This morning’s low temperatures are the coldest of the fall season in many places and this comes on the heels of Tuesday’s high temperature of 45, the chilliest day we’ve seen since April 9th. While it’s cold this morning, it’s been a milder November this year and you have likely noticed the landscape doesn’t even look as wintry as it typical would into the second half of November.
The map below (courtesy of WeatherBell Analytics) shows just how warm the eastern half of the country has been this month thus far. The key on the right indicates how many degrees above average a given area has been in November.
By this point in 2014, November had already recorded 11 days below average. This meant last year, many plants and our lawns had transitioned closer to their winter dormant state of existence. Tuesday marked only the second day of below average temperatures this month.
El Nino is going to be a major player in our weather this winter, and, already, its fingerprint is likely on the warm and dry November. Years with a strong El Nino often see the winter start late. The good news for winter enthusiasts is that even a warmer-than-average December will still be cold enough to make snow across ski country. El Nino years are something southern New Englanders are accustomed to.
Strong Jet Stream South
In an El Nino year, the southern jet stream becomes stronger than average. This brings more moisture and-cooler-than-average temperatures across the southern tier of the United States. This means your friends who winter in Florida will likely experience a wetter and cooler winter than they have enjoyed the past several.
El Nino typically keeps New England, especially northern New England, warmer and drier than average. This translates into less cold and fewer snowstorms. Remember, these are averages. Each El Nino is different, and its impacts across the United States are different depending on other factors, such as temperatures in the Atlantic Ocean, off the West Coast and thunderstorms in the tropics.
El Nino Is Warm Ocean Water
While it might seem El Nino is a type of storm, it’s not. El Nino is simply part of the cycle of warming and cooling of the waters off the South American coastline. The water temperatures there oscillate between cold, neutral, and warm at fairly predictable intervals. This year’s El Nino will likely peak in the coming month, but linger through February.
There’s a tight relationship between the water temperatures and the flow of wind above it. In these El Nino years, the trade winds can actually flip direction, which would have ripple effects across the globe, especially in the tropical areas.
One of the impacts of a typical El Nino is on our moisture. Rainfall, while not as heavy as last November, was three times what we have seen so far this year. The warm and dry conditions lately have allowed some plants to continue growing or even bloom again.
You might ask if there’s anything you should do to your plants if they are exhibiting unusual behavior. The quick answer is no, but with a few exceptions. If you planted anything this fall, be sure to give it a good soaking if the ground becomes dry. In spite of some rain in the forecast tomorrow, I still don’t see any widespread wet periods on the way.
All El Nino years have their own unique patterns. While the odds favor fewer arctic outbreaks than last winter, it can still be quite stormy. I’ll have more updates on the winter forecast later this month.