Buckle up! Northern Illinois to see multiple clipper systems into next week

Get ready folks! We're about to be put on a carousel that will send multiple "clipper-like" systems out way. The first arriving over the weekend. 

Before clipper system #1 arrives, we will see a cold front move in overnight into Saturday. Ahead of it will be the opportunity for snow, possibly a scattered rain/snow mix this evening into tonight. The best time frame will be an hour or two after sunset, with chances lingering into midnight. 
 

Saturday should begin with some sunshine, though we can expect clouds to build in during the afternoon. Also ahead of this system, the National Weather Service has started to dish out winter alerts. Mainly across northwest and central Iowa. 

 

  

Forecast models then show snow showers tracking in late in the evening Saturday, with chances lingering into the first half of Sunday. 

 

 

 

Generally, I think this system will be very similar to the one that came through earlier in the week, leaving behind 1" to 3" snowfall totals. The axis of heavier snow should be to our south and west. 

 

 

Following this weekend's clipper system, there will be a another brief push of cold Arctic air. This will keep highs in the20s Sunday with overnight lows falling near the 0° by Monday morning. The system "carousel" continues as we can expect a 2nd system to arrive late Monday followed by a 3rd system Wednesday. Models still have disagreements on the overall track of the system scheduled for Wednesday. The track will determine if we're in for a scattered snow showers or a rain/snow mix. 

Rockford ties record low temperature overnight

This stint of Arctic air is on its way out, though it couldn't leave without bringing breaking news to the temperature department. 

Shortly before midnight, the thermometer at the Rockford Airport fell to -4° which ties the record low for December 4th set back in 1991.

In comparison to the last 4 meteorological winter seasons, this is the earliest Rockford has observed a sub-zero low temperature. The next closest was the 2022-2023 season where the airport fell to -10 on the December 22nd. That Arctic stint would linger into the Christmas holiday. 

Slowly thawing out Friday, light wintry mix possible late

 Despite the bright sunshine of Thursday, temperatures were only able to reach the teens including 14 degrees in Rockford. Quickly as the sun set, temperatures shot down into the single digits and below zero. Wind chills were as low as -15 degrees for the second night in a row. But as arctic high pressure pulls out of the area, we will see an increase in "warmer" Southwest winds. This will aid to bring temperatures back to the teens by 8-9AM and mid-20s for the afternoon high.

Next chance for some flurries or light mix will arrive Friday evening-night, with the bulk of precipitation remaining North of the Stateline. We will only see influence from a weaker cold front here, keeping precipitation on the lighter side. Better chances for snow will arrive Saturday night with a potential for a couple inches of accumulation.

Bundle up! Coldest afternoon since late-February

February 19th. That was the last time Rockford saw afternoon highs fail to reach the 15° mark. In fact, the observed high that day was 11° which is going to how cold we will be this afternoon. 

 

 

  

Thanks to the radiational cooling process, the day for most begins in the single-digits. Wind chills however are sitting below zero for some. Pack those layers if you are heading out this morning. 

As previously mentioned, afternoon highs will barely make it out of the single-digits. On the flip side, high pressure overhead will make for less cloud cover and more sunshine. Again, the main priority weather-wise will be getting prepared for this Arctic chill.

Another bitterly cold night lies ahead. However, the coldest part will be this evening. Once this area of high pressure is positioned to our east over the Ohio Valley, surface winds will take a turn to the south and southwest. This will allow our temperatures to slowly climb as we get into Friday morning. Wind chills will also be at their lowest during the evening, gradually climbing towards the 0° mark.  

 

High temperatures Friday are expected to peak in the low 20s ahead of our next cold front. Forecast models bring said cold front in Saturday morning, setting the stage for more cold over the weekend. 

 

 

  

Afternoon highs will remain the 20s, dipping into the teens Saturday night and then into the single digits Sunday night. Also coming in will be our next storm system which will track in in a very "clipper-like" way Saturday evening into Sunday. With the cold in place, this would favor another opportunity for the Stateline to see wintry precipitation. Unlike the winter storm from last weekend, the axis of heavier snow will be to the southwest of the region.

