Triple-digit heat to put October record in jeopardy in Phoenix
September-like heat is underway across the Southwest, AccuWeather meteorologists say. The unseasonable heat will challenge daily record highs in several locations.
"Strong high pressure will build into the West, leading to significant warming over much of the West," AccuWeather Senior Meteorologist Heather Zehr said. "The peak of the heat for much of California will be Thursday, but over the interior West, Thursday and Friday will be similarly hot," added Zehr.
Cities like Los Angeles and San Francisco are forecast to both reach the mid- to upper 80s F on Thursday, which is roughly 10-15 degrees above historical averages.
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Forecasters urge residents wanting to spend time outdoors throughout the week to stay hydrated and take measures to prevent heat-related illnesses.
While Phoenix is no stranger to the heat, this stretch of heat will be noteworthy for this time of year. On Monday, Phoenix recorded a high of 105 F, which not only broke the daily record but is also the latest occurrence of 104 F or higher on record. The previous record for the latest 104-plus reading was back on Oct. 10, 1991, when 105 F was recorded.
AccuWeather meteorologists say that there is another shot to break the latest occurrence of 105-degree heat in Phoenix, as high temperatures are expected to climb to within a couple of degrees of that threshold on Thursday. The daily record high for Thursday is 101 set in 2003. More record-challenging daily highs and late-season high-temperature marks are possible on Friday and Saturday.
With daytime highs forecast to hit 100 each day through Saturday, this will likely bring the total number of days with temperatures over 100 degrees this year for Phoenix to 134, which would be just 12 days short of the record of 145 days set in 2020.
Phoenix could also come close to the October record for the most days of 100 degrees or higher. The current record is 15 days, which was set in 1991. As of Tuesday, Phoenix has recorded eight days of temperatures over 100 degrees during October.
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Forecasters say a pattern change is coming next week that will end the stretch of unseasonable heat. A major dip in the jet stream is expected across the western U.S., bringing temperatures down as much as 25 degrees compared to highs this week, ushering more fall-like weather to the region. There are even some early indications that the first significant snow may occur next week across mountainous areas in the region, including the Sierra Nevada.
A heavy snowfall is possible with plummeting temperatures and gusty winds for portions of the northern Rockies as the coldest air of the season so far makes a move late next week.
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