All indications are that the current La Nina phase in the Equatorial Pacific Ocean is maintaining itself.
During the past month sea-surface temperatures have cooled a little more across the central and eastern Pacific. This suggests that the La Nina may be strengthening slightly. The latest suite of climate model runs continue to project that this La Nina episode will persist through at least the winter and as a result will influence temperatures across the country.
Slightly cooler than average January temperatures are forecast for portions of the north-central Plains, upper Midwest, as well as parts of Oregon, Nevada and northern California. A surplus of total heating degree-days of between 30 and 90 is expected throughout these regions. Heating costs also likely will be somewhat higher than average.
In contrast, much of the southern Plains, lower Mississippi Valley and Deep South are projected to see temperatures average slightly warmer than normal. Heating degree-day deficits of between 30 and 60 will be common across these areas.
The Northeast, Mid-Atlantic and Ohio Valley are expected to see January temperatures average closer to normal. If the North Atlantic Oscillation becomes more negative, however, temperatures colder than forecasted are possible.