This is a daunting prospect for areas already stressed by prolonged drought and could increase wildfire risk in parts of the south-central United States that do not normally face such dangers. Prolonged and exacerbating dry conditions are likely in the Southwest as well as in states like Kansas and Oklahoma, which are experiencing extreme and in many cases exceptional drought, according to the US Drought Monitor.
That could mean lingering worries about the Mississippi River, where low water levels are making it difficult to transport goods via barges. Climate forecasters predict developing drought in the lower Mississippi Valley and seasonally dry conditions in the Missouri River Basin, although drought conditions may ease along the Ohio River.
And that means no slowing down in the momentum of a mega-drought in California and the West, without relief for the parched Colorado River basin and dangerously depleted southwestern reservoirs like Lake Mead and Lake Powell.
“Part of the reason for the persistence [drought] The forecast is La Niña, but also the long-term nature of the drought,” said Brad Pugh, meteorologist at NOAA’s Climate Prediction Center.
According to the latest weekly Drought Monitor report, more than 80% of the continental United States is experiencing at least abnormally dry conditions, or even drought, the highest proportion since reporting began in 2000.
“Drought conditions are now present in approximately 59% of the country, but parts of the western United States and southern Great Plains will continue to be the hardest hit this winter,” said Jon Gottschalck, Chief from the climate center’s operational forecasting branch, in a statement. statement. “With the La Niña weather pattern still in place, drought conditions may extend to the Gulf Coast as well.”
On the other hand, winter precipitation is expected to be even heavier than normal in the Pacific Northwest, and storm systems could also produce above normal precipitation in the Great Lakes region, according to forecasts.
Relatively mild and dry conditions are also expected to extend along the Interstate 95 corridor on the East Coast, meaning cities from Washington to Boston are likely to be near the line between rain and falls. snowfall for any storm moving up the coast, Gottschalck said. .
Seasonal forecasting can be a challenge for meteorologists because the main weather forecasting models they use are designed for relatively short-term forecasts. Forecast accuracy breaks down more than a week in advance, so for forecasts like the ones NOAA released on Thursday, scientists rely largely on signals from global climate models like La Niña.
Some years, seasonal forecasts may be worse than a random guess.
In the United States, La Niña is known to create hot and dry conditions in the southern part of the country, with cooler and wetter than normal conditions along its northern part, including the Pacific Northwest. and the Midwest. That’s because it tends to move the jet stream — a band of atmospheric winds that directs weather systems across the continent — toward northern states and Canada.
Despite the influence of La Niña, Gottschalck said there is significant uncertainty in weather patterns for much of the central part of the country, where forecasters predict equal chances of cold or mild conditions and dry or wet conditions. La Niña can allow for considerable “week-to-week variability,” as shown by the extreme cold that spread across the country and caused an energy crisis in Texas in February 2021, he said.
In the winter of 2020-2021, the current La Niña streak had just begun, yet the season was marked by historic cold across the contiguous United States. The polar vortex, a column of freezing air that remains generally contained over the North Pole region, has spread south and produced some of the snowiest winters on record in the Deep South.
Still, NOAA’s forecast for this winter closely matches the charts used to describe classic La Niña conditions. Gottschalck said that while NOAA uses long-range forecast models to guide its predictions, typical La Niña expectations “serve as a first guess.”
La Niña impacts around the world include dry conditions in Peru, Chile and the Horn of Africa, and heavy rains over Southeast Asia and Australia. The United States Climate Prediction Center expects a 75% chance that La Niña will continue through at least winter.
This year, NOAA’s forecast is in line with other conventional ideas, including seasonal forecasts published by AccuWeather and Weather Channel that call for a continued La Niña influence on weather patterns.
