There goes that jet stream again, pumping up warm air like a weightlifter and making it feel like summer again in metro Detroit. We talk about the "jet steam" often on TV, but if you're not quite sure what it is and does, give me three minutes.
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Think of the jet stream as a river of air high up in the atmosphere, usually 5 to 8 miles above us in southeast Michigan. It snakes around the globe from west to east all year long, but it's mostly north of us in the summer and farther south in the winter.
It's there because of temperature differences; it's colder to the north and warmer to the south, and the jet stream separates these opposing masses of air. The jet gets stronger, meaning its winds move faster, during the colder months because the temperature difference gets bigger. So the first reason to pay attention to it is because it separates cold air from warm air.
The jet stream is also called the "storm track," which is a great name, because the other reason to watch it is because it guides storms. A fast jet stream can move storms fast. And when you see us show you the jet stream, when south of the jet in an area that looks like an upside down "U," it's usually warmer than average and not stormy. When you see the part of the jet that looks like a "U," which is in the western US today, stormy weather is often in the right-hand side of the U-shaped dip, and it's colder. today it's snowing in a lot of the northern Rockies.
By the way, the jet stream wasn't discovered until bomber jets in WWII reported that it took a lot more time and fuel to go west to their targets in Japan than it did to get back to their bases when flying east. The "river of air" had winds to nearly 200 mph, pushing them home much faster when that wind was at their backs.
We'll be talking about the jet stream a lot more as we head into the colder months and it gets more active. Here's hoping you've got a better idea now what we're blabbing about.