NOAA supercomputer predicted hit, underestimated force

Supercomputers helped the National Oceanic and Atmospheric Administration accurately predict where Hurricane Katrina would hit, but agency officials say predictions about the intensity of Hurricanes Isabel and Frances may have been more accurate.

“Two and a half to three days before the hurricane hit, we were pretty much zoomed in on the Louisiana/Mississippi Gulf coast as where the hurricane would hit,” said Jack Beven, a hurricane specialist at the NOAA Tropical Prediction Center. “It’s probably not the most accurate we’ve been, but it’s certainly pretty accurate.”

The center will not have final forecast verification numbers available for several weeks.

“The one reason perhaps that we had a little trouble earlier in the storm’s life was that we underestimated how much the high pressure ridge over the southern [United States] would push the hurricane southward,” Beven said. The storm grew stronger than expected, particularly over the Gulf of Mexico where it reached Category 5, he added.

Forecasters derive guidance about the power and route of a hurricane, largely from an IBM-built supercomputer within the National Weather Service, a subdivision of NOAA.

Supercomputer models play a key role when a storm is about three to five days from the coast, said Kevin Cooley, director of central operations at the NOAA National Centers for Environmental Prediction.

During the course of Hurricane Katrina, “there was a lot of warning provided. The storm basically went where the forecasters thought it was going to go,” Cooley said.

Over the last year, NWS upped its supercomputing capacity threefold from .5 teraflops to 1.5 teraflops as part of its long-term contract with IBM.

The terms of the contract require the company to deliver increases in computational ability about every 24 months.

Even more sophisticated hurricane-intensity forecasting may be on the horizon. By year’s end, NOAA expects to award a contract for a new high-performance computer system. NOAA will consolidate its supercomputing resources so all of its agencies can benefit from research and development, officials said. One contractor will be responsible for the system.

The thinking behind the consolidation is that “the agency has the capability to efficiently and effectively direct HPC resources to making progress on this problem,” Cooley said, adding that NOAA officials are currently engaged in live demonstrations with vendors.

Hurricanes are not the only NOAA priority, Cooley said. A clearer picture of the long-term climate, tsunamis and global earth observations also take up computational units.

“My experience is that problems that tend to have some immediacy to them and affect life and property tend to get a lot of attention, as they should,…but it’s not the only problem,” Cooley said. “Just about every significant improvement in forecasting is predicated on improvements in modeling.”