NOAA 2002-008
Contact: Carmeyia Gillis
NOAA News Releases 2002
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After years of trying to develop better hurricane forecast models, scientists at the National Weather Service's Environmental Modeling Center have upgraded the "Aviation Model," which now produces improved forecast guidance of tropical storms and hurricanes. The effort paid off when the AVN model outperformed all other forecast models for most of the 2001 Atlantic hurricane season, especially as Hurricane Michelle seemed poised to strike Florida. The National Weather Service is an agency of the Commerce Department's National Oceanic and Atmospheric Administration.

Advances In Model Guidance
Since the early 1990s, EMC modelers have worked to upgrade and fine-tune a higher resolution AVN to include better satellite data, aircraft observations, and to improve physics, which are incorporated into numerical weather model predictions that run on one of the world's fastest computers – NOAA's IBM supercomputer.

In the last three decades, NOAA has increased the accuracy of the forecasted track of a tropical storm three days in advance of possible impact from 450-nautical miles to 225-nautical miles. With the latest advancements to the AVN, that margin of error was further reduced to120 nautical-miles with Hurricane Michelle.

"We're extremely pleased with the results of our model development effort for hurricane forecasting," said Stephen Lord, director of EMC. "When the model forecasts improve, that translates into improved weather services, which save lives and property and reduce economic losses. That's what our effort is all about."

Lord credited the recent increase in model forecast accuracy to hurricane funding that EMC received from the U.S. Weather Research Program.

Improved Model Brings Success
"Hurricane Michelle was one of the most accurately forecast tropical events in the history of the National Hurricane Center," said Naomi Surgi, advanced projects leader for hurricanes at EMC. While Hurricane Michelle was churning in the Caribbean, threatening land fall in Cuba as a strong Category-Four hurricane, only the AVN model forecast a sharp turn toward the northeast away from the United States as it left the north coast of Cuba. During that time, all the other numerical guidance was forecasting a threatening situation to the Florida Keys and South Florida.

"It took a Herculean effort by the 53rd U.S. Air Force Reserves and NOAA aircraft to gather extra reconnaissance data that were crunched in the numerical prediction models at EMC," said Max Mayfield, the director of NOAA's National Hurricane Center. Mayfield cited improved forecast model guidance as pivotal in the accurate forecasting of Hurricane Michelle, and said the success was because of a team effort.

Hurricane Intensity, Inland Flooding Are Next
Although NOAA has made advancements in hurricane track modeling this past season, Surgi cautioned that hurricane science is complex and that no two hurricanes or hurricane seasons are alike.

EMC is also ready to enter a new modeling era to improve hurricane intensity forecasts and hurricane rainfall forecasts to address the threat of inland flooding. "This is the greatest scientific, numerical modeling and forecast challenge we will face over the next 10 years," said Surgi. As the nation witnessed with Tropical Storm Allison, which killed 41 people and caused $5 billion in damages, inland flooding poses a great danger.

The AVN model is NOAA National Centers for Environmental Prediction's Global Model, which is run four times a day at NCEP's Central Operations Center in Camp Springs, Md., to produce numerical guidance. National Hurricane Center forecasters use the model to predict the track of Atlantic hurricanes. During the last two years, NOAA has found the AVN had a 30 percent increase in the accuracy of hurricane tracking when compared with the results of the 1995-1999 Atlantic hurricane seasons.

NOAA's National Weather Service is the primary source of weather data, forecasts and warnings for the United States and its territories. NOAA's Weather Service operates the most advanced weather and flood warning and forecast system in the world, helping to protect lives and property and enhance the national economy.

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