What Does the Return of El Niño Mean for Colorado? — Matt Makens #COdrought #COwx

Jet Stream patterns El Nińo /La Nińa via NWS Boulder
Jet Stream patterns El Nińo/La Nińa via NWS Boulder

Here’s a primer of sorts about El Nińo and the possible effect on Colorado weather from Matt Makens writing for Weather5280.com. Click through and read the whole post and check out the great graphics. Here’s an excerpt:

The fact is, where we live, an El Niño or La Niña pattern doesn’t change our temperatures or moisture outlook. It may shift where heavier precipitation will fall, but it doesn’t do much for the state as a whole. There are seasonal changes for some regions that can be of benefit/detriment, but the scale of a year and only looking at the state yields little excitement.

In general terms, the ENSO (El Niño Southern Oscillation) is yet another ocean-atmosphere connection that affects the storm track and speed over Colorado. During La Niña (as in this winter) heavier snows hit the northwestern mountains and more frequent cold snaps occur for the plains with periods of strong wind. However, in El Niño the heavier snowfall shifts to the southwestern mountains and the temperatures remain a bit warmer…

Notice how there isn’t a correlation between ENSO and Colorado’s temperatures and precipitation? I did a quick analysis for Denver and there are not any correlation there either. Just because the headlines tout a change on the way and you may want to throw an El Niño welcome party, there’s little to get worked up about here in Colorado from the state’s perspective. Okay, yes if you are in the southwestern mountains and wanting a good winter snowfall you want El Niño, but don’t get your hopes up too soon, the El Niño indicator is a weak one and may not hold on for next winter…

We are in a long lasting drought (most severe over the southeast), and what the entire state needs right now is moisture. Aside from the singular flooding event for northern Colorado back in September, we too would still be in a drought. The state’s agricultural community needs a multi-decadal pattern switch that simply the ENSO pattern itself can’t fix. However, a quick transition from La Niña to El Niño this spring and early summer would be nice…in that change, climatologically the southeastern plains have the best chance for above normal precipitation. However, a bigger pattern change with El Niñ0 and other factors coming together is what it will take to make major state climate changes.

There are so many more important influencing factors from other patterns, like MJO, AMO, and PDO that do have a direct correlation to our hotter/drier versus cooler/wetter patterns.

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