Thunder, rain, snow all possible beginning Wednesday; parts of Milwaukee metro, as well as Green Bay, could see 2 to 5 inches of snow

A powerful spring storm is forecast to bring a mess of weather, including accumulating snow, to much of Wisconsin -- including northern and western portions of the Milwaukee metro area -- overnight Wednesday and continuing into Thursday morning, forecasters say.

The storm system will move across Wisconsin and will likely transition from rain showers and possible thunderstorms to snow by the time it scoots east of the state on Thursday.

"We're in the spring. This is our transition period where Mother Nature is going to throw pretty much everything at us," said Rebecca Hansen, a National Weather Service meteorologist in Sullivan.  

More:Ice shove plows into home on west shore of Lake Winnebago

In the Milwaukee metro, Waukesha, Ozaukee and Washington counties have been placed in a winter weather advisory for accumulating snow. The advisory took effect at 4 a.m. on Thursday and continues until noon on Thursday. 

The advisory also covers Fond du Lac, Sheboygan, Sauk, Columbia, Dodge, Iowa, Dane, Jefferson, Marquette and Green Lake counties.

The early morning snow caused slippery driving conditions on the western edge of Milwaukee County into Waukesha County and north to Saukville, according to the state Department of Transportation's road condition tracking map. Before 7 a.m., the DOT reported isolated crashes on Interstates 94, 43 and 41/45 but no road closures. 

In southern Wisconsin, the weather service says it expects snow accumulations of 2 to 5 inches northwest of a line from Dodgeville to Madison to western Sheboygan County, with 1 to 3 inches falling elsewhere in the areas under the advisory.

"A period of moderate to heavy snow is expected during the morning commute," on Thursday across southern Wisconsin, the weather service said in a statement. "Slushy accumulations may cause hazardous travel conditions."

Milwaukee is not included in the advisory.

"Sheboygan, West Bend, Fond du Lac, Beaver Dam, those are the areas where we are expecting the highest accumulation in southern Wisconsin," said J.J. Wood, a weather service meteorologist in Sullivan. 

"Milwaukee, Racine and Kenosha will have lighter amounts. Temperatures are going to be a bit warmer," along Lake Michigan, Wood added. "So, there is some question as to how much of an impact there will be for Milwaukee County itself and areas further to the south."

That could change as forecasters watch the storm's progression overnight.

"You could see more counties added to the advisory later if we think that the areas further south and east are going to get more snow," Wood said. "At this time, we're still unsure, so that's why (Milwaukee, Racine, Kenosha and counties along the Illinois border) aren't in the advisory." 

As of late Wednesday afternoon, Milwaukee was forecast to receive around and inch of snow.

Meanwhile, depending where you are in the state, you might see and hear lightning and thunder on Wednesday night followed by accumulating snow early Thursday.

The key is how fast the cold air arrives on the backside of the storm and changes everything over to snow, Hansen said.

Accumulating snow for Green Bay, Appleton, Stevens Point

In northeast Wisconsin, the weather service has issued a winter weather advisory for 2 to 4 inches of snow. The advisory begins at 3 a.m. Thursday and continues until noon Thursday for Outagamie, Brown, Winnebago, Manitowoc, Portage, Menominee, Oconto, Door, Shawano, Waupaca, Kewaunee, Waushara, Calumet and Marinette counties.

Some of the cities covered by the advisory include Oshkosh, Appleton, Green Bay, Stevens Point, Neenah, New London, Keshena, Brillion, Clintonville, Manitowoc, Waupaca, Sturgeon Bay, Peshtigo, Menasha, Two Rivers, Shawano, Sobieski, New Holstein, Wautoma and Kewaunee.

"Rain will change to freezing rain and sleet, and then to snow," the weather service in Green Bay said in a statement. "The snow could be heavy at times. Snow accumulations of 2 to 4 inches are expected and a small ice accumulation. Winds could gust to 35 mph."

Far northwest Wisconsin is also under a winter weather advisory.

The accumulating snow could cause some issues on roads and highways in the state by early Thursday morning. 

"It's something to keep an eye on, especially going into tomorrow morning before you head out the door," Hansen said. 

All of this weather is part of a storm system that is expected to bring a widespread significant severe weather outbreak to areas of the South and central Gulf Coast, Hansen said.

"It's related. We're more on the northern part of the system. It's all tied together," Hansen said.

No severe weather is expected in Wisconsin. 

Rain/snow line will move northwest to southeast

Across Wisconsin, the line where rain changes over to snow will move from northwest to southeast.

"So we're going to see a transition to snow for Thursday morning," Hansen said. 

If there is a faster transition to snow, there could be more accumulation.

Wausau and Stevens Point may also see thunderstorms before everything switches to snow overnight. Some freezing rain is also possible. 

"There is a lot of uncertainty as far as accumulations go, due to the complexity of the storm, initially warm ground and how quickly the precipitation changes from rain to freezing rain, sleet and snow," the weather service in Green Bay said in a statement.

Also, northwest to north winds will gust to 30 to 40 mph late Wednesday, and could cause ice shoves on the Bay of Green Bay and Lake Winnebago.

Whether the mess creates travel problems remains to be seen.

"Be aware. Take it slow," Hansen said. "You might need a little bit more time to get around, especially if you are driving further north," on Thursday.

Contact Joe Taschler at (414) 224-2554 or jtaschler@gannett.com. Follow him on Twitter at @JoeTaschler or Facebook at facebook.com/joe.taschler.1.