Sea-surface temperatures across much of the equatorial Pacific Ocean are running about average. As a result, the ENSO phase has remained neutral during the past month. Latest climate models indicate that phase may persist well into the upcoming summer months. In the past couple of weeks, however, warming has developed across parts of the eastern Pacific Ocean. This will have to be monitored for signs of an overall warming trend, a possible El Nino development.
As for May, warmer than average temperatures are expected across parts the Desert Southwest and much of Texas, where drought conditions continue to develop gradually. These areas are projected to see an early season cooling degree-day surplus of between 30 and 90 and slightly higher than normal energy costs with respect to cooling. There indicate that portions of the Northeast, Mid-Atlantic, Ohio Valley and Tennessee Valley might see slightly above normal temperatures. Across these regions, NAO (North Atlantic Oscillation) might become positive in May after a long negative period the past couple of months. If this occurs, it could help set up a warmer weather pattern across the eastern third of the country. Parts of the northern Rockies are forecast to see slightly cooler than normal temperatures, which will likely result in a slight late-season surplus of heating degree-days.