It's an unusual time of year for tornado warnings, but given the warm temperatures in the southeastern U.S., forecasters are warning residents to beware of strong wind gusts overnight and into Wednesday. 

The National Weather Service says the following areas are most at risk: Much of Arkansas, southern Illinois, extreme southwestern Indiana, western Kentucky, northern Louisiana, parts of southern Missouri, parts of northern Mississippi, extreme southeastern Oklahoma, western Tennessee, extreme northeastern Texas. 

Read more from weather.com

Additionally, The Weather Channel gave a 50 percent chance of seeing a tornado in Alabama.

Temperatures are about 22 to 26 degrees above average, according to weather.com, and damaging wind gusts of 70 to 80 mph are predicted south from Biloxi, Miss. east to the Virginia. On the periphery of those wind gusts, isolated, spin-up tornadoes may form.  

The Weather Channel warns that the combination of strong winds -- in some areas up to 150 mph -- could result in straight-line wind damage and prime conditions for tornadoes to form. 

The weather service said the threat for severe thunderstorms will increase through Tuesday night in advance of a strong cold front moving across the central U.S. 

State and local emergency managers are on watch, the weather service said.

Michael Heiman / Getty Images file

The corner of 34th Street and 1st Street in Manhattan floods during rains from Hurricane Sandy, Oct. 29, 2012 in New York City.

Some 35,000 buildings and homes have been added to flood zones in parts of New York City, according to preliminary maps released Monday by the Federal Emergency Management Agency. More of these maps will be released in late February for Manhattan and other parts of city where the data is still being analyzed. 

The numbers emerged after the release earlier in the day of FEMA’s advisory flood maps for parts of the city, increasing the areas falling into 100-year flood zones or areas with the potential for destructive high speed waves along coastlines, said agency spokesman Dan Watson. More maps will be released for other parts of the city, including Manhattan, in late February, he said. 

The official maps will be released in the summer, but the preliminary ones for hard-hit areas like Staten Island and Queens are intended to give those who are rebuilding a head start. Sandy struck Oct. 29, leaving about 20,000 residential buildings in the city with some damage or disruption to their utilities.

“It can inform building back stronger and smarter with the recovery,” Watson said. “And honestly it will also help save lives and property in the future … because we’ve seen areas where folks have elevated or used other forms of mitigation and … they got wet but there wasn’t as much damage as a result of it.” 

The maps reflect base flood elevations and will likely increase insurance rates for those who are newly included in the flood-prone zones. Those who are now in the “A Zones” -- or 100-year flood zones, where a flooding event has a one percent probability of occurring in any given year -- and who have a federally-backed mortgage will be required to get flood insurance once the flood maps are formally adopted, Watson said.

Some property owners may also have to elevate their buildings or homes, likely setting ground floors ground floors 3 to 6 feet higher than zoning rules previously required, according to The Associated Press. The maps have to be adopted by communities, which can appeal parts of them, Watson said.

Congress has already passed $9.7 billion in additional borrowing authority for the National Flood Insurance Program to help pay Sandy claims from homeowners in New York and New Jersey. The Senate on Monday night approved a $50.5 billion emergency spending bill to aid people in New York and New Jersey who are trying to rebuild their homes and businesses.

Hard-hit communities were just beginning to figure out what these initial maps mean for them. In Breezy Point, a private cooperative in the city’s southern Queens Borough heavily damaged by the storm, leaders said they needed to study the maps before offering guidance: “Keep in mind that the DOB (Department of Buildings) and City still need to make decisions regarding building criteria and if it will change.”

Updated at 5 p.m. ET: Heavy rain storms dumping on central and north California Saturday night and Sunday knocked out power to thousands in San Francisco, Sacramento and elsewhere and caused moderate flooding in a number of communities.

The area, which had been saturated by two major weather systems in the last five days, is expected to receive a short reprieve from the rain before another storm comes through on Tuesday evening, The Weather Channel reported.

The inundation has caused a number of mud and rock slides, mostly during the period of heaviest rain, which then moved eastward across Fresno and Merced, Calif.

There were also reports of road flooding during and just after the heaviest rain, but that threat appeared to lessen as the rain moved into regions that haven't had as much recent rain. All flash flood warnings have expired.

