Monday Morning Weather - Updated for Evening

10:45PM Update:

The moderate to heavy steady precipitation has now lifted well to our north into Central Wisconsin. We are now seeing a few light scattered snow showers across portions of Jo Daviess, Stephenson, Carroll, Rock, and Walworth Counties. This will likely continue into the night before winding down late tonight. The good news is additional accumulations look very light, if any at all. The storm system did bring a hefty amount of snow, sleet and freezing rain to a good portion of the Stateline. Here are a few totals:

While the magnitude of these values is not all too impressive, these amounts are very high. The reason is because most of the precipitation that fell today was sleet, or ice pellets. When you talk sleet, amounts usually don't exceed an inch. With this system, plenty of moisture was available, and the vertical temperature profile of the atmosphere was just right to support moderate to heavy sleet throughout the event. Therefore, we were able to get 2-4" of sleet (with some snow mixed in) to accumulate in many areas. Sleet amounts of 1" are significant because it is all ice instead of snow, which is lighter and fluffier. When you start seeing amounts of 2" and 3", it is evident the storm system was very strong. So, while these totals do not initially look impressive, remember that they are representative of sleet with some snow mixed in. Sleet totals like these are not common as you need the perfect set up in order to get sleet to fall for such a long duration of time.

Again, the system is winding down and Winter Storm Warnings will eventually be allowed to expire for the entire region. Roads will continue to be slick and snow/sleet covered through the night with temperatures hovering around freezing. Thus, if you must venture out tonight or very early on Tuesday, make sure to exercise extreme caution.
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8PM Update:

 One more wave of moderate to heavy snow and sleet moving through the region this evening. The snow rates are 1-2" per hour in the heaviest bands, which have been highlighted here. Visibility is below a quarter of a mile at times within the heavy snow, and winds are blowing the snow nearly horizontal this evening. These last remaining bands of snow will continue moving north. Expect the precipitation to become light and scattered after 9-10pm from south to north across the area.

Earlier this evening we had sleet, freezing rain and snow mixing together. Now thru roughly 9-10pm we have heavy snow moving through the region. Winds will continue to be gusty out of the east northeast up to 35mph, but after 10pm, those will subside. After 10pm, the precipitation will turn very light and isolated as the area of low pressure shifts north into Northern Wisconsin. However, with the snow/sleet/freezing rain totals we have thus far, the roads will remain slick, snow-covered, and treacherous through the overnight hours. Therefore, if you don't have to be out, please don't. Many roads are extremely dangerous to be driving on tonight. Give the road crews time to clean them off, and hold off on venturing out until Tuesday, if possible.

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5PM Update: The wintry mix is continuing across the Stateline. It is becoming lighter and more scattered as the moisture moves north. This is the "dry slot" of the storm system. More moisture is filling in to our south, and will stream in this evening in the form of freezing rain and sleet. Some areas to our south will likely remain as plain rain with some freezing rain mixing in. After roughly 9pm, expect precipitation to become much lighter and scattered in nature.

Temperatures will remain around freezing through the evening, but the upper levels will warm slightly, which means freezing rain becomes increasingly likely. The chance of freezing rain through the middle of the evening will allow for minor ice accumulations. This will lead to the potential for more power outages as power lines and tree limbs will likely become glazed in ice. If you combine even minor ice accumulations with winds gusting upwards of 35-50mph, down tree limbs and power lines become more likely.

Current wind gusts are upwards of 30-45mph. These will likely keep up through a majority of the evening. Although precipitation will become much lighter and more scattered after roughly 9pm, temperatures hovering around the freezing mark will keep the roads in bad shape, especially those that are less traveled. Plenty of roads, including US 20 are reporting nearly 75% snow and ice coverage. Therefore, it is highly advised that if you do not absolutely need to travel tonight, that you don't.

Locations shaded in the red and yellow are where current road conditions are poor. That includes the northern third of Illinois. Multiple spin-outs have been reported thus far today, and if you are traveling across Northern Illinois, the risk of more spin-outs remains in place. Road conditions will improve late tonight as road crews get a chance to catch up to the wintry mess because precipitation rates will steadily decrease. Nonetheless, using extreme caution is highly advisable through the night into Tuesday morning. A few pictures have been sent into the Weather Center of the sleet and freezing rain.
Here are a few:

This photo shows two windows covered in ice. This was a common scene across the region today as freezing rain and sleet had no issue sticking to elevated surfaces.






Roadways looked like this throughout the day as sleet, snow and freezing rain came down so heavily, it disallowed the road crews to keep up with it. Roads will continue to be ice covered through the night.

 With the powerful winds, we have seen drifts of sleet, snow and freezing rain upwards of 8-10"! This is from Roscoe. Outside of the station, we have a sleet drift upwards of 9"!






