Record warmth Monday afternoon

Despite a cold front moving through early Monday afternoon highs across the Stateline warmed into the mid and upper 80s, reaching 90 degrees in Rockford.  Our high of 90 degrees broke the previous record high of 89 degrees set back in 1954, and was the warmest Rockford has been this late in the year since a high temperature of 90 degrees was recorded back on October 9th, 2010!

 Blocking high pressure in the upper levels of the atmosphere, and persistent high pressure over the eastern Great Lakes at the surface will keep skies mostly clear and temperatures well above average.  An 'omega block' in the jet stream - because it looks like the Greek letter omega - will focus the heat across the middle of the country, keeping high temperatures in the low to mid 80s through the end of the week.  While close, it does appear that the record highs for Tuesday, Wednesday and Thursday should remain in place; record high for 9/28 - 91°, 1952  - 9/29 - 94°, 1953 and 9/30 - 92°, 1971.  Forecast highs: 84°, 87° and 87°.

That, combined with the ongoing drought conditions, is just a continued recipe for above average temperatures, as well as continued dry conditions. By Friday the blocking ridge will begin to break down as a slight increase in moisture will be found as low pressure lifts north from the Southwest.  High pressure to the east will keep the majority of the moisture west of the Stateline, however, with just a slight increase in cloud cover Thursday and Friday.

 

Dry, & Warm Weather Pattern Caps Off a Very Dry September

Very Dry September:

Just as quick as we were to jump into the month of September, we are sitting a few days away from jumping into October. Can you believe it? However to our surprise, September has featured no relief in the form of significant rainfall to help with the very dry year we are having. 

Hence why a good chunk of northern Illinois and southern Wisconsin remain under a D2 moderate drought. As of this morning, the 0.53" of rain that the Rockford International Airport has seen this month ranks 9th for driest Septembers on record. With the way the weather pattern is looking as we jump into October, it doesn't look like that total ain't going to budge much. 

Sun-Filled Stretch:

No need for a light jacket if you are planning to leave the house early today. Temperatures, thanks to a light southerly wind, are kicking off on a comfortably warm note in the low to mid 60s. With high pressure mainly in control of our atmosphere, today features plenty of sunshine with highs back in the low to mid 80s. Normally in late-September, our average highs are falling into the low 70s.

A cold front coming in late in the day may bring a few more clouds and a light breeze to the area during the evening hours. However, with no moisture to work with, this cold front will sneak through our area bone-dry. 

What we do see though is a slightly cooler air-mass filter in from the north, resulting in a small drop in our overnight lows and daily highs for Tuesday. It'll be a "light jacket" type morning as most of our spots will wake up in the low 50s. With an easterly component to our surface winds, highs will top out in the low 80s under plenty of sunshine. 80s look to be the name of the game for the rest of the work week, with a slight cool-down expected for the upcoming weekend. One thing that continues to avoid the Stateline is rain chances.

Dry Moving Forward:
 
Models have been consistent over the past few days on a strong ridge of high pressure sliding in early Wednesday, remaining in control through Thursday. This will help steer any systems away from the Stateline, keeping rain chances very low as we prepare to jump into October. 

So it looks more than likely that this September will be written down as one of the top 10 driest on record. There are hints of a slow-moving low pressure system coming in at the end of the work week and for the start of the weekend, possibly bringing us a very slim chance for a few isolated showers and thunderstorms. But these chances by no means come in the form of a washout.

Drought conditions worsen across northern Illinois

 
The lack of rainfall is really taking a toll across much of northern Illinois.  The latest drought monitor shows that the drought conditions have worsened across much of northern Illinois, with now portions of DeKalb, Ogle, Lee, Carroll and Whiteside counties experiencing severe drought conditions.  A small portion of far northeast Illinois, Lake County, is experiencing extreme drought conditions.

 While there has been some rain within the last week, it hasn't been nearly enough to help ease the extremely dry conditions across the region.  In September along we've only received 0.36 inches of rainfall, putting us at a 2.55 inch deficit.  For the year, Rockford has only received 15.86 inches of precipitation, when normally by this time of year we should be closer to 30 inches.  This puts us over a foot below our year to date average, making the period from January 1st to September 22nd, 2021, the driest year to date on record.  Now there were two other years, 1920 and 1946, that had less year to date precipitation but there is quite a bit of missing data during the Spring and Summer months of those years.