The Truckee River, which wends its way from Lake Tahoe in California to Pyramid Lake in Nevada, 120 miles to the northeast, was rising more slowly than expected, and most flood predictions along the way were scaled back.

In Truckee, Calif., the river was expected to cause minor flooding Sunday afternoon and evening and moderate flooding east of Reno near Vista, Nev. as it crests at a predicted 18.7 feet.

The threat of flooding prompted officials in Truckee, a town of about 16,000, to set up an evacuation center. 

Just across the border in Nevada, a state of emergency was declared in Washoe County, including the cities of Reno and Sparks, due to the expected flooding. In Reno, several casinos announced cut-rate rooms to accommodate those displaced, while the City of Sparks opened an evacuation center in a high school.

San Francisco area gets set for third storm system — and flight delays, traffic mess 

Minor flooding was also reported on the Napa River near St. Helena Calif., along the Navarro River near the town of Navarro, and on the Mad River near Arcata. Moderate flooding was still predicted for elsewhere on the Navarro river and parts of the Eel, Russian and Napa rivers.

The Napa River overwhelmed downtown Napa in 2005, flooding or destroying about 1,000 homes and forcing thousands of residents to leave the area.

There, residents worked to fill 700 bags with 10 tons of sand, city official Danny Lerma said. 

Cathleen Allison / AP

Eric Engles, with Carson City Public Works, clears a storm drain in Carson City, Nev, as a heavy, wet storm hits Northern Nevada on Sunday.

"When you see it happen, you always remember, and you say, 'I'm going to be better prepared,'" Lerma told KGO-TV. "And that's what they're doing right now."

Click here for more weather headlines 

The latest storm, which came ashore Saturday night, knocked out power for about 5,000 customers in the Sacramento. It was restored for all but 2,000 customers by 1 p.m. PT. according to the Sacramento Municipal Utility District. Another 6,000 lost power in Santa Rosa, Sonoma County, and 8,000 in San Francisco, according to The Weather Channel.

The Napa River was expected to flood near St. Helena and Napa around noon on Sunday, while the Russian River was expected to flood near Guerneville early Monday morning. 

The Napa River overwhelmed downtown Napa in 2005, flooding or destroying about 1,000 homes and forcing thousands of residents to leave the area.

Holiday cancellations
The weather prompted cancellations of holiday parades and tree lightings in Sparks and Truckee. 

Officials also warned people to be careful along beaches. 

A high surf advisory was issued by the Weather Service, with swells expected to be 14 to 16 feet along the Northern California coast.

In Southern California, high surf was predicted in Los Angeles, Orange and San Diego counties. 

The stormy weather may be behind a crash involving multiple cars on Interstate 280 outside of San Francisco on Saturday morning, as well as the death of a Pacific Gas & Electric worker in West Sacramento who died after his truck crashed into a traffic signal pole during the stormy weather Friday. 

NBC News' Kari Huus and The Associated Press contributed to this report.

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Gerald Herbert / AP

This flood wall and floodgate are along Lakeshore Drive and Lake Pontchartrain in New Orleans, La.

In the busy and under-staffed offices of New Orleans' flood-control leaders, there's an uneasy feeling about what lies ahead.

By the time the next hurricane season starts in June of 2013, the city will take control of much of a revamped protection system of gates, walls and armored levees that the Army Corps of Engineers has spent about $12 billion building. The corps has about $1 billion worth of work left. 

Engineers consider it a Rolls Royce of flood protection — comparable to systems in seaside European cities such as St. Petersburg, Venice, Rotterdam and Amsterdam. Whether the infrastructure can hold is less in question than whether New Orleans can be trusted with the keys. 

The Army Corps estimates it will take $38 million a year to pay for upkeep, maintenance and operational costs after it's turned over to local officials. 

Local flood-control chief Robert Turner said he has questions about where that money will come from. At current funding levels, the region will run out of money to properly operate the high-powered system within a decade unless a new revenue source is found. 

"There's a price to pay for resiliency," the levee engineer said from his office at the Southeast Louisiana Flood Protection Authority-East. "We can't let pieces of this system die away. We can't be parochial about it." 

On Nov. 6, New Orleans voters were faced with one of their first challenges on flood protection when they voted on renewal of a critical levee tax. The tax levy was approved, meaning millions of dollars should be available annually for levee maintenance. 

