This handbook groups aviation weather information into five types:

Observations are raw weather data collected automatically by sensor(s), manually by trained weather observers, or by a combination of both. The observations can either be in situ (i.e., surface or airborne) or remote (e.g., weather radar, satellite, and lightning).

Analysis is the representation of an atmospheric variable (e.g., temperature, pressure) derived from a finite set of irregularly distributed observations onto a regular grid. Analyses of weather information are an enhanced depiction and/or interpretation of observed weather data.

Aviation weather advisories, including warnings and alerts, described in this handbook are primarily produced by the NWS. They inform the pilot and/or operator about aviation weather that may be a safety of flight risk, or that may need mitigation or avoidance depending on the aircraft’s and/or pilot’s certification, current operating limits, or capabilities.

Forecasts are the predictions of the development and/or movement of weather phenomena based on meteorological observations and various mathematical models. This handbook describes the many forecasts primarily produced by the NWS that are either specific to aviation or are public products of interest to aviation users.

Aviation weather tools are web-based applications that incorporate multiple weather products into a web-based interactive display.

The first of five types of aviation weather information discussed in this handbook is observations. Observations are weather data collected automatically by sensor(s), manually by trained weather observers, or by a combination of both, and are the basic information upon which forecasts and advisories are made in support of a wide-range of weather-sensitive activities within the public and private sectors, including aviation.

For this handbook, observations include the following:

Surface weather observations are fundamental to all meteorological services. Observations are the basic information upon which forecasts and warnings are made in support of a wide range of weather-sensitive activities within the public and private sectors, including aviation.