Storm Chances Fade As Dangerous Heat Builds in Phoenix

PHOENIX, AZ — Arizona is in for a dramatic weather whiplash this week.

After a chance of monsoon storms Monday and Tuesday, including a slight possibility of thunderstorms reaching the Phoenix metro, forecasters say the state is on track for a sharp turnaround that could bring dangerous, widespread heat by the weekend.

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According to the National Weather Service in Phoenix's Monday morning forecast discussion, storm chances will increase through Tuesday, especially across Arizona's higher terrain.

While the mountains are expected to see the most widespread activity, isolated storms could also drift into the south-central Arizona deserts.

For Phoenix, forecasters are giving Monday evening a 20% to 30% chance of thunderstorms. Whether storms develop over the Valley will depend on a surge of Gulf moisture and outflow boundaries left behind by earlier storms.

Communities in the higher elevations could see wind gusts up to 40 mph along with pockets of heavy rainfall. Across the lower deserts, the primary threats are strong winds and areas of blowing dust. Scattered showers and a few thunderstorms may linger overnight into Tuesday morning before storm chances gradually diminish across the Phoenix area by Tuesday afternoon and evening.

Temperatures will remain relatively manageable through Tuesday, with only Minor to Moderate Heat Risk expected. Highs across central and eastern Arizona are forecast to stay below normal for now, while southwest Arizona and southeast California could begin warming above seasonal averages as early as Tuesday. Overnight lows in the lower deserts are expected to remain in the low to mid-80s.

That break from the heat won't last.

As drier air moves into the region during the second half of the week, monsoon storm chances are expected to fade quickly, dropping to only a slight chance by Thursday. At the same time, temperatures will climb rapidly.

By Thursday, the focus shifts from storms to potentially dangerous heat.

The National Weather Service expects areas of Major Heat Risk to develop Thursday, with a high likelihood that widespread Major to Extreme Heat Risk will settle in by the weekend. High temperatures in the Phoenix area are forecast to reach 110 to 113 degrees, while western desert communities could see highs between 113 and 116 degrees.

Forecasters say an Extreme Heat Watch will likely be issued within the next day or two if the forecast remains on track.