Weak to Moderate El Nino Could Spell Stormy Winter in the East

4-30-2017
Mike Griffith, Meteorologist

ENSO ensemble plumes are pointing in the direction of an El Nino for this upcoming winter, but the question is how strong will it be. If it is weak to moderate, then the jet stream splits and the East Coat will have a stormier than usual pattern, with cold outbreaks. The key is the split in the jet stream, which allows pieces of energy to merge in the northern branch of the jet stream and the southern branch. When they combine, they create powerful east coast snowstorms. The focus of the heavy snow is mainly in the Northeast, however in the southern regions snow is still possible given how much cold air is in place before the energy arrives in the southern branch of the jet.

While it’s still early, and the computers are not always correct, a weak El Nino could prove that the pattern will be active this winter, and there could be an early start to snow and cold. Given how early the cold air arrives could be an indicator of how bad the winter will be. Not always the case, however. There could be a very cold winter but with little precipitation or dry.

But when the southern branch of the jet remains active, moisture is transported over the cold air, and the result is frequent snowstorms. There is a contradiction possibility, however.

This contradiction is if the El Nino goes moderate to strong. If that is the case, expect another warm winter in the east, with a ridge of high pressure dominating the pattern. It would be warm and wet or warm and dry if that is the case. A strong El Nino would spell little snow for the East.

However the computer ensemble plumes below point in the direction of weak to moderate as an average for this upcoming winter. That would spell cold and stormy for the East. Stay tuned!