Aviation Weather Services Vocabulary

Vocabulary flashcards covering aviation weather categories, service outlets, briefings, surface observations (METAR), aerodrome forecasts (TAF), pilot reports (PIREP), and in-flight advisories (AIRMET/SIGMET).

VFR (Visual Flight Rules)

A flight category defined by a ceiling above 3,000 feet AGL and visibility greater than 5 statute miles.

Marginal VFR (MVFR)

A flight category defined by a ceiling from 1,000 to 3,000 feet AGL and visibility between 3 and 5 statute miles.

IFR (Instrument Flight Rules)

A flight category defined by a ceiling less than 1,000 feet AGL or visibility less than 3 statute miles.

Low IFR (LIFR)

A flight category defined by a ceiling less than 500 feet AGL or visibility less than 1 statute mile.

Flight Service Station (FSS)

A service outlet accessible via 1-800-WX-BRIEF or frequency 122.2 MHz that provides preflight briefings, in-flight updates, altimeter settings, and flight plan processing.

Standard Briefing

A detailed preflight briefing covering departure, route, and destination weather, requested when no previous weather data has been received and departure is within the hour.

Abbreviated Briefing

A shortened preflight briefing requested to update or supplement previously obtained weather information.

Outlook Briefing

A preflight weather briefing requested when a proposed departure time is six or more hours in the future.

AWOS (Automated Weather Observation System)

An automated weather station equipped with sensors to measure surface conditions such as wind, pressure, and precipitation near an airport.

ASOS (Automated Surface Observing System)

A surface observing system that uses automated sensors to provide continuous weather observation data for an airport area.

METAR (Aviation Routine Weather Report)

A standardized surface weather observation report recorded about 10 minutes before the hour and issued routinely every hour.

SPECI

A special, unscheduled weather observation report issued between routine METARs when a significant change in weather occurs.

AO2 Station

A METAR remark code designating an automated weather station equipped with a precipitation discriminator that can identify specific types of precipitation.

SLP (Sea Level Pressure)

A METAR remark code reporting sea level pressure in hectopascals or millibars, corrected for station temperature fluctuations.

PIREP (Pilot Report)

A report of actual in-flight weather conditions experienced by pilots, including parameters such as cloud tops, turbulence, icing, and wind shear.

TAF (Terminal Aerodrome Forecast)

A weather forecast covering an area within 5 statute miles of an airport, valid for 24 or 30 hours and updated four times daily.

FM Group (FROM Group)

A TAF forecast change indicator denoting prevailing weather conditions expected to change significantly in less than one hour.

TEMPO Group

A TAF change indicator indicating temporary weather fluctuations expected to last less than an hour per instance and cover less than half of the specified forecast period.

PROB30

A TAF code indicating a 30% probability of occurrence for a forecast weather hazard or phenomenon.

BECMG Group (Becoming)

A TAF indicator denoting a gradual change in forecast weather conditions expected over a longer timeframe, typically two hours or more.

AIRMET

A graphical weather advisory issued every 6 hours by the National Weather Service regarding hazards particularly critical to smaller aircraft, such as moderate icing, turbulence, low ceilings, and strong surface winds.

SIGMET

A significant weather advisory issued for severe non-convective weather events affecting all aircraft, valid for up to 4 hours.

Convective SIGMET

A weather advisory issued hourly at 55 minutes past the hour for severe convective hazards, lines of thunderstorms, embedded thunderstorms, or severe weather such as tornadoes and large hail, valid for up to 2 hours.