Now that we've had a few chilly blasts from the north, and the frost has settled on the pumpkin, it's time to start laying blame for the end of summer and the cold temperatures of autumn. It's Canada's fault.
That's right. Our seemingly friendly neighbors to the north are solely responsible for sending us those daytime highs in the 50s with a solid overcast. Or how about those crisp, sunny mornings when you step outside and the 35-degree air takes your breath away? We can't blame that on Mexico. No, it's Canada.
It's kind of devious how they sneak this stuff across the border, too. They use the jet stream. It's the old conveyor belt of fast winds up around 30,000 feet above the Earth. The jet stream, or steering current, shuttles high and low pressure centers around the world. The lows usually drag cold fronts along with them, bringing clouds and cold air. The highs often bring chilly sunshine this time of year.
Think of the jet stream as the great divider between warm and cold air. The polar regions of the Earth are cold while the equatorial region is warm. A fast current of wind meanders between the two, usually crossing the United States in late fall, winter, and early spring. During the warmer months here in the U.S., the jet stream tends to stay farther north, mainly in south central Canada, as warm air takes over most of the lower 48 states. But come October, the warm air retreats to the southern states and the jet stream starts drifting south. It rarely takes a straight path from coast to coast. It dips and weaves like a roller coaster, transporting warm air north and cold air south, all in an attempt to equalize the balance of temperature between equator and pole. That balance is never achieved, of course, but nature keeps trying.
When the jet stream dips south across the Great Lakes, we get a wake-up chill that reminds us the snow will be flying soon. October is still one of those months when the jet stream can also build back up to our north, ever so briefly, and bath us in a few unseasonably warm days. The warm periods after the first killing frost of fall is called Indian Summer. Yes, we can have more than one Indian Summer in fall, a period so named because the Native Americans would use the late-season warmth to finish harvesting their crops before winter.
So when you hear the weather people start talking about the cool, Canadian air mass approaching, you'll know we're in line for a dip in the jet stream. And those Canadians are just sitting up there laughing. Maybe it's revenge because their hockey teams are moving to the U.S. Or perhaps they're mad about paying more taxes than we do. Whatever the reason, they'll take it out on us until next April. Then they call the jet stream to retreat back to the north.
Watch Vince Condella on Fox 6 Sunday through Thursday at 5, 6 , 9 and 10 p.m. You can see the FOX 6 weather forecast around the clock at www.fox6milwaukee.com