Bitter cold ahead, active "clipper" pattern to follow

 Following a strong arctic cold front Wednesday afternoon, temperatures are set to plummet as clouds will thin out. Overnight lows will drop down toward zero, while wind chill values will make it feel closer to -10 or -15 by early Thursday morning!

While the afternoon high temperature Thursday will return back to the low teens above zero, wind chills may remain closer to zero even under a very light breeze. Temperatures again drop toward zero Thursday night, with wind chills down around -10.

The overnight low temperatures below zero the next two nights would be the earliest in the season we have seen subzero temperatures since 1991! Forecast lows will return to the teens by Friday night with our next weather system passing overhead.

The Stateline will be toeing the line of much colder air to the North and milder air to the South. This will funnel several "clipper" systems our direction over the next week, with each of them featuring a slim chance for snow or mixed precipitation. The most favorable windows for wintry precipitation in the near term appear to be Friday into Saturday, then Saturday into Sunday.

Patchy blowing and drifting snow Wednesday morning

 

Southerly winds increased late Tuesday evening causing some patchy blowing and drifting snow across northern Illinois and southern Wisconsin. Most of this has been occurring in the open and rural areas but some roads - both in the north/south and east/west directions - have experienced drifting. Main roads will probably be okay.

This will cause some patchy slick spots through the morning commute, likely through 8am to 9am as this is when the winds will be at its strongest. Take it slow if you encounter any snow on the road. As a cold front comes through mid-day winds will turn to the northwest. We'll likely see wind gusts back around 20-25 mph which will keep the threat for blowing and drifting snow through the evening.

Temperatures today will warm into the low 30s thanks to a 'warmer' start but will start to drop through the late afternoon and evening. You can already start to see the cold air building across the Upper Midwest and Plains early Wednesday morning, with an even colder air mass further north in Canada. The push of Arctic air will be short-lived, but mighty, as temperatures drop below zero Thursday morning.

Wind chills will sit between -15 and -20 degrees. Highs on Thursday will only warm to the low teens, dropping briefly back below zero Thursday evening before warming above zero Friday morning.  

Steady temperatures Tuesday night ahead of big drop Wednesday

 

Foggy and grey skies Tuesday afternoon were no help in warming temperatures as most locations remained in the upper teens and low 20s. Rockford's high temperature made it up to 22 degrees, 17 degrees below normal. While the dense fog from the morning did lift shortly after sunrise skies were still hazy into the afternoon, and we even managed to see a few flurries from time to time. Fog likely won't be as much of a concern Tuesday night thanks to an increasing southwest wind that, at times, could gust as high as 25 mph through the overnight.

This combined with cloudy skies will help keep temperatures on the milder side, with most locations staying in the low 20s. In fact, we could even see temperatures rise through sunrise Wednesday. But with the breeze wind chills will remain in the mid and upper teens, so it'll still feel cold when you head out the door.

Southwest winds will help bring temperatures into the low 30s ahead of a cold front that'll move across the region mid-day Wednesday. Right along the front there will be a few flurries and light snow showers, but little to no additional accumulation is expected from that. Winds will then turn to the northwest behind the front with an Arctic air mass moving in by Wednesday evening, causing temperatures to quickly fall through Thursday morning.

Overnight lows will fall below zero for the first time this season, with wind chills as low as -15 degrees Thursday morning. Sunshine should return for the afternoon Thursday, but it won't do much to warm us up as highs are expected to stay in the low teens.  

Coldest air of the season arrives behind Wednesday's cold front

Similar to Monday, the day is beginning with a round of dense freezing fog. Visibility for a few, such as Janesville and Sterling, are registering at a mile or less so please, travel with caution. 

 

 

  

On the flip side, today features a small break from the snow chances as of late. A weak area of high pressure slides into southern Illinois this afternoon, keeping conditions dry for our Tuesday. This may even result in some sunshine. However, surface temperatures will remain in the low to possibly mid 20s. 

 

  

Winds are expected to pick up overnight as our next cold front approaches from the northwest. This will allow temperatures to gradually rise into Wednesday morning, eventually leaving us with highs in the low 30s. Now, if you are tired of the snow, I'm sorry to say a scattered batch of snow showers will tag along with Wednesday's frontal passage. The best chance for any snow will be during the morning hours. However, this chance will not be as widespread and long-lasting as the previous two opportunities.  

