ALBUQUERQUE, N.M. — I feel a little like a cheap carnival barker foretelling you this, but FYI, it looks like El Niño is coming.
New Mexico water managers, grappling with their fourth straight year of drought, have a tired look in their eyes. Mention El Niño and you’ll see a spark of life. That is because the Pacific climate pattern with the lyrical name is associated with wetter weather.
Step right up folks, come see the Amazing El Niño, bringer of moisture to the parched state of New Mexico! You’ll thrill to its crashing thunderstorms, its snowpacked mountains and brimming rivers!
But you saw what I did there, right? “Is associated with wetter weather.” Already with the weasel words. The carnival barker in me is excited, but the cautious journalist in me has been talking with cautious scientists. El Niño comes with no guarantees.
Since mid-February, forecasters have been watching an expanding pool of warm water in the eastern Pacific, growing more confident that El Niño is on the way. When it arrives, its big, warm pool of ocean water changes weather patterns across North America for as much as a year. Generally, it makes New Mexico wetter. But the devil is in the details.
Last Thursday’s monthly forecast by the federal government’s Climate Prediction Center was the agency’s most confident yet, with a 65 percent chance that we’ll get an El Niño by summer and a nearly 80 percent chance that it will show up by autumn.
New Mexico water managers need some good news. Last year, the Rio Grande was close to dry by the end of June before a good burst of monsoon rains in early July bailed us out. This year, with reservoirs further depleted and our fourth consecutive abysmal winter snowpack, the water scramble is again underway as managers try to stretch their supplies, hoping for summer rains.
“It’s going to be another very tight year,” said Mike Hamman, head of the Bureau of Reclamation’s Albuquerque office.
Could El Niño tip the odds of good summer rains in Hamman’s direction?
In 1997, as the last big El Niño was getting underway in a pattern very similar to what’s going on today, the summer rains in Albuquerque started in June and the weather was consistently wet through September. But in 1982, another similar year, summer rains were a mixed bag across the state, according to Andrew Church, a forecaster at the National Weather Service’s Albuquerque office who has been following El Niño’s development.
The last El Niño began in the summer of 2009, and it was a wet monsoon season across most of New Mexico, according to Church.
In general, in years when El Niño looks like the current one, New Mexico’s summer rains tended to be above average, according to Klaus Wolter of the federal government’s Earth Systems Research Laboratory in Boulder, Colo. But not always. In 1984, it looked like El Niño was getting cranked up in the spring, only to fizzle by summer. New Mexico had below-average summer rains that year.
Church thinks that, in addition to a brewing El Níño, there’s a second factor working in favor of a good summer rainy season. In an interview last week, he pointed on his maps to unusually warm water along the coast of North America. When those two features combine – warm water along the equator and warm water along the coast – they tend to give summer rains here a boost, Church said.
Other research, however, notably the work of atmospheric scientist Chris Castro at the University of Arizona, argues that El Niño may have the opposite effect, drying out the Southwest’s summer rainy season. The difference between Castro’s findings and Church’s analysis may simply involve geography: The area Castro studied is more Arizona-centric. Church’s maps show that monsoon rains during El Niño years favor New Mexico over Arizona. So there’s an argument here that we may end up the beneficiaries at the expense of our neighbors to the west.
The bottom line in all of this is that the impact of El Niño on our summer rains is murky. “There’s more that we don’t know, than we know,” said Mike Crimmins, a climate researcher at the University of Arizona.
By the fall and winter, the impact of El Niño is more clear. A strong El Niño significantly increases the odds of a wet winter, meaning a big snowpack for 2014-15 and better chances of good river runoff. According to an analysis by Kelly Redmond at the Western Regional Climate Center in Reno, Nev., strong El Niños are not a guarantee of good fall and winter precipitation. Sometimes they are just average. But, importantly for water managers like Hamman, El Niño years are almost never dry, according to Redmond’s analysis.
For the coming year, that may be El Niño’s most important gift – a steep reduction in the odds of a fifth consecutive year of extreme drought. But be cautious. Remember when I tell you all this that I’m just a cheap carnival barker.