A powerful storm system moving across the West Coast tapped into a plume of humid air over Arizona, producing intense thunderstorms and prompting a rare Tornado Watch in the state, according to the FOX Forecast Center. Parts of Arizona including Flagstaff and Prescott were placed under a Level 3 of 5 severe thunderstorm risk. The threat included damaging, egg-sized hail and possible tornadoes, FOX Weather said.
The Tornado Watch marked the first such watch in Arizona in 16 years, the FOX Forecast Center reported. A Tornado Warning was also issued for part of Yavapai County on Wednesday morning. A Severe Thunderstorm Watch and a Level 2 severe storm threat covered the Phoenix metro area, including Phoenix, Glendale, Chandler and Scottsdale, FOX Weather said. Flood Watches remained in effect through Thursday for much of Arizona and for parts of southern Utah, southwestern Colorado and western New Mexico.
Heavy rain from the same system soaked parts of Southern California and caused flash flooding, especially over recent wildfire burn scars, FOX Weather reported. The FOX Forecast Center warned that more thunderstorms could develop as the system shifts east toward the Rockies.
Flood Risks And Broader Seasonal Implications
A renewed flash flood threat was reported for the Four Corners region on Thursday. In southeastern Colorado a separate flash flood threat, rated Level 3 of 4, was near the Ferris Fire burn scar, where the FOX Forecast Center said three to five inches of rain was possible. The center said those totals increase the risk of rapid runoff and dangerous flooding on and below burn scars.
FOX Weather noted the Level 3 severe threat for parts of central Arizona is notable because NOAA adopted the five-tiered risk scale in 2015 and similar October severity is uncommon. Forecasters cautioned that this pattern of storminess could presage a wetter and stormier winter because of an impending Super El Niño. The FOX Forecast Center pointed out that two of the past three Super El Niño winters, 1997–1998 and 2015–2016, brought significant severe storm outbreaks across the Gulf Coast, Southeast and Southern Plains.
Officials and forecasters urged vigilance where Flood Watches, Severe Thunderstorm Watches and Tornado Watches remain in effect. The FOX Forecast Center and FOX Weather emphasized the combined threats of large hail, tornadoes and rapid runoff in advising residents to monitor local warnings and avoid flooded roads.
