How Much Snow is Coming?

Monday's snow could be one of the heaviest of the season.  Of course, we've seen a lot of snow this season, but we've gotten it mostly in small, persistent doses.  Take a look a the top five snow systems we've gotten officially in Rockford, and you can see we've only have one event larger than 6". Monday could be our second.  Winter weather advisories are in effect from 6am through 6pm Monday evening.

Monday snowfall forecast

TIMING: There may be some rogue flurries overnight, but more widespread snow starts around the morning commute with heaviest showers picking up around lunchtime til around 3pm.  Some lighter snow showers may impact the Stateline til the evening commute before settling down for the rest of the night.  Snow totals will range anywhere from 3-6". - MT

UPDATE: Greater Certainty in Monday's Wintry System

General thinking as of Saturday evening

On Friday, computer models were indicating that we could see some freezing rain around the area on Monday.  However, the general consensus with the models is now leaning towards pure snow, pushing the freezing rain into central Illinois This is good news for us as just a little freezing rain can wreak havoc for drivers and virtually shut down some communities.  We can handle snow!

Monday, temps will hover around the freezing mark throughout the day meaning that our snow will be very wet and heavy.  Since we are fairly close to the center of the low pressure, where the core of the moisture is, we could also see a significant amount of it.  At this point it looks like we'll see around 3-5" but we'll continue to tweak the numbers on Sunday. - MT

Potential Winter Mess On Monday?

That's the big question right now, but we won't know the exact answer until later this weekend.

Monday's storm system will bring some precipitation with it, but temperatures both on the ground and aloft will dictate whether we get snow, rain, ice, or some combination of the three. Here's what we look at when making our forecast:

When precip forms, it always begins as ice crystals. What determines precip type is the presence and location of temps above freezing between the clouds and the ground. The chart to the right does a great job of showing how rain, freezing rain, sleet and snow all form.

Here's where the challenge in forecasting this storm comes in. Most of the models have us extremely close to the freezing line aloft and ground temperatures just above freezing on Monday. A change of a few degrees could mean the difference between nothing but snow and a wintry mix complete with freezing rain.

That being said, the current forecast is subject to change. We'll call for a rain/snow mix on Monday with accumulating snow and the potential for some freezing rain and sleet. We won't know how much snow until we figure out if we get any rain or ice. Meteorologist Max Tsaparis will have updates as we go through the weekend. Just be prepared for a potentially messy Monday morning commute! -BA

Warmer temperatures may not always be a good thing

A brief pattern change next week will allow temperatures to be considerably warmer than where we've been for the past several weeks, but it could come with a cost.

Temperatures through the end of the weekend will remain below average.  Warmer than they have been, but still below average.  It won't be until next week when the highs will climb back into the middle and upper 30's.  Unfortunately, there will be a few systems worth watching during the Wednesday through Friday time frame that could bring rain and melting snow.

Over the next couple of weeks we'll need to be on the lookout for possible flooding as the mercury rises and the snow melts.  The current snow cover on the ground has about one to three inches of water content in it.  This means if we were to melt that snow it would add up in some places to three inches of water!  Now, we're not going to completely melt that off within a weeks time, but with the potential for additional rainfall next week it may only increase the rate of melting and runoff.  Combine that with the fact that the ground is pretty frozen and the rivers have a fair amount of ice on them and this could be a recipe for flooding across parts of the Stateline.  We'll continue to monitor the situation going into next week, as you should too.  Again, if we get any rain with those warmer temperatures we may have a bit of a mess to deal with before the temperatures fall back below average the last week of February. 

Quick burst of snow for some this morning

The snow won't last long, but where it's coming down, it's coming down hard.  Visibility has been improving west of Rockford but the snow was quick to accumulate on roads with nearly an inch being reported out in Freeport.  In fact, there were reports of thundersnow in Madison around 9:30am!  The back edge of the heavier snow is now just west of I-39 and will continue to move east through Noon.  Snow covered roads will be slick into the early afternoon so be careful driving during the lunch hour.

Snow, some moderate at times, will continue to move east through Northern Illinois and Southern Wisconsin along a warm front.  Accumulations will remain minor, but the visibility could drop to less than a mile under some of the more moderate snow bands.  There could also be a few snow covered roads through this morning.  Once the front passes the snow will wind down later this afternoon.  Again, accumulations are expected to remain under an inch.

Bumps In The Road

We've been talking the last couple of days about a pattern change next week that would finally lead to a warm-up for the Stateline. But we've got a few weathermakers to get through before we can bask in the glory of above average temperatures.

Friday Night: The first "hazard" we have to deal with really isn't a big deal, but it's worth mentioning. Overnight lows on Friday will be right around 0°. If we do dip below zero, it would put us in 5th place for most days with below zero temps in Rockford for a single winter.

Saturday: Once again, not a major "hazard", but a few inches of snow will be possible for the start of the weekend. It shouldn't cause any major problems, but keep the shovel handy.

Monday: This is the day we're keeping an eye on. Monday's highs are expected to get into the mid and upper 30s. That would give us the chance for rain during the day before switching back to a wintry mix and snow for the evening and overnight. There is a chance we could also see some freezing rain and ice with this system, which would obviously cause some major headaches. Nothing is set in stone yet, but we'll update you as the models start to come together. -BA

Jet stream pattern change on the horizon

It's been a long time coming but there looks to be a break from the bitter cold we've felt now for the past month and a half.  The change will be coming in the jet stream pattern next week where winds will shift more from a north to south orientation like we've been in, to more of a west/southwest to east/northeast movement.  This will allow temperatures to modify actually above freezing and maybe even average beginning the middle of the next week!  The warm up will be nice but let's hope it doesn't get too warm, too fast.  With such a deep snow pack on the ground, warming too quickly could create flooding issues.

Here's a look at the current snow cover across the United States.  Even as winds begin to switch around to the southwest the air will be modified a bit by the snow extending all the way into Oklahoma and Kansas.  The expected temperature rise, at least this week, might not be that great but once the snow to the south is gone the warmer days will arrive.