#NEWS CENTER 22 UPDATE#

There is some tendency for above-average temperatures across the southern U.S. La Niña’s influence is generally less consistent for winter temperature than for precipitation across the United States. Maps by NOAA, based on NCEI climate division data provided by the Physical Sciences Division at NOAA ESRL. The strongest La Niña episode is on the top left, and the weakest of the 20 episodes is on the bottom right. Dark green colors indicate much wetter-than-normal conditions, and dark brown colors indicate much drier-than-normal conditions. The December-February ONI for each episode is shown in parentheses (units of ☌) above each map. The strength is measured by the December-February Oceanic Niño Index (ONI), which is three-month average surface temperature departure from normal in the Niño 3.4 region. Winter precipitation patterns during each of the 20 strongest La Niña episodes since 1950. Of course, the reliability of the La Niña influence is far less than 100%, with the dry signal occurring about 70-80% of the time in the Southeast and the other signals even less reliable. Also, those La Niñas were linked to wetter-than-average conditions in the Great Lakes/Ohio Valley region, the Pacific Northwest, and the northern tier of the U.S., although there is less consistency to these impacts. For instance, as I discussed in last year’s post, most of the 20 strongest La Niña events of the past 70 years brought drier-than-average conditions across much of the southern tier of the U. In fact, much of the historical skill for seasonal precipitation forecasts stems from the occurrence of La Niña or El Niño. This influence results in enhanced predictability, as the patterns of both temperature and precipitation during most episodes share many features. What I’m about to write shouldn’t surprise long-time blog readers, but the occurrence of La Niña (as well as El Niño) often exerts a significant influence on winter climate over North America.

#NEWS CENTER 22 UPDATE#

Will we see a typical response to La Niña this year (sure didn’t see it last year) or will other factors play a more significant role than La Niña again this year? Are La Niña impacts more reliable in the second year of a “double-dip” event? Finally, how will the update to the long-term temperature and precipitation averages affect the outlooks? So many questions, so little time (Aunt Edna is in for a treat), so let’s get started! Sitting at the head of the table weather and climate during the upcoming winter.

If you’re still searching for something to talk about with Aunt Edna at the Thanksgiving dinner table, I have some good news for you – it’s time for my annual NOAA Winter Outlook post! ( footnote #1) If this post gives you a feeling of déjà vu, I can understand why for the second year in a row, La Niña has developed and is expected to impact the U.S.

We will miss having his steady hand at the ENSO blog and wish him the best! Mike is famous to us because he played a critical role in discovering and documenting climate impacts associated with El Niño and La Niña in a set of very highly cited papers that won awards. He has patiently answered oodles and oodles of questions about climate outlooks, starred in many of 's video outlooks, served on the science advisory panel, and acted as a moderator moderator on the blog since inception in 2014. He has worked at NOAA Climate Prediction Center for 41 years and has served as Deputy Director for the last 15 years. Mike Halpert has guest blogged for us each fall, and because this is his last guest blog before retirement in later 2022, we want to briefly highlight his contributions.

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