DETROIT – Before getting to the forecast, let me offer a quick explanation about what's going on this week.
As we've explained on the air, a trough (or dip) in the jet stream has developed over the Great Lakes, and it's going to be a while before this pattern relaxes. The actual upper level low pressure area is well north of Michigan in Ontario, and the image I want you to picture is a bicycle wheel. The center of the wheel is where the upper level low is, and as the wheel rotates, periodic spokes (weak lines of low pressure) cross our state. When one of those spokes coincides with the warmest part of the day, scattered showers, and even a couple of thunderstorms, are possible.
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Shower coverage is dependent upon how strong the spoke of low pressure is, as well as its timing with the afternoon heat. If one passes through at 8 a.m., it probably won't trigger more than a few clouds; if one passes through, however, at 6 p.m., then we can expect increased shower activity. In general, though, they pop up mid-afternoon, and quickly diminish early evening as cooling begins. This is the pattern we'll be in through the weekend, and keep in mind that most of each day will be dry, and there will be some days that you get no rain at all. But the risk is there late each afternoon.
With that being said, the forecast is pretty simple:
Wednesday through Sunday daytime: Partly cloudy with scattered afternoon showers each day -- generally after 2 p.m. Highs starting in the mid 70s, and gradually rising to near 80 by the end of the weekend.
Wednesday through Sunday nighttime: Any showers that do develop rapidly diminish each evening, then becoming partly cloudy. Lows starting in the mid 50s, and gradually rising to near 60 by the end of the weekend.
This means great sleeping weather all week long!