Southwest Colorado anticipated to obtain moisture from ‘atmospheric river’ transferring in from Pacific – The Durango Herald
The weather service says rain is needed as winter is drier than normal
The mountains of La Plata and San Juan are bare on the southern slopes on Saturday, but Monday through Wednesday the mountains should be covered in snow as a weather system moves through the area. (Jerry McBride / Durango Herald)
A large amount of moisture from the Pacific Ocean, known as the “atmospheric river,” flows into southwest Colorado.
“Basically, it’s this heavy cloud of moisture that comes in from the Pacific,” said Erin Walter, a meteorologist for the National Weather Service in Grand Junction. “It’s like this continuous stream, almost like a jet, but in the form of moisture.”
Over the weekend, the atmospheric river dumped over 5 inches of rain in the San Francisco area, Walter said.
Most of the moisture from the storm system in California is drained over the Sierra Nevada and Great Basin, with southwest Colorado receiving the last bit of rainfall on Tuesday.
“We’re not going to see snowflakes like we did in the Sierra Nevada, but we’re going to see some precipitation,” said Walter.
Southwest Colorado has warm conditions that will be a big factor in how much rainfall the area falls, Walter said.
“We see higher amounts of snow on Tuesday morning, and then, when the system goes through, a little colder air will come in behind it,” said Walter.
A cloud of moisture known as the atmospheric river is moving across the states and will bring rain to southwest Colorado on Tuesday. (Jerry McBride / Durango Herald file)
Cities along US Highway 160 should expect about a quarter of an inch of rain on Tuesday, with some areas potentially seeing higher, localized rainfall of about half an inch.
“For Durango, Cortez, and Pagosa Springs, I would expect at least a quarter of an inch,” said Walter.
As for snow, Silverton is expected to get about an inch of powder in town, with about 5 to 20 inches in the higher elevations of the San Juan Mountains.
The National Oceanic and Atmospheric Administration released its winter outlook for temperature, precipitation and drought on Thursday. This is the second year in a row La Niña, according to NOAA. The seasons of La Niña are caused by above-average sea surface temperatures in the tropical Pacific.
“The southwest is sure to remain a region of concern as we anticipate below-average rainfall with the drought continuing in most areas,” said Jon Gottschalck of NOAA’s Climate Prediction Center.
In southwest Colorado, temperatures are expected to be 40 to 50% higher than normal, rainfall 33 to 40% lower than normal, and drought conditions expected to worsen.
“Any moisture is definitely welcome,” said Walter.
njohnson@durangoherald.com
