Another round: Warm temps, rain, then up to 6 inches of snow in forecast for this week

The Detroit News

Stop us if you've heard this one before: Forecasters say a storm is headed toward Michigan this week and it will bring significant precipitation, though it's too early to say where and whether that will be mostly rain or more snow.

Forecasts agree, while Monday continues with the cold snap that brought frigid wind chills and snow Sunday that resulted in major crashes on some Michigan roadways, temperatures will warm into the mid- and upper 40s by Wednesday in central and southeast Michigan.

Along with those temperatures comes rain starting Wednesday afternoon or evening. After that, it's too early to tell when the cold will sweep in and change the rain to freezing rain and/or snow.

"There is reasonable agreement that total rainfall amounts between a half inch and inch will be likely," the National Weather Service says, "with the main forecast uncertainty involving how much wintry (precipitation) falls on the cold side of this frontal system."

A system currently off the Pacific Northwest is expected to converge with another system that is out over the Pacific, according to the weather service, and observation over the coming days will help form a more detailed picture.

The uncertainty brings to mind a storm earlier this month that forecasters had predicted could lead to historic snowfall totals over two days in Metro Detroit and southeast Michigan. Instead, warmer temperatures Feb. 2 meant mainly rain early and held down snow totals except for areas in extreme southeast Michigan.

But even rain on snow and frozen ground can have dire consequences. 

"... with this amount of rainfall onto frozen ground, runoff will be efficient," the weather service says. "So rises on area rivers is expected." Additionally, rain will make it difficult to pretreat road surfaces and quickly dropping temperatures could lead to icy roads.

Right now, the forecast:

► National Weather Service for Metro Detroit: 

Wednesday: Breezy. Not as cool. Cloudy. A 50% chance of rain in the afternoon. Highs in the upper 40s. South winds 15 to 25 mph. 

Wednesday night: Rain in the evening, then possibly mixing with snow and freezing rain after midnight. Lows in the upper 20s. Chance of precipitation near 100%.

Thursday: Colder. Rain and snow, possibly mixed with freezing rain in the morning, then snow in the afternoon. Highs in the mid 30s. Chance of precipitation 90%.

Thursday night: Much colder. Cloudy with a 30 percent chance of snow in the evening, then partly cloudy after midnight. Lows around 7. Wind chill readings 4 below to 6 above zero.

Accuweather says 3 to 6 inches are possible Thursday and Thursday night.

► Accuweather:

Wednesday: Cloudy and breezy. High of 50. Chance of rain 25%.

Wednesday night: Rain; breezy in the evening. Low of 45. Chance of rain near 100%.

Thursday: Breezy with rain mixing with snow, sleet, 1-3", then colder; roads and sidewalks could become slippery as temperatures fall. Morning high of 45 as temperatures drop. 

Thursday night: Early snow, 1-2", breezy; mostly cloudy and much colder; storm total 3-6"; untreated roads will be snow packed and slippery.

► The Weather Channel:

Wednesday: Mostly cloudy and windy with showers developing later in the day. High 48 degrees. Winds SSW at 20 to 30 mph. Chance of rain 40%. Higher wind gusts possible.

Wednesday night: Cloudy with periods of rain. Low 39. Winds SW at 15 to 25 mph. Chance of rain 100%. Rainfall around a half an inch.

Thursday: Watching a potential winter storm. Cloudy with rain and snow in the morning, becoming all snow in the afternoon. Morning high of 44 with temps falling to near 25. Winds N at 10 to 20 mph. Chance of rain 90%. Snow accumulating 3 to 5 inches.

Thursday night: Watching a potential winter storm. Snow showers early. Breaks in the overcast later. Low near 10F. Winds NNW at 10 to 20 mph. Chance of snow 60%. Snow accumulations less than one inch.

The Weather Channel predicts up to 6 inches of snow by Thursday night in Metro Detroit.