It grew from a Tropical Storm to a Category 3 hurricane within 24 hours.
The center of the storm was located about 455 miles west-southwest of Manzanillo, Mexico.
"The remarkable intensification of Aletta has continued through this morning", the National Hurricane Center wrote in its 11 a.m. advisory. Meteorologist Travis Herzog says June is typically a quiet month in the Atlantic with 90% of all hurricane activity normally occurring after August 10th. It predicts the storm's intensity to peak late Friday, with maximum winds of 145 miles per hour, just about 10 miles per hour shy of Category 5 levels.
Forecasters said the hurricane may gain more intensity before a combination of increased wind shear and decreasing ocean heat will cause Aletta to break down. Aletta should strengthen over the next couple days before weakening back to a tropical storm midday Sunday and a tropical depression midday Tuesday.
Kwiatkowski back in yellow as Sky dominate Dauphine TTT
The 181km fourth stage on Thursday will see riders head into the mountains between Chazey-sur-Ain and Lans-en-Vercors. Like Mitchelton-Scott, they have a solid time trial line-up with Michal Kwiatkowski, Geraint Thomas and Gianni Moscon.
Aletta was first named a hurricane on Thursday, June 7, which is over two weeks earlier than normal.
Forecasters are also keeping an eye on another area of low pressure to the east of Aletta.
Forecasters said Aletta is now a Category 3 hurricane.
An average Eastern Pacific hurricane season produces 15 to 16 named storms, with eight to nine becoming hurricanes and four becoming major hurricanes.