Brace yourself for sweltering temperatures this week, Boise. Just how hot will it get?

The Treasure Valley is going to bake in a heat wave, with scorching temperatures over 100 degrees starting Tuesday and continuing into early next week.

Highs in Boise will be 5 to 10 degrees hotter than usual and will max out at around 105 degrees, said Stefanie Henry, a meteorologist with the National Weather Service in Boise. Cities in the lower Treasure Valley, like Ontario, Oregon, could see even higher temperatures, Henry said.

Temperatures across the region could reach up to 107 this weekend, according to a National Weather Service forecast. The National Weather Service has issued a heat advisory for Southeast Oregon and portions of Southwest Idaho from 12 p.m. MDT on Wednesday to 9 p.m. MDT on Saturday.

Henry said a high-pressure system to the southwest is causing the heat.

“We have a very strong high pressure that originally developed over down by Arizona, eastern California, Nevada and Utah, and that high pressure has strengthened northward into Idaho and Oregon,” Henry said. “That’s leading to just more hot conditions.”

“Monsoonal moisture” coming from Southern California and Arizona also could contribute to isolated thunderstorms later this week.

Henry added that low temperatures this week are also higher than usual.

“So right now we have lows around 70 degrees, which is a little bit cooler,” Henry said, “but it’s not enough to completely cool people off, especially if they don’t have air conditioning.”

How does this summer’s weather stack up?

Last summer, the National Weather Service recorded 18 days in the 100s. So far, there have been nine days in the 100s this year. But summer is far from over.

“The average temperature is cooler than last year,” Henry said.

The Treasure Valley is in a drought, but Henry said conditions are better than they were last year. The region is “abnormally dry to moderate” right now, compared to last year’s “moderate to severe drought” conditions. Henry said a wetter spring helped improve the conditions in the Treasure Valley.

Henry said those conditions should help reduce the risk of wildfires in Idaho. Right now, three major fires are burning in Central Idaho.

“Our forests are having better fuel moisture this year than they did last year,” Henry said. “That will help with fire growth in the forest for Idaho.”

Staying cool during the heat wave

Heat can pose serious health and safety risks, especially among compromised groups.

“We would like to promote people staying hydrated, as well as keeping their their vulnerable populations cool, such as young children, elderly and pets,” Henry said.

She added that people should make sure they have access to air conditioning, whether at home or at cooling shelters. Cooling shelters in Boise include Boise City Hall, Cathedral of the Rockies, Corpus Christi House, Our Path Home Outreach, the Boise Public Library and the Downtown Boise YMCA.

Other precautions to take against the high temperatures include wearing light, loose clothing and keeping pets away from hot pavement that could hurt their paws.

High temperatures elevate heat stroke and exhaustion risk

Henry advised Treasure Valley residents to look out for signs of heat stroke and heat exhaustion. Both can result from exposure to hot temperatures like the ones forecast this week, but they have different symptoms.

Heat exhaustion can cause dizziness, thirst, sweating, nausea and weakness. People experiencing heat exhaustion may also have cool, pale and clammy skin, and a rapid, weak pulse.

If you think someone is showing signs of heat exhaustion, move them to a cooler area, loosen their clothing, give them water and monitor their symptoms.

Heat stroke is more dangerous and may cause confusion, high body temperature, headache and even loss of consciousness. A person experiencing heat stroke may have stopped sweating and have a rapid, strong pulse.

If you believe someone is experiencing heat stroke, call 911 immediately.