La Nina likely to affect our winter averages

Published 10:46 am Saturday, October 23, 2021

By Skip Rigney

The winter of 2021-2022 will likely be milder-than-normal in much of the southeastern United States according to an outlook issued by the National Oceanic and Atmospheric Administration (NOAA) on Thursday.

The NOAA Climate Prediction Center’s (CPC) seasonal outlook applies to the average temperature for December, January, and February. Of course, like every winter, we will certainly have some cold snaps. However, CPC estimates that once all the temperature data are collected at the end of February 2022, average temperatures for the previous three-month period will probably be warmer than the historical averages across much of the southern half of the United States, as well as the Northeast. The highest chances for above-normal winter temperatures is in a band extending about 150 miles inland from the Gulf Coast and into Georgia and the Carolinas.

If the scientists at CPC are right, we can expect lower electric bills than in most winters. However, not all the consequences of a mild winter fall on the positive side of the ledger. For example, will blueberry bushes get enough “chill hours” to produce good fruit yields next spring? Will there be enough freezes to knock down some of our always abundant insect populations?

CPC is not as confident about precipitation, but their winter outlook leans towards drier-than-normal rainfall accumulations across the Gulf South for the three-month period. That might be a welcome change given the extremely wet 2021 that we have had.

CPC’s outlook is heavily based on the recent re-emergence of an oceanic and atmospheric pattern known as La Nina. La Nina was ongoing from the summer and fall of 2020 through last winter, but it faded away for the spring and summer of 2021.  La Nina’s definitive signature is cooler-than-normal sea surface and upper ocean waters in the tropical eastern and central Pacific Ocean. The ripple effects, especially in atmospheric patterns, reach far beyond the Pacific. The jet stream can become quite erratic over the northwest Pacific and central North America, while the southern United States typically sees less rain and milder overall temperatures during La Nina winters than in other winter seasons.

But, before we get to winter, we still have more than a month of autumn on the calendar. However, CPC’s outlook for November shares the same general characteristics as their winter outlook with the odds leaning toward a drier and milder-than-average November in our area.

The next few October days will definitely fall on the warm side of the historical averages as we wait for the arrival of the next cool front. Highs are forecast to be in the 80s with early morning lows in the 60s through Tuesday. That is well above the historical average daily temperature range during the last week of October in Pearl River County, which is from around 50 degrees for a low up to the middle to upper 70s for highs.

Temperatures will drop close to that climatologically normal range for the latter half of the upcoming week after a cool front passes. Ahead of that cool front there will be rain and possibly some strong thunderstorms.  It’s still too early to nail down the exact timing, but the severe weather potential will likely be highest sometime Tuesday night, Wednesday, or Wednesday night.