What is a non-routine aviation weather report called?

A non-routine aviation weather report is known as a Special Report, or SPECI. This type of report is specifically issued when there are significant changes in the weather conditions that warrant immediate communication to pilots and air traffic controllers, such as sudden shifts in visibility or wind. Unlike regular METAR reports, which are issued at regular intervals and provide routine updates on weather conditions, a SPECI is produced to provide timely information about weather phenomena that could affect flight safety. This ensures that aviators receive the most current and relevant weather data to make informed decisions during flight operations.

In contrast, AIRMET and TAF reports serve other purposes; AIRMETs provide information on moderate weather phenomena that may affect aircraft, while TAFs (Terminal Aerodrome Forecasts) are focused on forecasting weather conditions for a specific airport over a set period. METAR updates refer to routine weather reports that describe observed conditions but do not account for sudden weather changes like a SPECI does.