Aerodrome Met Report – Ibex Aviation Academy

Aerodrome Meteorological Reports are classified as METAR, SPECI, and SPECIAL.
METAR is a routine aviation weather report issued every 30 minutes by meteorological offices. A trend (landing) forecast is appended.
SPECI is a selected special weather report issued for significant changes in weather conditions since the previous METAR.
SPECI is issued immediately for deterioration in weather conditions and after a 10-minute interval for improvements.
A trend forecast is appended to SPECI reports.
SPECIAL is a local version of SPECI intended only for the originating ATC unit and is not transmitted to other stations.

Report Type and Aerodrome: METAR followed by the ICAO aerodrome indicator (e.g., METAR VIDP).
Date and Time: Given in UTC (e.g., 270630Z).
Wind Direction: True wind direction expressed in three digits at 10° intervals.
Extremes of variable wind direction during the previous 10 minutes are indicated (e.g., 26005KT 220V360).
Wind Speed: Mean wind speed is reported in knots or metres per second. Gust speed is included when it exceeds the mean speed by 10 knots or more.
P99 indicates gusts exceeding 99 knots.

Visibility: Prevailing visibility over at least half of the aerodrome.
Visibility up to 10 km is reported in metres. Visibility greater than 10 km is coded as 9999.
If visibility is lower in a particular direction, it is also reported (e.g., 3000 1400SW).
Runway Visual Range (RVR): Reported when RVR is less than 1500 m.
The prefix P indicates a value greater than the reported figure.
RVR trend is indicated using:
- U – Improving
- D – Deteriorating
- N – No Change
Example: R27R/P1500U

The present weather group consists of a Qualifier, Descriptor, and Weather Phenomenon.
The Qualifier indicates intensity and proximity.
The Descriptor describes the type of precipitation or obscuration.
The Weather Phenomenon specifies the actual weather condition.
Example: -SHRA = Light Rain Showers.

Cloud height is reported above aerodrome level (QFE) in ascending order of cloud amount.
FEW = 1–2 oktas.
SCT = 3–4 oktas.
BKN = 5–7 oktas.
OVC = 8 oktas.
High clouds are reported only when they cover a significant portion of the sky.
Special cloud types such as CB or TCU are specifically indicated (e.g., FEW009 BKN015 TCU).

Vertical Visibility (VV): Reported in hundreds of feet.
VV002 indicates a vertical visibility of 200 ft.
If clouds cannot be observed due to obscuration, VV/// is reported.
Temperature and Dew Point: Reported in whole degrees Celsius.
Values of 0.5°C are rounded up to the next whole number.
Negative temperatures are prefixed with M.
QNH: Reported using the prefix Q (e.g., Q0991) and always rounded down for flight safety.

CAVOK (Ceiling And Visibility OK) may replace visibility, RVR and present weather groups.
CAVOK Criteria:
- Visibility greater than 10 km.
- No cloud below 5000 ft or the Minimum Sector Altitude (MSA), whichever is higher.
- No Cumulonimbus (CB) clouds.
- No significant weather.
Minimum Sector Altitude (MSA): Provides at least 300 m (1000 ft) obstacle clearance within a radius of 46 km (25 NM) from a radio navigation aid.

Recent weather is reported if significant weather occurred during the previous hour or since the last METAR.
A maximum of three recent weather events may be reported.
Example: RERA = Recent Rain.
Wind shear is included when reported by pilots or forecast by meteorological services.
WS ALL RWY indicates wind shear affecting all runways.

Surface Wind:
- Mean speed ≥ 10 kt.
- Direction changes by ≥ 60° with speed ≥ 10 kt.
- Mean speed ≥ 10 kt with speed variation ≥ 15 kt.
Visibility: Passing through 800, 1500, 3000 or 5000 m.
RVR: Passing through 150, 350, 600 or 800 m.
Present Weather: Onset, cessation or intensity changes in freezing precipitation, freezing fog, moderate/heavy precipitation, drifting or blowing snow, sand, dust, duststorm (DS), thunderstorm (TS), sandstorm (SS), squalls and funnel clouds (tornado or waterspout).
Clouds: Cloud base BKN or OVC at 30, 60, 150, 300 or 450 m.
Cloud amount changes from SKC/FEW/SCT to BKN/OVC or vice versa.
Vertical Visibility: Passing through 30, 60, 150 or 300 m (100, 200, 500 or 1000 ft).
Surface temperature changes by 2°C or more since the previous observation.

SPECIAL is an abbreviated plain-language version of SPECI intended for local ATC.
SPECIAL reports are not transmitted to other stations.
They are issued for:
- Visibility of 2000 m or 4000 m.
- Cloud base of 90 m or 120 m measured by a ceilometer or celiograph.

AIREP or PIREP are weather reports transmitted by pilots during climb and en-route flight.
Example:
AIREP IA120 BHP 1200 UTC FL350 M554 270/04KT TS SCT CB TOP FL400 =
An AIREP consists of three sections:
- Section 1: Flight identification, position, time and flight level.
- Section 2: Estimated Time of Arrival (ETA) and endurance.
- Section 3: Air temperature, wind, thunderstorms, turbulence, icing and humidity.
Aircraft equipped with data link automatically transmit weather reports every 15 minutes during cruise.
During the first 10 minutes of climb, automated reports are transmitted every 30 seconds.
Non-routine weather such as wind shear, icing and turbulence is transmitted immediately.
After landing, volcanic activity reports are forwarded to the Aerodrome Meteorological Office when applicable.
AIREP is generally not required for:
- Aircraft not equipped with RNAV.
- Flights shorter than 2 hours.
- Aircraft within 1 hour of landing.
- Flights below 1500 m (5000 ft).