Sunday morning weather update

 

Over the next 24 hours a strong low-pressure system will through the Midwest and Upper Great Lakes bringing multiple impacts to different regions. Some areas are already experiencing heavy snowfall this morning, however here across the state line we'll be expecting not only snow, but rain/thunderstorms, and possible blizzard like conditions into tomorrow morning.

Initially through the morning and early afternoon today multiple rounds of both showers and possible thunderstorms will move through the region. This will be on the warmer side of the low-pressure system as our temperatures will be in the mid 50's. If we build some instability this afternoon, a few rumbles of thunder will be possible however even without instability, rain showers will pack a punch today with any shower carrying the potential of wind gusts between 40-50 mph. If thunderstorms do develop as well (likely past 12 p.m.) an isolated severe thunderstorm can't be ruled out with the main risk being damaging wind gusts (60+ mph).

By the late afternoon and into early evening we'll see the cold front with this system quickly approach which will plummet our temperatures this evening. As this happens a bit of dry air at the surface may give us a brief break in precipitation, however if we keep some moisture around some mixed precipitation may begin to fall near 7-9 p.m. Once we cool our temperatures enough though, we'll expect heavy snowfall at times through the overnight hours combining that with wind gusts over 40 mph.

Most of our winter weather alerts into this evening are focused on the time period beyond our switch to mix precipitation later. As we switch over to snowfall wind gusts will remain in excess of 40 mph while heavy snowfall may amount to 2-6" here across the state line while areas to the north and west may see locally higher totals near 4-8". Because of this, most of the region is under Winter Storm Watches/Warnings (excluding Dekalb and McHenry Counties) including Blizzard Warnings for Stephenson, Jo Davies, Whiteside, and Carroll counties as heavy snowfall and strong winds will promote blowing and drifting snow leading to reduced visibility into the overnight hours.

As we switch over to snow this evening, visibility will quickly drop through the nighttime. As our heaviest snow is falling our wind gusts will also begin to peak with wind gusts through the overnight hours potentially reaching 50+ mph. This will significantly impact both visibility and driving conditions with visibility expected to drop near 1/4 mile at times. If you do plan on driving overnight or tomorrow morning, take things extremely cautious and allow plenty of extra time for travel.

Now in terms of snowfall totals this won't be the primary focus of the system as both the heavy snowfall and strong wind gusts promoting reduced visibility will certainly be the biggest impact from this system. However, most of the region can expect 2-6" of snowfall while areas near and north of Jo Davies County may see local totals of 6" or more. It's certainly going to be an interesting and active 24 hours! Make sure to stay in tune with the changing forecast during this time. 
 
 

Dynamic weather system brings storm threat, blizzard conditions in less than 24 hours

 11PM HEADLINE UPDATE: Green and Rock Counties in Southern Wisconsin were upgraded to a Winter Storm Warning, while Walworth County was converted over to a Winter Weather Advisory. Higher snowfall accumulations will be expected further West, leading to more significant winter impacts. Blowing and drifting snow remains a concern across the map, regardless of how much snow actually falls.

Dynamic weather system brings storm threat, blizzard conditions in less than 24 hours Sunday into Monday: General impacts of this system remain unchanged, but the headlines have been updated, including a BLIZZARD WARNING for Northwestern Illinois. Below is a timeline highlighting the precipitation types and winds expected through the duration of this storm system.

It is still looking like we will see rain and a few storms through the morning and afternoon on Sunday, with an isolated severe risk for a storm or two to produce wind gusts in excess of 60 mph. Outside of storms, winds will be gusting between 30-40 mph through the afternoon.

Sunday afternoon and evening will begin the transition over to freezing precipitation, and it will be a rather quick transition. We may see a period of heavy sleet during this time as well. Northwestern parts of the area may flip over to sleet as early as 5PM, while further South and East don't change over until 7-8PM.

Everyone is fully in the snow machine by 10PM-12AM, with some very heavy snow shortly after snow begins through early Monday morning. North-Northwest wind gusts during this time will be increasing further, pushing near 40-50 mph at times, and possibly higher for some of the Western counties. That will significantly reduce visibility, likely below a mile and at times, below a half mile. Near white-out conditions possible. The worst time for travel will be between 10PM-6AM Monday.

Snow showers will ease up through mid-day Monday, ending by late afternoon or evening. Blowing and drifting snow will remain a concern into the afternoon as winds remain strong gradually shifting to the NW at 40-50 mph.

Jo Daiviess, Stephenson, Carroll, and Whiteside Counties in NW Illinois have been upgraded to a BLIZZARD WARNING that will run Sunday evening through Monday afternoon. Southern Wisconsin and North-Central Illinois remain under the WINTER STORM WATCH that also runs Sunday into Monday (times vary).

