakening them on approach. While a few isolated instances of gusty winds may be possible, the large majority, if not all, of activity will remain below severe limits.

There is a Level 1/5 Marginal Risk from the Storm Prediction Center, highlighting the very isolated risk for us locally. Stronger storms will likely develop much earlier in the day across Iowa, hence the Level 2/5 Slight Risk that direction. Any storms that produce severe weather locally will be primarily capable of gusty winds, likely under 60 mph for the large majority of them.

A few showers and rumbles of thunder will linger through Friday morning and into early afternoon but drying out for Friday evening. Most of the weekend will be dry with highs in the upper 60s to low 70s.