The National Hurricane Center said Tuesday it will begin issuing storm watches and warnings about half a day sooner in the biggest change to its warning system in decades.
When a storm is approaching land, forecasters will now send watches advising that tropical storm conditions could be expected there in 48 hours, instead of 36 hours. Warnings of tropical storm or hurricane conditions will be issued 36 hours ahead, not 24 hours.
"It's really just the result of the accumulated improvements over time _ the track forecasts have been getting better incrementally year after year," said James Franklin, chief hurricane specialist at the center. "And there's been enough of an improvement now that we can feel comfortable increasing it."
But both forecasters at the center and some local emergency officials said the change likely won't affect how evacuations are ordered for coastal areas.
"The watches and warnings, they're great for public perception, but for emergency managers they're not terribly important for decision-making because we're on top of it already," said Clayton Scott, chief hurricane planner for Savannah and surrounding Chatham County on the Georgia coast.
He said emergency responders monitor storms closely and weigh possible evacuations well ahead of the hurricane center's watches and warnings. He said his agency needs 30 hours to evacuate residents and is prepared to order evacuations regardless of whether a hurricane warning has been issued.
But Franklin said having federal forecasters' warnings earlier could bolster local officials pleas for residents to leave when in danger.
"Any warning they give us, the earlier the better," said retired Lt. Col. Jerry Sneed, New Orleans' emergency preparedness director. "The more heads up I get, the more it is easier to implement this very difficult system of evacuating the city."
Even with the advance warning, though, emergency officials often run into residents resistant to leave.
"They'll say, 'Eh, it isn't that bad,'" said Irene Toner, director of emergency management in the Florida Keys, where hurricane preparations and evacuations are an annual ritual. "Unless it happens to you _ unless it really happens to you, unless it happens to a member of your family."
The hurricane center's forecasts have improved dramatically, cutting the error rate to roughly one-third its level in 1970 and half the level of 15 years ago, because of advances in computer models and increased satellite measurements of atmospheric conditions. But forecasters still struggle with the more complex issue of predicting a storm's intensity and say years more work is needed to increase accuracy in that area.
The changes apply to both the Atlantic hurricane season from June 1 to Nov. 30 and the eastern Pacific season from May 15 to Nov. 30.
Associated Press Writers Cain Burdeau in New Orleans and Russ Bynum in Savannah, Ga., contributed to this report.
National Hurricane Center: http://www.nhc.noaa.gov/