A Unique Phenomenon Flips Lake Temperatures

Posted at 8:48 AM, Jul 25, 2013
and last updated 2013-07-25 09:57:40-04

072513upwellingWEST MICHIGAN — A unique but common phenomenon occurred in Lake Michigan this week.

The cold front which moved through this week brought gusty north winds around 30 to 35 miles per hour Tuesday afternoon, allowing for upwelling to occur. Water temperatures dropped from the low 70s to 40s in some areas in less than 18 hours. The Ludington buoy recorded a drop from 71 degrees to 42 degrees in less than 18 hours.

Upwelling occurs when strong winds gust perpendicular to shore combined with the Coriolis effect (Earth’s rotation). This combination allows the lake water to flip-flop due to density differences. As a result, the warm surface waters displace the cool, deep waters, dropping lake surface temperatures significantly.

Another cold front will drop through this Friday, bringing cooler temperatures for the weekend along with rain chances. Rain chances increase through the afternoon and evening Friday as the cold front moves across the state. Heavy rain and gusty winds could be possible as the front moves through. However, severe weather is not expected.

Temperatures behind the front will drop back into the upper 60s and low 70s by Sunday afternoon. The cooler weather however will be short-lived as temperatures warm back to around average by mid-week.

Follow the changes of the FOX 17 weather page.