Vicksburg and Warren County were battening down hatches today in anticipation of Isaac dumping up to 10 inches of rain on the area Wednesday and Thursday.

Rains were expected to begin today and continue across Warren County for up to three more days, officials said.

Isaac this morning was on the verge of ballooning into a hurricane and expected to flood the coasts of Mississippi, Louisiana, Alabama and the Florida Panhandle. Winds must be 74 mph for a storm system to be declared a hurricane.

Warren County Emergency Manager John Elfer said county and city emergency officials have been meeting for more than a week to prepare for the storm.

“We have a plan and we’re ready for whatever the storm brings,” Elfer said.

Superintendent Elizabeth Swinford said at mid-morning a decision had not been made on whether classes would be in session throughout the week, but she expected to make that call later today. Information will be available at www.vicksburgpost.com.

The signs of anticipation and anxiety began to show across Vicksburg and Warren County Monday and continued this morning.

Vehicles lined up at gas stations as drivers filled up or topped off tanks; hotels and motels across the city were reporting full bookings with many of the rooms rented by evacuees from the Mississippi Gulf Coast and South Louisiana.

About 4,500 extra Entergy workers from outside Mississippi were to arrive in Vicksburg today and work on restoring power as the need arises, Entergy spokesman Don Arnold said Monday.

Entergy told officials Monday that 30 mph sustained winds would cut power to 2,000 customers in Warren County. If winds exceed 60 mph, then 5,000 to 10,000 locals could be without power for five to seven days.

If power goes out, it might mean traffic lights won’t work properly. On Monday, Vicksburg police stressed motorists treat intersections without a working signal as if they were four-way stop intersections.

The National Weather Service was predicting rainfall of up to 10 inches in Warren County between noon Wednesday and Thursday evening. The last time Vicksburg experienced 10 inches of rain was on April 6, 2003, when a weather system dumped 10.25 inches in hours in a system that also produced hail and winds recorded as high as 70 mph.

The 2003 storm caused flooding in Hamilton Heights Subdivision and flooding at the city’s wastewater treatment plant, where electricity was knocked out.

The high winds destroyed a 5,000-square-foot portion of the roof of the first-grade wing at Redwood Elementary School and damaged Warren Central High School, forcing a new roof over a gymnasium.

On Monday, the City of Vicksburg declared a state of emergency, chiefly as a first step to receive federal aid to reimburse cleanup costs and overtime paid in city departments. Warren County supervisors held off a similar declaration until later today to wait out more specifics on the storm’s path.

“It allows us as a municipal government to start accounting for our natural disaster expenditures,” Mayor Paul Winfield said at a called meeting Monday.

Across the United States, Isaac was being compared with Hurricane Katrina, which devastated the Mississippi Gulf Coast and New Orleans seven years ago, on Aug. 29, 2005.

After Katrina, some homes and businesses in Warren County were without electricity for up to two weeks.

In Louisiana and on the Mississippi Gulf Coast, shelters were opened late Monday and today in anticipation of Isaac, which was forecast to make landfall late tonight or early Wednesday.

The American Red Cross opened six shelters in Mississippi on Monday, in Forrest, Hancock, Jackson, Harrison, Hinds and Marion counties, according to the organization’s Mississippi Region office in Jackson. The closest to Vicksburg is in Jackson, at the Mississippi Coliseum.

During Monday’s briefing with city department heads, Winfield mentioned the Vicksburg Auditorium as a possible shelter. The Red Cross makes the call on where its personnel staff a shelter.

Forecasters warned that Isaac was a large storm whose effects could reach out 200 miles from its center. Water may be worse than wind because the storm could push walls of water while dumping rain to flood the low-lying coast in Louisiana, Mississippi, Alabama and the Florida Panhandle.

Rain from the storm could total up to 14 inches, with some isolated areas getting as much as 20 inches, along the coast from southeast Louisiana to the extreme western end of the Florida Panhandle.

All 12 casinos were ordered shut down on the Mississippi Gulf Coast today.

So far, the storm’s main damage in the United States has been political: Republicans cut one day off their presidential nominating convention in Tampa in case the storm struck there, though in the end it bypassed the bayside city. Isaac is also testing elected officials along the Gulf from governors on down to show they’re prepared for an emergency response.

In New Orleans, the U.S. Army Corps of Engineers said the levees are improved and ready to hold up after $14 billion in work since Katrina crashed walls around the city and left it a giant nasty swamp of mud and filth.

New Orleans Mayor Mitch Landrieu did not activate a mandatory evacuation Monday. Instead, officials urged residents to hunker down and make do with the supplies they had.

Anxiety was high, especially in the Lower 9th Ward, wiped out by Katrina.

“I don’t really trust the levees,” said Robert Washington, who planned to evacuate along with his wife and five children. “I don’t want to take that chance. I saw how it looked after Katrina back here.”

One question haunting coast areas is how much oil left over from the Gulf oil spill in 2010 might wind up on the beaches because of Isaac. Experts believe large tar mats lie submerged just off the coast, but no one knows where they are or how many might be in the Gulf.

The Associated Press contributed to this report.