Dust Storm in Kofa, Arizona

A Yuma proving ground station measured a visibility of less than 1/4 mile due to blowing dust in thunderstorm outflow.

A mid-level high pressure was situated across southern Nevada, with the local area under an northeasterly flow regime. At upper-levels, a disturbance moving northward out northern Baja California resulted in a diffluent flow, favorable for vertical ascent. The moisture and instability parameters were conducive to thunderstorm activity with PWATs 1.5+ inches and MLCAPE values ranging between 1500-2500 J/KG. As it is typical in a northeasterly flow regime, thunderstorms first began to develop along the Mogollon Rim early afternoon and then descended into the lower elevations during the mid to late afternoon hours, affecting the Greater Phoenix area and then tracking southwestward, affecting southwestern Arizona through the early evening hours.