By the following day, it had strengthened into a hurricane.
The depression moved west and strengthened into a storm the same day.
We were dressed, and the dawn light had strengthened into day.
It strengthened into a tropical storm soon after and head to the north.
The storm strengthened into a hurricane, though, late on September 11.
Later that day, the system strengthened into a tropical storm.
Three and a half days later, it strengthened into a tropical storm.
The next day, it rapidly strengthened into a hurricane and turned north.
It strengthened into a storm June 19 and a hurricane the next day.
By the morning of June 21, the system had strengthened into a tropical storm.