September, October, and November are the meteorological months considered the autumn season in the US. The official seasonal period varies by regions around the world. But, that besides the point here. I want to explore what we are likely to see (compared to long-term seasonal averages) this autumn across the US and locally.
Well, it looks like the warmer that average pattern over much of the Southwest, Rockies, Midwest, Great Lakes, Mid-Atlantic, and Northeast will be lasting into the fall. The likelihood of warmer than average overall temperatures will continue, especially so in the Upper Midwest and New England. Elsewhere across the country, near average temperatures will likely round out the season once all the months finish and the statistics are tabulated. They'll be heat waves of sorts, and cold waves as well, but the general trend is likely to see fewer cold stretches, that's for sure.
Locally, our average highs range from the 80s in September, the 70s in October, and cooling to the 60’s after the first week or so of November. Short warm periods, and short cold periods will occur, but no excessive long-term pattern will develop to give us a really hot, and certainly a really cold season. Low temperatures average in the 60s during September, with a steady and accelerating rate of average cooling into the 50’s in October and 40s during November.
The warmest September day was 100 degrees in 1925, and the coldest was 42 in 1887. For October, the numbers ranged from 95 in 1986 to 27 in 1962. November extreme temperature ranges were 87 in 1974 to a very chilly 16 in 1950.
A dry fall is likely from the Pacific Northwest east across the far Northern Plains and into northern New England. Look for a little wetter than average conditions across the far Southwest, and from eastern Texas into the low Mississippi Valley. Elsewhere, no clear pattern is emerging at this point. In an average September around here, we see a little under eight inches of rain, but the average drops dramatically to a little less than four inches in October to just over three inches in November. Extremes during these months can be impressive, given the tropical storm season still being very active in September, and occasionally into October as well. We’ve had as much as 23.41 inches of rain in September of 1999, 15.07 inches in October 2005, and 7.87 inches (non-tropical in this case) in November of 1972. Note how big a difference in extremes from the tropical issues of September to the non-tropical extremes of November.
By: George Elliott