Saturday, May 09, 2020

We're Officially in a Weak El Nino

That is, according to the Oceanic Niño Index (ONI), the 3-month running mean of ERSST.v5 SST anomalies in the Niño 3.4 region (5°N-5°S, 120°W-170°W)].

5 consecutive months of ONI ≥ 0.5 is considered to be an El Nino. The last five months have barely slipped under that line:

It's not quite as strong as last winter's El Nino, but it does help explain why this winter's temperatures are or are bordering on new highs. (But not why they're on par with, or exceeding, the winter of 2015-2016's El Nino.)

And if this was a significant El Nino, we wouldn't be seeing record breaking ocean heat content.


Layzej said...

We had a straight up blizzard in Southern Ontario yesterday :(

Records fell like dominoes as the icy air mass spilled south, first lapping at the Midwest before surging all the way east to the Atlantic. It’s one of the most prolific late-season cold outbreaks on record, thanks to a piece of the low-altitude polar vortex breaking off and meandering uncharacteristically far south.

David Appell said...

Yeah, I read about that cold and snowy outbreak back east.

Here is the Pac NW we had the best weather so far this year -- dry & highs in the 80s. I guess it was the jet stream going down for you and up for us.