The much-needed rain at the end of September certainly wasn’t enough to save New England from another dry month.
Boston and Providence finished the month around 2.5 inches of rain below normal; Worcester and Hartford around an inch and a half below normal; and much of northern New England 2.5 to 3 inches drier than normal!
The headline of our First Alert October monthly forecast is, unfortunately, very similar: Dry times ahead.
Seasonal drought through the summer isn’t all that uncommon for New England, but often we can count on fall rain to lift us out of drought. While that may happen in November, it doesn’t look like October will deliver enough rain to do that.
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In fact, it’s concerning that my expectation for the month of October isn’t just dry in New England, but dry for most of the United States except Florida and the deep Southeast. As of Thursday, most of the western United States was in drought with recurring dangerous fire weather conditions, and a lack of October rain won’t help either of those factors out west, let alone our water table here at home.
The root of the problem comes as the eastern United States jet stream “trough” – a dip in the jet stream that is currently allowing for cool air and disturbances – will retreat into Canada as the jet stream rides north and a large “ridge” of high pressure (a dome of relatively warm and dry air) takes over. A large ridge over the nation sends Gulf of Mexico moisture deflected across Florida and into the Atlantic, while simultaneously deflecting Pacific moisture into Alaska and Western Canada.
Under the ridge of high pressure, the mostly dry weather will also aid in relatively warm temperatures for a large swath of above-normal temperatures averaged over the month, again with the possible exception of the southeast United States.
Of course, here in New England, “warmer than normal” needs to come with tempered expectations: Boston’s normal high temperature for the month of October is 61, down some 11 degrees from September’s normal high temperature, so even running a couple degrees above normal would be noteworthy from a weather standpoint…but still feel like fall.
One of the most common questions we hear is: What does this mean for the winter? While it’s too early to feel confident on a winter forecast, I can tell you the weather almost always finds a way to balance out in New England.
When our droughts carry into October, we almost always can count on precipitation to pick up markedly in November and December, be it as rain or snow. So, historically this means we may need to be in the mindset for a messy late fall and early winter, but we’ll get a better handle on that the deeper we get into November.