If you are planning to do anything outdoors Saturday, take an umbrella.

We're definitely going to have thunderstorms, and some may be severe.

Tornadoes are possible along the coast, so stay in touch with weather updates on a smartphone, the Web or radio and TV.

The storm front that will move eastward through the state Saturday began late Thursday in Oklahoma and has slowly marched across the South, leaving death and destruction in its wake.

Many of the storms in the frontal system have been supercells, especially dangerous storms that can produce tornadoes.

"Sometimes supercells can travel across many counties," said Pete Mohlin, a meteorologist with the National Weather Service office in Charleston. "They can be long-track tornadoes that stay down for a while."

Mohlin said the highest probability of severe storms is between 1 and 7 p.m. Storms are likely to start hitting Dorchester and Berkeley counties around 1-2 p.m. and move into Charleston and the coast by 3 or 4 p.m., he said.

Though the risk for severe weather is high for everyone along the coast, there is a greater risk for the tri-county region, Mohlin said.

Several local events were postponed because of the forecast, but most will go on as planned, rain or shine:

--Folly Beach officials postponed a 5K Fun Run and street festival that were scheduled for Saturday as part of the Sun and Sand Festival. Saturday's events were moved to April 30, but the events planned for Sunday will go on, including the annual Sand Castle Competition, Surfrider Foundation Surfing Contest and Landsharks Concert. Those activities are to take place on the beach in front of the Tides Hotel.

--Goose Creek's "Symphony Under the Stars" concert that was set for Saturday has been postponed due to the threat of rain. The concert is rescheduled for 7 p.m. April 23 on the grounds of the Marguerite H. Brown Municipal Center, the city announced Friday.

--North Charleston's Earth Day Festival was rescheduled for 11 a.m.-3 p.m. April 30 at Park Circle.

--Officials with the Charleston County Park and Recreation Commission will be monitoring the weather at Saturday's East Coast Canoe and Kayak Festival, and they'll get all the kayakers out of the water if the weather becomes dangerous, a parks spokeswoman said. The event is being held at James Island County Park.

--Also on James Island, the grand opening of the Seashore Farmer's Lodge Museum and Cultural Center on Sol Legare Road will not be postponed. An organizer said there is an indoor area at the site.