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La Niña has returned. Here’s what that means for the Brazos Valley’s winter

Winter extremes are possible, but unlikely to be common
NOAA has issued a La Niña advisory for the upcoming winter months
NOAA has issued a La Niña advisory for the upcoming winter months(KBTX)
Published: Oct. 17, 2021 at 10:03 PM CDT
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BRYAN, Texas (KBTX) - For the second year in a row, La Niña conditions have returned for the fall and winter months. According to NOAA’s Climate Prediction Center, this is the fourth time the climate phenomenon has taken shape over the past five years -- previously starting in September 2020, November 2017, and November 2016. La Niña is not more common than El Niño. Since 1950 there have been 25 El Niño events and 24 La Niña. However, “La Niña often occurs in consecutive winters, while El Niño rarely does.” Researchers believe this has to do with the interaction between the atmosphere and the ocean during the time separating the two types of events.

The agency is calling for an 87% chance of a “moderate” event for the months of December - February. A La Niña Advisory has been issued.

What is La Niña

Simply put, when the waters over the Equatorial Pacific are cooler than average by 0.5°C or more, and it looks like that will continue for several seasons, there are strong signals a La Niña is happening or will occur. El Niño, conversely, is when the water temperatures are above average. Typically, during a La Niña event, the jet stream tends to run and remain further north across the Central and Northern United States, often bypassing the southern half of the country from big weather makers.

Typically, La Niña brings drier and warmer than average conditions to the south while cooler,...
Typically, La Niña brings drier and warmer than average conditions to the south while cooler, wetter weather is expected for the Northern US.(NOAA)

For Texas, La Niña typically means drier and warmer than average conditions than would be expected in what would be seen as a “neutral” year -- when neither climate pattern is in effect.

What does this mean for the Brazos Valley’s winter?

Simply, when we look at the outlook for December, January, and February, expect temperatures to be a bit more mild than usual and precipitation to be lacking from what is considered average. A typical Brazos Valley winter is expected to bring 10″ of rain. Drought or abnormally dry conditions ahead of the spring season could be a possibility. 2020 saw a moderate to severe drought set in during the winter months, even with the week-long winter weather event that occurred in February.

That said, extreme weather event potential is not completely off the table. Last winter was also a La Niña winter, in which the Brazos Valley saw multiple snow events and Texas was encased in a historic winter storm. Not to say that you should expect the same this upcoming winter, but notable events or sharp outbreaks of cold air are still possible in a La Niña winter, they are just less common.

For now, the Climate Prediction Center’s outlook for the Brazos Valley for December, January, February calls for a 40-50% chance of above-average temperatures and a 33%-40% chance of below-average rainfall.

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