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2PM Update: Moderate to heavy precipitation is continuing to fall across the Stateline. The majority of the precipitation has been sleet, but snow and freezing rain have been mixing in as well. The snow is confined to areas near and north of the Illinois-Wisconsin border. The freezing rain has been just to our south thus far, but with the low pressure center continuing to push northward, warmer air is going to continue to edge its way north. That means the freezing rain will also push north into the region through the afternoon. The good news is this means our ice accumulations will be less than originally thought because we have experienced a longer duration of sleet with the colder air remaining in tact.

However, light ice accumulations up to 0.1-0.2" are still a good possibility, especially along and south of U.S. 20 where slightly warmer air has been present. Regardless of precipitation type, there are power outages being reported now across the region. Southeast Rockford has roughly 1,500 customers without power, according to ComEd. And, any freezing rain we get could cause serious issues in terms of power outages because of the strong winds gusting upwards of 50mph.

Here is a map showing the current power outages across the region. Expect this trend to continue through the afternoon into the evening with winds continuing out of the east and northeast. The other issue we have out there is ice and snow-covered roadways. This includes highways, main thoroughfares, side streets, and parking lots. The precipitation is falling at such a high rate that road crews simply are struggling to keep up. As a result, many roads--if not all--are covered with slush, which is causing accidents. If you must drive, please use extreme caution and slow down.

The City of Rockford has also stated that the Odd-Even Parking Ordinance will go into effect tonight at 7pm. A Winter Storm Warning remains in effect for the entire Stateline. For the counties of Winnebago, Lee, Ogle, DeKalb, McHenry, and Boone, that will expire at 6pm. However, the National Weather Service is considering extending that warnings because wintry weather is expected to last longer than previously thought. For all other counties, that warning goes until Tuesday morning at 6am.

Here is the latest timeline for the storm. Expect sleet, snow and freezing rain to continue to mix across the region with winds gusting to 50mph through the late afternoon. Then, as slightly warmer air in the middle levels of the atmosphere works its way in later this afternoon, we could see more in the way of a freezing rain scenario with some sleet mixing in. In fact, in our far southern areas, freezing rain and plain rain could fall late this afternoon into the evening. Then, expect precipitation to wind down and become much lighter by roughly 7pm. It will end in the southern counties first as the moisture moves from south to north. Through the evening hours, plain rain showers mixed with freezing rain is likely as a quick shot of warmer air moves in, but by this time, the precipitation will be noticeably lighter. A few light snow showers are possible overnight, but nothing significant is expected from that.

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Noon Update: A strong area of low pressure is still tracking through Missouri and is forecasted to lift north over the Stateline through the afternoon. This deepening low pressure system is causing flash flooding through southern portions of  the state, and a wind whipped winter mix for northern Illinois and southern Wisconsin.

Currently we still have light snow mixing in with moderate bands of sleet, though there are some periods of freezing rain as well. So far through the morning we've see mainly sleet accumulate which is somewhat of a good thing, because it means our ice accumulations will be lower.

We will continue to see a freezing rain and sleet mix through the afternoon today and into the early evening as the low continues to get closer to us. This will keep the weatherisk high as we see the potential for ice to accumulate on elevated surfaces such as tree branches and power lines, as well as glazing over roads.

As winds today pick up and gust near 50mph today, widespread power outages are possible. Strong winds will also lower visibilites and have can bring down tree branches because of the added weight.

Overall, watch for ice and sleet covered roads this afternoon and evening as the winter mix continues to fall. Again, we could see near 0.25" of ice accumulate on elevated surfaces through the early evening, before our surface temperatures warm above freezing. Winds will still be breezy overnight, but won't be as strong as what we see this afternoon and early evening.







10am Update: Still tracking the snow/sleet/ and freezing rain this morning. Here are some local reports so far:
 
Marengo,IL: reports of 0.3" inches of sleet so far.
Roscoe, IL: Reports of 0.25" of sleet.
Freeport, IL: 0.10" of  freezing rain in Freeport with 1 inch of snow. Sleet accumulations of 0.50"
Milledgeville, IL 0.10" freezing rain reported and under an inch of snow.
Nora, IL (Jo Daviess): 0.5" snow mixed with sleet







7:45 Update: Band of moderate snow and sleet currently falling in the Rockford area as well as near Poplar Grove and Woodstock
 Patching freezing rain to the south.

Sleet and snow already spreading north into the Stateline - at the station as of 6:30am not noticing any precip falling - but have reports of light snow accumulation and sleet in Rochelle and Esmond according to our weather watchers. Also reports of snow and sleet in Amboy.

Storm Prediction Center released a Mesoscale Discussion about the potential for more freezing rain and winter mix precipitation today. You can see northern Illinois and southern Wisconsin highlighted in the area for a winter mix, including freezing rain, sleet, and snow fall. The greatest potential for freezing rain is nearing 7am through noon with precipitation rates near 0.05" an hour. This means we could see accumulations near .25" of ice. This is because we will have a sufficient warm layer of air up above allowing for any ice to melt and fall as rain, but then refreeze on surfaces as our temperatures at the ground are at or below freezing. Sleet - or ice pellets - are also possible.

Ice accumulations are also possible along the I-80 and I-90 corridors making driving hazardous. You can keep an eye on road conditions here.