Windy Friday ahead of evening scattered showers

 Rockford "split the gap" between two areas of accumulating snow from last night into early this morning. DeKalb saw 2.5" of snow, while Rockford only got a trace! That snow kept temperatures around 10-20° lower than surrounding areas this afternoon, especially along the Northern swath from Iowa into Wisconsin!

Overnight, our temperature will dip back into the upper 20s but will hold steady after midnight amid a strengthening Southerly wind. This wind could gust upwards of 35-40 mph around midday tomorrow before winds ease up a bit into the late afternoon. Temperatures will reach into the mid-50s as a result of the warmer air transported our way by the wind.

That wind will lead into our next weather system arriving later that evening. Many will remain dry through 5/6PM, but scattered rain showers will spread across the area after 6PM. A few of these showers may have heavier rates of rain within them, but thunderstorms are not a concern at this time.

Scattered showers could continue through 12/1AM. As colder air filters in from the Northwest, we could see a brief flip over to mixed precipitation or snow showers after midnight. Any snow we do see will not last very long and any accumulations would be very limited.

That will set up a cooler Saturday with highs only reaching back into the mid-40s despite a partly cloudy sky. Sunday morning will bring widespread rain showers that will gradually diminish in coverage toward the evening. High temperatures Sunday will at least briefly touch the low 50s but overnight will see temperatures drop into the upper 20s again.

Turning chilly for the first day of spring

Go figure. In classic Midwest fashion, northern Illinois saw a round of showers and strong storms on the final day of winter. But for the first day of spring which is today, we're talking slippery travel, snow chances, and chilly temperatures. 

The last of the snow showers is pushing through and should be out before sunrise. Just keep in mind that there may be slick spots during the morning commute as leftover moisture may freeze. 

The only counties that remain under a WINTER WEATHER ADVISORY is DeKalb and Lee Counties. That expires at 7AM. 

The National Weather Service has been cancelling out the WIND ADVISORY, though Ogle, DeKalb, Boone, Winnebago, McHenry Counties in northern Illinois as well as Green, Rock, and Walworth Counties in southern Wisconsin remain under said advisory until 7AM this morning.

Winds could still pack a punch early in the day, gusting up to 30 mph. It's by the afternoon we see a decrease in both winds and cloud cover, leaving afternoon highs hovering around the 40-degree mark. With today's wind being out of the northwest, expect wind chills to be suck in the low 30s. 

High pressure then settles in overnight, keeping conditions quiet and seasonable into Friday, with temperatures falling the upper 20s. 

This break from the strong winds doesn't last very long as winds ramp up on the backside of said high pressure by Friday afternoon. On the flip side, these winds will be oriented out of the southwest, allowing afternoon highs to peak in the mid 50s. 

Why we had dirty rain Wednesday

 

If you stepped outside either during the morning or afternoon Wednesday, you may have noticed your car was a little dirtier than what it was before - even after the rain came through. We received many comments and pictures from viewers of their cars wondering where all the dirt and mud came from.

To answer this question, we have to look west and southwest - well west and southwest. A strong trough of low pressure in the jet stream (a dip in the jet stream) developed out west late Tuesday night. Fast moving jet stream winds at the base of the trough, nearly 115 mph, created strong winds near the surface. Those strong surface winds were able to pick up a lot of the dirt across parts of Texas, lofting it into the air several thousand feet above. The dust and dirt then became suspended within the jet stream winds, traveling through Arkansas, Missouri, and Illinois Wednesday morning before moving east late in the afternoon. The dust was so thick it caused significant issues with visibility at times over parts of Arkansas and Missouri.

Parts of Oklahoma and Texas, as well as New Mexico and Arizonia, have been experiencing very dry conditions. The storm system late Friday caused fires to rapidly spread in Oklahoma as major dust storms occurred. A lot of what we experienced Wednesday was left over from what had occurred over the Southern Plains and Southwest from late last week and the weekend.

Once in the air and clouds the dust and dirt particles act as 'collection points' (known as condensation nuclei) for water droplets to form on, helping to create rain drops. As the rain drops fall from the clouds the dust particles travel with it. When the rain hits the surface, we are left with the visible dust and dirt on things like cars, sidewalks, and the grass. This is why your car looked dirty, or why the ground in some locations had more of a tan look to it.

Wind whipped snow showers possible into Thursday morning

 After the line of non-severe thunderstorms Wednesday evening, we will see a bit of a lull for a few hours before precipitation rolls back in. Colder air filtering in from the Northwest will flip rain over to a heavy and wet snow late this evening.

Snow showers could last into the early hours of Thursday morning, peaking in coverage and intensity near and shortly after midnight. We could see some heavier bands of snow, significantly limiting visibility as that snow comes down. Snow showers will spread out of the Stateline toward sunrise Thursday morning. Snowfall may accumulate mainly on grassy and elevated surfaces, up to 1-2" could be possible. Similar to Sunday's snow, impacts to roadways will remain limited, unless we see multiple intense bands of snow.

These snow showers will be paired with a stout wind from the North then Northwest. Winds could gust upwards of 35-45 mph at times starting late Wednesday evening and lasting into Thursday morning.

A wind advisory will go into effect this evening for the entire Stateline for that potential of 45 mph gusts. Winds will begin to ease a bit into Thursday afternoon with a bit more sunshine returning for the second half of the day. Temperatures will only rebound to around 40°.

