Metro Denver, the Interstate 25 corridor and the northeastern Plains are bracing for dangerously high temperatures Friday and Saturday, as a heat dome is building up over Colorado on Thursday.

The National Weather Service in Boulder has issued a heat advisory for much of north-central and northeastern Colorado for a 31-hour time frame, one in which high temperatures will reach into the upper 90s and low 100s on Friday and Saturday, and mid 90s on Sunday.

The European Center for Mid-Range Weather Forecasts predicted that the high pressure ridge to park itself over the New Mexico-Colorado border into Saturday morning, then shift eastward into the lower Mississippi River valley through Monday night, creating the hot temperatures in Colorado.

What’s a heat dome?

According to the NWS, a heat dome occurs when a large area of high pressure in the upper atmosphere acts as a reservoir that traps heat and humidity and confines it to a certain area.

Colorado doesn’t usually suffer from high humidity levels. However, “dry-heat” can be a problem because human sweat evaporates faster in dry climates compared to humid ones, the NWS said.

Details about the heat advisory in Colorado: 

• What: High temperatures near 100 degrees across the I-25 urban corridor, and up to 103 across the eastern plains.

• Where: All of the I-25 urban corridor, northeast and east central plains of Colorado.

• When: The worst heat will be from 11 a.m. to 6 p.m. both Friday and Saturday.

The NWS in Boulder forecasts that Denver has a 60% chance of a high temperature greater than 100 degrees on both Friday and Saturday; in Greeley in Weld County, it’s a 70% chance on Friday and 60% chance on Saturday; and for Fort Morgan in Morgan County, it’s a 96% chance on Friday and 85% chance on Saturday.

Extreme heat conditions can lead to higher energy bills and put a strain on the electric system. The Colorado Public Utilities Commission urges taking steps to stay safe and save energy with extreme heat forecasts for Colorado.

Here are some ways to help keep the temperature down inside your house and lower bills:

• Open interior doors to help cool air circulate through the space
• Keep drapes and blinds closed during the heat of the day
• Check your AC filters and coils to see if they need to be cleaned or changed to improve efficiency
• Only run your washer and dryer, and other major appliances, before or after the hottest part of the day to help maintain indoor temperatures and ease the strain on cooling systems that are running on high.

Although these actions help, the most important thing is to stay cool, the PUC said. Heat is the leading weather-related killer in the United States and concern over high energy bills shouldn’t be a reason to let homes reach a dangerous temperature.

Denver Gazette reporter Scott Weiser contributed to this report.