Chief Meteorologist David Aldrich's Winter Weather Outlook
Well, winter is almost here. And in some cases, the bitter cold air has already made its presence known in East Tennessee this autumn. Will the winter of 2018-2019 be just like last year? Or will it be considerably different? And if so, how will it be different? Of course, if you have lived in East Tennessee long enough, you know that certain guides like the Old Farmer’s Almanac, persimmon seeds and even the wooly worm can be favorite destinations for predicting an upcoming winter.
One of the cycles that meteorology focuses on is the ENSO or El Nino Southern Oscillation. When the surface temperature of the Pacific Ocean becomes unusually warm off the coast of the South America around Christmas time, a prevailing global weather pattern will typically emerge. This year, however, the warming of the Pacific Ocean is more centrally located into the central part of the Pacific. We call this the El Nino Modoki, or El Nino-like. Modoki is a Japanese word which means “-like” or “in the style of”. An El Nino Modoki supports rising motion, which in turns supports an upper-level low northwest of Hawaii, and a strong ridge of high pressure over southern Alaska. If this prevailing weather pattern exists, it will allow colder air from Canada to drain down in the Eastern U.S., including East Tennessee. Therefore, it is my expectation that a cold and snowy winter is ahead of us.
From a historical point of view, the chance of a white Christmas is 10 percent or less. This year, I believe, it may be slightly higher at 15 percent.