This is not a drill.

Temperatures are expected to drop to near freezing overnight, turning a persistent May rain into a significant winter-like storm, with 4-12 inches of new snow possible by Thursday morning in some areas of the Northland.

The National Weather Service in Duluth issued a winter storm warning from 7 p.m. Wednesday to 10 a.m. Thursday for areas near Lake Superior, with 4-8 inches of wind-whipped snow expected. As much as 12 inches could fall in higher elevations away from the lake.

"There is the potential for up to a foot of snow in some isolated higher terrain'' around the lake, said Jonathon Wolfe, a senior meteorologist with the Weather Service in Duluth.

Wolfe said slippery roads for the Thursday morning commute, low visibility overnight and possible power outages will be the major impacts of the storm.

A winter weather advisory is posted for other parts of the Northland with 1-5 inches expected across a wide area.

Northeast winds overnight will gust to 40 mph at the head of Lake Superior and a gale warning has been issued for the open waters of the big lake.

How much snow falls overnight will depend on how long temperatures stay near or below the freezing mark.

Whatever snow does accumulate, however, won't last too long. High temperatures Thursday will be in the upper 40s with highs over the weekend approaching 60 degrees.

The early forecast for the Saturday Minnesota fishing opener calls for highs in the mid-to-upper 50s but with a good chance of rain in the afternoon and breezy winds out of the northeast.