Bob Bea, a civil engineer at the University of California, said the region must find additional money to keep the system working properly. "If you try to operate it and maintain it on a shoestring, then it won't provide the protection that people deserve." 

Many locals remain uneasy, even though Turner's agency is a welcome replacement for local levee boards that were previously derided. 

"It's scary," said C. Ray Bergeron, owner of Fleur De Lis Car Care, a service station in the Lakeview neighborhood where water rose to rooftops after levees collapsed during Hurricane Katrina in August 2005. Before Katrina, Bergeron said the local levee boards were complacent. "They told everybody everything was fine, 'Oh yeah, it's fine. Let's go have martinis and lunch.'" 

After Katrina, the locally run levee boards that oversaw the area's defenses were vilified, and quickly replaced by the regional levee district run by Turner. 

Congressional investigations found the old Orleans Levee Board more interested in managing a casino license and two marinas than looking after levees. Inspections were ceremonial, millions of dollars were spent on a fountain and overpasses rather than on levee protection. And there was confusion over who was responsible for managing the fragmented levee system, U.S. Senate investigations revealed. 

Still, experts generally agree the old levee board's failings did not cause the levees to collapse during Katrina. Poor levee designs by the corps and the sheer strength of Katrina get the lion's share of the blame. 

Since the Flood Control Act of 1936, the Army Corps has given local or state authorities oversight of water-control projects, whether earthen levees in the Midwest or beach walls in New England. 

Bill Haber / AP

Water is pumped through giant tubes around the floodgate at the London Ave. outflow canal during a test in New Orleans in May 2009.

"That's been the eternal problem with flood-protection systems," said Thomas Wolff, an engineer at Michigan State University. "You build something very good and then give it to local interests who are not as well-funded." 

New Orleans is an unusual case because the area is inheriting the nation's first-of-its-kind urban flood control system. 

"We've given a very expensive system to a place that may not be able to afford it over the long term," said Leonard Shabman, an Arlington, Va.-based water resources expert. Letting the Army Corps run it isn't much of a solution either, he added. "It's not like the corps' budget is flush." 

The nation has spent lavishly on fixing the system in the seven years since Katrina flooded 80 percent of New Orleans and left 1,800 people dead. 

"It is better than what the Dutch have for the types of storms we have," said Carlton Dufrechou, a member of the board of the Lake Pontchartrain Basin Foundation, which monitors local environmental issues. 

Ensuring it remains that way could be tricky. The biggest headaches are several mega-projects with lots of moving parts, all needing constant upkeep. The corps is building them across major waterways that lead into New Orleans. 

Take for instance the 1.8-mile-long, 26-foot-high surge barrier southeast of the French Quarter that blocks water coming up from the Gulf of Mexico across lakes and into the city's canals. Water from this direction doomed the Lower 9th Ward and threatened to flood the French Quarter. Maintaining this giant wall alone will cost $4 million or more a year. 

"You have to get out there and do exercises, do the preventive maintenance, change out equipment over time on a particular schedule," Turner said, enumerating the challenges. "There are a lot of cases where a single thing goes wrong and that can create a failure, a complete failure where you can't close the system." 

There is a mounting list of to-dos. 

Already, lightning has knocked out chunks of wall. Grass hasn't grown well on several new stretches of levee. Louisiana State University grass experts have been called in to help seed them. 

There are recurring problems with vibrations and shuddering on a new floodgate at Bayou Dupre in St. Bernard Parish. The corps has plans to overhaul the structure in the spring before handing it over to local control. And there will be the inevitable sinking of levees and structures, as always happens in south Louisiana's naturally soft soils. Over time, levees will have to be raised. 

Col. Ed Fleming, the New Orleans corps commander, said his outfit will work to ensure the transition to local control is smooth. 

"This happens with corps civil projects all over the country. That's the way it works in Iraq, Afghanistan," he said. "We have authority to build, but we have no authority to do operations and maintenance." 

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John Makely / NBC News

Miatid Amini makes his way with his family onto a truck in Moonachie, N.J., on Tuesday. Frank Mercadante, right, assists.

TETERBORO, N.J., Updated at 3:15 p.m. ET — Residents of four northern New Jersey towns inundated when a levee failed to hold back Sandy's storm surge said Tuesday that they were terrified to see a torrent of water racing through their streets.

