Snow flurries continue Monday evening

 

Not only did if feel more like December and January with wind chills Monday afternoon in the 20s and 30s, but for a time it also looked like it as our first snow of the season came down. The snow did not accumulate, but it did drop visibility for some during the afternoon. Scattered sprinkles/light rain and snow flurries will continue through sunset Monday evening, with mostly cloudy skies expected through the night.

The wintry weather is the result of a very deep, and

cold, low-pressure system over the eastern Great Lakes which has helped to pull down an unseasonably cold air mass into the Midwest, Great Lakes, and Northeast. This chill will remain in the place, minus the snow flurries, Tuesday and Wednesday before temperatures warm in a big way by the end of the week.

Even though the snow did not stick it was definitely a shock, and slightly earlier than when we typically see the first flakes fly in the Stateline. This usually occurs

towards the end of October (on average), around the 31st. The first *measurable* snowfall, a tenth of an inch or more, usually occurs mid-November, with the first one inch of snow occurring within the first week of December. Of course, we know here in the Midwest we can get our first snow at any point late in the Fall or Winter season. Skies remain mostly cloudy through the night with temperatures dipping into the upper 20s. Wind chills, however, will fall to the mid-teens Tuesday morning. Bundle up because it will feel cold!

First Flakes of the Season Could Fly Today, Record Cold Also on Tap

Early Week Pattern Change:

If' we've sounded like a broken record as of late, that's because N. Illinois and S. Wisconsin has seen nothing but thick cloud cover, gusty winds, and highs in the 50s the past few days. But a big change in our weather pattern moves in for the start of the work week. One that features possibly the first SNOWFLAKES of the season as well as a chill that we haven't seen since early-April!

Winter-Like Monday:

In a similar fashion to the past few days, our Monday kicks off with a few peeks of sun, with clouds gathering up quickly by midday. Along with the cloud cover does come a very small chance for precipitation, this time in the form of wet snowflakes. Yes. You heard me correctly. Any flurries that do manage to develop this afternoon will be widely-scattered in nature.

With a tight pressure-gradient still in place over the western Great Lakes, expect winds to remain strong out of the northwest. Temperatures because of this will struggle, with some of our local airports not making it out of the 30s. 

As mentioned previously, the forecast high of 40° would not only be a new record cool high for October 17th, but it would also be the coldest Rockford has been since April 2nd. In other words, prepare for a VERY winter-like day. While a few flurries may linger into the early overnight hours, expect skies to turn partly cloudy, with overnight low temperatures falling into the upper 20s.

Remaining Breezy:

A little more sunshine can be expected throughout the day on Tuesday. However, the additional sun we see tomorrow will bring little relief in the temperature department. With a decent northwesterly breeze still in place, highs will be limited to the mid to upper 40s. Again, wind chills will register in the mid to upper 30s. 40s look to continue into Wednesday before a significant warming trend takes over late in the week.

Record Cold Likely Monday, Chill Lingers into Wednesday

More of the Same:

In a similar fashion to Saturday, today will begin on a sun-filled note. However, the right ingredients will be in place for clouds to gather up towards the lunch hour, leaving N. Illinois and S. Wisconsin under a mostly cloudy sky this afternoon. High temperatures, because of the cloud cover and because of a rather breezy northwesterly wind, will be limited to the low 50s once again. But, expect wind chills to remain in the 40s during the afternoon. Partly cloudy skies stick around overnight, with lows falling back into the lower 30s.

Record Cold?    

Now, if you thought 50s was cold, just wait till the beginning of next week. A massive upper-level low over the Great Lakes looks to swing another shot of bitterly cold air our way, bringing down temperatures for Monday, Tuesday, and Wednesday. But the coldest air will be felt Monday and Monday night. For this time this season, the perfect atmospheric formula will be in place for record cold come Monday afternoon.

Highs for some will struggle to make it out of the 30s. Temperatures such as our forecast high of 41° is more typical for the end of November. 

And currently, our record cold high for October 17th is currently 44° and we likely will break that record. Not to mention that the strong northwest wind will also keep wind chills values in the 20s and lower 30s. BRRRR. Although conditions remain dry for Tuesday and Wednesday, forecast highs remain below the 50-degree mark, with overnight lows in the 20s and 30s. So, Prepare for a very chilly stretch!

Late-Week Warmth:

Now, with all this talk of some rather unseasonably chilly temperatures, there is some good news for all those warm-weather fans! To put it simply, "good things come to those who wait". 

Towards the weekend, a ridge out west look to significantly break down, allowing some of the trapped heat to spread across the midsection of the lower 48. This will allow temperatures locally to climb back into the 50s by Thursday, with near 70-degree weather possible by the weekend. Isn't that the most Midwest forecast you've ever heard of? Going from record cold to possibly climbing back towards 70-degrees.

More of the Same for Friday, Chilly Weekend Ahead

Another Breezy Day:

With a mature and massive area of low-pressure spiraling nearby, the Stateline really hasn't seen much of a break from the gusty winds as of late. 

In fact, Thursday marked the 3rd day in a row where Rockford observed a peak wind gust over 30 mph. Expect more of the same wind-wise for the end of the work week. However, winds today will be blowing out of the west-southwest, which will allow highs to climb up a few more degrees. 

