Utilizing the latest-generation excessive heat concepts in NOAA's National Weather Service forecast office operational environment

After the major heat wave of 1993, the City of Philadelphia embarked on a new way of identifying and mitigating the impacts of excessive heat. Research conducted by the University of Delaware showed success during a 1995 heat wave, and that work resulted in an operational program introduced in 1997 at the National Weather Service (NWS) Forecast Office in Mt. Holly, NJ for the city of Philadelphia. This new program supplemented traditional ways of determining the need for excessive heat warnings by expanding the criteria to include variables for time of year, and length of excessive heat event.

The latest generation of this program has brought additional changes as air mass types are also used as a critical factor in determining the threat from excessive heat. This latest generation program now uses gridded forecast data from the NWS National Digital Forecast Database. This new system was implemented last year. Several periods of excessive heat in the summer of 2005 have provided variable operational experience with this new system.

Operating a successful modern excessive heat program requires a concerted training effort for the meteorological operations staff of the NWS office, as well as local governmental partners and media. Education outreach on this topic is essential, as the impacts of excessive heat are still poorly understood by many people, even after the disastrous heat event in Europe during the summer of 2003.

How well the new system has operated during the summer of 2005 will be presented, as well as how it affected the forecaster decision-making process. Comparisons between this latest generation program and the previous program used operationally in the Weather Forecast Office since 1997 will also be made, as well as comparisons to observed weather parameters (e.g., Heat Index).