More accumulating snow on the way Monday afternoon

 TONIGHT: Fresh snowpack and strong arctic high-pressure systems typically result in VERY quickly falling temperatures. The wrench in that forecast tonight is cloud cover. High clouds have been moving overhead from the West, and it is still to be seen how much of an impact that will have on our temperatures tonight. As of 7PM, a few spots were down into the low 20s. Several locations may end up well into the single digits overnight, but this kind of a forecast has very high boom/bust potential with the clouds. We could end up seeing 10° temperature differences across relatively short areas, depending on how clouds and snow influence the temperature trends tonight. Regardless of how far temperatures fall, melted spots from earlier this afternoon will likely freeze back over, so be very cautious of slick surfaces through tomorrow!

MONDAY: Temperatures will return into the 20s for Monday afternoon, but our next weather system will slide in from the West, bringing another round of some accumulating snow. Snowfall may begin as early as 12PM in some of our Southwestern counties before spreading over the whole area by mid-afternoon. Snow will only last into the late evening of Monday and likely wrap up entirely by midnight.

This will NOT be nearly as impactful as the weekend winter storm, but most locations will see between 1-3" of fresh powder on top of the current snowpack in place. With surface temperatures already cold, anything that falls will stick and likely onto roadways once again.

The good news is this snow will be a much lighter and fluffier snow, with snow ratios closer to 15-20:1, rather than the 11-12:1 we saw Saturday. That means the snow will not have as much liquid contained in it. A winter weather advisory was issued for Whiteside County that will run from 12pm Monday to 12am Tuesday. There is a potential for a narrow band to set up with 3"+ totals near and South of I-88, so Lee and possibly DeKalb County *may* get added onto this advisory.

TUESDAY-ON: We have some ups and downs in the forecast ahead, but Wednesday night through Friday morning will be downright frigid with temperatures likely not getting above the mid-teens Thursday and pushing zero overnight. Any chances for precipitation beyond Monday evening look very slim in nature, but there is a small chance for some light snow or freezing drizzle Wednesday, then another chance for snow Saturday night. Once we get closer to those, we will have more information on how those systems will track.

Sunday morning winter weather recap

 

Snow showers have continued to become more scattered throughout the morning as dry air has gradually filled in behind the low-pressure system that impacted us yesterday. Accumulation totals with these showers is expected to remain lower, however with a larger shower moving in from our north, visibility may drop quickly in spots as snowfall rates may briefly increase. Continue with extra caution this morning if you are heading out especially areas east of Winnebago County.

Over northeast Rockford not a whole lot is going on however it's clear we seen significant snowfall especially in areas with larger drifts. Across Winnebago county snowfall totals range from 6"-8" while areas with drifting snow may have drifts up to two feet tall or more! Drifts will continue today as well with wind gusts up to 25 mph this afternoon.

Across the region, snowfall totals seemed to have lined up very well with the forecast of 6"-10" with even an overperformance possible in some locations. Some locations to pay attention to are areas of Stephenson and Joe Davies counties where a semipermanent band on heavier snowfall setup late yesterday evening which helped some of those areas see higher totals near 10+ inches! Any other snowfall this morning should stay light with only a half inch added on to totals mainly east of Winnebago county. 

Winter storm updates: Tracking the snow and road conditions

 12AM UPDATE: Steady snow still ongoing for much of the Stateline, but the end is in sight across Eastern Iowa. After 2AM, snow will begin to taper off, but wind will be picking up from the Northwest (20-30 mph gusts). Blowing and drifting snow will remain a concern into midday Sunday, especially on open and rural roads. Road conditions should improve greatly by morning as plows are able to keep up with the lighter rates of snow.

9:15PM UPDATE: North of I-88 will likely continue to see steady snow persist beyond midnight. But snow will become more scattered throughout the night as winds pick back up from the Northwest. Blowing and drifting snow will remain a concern into Sunday.

7:15PM UPDATE: Steady to heavy snow continues to push across the Stateline with snow rates near 1"/hour at times. Visibility will remain limited below a mile while the snow is coming down. Some roads are "impassable" in Boone County according to the sheriff's office, so avoid travel if at all possible!

5:40PM UPDATE: Real heavy burst of snow developing along the Stateline in Green/Jo Daviess/Stephenson Counties, moving ENE. Significantly reduced visibility and faster accumulation likely in that pocket over the next hour or two as it moves along the IL/WI state line.

