Porky pies. Re-read AIM/FAR 7-1-27. A "severe downdraft" below the level of an average deck isn't supported by current knowledge of weather. The downward force starts to transition to horizontal below 1000'-3000'. It would be nonexistent below 100'
You'll have to find some other bogeyman. Like maybe zeroing out the airspeed from a wind vector changing to a tailwind, and some subsequent vortex ring condition.
Takes nothing away from the pilots for getting it up to the deck through. And after reading about one case after another where the aircraft ditched without inflating floats, its good to see they remembered where the float button was.
Or.... maybe not, and another porky pie or two. Looking at the photo it looks like the aircraft was equipped with auto-inflate sensors on the belly. Maybe they dipped it in the ocean long enough for the floats to inflate after all, despite what the pilots and the Air Log announcement said. A Gus (Grissom) moment.