Less is more, right?

Radar returns look a lot more impressive than what is actually occurring at the surface.  We did have some light snow across parts of the region earlier this morning with higher totals reported in our far west/southwest counties.  Dry air stuck around a little longer than expected which caused a lot of the snow to evaporate before reaching the ground.

The trough of low pressure that extends northwest from the low that is moving into the Mid-Atlantic will continue to move east through this afternoon.  An upper level disturbance currently moving through Iowa will continue to push dry air into the mid-levels of the atmosphere.  Any snowfall that is left over as this low moves through may see a brief period of light freezing drizzle mixed in.  This will more than likely occur across the far western part of the WTVO forecast area.  Otherwise look for minor accumulations through the remainder of the afternoon.

Thursday Morning Weather Update

The Winter Weather Advisory has been cancelled for all Northern Illinois counties except Jo Daviess, Carroll, Whiteside and Lee.  We're also trimming back on snowfall totals this morning with only about an inch or so expected across North-Central Illinois.  A little more accumulation can be expected where the advisory remains.

(8:32:16 AM) nwsbot: DVN: 1 Wnw Morrison [Whiteside Co, IL] trained spotter reports SNOW of M2.0 INCH at 08:31 AM CST --

(8:23:13 AM) nwsbot: LOT cancels Winter Weather Advisory for Ford, Grundy, Iroquois, La Salle, Lee, Livingston [IL]


(7:24:19 AM) nwsbot: DVN: Erie [Whiteside Co, IL] trained spotter reports SNOW of M3.0 INCH at 07:23 AM CST --

(12/16/2010 6:49:11 AM) nwsbot: DVN: Elizabeth [Jo Daviess Co, IL] co-op observer reports SNOW of M1.7 INCH at 06:48 AM CST --

(12/16/2010 6:44:08 AM) nwsbot: DVN: Galena [Jo Daviess Co, IL] co-op observer reports SNOW of M1.5 INCH at 06:43 AM CST --

Winter Weather Advisory

11:45pm Update: Things aren't always as they seem! Although the current radar image suggests that the leading edge of the snow is now into the Rockford area, snow has yet to be reported on the ground. Even a bit further west in Freeport, only cloudy skies were reported at the last observation. Both Savannah and Moline, however, are reporting light snow.

The snow has been struggling to move into the area with the cold, dry air that we have in place. It's also moving further away from the area of low pressure in the southern plains that's creating the instability for this shield of precipitation over the Midwest. Although we're still under a winter weather advisory until noon tomorrow, we'll probably be on the lower end of the 2-4" of precipitation that we've been predicting. 

1:00pm Update: The snow that has been falling in Iowa has been slow to make it's way east so far this morning.  Because of this, I am going to push back the starting time of the snow.  Looks like it will now begin more towards late evening and overspread the Stateline overnight.  Still going to go with roughly around 3" to 4" across Northern Illinois with less amounts east and higher amounts to the west.  We'll continue to monitor the weather this afternoon and let you know if we see any changes. 

9:00am Update: Light snow is now beginning to fall across parts of northern Iowa this morning.  Dew points are still fairly dry across much of the Stateline and even into eastern Iowa.  Area of low pressure is now beginning to move into western Oklahoma and will continue to move east across Missouri and southern Illinois by this evening.  As it does warmer air along with a little more moisture will begin to move northward along a trough that will extend from the low into the northern Great Lakes.  Look for light snow to begin later this afternoon west of Rockford and then spread eastward through the evening, possibly impacting the evening commute.  Snow will continue through the overnight and could be moderate at times.  As of right now we're looking at anywhere between 3"- 6" of accumulation by Thursday afternoon.  Snow to water ratios will be high enough to allow some of the snow to fluff up closer to the 6" mark, especially across parts of western and northwest Illinois.  Accumulations are expected to be less across southern/southeastern Wisconsin - ranging anywhere between 1"- 3".


A Winter Weather Advisory is in effect for Jo Daviess, Stephenson, Carroll, Whiteside, Winnebago, Boone, Ogle, Lee and DeKalb Counties beginning this afternoon and lasting through Thursday morning.

Snow Accompanying Warm-Ups

The 9pm central time observations tonight (12/14/10) show 3 degrees with partly cloudy skies in Rockford, IL. In the mean-time, it's 24 degrees in Munising, MI... Some 300 miles to our north. The main reason it's warmer up there? It's snowing! Yes, in situations where an arctic airmass is sitting over the Midwest, clouds and snow can save your temperature from "falling through the floor!"

Of course, clouds act like a blanket at night, and inhibit radiational cooling. But if snow is falling at a given location, it can be warmer still because snow formation is an exothermic process. This means the creation of snow releases heat into the surrounding atmosphere. Here's a brief explanation why:

Snow forms when droplets of water vapor (in gaseous form, of course) condense onto a dust particle or some other microscopic material in the air. The water quickly goes from liquid to solid phase in temperatures below freezing. This phase change from liquid to solid actually releases a small amount of heat into the atmosphere.

Light snow is forecast to move into the Stateline Wednesday night and Thursday morning. Along with the snow, our high temperatures will warm into the low to mid-20s, and our lows will moderate into the teens on Wednesday night. This is still below average, but better than the teens for highs and sub-zero lows we've seen over the last 36 hours!

Midweek Snow

Looks like the active, chilly weather pattern will continue at least for the next week or so.  An area of low pressure will move south of the Stateline Wednesday night with accumulating snow likely by Thursday afternoon.  Because there is a chance for an extended period of light snow, accumulations in some spots could fluff up to 3" or more.

Geminid Meteor Shower

The Geminid Meteor Shower peaks overnight tonight between about 12am and 6am. If you're a night owl or an early riser, you should have a good opportunity to see the geminids right overhead since clear skies are expected over the Stateline tonight, and there's no moon to interfere with viewing. The geminid shower is composed of debris from the extinct asteroid 3200 Phaethon and has increased in intensity since it was first observed in 1862. Even though tonight is the peak of this shower, you can still observe it in the night sky through December 18th. --TS

Wind Chill Advisory

While the Wind Chill Advisory for the Stateline has been allowed to expire, the cold will continue through the afternoon.  Wind chills will remain below zero for the better part of the afternoon. 


10:00am Update: Wind Chill Advisory has been allowed to expire for Stephenson, Jo Daviess, Carroll and Whiteside Counties.  Although it will remain very cold today, increasing temperatures and diminshing winds will allow for wind chills to slightly improve.  Please continue to take the necessary precautions to keep yourself warm today if headed outdoors. 

A Wind Chill Advisory is in effect for southern Wisconsin and northern Illinois through Monday morning.  Temperatures this morning have fallen into the single digits but wind chill values have fallen to as cold as -25° in some locations.  A gusty northwest wind will remain with us through the better part of the day keeping wind chill readings below zero.  Actual highs will have a hard time making it into the lower teens despite the sunshine expected this afternoon.