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Excessive Heat Program Piloted in Philadelphia Is Becoming Worldwide Model

NOAA image of beach scene in Ft. Lauderdale, Fla.Jan 11, 2005 ó The NOAA National Weather Service said it is developing a plan to expand the number of Heat/Health Watch Warning Systems from the current 16 cities to each municipality with a population exceeding 500,000. NOAA scientists made four presentations on this topic at the annual meeting of the American Meteorological Society in San Diego, Calif. (Click NOAA image for larger view of beach scene in Ft. Lauderdale, Fla. Click here for high resolution version, which is a large file. Please credit “NOAA.”)

HHWWS measures oppressive air masses affecting health and is part of a national focus on the special hazards excessive heat has on urban centers. Based on NOAA Weather Service storm data from 1994 to 2003, excessive heat is the number one weather-related killer, causing more fatalities per year than floods, lightning, tornadoes, hurricanes, winter storms and extreme cold.

"NOAA's National Weather Service currently issues excessive heat products to provide the nation advance notice of excessive heat events for the protection of life and property," said Mark Tew, NWS' public weather warning program leader. "Today, these products are issued based on a single heat index value derived from temperature and humidity. A national Heat/Health Warning System based upon empirical data would provide the NWS with tailored excessive heat guidance related to actual mortality and improve forecasts and warnings of excessive heat events," he explained.

According to Gary Szatkowski, meteorologist-in-charge of the NOAA Weather Service forecast office in Mt. Holly, N.J., "Philadelphia was the first city in the United States to implement the Heat/Health Warning System program and is now becoming the worldwide model for heat forecasting. Last summer the office upgraded its Heat/Health Warning System forecast capability to five days. The next generation program now uses gridded forecast data from the NWS National Digital Forecast Database as well as a more sophisticated statistical analysis of the excessive heat threat. It promises an improved level of performance."

This year, weather forecast offices serving Seattle; Dallas; Fort Worth, Texas; Phoenix; and Yuma, Ariz., implemented the system, joining Washington, D.C.; Chicago; St. Louis; Cincinnati; Dayton, Ohio; New Orleans, La.; Little Rock, Ark.; Memphis, Tenn.; Shreveport, La., Lake Charles, Miss.; and Jackson, Miss.

"The excessive heat program that started in Philadelphia is proving to be a model for the rest of the country," said Brig. Gen. David L. Johnson, U.S. Air Force (Ret.), director of the NOAA National Weather Service. "Studies using three years of collected data indicate that 117 lives were saved by the Philadelphia heat program."

Studies funded by the U.S. Environmental Protection Agency and the Southern Regional Climate Center indicate very hot weather increases the number of deaths in large urban areas. "More people die of heat than any other environmental event. The Heat/Health Watch Warning System is the first and only meteorological tool that identifies oppressive air masses that historically diminish people's health," said AMS session chair, Laurence Kalkstein, senior research fellow in the University of Delaware's Center for Climatic Research and developer of the new system. "A custom made system is developed for each urban area, based on specific meteorology for each locale as well as urban structure and demographics."

According to Kalkstein, "During the average summer in the United States there are at least 1,500 excess deaths attributed to heat. If deaths by heart attacks, strokes or respiratory illness are above normal during a heat wave, we consider it a heat-related death, the medical examiner would not."

Cities in the northeastern and midwestern United States have the strongest weather mortality relationships, because weather variability, rather than heat intensity, is the single important factor in defining human sensitivity to heat, according to Szatkowski.

People living in highly variable summer climates are ill adapted to extreme heat, mainly because it occurs irregularly. "For this reason, temperate cities like Philadelphia, New York, Boston and Chicago exhibit extreme increases in the number of deaths reported when an intense heat wave occurs compared to many tropical cities in the world. This is one reason that early season heat waves are associated with higher mortality, because people within the city population acclimate to the heat as the hot season continues," Szatkowski explained.

"When the eastern U.S. experiences excessive heat waves, it becomes a major concern for urban centers because of the high fatality rates from this kind of weather event," said Dean Gulezian, director, NOAA Weather Service Eastern Region. "The Heat/Health Warning System program has had great success in reducing heat related mortalities in Philadelphia. New York City has also expressed interest in this program."

With the recognition of heat as possibly the greatest weather related killer in many areas of the developed world, there has been a growing impetus to develop warning systems to permit urban health agencies and local meteorological offices to issue advisories to the public if a dangerous heat wave is imminent. "This has led to an important collaboration to construct Heat/ Health Watch Warning Systems for vulnerable large cities around the world," said Kalkstein. "The Philadelphia program provided the model used in developing programs for Shanghai, China; Toronto, Canada; and six cities in Italy: Rome, Palermo, Milan, Genoa, Bologna and Turin."

The NOAA Weather Service is the primary source of weather data, forecasts and warnings for the United States and its territories. The NOAA 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.

NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and providing environmental stewardship of the nationís coastal and marine resources. NOAA is part of the U.S. Department of Commerce.

Relevant Web Sites
NOAA Heat Safety

NOAA Weather Service Eastern Region

Heat Wave: A Major Summer Killer (PDF)

Media Contact:
Marcie Katcher, NOAA Weather Service Eastern Region, (631) 244-0149