NEW ORLEANS — Overcast skies and the threat of rain couldn’t dampen the revelry of Mardi Gras as parades took to the streets early Tuesday, showering merrymaking crowds with trinkets of all descriptions.

Parading began around dawn, led by clarinetist Pete Fountain and his Half-Fast Marching Club. The Zulu krewe and the parade of Rex, King of Carnival, were to wind their way down stately St. Charles Avenue to the business district during the morning.

Parade-goers lined up despite the threat of inclement weather. Some families camped out overnight to stake out choice spots to view parades.

The French Quarter stirred to life and later in the day was expected to become the center of the celebration’s raunchier side.

The wet streets that greeted revelers who braved rainy forecasts threatening to wash out Mardi Gras, New Orleans’ biggest free show.

Freddie Zeigler, a National Weather Service meteorologist in Slidell, La., said there’s an 80 percent chance of rain Tuesday. Fog blanketed the riverfront and business district in the early morning.

Still, lulls are predicted throughout the day and no parades had been canceled. The Zulu parade began on time at 8 a.m.

“It’s going to be dicey though for parades, but it all depends on how fast that warm front moves to the north,” Zeigler said.

Following the Zulu and Rex parades would be hundreds of trucks decorated by families and social groups.

Fountain’s Half-Fast Marching Club stepped off from a staging point in the Garden District just after dawn. Others with colorful names such as the Jefferson City Buzzards would follow, tossing beads to the crowds along stately St. Charles Avenue and winding their way into the city’s business district.

Fountain and his clubmates were clad in garish red suits and feathered hats as they got ready to march in the Garden District.

Fountain no longer walks the route, which will take him to the French Quarter, but rides a truck-towed trolley. As he boarded, parade-goers snapped photos with camera phones.

Fountain wasn’t worried about the rain forecast.

“This is my life,” he said, referring to his 63rd parade with the group he founded. “We’re going to make it before it rains.”

Bob Johnson sipped on a screwdriver as he prepared to march with Fountain. “This is a half-healthy drink,” he joked.

Johnson has done parades on floats and has been with Fountain’s street marchers for six years. “It’s a whole different perspective than riding a float. You can get right up to people,” he said.

In the French Quarter, where the revelry almost didn’t stop overnight, crowds were expected to cruise down Bourbon Street, pleading for beads from revelers on balconies before heading to Canal Street for the parades.

Traditionally, the French Quarter is the scene of Mardi Gras’ most ribald activities, while the streetcar line along St. Charles is given over to family groups who set for a day of barbecues and parade watching.

On the uptown parade routes, families carried on generations-old traditions of camping out overnight in tents to catch the earliest action. Many hoped to catch one of the colorfully decorated coconuts handed out by grass-skirt-clad riders on the Zulu floats.

Bryan Clark, 42, said it would take more than the threat of rain to break his family’s tradition of camping near the place where the Zulu parade turns onto St. Charles Avenue. “We stay here rain sleet or snow,” he said.

The New Orleans native said his parents hooked him on the Mardi Gras ritual and now he does it with his wife and children. “There is no other place in America you can do this,” he said.

Parading was planned across south Louisiana and the Gulf Coast. In Louisiana’s Cajun parishes, the tradition of the Courir du Mardi Gras was set to start after dawn, as groups of maskers on horseback would ride from community to community making merry.

Rain or shine, it was parade-goers last chance during the Carnival season, which ends with the stroke of midnight Tuesday night. After that, the solemn season of Lent replaces the revelry until Easter.

“We’re going to get here extremely early,” said Carly Gerhard, who drove with a friend from Philadelphia to New Orleans over the weekend — through storms that spawned tornadoes along the way — for her first Mardi Gras experience.

Gerhard said her most memorable experience so far has been the French Quarter.

“We’re looking forward to the parades. We’re looking forward to it all,” she said.

Frank Warford, of Riverdale, Ga., was holding an umbrella Monday as he walked Bourbon Street. He said he was ready to party through the rain.

“This is a party city. Everybody’s partying and having fun, catching beads like crazy,” said Warford, his neck draped in beads. “If it rains, put a hat on. It’s as simple as that.”

Scattered showers didn’t keep revelers away Monday as thousands flocked to the French Quarter and along the Mississippi River for Lundi Gras festivities.

As local brass bands played on stages set up along the river, Jim and Sheron Rogers, of Bay St. Louis, Miss., beers in hand, said they hadn’t missed a Mardi Gras since 1990, and that come rain or shine they were taking in this one.

“We just love it,” Sheron Rogers said. “The people, the music. It’s just a beautiful, fun city.”

Many said they weren’t going to let the rain or weekend shooting on Bourbon Street wreck the party.

“You can’t let the threat keep you from having a good time,” Jim Rogers said.

Deron Bridgewater, 23, of Marrero, La., faces four counts of attempted first-degree murder for the weekend’s quadruple shooting during the final weekend of revelry that culminates with Mardi Gras.

Bridgewater surrendered Monday after seeing his photograph on a television newscast Sunday night, New Orleans police spokesman Frank B. Robertson III said. Police have issued an arrest warrant for a second suspect in the shooting and authorities sought a third person who is believed to have critical information regarding the shooting, Robertson said.