Saturday, February 13, 2016

A White Valentine's Day in Store

Instead of pink and red, we will be seeing a white Valentine's Day this year courtesy of a storm system currently getting its act together in the Northern Plains and Upper Midwest. Our current radar as of 8 PM shows a band of snow already stretching from Souix Falls, South Dakota to Des Moines, Iowa to Southern Illinois. The atmosphere is still relatively dry over the Stateline, which is why the clouds are having a tough time moving into the region. However, as we head through the night and into Sunday morning, the atmosphere will slowly saturate. As a result, clouds will thicken tonight and light snow showers are possible as early as 4-6 AM Sunday morning.

The bulk of the snow will fall from late morning into early evening. During this time, the snow will be light to moderate at times, and it should be falling at a relatively constant rate. With winds picking up during the day, blowing snow and reduced visibility could be an issue at times.

A Winter Weather Advisory is in effect for DeKalb, Winnebago, Boone, Lee, and Ogle Counties from 9 AM to midnight Sunday. The advisory is in effect for Rock and Green Counties from 6 AM until 9 PM. The advisory is effective for Jo Daviess, Carroll, Whiteside, and Stephenson Counties from 3 AM to 6 PM Sunday. The reason behind the differing times is due to when the snow is expected to move in and move out.

In terms of accumulations, models are in pretty good agreement with a general 2-4" across much of the viewing area. However, with the snow expected to fluffy and light, totals could be more in the 3-5" range, especially to the south and west of Rockford. Areas to the east, such as McHenry, Walworth and Belvidere could see 1-3" with 4" not impossible.

Friday, February 12, 2016

Wind Chill Advisory

Get ready for some of the coldest air of the season. After a weak system cleared the region Friday, fresh arctic air has nothing preventing it from pivoting into the Midwest. Combine the intrusion of frigid air with some blustery northwesterly winds, and you have a perfect recipe for dangerously cold wind chill temperatures. In fact, the National Weather Service has placed the entire viewing area under a Wind Chill Advisory from midnight until 9 AM Saturday morning. These are issued when wind chills are expected to be at dangerous levels, and tonight's forecast meets that criteria.
As of 7 PM Friday evening, wind chill numbers are already in the single digits below zero to as cold as -10° in Galena. From this point, things will just continue to get colder through Saturday morning as wind continue to be blustery overnight. It is going to be one of those nights where you want to add blankets to the bed and crank the heat up. By the time we wake up on Saturday morning, wind chills could be flirting with -20°. Those are potentially dangerous levels, and shouldn't be taken lightly.

The good news with this arctic outbreak is that it will be short-lived. Temperatures will again fall into the single digits Saturday night, but that will be the last time for the foreseeable future. A moderating trend is expected next week across Northern Illinois and Southern Wisconsin -- in fact, the entire Upper Midwest will see milder temperatures heading into next week. Before we get there, we have to deal with the extreme cold. And, with cold of this magnitude being somewhat rare, it is important to remember a few things:

Valentine's Day Weekend Outlook

We get a mix of winter weather as we head into the holiday weekend. Today will be one of the more quiet days with a few morning flurries and a quick burst of snow, but we won't see any accumulations. The morning clouds will decrease as a strong Canadian high builds in. This will bring in dry but cold Canadian air. Temperatures today will still climb into the lower 20's but tonight you will really feel the chill. As that air filters in, temperatures tonight will drop to the single digits below zero. Along with the cold temperatures, winds will pick up behind our departing cold front and low pressure system. This happens because of a tight pressure gradient (or difference in pressure) between the departing low and incoming high pressure. Winds will gust from the north-northwest up to 35 mph.

 With gusty winds and subzero temperatures, wind chills will fall as low as about -25°. This is cold enough for advisory criteria, and a Wind Chill Advisory has been issued for the entire Stateline area in effect tonight through tomorrow morning at 9am. If you have to be outside wear layers and cover your hands and head with mittens, coat, and a hat! Frost bite and hypothermia can occur in a short period of time with chills that low.

It will still be cold on Saturday, blustery conditions but we have a lot of sunshine. Northwest winds will stay gusty into the afternoon. Highs will make it to about 12 degrees Saturday afternoon. Clouds will increase going into Saturday evening, but it will still be very cold with temperatures close to 2°. You'll still need to bundle up if you're planning to head out to celebrate Valentine's Day.

