Temperatures are falling much faster than the last few nights, with overnight lows that will reach down in the low 60s. Under a lighter wind, a few patches of fog will be possible, with some pockets of locally dense fog in low-lying areas.
Tonight is just the start of a few cooler nights, with overnight lows in the upper 50s to low 60s. Much more comfortable air will be with us through the holiday weekend, as dew points remain below the 70-degree mark until Tuesday. Patches of fog will be possible at least Saturday and Sunday nights with high pressure and a lighter wind overhead.
After Friday recorded a 4th straight day in the 90s to kick off September, the holiday weekend will not be quite as hot. The main reason for this will be the decreased humidity. High pressure will spread across the Great Lakes region, working to push the humid air mass back West again for a few days. This will send dew points down into the 60s, a much more comfortable feel than the mid and upper 70s from earlier in the week.
That will result in a much more pleasant, but still warm, forecast for this Labor Day weekend. Air temperatures may still push into the mid-80s Saturday, but lower 80s on the way for Sunday and Monday. Overnights are even more reflective of the less humid air, with lows in the 60s most nights! The lighter wind amid high pressure may result in a few nights of patchy fog, though. Lacking more sufficient moisture and upper-level dynamics, we will remain dry through at least Monday.
[11PM] The bulk of our thunderstorms have now pushed well off to the East, resulting in drier conditions locally. While an isolated shower or storm remains possible into the night, most will stay dry. Humidity does not go anywhere, with temperatures only dropping into the low 70s. Patches of fog may be possible early Saturday morning.
[8:55PM] The storm has lost a bit of its strength but may still produce a quick burst of heavy rain and a strike or two of lightning as it moves overhead. Motion is still to the Southeast at around 30 mph.
[8:35PM] There have been a few more lightning strikes on this cell near Durand/Pecatonica in just the last few minutes. Storm is moving Southeast at around 20-30 mph, which could put it near the NW side of Rockford around 9PM if it holds together.
[8:30PM] A couple of isolated showers have developed near the Stateline. One moving into Northern Winnebago County that recently produced a lightning strike near Durand, and another in Western McHenry County. Both cells are moving Southeast at 20-30 mph.
[7PM] Thunderstorms have struggled to maintain themselves into the Stateline, with only a few stray showers surviving into Jo Daviess County. The clouds will continue to push across the area, with an isolated rumble of thunder possible from time to time, but most will stay dry this evening.
It will be another hot and humid evening with isolated storm chances! As of 4:30PM, many locations are seeing temperatures in the 90s with heat index making it feel like the triple digits. Isolated storms have begun developing to the Northwest, but are only moving at 20 mph.
If those storms maintain their strength, they might approach the Stateline after 6PM. Highest storm coverage may remain North of Rockford, but we will maintain a 20% chance through the late evening.
Either way, it will be rather humid start for those Friday night football games, whether they start at 7PM or are delayed to 8PM. Temperatures will remain in the 80s through at least 9PM where storms do not cool things down. Isolated storms remain possible through this time, but highest coverage will remain mainly North of the Stateline.
Heat and humidity will unfortunately stick around for another day here across the state line with the 4th day in a row of 90° temperatures on tap. Dewpoints won't offer any relief either as temperatures will be in the low 70's which will send heat advisories near and above 100° once again today. Because of this, heat advisories are in effect through 10pm this evening so make sure to continue to practice heat safety once again.
Thankfully, some relief does look likely into the weekend thanks to a higher-pressure system that's expected to move in by Saturday. This high pressure will be making its way out of Canada so as it makes its way south, drier and cooler conditions from the north will be dragged down to the Great Lakes region.
Temperatures over the weekend will drop below the 90° mark however we'll still be above average with temperatures each day. Either way, conditions should become more comfortable through the weekend thanks the higher pressure which should offer great conditions for Labor Day Festivities!
It's been a sizzling start to September across northern Illinois and southern Wisconsin, with summer refusing to loosen it's grip. Tuesday brought one of the hottest days of the year so far, as Rockford soared to 96 degrees under strong sunshine and a persistent southwesterly wind. Adding to the discomfort, both September 1st and September 2nd featured peak heat index values above 100 degrees.
