Flight Safety Essentials: Key Aviation Weather Terms for Preflight Checklist
Flying comes with its own language, especially when it comes to weather. Terms like AIRMETs, SIGMETs, and PIREPs might seem like jargon, but understanding them could make all the difference in your preflight and in-flight planning. Chris Dunn—a professional pilot, flight instructor, and meteorologist with over 30 years in broadcasting—breaks down key weather terms every pilot needs to know. From AIRMETs and SIGMETs to PIREPs, Chris simplifies the jargon, helping you confidently interpret your preflight weather briefing and stay informed throughout your journey
Flight Instructor: Chris Dunn
Updated Nov 8, 2024
Part of learning to fly means learning the lingo of aviation. You’ll need to know many acronyms and abbreviations such as CAVU, VASI, VOR, ILS, IMC, VFR, and the list goes on. When receiving your preflight weather briefing, pay particular attention to three of these terms: AIRMETs, SIGMETs, and PIREPs (well, NOTAMs are important too, but here we’re mainly focusing on weather in this guide).
Decode the Sky
OK! It’s definition time:
AIRMET – Airman’s Meteorological Information. Essentially, it’s weather information that applies to all aircraft operations, particularly for light airplanes (which most of us use for training). AIRMETs are issued to warn of hazardous weather not covered in a regular forecast. This includes moderate icing, turbulence, winds over 30 knots, ceilings below 1000 feet, and other adverse conditions you’d rather not fly into.
SIGMET – Significant Meteorological Information. A sigmet is issued whenever hazardous weather may affect ALL aircraft over a specified area. Think of a sigmet as an airmet on steroids. A sigmet will include advisories on severe icing, severe or extreme turbulence, and dust or sandstorms that may reduce in-flight visibilities below 3 miles. A Convective Sigmet is issued for similar hazards, except they are associated with convective activity (generally speaking, that means thunderstorms). A convective sigmet is usually issued when severe thunderstorms, tornadoes, or squall lines are forecast.
PIREP – A Pilot report of actual, in-flight observed conditions. Pireps are especially valuable because the weather guessers on the ground have no other way of verifying their forecast. A pirep can also serve as a warning to other pilots about conditions that may not have been forecast, such as icing or turbulence. That’s something you might want to know before heading in that direction. For more on how you can contribute pireps into the system, check out the Sky Spotter program from AOPA’s Air Safety Foundation.
All this valuable weather information is available for the asking, but you need to know who to ask and where to reach them! When you receive your preflight weather briefing, the briefer should advise you of any adverse weather conditions right from the start. If any AIRMETs or SIGMETs are in effect for your route, they’ll tell you right away, which can sometimes make your decision for you pretty quickly.
But what if you’re en route and an AIRMET is issued, or other pilots ahead of you report significant turbulence? Here’s another acronym—EFAS! It stands for Enroute Flight Advisory Service, also known as Flight Watch, on a common frequency of 122.0. It’s designed to provide updated, pertinent weather information while you’re in flight.
And here’s yet another acronym—HIWAS: Hazardous In-Flight Weather Advisory Service. It contains a summary of aviation weather warnings, along with AIRMETs, SIGMETs, convective SIGMETs, and urgent PIREPs. You can find HIWAS reports continuously broadcast over select VOR stations.
Remember, your preflight weather briefing should be just the beginning of your search for weather information before taking to the skies. You can access continuous weather reports throughout your flight, and you should if you have any doubt about whether to press onward.
As my father always told me, “There are safe pilots, and there are dead pilots. Which would you rather be?” It’s blunt but certainly gets the point across.