After a weekend of staggering strengthening, Hurricane Erin remained a major hurricane Monday on its path skirting away from the United States. And following behind in the Atlantic is another system the National Hurricane Center has given a medium chance of further development.

After losing some power over the weekend, the hurricane strengthened back into a Category 4 storm with maximum sustained winds of 140 mph, according to an 11 a.m. ET advisory from the National Hurricane Center.

Hurricane Erin – an already powerful Category 4 storm in the Atlantic Ocean – is getting stronger and is expected to grow even larger, according to the National Hurricane Center.

Rip currents are the third leading cause of deaths from hurricanes, and they can happen on a sunny day hundreds of miles from the storm.

Tropical Storm Erin formed on Monday and is expected to become a hurricane, and possibly a major hurricane, later this week.

The National Hurricane Center said Tropical Storm Erin is expected to begin strengthening today, Aug. 13 and become a hurricane Friday, Aug. 15, and a strong Category 3 hurricane by Sunday, Aug. 17 as it moves out of an area with dry area and "marginal" sea surface temperatures.

Tropical Storm Erin continues its westward path across the Atlantic, expected to become a hurricane Aug. 15, and a major hurricane by Sunday morning.