A SPECI is a special aviation weather report that is issued to report rapidly changing weather conditions at an airport. SPECIs are used in addition to routine METAR reports, which are issued every hour, to provide pilots with up-to-date information on weather conditions that could affect their flight.
Definition of SPECI
A SPECI is a special report that is issued by an airport’s weather observer or automated weather station to update pilots on rapidly changing weather conditions.
These reports are used to provide pilots with current information about weather conditions that could affect their flight, such as thunderstorms, fog, or rapidly changing winds.
Purpose of SPECI
The purpose of a SPECI is to provide pilots with timely and accurate information about weather conditions at an airport.
This information is critical for safe flight operations, as pilots need to be aware of weather conditions that could affect their flight, including takeoff and landing.
SPECIs are especially important for airports that experience rapidly changing weather conditions, such as thunderstorms or fog, which can develop quickly and pose a danger to aircraft.
Issuance of SPECIs
SPECIs are issued in addition to routine METAR reports, to provide pilots with up-to-date information about rapidly changing weather conditions at an airport. Here are some important things to know about the issuance of SPECIs:
When SPECIs are issued
SPECIs can be issued at any time, in addition to the routine hourly METAR reports. They are issued as soon as possible after a significant weather change is observed or reported by the airport’s weather observer or automated weather station.
Criteria for issuing a SPECI
The criteria for issuing a SPECI are laid out in the aviation weather reporting system, and are based on the following factors:
- Visibility changes
- Cloud ceiling changes
- Significant weather changes, such as thunderstorms, hail, or tornadoes
- Wind speed or direction changes
- Temperature changes
If any of these factors meet or exceed the reporting criteria, a SPECI will be issued.
Rapidly changing weather and SPECIs
SPECIs are especially important in situations where weather conditions are rapidly changing, such as during thunderstorms, heavy rain, or fog.
In these situations, regular METAR reports may not provide pilots with the most up-to-date information, and a SPECI can be issued to update pilots on any changes to the weather conditions.
Examples of when SPECIs are issued
SPECIs can be issued for a variety of reasons, including:
- Thunderstorms or other severe weather
- Rapidly changing wind conditions
- Reduced visibility due to fog, smoke, or haze
- Snow or ice accumulation
- Temperature changes that affect runway conditions
Missed approach due to a SPECI report
In rare cases, a SPECI report can cause a missed approach or go-around, where the pilot must abort the landing and circle back around for another attempt.
This can happen if the SPECI reports a significant change in weather conditions, such as a sudden drop in visibility or a strong crosswind, that makes it unsafe to land.
In these cases, the pilot will follow the missed approach procedures for that particular airport, which are designed to ensure a safe go-around and landing.
Decoding a SPECI
Decoding a SPECI can be a bit intimidating at first, but once you understand the format and the codes used, it becomes much easier to read. Here are some important things to know about decoding a SPECI:
How to read a SPECI
A SPECI report is broken down into several sections, including the airport identifier, the observation time, and the weather conditions. Here is an example of what a SPECI report might look like:
SPECI KJFK 081215Z 09006KT 1 1/2SM -RA BR SCT005 BKN010 OVC015 12/11 A3000 RMK AO2 P0001 T01170106
In this example, the airport identifier is KJFK, the observation time is 12:15Z (Zulu time), the wind direction is 090 degrees at 6 knots, the visibility is 1 1/2 statute miles, and there is light rain and mist. The cloud cover is scattered at 500 feet, broken at 1000 feet, and overcast at 1500 feet. The temperature is 12 degrees Celsius, the dew point is 11 degrees Celsius, the altimeter setting is 30.00 inches of mercury, and there is a precipitation amount of 0.01 inches.
Wind direction in a SPECI
The wind direction in a SPECI report is always given in degrees true, not magnetic. This means that the wind direction is based on true north, rather than magnetic north. Pilots must convert the wind direction to magnetic heading when flying.
