It is expected to continue moving northwest today and tonight with a drop in forward speed.
The second Eastern North Pacific hurricane of the season is whipping up 120 miles per hour winds but moving at a glacial pace of about 7 miles per hour.
Hurricane Bud, the second official hurricane in the eastern Pacific Ocean, upgraded to a Category 3 storm on Monday, June 11.
The hurricane is moving north-west at about 10mph - a course it is expected to take until mid-week, the NHC said. Forecasters said the storm could strengthen a bit more before a slow weakening trend started Tuesday.
In terms of rainfall, Bud is predicted to drench southwestern Mexico with three to six inches, with some areas seeing as much as 10 inches.
The rain could cause life-threatening flash floods and mudslides, forecasters said.
A tropical storm watch is in effect from Manzanillo to Cabo Correintes.
The system has a 20 percent chance of tropical development over the next five days, the Hurricane Center reported in its 7 p.m. update. Aletta surged from a tropical storm to a Category 4 hurricane late last week over the span of just 24 hours.
Both Alberto and this system popped in the southern Caribbean, where warm waters early in the season can help fuel tropical cyclones while waters remain too cool farther east in the Atlantic.
A graphic provided by the National Hurricane Center shows the location of Cat 3 Hurricane Bud. It was about 600 miles (965 kilometres) southwest of the southern tip of Baja California.