At this point in the week long event, the pattern was becoming repetitive with nocturnal MCS's developing over the Mogollon Rim and pushing southward off the rim into the lower elevations during the early morning hours. The night of July 29th into July 30th was no different. The synoptic pattern was very similar to previous nights. A cut off upper level low pressure system was located near Albuquerque, NM, just a bit east of its location the past few days. There was a weak inverted trough over northern Mexico and a large scale trough across the eastern pacific. Water vapor imagery showed a stretching deformation zone across much of Arizona between the upper level low over New Mexico and the trough over the eastern pacific.

Once again on July 29th there was some scattered diurnally driven convection. This time it was primarily located across Santa Cruz and Central Pima County which includes the Tohono O'odham Nation. These slowly southeast moving cells produced several inches of rainfall making portions of highway 86 impassable over the Tohono O'odham Nation due to flash flooding.

As the evening progressed, it was clear there was going to be more activity pushing south to southeast off the Mogollon rim. The flow aloft during the 29th into 30th was more north-northwest compared to a northerly flow during the prior nights. This generally put the areas from Tucson eastward under the gun for heavy rainfall. The first major nocturnal thunderstorm activity moved into Southeast Arizona from the north after midnight. While this MCS wasn't as organized as the prior night, with the considerable moisture in place, the thunderstorms were still extremely efficient rain producers. Within the Tucson Metro Area the heaviest rainfall fell on the north and east sides of the city including the Santa Catalina Mountains. Both Mt. Lemmon and Sabino Canyon recorded about 1.5 inches of rain overnight. Rainfall amounts in the city were generally less than one inch.
This area of thunderstorms consolidated better as it moved south to southeast into Santa Cruz and Cochise County where heavy rainfall fell as well. River flooding continued to be a major issue the morning of July 30th especially along the Santa Cruz River in Pinal County including Eloy.