Validity period of a SPECI
A SPECI report is valid for a short period of time, typically one hour. This means that pilots must be sure to check for any updates or new SPECIs before they take off or land at an airport. If there are any significant changes to the weather conditions, a new SPECI will be issued, even if the previous one has not yet expired.
Comparison with METARs
While both SPECIs and METARs are types of aviation weather reports, there are some important differences between the two. Here are a few key distinctions to keep in mind:
Differences between SPECIs and METARs
- METARs are routine reports, issued hourly, whereas SPECIs are special reports issued whenever there are significant changes in weather conditions.
- METARs provide information on the current weather conditions at an airport, while SPECIs provide updates on rapidly changing weather conditions that could impact flight safety.
- SPECIs are typically more detailed and specific than METARs, since they are designed to provide pilots with up-to-the-minute information about changing weather conditions.
| Feature | Routine METAR | Special SPECI |
|---|---|---|
| Reporting frequency | Hourly | As needed |
| Criteria for issuance | None, routine | Rapidly changing weather |
| Validity period | One hour | 30 minutes |
| Coverage | Airport only | Specific location |
| Wind direction and speed | Average | Momentary |
| Cloud cover | SCT/BKN/OVC | FEW/SCT/BKN/OVC |
| Visibility | Statute miles | Statute miles |
Routine reports vs. special reports
In general, routine weather reports are issued hourly and include information on cloud cover, visibility, wind speed and direction, temperature, dew point, and barometric pressure. These reports are known as METARs.
Special weather reports, on the other hand, are issued whenever there are significant changes in weather conditions. These reports are known as SPECIs.
Examples of rapidly changing weather conditions that might prompt the issuance of a SPECI include sudden drops in visibility due to fog or heavy rain, strong wind gusts, or rapid changes in temperature.
Use of SPECIs at Your Destination
If a SPECI has been issued at your destination airport, it’s important to take the necessary steps to ensure a safe landing. Here are a few things to keep in mind:
A SPECI was issued at your destination. What now?
If a SPECI has been issued at your destination airport, it means that there have been significant changes in weather conditions since the last routine report was issued.
This could indicate rapidly changing weather conditions that could impact flight safety. As a result, it’s important to be prepared for the possibility of an unstable approach or missed approach.
Clearing a SPECI
Once the conditions that prompted the issuance of a SPECI have passed, the report can be cleared. This is typically done by issuing a new routine report that reflects the current weather conditions.
Pilots should be aware that until the SPECI is cleared, the weather conditions at their destination airport may be significantly different from what is reported in the most recent routine report.
Frequently Asked Questions
Here are some common questions and answers about SPECIs:
What is a SPECI? A SPECI is a special aviation weather report that is issued when there are significant changes in weather conditions that could impact flight safety.
When is a SPECI issued? SPECIs can be issued at any time, but are typically issued when there are rapidly changing weather conditions that could impact flight safety.
Is wind direction in a SPECI in degrees true or magnetic? Wind direction in a SPECI is reported in degrees true, not magnetic.
How long is a SPECI valid for? A SPECI is valid for a period of one hour from the time it was issued.
How do you decode a SPECI? To decode a SPECI, you will need to understand the various codes and abbreviations used in aviation weather reports. A decoding chart can be found in the Aeronautical Information Manual (AIM).
If you have any other questions about SPECIs or aviation weather reports in general, be sure to consult the AIM or speak with a qualified aviation weather specialist.
Conclusion
SPECIs are an important tool in aviation weather reporting, providing critical information to pilots and air traffic controllers about rapidly changing weather conditions that could impact flight safety.
By understanding the criteria for issuing a SPECI, how to read and decode a SPECI, and how to respond to a SPECI at your destination, pilots can take appropriate actions to ensure the safety of their flight.
As such, it is important for pilots to be familiar with the use and significance of SPECIs in aviation weather reporting.
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