When does spring officially begin across northern Illinois

First Day of Spring:

We are progressing through what Tom calls the "belly of the beast" as winter is in it's final days, though it has been putting up quite a tough fight. The first day of spring is Friday. It officially begins at 10:46AM and that is the moment when the Earth's tilt allows the sun to shine directly over the equator.  

Amount of Daylight:

This is also the moment when daylight and nighttime are almost perfect balanced, marking the transition towards longer, warmer days across the Northern Hemisphere. After the equinox, our next astronomical milestone is the summer-solstice, also know as the longest day of the calendar year.  

  

Temperature Trend:

Milder air spills into the Stateline for the few days of spring, leaving us with 50s Friday, then closer to the 70-degree mark Saturday afternoon. Precipitation chances over this three day stretch will be highest on Sunday as that is when forecast models show a strong cold front pushing through.   

Light snow chances across northern Illinois taper off early

Scattered Snow Early:

Snow is still falling this morning as a weak storm system moves across the western Great Lakes. While totals have been minor, the snow that has fallen so far has been enough to leave roads in some counties partially covered. Those heading out early will need to give themself extra travel time. 

 

Snow chances should taper off before mid-morning, giving way to dry but partly cloudy conditions for the afternoon hours. The sunshine will give temperatures more of a boost than Tuesday, leaving afternoon highs just short of the 40-degree mark. 

 

  

Another Weak System:

Northwest flow continues to dominate the upper-level pattern, steering another weak disturbance in the direction of northern Illinois. Forecast models remain quite scattered with how much precipitation this system will produce, leaving us with just a chance for a few showers into Thursday morning. 

Light snow Tuesday night could create slippery travel for some

 

Clouds have filled back in Tuesday afternoon and evening ahead of our next clipper system that'll pull a warm front through the area later tonight. As it does, a period of light snow is expected to develop moving in from west to east overnight.

Dry air initially at the surface - surface dew points are in the single digits - will limit any snow from reaching the surface during the evening. But as more moisture eventually begins to saturate the atmosphere, we should start to see the light snow fall. Totals won't be much and most will remain under two inches. Look for the snow to move sometime after 9pm, although a few flurries could arrive a little before that.

The snow will be wrapping up before sunrise Wednesday but there could be a brief period of some freezing drizzle that mixes in before it comes to an end. Even though snowfall amounts will remain minor, when combined with the cold temperatures overnight, and ice/slush already on the roads from Sunday/Monday, we are going to see those slick and icy conditions continue into Wednesday morning. There was quite a bit of black ice Tuesday morning, and I anticipate there to be similar issues for tomorrow morning.

Bitterly cold St. Patrick's Day with additional snow on the way

Hazardous Travel Lingers:

Travel impacts from the latest blizzard continue into our Tuesday morning. As of 4:00AM , roads in a few Stateline counties including Stephenson, Carroll, and DeKalb County remain completely covered in snow and ice, especially in open areas. If you're heading out, be sure to use extra caution. 

  

St. Patrick's Day:

If you plan to celebrate St. Patrick's Day even further, make sure to bundle up. The bitter cold settling in behind Monday's blizzard will make for a harsh start to the day, with wind chills hovering around 10°  below zero. Even by this afternoon, wind chills will only "improve" to about 10°, and high temperatures will struggle to reach the 20° mark. Cloud cover will gradually increase into the evening as our next storm system approaches from the northwest.

Snow Chances Return: 

Forecast models show this weaker system sliding in overnight tonight, bringing the chance for scattered snow showers ahead of Wednesday's morning commute. While this won't be a major storm or compare to Monday's blizzard, it will be enough to lay down widespread 1"-3" totals. Expect slick and potentially slow travel early Wednesday. Overnight lows will briefly drop into the upper teens, then climb back into the 20s by Wednesday morning. 

