The weather has turned in favor of more moisture for Southwest Colorado into September, signaling a possible drought-buster.
“It’s one of our better monsoons we have seen in awhile and is producing deep moisture, often for three or four days in a row,” said meteorologist Chris Cuoco, of the National Weather Service.
The Southwest monsoon is a seasonal shift in wind flow from the tropical south that funnels moisture into New Mexico, Arizona, Colorado and Utah. It has occurred regularly since 1900.
Each July, the Bermuda high pressure system repositions over the Gulf of Mexico, causing winds to shift around it and producing the monsoon.
“You can see the plume of moisture on satellite, drawing moisture from the eastern Pacific, then delivering thunderstorms along western Mexico and into the western U.S.,” Cuoco said.
Also, El Niño, – characterized by warming of the eastern equatorial Pacific Ocean – has begun, which can bring moisture to western Colorado.
Cuoco rates El Niño as “strongly warmer,” with surface temperatures rising 3 degrees Celsius.
“It’s sizing up to compare with the strong El Niño in 1997 and 1998 that brought record moisture to the western U.S.,” he said.
El Niño doesn’t guarantee moisture for Southwest Colorado, but it can increase its chances.
“Because the El Niño is matching up with the monsoon, it signals higher than normal precipitation,” Cuoco said.
In 1998, a strong El Niño year, Cortez saw above-average precipitation, said local weather observer Jim Andrus.
This year, Cortez has experienced record rainfall. May was 290 percent of normal, at 2.41 inches. June, typically the driest month, was 583 percent of normal, at 2.33 inches, and July is at 176 percent of normal, at 2.25 inches.
The National Oceanic Atmospheric Administration also forecasts the Four Corners to be wetter than average in July through September. According to the U.S. Drought Monitor, Southwest Colorado went from severe to moderate drought in April to the current no-drought status, based on total precipitation for 2015.
