Better late than never, the scattered showers Southwest Colorado has received for more than a week are indeed the arrival of the monsoon season – a relief to many as the seasonal rains stayed south of the Four Corners last year.
“What we’re seeing is a result of the monsoonal pattern that sets up this time of year, and at least for the next couple days we’ll continue to see a good chance of scattered showers. Monday is looking a little less likely for precipitation, but as we get into Tuesday, we’re going to see that push of monsoonal moisture from the south, and we’ll have a good chance of rain through the weekend,” said Kris Sanders, a meteorologist with the National Weather Service in Grand Junction.
The typical pattern for monsoonal rains will be followed for the upcoming week, with scattered rain showers likely in the afternoon. Sanders said showers could come earlier in the mountains, possibly coming as early as noon in the high country, with showers more likely in the valleys from 2 p.m. into the later afternoon.
A good idea for people looking to recreate in the San Juan Mountains, Sanders said, is to get started early and to be off the mountain by noon or 1 p.m. to avoid getting caught in a rain shower.
“‘Know before you go,’ is what we say,” he said. “It’s especially important if you’re in an area with no cell services. Tell people what you’re doing before you leave.”
Along with the monsoons will come an increased chance of flash floods, and Sanders said the Weather Service will examine the patterns daily and look to issue flash-flood watches when rainfall looks particularly heavy, especially over the 416 Fire’s burn scar and the burn scar of June’s East Canyon Fire.
Some days might have several waves of showers – with an early afternoon shower followed by showers in the evening or even at night – but Sanders said the afternoon has the best chance of thunderstorms and showers.
The current weather pattern is in a “classic monsoonal pattern” with a high pressure system over the southern plains of the United States that brings up moisture from the Gulf of Mexico and a low pressure system off the coast of California that brings in moisture from the Pacific Ocean.
Typically, from mid-July to early September, monsoons bring an increased chance of rain in Southwest Colorado and more broadly the southwestern United States.
The Climate Predication Center currently has a one-month outlook that expects normal levels of precipitation for the Four Corners.
“It’s tough to do long-range forecasting once you get beyond a week or so, it’s really difficult,” Sanders said.