Record-breaking weekend heat and a pounding storm early Tuesday served as a reminder of what Tucson is about to lose: the 2023 monsoon season.
The National Weather Service in Tucson proved to be accurate with its excessive heat warning over the weekend.
Saturday reached 108 degrees. Sunday’s 111 degrees was the new all-time September temperature record in the city’s history.
With temperatures reaching 103 degrees Monday, the Old Pueblo has now seen seven days of 100-plus-degrees this month. The average for the month is eight days, the weather service says.
Tucson has reached highs of at least 100 degrees 77 times so far this year. That’s nine more than the usual number of triple-digits days. The city’s weather records date back to 1895.
Tucson’s average high for this time of year is about 96 degrees.
A storm early Tuesday brought heavy rainfall to the Tucson metro area and western portions of the city.
As of noon Tuesday, Midtown Tucson recorded from .04 to .12 inches of rain early Tuesday, the weather service said. Areas near River Road saw about .20 inches of rainfall while the Catalina Foothills received about .40 inches.
The most affected areas were in Oro Valley and the Catalina Mountains, where was recorded to be anywhere from .4 to .63 inches, officials say, while the top of Mount Lemmon recorded 1.06 inches of rainfall.
Tuesday’s rainfall totals were not yet final, said Gary Zell, a meteorologist with the weather service said early in the day, noting it was still possible for some more rain in the region.
Through Monday, the 2023 monsoon season has brought 4.39 inches of rain to the region, Zell said. The normal amount of rain expected through Sept. 11 is 4.99 inches.
A “substantial drying period” is on Tucson’s immediate horizon, one that Zell says could spell the end of this year’s monsoon season.
“[Significant drying occurs when] westerly flow pushes moisture that’s in place,” Zell said.
“We get that this time of year, whether it be the beginning, middle or end of September …. The one wrinkle that could throw a wrench into that is any tropical systems that develop off the western coast of Mexico and move north.”
The weather service here expects storm chances to be about 40% Wednesday for midtown Tucson.
After that, Zell said Tucson’s storm chances are almost surely finished ahead of the official end of the monsoon season, Sept. 30.
“You can get moisture a couple different ways but once it dries out, usually that signifies the end of the monsoon season,” he said.
High temperatures of about 98 and 97 degrees are expected Saturday and Sunday.
Thursday night's storm lit up the sky west of Tucson.