"Around 10 p.m. (Monday) water just started rushing down the street ... there was no stopping it," said Stefania Davi, 34, of Little Ferry, one of the four Bergen County boroughs hit by the floodwaters. Two hours later, it burst through the family's garage door. "We're doomed," Davi remembered thinking.

Davi, a mother of three boys, and her husband, Salvatore, were among hundreds of residents of Moonachie, Little Ferry, South Hackensack and Hackensack drying out and trading hugs and tears early Tuesday at the Bergen County Technical High School in Teterboro.

There also were tales of dramatic rescues.

Frank Lofaro, 32, said he jumped on his Jet Ski to help ferry about a dozen of his neighbors in Little Ferry to waiting rescue boats.

"We'll do our own share," he remembered thinking, though he acknowledged he was scared piloting the personal watercraft through the water.

John Makely / NBC News

The flood aftermath in Moonachie, N.J., on Tuesday.

He also used the Jet Ski to take his wife, Angela Valenta, 37, their two children and their 5-year-old dog, Lucky Leo, to the rescue boats.

Valenta said her son, 9-year-old Angelo, was crying during the flooding. "He kept saying, 'Am I going to die?'" she said.

There were conflicting accounts on whether the levee protecting the towns broke or was overtopped. 

The National Weather Service issued a statement Tuesday morning saying that "portions" of the towns were submerged after the levee broke. But Jeanne Baratta, a spokeswoman for Bergen County Executive Kathleen Donovan, said the flooding occurred after the swollen Hackensack River overflowed its banks, Reuters reported.

She told the New Jersey newspaper, The Record that the towns, along with parts of Carlstadt, had been "devastated" by the flood of water. And she said that as many as 1,000 residents had to leave their homes and that people in a trailer park had to climb onto the roofs of their trailers to await rescue, NBCNewYork.com reported.

Among those evacuating residents were members of an extended family from the area with a military-style transport cargo truck. By mid-afternoon, they had ferried an estimated 275 passengers, including a pregnant woman, children and pets, to the shelter and other stops in the truck, which had rubber bats and lights inside from recent duty as a Halloween ride.

During a trip into the flood zone residents waved the truck down as it plowed through several feet of standing water, or simply waved and cheered the crew on.

"People in need, that's what we're all about," said John Mercadante, 47, president of a medical imaging center in Clifton.

One of those they plucked up from their flooded doorstep was Russell Gassler, 56, and his mother, Claire, 80. The younger Gassler, a driver for a paint business, said his street was "bone dry" until the water started "raging" down it.

"It just came, the waves," he said. "I just couldn't believe it."

Little Ferry Mayor Mauro Raguseo, who was greeting fellow residents at the Teterboro shelter, was unable to shed any light on the cause. "All we were told is that it's a levee problem," he said.

Raguseo said that rescues were continuing early Tuesday afternoon.

"I'm just concerned at the moment for the people that are still in their homes," he said.

John Makely / NBC News

Laura Wyer sits with her dog Bailey in the Bergen County Technical School on Tuesdayafter being evacuated from her home in Moonachie, N.J.

Davi and her husband and three boys watched nervously through the night, "just praying and praying" as the floodwater lapped at the threshold of their raised first-floor living quarters.

It never came in, though, before the family was rescued by boat early Tuesday, along with their 2-year-old Cocker Spaniel, Rosie.

Davi, who was able to grab some family photos and computers before climbing into the boat, said she was feeling optimistic that her family would soon be back on its feet despite the ordeal.

"Today's a new day and tomorrow will be another one," she said. "I survived cancer. I can survive a flood."

But Mayor Raguseo said he was among the residents to feel the Sandy's full sting.

"I've lost everything as well,” he said of the home that he moved into six months ago. "It's just devastating." 

Slideshow: Sandy slams into East Coast

Andrew Burton / Getty Images

Superstorm Sandy made landfall Monday evening on a destructive and deadly path across the Northeast.

Launch slideshow

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Eduardo Munoz / Reuters

Tennis fans shelter from the rain while play is suspended at the U.S. Open tennis tournament in New York City on Tuesday.