A warm front gets closer to us on Valentine's Day Sunday, temperatures will warm into the lower 20's. However, with the front inching closer, we will bring in just enough lift to squeeze out some snow. There isn't much moisture to work with but we will have enough lift to allow snow to accumulate. The snow will be light and fluffy because of the dry nature, which will allow it to accumulate quickly. We could see a few inches of snow accumulate for your Sunday, so it's the perfect day to stay in and spend time with loved ones!

The snow will end for Sunday evening and Monday morning, so your commute will be on the dry side. Temperatures then continue to warm up into the 30's next week.

Thursday, February 11, 2016

Accumulating Snowfall Likely Sunday

If it's going to be cold, it might as well snow.  Light snow west of Northern Illinois Thursday evening will mostly miss the Stateline, but a few flurries are possible overnight into Friday morning.

Wind chills as low as -25 degrees will greet you Saturday morning with snow to likely round out the weekend.  And that snow will come with an area of low pressure that will move across the Midwest Saturday night and into Northern Illinois and Southern Wisconsin by Sunday morning.

Moisture will be somewhat limited due to the dry air in place from a departing Arctic high pressure system Saturday.  But as the low moves closer Sunday, light snow is expected to begin as early as late morning and continue into the afternoon.  It may be just enough to have to get the shovels out as a couple inches could fall by Sunday night. 

The low should be out of here by next Monday morning, but another clipper looks to move in Tuesday night and could bring a little more snowfall by Wednesday morning. 

Average First Dates

Despite the bitter cold wind chills that will arrive for the start of the weekend, there is a bit of light at the end of the tunnel. Next week temperatures begin to rise as our jet stream winds lift northward allowing warmer air to filter in. But when we look at our 'average first dates' in terms of those bigger temperature milestones...well...we aren't too far away.

On average, the first 50° gets here by February 9th, which was just a couple of days ago. Unfortunately, we won't be seeing warmth like that in the next week. The earliest we've seen a 50°day was back in 2005 on January 2nd. The longest we've had to wait? All the way to March 31st, but this was in 1912.

The next bigger milestone, 60°, gets here normally in March. The 10th to be exact. The earliest recorded 60° was also in January, the 4th in 2007.

And one of my personal favorite temperatures, 70°. We normally see this April first, though in 2000 we got lucky and saw this arrive February 25th. 

Maybe if we all think warmer thoughts we'll get to 70° a little sooner?

Wednesday, February 10, 2016

Reminder: Storm Spotter Training Classes to Start Soon

With temperatures in the teens, it's hard to switch our mind to severe weather season.  But it will be here before we know it.

If you're interested in learning more about how to become a trained National Weather Service storm spotter, classes are just right around the corner.

The first class for Northern Illinois kicks of Thursday, February 11th, at the DeKalb Police Department in DeKalb County.  This one you do have to RSVP for.  When thinking about attending a storm spotting class, you want to try to attend one that's either taking place in your county or is closest to you.

The next spotter class following Thursday is March 1st in Winnebago County.  For a complete list of classes in all surrounding counties, click on the following links below:

Counties: Winnebago, Boone, McHenry, Ogle, Lee & DeKalb

Counties: Stephenson, Jo Daviess, Carroll & Whiteside

Counties: Green, Rock & Walworth (Southern Wisconsin)

Bitter Cold Wind Chills to Kick Off the Weekend

A weak area of low pressure will move to the southwest of Rockford late Thursday night and early Friday morning, bringing a few light snow showers over Iowa and West-Central Illinois.  Some of those light snow flurries could reach as far north as Northern Illinois early Friday morning, but the afternoon will be dry.

Following the low, a very cold air mass will slide in from the North on the heels of a strong Arctic high pressure system.  Winds will increase through the afternoon and evening Friday and stay gusty into the first half of Saturday.

The cold will push overnight lows Friday close to, if not below, zero degrees.  Wind chills, however, could fall as low as -25 degrees!  That would be nearing Wind Chill Advisory criteria.  We'll see sun Saturday, but clouds will increase ahead of light snow that's expected to fall Sunday.  You can read more on that in the post below.