As the Lowcountry's weather turned tranquil Monday morning, forecasters continued to warn beachgoers to stay out of the ocean because of life-threatening rip currents.

It's the area's most significant weather phenomenon to look out for this week, according to the National Weather Service station for the Charleston area.

The rip currents were affecting the southern South Carolina and northern Georgia coastlines, according to a Weather Service statement.

"No one should enter the surf," the forecasters warned in the statement. A small craft advisory is in effect. The threat comes as Tropical Storm Cristobal spins just west of the Bahamas.

The storm, with sustained winds of 50 mph, was moving northward at 3 mph, according to the National Hurricane Center in Miami. It was expected to pick up speed and curve northeastward, far away from the U.S. mainland, and become a hurricane by midweek west of Bermuda.

All that activity offshore comes after a record high temperature of 99 degrees in Charleston and as the area experiences a brief fall-like respite from the hot weather.

The high temperatures this week are expected to creep back up toward 90 degrees, but forecasters anticipate little when it comes to rain.

They predicted only a 20 percent chance of rain Monday and Tuesday, but that chance will disappear, only to return again for the weekend.

Here is the complete forecast:

Monday: Sunny. Highs in the mid 80s. Northeast winds 15 to 20 mph with gusts up to 30 mph.

Monday night: Partly cloudy in the evening, then mostly cloudy with isolated showers after midnight. Lows around 70. Northeast winds 15 to 20 mph with gusts up to 30 mph. Chance of rain 20 percent.

Tuesday: Mostly sunny. A slight chance of showers in the morning. Highs in the upper 80s. Northeast winds 10 to 15 mph with gusts up to 25 mph. Chance of rain 20 percent.

Tuesday night: Partly cloudy. Lows in the upper 60s, except in the lower 70s near the coast. Northeast winds 10 to 15 mph.

Wednesday Sunny. Highs in the upper 80s. North winds 5 to 10 mph, becoming northeast in the afternoon.

Wednesday night: Mostly clear. Lows in the lower 70s.

Thursday: Mostly sunny. Highs around 90.

Thursday night: Partly cloudy. Lows in the lower 70s.

Friday: Mostly sunny. Highs around 90.

Friday night: Partly cloudy. Lows in the lower 70s.

Saturday: Partly sunny with a slight chance of showers and thunderstorms. Highs around 90. Chance of rain 20 percent.

Saturday night: Mostly cloudy with a slight chance of showers and thunderstorms. Lows in the mid-70s. Chance of rain 20 percent.

Sunday: Partly sunny with a chance of showers and thunderstorms. Highs in the lower 90s. Chance of rain 30 percent.

Reach Andrew Knapp at 937-5414 or twitter.com/offlede.