For the first time in several months, the current La Nina phase in the Equatorial Pacific Ocean has shown some signs of weakening. Sea-surface temperatures across portions of the eastern Pacific Ocean off of South America have warmed several degrees during February and are running slightly warmer than average.
This trend must be monitored closely to see if further weakening takes place across more of the Equatorial Pacific. Some climate models predicate this La Nina will weaken into a neutral phase by May or June. Other models keep a weaker La Nina in place. What happens in the next couple of months to this La Nina could have a significant impact on temperatures across North America during summer.
As far as April goes, slightly warmer than average temperatures are expected throughout the western Gulf Coast, southern Plains and Desert Southwest. These portions of the country likely will see a surplus in early season cooling degree-days by between 30 and 90. Parts of the Tennessee Valley, Southeast and Ohio Valley also are forecasted to see mild April conditions. Late season heating degree-days will be lower by between 30 and 60 as a result. Climate indices continue to suggest slightly cooler than average temperatures across the Pacific Northwest and northern Rockies during this time, which will lead to higher late season heating costs.