Heat dome expected to push Summit County temperatures into the 90s this weekend

A heat dome is expected to bring unusually hot temperatures to Park City and Summit County through the weekend. Photo: Nick Fewings

PARK CITY, Utah — A strengthening area of high pressure is expected to settle over Utah this weekend, pushing Park City temperatures into the mid-90s and increasing the risk of heat-related illness.

The National Weather Service in Salt Lake City said Wednesday that a broad ridge of high pressure will shift over the West beginning Thursday, with its center moving directly over Utah during the weekend. The pattern will draw drier air into the state, reduce thunderstorm activity and allow temperatures to rise.

Park City is forecast to reach 82 degrees Wednesday before warming to 89 Thursday, 93 Friday and 96 Saturday and Sunday, according to the weather service’s forecast Wednesday morning. Overnight lows are expected to rise from 57 degrees Wednesday night to 64 degrees Saturday night.

Forecasters expect the heat to peak Saturday. The weather service said it has higher-than-usual confidence that maximum temperatures will be very hot Saturday and Sunday. However, uncertainty remains about nighttime temperatures and how much overnight relief northern Utah will receive.

The weather service had not issued an Extreme Heat Watch for northern Utah as of Wednesday morning. Forecasters said they were holding off because of uncertainty over the duration of the event and how warm overnight temperatures will remain.

The pattern is commonly described as a heat dome. NOAA explains that heat waves can form when high pressure in the middle atmosphere strengthens and remains over a region for days or weeks. The high pressure acts as a cap, causing air to sink and limiting the clouds and storms that might otherwise provide relief. Heat then builds near the ground.

Wednesday is expected to bring a final round of monsoon moisture before the drying trend begins. The weather service forecast scattered showers and thunderstorms in Park City, with a 50% chance of precipitation during the day and a 20% chance before midnight.

By Thursday, sunny and increasingly hot conditions are expected to take hold. The weather service said the greatest heat-related health risks will be in Utah’s valleys. Still, Park City’s forecast highs will also be unusually hot for a community at roughly 7,000 feet.

The Centers for Disease Control and Prevention advises people to move outdoor activities to cooler parts of the day when possible, take breaks in the shade, and drink water regularly. People who are pregnant, 65 or older, very young, working or exercising outdoors, or living with certain chronic conditions may face greater risks during hot weather.

The CDC recommends checking on people who live alone or have chronic medical conditions.

The ridge may weaken and move south early next week as a storm system passes through the Pacific Northwest. The weather service said that could provide some relief in northern Utah, although forecast models remain uncertain about how much temperatures will fall.