Most of the area will see between 2-6" of snow, with the higher end of those totals North and West of Rockford. But even 2" of snow will blow and drift around significantly with these winds, so we continue to emphasize impacts over totals. Open roads may become hazardous to impassable Sunday night through Monday morning, so be sure to plan travel around that potential. The Monday morning commute will likely be significantly impacted. Continue to stay tuned for updates throughout the day tomorrow and stay safe everyone!

Impactful system likely Sunday, bringing the chance of storms, snow, and strong wind gusts

 

In the next 24 hours an impactful low-pressure system is expected to move through the Eastern half of the United States bringing multiple impacts to different regions. Here across the state line, we'll see almost every impact from this system as we'll experience both the warm and cold side of this system.

Early on through the early afternoon and evening tomorrow, a southerly wind ahead of this system will transport warm and moist air allowing for showers, however if we see minor instability develop a few thunderstorms (isolated severe storms) may be possible. As of now, the Storm Prediction Center has outlined most of the region in a 1/5 risk through the afternoon tomorrow for the possibility of damaging wind gusts if proper instability develops.

As we flip onto the cold side of the system the brunt of the impacts will begin to be felt. As temperatures drop tomorrow evening, we may see some mixed precipitation or sleet which will gradually transition into snow showers overnight Sunday and into Monday. The National Weather Service has issued a Winter Storm Watch for the entire region (besides McHenry and Dekalb counties) highlighting the chance for snow accumulation 4 inches or more, along with gusty winds which may promote blizzard like conditions Sunday and into Monday. 

The wind with this system will most likely be the biggest impact especially on the cooler side of the system. Initially our southerly wind through Sunday afternoon will help fuel our storm potential, however wind gusts will still be in excess of 30-35+ mph. Once we flip to the cooler side, wind gusts will peak up to 40+ mph as winds shift out of the north. As this occurs, snowfall will likely be ongoing, or snow may be on the ground so the risk of blowing snow and blizzard like conditions will be possible Sunday evening into Monday morning.

In terms of total snowfall, we are still a bit a way out from knowing concrete totals. However, at least 2-6" do look likely across the region. The wider range takes into account any freezing rain or sleet we see before we switch to snow as any other types of precipitation may eat at our totals a little bit. Even though we're expecting late season snowfall, it could be worse! Folks in Northern Wisconsin are expecting near 1 to 2 feet of snowfall with this system!
 

From storms to heavy snow: Timing out Sunday's wild weather

 From rain and storms to snow and white-out conditions: we could be in store for all of the above Sunday. Yet another strengthening low pressure system will slide our way late this weekend, first bringing the potential for heavy rain and storms Sunday morning. Heavy snow will be likely across Central and Northern Wisconsin throughout Sunday morning.

There will be some pockets of dry time between waves of rain Sunday morning, allowing temperatures to reach into the mid-50s. This sets the stage for some strong storms, however. Dynamics in the atmosphere are strong enough that even a sliver of storm energy locally may produce strong to severe storms with damaging wind gusts as the main threat. A Level 1/5 Marginal risk from the Storm Prediction Center already reaches up to most of the Stateline with a rare Day 3 Enhanced risk downstate and in parts of Indiana.

Pockets of rain with a few embedded storms remain possible through the afternoon, but colder air will quickly filter in behind the passing low pressure system. Most in the Stateline will flip over to a wintry mix between 6-10PM, with a quicker transition across Southern Wisconsin and Northwestern Illinois. The pink color indicates where we could see some very heavy sleet as well. A few rumbles of thunder cannot be ruled out during this time either, as the Southern end of this precipitation field will likely be producing a damaging squall line of storms in Central Illinois into Indiana Sunday evening and Sunday night.

Once we get beyond 10PM-12AM, all the Stateline will be likely seeing all snow as the precipitation type. This also comes with some stronger winds from the Northwest, possibly gusting to 45 mph at times. That will lead to extremely limited visibility and possibly near white-out conditions at times early Monday morning. Scattered snow showers will gradually taper off through Monday afternoon, but blowing and drifting snow remains a concern through the evening.

A broken down timeline shows the windows for different precipitation Sunday. Sunday morning and afternoon will bring pockets of heavy rain with some embedded storms and a risk for some damaging winds. Sunday evening will begin the switch to a wintry mix, including the potential for heavy sleet in the evening then heavy snow after 10PM-12AM. Visibility will be extremely reduced once precipitation flips over to snow. Monday keeps the wind and resulting blowing snow, but new snow will wind down.