4:20PM UPDATE: Radar is showing a bit of a lull moving into parts of Whiteside and Lee Counties. Additional heavy snow is still expected to move in from the West, so we are not done yet. Snowfall rates up to 1" per hour remain possible through about 7-8PM.

2PM UPDATE: The heaviest snow is moving into Northern Illinois this afternoon, with snowfall rates approaching 1" per hour at times. While snow will not come down this heavy the entire time, the heaviest bands of snow will accumulate much quicker and result in very poor to dangerous travel this afternoon and evening.

Road conditions, per the Illinois and Wisconsin departments of transportation, are reporting "completely snow covered" roads across nearly the entire area. Plows are out and working, but the snow is coming down faster than roads can be cleared. Travel is not advised Saturday afternoon or evening.

Visibility is significantly limited with the falling snow and not helped any by the strong Southeast winds. Visibility is down near a half mile for most in the Stateline, and some down to a quarter mile.

Heaviest snow will persist through about 8PM this evening, with snowfall rates up to 1" per hour. Snow will ease up some after 8PM, but blowing and drifting will remain a concern through the evening and into the night. Snowfall tapers off by 6AM Sunday morning. Winds will flip to come from the Northwest Sunday morning, which will continue the threat for blowing and drifting even after the winter storm warnings expire at 6AM.

Consistent snowfall through Saturday with dangerous travel conditions

 

Snow showers have become more widespread throughout the morning across the state line, as of 12 a.m. light snow began falling in Rockford, but as we head into the 6 o'clock hour heavier snow showers are now visible on satellite and radar. This is best noted by the dark blue color contours pushing into Freeport. Expect snowfall to continue and even become heavier at times as we head into the afternoon.

As heavier snow showers have moved in, snow has begun to gradually start accumulating on both roadways and other surfaces. The main concern will be driving conditions on roadways with slick conidiations becoming worse towards the afternoon as snowfall continues and becomes a bit heavier with time.

As of 5:15 a.m. road conditions have already quickly deteriorated as well even with only light snow being reported through the morning. Take extra precautions on roadways today and try to avoid travel all together if necessary. For more information on roadway conditions, you can visit Illinois Winter Conditions where timely updates are made through the day.

Back onto snowfall, as seen on Satellite and Radar consistent snow showers are already overhead. Snowfall once again will only continue into the afternoon with heavier rates likely towards 1 p.m. today with snowfall rates up to an inch per hour. Snowfall will last through the evening with lighter showers filtering in by midnight tonight. Flurries will still be possible all the way through 4 a.m. tomorrow.

Although we are expecting higher totals between 6"-10" the good news is that we aren't expecting most of this snow to fall in a short time frame. Expect more consistent snowfall with a few hours in the afternoon bringing in slightly higher rates. Through the next 18-24 hours areas may see totals up to 10" while a few isolated spots in Lee County and Northwest Illinois may see slightly higher totals.

Once again, timing everything out snow showers will continue through 8 a.m. this morning. By the late afternoon and early evening, with the low-pressure system approaching, higher moisture content will allow for heavier snow rates up to 1"/hour. This will also be the most dangerous travel time, so at this time travel should be completely avoided. By the evening hours consistent snowfall will continue with most showers tapering off into the overnight hours and into early tomorrow where a few flurries will still be possible.
 

 

 
 

Heavy snow arrives Saturday morning, difficult travel likely

 While Friday was dry and sunny in the Stateline, a winter storm is headed our way, set to bring accumulating snow overnight and throughout all of Saturday. Locally, the Stateline remains dry as of 6PM, but here's what is heading our way! This view from just West of Des Moines, Iowa shows steady snow falling and beginning to stick on main roadways.

Out ahead of this, there is still quite a bit of dry air limiting any precipitation just yet. Even much of Eastern Iowa has yet to see any snow reaching the ground. But as the snow works through the dry air in the low levels, we will begin to see our first flakes reach the ground.

Still looks like snow begins after 12AM for most in the Stateline, with some spots East of I-39 possibly not even seeing initial flakes until after 2-3AM. Snow will begin light at first but will steadily pick up the pace into the early morning hours of Saturday.

