Indications are that this winter we will still be having a LA NINA in the Pacific Ocean (cooler than normal sea-surface temps in key regions).
And if so that would make it a rare third La Nina Winter in a row in history. According to the National Centers for Environmental Prediction, La Niñas occurred several times between 1903 to 2010 and 2010 to 2012.
Some recent ones using better data since 1950 (depending on agency definition) are 1954-57, 1973–1976 and 1998–2001.
We know from history what THE AVERAGE La Nina winter looks like for precip and temperatures over the 3 winter months in the mean. But no two are ever exactly alike. And other factors in oceans, atmosphere, cryosphere, and stratosphere do influence the winter weather over time.
But since the Pacific Ocean is such a big weather pattern driver let’s look at it in isolation for a “first guess” at the coming winter.
MODERN ERA LA NINA COMPOSITE TEMPS AND PRECIPITATION SINCE 2000 NOVEMBER-MARCH:
PACIFIC OCEAN ENSO CONDITION FOR COLDEST AND SNOWIEST:
So all things being equal the La Nina is an indicator for a milder than average winter and a drier than average winter, with snowfall normal to below-normal.
HOWEVER, you can not broad brush every La Nina as guaranteed to be the same as all others. They produce different outcomes based on the TOTAL global picture including the progression and type of La Nina. There have been rough winters in the East such as 1995-96 that would have been projected warm because of La Nina. There are different flavors of La Nina determined on both how cold the waters are and where the coldest is located. That can change things, and as I mentioned at the start of this blog, there are also other important pattern drivers that influence the winter average when they moderate the La Nina impact.
We will know more about the indicated “flavor” of this La Nina later in November when we have more data and trends to look at in the Pacific and in the other oceans as well. The forecast probability and strength of La Nina could change this month and next.
I am NOT YET convinced that this will be more than a weak La Nina.
In fact many models show NEUTRAL CONDITIONS developing from January to March 2023.
So I will make my own winter outlook in the future.
For more frequent updates follow me on Twitter @MellishMeterWSB.
If it turns out to be a WEAK La Nina they tend to be less dry and less warm than moderate or strong ones.