3rd Heat Advisory:
With the heat continuing, a third heat advisory has been issued for all of our northern Illinois counties. Unlike the previous two advisories, this one is abit longer-lived, having gone into effect this morning and remaining in placeuntil 9PM this evening.
Toasty Thursday:
Afternoon temperatures will once again climb into the upper 80s and low 90s, while humidity levels push heat index values into the 100to 105 range. With another day with dangerous heat expected, make sure heat safety remains a HUGE priority. If you'll be spending an extended time outdoors, be sure to stay hydrated, drink of water, and take frequent breaks in the shade or air conditioning.
Now, the one thing that could "spare" us from the heat would be thunderstorm chances which we have this morning and then again this evening into tonight. Like yesterday however, the jet is oriented in a way where the highest potential is displaced to our north across portions of Wisconsin, hence the level 2 Slight Risk for scattered strong storms. Roughly two-thirds of southern Wisconsin and most of northern Illinois are under a level 1 of 5 Marginal Risk for severe weather, indicating that any threat for stronger storms locally will be more isolated in nature.
The early September heat has really packed a punch, with two days each reaching into the mid-90s! That heat will fuel the potential for at least some isolated thunderstorms in the coming days, beginning Wednesday evening and overnight. While most will remain dry, a stray shower or storm may be possible from time to time. Outside of storms, it will remain very warm and humid, with overnight lows only dropping into the mid-70s.
Much of the daytime Thursday will once again be dry, hot, and humid. Afternoon temperatures will likely surge into upper 80s and low 90s for some. Isolated storms may be possible during the afternoon and evening, with highest coverage across Southern Wisconsin. Where it doesn't rain, heat index values will likely push into the triple digits again.
Any other chances for storms will depend on placement and evolution of previous rounds, but higher coverage looks possible Thursday night into Friday. There will be a fair bit of dry time in between rounds, but periodic thunderstorms are possible into the holiday weekend.
Future-cast has the Thursday night round mainly North and Northeast again, but the ingredients for a couple storms will be in place for much of the area. A few stronger storms may be possible, with a low-end risk for severe weather. Strongest storms may be able to produce damaging wind gusts and large hail, as the Storm Prediction Center maintains a Level 1/5 Marginal risk overhead for Thursday into Friday morning.
Showers and storms may be ongoing Friday morning and could persist into the daytime. If storms track over the same regions as the couple nights before, flash flooding may be a larger issue. If showers linger into the afternoon, temperature could be limited to the upper 80s Friday. But if things dry out quicker, another 90-degree day is on the table.
Temperatures climbed to 94 degrees in Rockford on Tuesday, making it the hottest day of the year so far, and while today's high temperatures may end up a degree or two lower, oppressive humidity will keep conditions feeling much hotter.
A heat advisory will once again be in place for all of northern Illinoisfrom 12PM-9PM. Heat indices are expected to reach between 100° and 105°, possibly as high as 110° this afternoon, creating dangerous conditions for anyone spending time outdoors. Like yesterday, be sure to stay hydrated, take frequent breaks in the shade or air conditioning, and remember that little relief from the heat is expected overnight as temperatures only fall into the low 70s.
The heat and humidity are making a big comeback across the Stateline today, prompting a Heat Advisory from 12PM until 9PM for Winnebago, Boone, Ogle, Lee, DeKalb, McHenry, Carroll, and Whiteside Counties. As of this moment, the heat alerts do not extend into southern Wisconsin.
Temperatures this afternoon will climb to around 90 degrees, but the bigger story will be the humidity. With dew points in the low to mid 70s, it feel considerably hotter, with heat index to 100 degrees or higher for several hours this afternoon. If you are spending time outdoors, be sure to take frequent breaks, stay hydrated, and limit strenuous activity during the hottest part of the day. Don't expect much of a cooldown tonight. Temperatures will be slow to drop, only settling into the low 70s.
Hot Start to September:
The heat won't completely let up after today. A strong late-summer ridge will drift eastbut at the same time, leaving low-level flow out of the southwest. This will keep temperatures running well-above average through the second half of the week.
Highs will end up in the low 90s Wednesday before easing slightly into the upper 80s Thursdayand Friday. While air temperatures may come down a bit later in the week, the humidity isn't going anywhere. Heat index values are expected to climb into the 100 to 105 degree range on Wednesday, then remain above 90 degrees Thursday and Friday, making it feel several degrees hotter than the thermometer suggests. Again, be sure to practice heat safety during the prolonged hot stretch.