By 8-9AM, the heaviest of the snow will be arriving. These heavier bands of snow may be capable of producing up to 1 inch of snow per hour. This will limit visibility and quickly accumulate even on treated surfaces. Southeast wind gusting near 25 miles per hour will cause some blowing and drifting snow as well, only further hampering visibility and travel conditions.

Those heavier bands of snow will persist through the mid-afternoon and even into early evening. At this time, the snow to liquid ratio may be pushing closer to 10:1, which would indicate a slightly heavier and wet snow compared to earlier in the morning. Most intense bands of snow will continue limiting visibility and accumulating on roadways. Winds gusts will remain near 25 mph from the Southeast. Travel is not advised Saturday afternoon. For current road conditions in Illinois, visit Illinois Winter Conditions.

By late evening, snowfall will begin to taper off a bit. Light to steady snow will continue accumulating but not nearly as much as the afternoon window. Most of the snow will then be wrapping up early Sunday morning. But winds will pick up on the back side of this low, flipping things to a Northwest wind for Sunday. More blowing and drifting could remain possible even after the snow has stopped falling.

Below is a recap of all that was written above, highlighting the heaviest snow between 8AM and 5PM Saturday, when snowfall rates may be up to 1" per hour. Travel will remain difficult well into the evening with the continued steady snow and additional blowing and drifting.

Winter storm warnings will go into effect at 12AM for Jo Daviess, Stephenson, Carroll, and Whiteside Counties in Northwestern Illinois and go into effect at 3AM for everyone else. All warnings will run through 6AM Sunday morning. 6-10 inches of snow is still expected area-wide, but regardless of how much snow falls, travel will be very difficult to nearly impossible for much of Saturday. Even the most ambitious snow removal strategies may not be able to keep up with the heavier snow rates, especially Saturday afternoon.

For continued updates, be sure to check back here throughout Saturday for the latest!

All of northern Illinois placed under a Winter Storm Warning

ALERTS: The National Weather Service expanded the WINTER STORM WARNING overnight to now include the remaining Stateline counties. 

For Winnebago, Boone, Ogle, Lee, McHenry, and DeKalb Counties, this will begin tonight at 3AM and last until 6AM Sunday. The same goes for our three counties up in southern Wisconsin.  

TIMELINE: For those Black Friday shopping or are traveling home from the Thanksgiving holiday, you won't have to worry about snow. Today remains dry as high pressure quickly tracks over the region. This will leave us partly cloudy and breezy with afternoon highs peaking around the 30° mark. 

 

   

It's shortly after the midnight hour where forecast models show snow chances arriving. The expectation is for snowfall rates to gradually increase as the day progresses, possibly approaching 1" per hour during the afternoon and evening. This would be the portion of the event where it would probably be best to stay off the roads as traveling will be difficult.

   

HOW MUCH?:

Snow remains steady through Saturday night but will slowly begin to wind down Sunday morning. In terms of snowfall totals, 4" is a lock. I think much of the region will see 6"-10" which is well into winter storm warning criteria. Much of which will accumulate between midday and evening on Saturday.

  

WHAT FOLLOWS?: 

It's then the top weather headline will switch from heavy snow to the next round of bitter cold. Fresh snow has a big impact on temperatures as it prevents the ground from taking in the incoming solar radiation. So, highs will only peak in the upper 20s Sunday with overnight lows dipping into the single-digits. Monday will be even colder with afternoon highs in the teens. Buckle up!  

What kind of snow will we get this weekend?

 To answer the question of what kind of snow we will be seeing, we have to look into snow-to-liquid ratios. A "heavy and wet" snow would be when you get 5-8 inches of snow for 1 inch of liquid precipitation, or a 5:1 ratio. A "typical" or "average" snow is around 10 inches of snow to 1 inch of water. A "dry and fluffy" snow is closer to 15 or 20 inches of snow for 1 inch of water.

Surface and low-level temperatures directly impact the type of snow we see, as colder air cannot hold as much water and therefore results in the drier snows. While temperatures near or even above freezing result in the wetter snow which is typically slushier in nature.

Our surface temperature will likely hug the mid to upper 20s for most of the duration of this snowfall event, so our snow-to-liquid ratio will be in the neighborhood of 10:1 or 15:1. Snow will start out drier at first, turning a bit more watery by Saturday evening, then dry again early Sunday morning as snow wraps up. An average snow-to-liquid ratio for our upcoming snow event this weekend will be close to 12:1, or 12 inches of snow for 1 inch of water.

