The Upper Midwest is experiencing some of the coldest weather we've seen in a number of years. With that frigid arctic air over the Great Lakes, the phenomenon "sea smoke" is becoming quite prevalent across much of the unfrozen surface area of the lakes.

NOAA's Great Lakes Environmental Research Laboratory explains in a Facebook post (below) that these "cloud streets" of parallel cumulus clouds developing over the lakes are common in early to mid winter, as cold air moves over the relatively warm water that is mostly open.

As this relatively "warm", moist air raises into the cold, drier air above, the moisture condenses into clouds and "sea smoke". As for the streaky nature of the clouds, the GLERL explains why this happens, saying:

As the rising, warmer air hits the cold air above it, the moisture condenses into cumulus clouds, then cools and sinks on either side. This rising and sinking motion creates parallel cylinders of rotating air that line up in the direction of the prevailing wind (usually out of the northwest). Large temperature contrasts between the surface air and lake water can deliver heavy lake effect snow on the downwind shores of the lakes.

This same phenomenon can lead to lake effect snow on land downwind from the lake, as the relatively "warm" air moves over land, where temperatures are cooler. Being colder air can't hold as much moisture as warmer air, this cooling can lead to snowfall if conditions are right.

Below is an animated GIF from this morning (1/30/19), showing these columns moving with the prevalent wind. People in the Twin Ports area likely saw some sea smoke as recently as yesterday, but the prolonged cold has created a frozen crust of ice covering much of the Lake Superior Bay in the Twin Ports area.

NEXLab - College of DuPage