DETROIT – Everything is on track for the upcoming weekend storm. Rain is moving northward into the region, but areas getting rain this morning are above freezing and have avoided major ice problems so far.
This storm promises to bring a high amount of moisture with it. A flood watch has already been issued for Wayne, Monroe, and Lenawee Counties. Those areas may get an inch of rain, which, combined with melting snow and a frozen ground that cannot absorb water like it can in the summer, will cause considerable runoff and flooding potential.
Farther north is where the forecast gets very complicated. As rain moves northward, colder air is sliding south. As a result, surface temperatures well north of 8 Mile should eventually drop to or below freezing this afternoon and evening. When the rain falls into that below-freezing layer of air, it will freeze onto roads, sidewalks, trees, mailboxes and cars (if parked outside, of course).
Given the amount of rain heading towards the area, it's possible that over a quarter inch of ice could accumulate in the north, which has the potential to bring down tree limbs and cause power outages. Adding to the problem will be the wind overnight and tomorrow morning, which should increase to 10 to 15 mph. The most significant icing will likely be north and west of a line extending from Mount Clemens through Troy to Pontiac, then curling down toward southwest Oakland County, northwest Washtenaw County, and southwest from there.
To highlight the potential for this scenario to play out, an ice storm warning has been issued for all counties except for the flood watch counties listed above and Washtenaw County, where a winter weather advisory is in effect (it likely will not get warning criteria ice).The rest of Wayne, Lenawee and Monroe Counties should see plenty of rain and the most likely problem is flooding.
Snow is not on the weekend forecast whatsoever. The best chance to get any snow would be Sunday night, possibly Monday, as the lake effect machine gets cranked up to the west. Keep in mind that temperatures will fall sharply Sunday night, so standing water will freeze. Parking lots and other areas will be covered with ice by Monday morning.