YORK, Pa. — It's that time of year again, that the same question keeps coming up. How much snow are we going to get this year?
And, listen, the National Oceanic and Atmospheric Administration's Climate Prediction Center DID just release their winter weather outlook. But, even as we're knock, knock, knocking on Winter's door (see what I did there?), this is essentially an educated guess. Maybe better odds than flipping a coin, as individual weather patterns are simply slightly more likely based on the overall picture right now.
However, I yield to the crowd of voices wanting to know.
As mentioned, NOAA's CPC (holy acronym, Batman) released their winter weather 2021-22 outlook, which features much of the country expecting warmer than normal temperatures under the influence of La Nina conditions in the Pacific Ocean.
The temperature outlook in South Central PA is similar to that of the southern and eastern United States, and calls for a 40-50 percent chance of seeing above normal temperatures across the months of December, January, and February. The only part of the country that is expecting cooler than normal temperatures this winter is the Pacific Northwest into the northern Rockies.
In regards to precipitation, the southern half of the country is forecast to have below normal precipitation, while here in South Central PA, the forecast places us having near normal to slightly above normal precipitation.
This forecast is fairly similar to last year’s winter forecast from the CPC, as Chief of the Operational Prediction Branch Jon Gottschalck explains.
“The second winter in a row, La Nina conditions have developed and are forecast to continue into spring 2022. Therefore, the temperature and precipitation outlooks are somewhat similar to the forecasts issued last year.”
La Nina occurs when there is cooler than normal sea-surface temperatures in the eastern tropical Pacific Ocean. This cooler water can change tropical rainfall patterns and, as a result, change the jet stream pattern across the Pacific and North America. These changes in the jet stream then result in patterns that meteorologists have seen over the years.
While the forecast calls for a warmer and wetter winter season in PA, that does not mean we will not get cold snaps or dry periods. The forecast is simply an average over the three months of meteorological winter.
Gottschalck also reminders folks that these long range forecasts are not a guarantee. “The nature of a probabilistic forecast means that other outcomes are always possible, just less likely.”
Until next time,
-Chief Meteorologist Bradon Long and Meteorologist Danielle Miller