Tropical Storm Cristobal began picking up speed Monday. Forecasters expected it to pass the Lowcountry on Tuesday far offshore before turning into a hurricane off North Carolina.

The threat of dangerous rip currents will remain high along the beaches through Tuesday evening, along with the threat of shallow coastal flooding at high tides, because the storm is combining with prevailing northeast winds to push water into shore, said meteorologist Doug Berry, with the National Weather Service, Charleston.

High risk means potential rip currents are considered life-threatening. Rips are abrupt, powerful surges out to sea, and tend to occur when shore current, or undertow along the beach, is strong.

The undertow was "a little bit harsh" on Monday, said Evan Willis, of Ocean Surf Shop on Folly Beach. The one-two punch of Cristobal and prevailing winds had already kicked up higher surf.

Waves at 2-3 feet were called for Tuesday at the Washout, Folly Beach's surfing mecca, in a forecast by Magic Seaweed, a surfing website.

"(The surf) is stoking, definitely. It's picking up and getting a lot more power," Willis said. "(Tuesday) is going to be the day, I'm pretty sure. It should be a pretty fun wave."

But Cristobal won't be felt much farther inland. The storm is forecast some 600 miles out to sea, Berry said. Overall the Lowcountry is forecast to be breezy with partly cloudy skies and high temperatures in the mid to upper 80s, he said.

Meanwhile hurricane forecasters have begun eyeing a storm system in the mid-Atlantic that's expected to reach the outer Caribbean islands by the weekend, and likely become a tropical cyclone.

This is the heart of the "Cape Verde period," the late summer weeks that are the height of the Atlantic hurricane year, the time of the worst threat of the storms forming. The threat peaks Sept. 10.

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