After several days of oppressive heat and humidity, the worst of the summer sizzle (for now) has finally begun to wither away. Temperatures will trend in the direction of early-July standards, however, the active weather stays put into the weekend.
4th of July weekend also features the opportunity for a few showers and thunderstorms. Forecast models continue to indicated a weak area of low pressure or an M.C.V (Mesoscale Convective Vortex) drifting into Wisconsin during the day.
Thursday marked the 4th day in a row that Rockford reached a high of 91°! During that time, peak heat indices ranged from 100-105°. The last time we saw such a streak of heat was nearly this exact time last year! Typically, average highs are around the mid-80s, so we were 7-8° above average each day!
The next few days will feature a subtle decrease in humidity and heat, but it will still feel like summer over the holiday weekend. High temperatures will likely push close to 90 again Friday, upper 80s Saturday, then low 80s Sunday. Each day will feature at least some isolated to scattered thunderstorm potential, so keep tuned to the radar if you're going to be outdoors for any of the holiday festivities!
The storms are generally moving in the east/northeast direction and are likely to impact southern Wisconsin over the next couple of hours. It is possible that a few of the storms could dip south of the state line into far northern Illinois by 5pm-7pm. If so, there would be a risk for an isolated severe storm or two through sunset.
There were a few minor adjustments made to the Extreme Heat Warning last night. The National Weather Service removed Jo-Daviess, Carroll, and Stephenson Counties from the warning as slightly lower temperatures and heat index values are expected in those areas. However, the rest of the Stateline remains under the Extreme Heat Warning until 12AM Thursday night.
As for today's forecast, a few isolated thunderstorms remain possible early this morning, but much of the day will feature partly cloudy skies. Despite the slight drop in humidity compared to the past few days, high temperatures remain the same, peaking in the low 90s for the 4th consecutive day. When combined with the lingering humidity, heat index values will approach the 100° mark and may briefly rise above it for an hour or two during peak heating hours.
Along with keeping an eye on the heat, watch for severe potential this evening into tonight. Much of that potential will depend on whether the atmosphere can recover following a round of showers and storms that pass through Wisconsin early in the day. It also will depend on if the frontal boundary responsible for redevelopment remains intact or fizzles out as it slides closer to the Illinois/Wisconsin border.
Highest severe threats will be strong winds, along with frequent lightning and heavy downpours. For that, the Storm Prediction Center has areas under a level 2 of 5 Slight Risk for scattered severe storms. They also have a level 2 of 5 Slight Risk in place for the entire Stateline area tomorrow as a secondary boundary sinks south.
For the third day in a row, afternoon temperatures have warmed into the upper 80s and low 90s, with the heat index climbing to 100 (or higher). Extreme Heat Warnings remain in place through tonight for Stephenson, Jo Daviess, Carroll counties and until Thursday night for Whiteside, Rock, Green, Walworth, Winnebago, Boone, Ogle, Lee, DeKalb, and McHenry counties.
Storms are likely to get going over the next few hours from parts of Wisconsin, back through Minnesota and Iowa. This is where the stalled cold front/stationary boundary resides. While most of those storms will remain to our north overnight, the slight shift in the upper-level ridge will set the stage for a little further southward development of any storms tonight. This could lead to an isolated storm or two moving into parts of southern Wisconsin and northern Illinois through sunrise Thursday. The main threat for any severe weather resides to our north, but a gusty storm or two may occur locally should any storms move towards the state line late tonight.
Heading into Thursday evening we'll need to keep an eye on any storm that develops locally as there could be a risk for a severe storm or two. Southern Wisconsin and some of northern Illinois are under a 'slight' risk for severe storms Thursday evening. A 'marginal' risk for an isolated severe storm is in place for Friday. Should any storm reach severe limits it would be capable of producing strong winds and hail.
Historically, the 4th of July is one of the hottest holidays of the year. It is right in the middle of summer, when our average high is in the mid-80s. Recent Independence Day holidays have been more of the same, with an average high of 88 degrees since 2020. Six of the last eight years have featured 90-degree days for the 4th!
This year will be right in line with recent years. Highs will reach the upper 80s with some humidity and isolated to scattered thunderstorm chances. Right now, our forecast high is 87 degrees!
