The October Flip: what a month’s weather can tell you about long-term forecasts

Thirty-one days ago we were entering one of the hottest periods on record in October. The first 15 days of the month averaged 72ºF (6.3 degrees above average): the fifth warmest on record in Huntsville. Then the pattern changed drastically from the 16th through the end of the month!

The last half of the month averaged about 3ºF below average, and that big cool down brought October’s over-all average down to +1.4ºF: not far from ‘normal.’

Why is information like that important?

See NOAA’s seasonal outlook; it gives us odds of being above or below ‘normal’ with respect to temperature and precipitation.

That’s guidance; it cannot tell you if there will be a record low, a snow storm, a severe weather outbreak, or a record high. It’s pattern recognition for a season.  So, if the winter season ends up being 1ºF or 2ºF above average (December, January, February), the guidance was good.

A lot can happen to get to that point, though.  Take October for example…

If all you knew about October is that the average temperature was 1.4ºF above ‘normal,’ you’d never know we had one day with a high at 90ºF and another day at 50ºF.

This map of the monthly temperature anomaly (difference from the 30-year average) on the surface says, wow, what a hot October!

October 2017 Temperature Anomaly

It was warm enough for half the month to tip the colors toward the warm scale, but it was cold enough on the back end to bring us down nearly five full degrees.

Does this tell us anything about what November will be like? Not really. The next week to ten days looks warmer than average, but there’s some cold out there ready to come south by the middle of the month. The question is just how cold will it get this far south?

Will it snow? Will we have severe weather? Weather ‘events’ like that fly below the monthly outlook ‘radar.’

Even a 46-day outlook from an ensemble like this paints too broad a picture!

We’d usually expect some storms but not snow in November; however, it has happened before! Huntsville’s earliest recorded ‘measurable’ snowfall happened on November 2, 1966: four inches. Just in case you’re wondering, it usually doesn’t snow enough to measure (if it does it at all) until January around here.

Need some specifics about the weekend or next week? They’re always online at WHNT.com/Weather and in the “Daily Forecast” section on Live Alert 19!

-Jason
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