BETHLEHEM, Pa. — If you love winter, you may be a bit bitter about the balmy outlook peddled this week by the National Oceanic and Atmospheric Administration.
As overnight temperatures Thursday dropped below 30 degrees in the Lehigh Valley, NOAA’s U.S. Winter Outlook seemed to suggest this early cold spell is not, in fact, a sign of things to come.
Or is it?
The outlook favors warmer-than-average temperatures from the southern tier of the United States to the eastern Great Lakes, eastern seaboard, New England and northern Alaska.
“Understanding our climate system is essential for making longer-term predictions like the winter seasonal outlook, which provides vital information for many of our partners and the public. We continue to innovate in this space, developing new ways to share winter forecast information with the public.”Michael Morgan, NOAA’s assistant secretary of commerce for observation and prediction
Probabilities of above-average temperatures are strongest along the Gust Coast and most of Texas, with a 40-50% chance of above-normal temperatures in much of the mid-Atlantic.
The outlook comes after a $100 million investment into a high-performance computer system that NOAA says will advance research on weather, climate and ocean predictions.
“Understanding our climate system is essential for making longer-term predictions like the winter seasonal outlook, which provides vital information for many of our partners and the public,” said Michael Morgan, NOAA’s assistant secretary of commerce for observation and prediction.
“We continue to innovate in this space, developing new ways to share winter forecast information with the public.”
Will La Niña be a factor?
Experts say a slowly developing La Niña will influence conditions for the upcoming winter across most of the country, with the outlook covering December 2024 through February 2025.
The Southeast and mid-Atlantic tend to see higher-than-average temperatures during a La Niña winter.
But what about precipitation?
La Niña conditions typically lead to a more northerly storm track during the winter months. As a result, NOAA forecasters, in collaboration with the National Integrated Drought Information System, orNIDIS, expect drought conditions to persist and worsen across the central and southern Plains of the United States.
The Lehigh Valley, which now is in drought status, has equal chances for above- or below-average precipitation.
“Unfortunately, after a brief period in the spring of 2024 with minimal drought conditions across the country, more than a quarter of the land mass in the continental U.S. is currently in at least a moderate drought,” said Brad Pugh, operational drought lead with NOAA’s Climate Prediction Center.
“And the winter precipitation outlook does not bode well for widespread relief.”
‘Not as cut-and-dry as it seems’
Local meteorologist Bobby Martrich typically avoids seasonal outlooks for a reason.
“It’s literally flip a coin,” Martrich said Friday, describing long-range outlooks as “especially difficult this year” because of uncertainties with what could be a weak La Niña and when or if that transition occurs.
“The warm pool in the Western Pacific is farther east than the typical La Niña,” Martrich said, emphasizing it could retract and “become more La Niña-like” or build farther east.
“While the milder outlooks that are out there have merit and support, it’s not as cut and dry as it seems and there can be some surprises, especially earlier in winter."Local meteorologist Bobby Martrich
That would have “huge downstream implications on our winter,” he said.
“While the milder outlooks that are out there have merit and support, it’s not as cut-and-dry as it seems and there can be some surprises, especially earlier in winter," he said.
That's because of tropical forcing in the Western Pacific favoring colder phases earlier in the winter in a weak La Niña, but they are "torch phases later in winter," he said.
He described latent heat release from storms that guides the jet stream ridges and troughs downstream.
Without going "way over people's heads," he said, it's important to remember that winter is never that predictable.
"If you remember the 2015-16 winter, it was looking ugly at best," he said. 'Everyone predicted a torch [warm] winter for the entire season.
"It was rather warm for most of it, but we also had a 32-inch snowstorm in the middle of that. The biggest of all time in fact, for ABE [Allentown/Bethlehem/Easton]."
AccuWeather’s winter outlook suggests December could bring brief blasts of cold air, but January’s pattern could promote milder air and less snow across the eastern half of the country.
