Thunderstorm Wind in Yuma County, Arizona

Semi blown over on I-8 near Tacna. Timing estimated from radar and reports.

The environment across south-central and southwest Arizona on August 25th was primed for strong to severe thunderstorms with very moist and unstable conditions in place. The synoptic pattern featured a subtropical ridge of high pressure centered over northern New Mexico, promoting southeasterly flow aloft over Arizona and allowing for moisture advection into the region, while a Pacific trough to the west promoted upper level divergence over the region. The broad ascent over the region combined with MLCAPE values around 1,000 J/kg and DCAPE values also around 1,000 J/kg provided an environment conducive to strong to severe thunderstorm development. Daytime heating allowed for continued destabilization with thunderstorms initiating near the southern Arizona/Mexico international early in the afternoon. These thunderstorms then raced toward the north through the afternoon, producing very strong outflow winds that resulted in a large wall of dust. The large dust storm continued to progress toward the north into the Phoenix metro by late afternoon/early evening. The dust storm resulted in widespread visibilities under a quarter mile. The strong outflow boundary responsible for the dust storm led to additional thunderstorm development with some of these thunderstorms becoming strong to severe in the Phoenix metro. No injuries were reported during this event.