The second driest year to follow this one would be 1988 with only 16.60 inches, and then 1934 with only 16.75 inches.  For many we remember 2012 as being a very hot and dry year; year to date it came in as the 5th driest with 17.84 inches. 

According to the National Weather Service, volunteer weather observers across northern Illinois indicate that stream flows in some of the area creeks and streams are much lower; specifically along the Kishwaukee River and Beaver Creek.  Over the last 30 days we've only received 25-50 percent of our average rainfall, leading to the deteriorating drought conditions across the region.  Soil moisture is also very low, estimated at only 1-5 percent of average.  While there will likely be some rain Friday evening with the passage of a cold front, the next seven days (and beyond) are looking very dry.  And the rain we get Friday evening will remain under half an inch.  Extended outlooks from the Climate Prediction Center have a high probability for below average precipitation through the beginning of October, with above average temperatures.

Windy Days Ahead, Temperatures Get a Case of the "Ups & Downs" into the Weekend

Feeling Very Fall-Like:

At exactly 2:21PM Wednesday afternoon, we made the seasonal transition from Summer to 🍁 Autumn 🍂, and it definitely felt like it to. 

A blustery wind out of the north limited our high temperatures to the mid to upper 60s, making for the first 60-degree day since July 8th. As we prepare to jump into the first full day of Autumn, a repeat of Wednesday's weather can be expected before temperatures get a case of the "ups and downs" into the weekend.

Another Breezy Day:

For those heading out early, you'll likely want to grab or put on something warm. Fall is definitely making it's presence known this morning as we're is waking up to temperatures in the 40s. Some areas to the north in central and northern Wisconsin are under a FROST advisory this morning. Thankfully, our temperatures will be too warm for an advisory to be issued locally.

A pesky upper-level low over the Great Lakes region will continue to swirl in cloud cover, especially for areas along and east of I-39. But as high pressure inches closer from the west, the clouds we see during the morning hours will give way to increasing sunshine this afternoon. Winds however will still be a big part of today's forecast, as north-northwest winds will be capable of gusting up to 25 mph at times. This will help bring another day in the mid to upper 60s before warmer winds take over for Friday.

Windy Days Ahead:

By Friday morning, the same high pressure system is expected to shift to our southeast, allowing winds to switch to the southwest. Ahead of an approaching cold front, the pressure at the surface will tighten, allowing winds to ramp up once again for the afternoon hours. 

Winds could peak around 25 to 30 mph, pushing our daily highs near or at the 80-degree mark. Along with this cold front does come a chance for a few showers, mainly during the late-evening and early overnight hours. Conditions look to rapidly dry out and cool-down into Saturday, with temperatures back down near 70-degrees. 80s do make a quick return beginning Sunday, continuing well into next week.

Up and down temperatures expected with blustery, changing wind direction the next few days

The official start to Fall began Wednesday afternoon and Mother Nature sure didn't disappoint with more a more fall-like air mass.  Temperatures went from the upper 80s and low 90s this past Sunday and Monday, to highs below 70 degrees Wednesday afternoon.  Rockford's high officially came in at 69 degrees, following Tuesday's high of 70 degrees.  It felt nice, but the strong north wind at times definitely put a chill in the air. 

Winds will remain strong the next few days thanks to a departing low pressure system, currently moving through eastern Illinois and Indiana Wednesday evening.  This low will park itself over southern Michigan by Thursday morning before quickly exiting to the northeast by the end of the week.  High pressure centered over the Midwest will slowly be moving in and the difference in pressure between the two will keep the winds strong Thursday.  Northwest winds will gust as high as 25 mph throughout the afternoon, holding temperatures in the upper 60s.  Cloud cover will likely keep the area split again, with locations to the east experiencing a little more cloud cover than locations to the west. 

 Winds will then shift around to the southwest Friday as the high slides to our south and east.  A cold front advancing in from the northwest and west Friday evening will gradually bring an increase in cloud cover, but also a return to slightly warmer temperatures.  Following Thursday's high of only 69 degrees, highs on Friday will warm close to 80 degrees, only to drop once again Saturday as winds shift back around to the northwest for the afternoon.