Scattered thunderstorms will be possible from time to time, so it will be a day to watch the radar very closely. Highest coverage of rain appears to be mainly early in the day, with lower coverage toward the evening, but that is subject to change based on any lingering boundaries from previous storm complexes Friday into early Saturday morning. Stay tuned to the forecast for future updates!
There have been no changes when it comes to the heat alerts for the local area. All Stateline counties remain under an Extreme Heat Warning until 12AM Thursday night.
Another hot summer day is on tap for northern Illinois, with afternoon highs climbing back into the low 90s under a mixture of sun and clouds. A warm wind out of the southwest will continue to pull in humid air, leaving dew points temperatures in the low 70s. That added moisture will make it feel even hotter, with heat index values hovering around the triple-digit mark this afternoon.
Like you've done the past few days, be sure to take frequent breaks in the shade or A/C if you have to be outside for a prolonged period of time. Stay hydrated by drinking plenty of fluids not including alcoholic or carbonated/caffeinated beverages.
Yesterday marked just the second time this year that temperatures at the Rockford Airport climbed to 90 degrees or higher. For perspective, we typically see about four 90-degree days between May and June combined, meaning we're running behind schedule when it comes to the true summer heat. That trend is about to change, however, as a strengthening ridge of high pressure helps keep this extremely hot air mass in place for the start of July.
The National Weather Service has now upgraded the remaining counties across the Stateline to an Extreme Heat Warning, meaning all of our counties are now under the warning through 12AM Friday. The length of this warning speaks volumes about just how long this true summer heat will be, as several consecutive days of intense heat continue to place added stress on anyone spending time outdoors.
With the extended stretch of heat and humidity on the way, it will be very important to practice heat safety this weekend. Some tips include drinking plenty of water, taking many breaks in the shade and A/C, and limiting exposure to the sun. Also, look before you lock the car or house. Never leave children OR pets unattended outside or in a vehicle.
Extreme heat is expected across the Stateline over the course of the next week. Temperatures in the low-to-mid 90s will combine with high dewpoint temperatures to create potentially dangerous conditions. An EXTREME HEAT WARNING is in effect for all of our Wisconsin counties from noon today through 7p Tuesday. We also have the same warning in effect for Jo Daviess, Carroll, Stephenson and Whiteside counties from noon today through 10p Wednesday. Finally, a HEAT ADVISORY is in effect for the rest of the Stateline from noon today through 10p Wednesday.
It's been an unusually cool start to the summer season across, with comfortable air consistently winning over typical early-season heat. In fact, since May 1st, days topping out in the 70s have nearly outnumbered those reaching the 80s and 90s combined. We will likely see once last cool and comfortable before summer wakes up and brings the heat and humidity back.
Today will stay on the cool side, with afternoon highs settling into the low to mid 70s. Clouds will be around for much of the day as a weak storm system or an M.C.V slides across the southern Illinois. While most of the Stateline will stay dry, precipitation could track north enough for us to see a shower or two. Conditions remain dry overnight, with temperatures falling into the upper 50s.
After a brief warm-up into the 80s over the weekend, a surge of warm air advection combined with strengthening ridging aloft will send the 90s back right into the Stateline. In fact, high temperatures on Tuesday and Wednesday run 20 degrees warmer than what have in the forecast today. Of course, next week's southerly to southwesterly wind will send dew point temperatures into the low 70s, making it feel more oppressive across the area. This will also be the type of stretch where there's little relief at night, with overnight lows only falling into the low to mid 70s, offering minimal cooling before the next hot and humid day.
It's been an impressively comfortable second half of June across northern Illinois, with temperatures running below typical early-summer levels. We've seen a steady run of cool afternoons and low humidity, making it feel more like late spring at times than early summer. In fact, yesterday marked the 12th day this month where afternoon highs didn't even make it to the 80-degree mark.
A strengthening ridge of high pressure will the take over, helping to crank up the summer heat late this weekend into next week. So far, Rockford hasn't seen a single 90-degree day this June, but that's likely to change as we get to the end of the month.
Afternoon Highs are expected to climb into the 90s starting Tuesday, marking a noticeable shift in the pattern. And of course, with that heat will come increasing humidity, pushing heat index values into the triple-digits on multiple days next week, especially Wednesday. For those reasons, enjoy these cooler, comfortable days - and the chance to keep the A/C off while you can.
