Winter Weather for Monday: Everything You Need to Know

10:00pm Update: Expected wind gusts through Monday evening.  Highest wind speeds expected during the afternoon & early evening.

8:45pm Update: Growing a little more concerned with the potential for freezing rain to last longer in the afternoon. If that's does in fact happen, ice accumulations could had up to half an inch.  Combined with 45 mph wind gusts, big impacts likely Monday.

Second major winter event looks to be unfolding for Monday. Here is your Sunday evening forecast.  As I mention below, a change in a degree or two of temperature will have a major impact on precipitation type.  Definitely a difficult forecast!

Winter Storm Watch Now in Effect

 A Winter Storm Watch is in effect on Monday from 6:00AM until 6:00PM for Ogle, Lee, Boone, McHenry, and Winnebago Counties. For Carroll, Whiteside, Jo Daviess, and Stephenson Counties, the Watch goes until Tuesday morning at 6:00AM. For the counties in Southern Wisconsin, the watch is in effect until 9:00PM Monday evening. You can see that watch to the left. Every county shaded in blue is included in the watch.
The reasoning behind the issuance of the watch is a very large, strong and expansive storm system is getting its act together in Texas tonight. It will continue to strengthen as it begins to move quickly towards the northeast, which ultimately takes the low pressure center over Eastern Iowa and then Central Wisconsin. The system has already produced multiple tornadoes--some of which have been extremely strong, deadly and violent--reported this evening in Texas and Oklahoma. Some of those moved through the Dallas area, where several communities were flattened. On the other side of the state of Texas, there are Blizzard Warnings in effect for upwards of a foot or more of snow and winds gusting to 60mph.

With those two extremes, you can see how strong and potent this storm system is. The map to the left shows the current watches and warnings. Nearly every color on this map is a watch or warning associated with this storm system. There are Flood Warnings, Tornado Watches and Warnings, Blizzard Warnings, Winter Storm Watches and Warnings, Ice Storm Warnings, and more currently as a result of this major storm system.
Areas seeing the wintry side of this system will be seeing significant snowfall, freezing rain, sleet, or a mixture, in addition to very strong winds. Regions seeing the rain and thunderstorms with this system will see several inches of rainfall, the potential for flooding, and the potential for severe weather.

For the Stateline, the wintry side of the system will impact us for a long duration before slightly milder air works its way in and changes the wintry precipitation to plain rain where temperatures surpass the freezing mark Monday evening. The precipitation will begin as snow, sleet, freezing rain, or a mix Monday morning around sunrise and quickly overspread the region from south to north.

The precipitation will turn moderate to heavy during the morning into the afternoon hours. During this time frame, the majority of precipitation will be falling as freezing rain, which will allow a significant amount of ice to accumulate with such high rates of precipitation. Temperatures will slowly rise through the day into the lower 30's by afternoon. The exact location of the freezing line will be crucial in determining who sees what kind of precipitation, and, as a result, how much. Around 4-7PM, most locations, especially the southern and eastern counties, will be above freezing. That will alleviate some of the icing problems, and it will allow plain rain to fall.

Nonetheless, this event will be a significant winter storm. Locations south and east of Rockford will likely see 0.1-0.2" of ice. Winnebago County will see upwards of 0.25" of ice. Counties to the north and especially the west of Rockford will see 0.2-0.3"+ of ice. Sleet accumulations are possible as well for the entire region, but that is not expected to be significant. Snow accumulations are possible as well, especially towards the end of the system into Tuesday early morning. Most of the snow accumulation, if any, will be confined to areas from Rockford and points north and west. A few regions could see a half inch to a couple of inches of snow before the time the precipitation comes to an end.

The system will come to an end by 5-9AM on Tuesday morning, but troublesome travel is expected Monday into Tuesday morning for much of Northern Illinois and Southern Wisconsin. It is important to remember that this forecast could change quite a bit if the low pressure takes a track even slightly different than what is projected now. If the low moves further south, we will see more cold air, which means more snow and frozen precipitation. If the low edges north at all, we will see warmer air and more rainfall.

Wintry Weather Returns as Early as Sunday Night

The last week of December, and 2015, will not only be turning colder but also a little more active - with more wintry weather than rainy weather.

And it all starts this weekend.  Saturday morning clouds will continue to increase as temperatures gradually rise into the middle 30's.  This as moisture is pulled northward from the Gulf of Mexico.  If you're heading out Saturday morning, be prepared for fog and drizzle.  There could even be a few light rain showers. 

The rain will increase a little during Saturday afternoon, but it looks like the more steady rain will arrive Saturday evening into Saturday night.  Temperatures will be in the upper 30's, so it will be a chilly rain that falls. 

Some of those showers will last through early Sunday, with skies staying cloudy Sunday afternoon.  Strong high pressure will build across Minnesota and Wisconsin Sunday.  This will hold temperatures down in the middle 30's, but with a strong northeast wind through the day it will feel much more blustery.  The northeast wind will also cause a layer of drier air to move in over southern Wisconsin and northern Illinois.  This will be a key element in our precipitation that is expected to develop by Monday morning.

