A319 captain reported temporary loss of aircraft control due to severe turbulence.

Narrative:

Approximately 70 miles south of tij; I turned on the seatbelt sign and advised the flight attendants to take their jump seats. The wind direction and speed were becoming erratic and swinging approximately 80 degrees in short periods of time; so I was getting indications of some weird met conditions. Which led me to believe we could be encountering some turbulence. Approximately 50 miles south; we encountered some light turbulence. At 40 miles; the turbulence increased rapidly to moderate and severe. The aircraft was manually flown to more precisely limit of G and allow for aircraft to fluctuate in altitude to limit hurting the airframe. The airspeed was fluctuating rapidly as well as the wind speed and direction. ATC immediately gave us our requested altitude of 260 which allowed for further performance deviations. The aircraft was struck with some lateral G and rolling left and right. Flight controls were responsive however; the met condition was unsettling during control inputs. Eventually; the turbulence subsided below FL320 and became light. Smooth below FL300.

Original NASA ASRS Text

Title: A319 Captain reported temporary loss of aircraft control due to severe turbulence.

Narrative: Approximately 70 miles south of TIJ; I turned ON the seatbelt sign and advised the flight attendants to take their jump seats. The wind direction and speed were becoming erratic and swinging approximately 80 degrees in short periods of time; so I was getting indications of some weird MET conditions. Which led me to believe we could be encountering some turbulence. Approximately 50 miles south; we encountered some light turbulence. At 40 miles; the turbulence increased rapidly to moderate and severe. The aircraft was manually flown to more precisely limit of G and allow for aircraft to fluctuate in altitude to limit hurting the airframe. The airspeed was fluctuating rapidly as well as the wind speed and direction. ATC immediately gave us our requested altitude of 260 which allowed for further performance deviations. The aircraft was struck with some lateral G and rolling left and right. Flight controls were responsive however; the MET condition was unsettling during control inputs. Eventually; the turbulence subsided below FL320 and became light. Smooth below FL300.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1607148
Time
Date	201901
Local Time Of Day	1201-1800
Place
Locale Reference	MMFR.ARTCC
State Reference	FO
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	A319
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 174.42 Flight Crew Total 6354.35 Flight Crew Type 1348.85
Events
Anomaly	Inflight Event / Encounter Weather / Turbulence Inflight Event / Encounter Loss Of Aircraft Control