The U.S. National Hurricane Center says two tropical storms have gathered strength off Mexico’s Pacific coast Monday, with one forecast to become a hurricane later in the day.

Barbara was a tropical storm in the North Pacific Ocean Sunday morning Mountain time, the National Hurricane Center said in its latest advisory. The tropical storm had sustained wind speeds of 60 miles per hour.

National Hurricane Center forecasters on June 8 said tropical activity in the Atlantic, Caribbean or Gulf of America is unlikely for now.