The bigger headline with Wednesday cold front will be the dose of cold air that follows. This will be the coldest air of the season thus far.
 

 

 

Surface temperatures are expected to plummet into Thursday, landing below the 0° mark. Thursday's cold start will pave the way for a well-below average afternoon, with highs only climbing to 11°. The last time high temperatures failed to reach the 20° mark was February 19th, 286 days ago. Temperatures drop below zero Thursday night, though we should wind up back in the 20s by Friday.

Light snow beginning to fall across northern Illinois Monday

10pm Update: Radar continues to some light snow and flurries area-wide, but the back edge of the snow showers is moving across NW Illinois which has helped improve visibility some. With temperatures staying below freezing tonight, and possibly dropping into the low teens, roads will remain slick and icy for the commute Tuesday morning. Be prepared for any snow-covered roads during the morning, as well as black ice. Roads that appear wet or shiny may actually be black ice.

Our next item of concern will be the potential for the development of fog early Tuesday morning, especially if we see any sort of clearing during that time. We should see skies turn mostly cloudy by the afternoon and evening ahead of our next cold front that'll move through Wednesday. 

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6:30pm Update: While there have been some improvements in visibility over the last hour the light snow continues to fall. We'll see another round of steadier snow move in from the southwest, now currently over Carroll and Whiteside counties along with some steadier snow in Lee and southern DeKalb counties. The Rockford Airport has already picked up 0.7 inches, with some spots in our southern counties measuring just a little over an inch. This snow isn't fast to accumulate but will

continue to create slick and icy conditions out on the roads. Those icy conditions could continue through Tuesday morning, especially on the lesser traveled, back and country roads. 

 

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5pm Update: The light snow continues to fall, but there have been some improvements in visibility where the steady snow has lightened up just a bit. We'll continue to see the light snow fall through late evening, with only a few flurries around through Midnight.

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Original post: The snow won't be as intense as what we just finished up with this past weekend, but it will cause some issues for the afternoon and evening drive. Light to moderate snow has started to fall across northern Illinois and southern Wisconsin with the biggest impacts at the moment being reduced visibility. In fact, there was a quick drop in visibility once the snow started. For many, visibility ranges between 1-3 miles, with quick drops in visibility under the steadier snow from time to time can be expected.

A WINTER WEATHER ADVISORY is in effect for most of northern Illinois until Midnight as the light snow is expected to continue throughout the evening. Temperatures currently in the 20s will cause the snow to stick to roads, creating slick driving conditions through the afternoon and evening commute. Please be cautious while out on the roads through the rest of the afternoon and evening and allow yourself a little extra time.

December begins with patchy freezing fog, accumulating snow potential

ALERTS: The National Weather Service placed most of northern Illinois, Winnebago, Boone, Ogle, Lee, McHenry, DeKalb, Carroll, and Whiteside Counties, under a WINTER WEATHER ADVISORY. This will be in place from 2PM to midnight. 

  

TIMELINE: The big headline for the morning drive, patchy dense freezing fog. Along with low visibility, this could result in a few slick spots. Please use extra caution if traveling this morning. 

On the flip side, the rest of the morning will end up dry under mostly cloudy skies. It's not until we get into the early afternoon hours where scattered light snow will be pushing in from the west. Snow will linger into the late evening hours and likely wrap up entirely by the midnight hour. 

HOW MUCH: Fortunately, this will NOT be nearly as impactful as the weekend winter storm, but most locations will see between 1-3" of fresh powder. This will be a much lighter and fluffier snow, with snow ratios closer to 15-20:1, rather than the 11-12:1 we saw with the winter storm Saturday. Now, with surface temperatures already cold, anything that falls will likely stick onto roadways.

COLD THAT FOLLOWS: High temperatures today will peak in the low 20s. Same for Tuesday. Forecast models then show a cold front sliding through during the day on Wednesday. With it will come the chance for a few flurries and snow showers. However, we do see much colder air filter in behind it, leaving lows Wednesday night near 0 degrees and afternoon highs Thursday in the lower teens.