During the past couple of months, sea-surface temperatures across much of the equatorial Pacific Ocean have remained warmer than average by between 1 and 2 degrees Celsius. As a result, the El Nino phase continues to persist and current long-range climate models suggest that it will remain through at least spring.
Despite the ongoing El Nino, portions of the Midwest and Northeast saw a cooler than normal winter, which is a rare occurrence during an El Nino event. The North Atlantic Oscillation (NAO), however, has been negative almost the entire winter, and, as a result, an upper-level weather pattern that is conducive for keeping colder air masses in place became established across the eastern third of the country.
Looking toward March and April, the latest forecast models suggest that the NAO will remain negative throughout most of March, but might begin to swing more positive in April. Temperatures are forecasted to end up averaging close to normal across much of the Midwest and Great Lakes with portions of the Northeast seeing slightly cooler than normal conditions during the next couple of months. Locations from the southern plains to the Southeast are also likely to see a cooler than normal early spring, which is typical during El Nino. Late-season heating degree-days are expected to be at a surplus of between 60 and 120 across these parts of the country.
On the flip side, portions of the northern Rockies and Pacific Northwest are forecasted to experience slightly warmer than normal temperatures, which will lead to lower energy costs with respect to heating during March and April.