On May 25, 2019, about 1715 eastern daylight time, Southwest Airlines flight 2842, a Boeing 737-8H4, N8697C, encountered turbulence during descent into Jacksonville International Airport (KJAX), Jacksonville, Florida. Of the 128 passengers and crew onboard, one flight attendant sustained serious injuries and one flight attendant sustained minor injuries. The airplane was not damaged. The flight was operating under 14 CFR Part 121 as a regularly scheduled passenger flight from Chicago Midway International Airport (KMDW), Chicago, Illinois, to KJAX. According to the captain, as the flight approached 15,000 feet, he noticed there was a scattered layer of clouds they needed to descend through, and so he elected to provide the 10,000-foot chime to the flight attendants early. As the flight descended through the layer at about 12,000 feet, the airplane encountered moderate turbulence. The seat belt sign was off, and the flight crew had turned off the weather radar about 5 minutes before because they had observed no weather between the airplane and KJAX. According to the flight attendants (FA), the turbulence was encountered shortly after they received the 10,000-foot chime and begun their final walkthrough of the cabin. The two FAs in the aft cabin were thrown into the air and then struck the floor. One of the injured FAs was transferred to a passenger seat for the remainder of the flight. The flight crew was notified of the injury, who requested that paramedics meet the airplane at the gate. After landing, the two aft FAs were transported to the hospital where one was diagnosed with a fractured ankle. Post accident examination of the weather data determined that the turbulence was encountered in the vicinity of the sea breeze front and localized convergence where towering cumulus clouds (cumulus congestus clouds) were depicted on the satellite imagery. There was no lightning detected, pilot reports (PIREPs), or inflight advisories for convection or turbulence current for the area.