The teen was last seen on the water on the north side of the Texas City Dike with family and friends on Saturday morning.
EquuSearch said that Lowery was on a water raft with family and friends when it began to take on water and sink. While others made it out of the water safely and were rescued, Lowery did not resurface.
The Lowery family shared images of Nathan in hopes of helping bring him home.
The teen was last seen wearing a royal blue t-shirt and dark gray shorts, according to EquuSearch.
Anyone with information on Lowery is urged to call the Texas City Police Department at (409) 948-2525 or Texas EquuSearch at (281) 309-9500.