Rejoice skiers! La Niña now forecast to make a reappearance this winter
Surprise!!! La Niña may be back this winter.
NOAA's Climate Prediction Center issued a "La Niña Watch" Thursday, which means there is now a high probability La Niña conditions will develop within the next six months- namely this fall and winter.
If true, it'll be a second La Niña episode in a row.
A Double La Niña? WHAT DOES IT MEAN?!?
La Niña winters tend to be a bit cooler and wetter than usual with an average-to-above average mountain snowpack. (Skiers and snowboarders: "Woo-hoo!" WSDOT snow plow drivers: "Ugh..."). That also goes for the lowlands -- a better chance of lowland snow events are in La Niña winters. (Kids: "Woo-hoo!" Kids at heart: "Woo-hoo!" Commuters: "Ugh..." California transplants: "Dear God, NO!" Alaska transplants: "Whatever...")
For windstorms, La Niñas tend to feature an increased number in general, but the really big windstorms that get fancy names like "Inauguration Day Storm" tend to happen in neutral years. As for flooding events, about average in number.
For those that crave a reference, last winter was a weak La Niña episode which featured Seattle's first lowland snow events in a few years and one of the cooler December-Januarys in a while.
But while we typically go from El Niño to neutral to La Niña, getting two La Niña's in a row -- sometimes called a "Double Dip" La Niña -- is not unheard of, especially after a strong El Niño phase. Remember in 2014-15 we had a record-ish El Niño, followed by a weak La Nina last year. Looks like we're going for Part II. Double Dips have also happened in 1974-75 and 2011-12.
Wait, Wasn't it supposed to be an El Niño or neutral winter?
Yes. Odds of another La Niña forming were considered a long shot earlier this year, when forecasters originally gave El Niño a 60-66 percent and then gradually became more set on a neutral fall and winter.
But then again, it's extremely difficult to get a forecast beyond spring due to the "Spring Predictability Barrier" -- then the atmosphere tends to wash out of any El Niño/La Niña phase and it's more difficult to get good data on where it atmosphere is leaning.
Now that we're closer to autumn (like, a week away) forecasters say that while overall, a number of climate models suggest we'll remain in neutral conditions (neither La Niña or El Niño), the latest models are trending more toward La Niña. And the forecasts run in September have a very good track record of being correct, says the folks at NOAA's Climate.gov.
What's more convincing: climatologists are already seeing cooling at deeper parts of the Central Pacific Ocean leading them to believe the more recent models are on the right track.
To that effect, forecasters now give La Nina a 55 percent chance of reaching La Niña conditions in early autumn, and a 61-62 percent chance of La Niña conditions into the early winter months. Remaining in the neutral phase is around 35 percent, with now just a fractional chance of reverting to El Niño.
The official winter forecasts come out in October but we'll get a hint at what they might be leaning with this new La Niña data when the Climate Prediction Center gives their October-December forecasts next Thursday.
Don't be surprised to see it trending now toward a cooler and wetter fall and winter once again.