In the short-term, temperatures will remain slightly below average through the rest of the week with highs in the upper 70s. The average high this time of year should be in the low 80s. Following the passage of
High pressure remains in control today, keeping conditions across northern Illinois quiet, comfortable, and largely storm-free.
Skies will remain partly cloudy through the afternoon, helping temperatures climb into the upper 70s, right near that 80-degree mark. With point settling in the upper 50s, it'll feel similar to Monday, refreshingly less humid making for a pleasant early-summer day. Also, perfect weather for Food Truck Tuesday! Now, if we do see temperatures stay shy of the 80-degree mark, today would mark the 11th day this June with highs in the 70s, highlighting just how below-average this month has been.
Cloud cover will begin to increase overnight into the early stages of Wednesday as an occluded low and a warm front draw closer to the Stateline. As we move into the warm sector by Wednesday afternoon, there may be enough instability in place to support an isolated threat for strong to severe storms during the late afternoon and evening hours.
According to the National Weather Service Chicago the high of 68 degrees was the coolest first day of summer since June 21, 2018, when Rockford reached a high of only 65 degrees (records dating back to 1905)! That date also tied with June 22nd, 1906, as the coolest observed first day of summer.
Dating back to 1905, there have only been 8 summer solstice days with a high temperature in the 60s in Rockford, including yesterday afternoon. Thankfully, our temperatures are looking up (and that started with Monday). Highs the rest of the week will be in the 70s, although still just a bit below the average high of the low 80s. Soon, though, the summer heat and humidity will return. I'll have more on that in a later post.
It's hard to believe that just last Friday, we were discussing about how Illinois had already surged past 160 tornado reports this year - a number that, on its own, already signaled an incredibly active season. Fast forward just a few days, and the atmosphere has only added to that mind-boggling total.
After yesterday's tornado outbreak in central and southern Illinois, the statewide count is even higher, now sitting just a handful of reports shy of 200.
What's even more staggering is how Illinois stacks up against the traditional severe weather hotspots. If you combine the total number of tornado reports from states like Nebraska, Kansas, Oklahoma, and Texas - they only edge out Illinois by four reports.
Thankfully, Illinois finally gets a chance to catch its breath over the next few days. After an intense stretch of severe weather, the threat or highest potential will shift out of the region, moving into the Mid-Atlantic, as well as back west along the Rockies.
Steady showers will clear out Sunday night, leaving us drier into Monday morning. While an isolated sprinkle cannot be completely ruled out Monday or Tuesday, most will remain dry as high temperatures reach the mid/upper 70s. Very similar temperatures are forecast through this entire week, with afternoon highs ranging between 76-77 every day through Saturday. Scattered thunderstorms will be possible Wednesday, but much of the remainder of the week looks drier.
However, the cool and comfortable pattern we have been in will not last much longer. There is an increasingly strong signal to see the summer-like pattern return beginning late next weekend. The long-term outlooks from the Climate Prediction Center support this, giving the Stateline a 50-60% chance to see above average temperatures between June 29th-July 5th. That would indicate more 80s and possible 90s on the way, more like what we come to expect in July. The warm-up also looks to arrive with much more humidity and storm chances as well. So, enjoy the 70s while they last!
Unfortunately, the forecast for Sunday is not nearly as pleasant as Saturday was with steady rain arriving by early afternoon. Rain will begin as early as 9-10AM for some of our Southwestern Counties and continue to spread Northeast through early afternoon. Southeast Wisconsin may not see rain start until after 12PM.
Steadier rain will be likely for everyone by early afternoon, with hourly rainfall rates near 0.25"/hr at times. A few rumbles of thunder will be possible as well, particularly in Southern portions of the area. While the heaviest rain will exit after 6PM, pockets of light to steady rain will persist into the night.
Temperatures will reach into the low 70s before/as rain starts but drop through the afternoon into the mid-60s as rain picks up in intensity. Winds will also pick up through the afternoon, gusting near 25-30 mph at times from the East.
Rainfall will add up much quicker for some compared to others. South of I-88 will see the highest rainfall totals, with some picking up between 1.0-1.5" or more. Between about I-88 and the IL/WI state line, you can expect between 0.5-1.0" of rain. Far NW Illinois and Southern Wisconsin may only see 0.25-0.5" of rain.
