Although there can be a good deal of variability during winter seasons featuring El Niño conditions, there are usually some underlying patterns that tend to be repeated on a frequent basis. First off, El Niño winters tend to feature an unusually strong area of low pressure across the Gulf of Alaska / Northern Pacific Ocean. This has two main impacts. The first is to result in an enhanced subtropical jet stream across the southern part of the nation – which typically leads to cooler and wetter than normal conditions. The second impact is an expansive area of warmer weather across the northern-tier of the nation – including the Midwest, Mid-Atlantic and Northeast. Also because of a more zonal flow (less amplified) pattern, conditions also tend to be on the drier side of normal, with less frequent snowstorms and strong weather systems. This is especially true across the Midwest, as the region is well removed from the main storm track (see the top part of the schematic below).
Nearly opposite conditions exist during La Niña winters, with an unusually strong area of high pressure setting up across the Northern Pacific Ocean. This usually translates to a more amplified pattern featuring a ridge across the Intermountain West and a trough of low pressure across the Midwest and Northeast. As a result, colder Canadian air typically works its way down into these regions, setting the stage for more cold weather outbreaks than in El Niño years. In addition, winters featuring a La Niña are more likely to have stronger East Coast snowstorms, with a generally more active weather pattern across the eastern third of the nation. Conversely, areas across the southern-tier of the nation usually see warmer and drier conditions when compared to average (refer to bottom part of the image above). That being said, if you are a snow lover that lives in the Northeast or Midwest, you should definitely be rooting for a La Niña as opposed to an El Niño.