Low pressure will move in from the south, lifting north from Arkansas to Missouri Monday morning and into Wisconsin by Monday night.  With this type of winter storm track, it would favor more of a wintry mix for northern Illinois and southern Wisconsin.  Meaning a chance for sleet and freezing rain, with the possibility of minor ice accumulation for Monday morning.

The forecast, as of Friday night, would favor a snow/sleet mix closer to the Mississippi River with a sleet/rain/freezing rain mix over northern Illinois by Monday morning.  A very slow rise in temperatures above freezing (32 degrees) would change any frozen precipitation over to rain before switching back to a freezing rain/snow mixture by Monday night.  With this winter storm event still about 60 hours away, there is time for this track - and forecast - to change.  There has already been a slight shift of the low pressure system to the west which could mean a slight increase in surface temperatures over the area.  This would slowly eat away at our wintry mix potential leaving us with a higher chance for rain.

Either way, if you're returning back to work or have family heading home know that the weather will likely be a high impact for travelers.  Be sure to stay up-to-date with the weather this weekend!

Colder Weather For New Year's

We have been stuck in an above average pattern thus far this cold season. That has been a result of El Niño displacing the jet stream to our north. That pattern results in milder temperatures for the Upper Midwest, Great Lakes, and Northern Plains. However, forecast models are picking up on a pattern change as we head towards New Year's and ring in 2016.
That pattern change is in the form of much colder air. A breakdown in the ridge that has dominated in the eastern half of the country will occur the week of New Year's, which will allow colder air to move in from Canada. That is evident on the map above that shows the geopotential heights. That is a meteorological term that could be discussed for months. What you need to know is that areas of blue and green represent lower heights, or colder temperatures. On the other hand, the areas of orange and red--what we have been seeing this winter--are large heights, or warmer than average temperatures.

This pattern has been showing up on forecast models for quite some time, so there is consistency among the models, which is reassuring. We will get colder? Yes. How cold? It is difficult to answer that with high confidence as of right now. However, one forecast model is showing temperatures during the nighttime around New Year's Day in the teens and potentially single digits.

In fact, here are the projected temperatures on the morning of January 1st. Note the influx of much colder air from Canada resulting in much of the country seeing sub-freezing temperatures. Teens are showing up over Northern Illinois and Southern Wisconsin, which would be some of the coldest air we've seen this year. Is this going to happen? Not exactly. This is simply a model's thoughts on what the morning low temperatures will be on January 1st. What is important is that it shows the colder air like the long-range model above shows, and it shows how cold we could get.

Does the cold mean we will also see more wintry weather like snow? Not necessarily. It increases our chances of seeing snow simply because the colder air will allow more frozen precipitation to fall instead of plain rain. You still need a storm system and/or low pressure to develop and bring precipitation with them. Just having cold air in place is not enough. The good news for any snow lovers out there is the models have been very consistently showing a low pressure system developing in Texas on Sunday and strengthening as it moves northeastward towards the Stateline.

That low's exact track will dictate whether we see snow or rain or a mix. If enough cold air can hold its place over the region, then we could see much more snow. If the low tracks closer to Rockford, it will pull warmer air with it, which would hinder our chances of seeing snow. Currently, the models track the low over Champaign, if averaged together. That would allow enough cold air to be in place to support some snow. How much? That is impossible to say with high levels of accuracy as of now, but one model is showing several inches. Here it is:

Christmas Planner

After a couple rounds of rain and strong winds yesterday, the weather turns  peaceful in the Stateline for Christmas Eve and Christmas day.

Temperatures today will climb to about 40° under mostly cloudy skies with winds from the SW at 5-15 mph. There is a small chance for light snow showers as we head through the mid-afternoon and early evening. A strong wave of energy is currently bringing snow into western Iowa and will track into the Stateline. Little accumulations are expected, but this could cause some slickness on the roads, so use a little caution as you head home from work.

As Santa drops off his presents in the Stateline tonight temperatures will be fall into the upper 20's under mostly cloudy skies. Evening flurries are possible early in the evening before drying out overnight.

Christmas day will be a beautiful afternoon with temperatures in the low 40's and a lot of sunshine.

Much Colder Air Moving In; Snow Next Week?

After a cold front moved through this evening, temperatures have begun to fall as colder air is ushered in from the north and west. That means it's time to say "goodbye" to the mild 50's we saw on Wednesday. By the time we wake up on Christmas Eve morning, temperatures will be roughly 25° cooler than what we saw Wednesday afternoon. However, it will still be an above average day in terms of low and high temperatures on Christmas Eve despite it being significantly cooler.


The cooler air will remain in place for Christmas Day with temperatures only expected around 41°. But, that is still above average in terms of temperatures. Rain moves in on Saturday with slightly milder air arriving, followed by a few flakes possible on Sunday.

