The National Oceanic Atmospheric Administration’s winter forecast for the United States predicts that an ongoing La Niña weather pattern will bring cooler, wetter conditions in the Northwest, including in parts of Idaho.
In its U.S. Winter Outlook released Oct. 15, NOAA forecasters predict much of the northern U.S. will experience increased precipitation and colder temperatures. The report also predicts warmer, drier conditions across the southern U.S.
However, the forecast for south-central Idaho is issued with some uncertainty, with La Niña conditions bringing the region equal chances of having a colder-than-normal or warmer-than-normal winter season. The Wood River Valley is on the northern edge of an area predicted to have equal chances of a wetter-than-normal or drier-than-normal winter, and the southern edge of an area predicted to have increased precipitation, the report indicates. Areas predicted to have a higher certainty of a cold, wet winter are to the north and east of south-central Idaho.
“With La Niña well established and expected to persist through the upcoming 2020 winter season, we anticipate the typical, cooler, wetter North, and warmer, drier South, as the most likely outcome of winter weather that the U.S. will experience this year,” said Mike Halpert, deputy director of NOAA’s Climate Prediction Center.
Currently, large areas of drought extend over the western half of the U.S., with parts of the Northeast also experiencing drought and near-record-low stream flows, the NOAA report states. With the La Niña climate pattern in place, southern parts of the U.S. might experience expanded and intensifying drought during the upcoming winter months.
“The greatest chances for warmer-than-normal conditions extend across the southern tier of the U.S. from the Southwest, across the Gulf states and into the Southeast,” the report states. “More modest probabilities for warmer temperatures are forecast in the southern parts of the West Coast, and from the Mid-Atlantic into the Northeast. Above-average temperatures are also favored for Hawaii and western and northern Alaska.”
Below-normal temperatures are predicted in southern Alaska and from the northern Pacific Northwest into the Northern Plains, with equal chances for below-, near- or above-average temperatures in the remaining regions, including central Idaho.
“Wetter-than-average conditions are most likely across the northern tier of the U.S., extending from the Pacific Northwest, across the Northern Plains, Great Lakes and into the Ohio Valley, as well as Hawaii and northern Alaska,” the report states. “The greatest chances for drier-than-average conditions are predicted in the Southwest, across Texas along the Gulf Coast, and in Florida.
“More modest chances for drier conditions are forecast in southern Alaska, and from California across the Rockies, Central Plains and into the Southeast. The remainder of the U.S., including the Mid-Atlantic and Northeast, falls into the category of equal chances for below-, near-, or above-average precipitation.”
Forecasters at NOAA’s Climate Prediction Center—a division of the National Weather Service—have also been monitoring drought conditions across the nation, with more than 45 percent of the continental U.S. now experiencing drought.
Widespread, ongoing drought is currently in place across the western half of the continental U.S., primarily as a result of a weak Southwest summer monsoon season and near-record-high temperatures, the report states. Drought conditions have also developed in parts of the Northeast, Ohio Valley, Hawaii and Alaska.
“The ongoing La Niña is expected to expand and intensify drought across the southern and central Plains, eastern Gulf Coast, and in California during the months ahead,” the report states. “Drought conditions are expected to improve in the northern Rockies, Northwest, New England, Alaska and Hawaii over the coming months.”
NOAA’s seasonal outlooks do not project seasonal snowfall accumulations, as “snow forecasts are generally not predictable more than a week in advance,” the report states.
NOAA’s Climate Prediction Center updates the three-month outlook each month. The next update will be released Nov. 19.