A few non-severe thunderstorms have developed within the last couple of hours of over northern Illinois producing mainly locally heavy rainfall and frequent lightning. The threat for these storms to turn severe remains very low.
A weak little ripple, or upper-level wave, in the jet stream is currently moving across the Midwest and has provided just enough force in the atmosphere to allow some of these storms to develop. But with the atmosphere remaining 'capped' the threat for the storms to grow to severe limits remains very low.
These widely scattered thunderstorms will continue through this evening, roughly through 8pm or 9pm. Overnight there does remain an isolated chance for a couple storms, but we may see a better chance for more storm coverage late Tuesday into Wednesday.
Temperatures have warmed into the mid and upper 80s, with the heat index pushing the mid-90s in a few spots. But expect temperatures to briefly drop as the rain moves through. Unfortunately, it won't clear some of the humidity we are experiencing this afternoon.
We haven't used the phrase "Ring of Fire" in quite some time, but itmakes a return as we round out the month of August and start September. What does this mean? Expect temperatures to climb close to the 90-degree mark through the first half of the week. Since we're positioned along the northern edge of the ridge, we'll also need to keep tabs on storm potential. Weak systems ridging around the ridge may occasionally trigger showers and marginally-severe storms.
Current Heat Alerts:
As of this morning, no counties across the Stateline are under any heat-related alerts. However, the heat is becoming more intense farther to our south and west where Heat Advisories are in place. Again, pending storm chances, we may see that expand into northern Illinois but for now, we have no alerts.
Today's Heat:
For today, expect mostly cloudy skies to gradually become partly cloudy as the day goes on. A weak system arriving late in the afternoon and evening could be enough to spark up an isolated shower or storm after 3-4PM. Now, with the ridge anchored to our south, a large reservoir of warm air is spreading into the low levels of the atmosphere.
That warm air acts like a cap, limiting thunderstorm potential for much of the day and keeping any storm chances isolated and confined to the late afternoon and evening hours. Temperatures will climb into the upper 80s, and with humidity continuing to increase, it will feel more like the low 90s. Overnight, storm chances will lower after midnight, allowing skies to turn partly cloudy with lows in the low 70s.
Tomorrow's Heat:
Tuesday will bring another hot and somewhat humid day to the Stateline. Like today, high pressure and the cap will keep daytime storm chances at bay for the most part, allowing temperatures to climb close to the 90-degree mark. With dew point values sitting in the low 70s, heat indices could end up in the mid to upper 90s at times Tuesday afternoon. Forecast models do show a disturbance pushing through late in the day towards the evening. This could again be enough for us to see an isolated chance for a shower or thunderstorm.Wednesday may end up being the hottest day of this upcoming stretch as highs may end up a degree or two past the 90-degree mark.
Showers have been a little more widespread this afternoon than I was expecting, limiting temperatures to the mid/upper 70s like yesterday. Many locations in the Stateline picked up between a quarter inch and an inch of rainfall from late Saturday night through Sunday evening, with light showers continuing for some as of 5:30PM.
We will keep the light showers with pockets of heavy rain into the evening and night, but likely in lesser coverage than the daytime. Temperatures will hold steady through the night, only falling into the low 70s.
Increasing humidity will bring a noticeable summer-like feeling this week, with isolated thunderstorm chances to boot. The heat and humidity will be characterized by a rise in dew points, pushing into the 70s at times. With a very warm air mass just above the surface, temperatures will rise near 90 degrees some days, pending thunderstorm development. As for storm chances, the daytimes will be mainly capped and dry each of Sunday, Monday, and Tuesday. The evening and overnight periods may bring slightly better coverage of rain. Whenever they develop, the strongest storms may be strong to severe.
But the storm development is far from a guarantee. This is because of that very warm air above the surface mentioned above, otherwise known as a "cap". This effectively acts as a lid on the atmosphere which can work to prevent thunderstorms from developing. If we were to be capped during the day, the temperature would likely be able to reach its maximum, pushing near or above 90 degrees. Conversely, if the cap is weaker or breaks, thunderstorms may be able to develop. This would promote slightly cooler afternoons with highs in the middle or upper 80s, but likely still rather humid.
