Heavy rain Wednesday evening switches over to snow overnight

 

Another round of heavy rain is beginning to move into northern Illinois and is expected to continue over the next few hours. Flooding will not be a concern as rainfall totals near one inch during that time, but ponding water on the roads is likely to occur. This could create, along with the heavy rainfall, difficult driving conditions Wednesday evening. Temperatures will be in the 40s during that time, but colder air wrapping in around the low will turn the rain into snow.

This transition appears to take place after 9pm/10pm and continue into the predawn hours of Thursday. Winter weather headlines have been issued just north of the immediate region, nothing locally yet. The transition over to snow may be quick, with heavier bursts of snow occurring during that time.

The heavy, wet snow will continue through the night and may be heavy enough to overcome some of the warmer surface temperatures. If so, slushy accumulations are possible on the roads in northern Illinois. Accumulating snow is likely in southern and central Wisconsin where several inches of snow could fall. Closer to the Stateline snow totals could reach an inch, or a little over, by Thursday morning, lesser amounts to the south.

The precipitation will be done Thursday morning

but there could be some impacts on the roads with any slushy snow that may have accumulated. Winds will turn back around to the southwest for Thursday afternoon with temperatures only reaching the mid 30s. Scattered snow showers are likely to occur during the afternoon, picking up a little more in coverage Thursday night. Another 1-2 inches will be possible between any snow showers that fall between Thursday afternoon and Saturday.  

More Rain On the Way, Arctic Air Arrives this Weekend

More Rain to Come:

A large and powerful storm system over the central U.S brought a chilly rain, mixed snow showers, and a strong wind to the area overnight. Rainfall totals as of 6AM show that most of the region was able to pick up a good .25" to .75 of rain. 

With more rain in the works for our Wednesday, it'll be important to once again have the rain gear with you before you leave the driveway.  

Cloud cover will dominate our skies from start to finish, with occasional on and off showers passing through from time to time. As a secondary storm system nears the region, the radar will begin to fill back in as we head into tonight. 

In addition to the rain that fell last night, most will have the opportunity to pick up an additional .5" to 1.0". Once the midnight hour approaches, the activity will undergo a downward trend in intensity. Compared to today's forecast, Thursday will be a lot less hectic. However, there will still be enough moisture swinging around the low to support the potential of a few flurries and light snow showers.

Arctic Cold Filters In:

During the Thursday-Friday time frame, our storm system is going to undergo a process in which it will transfer it's energy to a new low that will form off the Carolina coast. It's during this time in which the focus will shift from the wintry precipitation to the Arctic cold in which the old low helps filter into the lower 48. High temperatures will drop from the upper 40s today to barely making it out of the 20s come Friday afternoon.

Along with the incoming cold, Friday also features the potential for a few snow showers. The coldest air arrives over the weekend, dropping highs into the upper 20s both Saturday and Sunday. 

Along with the colder days comes colder night as lows will be landing in the mid to upper teens. How long is this Arctic air going to stay? Well, long-range outlooks showcase this upcoming cold sticking around into the days before Christmas. All we need now is for mother nature to cooperate by sending us a storm system or two that will at least leave an 1" of snow on the ground by the time we're waking up on Christmas morning. Fingers crossed.

Rain Moves in Late, Turning Very Cold By the Weekend

Turning Active:

Yesterday marked the 8th straight day in which the Stateline sat under a mostly cloudy to overcast sky. Unfortunately, our  pattern only gets more active from here, meaning there won't be much room for sunshine in the forecast moving forward. On the flip side, this morning will mirror the weather conditions felt to kick off the day yesterday, with a lot of clouds and temperatures in the 30s. Despite the dry start to our Tuesday, I would still take an umbrella with you as we can expect rain chances to increase as the day carries on. 

Rain Timing:

Forecast models bring the first opportunity for rain towards the late afternoon hours, with it becoming more widespread during the evening. Once the wet weather commences, we can expect several hours of moderate to heavy rainfall rates to follow. 

As we mentioned previously, severe weather will not be a concern with this activity. However, a few rumbles of thunder cannot be ruled out. Now, along with the heavy downpours does come a rather gusty wind out of the east-southeast. With winds ramping up roughly 5000 ft above the surface, wind gusts at ground level will likely land in the 30-40 mph range overnight. So before this mess moves in, I would take the time to secure any Christmas decorations or loose objects in your yard.