Wednesday late afternoon weather update

 6:30pm Update: The severe threat has pretty much ended for the region Wednesday evening as the strongest storms have now moved into Indiana. There are some showers and isolated storms near Peoria that have formed just north of the surface low, but over the last 30 minutes they have weakened quite a bit.

We will see some showers fill back in from the southwest between 7pm and 8pm before a transition over to snow occurs from west to east.

Scattered showers and thunderstorms continue to move across northern Illinois, now entering into southern Wisconsin late this afternoon. While there were a couple isolated severe thunderstorms with what came through this morning, the severe threat for the afternoon has remained further south in central Illinois.

The warm front that brought our temperatures into the 60s Tuesday drifted south overnight, settling near I-80 throughout most of Wednesday afternoon. This resulted in a much more stable environment across northern Illinois. It also caused our temperatures to remain in the 30s and 40s, quite a bit colder than the original forecast. South of the warm front, however, temperatures warmed into the 60s and 70s. And this is where most of the active weather has been where there are current severe thunderstorm and tornado warnings.

The biggest threats with any storms locally will be hail. There have been quite a few reports of pea sized hail with the storms as they've moved through. The leading edge of the storms are now stretching from Rockford down through southern DeKalb County. This line will pass through the region by 6pm-7pm.

Severe storms possible Wednesday afternoon, strong winds and snow to follow

For the 2nd time in a week, a potent area of low pressure is scheduled to sweep across the central U.S, bringing with it a variety of impacts. Locally, severe weather, strong winds, and accumulating snow is all on the table over the next 24 hours. 

Let's begin with the severe potential. In their latest round of severe outlooks, the Storm Prediction Center pushed the Level 2, Slight Risk further north to now include Rockford, Belvidere, and Freeport. This puts S. Wisconsin under a Level 1, Marginal Risk. Further to our south (I-80 south), areas have been placed under a level 3, Enhanced Risk.

  

Ahead of the main surface low, a round of showers and storms will pass through during the mid to late morning hours. This will be scattered and elevated in nature, only posing a risk for small hail. A period of mixed sunshine is likely to follow during the early to mid-afternoon hours, which will allow the atmosphere to destabilize or re-energize.

 

The one thing we will have to watch is the position of the low and associated warm front. Forecast models place the warm front just south of highway 20 and south of the front is where the best ingredients will reside for strong to severe storms. 

North of the front, not so much as winds will be cooler out of the northeast. Storms that do manage to form this afternoon and evening will pose a risk for damaging winds and a few tornadoes.

Again, make sure to have multiple ways to receive watches and warnings this afternoon. Once the low is located to our east, cooler northerly winds on the backside of it will help transition rain to wet snow overnight into Thursday. Be on the lookout for slippery spots tomorrow morning. Any chance for snow should come to an end before midday, leaving us to dry out Thursday afternoon. Temperatures will be much cooler, landing in the low 40s.

As previously discussed, strong winds will be once again a headline locally, especially overnight tonight into Thursday morning. Peak winds could be as high as 45 MPH. For that, the National Weather Service has placed the entire area under a WIND ADVISORY. For Winnebago, Boone, Ogle, Lee, DeKalb, and McHenry Counties, this will run from 10PM Wednesday to 7AM Thursday. For Carroll, Whiteside, Jo-Daviess, and Stephenson Counties, this will run from 7PM Wednesday to 7AM Thursday.
 

Severe storms Wednesday afternoon followed by snow showers Wednesday night

 Cloud cover was a little more abundant Tuesday afternoon thanks to a warm front moving across northern Illinois. Temperatures were slow to warm initially but have now reached the mid and upper 60s late in the afternoon. A warm front sits close to the state line, expected to remain somewhat stationary through the night. It's possible the front dips south of the state line into northern Illinois before being pulled back north into Wisconsin Wednesday.

Skies will remain mostly cloudy through the night as temperatures dip on either side of 50 degrees. Winds have been somewhat breezy from the southeast throughout most of the afternoon and may increase slightly just before sunset, especially for areas south of Rockford. Skies will remain dry through the early overnight hours, but as increasing winds aloft begin to move closer to Iowa and northern Illinois, scattered showers and thunderstorms are likely to develop. The highest coverage will initially start in northeast Iowa, moving into southern Wisconsin and northern Illinois throughout the morning. The biggest threat with these storms would be hail as they remain north of the warm front and elevated.

There is then a conditional severe weather threat for northern Illinois Wednesday afternoon as an area of low pressure and cold front move in from the west. Dry air moving in behind the warm front would allow enough clearing to take place for instability to grow during the afternoon. If this occurs severe thunderstorms would be possible, developing as early as 2pm.

The Storm Prediction Center did shift the 'slight risk' outlook further north and west to now include locations mainly along and south of Highway 20. If we were to see severe thunderstorms, damaging winds would be our main concern - but the close proximity of the low and fronts would also allow for an isolated tornado threat into the afternoon.

If, however, the low shifts to the south it would not only keep our temperatures from reaching the 60s but also shift the afternoon severe storm threat south with it. Please make sure you're keeping up with the forecast Wednesday, especially if that severe threat grows. Our window for severe storms during the afternoon would be from about 2pm to 8pm.

Once the storm passes cold air will be quick to move in Wednesday night allowing snow showers to develop, and accumulate, through early Thursday. Northwest winds will also increase gusting as high as 45 mph after Midnight. This could impact travel through sunrise before the snow showers shift east mid-morning. Northwest winds will remain strong through 10am, with gusts settling around 25-30 mph during the afternoon.