Near record heat on tap Tuesday, major changes to follow

Coolest temperatures since mid-May likely Thursday
Published: Sep. 19, 2022 at 9:49 PM CDT
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ROCKFORD, Ill. (WIFR) - It’s hard to imagine a day much more pleasant than Monday proved to be in the Stateline. Abundant sunshine prevailed from start to finish, allowing temperatures to reach the lower 80s once again. What’s more, northeasterly winds allowed for greatly reduced humidity compared to Sunday.

Pleasant conditions have continued into Monday evening, though a weak disturbance has ignited a cluster of showers and thunderstorms over Iowa. Thankfully, there’s been a significant weakening trend in this activity, though we cannot entirely rule out one or two of these showers reaching our area late Monday evening or very early Tuesday morning.

Clouds may squeeze out a few showers later Monday evening.
Clouds may squeeze out a few showers later Monday evening.(Mark Henderson, WIFR)

Sunshine is to prevail once again Tuesday, with just a few clouds from time to time. Winds are to shift to the south, and will blow with increased gusto as the day progresses. That’ll not only allow temperatures to surge, but humidity levels will be escalating as well. The current forecast high temperature of 91° would fall just shy of a record that has stood for more than a century. The 92° record for September 20 was set all the way back in 1920.

Showers and thunderstorms will flirt with the Stateline Tuesday morning, but appear to be more...
Showers and thunderstorms will flirt with the Stateline Tuesday morning, but appear to be more likely to our north.(Mark Henderson, WIFR)
Sunshine and a gusty southerly wind will allow temperatures to warm very quickly Tuesday.
Sunshine and a gusty southerly wind will allow temperatures to warm very quickly Tuesday.(Mark Henderson, WIFR)
Temperatures Tuesday appear likely to reach 90° for the first time since early August.
Temperatures Tuesday appear likely to reach 90° for the first time since early August.(Mark Henderson, WIFR)
Humidity will be a major factor Tuesday afternoon.
Humidity will be a major factor Tuesday afternoon.(Mark Henderson, WIFR)

The warm, humid environment will provide just enough energy that a few showers and thunderstorms may develop in the afternoon hours Tuesday, though that’s far from a slam dunk. With so much warm air present aloft in the atmosphere, there’ll be a “cap” present, which very often suppresses thunderstorm development. That’s why we’re placing the chances for showers and storms at just 20%. Should storms actually develop, the chance of them becoming severe appears to be very, very low.

Showers and a few thunderstorms may pop on Tuesday afternoon.
Showers and a few thunderstorms may pop on Tuesday afternoon.(Mark Henderson, WIFR)
Should any storms affect the area, it'd be extremely unlikely for them to become severe.
Should any storms affect the area, it'd be extremely unlikely for them to become severe.(Mark Henderson, WIFR)

Quiet conditions are likely for most, if not all of Tuesday night. It will, however, remain warm and quite muggy. Temperatures aren’t likely to fall much below 70° overnight, and humidity levels will remain uncharacteristically high by late September standards.

It'll still remain rather uncomfortable for most of the night Tuesday.
It'll still remain rather uncomfortable for most of the night Tuesday.(Mark Henderson, WIFR)

Wednesday’s to kick off on a warm and muggy, albeit cloudy note, as a cold front slips in from the northwest.

It may still feel rather muggy as we wake up Wednesday morning.
It may still feel rather muggy as we wake up Wednesday morning.(Mark Henderson, WIFR)
The front passes through the area early Wednesday, shifting winds to the north and northwest.
The front passes through the area early Wednesday, shifting winds to the north and northwest.(Mark Henderson, WIFR)

Clouds are to dominate most of the day Wednesday, and an increasingly cool northwesterly wind will blow as the day progresses. Not only will temperatures be steadily falling during the day Wednesday, humidity levels will drop considerably as well. From a precipitation standpoint, the expectation is that the vast majority of the day will be dry. However, a few errant showers can’t be entirely ruled out at any point in the day.

Much more comfortable conditions are expected Wednesday afternoon.
Much more comfortable conditions are expected Wednesday afternoon.(Mark Henderson, WIFR)
Showers can't be ruled out entirely on Wednesday either.
Showers can't be ruled out entirely on Wednesday either.(Mark Henderson, WIFR)

Even cooler temperatures are to follow as skies clear Wednesday night. Lows are to fall into the middle and upper 40s Wednesday night as a sprawling Canadian high pressure system enters the nation’s midsection. While that high pressure system promises a good deal of sunshine for Thursday, it also promises to produce the coolest high temperatures here in almost exactly four months! The last time we had a high temperature cooler than Thursday’s forecast of 63°, you’d have to go back to May 21, when temperatures reached just 62°.

Temperatures Thursday are to only reach the lower 60s.
Temperatures Thursday are to only reach the lower 60s.(Mark Henderson, WIFR)

Thursday night may feature temperatures in the upper 30s in some of the coolest outlying locales, while a low of 42° is in the cards for the City of Rockford proper. Friday’s to feature a modest temperature recovery, though it’s also to feature extensive cloudiness. What’s more, Friday also appears to feature the best chances for rain of the week, which could, for the first time in 2022, present complications for Friday night’s Football Frenzy. It’s a development we’re certain to be monitoring as the week progresses.