Tropical Storm Debby, in the Gulf of Mexico Sunday afternoon and headed toward the Big Bend area of Florida, is forecast to impact parts of South Carolina and North Carolina this week. Alerts have been issued for the storm that could bring potentially historic rainfall, rough surf and flooding to these regions.

At 2 p.m. Sunday, the National Hurricane Center issued an advisory for Tropical Storm Debby, noting that it is expected to strengthen into a hurricane before making landfall Monday morning. Debby is expected to move slowly across northern Florida and into southern Georgia before moving into the Atlantic Ocean and up the coast.

The cone that shows the storm’s probable path includes much of S.C. However, many variables remain, including the strength of the still-developing storm and its exact eventual path.

Track Tropical Storm Debby

Track Debby: South Carolina Storm Tracker and Model Mixer

What can we expect in South Carolina?

The Hurricane Center’s forecast shows the center of the storm reaching South Carolina by about 8 p.m. Tuesday. But effects like heavy rain could start as early as Monday night.

Rainfall along the coast is expected to be the main concern. The S.C. coast from the southern part of the state past the Charleston area could see 16-20 inches of rain, with local amounts of up to 30 inches. That will likely result in “considerable” flash and urban flooding, and some river flooding is possible, the Hurricane Center said.

“Heavy rainfall will likely result in considerable flooding impacts from the Florida Big Bend region through southeast Georgia and the Coastal Plain of the Carolinas through Friday,” the Hurricane Center said. “Potentially historic heavy rainfall across southeast Georgia and South Carolina through Friday morning may result in areas of catastrophic flooding. Significant river flooding is also expected.”

The likelihood of storm surges creates a life-threatening situation, the Hurricane Center said. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials.

Rain of about 1-4 inches is forecast for parts of the Upstate.

What watches and warnings are in effect in South Carolina?

A flood watch is in effect from 2 a.m. Monday through Friday morning for southeast South Carolina, including Allendale, Beaufort, Charleston, Coastal Colleton, Coastal Jasper, Dorchester, Hampton, Inland Berkeley, Inland Colleton, Inland Jasper and Tidal Berkeley.

A tropical storm watch is in effect for Charleston, McClellanville and Edisto Island. The forecast calls for winds of 20-30 mph with gusts to 40 mph.

A storm surge watch is in effect beginning Monday afternoon for Charleston, McClellanville and Edisto Island, with a potential of 2-4 feet above ground.

What other watches and warnings are in effect?

As of Sunday afternoon the depression was about 125 miles west-southwest of Tampa, Florida.

• A hurricane warning is in effect for Florida coast from the Suwannee River to the Ochlockonee River.
• A hurricane watch is in effect for the Florida coast west of the Ochlockonee River to Indian Pass * Florida coast south of the Suwannee River to Yankeetown.
• A tropical storm warning is in effect for the Dry Tortugas, the Florida coast south of the Suwannee River to East Cape Sable and the Florida coast west of the Ochlockonee River to Indian Pass.
• A tropical storm watch is in effect for the Florida coast west of Indian Pass to Mexico Beach, and the Georgia and South Carolina coast from the Mouth of the St. Mary’s River to South Santee River South Carolina.
• A storm surge warning is in effect for the Florida coast from the middle of Longboat Key northward to Indian Pass including Tampa Bay.
• A storm surge watch is in effect for the Florida coast from Bonita Beach northward to the middle of Longboat Key, including Charlotte Harbor, and thr Georgia and South Carolina coast from the Mouth of the St. Mary’s River to South Santee River South Carolina.

More: When is first day of fall? SC’s weather forecast by Old Farmer’s Almanac; is it accurate?

More: Heat wave continues, cooling stations open in Spartanburg County. What about Greenville?

Where is Tropical Storm Debby?

Track it: South Carolina Storm Tracker and Model Mixer

Conditions at 2 p.m. Aug. 4:

• Location: 125 miles west-southwest of Tampa, Florida.
• Maximum sustained winds: 65 mph.
• Movement: North-northwest at 13 mph.

More: Heat advisory in effect for Greenville, Spartanburg and Anderson, precautions to stay cool

Are you prepared for a hurricane?

Hurricane season runs from June 1 to Nov. 30. Even if this system won’t pose a threat to the Upstate, it’s never too early to be prepared.

Iris Seaton, Carolinas Connect, and Cheryl McCloud, USA TODAY NETWORK – Florida, contributed.

Todd Runkle is the Carolinas Connect editor and also a content coach for the Asheville Citizen Times, part of the USA TODAY Network. Reach him at trunkle@gannett.com.