The Spotter's Role

The National Weather Service (NWS) has a number of devices for detecting severe thunderstorms. Included in these are radar, satellite, and lightning detection networks. However, the most important tool for observing thunderstorms is the trained eye of the storm spotter. While radar is used quite often in severe storm warnings, conventional weather radar will only indicate areas and intensities of precipitation. It does not give any indication of cloud formations or wind fields associated with a storm. Doppler radar, which is being introduced across the country, will give some indication of air motions inside a storm. Doppler radar, though, will not give these indications down to ground level. It is impossible for any radar to detect every severe weather event in its coverage area, and radar occasionally suggests severe weather when, in fact, none is present.

Satellite and lightning detection networks provide general thunderstorm locations and are extremely valuable in data-sparse regions (such as over mountainous terrain or over bodies of water). They help to identify persistent thunderstorm areas and can be of aid in flash flood forecasting. These systems provide little in the way of quantitative real-time information, though, and are not especially helpful during times of fast-breaking severe weather.

As a trained spotter, you perform an invaluable service for the NWS. Your real-time observations of tornadoes, hail, wind, and significant cloud formations provide a truly reliable information base for severe weather detection and verification. By providing observations, you are assisting NWS staff members in their warning decisions and enabling the NWS to fulfill its mission of protecting life and property. You are helping to provide the citizens of your community with potentially life-saving information.

Objectives of this Handbook

During the past several years, researchers have uncovered a tremendous amount of information regarding severe thunderstorm structure and behavior. New theories regarding thunderstorm formation and tornado development have been presented. Storm-intercept teams have correlated these theories with observed visual features. Our current understanding of the thunderstorm is markedly more complete than it was just ten years ago.

With this handbook and the Advanced Spotter Training Slide Set which was released a few years ago, the time has come to pass this new under-standing on to you, the spotter. Only by providing fresh training material can the NWS expect to maintain what has become a very important group of observers.

Prerequisites for Using this Guide

The information contained in this guide is not for the novice spotter. It is recommended that spotters go through two or more basic spotter training sessions and have some experience at actual storm spotting before attempting the intermediate/advanced training material. Spotters should be comfortable with the basic concepts of storm structure and storm spotting. Obviously, spotters should have a desire to learn the latest concepts of tornado and severe thunderstorm behavior.
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