“A more persistent high-pressure ridge than expected over the Four Corners is blocking the southerly monsoonal flows,” said Jim Andrus, a Cortez weather observer for the National Weather Service. “The dry spell will continue into next week.”
July and August were both below normal for precipitation for Cortez, he said.
July saw just .45 inches of rain, or 35 percent of the normal average of 1.28 inches. So far, August has seen just .57 inches of rain, or 39 percent of the normal 1.48 inches.
The lack of moisture has put southwest Colorado into the “abnormally dry” category on the U.S. Drought Monitor, the least severe of five drought levels.
“Far into the monsoon season, the rains continue to fail in the Southwest,” according to the Drought Monitor. “Only the abundant precipitation that fell last winter is keeping substantial impacts at bay so far this summer.”
Year-to-date precipitation in Cortez is at 11.2 inches, or 144 percent of average, thanks to the above-average snowfall in late winter. But the high percentage continues to drop as the dry spell continues.
There is still a chance the Four Corners could get a shot of late season monsoon rains, Andrus said, if the high pressure ridge shifts to the east.
The September forecast hints at a chance for slightly above-average precipitation, said Jeff Colton, a meteorologist with the National Weather Services, as the early winter northwesterly storms drop our way.
Meanwhile, the National Oceanic and Atmospheric Administration announced last week that the El Niño weather pattern — a warming of the equatorial Pacific Ocean that contributed to the extra snowy Southwest winter — has ended.
It’s in a neutral pattern that is neither El Niño, or its opposite, La Niña, which is characterized by cooler Pacific temperatures with an atmospheric tendency to push winter storms toward the Northwest.
According to NOAA’s Climate Prediction Center, there is a 55 percent chance the neutral pattern will continue through the winter, a 30 percent chance El Niño will return, and a 15 percent chance La Niña will form.
“There is a sign that a weak El Niño may come back in late winter, bringing potential for wetter spring storms,” said Colton.