Southwest Colorado has enjoyed cool weather accompanied by rains in recent weeks, but that trend will end this weekend.
A heat dome will park over Southwest Colorado beginning Friday with temperatures forecast in the 90s and even pushing into triple digits in some slightly more distant regions.
“Climatologically we’re under the monsoon and things tend to keep us a little bit cooler because of those showers, but as soon as we lose that shower activity, it gets hot quick,” said Lucas Boyer, a meteorologist with the National Weather Service.
National Weather Service forecasts call for low 90s in Durango and mid-90s in Cortez throughout the weekend and into next week, with temperatures in the high 80s in Pagosa Springs and mid-70s in Silverton.
“We’re looking probably triple digits across the lower-elevation valleys in western Colorado and eastern Utah,” Boyer said.
In Durango and Cortez, temperatures are forecast to be 5 to 10 degrees above normal.
A high-pressure system in the Southern Plains funneled moisture from the tropics into the Four Corners for weeks, but that phenomenon will give way to a heat dome moving in from the central U.S. that left millions of people under heat advisories and warnings earlier this week.
A heat dome occurs when a large column of warm air gets trapped under a high-pressure system. As the high pressure forces the air toward the ground, it compresses, heating the air further. Warmer temperatures dry out the ground further exacerbating the heat.
“With a substantial high (pressure system) building into the region, we kind of turn that moisture spigot off and then we start drying out,” Boyer said.
Parts of Southwest Colorado could see chances of showers and thunderstorms, according to National Weather Service forecasts, but it will be a marked shift from the above-normal rains of the last few weeks.
Once that moisture is gone, it will take consistent rain to replace, Boyer said.
Forecasts show the heat will be consistent through the weekend and into early next week with a break midweek. After that, the models are inconclusive, Boyer said.
However, the heat dome could remain in the area until mid to late July, according to The Washington Post.
Heat domes with scorching temperatures are not unusual even during Southwest Colorado’s monsoon, which typically starts around mid-July.
“These types of things are consistent with the monsoonal pattern. It comes and goes through the season,” Boyer said.
But, while not uncommon, they still prompt warnings from weather officials.
“We always caution folks to make sure to prepare for the weather conditions, but under extreme heat, water and proper sun protection is very important,” Boyer said.