Those flying in/out of airports and airspace in southern California, central and western Arizona, and extreme southern Nevada will encounter severe turbulence, prompting the National Weather Service’s Aviation Weather Center to issue an alert to the area, warning pilots, crew, and passengers of the rough air.
The area under the alert includes Los Angeles area airports such as LAX, Long Beach, Ontario, and John Wayne Orange County. San Diego Airport in southern California and Phoenix Airport in Arizona are also within the alert area. According to the National Weather Service, “SIGMET VICTOR 2 has been issued for Severe Turbulence until 0041Z 21 Jan 2020.”
The airspace impacted is used by many domestic and international routes. LAX is a major international airport with flights across the Pacific to Australia and Asia. Phoenix is a significant hub for American Airlines. Flights departing to/from Hawaii in southern California would also be impacted.
Aircraft encounter turbulence when the air around them experiences chaotic changes in pressure and flow velocity. While air around thunderstorms can be quite turbulent, turbulence can also occur on clear weather days if wind and pressure are just right.