Scattered light flurries/snow showers continue Monday evening

 

We continue to see scattered snow showers and flurries fly across the skies here in northern Illinois and southern Wisconsin thanks to an upper-level disturbance passing down the western Great Lakes. While this won't amount to much in the snowfall department, it will cause visibility to fall within the narrow, but at times intense, snow bands. Any additional accumulations from these are expected to remain minor, but hazardous travel will be likely through early Tuesday.

On top of the light snow we have coming down, winds are still gusty from time to time from the northwest. This has led to continued blowing and drifting snow, causing snow to blow back over roads and ice over.

Northwest winds will remain gusty around 20 mph through the night and into early Tuesday morning, so icy and slick conditions are likely to continue at least for some of the morning commute.

Winter Weather Advisory replaces Blizzard Warning, Hazardous travel still expected

 

UPDATE: The Winter Weather Advisory has been extended until Midnight for all of our northern Illinois counties.  Blowing snow will reduce visibility down under a mile in many locations, especially the open and rural areas.  Snow covered and slippery road conditions will persist through the night, and most likely into Tuesday morning.

PREVIOUS UPDATE: A Winter Weather Advisory is now in effect for most of southern Wisconsin, with the exception of Walworth County where the Blizzard Warning is still in place, and for northern Illinois until 4pm for Stephenson, Jo Daviess, Carroll, and Whiteside counties in northwest Illinois, as well as for Rock and Green counties in southern Wisconsin. It is in effect until 7pm for Winnebago, Boone, Ogle, Lee, DeKalb and McHenry counties. This replaces the Blizzard Warning that had been in effect for the viewing area.

While most of the accumulating snowfall is done there are still some snow showers falling over portions of southern Wisconsin and northeast Illinois early Monday afternoon. Only minor accumulations are expected from that.

Northwest winds will continue to gust from time to time between 30-40 mph and this combined with the freshly fallen snow will keep blowing and drifting snow a concern through the evening. This will be especially true in the open and rural areas where near ground blizzard/whiteout conditions can be expected. On some of the main interstates and highways the snow has melted, but it is still wet and slushy. And in some open areas there is still blowing snow, at some points covering either one or both of the lanes. You are still going to want to remain cautious throughout the day as slick and, in some areas hazardous, travel remains a concern. Remain alert for quickly changing road conditions through the evening commute.

On roads that are still snow/ice covered they will remain slick through the night and into Tuesday morning as temperatures drop into the single digits tonight and wind chills fall below zero.   

Latest on this morning's blizzard across northern Illinois

Blizzard Update: 

Radar imagery continues to depict the heaviest snow focused along the I-39 corridor as of 4AM. 

Winds are steadily increasing as this storm system moves into and intensifies over the Great Lakes. This will likely result in treacherous and dangerous travel conditions throughout the morning.  

The entire Stateline areas remains under a Blizzard Warning until 1PM this afternoon. 
 

   

Travel Impacts:

Per IDOT and WIDOT, roads across the region are completely snow-covered. During my travels, the roads were completely snow-covered, particularly once outside the city limits.  

 

 

The worst will be during the morning hours, primarily before mid-morning where snowfall rates could be as high as 1" to 1.5" per hour. 

This, along with winds up to 45-55 mph will likely leave visibility under one mile for many, nearing white-out conditions. This will also make blowing and drifting snow a big concern. So PLEASE take it slow if you must be out this morning. 

Snowfall rates will gradually lower as we approach midday, staying below .50" per hour this afternoon. Extra caution is still warranted for those traveling as winds remain quite breezy into the evening commute later today. Snow showers will finally taper off this evening, leaving us with decreasing clouds overnight. This will result in a VERY cold start to our Tuesday, leaving overnight lows in the single digits and wind chills below zero. Values could be as low as -10 degrees. 

Next Snow Chance:  

Models showcase another chance for snow showers arriving late Tuesday into Wednesday. Fortunately, this is a much weaker system so it won't amount to what we are waking up to this morning.