Late Week Cold:

It's not until we hit the early stages of Wednesday morning that we begin to see the widespread rain break apart, leaving us with scattered showers for the remainder of the day. 

Again, having the umbrella will be a necessity. From start to finish, I do think most will have the potential to pick up 1"-1.5". Wednesday night is when the focus switches from the rain to the bitterly cold as the same system will help filter our next round of Arctic air. Highs Thursday afternoon are set to only peak in the upper 30s, with low 30s on tap for Friday. With Arctic air continuing to filter in aloft, highs both Saturday and Sunday will be severely limited to the upper 20s, with overnight lows in the teens. 

Long Range Outlook:

Looking ahead to the days leading up to the Christmas holiday, there are strong signals of well-below average temperatures spilling spilling across much of the lower 48. The highest probability, residing over the northern Plains, the Great Lakes, and even into the deep south states. 

So it's safe to say, winter will be in full force from this weekend into next week. Now, we just need a storm system to come in late in the week next week to give us a good chance at seeing a white Christmas. But as of this morning, it's still way to far in advanced to set anything into stone. Only time will tell folks.

Cloudy Monday, Rain Holds Off Until Tuesday Evening

Cloudy Month So Far:

For the most part, high temperatures in Rockford have landed above-average since the beginning of December. However, things over in the cloud cover department have gotten quite boring during this stretch. I say that because 8 of December's 11 days have come in with an average cloud cover value of 80% or higher, which does include the last 3 days. Unfortunately, that trend unfortunately is set to carry on into the new work week as our weather pattern remains relatively active moving forward. 

Clouds Don't Budge:

If there was any chance for us to see a few peeks of sunshine, it would be late in the day. Otherwise, we can expect skies to remain filled with clouds from start to finish. Like Saturday and Sunday, highs for most will peak in the upper 30s, with a spot or two briefly touching the 40-degree mark. Low-level moisture in our atmosphere will keep skies mostly cloudy overnight into Tuesday morning, with temperatures falling into the low 30s. 

Next Storm System:

Clouds remain in place Tuesday as our next potent system takes shape over the midsection of the United States. Like the last dynamic late-fall storm system to pass on through the Midwest, this will be a rain-maker for the most part. 

However, accumulating snow  will be likely on the northern side of the deepening low, with the high potential for significant severe weather residing across the deep south. As of this morning, the Storm Prediction Center placed a good chunk of northern Louisiana under an enhanced risk (level 3 of 5) for severe weather. In the warm sector of this powerful storm system, damaging winds and tornadoes (some strong) will be the biggest concerns, followed by large hail and heavy rainfall.

Back home, rain aims to develop late Tuesday afternoon into Tuesday evening, becoming a bit more widespread into Tuesday night. It's also during this time in which the pressure at the surface will tighten up, allowing this activity to become wind-driven. 

As previously mentioned, the focus for severe weather will be well to the south. However, a few rumbles of thunder from time to time is not out of the question. When it comes to temperatures, highs will peak in the low 40s Tuesday, with a slow rise in temperatures expected into Wednesday. That will place us close to the 50-degree mark by Wednesday afternoon. Unfortunately, we won't be able to enjoy the warmth as rain will be likely for much of the day. From there, temperatures will drop, becoming cold enough for a light wintry mix Wednesday night into Thursday.

Winter Weather Advisory Issued, Slushy Morning Commute Ahead

Winter Weather Advisory:

Earlier this morning, a winter weather advisory went into effect for our counties hugging the Illinois-Wisconsin border. For those north of the border, that will be in place until 6PM. 

For our northern Illinois counties, we can expect this advisory to expire around 1PM. As we've been hinting at the past few days, the main concern with this storm system will be the impacts it brings for those traveling during the morning commute.

Timing of Impacts: 

If you plan to travel, it'll be important to implement extra travel time into your morning routine. Then once you're on the roadways, remain focused and travel at a slower speed. Forecast models do place the rain/snow mix line right near the Illinois-Wisconsin border early on, before shifting it back south shortly after sunrise. 

