In an amphitheaterlike room, emergency responders stared at a giant video screen showing the Chattanooga area centered in an angry red oval.
"We're real concerned about long-lived, strong tornadoes developing and moving toward this area, the plateau counties and Southeast Tennessee," meteorologist David Hotz told the room via conference call from the National Weather Service in Morristown, Tenn. "As you can see, we have a lot of risk for a huge chunk of our area, and I would not be surprised if we wake up [today] and the risk is higher."
After Hotz's presentation Tuesday, Hamilton County Emergency Management Chief Bill Tittle told the group that weather forecasters have advised him that the highlighted red area has a 70 percent chance of seeing a tornado.
"Normally in these storm systems, our chances range from 10 to 15 percent, and our highest chances are usually 20 to 25 or 30 percent," Tittle said, hoping to drive home the need for planning in each person's respective department.
Tonight's forecast also includes warnings of severe thunderstorms, large hail, wind gusts of 40 and 50 mph and sporadic downpours of rain.
Late Tuesday, the cold front behind the local warnings already had edged into a storm system that has dumped historic rain on the Mississippi River region and dropped a killer tornado on the town of Vilonia, Ark., north of Little Rock. The twister killed four people, and four others died in nearby floods. In Mississippi, a 3-year-old girl was killed when a storm knocked a tree onto her home.
Authorities said the storms would continue to fire up and move eastward through the night and today, with the cold front provided the extra energy that may produce tornadoes.
On Tuesday, Don Allen, director of Hamilton County Emergency Management, reminded the group of emergency workers about the most recent storm to cause local tornado damage.
"When the tornado [Feb. 28] hit Signal Mountain and Red Bank, we had a 12 percent chance [of a local tornado]," Allen said. "Two hundred fifty homes were affected."
Tittle said the Tennessee Emergency Management Agency already has activated the state Emergency Operation Center to deal with "possible historic river flooding in West Tennessee."
Tittle and Allen said they often stage briefings when there are extreme forecasts, but they acknowledged that Tuesday's briefing was larger than usual.
In the room were John Stuermer, director of the Hamilton County 911 Center, at least half a dozen other Chattanooga police officials, Signal Mountain Police Chief Boyd Veal, local hospital representatives, an EPB official and many others.
Stuermer said the briefing made it clear to him that he'll need to bring in additional people to man the 911 phones tonight.
"We may add some channels to our communications, too," he said.
Lacie Newton, spokeswoman for EPB, said the power company will watch the weather closely "and likely hold additional crews throughout the day (today)."
TVA, too, has been tracking the forecast and flooding concerns. The utility has been releasing lots of water to make room for more rainfall - a feat that is harder than it may seem since the agency doesn't want to add to flooding problems in the Tennessee River as it runs through West Tennessee to the already flooded Ohio and Mississippi rivers.
Hotz said the storm models showing the weather system's march eastward toward the Cumberland Plateau reminded him of a swarm of tornadoes that swept across Tennessee in November 2002.
Those storms left record death and destruction in the Southeast, but Tennessee was hardest hit. Authorities said 16 people were killed and at least 80 were injured. East Tennessee towns in the path of those tornadoes were Mossy Grove, rural Crossville and Manchester.
Allen said a similar outbreak of storms struck closer to home in March 1997 when about a dozen twisters were reported in 11 Tennessee counties, including Hamilton.
East Brainerd and Hickory Valley residents that year awoke to find 44 people injured when about 50 homes and 18 apartments were destroyed.
As Paul Barys, weatherman for the WRCB TV Channel 3, wrapped up his forecast Tuesday evening, he urged Chattanoogans to be prepared.
"It could get rough," he said. "I may take over the newscast."
On the serious side, he told residents to get a weather radio and have a plan for safety.
"When I get home tonight, we're going to talk about where we need to go in our house and where we live if a tornado happens," he said.