Monday, December 5, 2016

Near Zero Wind Chills this Week

It's going to get cold and it will happen pretty quickly.  An incoming cold front mid-morning Tuesday will help get rid of the dense fog from Monday.  But don't be surprised if you wake up to dense fog Tuesday morning.

The front comes through mostly dry with Gulf moisture staying in southern Illinois and Indiana.  Low pressure associated with the cold front is currently producing snow over the High Plains and will bring blizzard conditions through Tuesday afternoon.  The heavy snow stays north with only a few flurries possible along the front for Northern Illinois and Southern Wisconsin.

Temperatures will slowly drop by Tuesday evening and really plummet following a strong cold front Wednesday.  A true Arctic air mass arrives Wednesday and Wednesday night - enhanced by moving over a freshly fallen snow pack.

Afternoon wind chills Wednesday could remain in the teens, but in the single digits Thursday and Friday.  Overnight wind chills will come close to zero degrees Thursday and Friday morning.

Slow Go on the Roads this Morning

Road crews did a great job clearing a lot of the snow that feel yesterday, but there is a different weather factor to contend with this morning. Thick fog has been developing in Iowa and has been continuing to thicken as our temperatures are falling. Clearing skies overnight allowed our temperatures to drop back into the low 30's. So not only do we have lowered visibility, but with temperatures hoovering in the low 30's, freezing fog is possible as well. This will be on the patchy side, especially on untreated roads. Make sure to take it slower on the roads, on sidewalks, and in parking lots.

We are drawing up moisture with southerly winds, along with added moisture from the recent snow pack is keeping the extra moisture around. A temperature inversion (temperatures rising with height) will trap moisture closer to the surface, it turn trapping the fog.

The fog will linger through the morning and into the afternoon. A dense fog advisory has been issued until 1:00pm.

We do expect visibility to slowly improve through this afternoon.

Not only does the fog present travel issues, but it will also keep temperatures much lower then where they could be. Highs had the potential to warm into the low 40's today, but the foggy conditions will keep temperatures colder today. This will also limit the melting of any snow, which will reinforce colder air for the end of the week.

Minimal Snow Chances this Week, But Winter Chill Arrvies. finally looks like winter across the Stateline, but this week it will really begin to feel like it. While some of the snow will melt today, the snowy ground will also help to reinforce the cold feel that will arrive later this week.

An incoming cold front that arrives Tuesday does bring a very small chance for flurries in the morning but its the cold that we will really notice. That front along with a strong low that will track across the Canadian border will help dislodge cold arctic air. Highs will only make it into the 20's beginning Wednesday, and will only make it into the low 20's Thursday, Friday, and Saturday. Not only that but wind chills will be in the teens and single digits through the end of the week. With snow on the ground, it reflects the sunlight and warmth, and so its harder to get temperatures to warm.

Some models indicate that relief from the cold arrives next week, but at this point its too far out to say.

The weather pattern this week will be slightly less active, with just minimal snow chances through the work week. A few flakes will fly, with a small chance for a light snow showers Wednesday night into early Thursday. However, it doesn't look to be a big impact to the area. Our next best chance for snow will be will an incoming system that we are watching on Saturday.

Sunday, December 4, 2016

Close to the Record

We came close to breaking the daily record for snowfall in Rockford.  Officially we recorded 5.3" at the Chicago Rockford International Airport.  This was just 0.4" shy of the daily snowfall record of 5.7" set back in 2010. 

Snowfall Totals

Here is a list of some of the snow totals we've received so far from the National Weather Service (thank you to everyone who has submitted snow totals, too!)

Please share your report with us:

First Snow of the Season Was a Big One

Mother Nature did not disappoint for the first snow of the season.  And it's not even 'officially' winter yet!  Snowfall totals from Southern Wisconsin and Northern Illinois ranged from 3" to 9".  Why such a big range?  A heavy snow band set up south of Rockford and was maximized on either side of I-88.  Most of the higher snow reports I've seen so far have been from Dixon, Amboy, Rochelle and DeKalb.  There, anywhere from 7" to 9" of snow fell. 

To understand why we received so much snowfall, we have to look at what was happening up in the atmosphere.  Early last week when the very first discussion of snow for the weekend was brought up, it was suggested that a very strong area of low pressure was going to develop as the northern and southern branches of the jet stream merged or 'phased' together.  As we got closer to the weekend it appeared that wasn't going to happen and the northern branch of the jet stream was going to become the more dominant branch locally - still pulling a strong low through.  When we look a looping water vapor image, the position of the trough ( or dip ) in the jet stream can tell us a lot.  The trough that moved through Sunday was negatively tilted.  Negatively tilted troughs tend to have more energy and instability associated with them.  And because of that a heavy band of snow occurred south of Highway 72 and really maximized on either side of I-88, producing the high snow totals.  Unfortunately these heavy snow bands are hard to forecast several days, and even sometimes hours, in advance.  And we don't know that they are going to happen until they're already underway.

Thankfully the snowfall has ended with only a few flurries east of Rockford.  Skies are beginning to clear west of the Mississippi River.  And with the recent snow and south winds, look for fog to develop and last through Monday morning.

Saturday, December 3, 2016

Seasons First Accumulating Snow Prompts Winter Weather Advisory

The Stateline's first snow arrives early Sunday, and prompts a Winter Weather Advisory for the entire area.

The snow will arrive before day break Sunday morning as it moves in from the west and spreads east. It will be a wet and slushy type snow, and will bring snow accumulations from 1-4" across the area. The higher totals rill range from eastern Iowa to western Winnebago county, with 2-4" more likely. While southeastern areas will most likely see 1-2" of the white stuff. As mentioned, it will be a heavy wet snow, and will fall at a moderate pace through the morning and afternoon hours. This could cause hazardous travel at times as it could drop visibility and cause slick roads that are snow or slush covered. It will also be hard to shovel, so take it slow and take breaks if you plan to shovel your driveway.

Use extra caution while driving, as we all remember our winter driving skills. Also, more accidents occur in light snow falls because we don't take them as seriously as high total events.

The snow could even mix with a bit of rain allowing for a light winter mix to drizzle as temperatures warm into the mid 30's by the late afternoon

. The snow will end around dinner time tomorrow, and we actually see sunshine arrive Monday with highs in the 40's!