Another bitterly cold night, snow showers possible this weekend

 Arctic high pressure resulted in some bitterly cold conditions Friday, as morning temperatures started in the teens below zero across the Stateline. We didn't get much warmer for the afternoon, only returning to -7° in the afternoon. The official high temperature will go down as -1°, which was the air temperature at 12AM this morning.

Temperatures began dropping back into the evening, reaching -10° again at 6PM in Rockford. But an increase in cloud cover overnight will not allow temperatures to fall much further for the nighttime, despite the arctic high pressure sitting directly overhead.

The high pressure directly overhead also results in a lighter wind tonight. As a result, wind chills will not be nearly as bitterly cold as the night before. Temperatures will hover around -10° through much of the night with wind chills ranging between -20° and -25°. In these conditions, frostbite is still possible in around 20-30 minutes, so be sure to bundle up if you must be out!

A COLD WEATHER ADVISORY remains in effect for the Stateline through Saturday morning. Wind chills will hover between -20° and -25° throughout the night before rising near zero for Saturday afternoon. While it will remain very cold, the dangerous wind chills will ease up after 9-10AM.

The incoming cloud cover tonight is approaching out ahead of a large-scale winter storm across a large part of the country. Very dry arctic air in place ahead of it will prevent much snow from reaching this far North. That said, a few light snow showers may work their way through the dry arctic air Saturday evening through Sunday morning. Sunday afternoon looks to dry things back out with the next round of higher pressure.

Heavy snowfall accumulations will be relegated to areas downstate with the better moisture. Areas most favored for fluffy snow accumulations of 1-2" is along I-88 and out toward Chicago. Southern Wisconsin and far NW Illinois may end up completely dry or at most only pick up a half inch of snow. That said, any snow that does fall will stick to the surface and cause slick spots since road treatments will not be as effective with the bitter cold in place. Air temperatures will remain in the single digits or lower until Sunday afternoon.

Dangerously cold Friday, frostbite possible within 10 minutes

The core of this frigidly cold Arctic air has arrived and it has left us below zero in both the temperature and wind chill departments. 

All Stateline counties are now under an EXTREME COLD WARNING until midday as wind chill values could be as low as -40°. Currently, we have Galena reporting a wind chill of -40° with Monroe and Janesville coming in at -33°. 

Please do everything you can from being outdoors this morning as it will only take minutes for signs of frostbite to occur on any exposed skin. Knowing the signs will also be very important. 

 

 

  

After midday, we will be placed under a COLD WEATHER ADVISORY as we can expect wind chills during the afternoon and overnight hours to remain near or below -20°. Frostbite time in that type of cold could occur within 30 minutes. 

This advisory will run until 9AM Saturday morning. Wind chills Saturday afternoon won't be nearly as terrible, landing in the -5° to 5° range.  

As of this moment, this frigid cold is expected to linger into the end of the weekend and into the start of the new work week. One, we have a potent winter storm passing to our south late Saturday night into the first half of Sunday. We may need to watch this system as any northerly shift in the track will increase our chance for snow showers. 

Second, forecast models show a potent cold front passing through late Monday night into Tuesday morning. Both systems will likely leave overnight lows below average, leaving us below zero Saturday night and Sunday. It won't be until Monday night and Tuesday night overnight lows climb above zero.  

Increasing potential for some weekend snow showers

 Immediately behind our large rush of arctic air and dangerous cold, a widespread winter storm will slide across the Central and Eastern United States. This will bring a very large swath of heavy snow, sleet, freezing rain, and bitter cold across much of the country. With our arctic high pressure in place in Northern Illinois, the bulk of the precipitation will remain off to our South. But trends have been subtly pulling the Northern edge of this snow our direction over the last few days.

Winter storm alerts stretch from Western New Mexico all the way up into the Northeastern part of the Country, nearly 2000 miles from one end to the other! Winter storm watches are being converted over to warnings as confidence increases on the potential for accumulating or heavy snowfall. A few ice storm warnings have been issues for parts of the Southeast, including Northern Mississippi for the potential for an inch of ice accretion.

While nearly all of the snow will end up South, we will see the potential for at least a few snow showers creep toward the Stateline Saturday afternoon into Sunday morning. Any snow showers we see this far North will be lighter in nature, and some in Northwestern Illinois or Southern Wisconsin may remain completely dry. But given the bitterly cold air in place, any snow that does come down will stick to the surfaces and cause slick conditions. Road treatments will not be as effective with temperatures remaining in the single digits or lower through Sunday morning.

Gusty winds continue Thursday evening, Temperatures tumble as strong cold front moves through

 

Winds were quick to increase Wednesday night with the arrival of our first Arctic cold front that brought bouts of heavier snow, and even a few snow squalls, across northern Illinois and southern Wisconsin. The snow didn't last all night, but the gusty west winds did. This created hazardous travel on some of the local roads as significant blowing and drifting snow became a concern, especially in the open and rural areas. While the strongest of the wind ended early Thursday morning, wind gusts of 25 to 30 mph continued for much of the afternoon. This continued to cause snow to blow across north/south roads.

