After a late-December respite from the bitter chill in the central and eastern United States, colder temperatures are likely to return for the beginning of the new year and intensify by February, according to the latest outlook from The Weather Company, an IBM Business.
Temperatures are expected to be below average overall from the South to the mid-Atlantic from January through March 2019. Temperatures are forecast to be near-average or slightly colder from the Southwest to the central Plains, Midwest and Northeast.
Any above-average temperatures will likely be confined to the West and Northwest during the first three months of the new year. Above-average warmth, by winter standards, is expected from Northern California to parts of the northern Plains, with temperatures even farther above average forecast in the Pacific Northwest.
“The current magnitude/flavor of El Niño event and expected high-latitude blocking associated with the solar minimum (and backed up by the November blocking) add up to heavily skewed odds toward a colder, stormier late-winter period,” said Dr. Todd Crawford, chief meteorologist with The Weather Company.
Below, we’ll dive deeper into the month-by-month details to help you plan for the remainder of winter.
Temperatures are forecast to trend colder in January across the eastern and southern U.S.
Below-average temperatures will likely be found in much of the South, from southern New Mexico eastward to South Carolina. Near-average or slightly colder temperatures are expected from the Desert Southwest to the Midwest and East.
“The stratospheric polar vortex has been taking a beating, and there are indications that a significant stratospheric warming event is coming soon, by displacement or split, which may also help to increase probabilities of the sort of high-latitude blocking that would favor a colder late-winter look,” Crawford said.
The polar vortex is a whirling cone of low pressure a few miles above the poles that’s strongest in the winter months due to the increased temperature contrast between the polar regions and the mid-latitudes, such as the U.S. and Europe. We discussed how a displaced or split polar vortex could unleash a much colder January in this article from Dec. 18.
Temperatures are forecast to be above average from Northern California to northwestern Minnesota in January, while much-above-average warmth will likely be found from the Pacific Northwest to northwestern North Dakota.
A swath of near-average or slightly warmer temperatures is expected from Southern California to the central Rockies, central Plains and upper Mississippi Valley.
The last full month of winter is expected to be the harshest in terms of unusually cold weather for a large swath of the Midwest and East.
Far-below-average temperatures are likely in those regions, with below-average temperatures also reaching into much of the Plains, Mississippi Valley and South. February is normally the coldest month of the year in many of these areas, but the outlook calls for even colder weather than usual.
“Everything is still on track for a notably cold, stormy late-winter period in the eastern and southern U.S., especially in February,” Crawford said.
Meanwhile, mild conditions are expected to persist in the West. Above-average temperatures are forecast from Northern California to the northern Rockies, with the core of the warmth once again situated over the Pacific Northwest.
Temperatures are likely to be near-average or slightly warmer from Southern California and the Desert Southwest into parts of the Rockies.
“Climate models have been unusually stable and in good agreement in depicting the colder look for the eastern and southern U.S. for the remainder of winter and into early spring,” Crawford said.
The first month of meteorological spring – which runs from March through May – is expected to be a bit milder in the upper Midwest, Great Lakes and Northeast after a frigid February, with near-average or slightly warmer temperatures in the forecast.
However, temperatures are expected to be near-average or slightly colder from the lower Midwest into much of the South and Southwest. Parts of Texas will likely experience the coldest temperatures relative to March averages.
Above-average temperatures are once again expected in the Northwest, and the warmth could extend into parts of the upper Mississippi Valley as well. Temperatures are forecast to be near-average or slightly warmer from Central California to the central Plains.
“It currently appears as if the El Niño event will not decay significantly heading into spring, which should favor the continuation of cooler-than-normal temperatures across much of the southern and eastern U.S. into at least May,” Crawford said.
Editor’s Note: This story was written by The Weather Company.