Impact of Isaac on metro Atlanta unpredictable

Tropical Storm Isaac could bring several inches of rainfall to metro Atlanta this week, along with a chance of winds, tornadoes and creek flooding. But the storm's changing path may spare Atlanta the more severe impact that meteorologists first feared.

Georgia Power crews left for Florida early Sunday morning to help with any outages caused by the storm, but turned around later in the day and came back home following brightened weather forecasts, said a spokesman, John Kraft.

Some Sunday flights to Florida have already been canceled, and the Republican Party has scratched the first day of its convention, Monday.

As clouds roll in Monday, the chance of rain will increase, Channel 2 Action News meteorologist Brad Nitz said. On Monday expect a mostly sunny start, he said, but by Tuesday the chance of rain is 40 percent. That rises to 60 percent Wednesday and Thursday.

"We could see two to four inches of rain," Nitz said. "Isolated spots with higher amounts is possible as Isaac moves inland across the Southeast." A National Weather Service meteorologist agreed there could be two to four inches of rain here, or as much as eight to ten, depending on the path of the storm and its trailing bands of rain.

The storm has already caused flooding and some deaths in the Caribbean, and threatens Florida as it hosts the Republican National Convention in Tampa.

Earlier, National Weather Service meteorologist Brian Lynn said that if the storm develops into a hurricane as expected and its track goes over central or eastern Alabama, that would place the more severe weather along the eastern side of the storm over Atlanta sometime Wednesday. The storm also could spawn tornadoes, Lynn said.

"Now is the time to prepare," he said.

Preparation is still a good idea, NWS Meteorologist Dan Darbe said Sunday, because the storm's path is wide and unpredictable. However, it's moved west.

"The current official forecast has it now going into southern Mississippi as a Category 2 hurricane Wednesday morning," Darbe said. That track "would definitely have lesser impacts on the metro Atlanta area," although, he added, "now it's a similar track to what Katrina was, and we still got 16 tornadoes out of Katrina across Georgia."

Southwest Airlines has canceled Sunday's afternoon and evening flights to Ft. Lauderdale, Ft. Myers, and West Palm Beach, and customers can request refunds at 1-800-435-9792, according to the airline. For some flights it is offering flexible re-booking within 14 days at southwest.com and 1-800-435-9792.

Depending on the actual storm track, the heavy rains could lead to minor to moderate flooding in some parts of Georgia, said Wylie Quillian, a hydrologist with the National Weather Service's Southeast Forecast Center.

As the clouds roll in, the daytime temperatures will drop to the mid 80s from upper 80s. The nighttime lows will be in the upper 60s and low 70s.

Winds here could be in the 20 mile-per-hour range, with gusts up to 30 m.p.h., Darbe said.

Isaac's eastern edge promises rain for Georgia this week, but it is unlikely to cancel the state's drought, a National Weather Service hydrologist said Sunday. If the storm tracks more easterly than currently expected, it could drop more rain and ease Georgia's areas with "exceptional" drought to "severe" or "moderate."

But on its current course -- admittedly proving unpredictable -- the rain is unlikely even to do that much, said Hydrologist Kent Frantz.

It would take 12 to 15 inches of rain over a couple days to lift the drought completely, as "drought-buster" Tropical Storm Debby did this June for north Florida and Southeast Georgia, Frantz said.