Meteor streams that form as a result of cometary activity around perihelion consist of both structured and background components. The former are often referred to as trails. A trail is created at each perihelion passage as a result of the meteoroids' range of orbital periods. Trail locations can be precisely calculated by numerical integrations, allowing predictions of meteor outbursts and storms. The initial distribution of meteoroids, which relates to the meteor shower profile, depends on the meteoroid production rate and ejection velocity distribution as functions of heliocentric distance and on solar radiation pressure. The profile can gradually evolve owing to other radiative forces. This paper reviews such work on these aspects of shower predictions.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html