The wind won't ease much Thursday night with the arrival of the second Arctic cold front, which will keep wind gusts close to 30 mph overnight. Blowing and drifting snow will remain possible in the more open and rural areas through Friday morning. The difference with tonight is that temperatures will be falling, dropping below zero by 10pm and then well below zero by sunrise Friday.

The coldest air will settle in after sunrise Friday with the overnight low forecast to fall between -10 to -15 degrees, but wind chills will range between -30 and -40 degrees. Afternoon temperatures, despite the sunshine, won't rise above zero which will keep afternoon chills in the -20 to -25 degrees. An EXTREME COLD WARNING will go into effect late Thursday night and run through mid-day Friday. After that there will be a COLD WEATHER ADVISORY that goes into effect for the remainder of Friday, lasting into Saturday morning.

Extreme Cold Warning expanded to include all of northern Illinois

ALERTS: Overnight, the National Weather Service expanded the Extreme Cold Warning to now include all of northern Illinois and southern Wisconsin. This will be in place Friday from 3AM-12PM. 

 

  

TIMING: It's during that time where we'll feel the worst of the incoming blast of Arctic air. Overnight lows temperatures will fall well below zero, likely landing in the -10° to -15° range. 

When you factor in a gusty and cold northwest wind, wind chills will likely be in the -30° to -40° range. Frostbite in this type of cold can occur within 10 minutes and is very dangerous to be out in - even if for a short duration of time. Temperatures Friday afternoon will struggle to warm above 0°, with the current forecast 'high' of -5°. Wind chills during the afternoon will sit between -15° to -25° which is still considered dangerous considering frostbite can occur within 30 minutes. The Arctic high-pressure system will settle in a bit closer to the region Friday night, and this should help in our wind chill department some, but chills still as low as -25 are possible Saturday morning. 

Extended Forecast: The coldest air of the season will slowly filter out as we get into next week. Still, we can expect overnight lows to drop below zero at least into Monday morning. Highs next week will make the climb back into the teens. 
 

 

Dangerous cold settles into northern Illinois and southern Wisconsin Thursday night

 

Now that most of the snow is done for the Stateline our focus will shift to the arctic air mass that is set to move in behind our second cold front Thursday afternoon. Temperatures ahead of the front will warm into the upper teens and low 20s during the first half of the afternoon, but then quickly begin to fall as the front sweeps through. This will take place from west to east after 3pm/4pm. Temperatures will quickly fall into the teens, then single digits, and eventually below zero all by 9pm/10pm. To go along with the drop in air temperature, wind chills will also fall well below zero Thursday night. Overnight lows will sit between -10 and -15 degrees across the Stateline, but wind chills are likely to drop between -30 and -40 degrees.

Due to the anticipated cold, there is an Extreme Cold Watch that'll go into effect for northern Illinois beginning Thursday night and an Extreme Cold Warning for southern Wisconsin. We'll likely see the watch changed to a warning by Thursday.

Frostbite in this type of cold can occur within 10 minutes and is dangerous to be out in - even if for a short duration of time. Temperatures Friday afternoon will struggle to warm above zero degrees, with the current forecast 'high' of -5. Wind chills during the afternoon will sit between -15 to -20.

The Arctic high-pressure system will settle in a little closer to the region Friday night, and this should help in our wind chill department some, but chills still as low as -25 are possible Saturday morning. By Saturday afternoon temperatures may be able to inch a little bit above zero with afternoon chills coming up as well, but still below zero for most.

  

Wind-whipped snow showers Wednesday evening

 

The snow from Tuesday night came to an end early Wednesday morning with roughly 1-4 inches falling across far northern Illinois, centered along the Highway 20 corridor and into southern Wisconsin. Areas to the south experienced little to no snow accumulation.

While there is a little break in the wintry weather Wednesday afternoon, snow showers will soon return during the evening with the first of two, Arctic cold fronts that are forecast to sweep across the Midwest and Great Lakes. Light snow has been falling out west over Iowa and Minnesota ahead of a strong cold front that'll move across northern Illinois and southern Wisconsin later this evening. As it moves towards the Mississippi River, we should start to see the beginning of the light snow move in from west to east around 5pm, exiting the viewing area around 9pm.

The snow won't be much, generally around a half an inch to an inch, but an increasing west wind behind the front will cause what snow is coming down, and whatever snow is already on the ground, to blow and drift. In open and rural areas, the blowing and drifting will become rather significant with wind gusts near 45 mph in some locations.

In anticipation of the incoming snow and wind a WINTER WEATHER ADVISORY has been issued for the following counties beginning at 5pm: Jo Daviess, Stephenson, and Carroll in northwest Illinois and Green in southwest Wisconsin. While an advisory has not been issued area-wide, blowing and drifting snow will be an issue all across northern Illinois and southern Wisconsin, even in locations that didn't receive much snow from Tuesday night. 

This will cause hazardous travel through the late evening, with some of those impacts lasting into Thursday morning - even though the winds won't be as strong. North/south roads will be impacted the greatest with the blowing and drifting due to the west wind. Please travel with caution later this evening as road conditions will deteriorate once the snow moves in and winds pick up.