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Don Paul: Turn off the AC – autumn temps are here

It was only a week ago when we were dealing with record warmth and temperatures in the 80s. I thought about turning a window unit on upstairs a couple of those days, but didn’t succumb to summer’s last October gasp.

The heat’s done. We have transitioned over into an autumnal pattern. This doesn’t mean we won’t have any more mild days. What it does mean is average- to below-average temperatures will occur more often than above-average temperatures for a couple of weeks.

For example, here is what the European ensemble is showing in the upper air for Sunday. There is a warm ridge in the west and a cold trough in the east, which will probably result in some lake-effect rain and snow showers on a northwest flow. A northwest flow favors more of this spotty lake-effect to focus on the hilly terrain well south, and off Lake Ontario well to the east.

Most times, especially in a transitional season like autumn, such deep, cold troughs don’t stay all that long. The same European ensemble shows some moderation by middle to late next week as the trough weakens and moves out.

Agreement between models and ensembles is a key to forecast confidence. When there is major disagreement, forecast confidence usually goes out the window. In this case, the American ensemble is lined up nicely with the European for Sunday, even though they run off different equations and methodologies.

The same goes with the American model for the middle to late next week pattern as cold moves out and moderation moves in.

Late in the month, there is also pretty good agreement in the ensembles on a colder finish. Note: the amplitude of patterns look flatter late in an ensemble run because the many individual model runs which make up an ensemble tend to spread out more for the same reason weather forecasts are less reliable further out in time. But when this somewhat flatter extended range ensemble still show those troughs and ridges, with the colder blue shading in the troughs in similar locations, flatter looking or not, that’s something to keep an eye on. Here are the American and the Canadian models.

I have seen speculation from a few scholarly meteorologists that this late October pattern may favor the development of an East Coast storm which could bring coastal rain and interior snow. I mention this because such speculation is coming from sources I generally respect. However, over my many decades of work I’ve come to realize models and ensembles project temperatures with far better verification two weeks out in time than they project precipitation. There are such hints, but even if such an East Coast storm develops, its track could easily be too far to the east to have much of an impact in Western New York. On the air, I’d probably just say “it’s something we’ll be keeping an eye on.”

The general idea about the pattern is reflected in this animated ensemble from the National Centers for Environmental Prediction, which I prefer to simply call NWS HQ. Last week we had a well-predicted big, warm ridge during that heat dominating the middle Atlantic and northeast United States. In the NWS HQ's ensemble animation, no such ridge appears in the east. There are ups and downs, but the general trend is for the colder troughs to dominate our part of the continent more often than not over the next couple of weeks.

This does not necessarily mean much for how November, December and January are going to go. In fact, in my experience, seldom does a prevailing October pattern survive into the winter. Again, this is a transitional season. As for now, the extended range European ensemble is bullish on a colder-than-average winter for the eastern U.S. The U.S. Climate Forecast System ensemble (which has a lower verification score than the European, in general) shows quite the opposite, with virtually no part of the U.S. having below average temperatures.

As for my thoughts, I have seen lay press stories about how a developing El Nino will mean a milder winter. The type and location of this winter’s El Nino tell a different story to many meteorologists, including me.

Buffalo Niagara's winter weather depends on a lot more than El Niño

If you don’t have time to read the whole story, the first two short paragraphs are the bottom line. IF we have a milder winter, it will have little to do with the coming weaker El Nino.

In the meantime, here are the probabilities for above or below temperatures in the 6- to 14-day range and the 8- to 14-day range from the NWS Climate Prediction Center.

It goes almost without saying I wouldn’t have included these last two outlooks if I didn’t agree with them. I have enough chances to make my own mistakes … am I right people?

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