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Coldest air of the season arrives next week

Posted at 9:49 AM, Oct 18, 2017
and last updated 2017-10-18 09:49:56-04

WEST MICHIGAN- We've had our fair share of ups and downs with respect to temperature during this fall season so far, but we haven't seen any incredibly cold air like we're used to at this point in the season.  Our average high right now is 60 and our average low is around 40.  Have we seen much of that so far this year?  Not really.  In fact, it was similar to last October as well, although we had more cool days to start, and much colder conditions to finish the month.

A much cooler air mass is developing in Canada at the moment.  That's where we'll look for our big change to arrive from.  Sure, you may think Canada is always cold this time of the year, but I'll use Winnipeg as an example, as it was 57 when I took a snapshot of the temperatures around 8 in the morning.

The jet stream is one of the factors that drives the direction most of our weather systems move.  While we talk about high pressure and fair weather, that's what you're seeing under this warmer portion of the jet stream.  A strong high pressure center will develop and the western half of the United States will be warm and dry.  Our half of the United States will be much cooler, and a little bit more wet.  This is associated with a strong low pressure center and a dip in the jet stream which allows for that colder Canadian air mass to filter in to the Great Lakes region.

That's when we'll feel that much cooler air by Tuesday into Wednesday.  Will it be freezing cold? Probably not.  Afternoon highs will be in the 40s and low 50s and it will be cloudy with a few showers.  I will say that the potential for our first frost is there either Tuesday or Wednesday morning as overnight lows dip down into the 30s area wide, but we'll have to monitor that more closely once that time comes.