The remnants of former Hurricane Isaac brought heavy rain and strong winds -- and the risk of localized flash flooding -- to the East Coast overnight and into Tuesday.

New York City can expect up to three inches of rain Tuesday and Wednesday, NBCNewYork.com reported. High humidity will make temperatures feel like the high 80s, it added.

Torrential downpours were forecast for the Northeast and South Atlantic states, while thunderstorms were possible across the Midwest.

The system follows a humid, damp and windy end to the Labor Day weekend in many parts, including Delaware, where strong thunderstorms and winds of up to 60 mph ripped through Kent County, Del., on Monday, damaging homes, according to NBCPhiladelphia.com.

The Weather Channel said the turbulent weather was caused by the merger of the remnant low pressure of Isaac with a frontal boundary across the Midwest.

"That low and that front are still with us, and will be poking into the Northeast by Wednesday," wrote the Weather Channel's Nick Wiltgen. "They'll interact with rich tropical moisture to bring the threat of tropical downpours up and down the eastern seaboard Tuesday and Wednesday."

"These will be the kind of downpours that can put down an inch of rain in less than an hour and reduce visibility to a few hundred feet," he added, "so drivers and air travelers can expect occasional delays. Localized flash flooding is possible."

Around 20 homes in Camden, Del., were damaged during Monday’s storm there.

Those who saw it coming ran into their homes and ducked for cover.

"When we went in, I shut the sliding doors and something hit the house so hard and we just dropped to the floor," Jean Hanacek told NBCPhiladelphia.com. "My whole garage is gone and my two cars are in there."

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Gerald Herbert / AP

Officials intentionally breached a levy Thursday to alleviate trapped floodwater in the community of Braithwaite, La., in the aftermath of Hurricane Isaac.

Updated at 1:24 a.m. ET: Up to 50,000 people in Louisiana's Tangipahoa Parish were ordered to evacuate Thursday when water from Isaac -- which by late afternoon had weakened to a tropical depression -- threatened to overwhelm a dam across the state line in Mississippi.

Bing Maps

The dam at Percy Quin State Park in Mississippi is located at the southern end, seen here with a blue bullet.

By late Thursday, the Percy Quin State Park dam, located about 100 miles north of New Orleans, was no longer an imminent threat, dam safety engineer Dusty Myers said.

Mississippi officials, for their part, said they didn't think the volume of water in the 700-acre lake at Percy Quin State Park near McComb, Miss., would add enough flow to threaten communities downstream.

And Gov. Bobby Jindal said that if the dam were to break, a natural flood plain would prevent communities in Louisiana from being flooded. 

Officials by late Thursday afternoon had started a controlled release from the dam to minimize flooding.

John Moore / Getty Images

A family fleeing the potential dam break waits to enter a shelter in Kentwood, La., on Thursday.

Hundreds were evacuated in darkness overnight while new areas in southern Louisiana flooded as Tropical Storm Isaac crawled north. Its eye was heading toward Arkansas, but its heaviest rain bands were now moving over Mississippi.

"We still have people penned in both (Plaquemines and St. John) parishes," Lt. Col. Michael Kazmierzak, a Louisiana National Guard spokesman, told The Weather Channel Thursday morning. "We're still assisting with evacuations in both of those parishes."

"The big thing we've been doing through the night is with St. John's," he said. "We've assisted locals with evacuations of more than 3,000 people" there.

"The weather was definitely a major part of the difficulty," he added, "but when you get into darkness that creates a problem of its own, just being able to see and identify where the people are located."

Protected by federal levees, central New Orleans appeared to have escaped the worst of the storm, but rural areas of Louisiana and neighboring Mississippi were swamped and power outages widespread.

The first death from Isaac was reported in Mississippi early Thursday. A tow-truck driver died after a tree fell on his cab while he was trying to move a large tree from a main street in Picayune.

Two other deaths were confirmed Thursday evening; a man and woman were found floating in a flooded kitchen in Braithwaite, La. "Unfortunately, I believe we will find more bodies, " Plaquemines County Coroner's chief investigator John Marie told NBC News' Gabe Gutierrez.

More than 1,800 people died during Hurricane Katrina.

In Slidell, La., areas that had never flooded, including during Hurricane Katrina in 2005, saw up to five feet of water after drain pumps were overwhelmed.

