Nyyokki Powers, left, her daughter Anyiah, 9, and their dog Bruno take shelter from the sun at Udall Dog Park, 7290 E. Tanque Verde Road. An excessive heat warning for Tucson will be in effect from Thursday to Saturday this week.

 Rebecca Sasnett / Arizona Daily Star

Tucson temperatures will approach record highs this week, with Friday expected to reach nearly 110 degrees, weather officials said.

An excessive heat warning will be in effect from Thursday to Saturday this week as high temperatures go back to triple digits starting Wednesday.

May’s high temperatures have remained in the 90s and sometimes high 80s since May 9.

But as June approaches — the hottest month of the year in Southern Arizona — a high pressure system over the Southwest will bring temperatures up in the Tucson area, along with the rest of Arizona, southern Nevada and New Mexico.

Wednesday’s high is expected to be between 102 and 104 degrees. Thursday’s high is expected to be between 103 and 106 degrees, said Jeremy Michael, a meteorologist with the National Weather Service in Tucson. The record high for Thursday was set in 2000 at 107 degrees.

Friday’s high is forecast between 106 and 109 degrees and Saturday’s temperatures are expected to reach 106, Michael said.

The record high for Friday is 111 degrees and Saturday’s record high is 110 degrees, both set in 1910.

“With the heat we’re expecting, while certainly it’s going to be hot, it looks like each day we will be below records but within a few degrees of records so still unseasonably hot,” Michael said.

The National Weather Service in Tucson uses the Tucson International Airport for its official forecast point, but it’s often a degree or two higher in the downtown area or further north toward Marana, Michael said.

The heat is above average for this time of the year but the heat usually ramps up in June, Michael said.

As of Monday, May temperatures were 4.1 degrees above normal. Most of that is due to the week of May 5 to May 8, Michael said.

The expected heat in coming days will increase the above normal average temperatures for the month.

“May into June is some of our hottest, driest time of the year,” Michael said.

“Then as the monsoon comes in temperatures moderate a little bit and we get more moisture and showers and thunderstorms and clouds and that helps.”

Isolated showers are expected in northeast Arizona this weekend, in the White Mountains area, with a chance of light showers around Tucson, most likely in northeast Pima County early next week, Michael said.

“Most of these will be on the drier side,” he said. “This won’t be anything like the monsoons where we’re suspecting substantial rains.”

The Pima County Department of Environmental Quality Clean Air Program issued an air pollution advisory for Tuesday, as there was a potential for higher levels of ground-level ozone pollution.

People who are more sensitive to ozone, including children, people who are active outdoors and those with respiratory diseases, can experience shortness of breath, coughing and breathing discomfort during increased levels of pollution.

Several pollutants contribute to the elevated levels of ground-level ozone, including vehicle emissions, industrial pollutants, gasoline vapors, and some plants and trees, all of which react to solar radiation, said Beth Gorman, manager of Pima County’s Clean Air Program.

While temperatures are expected to increase later in the week, the Arizona Department of Environmental Quality forecast shows ozone pollution will decrease through the week, with Tuesday being the only day where the levels were dangerous in the Tucson area.

Mid-level winds are expected to move pollution out of the Tucson metro area after Tuesday, Gorman said.

As the hottest time of the year approaches, Michael said people should remember to drink plenty of water, exercise in the morning or evening, wear a hat and sunscreen, and to never leave a pet or person in a vehicle for any amount of time.

Signs of heat-related illness include cool, moist, pale or flushed skin; heavy sweating; headache; nausea; dizziness; weakness; or exhaustion.

Heatstrokes can be life-threatening. Signs of a heatstroke include changes in consciousness; hot and red skin; vomiting; and high blood pressure.

Animals can also suffer heatstroke. Heavy panting, inability to calm down, inability to get up, brick-red gums and a fast pulse are all signs a pet may be having a heatstroke.

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