It is this time of year when we tend to see big changes in our daily temperatures as our seasons begin to change.  That's because the jet stream is strengthening and becoming faster and stronger.  This is what helps to pull in the colder air from the north, or draw up the warmer air from the south.  The stronger winds in the jet stream often times leads to stronger and deeper storm systems, which can cause gustier winds from time to time.  By the end of the weekend our winds should ease a little, but could pick right back up as another storm system moves across the country.

Cooler-Than-Average, Breezy Stretch Continues as we jump into Autumn

Fall-Like End to Summer:

Remember how we were hinting at big changes with Tuesday's frontal passage? Well, we really meant BIG changes. Rockford saw it's daily high temperatures go from the low 90s Sunday, to just barely hitting the 70-degree mark yesterday. 

In fact, a glimpse at the almanac shows that yesterday's high of 70-degrees was the first time since September 4th that the airport observed a below-average high. In other words, summer has been in control for much of the month of the September. However, I am happy to say that there is nothing summer-like about the forecast as we head into the first few days of fall. 

Jumping Into Fall:

Now, for those that are wondering, the fall equinox doesn't actually occur until 2:20 this afternoon. At that time, the sun's most directed rays will be centered right over the Earth's equator. When the day comes for an equinox to occur, daylight hours and nighttime hours are roughly the same, just one outnumbers the other by a matter of minutes. Come this weekend, nights will be longer than days until next year’s Spring Equinox.

 Cooler, Breezy Stretch:

Two systems will be battling it out to determine who sees more sunshine, and who see more cloud cover as we jump into fall.Thanks to a stationary low-pressure system over the Great Lakes, areas along and east of I-39 will have a better opportunity to see a few more clouds throughout the day. But, as high pressure approaches from the west, this will help slowly bump this low-pressure system away from the area, allowing clouds to decrease a little into tonight. With the pressure tightening up between the two systems, winds will become a bit gusty once again for the afternoon hours. Winds out of the north, and sometimes out of the northwest, could gust up to 25 to 30 mph at times. This will limit our high temperatures to the upper 60s, making for the first 60-degree day in Rockford since July 8th.

More of the same can be expected as we roll into Thursday, but winds won't be as strong. Highs look to remain in the upper 60s, close to 70-degrees before making a quick jump towards the 80-degree mark on Friday. As mentioned before, it does look like Friday begins on a sun-filled note, with clouds increasing late in the day. 

This is in response to a secondary cold front that slides in Friday evening, bringing with it a couple of showers. With that being said, it doesn't look like the chance we see will be in any shape or form of a wash out. Rain chance look to slim to none after Friday, as another high pressure system settles in.

Fall-Like Weather Settles in Just in Time for the Seasonal Transition

Ready For Fall?:

It sure was a loud night across the Stateline as a strong cold front shoved a round of showers and thunderstorms in from the west. While there were a few "Special Weather Statements" issued by the National Weather Service, a majority of the Stateline area was able to avoid severe weather. Even with the frontal boundary to the east of the region, a stray shower or two remains possible during the morning hours. Otherwise, prepare for cooler days and cooler nights as this frontal passage marks the beginning of a very fall-like stretch. 

Cloudy, Breezy Tuesday:

While astronomical fall doesn't officially begin until 2:20PM Wednesday, we'll get a little taste of it for the last day of summer. How fitting right? The combination of lingering cloud cover and a robust northwesterly breeze will limit highs to the upper 60s and low 70s. For those that are keeping track, highs this afternoon will top out roughly 15° to 20° cooler than our high temperatures from yesterday. As skies slowly clear out overnight, temperatures will fall into the mid to upper 40s by the pre-dawn hours Wednesday morning, making for an even cooler start to the day. But the temperature drop doesn't stop there.

Cooling Down Big-Time:

Guidance continues to show the "coolest" air with this incoming air-mass sliding into the region late tonight into Wednesday morning. Despite a sun-filled forecast, highs will have a tough time climbing out of the 60s for most. If this were to verify, this will the first time since July 8th that the Rockford International Airport observed a 60-degree high. More of the same is expected for Thursday, with a few more clouds filling our skies. Thanks to a low-pressure system occluding over the Great Lakes, there will be a slim chance for a late-day shower or thunderstorm. A slight chance will also be in the works for Friday as a secondary cold front looks to march through the Stateline. Rain chances after that look very very slim.