Because of the small-scale nature of this cap, models will likely change a lot each day, promoting wildly different rain chances even within the same day. In short, we may see isolated thunderstorm development anytime starting Saturday night through Monday evening. But much of that time will be dry.
The first wave may arrive early Sunday morning in the form of some scattered showers and a few embedded storms. Depending on how long this lingers into the afternoon, temperatures may not quite reach as high.
Chances drop off for the evening a bit, but higher coverage may return overnight and Monday morning. Another chance looks to develop Tuesday morning. Similar to Sunday, the afternoon temperature depends on how quickly the clouds and rain thin out, and if the cap holds for the afternoon. If we remain dry, temperatures will likely push near 90 degrees Monday and Tuesday afternoons.
While the warmth over the last week has not come with much humidity, that is about to change in the coming days. While Saturday will remain somewhat comfortable with clouds and slim chances for rain, the humidity really builds in after Sunday.
Sunday will begin the first of several hot and humid days, with temperatures pushing into the mid-80s. The heat index will make it feel a bit warmer, possibly near 90. Monday through Wednesday will be even hotter, with near 90-degree highs possible each day. The peak heat index will likely be well into the 90s, and possibly close to 100 degrees at times.
Normally when you have excessive heat and humidity like this, you will see storm chances not far away. The Stateline will be right on the edge of the more active jet stream aloft. This acts like the highway for storms to form and maintain themselves on. South of us, the atmosphere will likely remain capped each day, preventing storm activity. With the active jet centered mostly around Central and Southern Wisconsin, the Stateline itself will have a chance for rain each day, but the highest concentration of storms may remain just to the North. If this jet stream were to shift South even a bit, storm chances will increase each day with slightly lower concerns about the heat.
A line of decaying storms will approach the Stateline by mid-day Saturday, bringing the potential for at least some light showers mainly between 11AM and 5PM. The threat for thunder will be near zero, but a few pockets of rain may bring a brief steady shower. Outside of that, light sprinkles will be the primary form of precipitation. Any rain we do see will begin to clear by 5-7PM. The bigger impact the rain will have is on the temperature. We may not quite reach the 80s with the clouds in place during the peak heating hours of the day.
The rain that does fall will not amount to much, with most seeing under a tenth of an inch. Better chances for 0.1-0.2" of rain will be primarily Northwest of Freeport. Some locations in the Stateline may not even see any measurable rain at all. Higher chances for rain and storms may be possible toward the end of next week, following increased heat and humidity.
Mother nature really delivered this week, treating the Stateline to several comfortable days with afternoon highs settling in the low to mid 80s. We'll wrap up the workweek on a similar note, with skies remaining dry and partly cloudy and temperatures climbing into the low 80s, right around 83 degrees.
Even better, Friday evening/night plans look weather-friendly. Unlike last week, there are no thunderstorms or rain in the forecast, meaninghigh school football games across the area should kick off and finish without interruption. The dry and pleasant conditions are also great news for anyone heading downtown for City Market, with comfortable temperatures lingering into the early overnight hours.
Weekend Outlook:
This quiet weather pattern won't disappear entirely over the weekend, but most of us will stay dry. Our next disturbance arrives around or just after midday Saturday, bringing the chance for an isolated shower or two during the afternoon.
Even so, the better rain chances and moisture will stay north of the Stateline, focused across central and southern Wisconsin. As a result, many location across northern Illinois may end up seeing a few clouds and a sprinkle. Sunday brings a similar setup, though temperatures will be a touch warmer as a ridge of high pressure aloft pushes east across the midsection of the lower 48. This will allow highs to climb into the upper 80s. A pop-up shower or isolated thunderstorm cannot be ruled out, but rain isn't expected to be widespread. If you have outdoor plans, keep an eye on the heat but also the radar.
Meteorological Fall:
As we turn the calendar from meteorological summer to meteorological fall on September 1st, the weather certainly won't be following suit. In fact, the average high for early September hovers around the 80-degree mark, but temperatures will run well above that mark as an upper-level ridge settles across the Tennessee Valley and the Deep South States.
That ridge will allow summer-like heat to build into the Stateline at the start of next week, sending highs back near the 90-degree mark.
