PUERTO VALLARTA, Mexico, Aug 29 (Reuters) - Nora, which has now weakened to a tropical storm, killed one boy over the weekend after torrential rains and heavy winds caused a building the popular resort town Puerto Vallarta to partially collapse.

Nora was about 105 miles (165 kilometers) north-west of Mazatlan on Sunday evening and moving north-north west at 12 miles per hour (19 km per hour), the National Hurricane Center (NHC) said https://www.nhc.noaa.gov/text/refresh/MIATCPEP4+shtml/292051.shtml. It was blowing at 60 mph (95 kph) with higher gusts.

In Puerto Vallarta, a river burst, destroying a bridge, flooding roads and bringing a building to collapse, a Reuters witness said.

Earlier, Nora was a Category 1 hurricane, the lowest rating on a five-step scale.

The dead body of a minor was recovered from a partially collapsed hotel, Jalisco Governor Enrique Alfaro said on Twitter. It was not immediately clear whether the second person that had also been missing, a woman, has been located.

"This tragedy was caused by the partial collapse of a hotel in downtown Puerto Vallarta, due to the overflow of the Cuale River," Alfaro wrote. "To his family, who came to our port from Spain 7 years ago, and to his loved ones, all our support and our deepest condolences. R.I.P."

Elsewhere, local media showed pictures of flooding, felled trees, damaged roads and power lines across several states.

The Miami-based NHC expected Nora to continue moving north-northwest on Sunday in its latest advisory and then move slower northwest through Tuesday.

"Gradual weakening is forecast during the couple of days as the center moves roughly parallel to the coast of Mexico," the NHC said. "However, rapid weakening will likely occur if the center moves inland sooner than forecast."

Nora will likely produce additional heavy rainfall along the west coast of Mexico from the states of Jalisco to Sonora through late week, the NHC said. It could also produce life-threatening flash flooding and mud slides, as well as storm surge and large waves.

Last week, Hurricane Grace killed eight people after it hit Veracruz.

(Reporting by Alfonso Lepe in Puerto Vallarta; Additional reporting by Miguel Angel Gutierrez and Stefanie Eschenbacher in Mexico City; Editing by Bill Berkrot and Lisa Shumaker)