Few Evening Showers 

After highs struggled to make it out of the 40s Thursday afternoon, temperatures today should have what it takes to peak in the low to mid 50s. Forecast models then show another quick-moving low pressure system sliding into the northern half of Illinois by this evening. 

Along with this storm system does come the potential for a few scattered showers. I would keep an eye on this shower threat if you plan to attend any high school football games scheduled for this evening. The threat should come to a close quickly, with clouds quickly decreasing shortly. With clear skies overhead, this will bring a better opportunity for frost to develop, especially with temperatures rapidly towards the freezing mark (32°).

Chilly Weekend Ahead:

Despite there being a bit more sunshine in the forecast over the weekend, temperatures remain seasonably chilly in the lower 50s. Another cold front is shown sliding through northern Illinois and southern Wisconsin Sunday morning. Now initially, there won't be much cold air filtering in behind it the frontal passage. But come Monday morning, an even colder shot of air looks to move overhead, resulting in highs in the 40s.

Graupel mixed with rain showers Thursday afternoon

 

Many southern Wisconsin and northern Illinois residents may have experienced something other than rain falling from the skies early Thursday afternoon. It wasn't snow, although wasn't too far from it, and it wasn't hail or sleet. It was actually graupel. Graupel isn't a new weather phenomenon, but it isn't one that we experience all too often either.

A strong, and cold, low-pressure system over the northern Great Lakes will continue to filter in an unseasonably cold air mass across the Midwest. This was felt Thursday afternoon when temperatures stayed in the 40s and wind chills were down in the 30s! Scattered rain showers developed as the cloud cover moved in during the late morning and early afternoon, but it wasn't all rain that occurred. Temperatures were cold enough just a few thousand feet above the surface to allow for the development of graupel. Graupel is different from hail in both the way it forms and looks.

Snowflakes that formed in the clouds way above the surface fell through a layer in the atmosphere where there were supercooled water droplets. These are water droplets that are in an environment where the air temperature is below freezing, but the droplets haven't frozen - they are in a pure form, not freezing onto any dust or other particles in the atmosphere (known as condensation nuclei). When the snowflakes are introduced into this layer the water droplets freeze, or rime, on to the snowflakes forming tiny, white pellets that often times resemble small hail. However, graupel is softer than hail.

The scattered rain showers from earlier in the day have ended, but a chilly rain is set to move in Friday evening. Most of the weekend is looking pretty dry.  

Freezing temperatures Thursday night

 A FREEZE WARNING has been issued for Winnebago, Boone, McHenry, Ogle, Lee and DeKalb counties beginning late Thursday night, lasting through Friday morning. A FROST ADVISORY has been issued for Green, Rock and Walworth counties in southern Wisconsin beginning late Thursday night, lasting through Friday morning. Be sure to cover up, or bring in, anything you would like to protect from the cold.

Skies Thursday afternoon were quick to fill with

cloud cover, holding temperatures in the 40s for much of the day. The gusty west wind even brought wind chills down into the low 40s! We'll hold on to the cloud cover through most of the evening, with skies turning partly cloudy during the overnight. Overnight lows will fall to 30 degrees for most.

A mix of sun and clouds can be expected Friday with high temperatures rising into the mid 50s and southwest/west winds gusting to 25-30 mph during the afternoon. 

Spotty Showers Possible, Gusty Winds Linger

Gusty Stretch As of Late:

I hope you were able to anchor down any inflatable or light weighted Halloween decor before this windy stretch of weather settled in. 

Over the last two days, the Rockford Airport has averaged a peak wind gust of 42mph. Unfortunately, these winds will remain a nuisance moving forward, keeping our temperatures well-below average in the process. 

Spotty Showers Possible:

Thursday begins with some sunshine. But as a quick-moving low pressure swings in from the north-northwest, clouds will gather up into the afternoon. Forecast models keep moisture-levels very low throughout the day. 

However, with air quickly rising in certain parts of the atmosphere, mainly from the newly-introduced pocket of cold air aloft, this could be enough to generate a few spotty afternoon showers. Although the chance is low, one or two of these showers could feature a different type of precipitation, one we call graupel. Graupel is like hail, but soft and can be crushed easily. By no means does this mean we have the potential for severe weather. In fact, it's the complete opposite.

Gusty Stretch Lingers:

In a similar fashion to the past two days, winds will ramp up considerably, reaching 30-35 mph at times. These chilly northwesterly winds will limit highs to the upper 40s and low 50s. With high pressure sliding in overnight, Friday begins on a sun-filled but much cooler note. 

Expect temperatures to be in the upper 20s and low 30s as you step out the door. As the day carries on, skies will turn mostly cloudy, with another opportunity for a sprinkle or two arriving for the afternoon. Once again, winds will be a nuisance, gusting between 25 to 30 mph. This time, however, winds will be blowing from the southwest, which will help our temperatures reach the mid to possibly upper 50s.

Cooling Down Further: 

In the long run, it doesn't look like temperatures will make the climb towards seasonable-levels as we jump into the second half of October. Another cold front looks to sneak through northern Illinois and southern Wisconsin Saturday night into the early stages of Sunday. 

The cooler air that filters in behind it will bring temperatures down into the upper 40s for start of the work week next week. For those that are wondering, the Stateline doesn't see average highs in the upper 40s until November 10th. So yes, this does come a little less than a month ahead of schedule. During this time, we can expect overnight lows to fall into the upper 20s. So, also expect the potential for our first hard freeze early next week.