This will result in a changeover to wet snow for those who live along and north of U.S 20. Whereas those who live south of U.S 20 will still be experiencing the wintry mix portion of the system. Further south near Interstate 88, precipitation remains as all rain. Once that changeover occurs, we'll have a 2-3 hour window for slushy accumulations before conditions begins to wind down. 

Overall, I do think those in extreme northern Illinois will be able to pick up 1"-3" of slushy snow, with the potential for 4" totals up in southern and southeastern Wisconsin. Even after the storm departs, the low potential for patchy drizzle lingers into the first half of the night. 

Otherwise, expect a mostly cloudy sky with temperatures falling back into the lower 30s prior to sunrise. As for the weekend, most of it will be dry but mostly cloudy. The only precipitation chance we have comes in the form of a light wintry mix Saturday evening/Saturday night. Temperatures for both days aim to peak on either side of the 40-degree mark.

Foggy Morning Commute, Rain/Snow Mix Moves in Overnight

Foggy Once Again:

With our temperature and dew point values relatively close to one another, our day is starting off once again with a little bit of fog. While it may not be as thick as the fog we had Wednesday morning, the potential for dense fog is still not out of the question. Freezing fog will also be a possibility considering that we have  sub-freezing temperatures in place. All in all, allow for extra travel time this morning.

Next Storm System:

Earlier this morning, the National Weather Service placed areas stretching from the Nebraska Panhandle to S. Wisconsin under a WINTER WEATHER ADVISORY. Nothing for our neck of the woods at the moment as most of our Thursday believe it or not will feature mainly dry conditions. With that being said, an isolated shower or two cannot be ruled out during the afternoon as we wait for the main round of precipitation to arrive.

Timing It Out:

Precipitation chances ramp up during the mid to late evening hours, likely starting out as a mix of rain and snow. Much of the night in fact features a chance for mixed precipitation. However, there will be periods in which we will see the precipitation primarily falling as a chilly rain. 

Temperatures for most will remain above the 32° mark into Friday morning. But colder air wrapping in around the low could result in a switchover to a wet snow for those who live along and north of highway 20. Minor accumulations will be possible but will likely stick to grassy and elevated surfaces. In southern Wisconsin an inch or two could fall, with lesser amounts to the south. Although we're not expecting much, it will still be important to implement extra time in your morning routine for travel. 

Things look to rap up early Friday afternoon, with skies remaining mostly cloudy for the remainder of the day. Temperatures on Friday will warm to right around 40 degrees. There is another chance for some rain and snow Saturday afternoon and evening with drier skies for Sunday.

Foggy skies again Wednesday night; Rain moves in Thursday

 

Skies were mostly cloudy for much of Wednesday afternoon, but we did manage to squeeze out a little sunshine late in the day. The clearing, however, has allowed some fog to develop and continue across northern Illinois and southern Wisconsin. While it may not be as thick as it was Tuesday night/Wednesday morning, reduced visibility can be expected through the morning Thursday. Temperatures will fall back below freezing and this could mean freezing fog may occur again.

High pressure will turn winds to the east Thursday giving us a little dry air throughout the first half of the day. As low pressure moves in from the south Thursday evening, rain showers are expected to expand north across Illinois, reaching northern Illinois during the late afternoon and evening. The leading edge of the precipitation may mix with some light snow near the state line Thursday evening and overnight.

Temperatures for most will remain above freezing, but colder air wrapping in around the low Friday morning could cause a switchover to wet snow for some across southern Wisconsin and far northern Illinois. The best places for some snow during that time look be along and north of Highway 72 and 20. South of that corridor it'll remain mostly rain. Minor accumulations are possible but will likely remain on grassy and elevated surfaces. In southern Wisconsin an inch or two could fall, with lesser amounts to the south.

So far locally there are no winter headlines, but a Winter Weather Advisory does exist for areas across the Plains and Midwest. By Friday afternoon skies will begin to dry out with cloud cover lasting through the evening. Temperatures on Friday will warm to right around 40 degrees. There is another chance for some rain and snow Saturday afternoon and evening with drier skies for Sunday. Highs through the weekend will warm into the low 40s.