Numerous homes and businesses were swamped, and police rescued 145 residents, NBC's Gabe Gutierrez reported from the scene.

"Water is currently backing up into the city through Bayou Pattasat," Mayor Freddy Drennan said in a statement on the city's website. "The pumps are currently unable to pump the water out as fast as it's coming in. It is anticipated that until Bayou Bonfouca recedes, the city will continue to be inundated with water."

Slideshow: Isaac moves inland

A downgraded Isaac floods coastal communities and forces new evacuations, but levees still hold.

Launch slideshow

Slidell is on the north side of Lake Pontchartrain, north of New Orleans. 

Around 850,000 homes and businesses across Louisiana and Mississippi were without power Thursday.

The Red Cross said almost 4,000 people were being accommodated in emergency shelters across Florida, Alabama, Mississippi, Louisiana and Texas.

Isaac is expected to be a soaker for days. 

"It's still pulling up all kinds of Gulf moisture, producing a large shield of rain," said Weather Channel hurricane specialist Carl Parker. 

"The worst of the rain has spun off to the east and north into Mississippi," added the Weather Channel's Mike Seidel, who reported from Baton Rouge, La., where rainfall was light.

Meteorologists have found Isaac vexing and tricky to pin down, describing the storm as “disorganized” and “uncharacteristic.”

George Dubaz, a New Orleans tour guide, put it more simply to Reuters: For him, Isaac was a lumbering "pain in the ass."

"Most of them blow through and are over with. This one is just hanging around too long," Dubaz said, comparing the storm to "somebody that comes for Mardi Gras and they stay two weeks afterwards."

President Barack Obama declared federal emergencies in Louisiana and Mississippi late Wednesday to supplement state and local recovery efforts beginning on Aug. 26, according to a White House statement.

In Plaquemines Parish, a sparsely populated area of south of New Orleans that is outside the post-Katrina federal levee system, dozens had to be rescued when a levee was overtopped Wednesday.

The storm pushed water over the 18-mile levee and put so much pressure on it that authorities on Thursday intentionally punctured the floodwall to relieve the strain.

Along the shores of Lake Pontchartrain just north of New Orleans, officials sent scores of buses and dozens of high-water vehicles to help evacuate residents.

Related: Blessing and curse for drought areas due to Isaac
Related: Resident reports on how post-Katrina defenses saved town
Related: Stories from the storm: 'They were screaming away'
Related: Isaac stirs up horrible memories for New Orleans residents

Isaac arrived seven years after Hurricane Katrina and passed slightly to the west of New Orleans, where the city's fortified levee system easily handled the assault. But, low-lying areas outside the city were harder-hit.

New Orleans set a daily record of 7.86 inches of rain on Wednesday, The Weather Channel reported, breaking the previous record for an August 29 -- 4.5 inches set by Katrina in 2005.

On Thursday, the rain was finally letting up in New Orleans but 40 percent of the city was still without power. 

"We're hearing from stores here that they're planning to open later today," reported NBC News' Danielle Lee. "This area relies on tourism, and they don't want to miss out on that Labor Day weekend travel."

"The mayor has been calling other stores who are able to sell emergency supplies, generators, things that may help people without power, asking them to please get open as quickly as possible," Lee added.

Police reported few problems with looting, after New Orleans Mayor Mitch Landrieu ordered a dusk-to-dawn curfew. He lifted the curfew Thursday.

Forecasters expected Isaac to move farther inland over the next several days, dumping rain on drought-stricken states across the nation's midsection before finally breaking up over the weekend.

In coastal Mississippi, officials used small motorboats Wednesday to rescue at least two dozen people from a neighborhood Isaac flooded in Pearlington. In addition, the National Weather Service said there were reports of at least three possible tornadoes touching down in coastal counties. No injuries were reported.

About 5.5 percent of total U.S. refining capacity was still idle Thursday because of Isaac, Reuters reported, although oil and gas companies prepared to reboot their operations as the storm weakened and water receded. The refiners had decided to shut down or run at reduced rates to protect their operations.

Meanwhile, gas prices jumped again in the wake of the storm; AAA reported they reached $3.82 nationally on Thursday.

The Associated Press, Reuters, NBC’s Gabe Gutierrez, Thanh Truong and Alastair Jamieson contributed to this report.

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