Then, our eyes turn to Monday and Monday night, which is when another stronger storm system is expected to move into the Stateline from Texas. The low pressure associated with that system is expected to be rather strong as it moves northeastward towards the region. Therefore, plenty of moisture will likely be available. Here is the most likely scenario according to the forecast models as of tonight:

With a track like this, the low will be close enough to the region to draw in enough warm air to give the Stateline a mainly rain event. And that is typically the case with these winter season storm systems. The stronger they get, the more warm air they draw in. And the closer they are to the Stateline, the warmer we are. Therefore, with these winter season storms, we look for the lows to move across Southern Illinois into Central Indiana if we want sufficient cold air to support snowfall. With Monday's storm system, it looks like it will move slightly too far north to allow an accumulating snow to occur for much of the Northern Illinois and Southern Wisconsin region.

Now, there is a possibility that the models are overdoing the strength of the low, and therefore taking it too far north. This is the other potential track the low could take--and this track has been suggested by the models as well:

With a track more similar to this, there is a higher probability of seeing snowfall, which could accumulate. So it is a storm system that bears watching, especially because we have not seen much winter-like weather in December.

Wednesday Afternoon Storm Update

 5:32pm Update: A line of showers and thunderstorms is approaching the region from the southwest now. It has entered Jo Daviess, Carroll, and Whiteside Counties. So far, nothing severe for the Stateline, but moderate to heavy rain and lightning have been reported. The severe threat does not look as concerning as it awhile ago, but there is still a threat for some severe weather as this moves through this evening.


5:10pm Update: Thunderstorms continue to arc northeast through the Quad Cities, with a tornado warning earlier for the Quad Cities.  As low pressure moves through northeast Iowa, the amount of spin in the atmosphere will help sustain these thunderstorms.  

4:41PM UPDATE:
Here is the current radar as of 4:41PM this afternoon. Scattered showers and storms off to the southwest will continue moving quickly towards the region. Some of them have been strong to severe at times. Also on the radar is a rough estimate of when the line will affect portions of the Stateline this evening.

3:20PM UPDATE:
The Tornado Watch out until 8PM includes only Whiteside County at this time. This watch could be expanded to include more counties across the viewing area this afternoon.

3:00PM UPDATE:
As the newest model data come in, the time period with the highest probability of thunderstorms, including severe weather is from roughly 4:30pm until 8pm as storms that are currently developing in Northeast Missouri strengthen and rapidly move towards the Stateline from the southwest. Below is the current radar and the timeline for the rain and storms.

1:00PM Quick afternoon update: A severe watch is possible just south of the Stateline area. After rain and storms from earlier this morning, there is some clearing taking place across portions of Missouri as dry air wraps in around the low. Along with this a strong shortwave tough, or band of energy and upward motion, is being noted ahead of a cold front. With this there is plenty of atmospheric shear or winds changing direction with height in the lower levels of the atmosphere. We will watch for individual storm cell development to the southwest this afternoon, because those types of storms have a better ability to rotate. In this area heavy rain, damaging winds, hail, and an isolated tornado is possible.

With today being one of the busiest travel days of the year, you'll want to stay 'weather aware' today, as there is a threat for strong to severe storms for the Stateline this afternoon.

The rain that moved in this morning is beginning to lessen a bit as dry air filters in. Currently watching to the south west in Missouri where dry air is wrapping in around the low pressure. As the dry air moves it, it erodes the cloud cover in place. If the cloud cover is gone, the sun is able to heat the ground and the instability grows. Instability is a key ingredient for storm develop, and plays into our severe weather threat for the afternoon. We didn't see much instability earlier and thats why the rain and storms stayed below severe limits.

So getting into the forecast for tonight and our risk for severe weather. All of northern Illinois and southern Wisconsin is under a slight risk for severe storms (yellow shading). This means that isolated severe storms are possible as we head into the late afternoon. A bigger threat for severe weather is towards the southern tip of the state, southern Indiana and Ohio, as well as into portions of Tennessee and Kentucky with an Enhanced (orange) and Moderate (pink) risk in place. Their hazards include all severe possibilities, heavy rain, strong damaging winds, hail, and even tornadoes. So if you are doing any traveling today make sure you have a way to receive watches and warnings if any are issued.

For the Stateline area, our bigger concerns will be heavy rain, fast moving storms, strong damaging winds. There is a smaller risk for a tornado, it is not a zero threat we can't rule one out, but it isn't a large threat. The higher probability area to possibility see a tornado would be near the Mississippi River in northwestern Illinois, because this is where the low looks to track. Near the low pressure, winds will be turning with height, giving a bit of wind shear, which is also needed for strong storms.


The timing of these storms looks to be between 4pm and 8pm tonight. This comes as we get the low pressure to track northward into Missouri and Iowa today, and a warm front also lifts northward. We also combine this with a very warm and moist air mass. Temperatures today will break the old record high for today (which is 57° set in 1941) as our temperature already sits at 58°. Our dew points are also very high for this time of year, as they are climbing into the 50's as well. This is increasing the instability which is needed for storms.

These storms will be fast movers as well, as they get a lot of help from strong winds in the upper levels of the atmosphere, so you won't have much time to react as the move.

Make sure to keep checking back as we will continue to update the blog, facebook, and twitter!