Better late than never, the scattered showers Southwest Colorado has received the past two weeks 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,” said Kris Sanders, a meteorologist with the National Weather Service in Grand Junction.
“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.”
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 11 a.m. or noon in the high country, with showers more common in the valleys from 1 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 rapidly forming 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 service. 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 burn scars of the 416 Fire and the 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.
According to a statement from the National Weather Service in Grand Junction, “Showers and storms will be most favored in the central and southern mountains, and can produce locally moderate to heavy rainfall. Additionally, showers and storms have the potential to be slow-moving. This would increase the risk for flash flooding, particularly near burn scars.”
The weather service said residents of Southwest Colorado should check regularly for the next week for possible flash flood watches.
The chance for thunderstorms in Durango rises to 70% Wednesday with a 50% chance on Thursday.
In Cortez, the chance of thunderstorms on Wednesday is 40% and the chance of scattered showers increases from 30% Thursday to 40% Thursday night.
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,” Sanders said.
parmijo@durangoherald.com
