Monsoon forecast isn't rosy, but it's better than last year
NWS forecaster holds out hope for good precipitation
FARMINGTON — Anyone hoping for a whopper of a monsoon season this summer in the Southwest after last year's flop likely won't be thrilled by this year's forecast. But, comparatively speaking, it's still pretty good news.
"It is definitely a better outlook than last year," meteorologist Andrew Church of the National Weather Service in Albuquerque said shortly after posting the "2020 Monsoon Outlook for Central and Northern New Mexico" on the agency's website on the afternoon of June 15. "It was one of the hottest and driest on record."
This year's outlook calls for near-average to slightly below-average precipitation for the Southwest and slightly above-average to above-average temperatures for the region. That means conditions are not set up for a wet, cool summer.
But they aren't lining up to duplicate last summer's disappointment, either, when San Juan County received only a tiny amount of the rainfall it typically draws over a three-month period. The near-daily afternoon thunderstorms that are the hallmark of monsoon season never materialized in the summer of 2019, plunging the county back into a drought from which it had escaped only a few months earlier.
San Juan County received only 0.13 inches of precipitation during June, July and August of 2019, according to The Daily Times archives. Church managed to issue a wisecrack when asked if he was confident the region was going to escape that fate this year.
"I'm not sure we could end up being worse than last year," he said. "It's a low bar."
Last summer's hot-and-dry weather in the Southwest was a function of the so-called "Four Corners High" — a high-pressure system that typically sets up over the region — failing to slide east and allowing a deep southerly flow to push into New Mexico.
"That upper high just wouldn't budge," Church said. "It was centered here and stayed parked over New Mexico. That's not a good thing because then the monsoon moisture gets pushed off to the west and southwest and misses the desert Southwest completely."
Church doesn't see the same thing happening this year, even though summer monsoon seasons in the American Southwest, with a few exceptions, have been increasingly disappointing for the last 15 years or so. In fact, he said he and his colleagues have taken to calling those dud years "nonsoons."
The long-term trend pushing that change, he said, largely can be attributed to global warming. Church said the rapid warming of the Earth's poles has impacted the jet stream, making it less predictable and more volatile. He described the jet stream as the steering mechanism for the subtropical moisture that feeds monsoon storms, so changes in its behavior will impact where that moisture goes.
"It's not behaving like it has in the past, due mostly to climate change," Church said.
Despite the lack of prime conditions for monsoon storms this summer, Church said it isn't beyond the realm of possibility that the Southwest could still wind up having a good season, especially if the eastern tropical Pacific Ocean begins to cool and develop thunderstorms. That would draw the jet stream farther south and closer to the West Coast, he said.
If that happens, "We could be on the wetter side, we hope," Church said.
As for the timing of the monsoon, he said it should arrive right on time during the first week of July. He said signs of a southerly plume coming up to southern and eastern New Mexico from moisture pools in Mexico already are taking shape.
Church said the trend toward weaker monsoon seasons has been around for approximately 15 years, with 2006 and 2011 serving as notable exceptions. And he dismissed the notion that the Southwest might be "due" for a good monsoon season after so many years of light precipitation.
"It's more of a crapshoot every year," he said. "You like to think there's a balance, but that doesn't seem to be the case when you study year by year. … We've been down (in precipitation) for a long time, and (a return to wetter conditions) hasn't come to pass."
Whatever moisture falls from the sky this summer certainly will be greeted with excitement in San Juan County, most of which is locked in severe or extreme drought, according to the U.S. Drought Monitor. Only a narrow corridor in the western portion of the county has escaped that fate, with conditions there classified as being in moderate drought or an abnormally dry state.
Most of the eastern-most portion of San Juan County is in extreme drought, the second-worst category listed on the U.S. Drought Monitor. That section is part of a "curtain" of drought that covers parts of the five northern-most counties in the state — San Juan, Rio Arriba, Taos, Colfax and Union.
Mike Easterling can be reached at 505-564-4610 or email@example.com. Support local journalism with a digital subscription.