So tell me…does this upcoming cold frontal passage mean anything for the upcoming winter?

The short answer is “probably not”. This type of weather system is very typical for early October, a result of upstream tropical forcing that translates into ridging over western North America (+PNA) that could last for a week or so. A storm that sets up around or just below the Aleutian Islands pumps up a ridge, while a trough and cold pool in Nunavut AR and Hudson Bay is pushed south and east into the lower 48 states.

The near term and medium range will see a thunderstorm threat emerge along the leading edge of the energy and cool polar air mass. This should be apparent over the northern Intermountain Region, then drop through the Great Plains into Texas by the middle of next week. I suspect that the numerical models are not giving enough respect to this feature in the Midwest and Northeast next Thursday and Friday. With a neutral to negative tilt 500MB trough, there could be a lot of intense convection as the cooler values arrive.

In any event, the polar regime that tales over in the middle and eastern sections of the USA next weekend is not in itself a big deal. The cP air mass will shut down air conditioners and fans, but also enable more outdoor activities. The question we face is this: does the amplified upper air pattern come back as we go through October into November? It might, if only because the warming of the western equatorial Pacific Ocean may favor increased -EPO and +PNA styled ridge formation. In that case, the most favored route of air travel will be from northern Canada into the eastern two-thirds of North America. But we will not know if that is the dominant scenario until the third week of October. Which is when I construct my DJFM (winter) outlook.

Have a wonderful weekend, everyone!

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