Aviation Weather 101: METAR Format, Type, Station Identifier, Date, Report Modifier

METAR FORMAT, YOU READY?

 Welcome back! In our last post, we introduced the basics of aviation weather reports. Today, we're going to dive deeper into the METAR/SPECI format, a crucial tool for every pilot. While it may look like a complex string of code, a METAR is simply a routine weather report, and a SPECI is a special, unscheduled one. Together, they provide a real-time snapshot of weather conditions at an airport. Let's break down the body of the report to understand what each part means.

Decoding the METAR/SPECI Body

11 Groups and the remarks of METAR/SPECI

 The body of a U.S. METAR/SPECI report consists of up to 11 groups and the remarks. When a weather element is not observed, its corresponding group is omitted. 

We will use the following example to guide our explanation:

METAR KOKC 011955Z AUTO 22015G25KT 180V250 3/4SM R17L/2600FT +TSRA BR OVC010CB 18/16 A2992 RMK A02 TSB25 TS OHD MOV E SLP132

 1. Type of Report

METAR KOKC 011955Z AUTO 22015G25KT 180V250 3/4SM R17L/2600FT +TSRA BR OVC010CB 18/16 A2992 RMK A02 TSB25 TS OHD MOV E SLP132

 The report begins by stating its type: 

• METAR (a routine, hourly report) 
• SPECI (a special report for significant weather changes).

2. Station Identifier

ICAO Continental Codes

METAR KOKC 011955Z AUTO 22015G25KT 180V250 3/4SM R17L/2600FT +TSRA BR OVC010CB 18/16 A2992 RMK A02 TSB25 TS OHD MOV E SLP132

 This is a four-letter ICAO code that identifies the airport. Pilots must understand the difference between ICAO and IATA codes.

• ICAO (International Civil Aviation Organization) codes are four-letter codes used for operational purposes by pilots, air traffic controllers, and aviation authorities. They are found on flight plans, weather reports, and navigation charts. Their structure has a geographical logic, where the first letter or two indicates the region and country, making them highly organized and unambiguous for technical use. For example, a "K" prefix signifies an airport in the contiguous United States.

• IATA (International Air Transport Association) codes are three-letter codes used for commercial purposes, primarily for passenger and cargo-related activities. They are the codes you see on airline tickets, baggage tags, and airport signs. They often relate to the city or airport name (e.g., "LAX" for Los Angeles or "JFK" for New York's Kennedy Airport) and do not follow a regional structure.

3. Date and Time of Report

METAR KOKC 011955Z AUTO 22015G25KT 180V250 3/4SM R17L/2600FT +TSRA BR OVC010CB 18/16 A2992 RMK A02 TSB25 TS OHD MOV E SLP132

 This group shows the observation time in Coordinated Universal Time (UTC), also known as Zulu time. The first two digits are the day of the month (01), followed by the hour (19) and the minutes (55). The time always ends with a "Z". For example, 011955Z means the report was taken on the 1st of the month at 19:55 UTC. 

4. Report Modifier

METAR KOKC 011955Z AUTO 22015G25KT 180V250 3/4SM R17L/2600FT +TSRA BR OVC010CB 18/16 A2992 RMK A02 TSB25 TS OHD MOV E SLP132

 The report modifier appears only when necessary. AUTO indicates the report was generated by a fully automated system without human input. If the report is a correction to a previous one, the modifier is COR.

Conclusion

 Mastering METAR/SPECI reports is a fundamental skill for any pilot. By understanding the first four groups of the report—Type, Station Identifier, Time, and Modifier—you've already taken a big step toward confidently interpreting aviation weather data. Stay tuned for our next post, where we will continue decoding the rest of the METAR report!