(CNN)It's all "blue sky and calmness," Mayor Frank "Boo" Grizzaffi tells CNN less than a day before Tropical Storm Barry is due to arrive in Morgan City, Louisiana.
A Louisiana mayor fears torrential rain, not a tidal surge, will overwhelm his city's drainage pumping system
The year's first tropical system is due to land Saturday west of the city of 12,000 people, ushering in a 3 to 6 foot tidal surge on the already-high Atchafalaya River. A flood warning has been issued by the National Hurricane Center.
Hurricane force wind gusts are expected to peak around 4 a.m. Saturday in Morgan City, about 70 miles southwest of New Orleans.
But it's the very heavy rain, which could hang around awhile, that's worrying Grizzaffi.
"We're buckled down," says the mayor, who is concerned that his city's drainage pump system will be overcome not by the tidal surge but by torrential rain -- 20 to 30 inches predicted this weekend.
As in other towns in south Louisiana, the entire city's drainage system relies on pumps to move water off the streets, so a downpour, if it is swift and hard, could spell trouble.
"We can handle the first 5 inches, but after that, we can pump 1 inch per hour. If we get rain greater than that, it will exceed our capacity to pump it out," Grizzaffi notes.
As of Friday morning, additional pumps from the state are on their way, but the extra pumping power may still not provide enough capacity to keep up with the deluge.
Meantime, other preparations are happening.
"By noon, we'll have the city shuttered down," Grizzaffi says. That includes preparing to close the floodgates that stay open till the last minute as major oil companies that operate on nearby waterways shut down.
Evacuations are voluntary and apply only to people living near Morgan City and south of the intracoastal waterway.
For city workers, it's "all hands on deck," Grizzaffi explains. At some point, non-essential employees will go home to prepare for the coming storm while a 24-hour crew will "man the phones" over the weekend at City Hall.
Among the city employees still at their posts Friday is Geraldine Besse.
"It's a nice day, the sun's out. It's like a fall day with the weather breezy, cooler than it normally is," the library supervisor tells CNN Friday. She rushes to get off the phone, what with all the children expected as the library ends a summer program.
She knows the Atchafalaya is high, but it's a "normal thing" in long rainy periods, she tells CNN. "The gates have been closed because we've had high water," she says.
The library is normally closed on Saturdays and Sundays, so Besse has no immediate concerns about Barry. Only the children are on her mind.
Speaking a day earlier in Morgan City, which bears the motto "Right in the Middle of Everywhere," Gov. John Bel Edwards pointed to the hard work of partners at every level -- local, state and federal -- in preparing to face Barry.
"This is a very significant severe weather event, and the National Weather Service, they're using terms like 'life-threatening floods,'" said Edwards, who's already declared a statewide state of emergency and gotten a federal emergency declaration.
The storm could "just as easily arrive as a Category 2 as a Category 1" storm, Edwards said. "We believe there will be widespread flooding, not just here ... but across a huge swath of the state."
Still, he remains optimistic "not because I trust Mother Nature," he said, but because he trusts his partners, including 3,000 National Guard members who are "the best in the country" with "the most experience."
Grizzaffi wasn't mayor in August 1992 when Hurricane Andrew hit Morgan City. But he remembers how that Category 3 storm just "flattened us out," he says. "Everything is self-supportive in the city, so we had to put it all back together."
Knowing a "big rain" is headed his way first put Grizzaffi this week into a kind of paralysis. "Three days ago," he says, "I wouldn't get out of my recliner with the forecast."
But today, he says, he feels ready: "The doom and gloom has shifted."