‘September surprise’ could prevent driest monsoon season ever


Las Cruces could be in for its driest monsoon season ever, but there is a “glimmer of hope” if current weather conditions deliver a “September surprise,” said National Weather Service meteorologist Jason Laney, who is stationed in Santa Teresa.

Thunderstorms are occurring in higher terrains – the Sacramento Mountains northeast of Las Cruces and the Black Range Mountains to the northwest, Laney said. Those thunderstorms “produce a cool outflow that spreads out to the lowlands,” including Las Cruces, and that “deep moisture in the atmosphere is the first and most important feature of monsoon rainfall,” he said.

The local monsoon season, officially June 15-Sept. 30, usually delivers about five inches of rain, which is 60 percent of the area’s annual total. This year, however, monsoons may produce only about an inch of rain – “a very disappointing number for us,” Laney said.

A monsoon is a seasonal reversal of wind. Rainfall is a byproduct.

The driest monsoon season on record is 1.17 inches in 1948, Laney said. Weather records date back to the late 1800s.

The culprit this year is “El Niño,” a weather pattern (winds and sea-surface temperatures) in the equatorial Pacific Ocean that impacts weather around the world.

“The atmosphere is battling itself,” Laney said. “You’ve got so many different controls trying to push the moisture our way. El Niño says, ‘Send it somewhere else.’ That’s what we see happening.”

The more than 100 weather models NWS is currently running include many predicting a half-inch of rainfall in this year’s monsoon season, a few showing no rainfall at all and some (the glimmer of hope) forecasting up to two inches of rain, said Laney, who has been forecasting weather for 34 years.

September “could bring some of that moisture our way,” he said. “It makes a tremendous amount of sense.”

This summer, every local heat record has been broken except for the one-day high temperature, Laney said.

The record high, 110 degrees, was recorded in Las Cruces June 28, 1994, he said. This year, Las Cruces reached 109 on both July 20 and Aug. 7.

Las Cruces has set records for total number of 100-degree days, consecutive days of 100 degrees or higher and days over 105 degrees,” Laney said.

“It has definitely been a record-breaking summer,” Laney said.