Hurricane Erin has quickly whipped into a catastrophic Category-5 monster storm travelling west across the Atlantic as the East Coast is warned of deadly water conditions.

The storm, sustaining winds of 160mph, is not expected to hit the United States, but heavy rainfall and dangerous water conditions are due to strike. 

Swells from the hurricane are expected to cause 'life-threatening surf and rip currents' on the East Coast, as well as the northern Leeward Islands, the Virgin Islands, Puerto Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas and Bermuda. 

Depending on Erin's size and strength, waves could reach 30 feet or more, meteorologists warned. 

'Families heading to U.S. Atlantic beaches for a late-summer vacation next week need to be extremely cautious when venturing into the surf,' AccuWeather lead hurricane expert Alex DaSilva warned. 

'More than 50 people have lost their lives to rip currents and rough surf at beaches across the country so far this year, without any major hurricane nearby.' 

Erin was upgraded to a Category-5 from a Category-3 storm on Friday evening. A Category-5 storm consists of winds above 157mph. 

'By the middle of next week, Erin is forecast to at least double or triple in size, which will result in rough ocean conditions over the Western Atlantic,' the National Hurricane Center said.

'On the forecast track, the center of Erin is expected to move just north of the northern Leeward Islands, the Virgin Islands, and Puerto Rico over the weekend,' the hurricane center said.  

Outer bands of the storm are expected to produce heavy rainfall until Sunday, with around two to four inches of rainfall. In some areas, around six inches is expected. 

'Locally considerable flash and urban flooding, along with landslides or mudslides, are possible,' according to the NHC.

Hurricane Erin is expected to continue to strengthen, curving toward the East Coast and Bermuda. 

'Fluctuations in intensity are expected for the rest of the weekend,' the hurricane center said. 

AccuWeather warned that the worst-case scenario would see Erin guided directly onshore, 'packing high winds, flooding rain and storm surge flooding.'