Reported February 2007

BACKGROUND: When developing a new model for predicting weather patterns or increasing warning times for flood-prone areas, scientists must rely on increasingly large, complex data sets collected by a wide range of disciplines. It is vital that these data systems conform to internationally adopted standards. The Common Alerting Protocol (CAP) is now running in parallel to more traditional systems used by the U.S. National Weather Service.

WHY WE NEED CAP: With adequate warning, people can react more quickly to natural or manmade hazards and disasters. There are many different warning systems, tailored to specific types of disasters for delivered through certain channels, but there is no public warning system that can reach everyone in every location at any time. More coordination is needed. CAP is intended to deliver warning messages that are universal; currently, such messages come from a wide variety of sources, often directly from news outlets.

HOW IT WORKS: CAP serves as a universal adapter for alert messages, replacing the diverse warning systems with a standard format, thereby paving the way for new alerting systems. It is essentially a "content standard:" a digital message format suitable to all types of alerts and notifications, including the U.S. National Emergency Alert System, the Internet, and systems designed for multilingual and special-needs populations.

CAP reduces the barriers of technical incompatibility. The sender can activate several different warning systems at once, reducing the cost and complexity of having to notify each system separately. People hear the warnings from several different sources, increasing the likelihood that they will heed those messages, rather than dismissing them as false alarms. CAP is compatible with broadcast radio and television, as well as public and private data networks.

Once it has been broadly deployed, CAP users will be able to monitor local, regional and national warnings of all types at any one time to get a complete picture of conditions.

WHAT'S THE FORECAST: Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Humankind has attempted to predict the weather since ancient times. For millennia people have tried to forecast the weather. In 650 BC, the Babylonians predicted the weather from cloud patterns. In about 340 BC, Aristotle described weather patterns in Meteorological. Chinese weather prediction lore extends at least as far back as 300 BC. Ancient weather forecasting methods usually relied observed patterns of events. For example, it might be observed that if the sunset was particularly red, the following day often brought fair weather. This experience accumulated over the generations to produce weather lore. Today, weather forecasts are made by collecting data about the current state of the atmosphere and using computer models of the atmospheric processes to project how the atmosphere will evolve.

If you would like more information, please contact:

Eliot Christian, Ph.D.
USGS
Reston, VA
echristian@usgs.gov