The Eastern Pacific hurricane season runs from May 15 through November 30, with peak activity from July through September. It could grow into a Category 4 sometime Friday. It was moving west-northwest at 6 miles per hour (9 kph).
Churning over warm waters that can provide fuel and with relatively little wind shear to disrupt its towering thunderstorms, "there are no obvious reasons why Aletta should cease intensification", the National Hurricane Center said.
Forecasters expect the storm to make a turn toward the northwest over the weekend before a westerly turn Sunday or Monday.
The latest infrared satellite imagery suggests that Aletta has become better organized over the last 6-12 hours and is nearing hurricane status.
The center said the storm was likely to strengthen some more as it moved farther out into the Pacific, but predicted Aletta would begin weakening Saturday.
Aletta was first named a hurricane on Thursday, June 7, which is over two weeks earlier than normal.
The Weather Channel reported the average date when the first named storm forms in the Eastern Pacific Basin is June 10, according to NHS data from 1971 to 2009. "It's happened 3 other times this decade, and a total of 9 times since 1970, per NOAA's database", he tweeted.
Meanwhile, forecasters are also keeping an eye on a broad area of low pressure a few hundred kilometers (miles) southwest of Guatemala.