Rain is expected to arrive this week in Southwest Colorado and drop high temperatures into the mid-80s, according to the National Weather Service.
There’s a 40% chance for scattered showers and thunderstorms Tuesday in Cortez, and a 70% chance Wednesday through Friday, said Erin Walter, a weather service meteorologist.
The pattern is not the typical setup to draw up monsoonal rain from the south, but it is enough to “pump in some high-moisture content” for Southwest Colorado, she said.
“Each afternoon, there is a good chance for showers, and in the higher terrain, it will be more widespread,” Walter said.
In Durango, there’s an 80% chance for rain Tuesday through Thursday, with showers likely Friday and Saturday.
The forecasts suggest a cooling trend this week because of the storms’ accompanying cloud cover.
A high-pressure ridge has created dry conditions north of Interstate 70 and helped to draw moisture to southern Colorado, the weather service said.
The strongest thunderstorms are predicted along the Uncompahgre Ridge and Dallas Divide in the San Juan Mountains, which could be the focus of localized flash flooding.
A high-pressure ridge is expected to push farther into the region this weekend and cut off the monsoon flow, Walter added, but there will be enough remnant moisture to spark a few mountain showers Sunday and Monday.
Monsoonal rainstorms have been sporadic for Cortez, hitting some areas of town and missing others, said Jim Andrus, National Weather Service observer.
Cortez is in a precipitation deficit and has had sweltering high temperatures.
July has seen just 0.22 inches of rain, or 18% of the 1.25-inch average for the month.
For the year, Cortez has seen 3.06 inches of rain, or about 50% of the normal 6.15 inches through July.
Cortez recently broke two daily heat records, Andrus said.
On July 23, the high was 102 degrees in town, beating the previous record of 100 degrees for that date in 1931.
On July 24, the high in Cortez was 99 degrees, breaking the previous record of 98 degrees for that date in 2018.
Western Montezuma County and western Dolores County are both rated in the category of D3 Extreme Drought, the fourth-highest drought category out of five on the U.S. Drought Monitor.
Southern La Plata County is rated as a D2 Severe Drought, the third-highest of five categories. Northern La Plata County is at D1 Moderate Drought, or the second-highest of five categories.