Much of the Stateline will see around 0.6" to 0.8" of total liquid precipitation. If you multiply the average 0.7" liquid rain by our estimated snow to liquid ratio of 12, you get around 8.4" of potential snow. This falls right in the middle of our forecast range of 6-10" of snow across the Stateline.

Weekend winter storm timeline for Northern Illinois

 ALERTS: Several inches of snow will accumulate this weekend, beginning Friday night. Winter storm alerts have been issued in advance of this system, which will also go into effect Friday night. Jo Daviess, Stephenson, Carroll, and Whiteside Counties are under a Winter Storm Warning, while remaining counties are under a Winter Storm Watch for now. Upgrades to a warning are likely by Friday morning.

TIMELINE: Nearly all of Friday will end up dry, but light snow will begin around or shortly after midnight. Slowly, snow will become heavier through the morning of Saturday. By afternoon and evening, snowfall rates will be approaching 1" per hour at times. Steady snow will continue through Saturday night but slowly wind down through Sunday morning. Wind will then pick up a bit Sunday behind this system, allowing for some degree of blowing and drifting.

TOTALS: Snow accumulations will reach 6-10 inches for most of the area, well into winter storm warning criteria. Much of that will come down between midday and evening on Saturday, so travel is not advised during that time. There is a little uncertainty with the Northern edge of the snow totals, as even a subtle shift Southward may keep some of our Northern counties on the lower side of the range. But point being, travel will be very difficult to nearly impossible Saturday afternoon and evening. Snow winds down Sunday but blowing and drifting may remain a concern into the afternoon and evening.

Winter storm alerts issued ahead of the holiday travel weekend

 WINTER STORM ALERTS have been issued for the entire Stateline, beginning Friday night and running through early Sunday morning. Jo Daviess, Stephenson, Carroll, and Whiteside Counties have already been upgraded to a WINTER STORM WARNING while remaining counties in our area are still under a WINTER STORM WATCH for now.

Much of Friday will begin dry, but snow will move in from the West after 12AM Saturday morning and won't stop until Sunday morning. Initial snow may come down lighter, as dry air works to limit accumulations at first.

By Saturday morning, steady to heavy snow will be possible with snowfall rates nearly 1" per hour at times. This will continue through all of Saturday, making travel very difficult to near impossible. The heaviest of the bands may be confined to Saturday afternoon and evening, but at least a steady snow will persist through the entire day. With the recent cold surface temperatures, snowfall will accumulate very quickly and will be difficult to keep roadways clear.

Drier air will wrap in toward the back edge of the system Sunday morning, winding down the snow after 5-6AM. That is when most of the winter storm alerts are currently scheduled to expire. Though the snow may wrap up by midday Sunday, blowing and drifting may remain possible well into the evening as winds could gust to around 20-25 miles per hour.

Total snowfall from Friday night through Sunday morning will likely be between 6-10" for most in the Stateline. Northern edges of the area in Southern Wisconsin and far NW Illinois may end up on the lower end of that spectrum if the system trends any further South. Further updates will continue to be posted here and on social media accounts, so stay tuned for refined updates!

Although the main attention in terms of weather has been focused on the weekend, the holiday forecast today is looking to be very cool today. Temperatures will stay in the low 30's while gusty winds out of the northwest up to 35 mph will cause wind chills to drop into the teens today. Make sure to bundle up heading to your Thanksgiving plans today!

Now onto this weekend where accumulating snow continues to look more likely by the day. As of this morning, National Weather Service offices throughout the region have issued Winter Storm Watches across the state line highlighting the possibility of 6"+ of snowfall for areas highlighted.

 
Snow showers with this system will move in as early as 3-4 a.m. Saturday morning with initial snow showers mainly being light. However higher snowfall rates will move in by the afternoon with the heaviest snowfall lasting through 9 pm. Saturday night. Expect the worst of travel conditions from 12 a.m. to 12 p.m. on Saturday!

As of now, confidence has continued to increase for the greatest potential of snowfall to make its way over Northern Illinois and Southern Wisconsin. Snowfall totals may continue to change but with consistent snowfall at consistent rates through Saturday widespread and even heavy snowfall may be possible at times.