Hurricane Humberto showed rapid intensification and became a Category 5 storm at the 5 p.m. Saturday advisory from the National Hurricane Center. Humberto is now a Category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale.

Hurricane Imelda is not expected to make landfall in the U.S., but could still affect the East Coast. Here's the local impacts.

Swells and high surf from both Tropical Storm Imelda and Hurricane Humberto are expected to bring dangerous marine conditions and rip currents along much of Florida and the East Coast of the United States during the next several days. ➤ Weather alerts via text: Sign up to get updates about current storms and weather events by location

Hurricane Humberto's swells will probably cause "life-threatening surf and rip current conditions," the National Hurricane Center warned.

The entire Treasure Coast is expected to see large breaking waves of 4-8 feet, which means dangerous swimming and surfing conditions and localized beach erosion, meteorologists said. Sea turtle observers were out Sept. 30 looking at nests, so the county will know how many nests were disturbed by Imelda, she said.

The National Hurricane Center's 11 p.m. Monday update reported that Category 4 Hurricane Humberto is in the Atlantic Ocean, 295 miles southwest of Bermuda. Packing maximum sustained winds of 140 mph, the hurricane is tracking north-northwest at 13 mph.

A combination of weather factors and geography helped make it one of the most brutal storms in the modern history of hurricanes.