September will bring cooler than average temperatures

Posted at 3:04 PM, Aug 31, 2020
and last updated 2020-08-31 15:04:56-04

WEST MICHIGAN — Our summer here in West Michigan has been a fairly hot enjoyable one weatherwise. While we've experienced a view bouts of severe weather, we've had very few cool days and frankly, we are above normal in the number of 90 degrees days in many spots. That said, the really hot conditions may have come to an end...perhaps for the season. Here's why.

There are a team of meteorologists and climatologists who work for NOAA and the Climate Prediction Center (CPC). Their job is to come up with weekly, monthly, and longer range forecasts for both temperature and precipitation. It's their job, it's what they do. CPC is saying the next two to three weeks of September will likely be cooler-than-average. That doesn't mean we won't see an 80 degree day here or there, but overall (on average), we expect cooler temperatures. Keep in mind normal highs for this time of year have us in the upper 70s. As we get further into September, it gets harder to reach 90 or better. It doesn't mean we can't, but it becomes less likely.

The scientists look at the upper level jetstream, its movement and configuration, and the interaction of ocean currents and temperatures that actually drive the trough and ridge pattern in the jetstream. The look for trends...something that will gravitate toward a certain pattern, or at least will stay in place for a while.

Take a look at our first graphic below. It's the 6 to 10 day temperature outlook from CPC.

It's clear to see the huge blue blob over much of the country. Alot of the area remains in a 60 to 70 percent chance of below normal temperatures from September 5 through 9. That means the Labor Day weekend too. Precipitation during that same time frame can be seen in the image below. The green over the eastern third of the nation means about a 40 to 50 percent chance of above normal precipitation. So perhaps, more rain than normal.

Take a look at the CPC 8 to 14 day temperature outlook below from September 7 through 13. Again, lots of blue...continued below normal temperature chances...about a 60 to 70 percent chance.

The next image below also shows the precipitation chances during that same time frame. When we stretch the time out just a little bit more, the precipitation trend becomes more toward normal or slightly above.

The last graphic from CPC is the three to four week temperature trend from September 12 through 25. Again, chances remain for temperatures to be slightly below normal. Keep in mind that during these weeks, we will likely see some warm days and 80 degree days, but overall it will trend cooler.

One other thing to note is the dryness we've had. We had heavy rain last week in some areas, but parts of southern lower Michigan are still running a drought. See drought monitor graphic below.


Nobody reading this should write off summer as being over. While we may be trending a bit cooler over the next few weeks, I'm confident we still have some fabulous weather ahead before it turns colder as the season changes. I'm a boater! I would expect many more terrific boating, fishing, and swimming days ahead, but time is growing short. Get out and enjoy while you can, as we welcome in September first tomorrow.

Get the complete West Michigan forecast at