Afternoon thunderstorms in the deserts of southern Arizona, especially during the summer months, are primarily due to the North American Monsoon. This seasonal weather pattern typically starts in late June and lasts through September, bringing a noticeable shift in wind direction and moisture levels.

During this period, moist air from the Gulf of California and the Gulf of Mexico flows into the typically dry desert regions. The intense summer heat causes the ground to heat up rapidly, leading to strong surface heating. This heating creates rising warm air, which combined with the incoming moist air, leads to the development of towering cumulonimbus clouds.

The combination of intense surface heating, moisture influx, and atmospheric instability during the afternoons creates the perfect conditions for thunderstorms. As the day progresses and temperatures peak, the likelihood of storm development increases, resulting in those characteristic afternoon thunderstorms.

I witnessed this phenomenon in the summer 2018, and the experience was majestic and sometimes terrifying.

This image is part of my atmosphere series.