CHICAGO (CBS) — The forecast for this year’s winter is another wildcard due to a possibility of a second La Nina.
Forecasters at NOAA’s Climate Prediction Center released Thursday the U.S. Winter Outlook and the weather lies in the hands of a possible La Nina.
“If La Nina conditions develop, we predict it will be weak and potentially short-lived, but it could still shape the character of the upcoming winter,” said Mike Halpert, deputy director of NOAA’s Climate Prediction Center, in a statement. “Typical La Nina patterns during winter include above average precipitation and colder than average temperatures along the Northern Tier of the U.S. and below normal precipitation and drier conditions across the South.”
As for the Chicago outlook…
With the possible 55-65 percent chance of La Nina developing before winter, NOAA forecasters predict a wetter winter (December through February) for the Great Lakes region – about 40 percent wetter. The temperature prediction falls into the “equal chance” category, which means “they have an equal chance for above-, near-, or below-normal temperatures and/or precipitation because there is not a strong enough climate signal in these areas to shift the odds,” NOAA said.
And for the rest of the U.S., most of the northern region can expect wetter-than-average conditions and the entire southern region will see drier-than-normal conditions.
The Northern Tier of the country, from Minnesota to the Pacific Northwest and in southeastern Alaska, are predicted to have below-average temperatures, while the southern two-thirds of the county, the East Coast, Hawaii and western and northern Alaska are predicted to have warmer-than-normal temperatures. The rest of the country, including Chicago, falls into the “equal chance” category, which means they have an equal chance for above-, near-, or below-normal temperatures.
And while the prediction believes precipitation will be above-average this winter, there is still a chance of drought conditions in parts of the northern Plains. Improvement is anticipated farther West, NOAA said, but a drought could develop throughout the South in regions that missed rainfall during hurricane season.
But La Nina is not the only factor that can influence this year’s winter weather. Other factors include the Arctic Oscillation, “which influences the number of arctic air masses that penetrate into the South and is difficult to predict more than one to two weeks in advance,” and the Madden-Julian Oscillation, which can cause heavy rain along the West Coast, according to NOAA.
What about snow?
NOAA’s winter outlook does not predict snowfall accumulations because “snow forecasts are generally not predictable more than a week in advance, because they depend upon the strength and track of winter storms.”
The last two years, winter saw above-average temperatures throughout the country, but some parts were still hit with major snowstorms.
NOAA will be updating their U.S. Winter Outlook on Nov. 16.