Still a bit too early for snow totals, but sleet and rain on the Southern edge of this storm will eat into forecast totals quite a bit. I advise not to take extreme model totals you see on social media as gospel and continue to remain focused on impacts over totals. Rain quickly flipping to a mix and snow with plummeting temperatures will lead to poor road conditions. Regardless of how much snow comes down, white-out conditions Sunday night will result in hazardous travel through at least Monday morning.

A winter storm watch is already out for Southern Wisconsin and Northwestern Illinois for this potential of hazardous travel. Winter storm warnings are in effect for much of Minnesota, Wisconsin, and Michigan's U.P. Be sure to make plans around this impactful system and avoid traveling Sunday night or early Monday if you can avoid it. Monday afternoon will see conditions slowly improve, but blowing and drifting snow will remain possible through the evening. Stay tuned for forecast updates, including potential snowfall totals as the forecast becomes clearer!

Winter Storm Watch expanded into northern Illinois

Winter Storm Watch:

With a secondary system schedule to arrive over the weekend, the National Weather Service expanded the WINTER STORM WATCH to include Jo-Daviess, Stephenson, Carroll, and Whiteside Counties.  

 

  

Timing Out the Precipitation: 

Forecast models show precipitation starting around Saturday evening and Saturday night, staring off light as a scattered mix of rain and snow. By Sunday morning, better moisture will have arrived with much milder air. This, along with temperatures surging into the low 50s will flips things over to all rain.

 

As the low-pressure system moves through, colder air will quickly spill in from the northwest, changing any precipitation to a heavier wintry mix and eventually to moderate to heavy snow. Snow will gradually taper off through Monday afternoon.  

Like the storm system that is passing through today, Sunday's will bring strong winds with frequent gusts of 35 to 45 mph on the table. Winds will blow from the south and southeast Sunday before shifting to the northwest Sunday evening into Sunday night. This will leave temperatures in the 20s for Monday and St. Patrick's Day. 

Highest potential for snowfall accumulations remains in areas to the north of the Illinois/Wisconsin border, mainly up in northern half of Wisconsin and in the upper peninsula of Michigan. 
 

High Wind Warning: Hazardous travel and power outages expected

High Wind Warning: 

You'll want to hold onto everything this morning as these winds are quite intense. Several locales across the Stateline have already observed gusts over 50 mph, including a 58 mph gust in Janesville and a 52 mph gust in Rockford. Because this trend is set to spill into the afternoon, all counties will remain under a HIGH WIND WARNING until 4PM. 

Timing Out the Winds: 

The strongest winds of the day - frequently gusting between 50 and 60 mph - are expected to occur this morning as a fast-moving clipper system to our north pulls a cold front through the region. This will tighten the pressure gradient at the surface, allowing west to northwest winds to remain intense. 

 

Impacts: 

Expect a wide range of impacts - including power outages and difficult travel. Winds this strong will be able to snap tree limbs and put extra stress on power lines, resulting in scattered power outages. 

Traveling will be rather challenging, especially for those who operate a high-profile vehicle as strong crosswinds can make it difficult to maintain control on open stretches of road. 

Lastly, loose outdoor items may be blown around and minor property damage is possible as the strongest winds move through.  Winds will gradually ease through the late afternoon and evening as the clipper system pulls away and the pressure gradient unwinds. By tonight, conditions will end up noticeably calmer, with temperatures falling into the upper 20s.

Increasing potential for heavy snow in Wisconsin Sunday into Monday

 A strong winter storm will impact the upper Midwest and Great Lakes Sunday into Monday, bringing the potential for some very heavy snowfall. Locally, we will see the potential for liquid rain, a mix of sleet and snow, then all snow through the course of Sunday into Monday.

Precipitation will begin Saturday evening and Saturday night in a lighter fashion as mix of mainly rain and snow. By Sunday morning, better moisture will have arrived with much milder air. This flips things over to all rain through much of Sunday.

Once the low pressure system passes by, colder air will quickly work in from the Northwest. This will flip things over to a heavy mix and eventually heavy snow. Snow will then taper off through Monday afternoon. The passing system will also come with strong winds frequently gusting to 30-40 mph. Winds will be from the Southeast through Sunday afternoon, then flip to the Northwest Sunday evening/night. Once snow begins to fall, visibility will be greatly reduced.

While far too early to discuss exact snowfall totals, it looks increasingly likely that parts of Central and Northern Wisconsin may be able to pick up 8" or more snowfall Sunday into Monday with blizzard conditions possible at times. The exact axis of the heaviest snow will be determined by the track of the low pressure itself, with a sharp gradient of little to no snow on the Southern edge of the storm dominated by wintry mix or rain.

A winter storm watch has already been issued for nearly all of Wisconsin for that potential for heavy snow Sunday into Monday. This watch extends all the way to the Illinois/Wisconsin state line, but confidence on winter storm conditions is not quite high enough yet for a watch locally.