A benefit to Michigan's heatwave? The Great Lakes levels are actually falling

Nearing the end of an unbearable heatwave might bring some relief, but a warning: more 90-degree days are on the way.

But there still is a silver lining to all this sweltering heat. It just won't be found inland. Instead, one's perspective must be cast a little further beyond the horizon; preferably on one of the five Great Lakes. For the first time in a while, lake levels are measuring lower than their forecasted height. 

A combination of below-average precipitation and exceedingly-high temperatures have served as an effective duo for trimming a few inches off the historically high levels, much to the delight for communities along the Michigan coast.

The forecasted lake levels for 2020 didn't start off too good in January. Coming off a brutally-wet 2019 that saw record levels in three lakes and near-highs in the other three, this year's forecast predicted more of the same. Although because it was Lakes Michigan, Huron, and St. Clair predicted to exceed past highs, residents around Michigan were concerned about potential erosion and flooding.

As it stands right now, Lakes Michigan and Huron broke their lake level height in June by about four-and-a-half inches, which is approximately four feet 10 inches above the average height - a measurement that shouldn't be disregarded. However, in February, the forecasted high for June was four feet 11 inches for Lakes Michigan and Huron. 

That's right, the lakes have fallen a whole inch from their expected highs. It may not seem like a lot, but amid the cyclical increase of lake levels that happens every year, any relief can help. In Lake St. Clair, the Army Corps projections have taken a sharp turn down from what was forecasted in February. If forecasted levels remain the same, we won't be setting any more records in the Metro Detroit lake. That's also the case in Lake Erie.

So what happened to our Great Lakes extremes becoming slightly less extreme? First, a science lesson.

When temperatures increase, so does the rate of evaporation. Think about boiling a pot of water: the more you turn up the heat, the faster the water will evaporate. This cycle helps feed the atmosphere with more water vapor, which then comes down as rain and snow. As atmospheric temperatures continue to warm due to an increase in greenhouse gases like carbon dioxide and methane, so does it's capacity for holding more moisture. 

But that moisture has to go somewhere, and when it does it falls in increasingly strong rain and snow events. Not all of that precipitation is distributed evenly, however. Some places could experience wetter winters and springs, while some will experience drier ones. In the case of the Midwest, it's been heavily on the wetter side. 

The last 60 months have been the wettest five years on record for the Great Lakes Basin. Precipitation falling in more abundance has been one of the reasons the state has seen 100-year and 500-year flood events. 

But narrowing the window of time for measuring precipitation tells a different story. The amount of rain that's fallen on Michigan has been almost 2 inches less than the average since June 1. Additionally, eight straight days of 90-degree weather has contributed to evaporation rates that have helped drive down lake levels.

What does this mean in the grand scheme of things? Probably not a lot from the naked eye. And concerns of erosion are still high for many residents on the west side of the state. 

But a little good news can't hurt.