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WeatherWeather
Weather is where most flights begin and end. These guides decode the reports and forecasts pilots read every day, from METARs and TAFs to winds aloft, icing and convective hazards, and explain what each field is actually telling you.
27 guides
- Weather
Temperature inversions and stable air
What a temperature inversion is, how it makes the air stable, and why that explains haze, fog, smooth rides, trapped pollution, low cloud and wind shear.
4 min read Read - Weather
Mountain waves and rotor
How stable air over high ground sets up mountain waves and the violent rotor beneath, the cloud signs that reveal them, and why they deserve respect.
4 min read Read - Weather
Pressure systems: highs, lows, ridges and troughs
What highs, lows, ridges and troughs are, the weather each brings, which way the wind circulates around them, and how to read them on a pressure chart.
7 min read Read - Weather
How to read a surface analysis chart
Decode a surface analysis chart: isobars and the pressure gradient, highs and lows, warm, cold and occluded fronts, and the big picture before the METAR.
4 min read Read - Weather
Volcanic ash and the SIGMET
Why volcanic ash is so dangerous to aircraft, how Volcanic Ash Advisory Centres and SIGMETs warn you, and why an ash SIGMET runs longer and starts earlier.
4 min read Read - Weather
The jet stream and clear-air turbulence
What a jet stream is, where it sits near the tropopause, and why the wind shear around it produces clear-air turbulence that arrives with no cloud to warn you.
5 min read Read - Weather
Cloud types and what they tell a pilot
The ten cloud genera grouped high, middle and low, heaped versus layered cloud, and how to read what each tells you about stability and the weather ahead.
4 min read Read - Weather
Turbulence reporting and intensity scales
What light, moderate, severe and extreme turbulence mean, why intensity is judged by the aircraft's reaction rather than a guess, and how pilots report it.
3 min read Read - Weather
The tropopause and where weather lives
What the tropopause is, why it sits higher over the equator than the poles, and why nearly all of a pilot's weather happens in the troposphere below it.
4 min read Read - Weather
Sea and land breezes
Why coastal winds reverse between day and night, how a sea breeze and a sea-breeze front form, and what the diurnal circulation means for a coastal aerodrome.
7 min read Read - Weather
Aircraft icing explained
How airframe ice forms, the difference between rime, clear and mixed ice, why supercooled large droplets are so dangerous, and where to find the forecast.
6 min read Read - Weather
TAF change groups: TEMPO, BECMG, PROB and FM
A deeper look at the change groups that make a TAF a forecast: the meaning of FM, BECMG, TEMPO and PROB, with a worked example that decodes them in order.
5 min read Read - Weather
The International Standard Atmosphere (ISA)
What the ICAO International Standard Atmosphere is, its sea-level values and lapse rate, and how ISA deviation underpins altimetry and density altitude.
3 min read Read - Weather
Density altitude and aircraft performance
What density altitude is, how to estimate it from pressure altitude and temperature, and why hot, high and humid conditions rob an aircraft of performance.
5 min read Read - Weather
Altimetry: QNH, QFE and the standard setting
What QNH, QFE and the standard setting do to your altimeter, the difference between transition altitude and level, and the EASA and FAA conventions.
7 min read Read - Weather
Fog, mist and the dewpoint spread
Why the gap between temperature and dewpoint predicts fog, the difference between mist and fog in a METAR, and the main fog types from radiation to advection.
9 min read Read - Weather
Air masses and fronts
What an air mass is and how it gets its character, the difference between warm, cold and occluded fronts, and the weather each one brings to a flight.
7 min read Read - Weather
Wind shear and low-level wind shear
What wind shear is, why microbursts and gust fronts are so dangerous near the ground, how it changes aircraft performance, and the warnings that flag it.
9 min read Read - Weather
How to read a SIGMET and an AIRMET
What SIGMETs and AIRMETs warn of, the phenomena codes, how long each stays valid, and a worked SIGMET decoded field by field, with the US differences.
6 min read Read - Weather
Thunderstorms and convective weather
What makes a thunderstorm, the three stages of its life, the hazards from turbulence to hail and microbursts, and how the convective SIGMET warns you.
8 min read Read - Weather
Reading winds and temperatures aloft
How to decode a winds and temperatures aloft forecast, the coding trick for strong winds, with a worked example and how to use it for cruise planning.
8 min read Read - Weather
How to read an ATIS
What the ATIS broadcast contains, how the information letter and runway-in-use work, how it differs from a METAR, and the EASA/UK and FAA conventions.
7 min read Read - Weather
Setting personal weather minimums
What personal minimums are, how to build a set from ceiling, visibility and wind, and how to use the PAVE and IMSAFE checklists to keep your own limits honest.
7 min read Read - Weather
Runway visual range (RVR)
What RVR is, how a transmissometer or forward-scatter meter measures it, why it differs from reported visibility, and how to decode the RVR group.
7 min read Read - Weather
How to read a TAF
Decode a Terminal Aerodrome Forecast: the FM, BECMG, TEMPO and PROB change groups, the validity period, and how a forecast differs from a METAR.
5 min read Read - Weather
Flight rules: VFR, MVFR, IFR and LIFR
What the colour-coded flight categories mean, the ceiling and visibility boundaries set by the NWS and FAA, and why a category is not the legal VFR minima.
7 min read Read - Weather
How to read a METAR
A plain-language guide to decoding a METAR field by field, with a worked example and the EASA/UK and FAA differences that trip pilots up.
5 min read Read