This morning's analyses show a shortwave in the subtropical easterly flow to be over central Mexico . This feature will brush across southern portions of Arizona late tonight and tomorrow. A weak McCollum Type II severe thunderstorm pattern is in place, the outlook is for a slight chance of both storms and severe late this afternoon - especially in southeast portions of Zone 8. The chance for severe and storms in the Valley itself is probably somewhat higher tomorrow as the frontal zone weakens and up Valley flow returns. P chart of the 12 UTC sounding from Luke Air Force Base on August 5, 1994.
Wind speeds are in knots.
The small box indicates the location of Phoenix, and the Salt and Verde River Basins are outlined. This afternoon storms on the Rim developed quickly to the southeast and moved into the Valley around 6 PM with some light rain, frequent lightning, and strong outflows. There were numerous downbursts detected by the WSR-88D and a number of reports of wind damage. There was substantial blowing dust and apparently one or two storms in the Valley were actually rooted into the boundary layer by the strong outflow forcing from the area of the Superstitions. Between 5 to 6 PM a very impressive and probably severe storm developed south of Ajo and moved to the west-northwest.