Dust Storm in Northwest Pinal County, Arizona

Visibility reduced to approximately 300 feet near the Intersection of SR-84 and Stanfield Road in Stanfield due to dense blowing dust from thunderstorm outflow winds. No accidents nor injuries were reported.

With the subtropical high pressure system situated across northern AZ, the steering flow was from the east. Riding underneath the subtropical high was an easterly disturbance near the International Border, which helped enhance the easterly flow at mid-levels upwards of 25 kts as well as the forcing for ascent. MLCAPE values between 1000-1500 J/KG and DCAPE values in excess of 1500 J/KG resulted in an environment favorable for strong to severe downburst winds. The enhanced easterly flow, which increased the vertical shear upwards of 25-30 kts, contributed to the overall storm organization and thus for most of the thunderstorm activity to become severe. Thunderstorm activity first developed across the higher terrain areas of eastern and southeastern AZ with additional activity developing over the lower deserts via outflow boundaries.