Winter Weather Advisory in effect Friday

ROCKFORD, Ill. (WIFR) - In a snow season which has gotten off to a somewhat lackluster start, snow enthusiasts have been hoping for a change in fortune, and for some, that’s exactly what’s about to happen.

With our incoming storm track taking a slight southerly jaunt, it places more of the Stateline in a favorable region for accumulating snow. With that said, though, not all of us will see snow stick to the ground, and the situation remains a bit fluid, even just hours away from precipitation’s arrival.

The National Weather Service has issued a Winter Weather Advisory beginning and midnight Friday and continuing through the late afternoon or early evening hours for the northernmost tier of counties in Illinois and all three of our southern Wisconsin counties.

Winter Weather Advisories are in effect for extreme northern Illinois and all of southern... — Winter Weather Advisories are in effect for extreme northern Illinois and all of southern Wisconsin.(Mark Henderson, WIFR)

Now, let’s dive into the specifics of the storm though the lens of Thursday evening’s most recent model runs. Precipitation looks to commence between midnight at 2:00am, first in the southwest, then gradually lifting northeast. Initially, precipitation looks to start as rain over the vast majority of the region, but extremely close attention will need to be paid to our temperatures. As of 10:00pm, temperatures were below freezing across the entire Stateline. We’re banking on the return of clouds allowing temperatures to warm back above freezing before the rain begins to fall. Should that not be the case, concerns for icy roads would mount quickly.

Rain or freezing rain appear to be the initial form of precipitation, with snow over Wisconsin. — Rain or freezing rain appear to be the initial form of precipitation, with snow over Wisconsin.(Mark Henderson, WIFR)

Latest model guidance suggests that precipitation may remain as rain over the vast majority of northern Illinois a bit longer than initially expected, with a transition to snow taking place over much of southern Wisconsin.

Precipitation may remain as rain for much of the area through 5:00am. — Precipitation may remain as rain for much of the area through 5:00am.(Mark Henderson, WIFR)

As we reach the all-important morning commute period, things may become a bit more precarious over parts of the area. Along and north of US-20, precipitation is likely to have changed over to all snow, while south of US-20, a mix of rain, snow, and sleet is expected. South of Interstate 88, precipitation remains as all rain.

Along and north of US-20, snow will be falling, along and south of US-20, a wintry mix is more... — Along and north of US-20, snow will be falling, along and south of US-20, a wintry mix is more likely.(Mark Henderson, WIFR)

A period of 2-3 hours of snow remains likely for far northern Illinois, while southern Wisconsin’s window for snow is considerably longer. However, by late in the morning, some spots may be seeing a transition back over to rain.

Snow is to continue over much of southern Wisconsin late Friday morning, perhaps blending with... — Snow is to continue over much of southern Wisconsin late Friday morning, perhaps blending with sleet, rain, or freezing rain in northern Illinois.(Mark Henderson, WIFR)

While precipitation won’t be entirely finished by 2:00pm, it will most certainly be winding down. Still, a few light rain or snow showers may linger, though no subsequent accumulations of any consequence are in the cards at this point.

Sprinkles or flurries may linger through the early afternoon, though the bulk of the... — Sprinkles or flurries may linger through the early afternoon, though the bulk of the precipitation will be winding down.(Mark Henderson, WIFR)

Regarding accumulations, we’ve slightly amended our forecast from our early evening newscasts. The net result has been to trim the accumulations down a smidge over northern Illinois, and to bump them up a bit over southern Wisconsin. Because of the limited timeframe for precipitation to fall as snow in northern Illinois, we’re now calling for 1 to 3 inches, with lighter amounts as you go south of Interstate 88. Areas closer to the Wisconsin border may see an isolated 4 inch total, but that’s far from guaranteed. On the other side of the ledger, we’ve bumped numbers up over most of southern Wisconsin to 3 to 5 inches, with the highest amounts to fall along with I-94 corridor between Madison and Milwaukee’s northwestern suburbs.

Snowfall amounts are to be heavier north and lighter to the south. — Snowfall amounts are to be heavier north and lighter to the south.(Mark Henderson, WIFR)

A final note of caution, while this forecast represents our very latest thoughts on the storm’s evolution, this is NOT set in stone. A shift of 5-10 miles or a temperature rise or fall of even one degree could have dramatic impacts on the end result. This remains a fluid situation, and one you can assure we’re monitoring closely and constantly.

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