If you’re preparing for the FAA’s Part 107 test, you might’ve come across two important topics – METARs and TAFs. Reading METARs and TAFs can be a mental juggernaut if you’re not familiar with aviation phraseology and aviation weather. These are two types of aviation weather reports that provide accurate weather data of a specific region. Deciphering these two types of weather reports is an important aspect of the Part 107 test.
Here’s what a standard METAR report looks like:
METAR KCBM 151755Z 00000KT 10SM SCT012 BKN029 OVC120 M06/M07 A2998 RMK IR18 SLP156
Reading all this coded data may seem difficult. However, once you familiarize yourself with the fundamental abbreviations and their meanings, you can read any METAR or TAF report.
What exactly are METARs and TAFs?
METARs: Meteorological Aerodrome Report (METAR) is an observation of current surface weather reported in a standard international format. METARs are updated in case any significant weather change is observed. Airports and weather stations are the two primary sources that issue METARs.
TAFs: A Terminal Aerodrome Forecast (TAF) is a weather report established for the five statute mile radius around an airport. TAF reports are usually given for larger airports. Each TAF is valid for a 24 or 30-hour time period and is updated four times a day at 6:00 P.M CST (0000Z), 12:00 A.M CST (0600Z), 6:00 A.M CST (1200Z), and 12:00 P.M (1800Z). TAF utilizes the same abbreviations as METAR. However, its format is slightly different from METAR. Given below is what a standard TAF report looks like:
TAF KPIR 111130Z 1112/1212
TEMPO 1112/1114 5SM BR
FM1500 16015G25KT P6SM SCT040 BKN250
FM120000 14012KT P6SM BKN080 OVC150 PROB30
1200/1204 3SM TSRA BKN030CB
FM120400 1408KT P6SM SCT040 OVC080
TEMPO 1204/1208 3SM TSRA OVC030CB
TAFs may look intimidating because of their multi-line format but they follow the same parameters as METAR with a few add-ons.
How to Read METARs?
A typical METAR report has 11 informational parameters. In a sequential order they are:
1. Type of report: The first text that you’ll find in any METAR report is the type. There are two types – METAR and SPECI. METAR is the standard weather report while SPECI is a special weather report issued to update a METAR or convey a significant weather change.
2. Station Identifier: The next bit of information is called a station identifier. A station identifier is a four-letter code as established by the International Civil Aviation Organization (ICAO). Out of the 50 states, 48 states have their code starting with the letter ‘K’ which denotes the United States. This is followed by three letters denoting the airport identifier. For example, in the code ‘KCBM’, ‘CBM’ stands for the Columbus airport in Mississippi. Only for the states of Alaska and Hawaii, the first two letters of the code begin with ‘PA’. You can find the entire list of station identifiers here.
3. Date and Time: Presented in a six-digit format, the date and time are the next information of a METAR report ( Ex: 151755Z). The first two digits are the date. The next four digits signify the time in a coordinated universal time (UTC) format, also known as ‘Zulu’ time. You can convert it to central standard time (CST) by subtracting six hours from the Zulu time. For example, 1755Z is the same as 11:55 A.M
4. Modifier: Sometimes METAR reports may contain a modifier that denotes that the report came from an automated source or that the report was corrected. The modifier can be ‘AUTO’ which means the report came from an automated source or it can be ‘COR’ which identifies a corrected report sent out to replace an earlier report. In the case of a ‘COR’ modifier, the error is not displayed; only the corrected report is shown.
5. Wind Speed: The wind speed is denoted in five digits with the knots unit (KT). The first three digits indicate the direction the true wind is blowing from in tens of degrees. If the wind is variable, it is reported as ‘VRB.’ The last two digits indicate the speed of the wind in knots unless the wind is greater than 99 knots, in which case it is indicated by three digits. If the winds are gusting, the letter “G” follows the wind speed (G26KT). After the letter ‘G,’ the peak gust recorded is provided. If the wind direction varies more than 60° and the wind speed is greater than six knots, a separate group of numbers, separated by a ‘V,’ will indicate the extremes of the wind directions.
6. Visibility: This means the prevailing visibility. It is denoted with a number or fraction followed by the letters ‘SM’ which indicates statute miles. For example, 10SM means 10 statute miles.
7. Weather: Weather is broken down into two parts – qualifiers and weather phenomenon (+TSRA BR). First, the qualifiers of intensity, proximity, and the descriptor of the weather are given. The intensity may be light (–), moderate ( ), or heavy (+). Here in the example ‘+TSRA BR’, +TSRA means heavy thunderstorms and rains. BR indicates mist. Additional weather occurrences are mentioned at the end of the report in the remarks section. Given below is the legend table with all the qualifier and weather phenomenon abbreviations and their meanings:
8. Sky Conditions: Sky conditions represent the amount of cloud coverage. This value is always reported in the sequence of amount, height, and type or indefinite ceiling/height (vertical visibility). For example, ‘SCT012 BKN029 OVC120.’ This example can be interpreted in three parts:
Scattered Clouds at 1200ft
Broken Clouds at 2900ft
Overcast at 12000ft
Different cloud types can be found at different altitudes, thus the need for multiple descriptors. Given below is a list of codes for cloud conditions:
9. Temperature and Dew Point: The air temperature and dew point are always given in degrees Celsius (C) or (18/17). Temperatures below 0 °C are preceded by the letter ‘M’ to indicate minus. For example, ‘M06/M07’ can be interpreted as a -6°C temperature and a -7°C dew point.
10. Altimeter Setting: The altimeter setting is the level of mercury in an altimeter of an aircraft. This is used to gauge the current pressure above sea level in the unit inHg (inches of mercury). This code starts with the letter ‘A’ which stands for Altimeter followed by four digits. For example, ‘A2995’ is read as the current pressure is 29.95 inHg.
11. Remarks: This is the extra bit of information mentioned at the end of a METAR report. Remarks always begin with the letters ‘RMK.’ followed by extra weather information that is relevant but does not fit in the main report. The information contained in this section may include wind data, variable visibility, beginning and ending times of a particular phenomenon, pressure information, and various other information deemed necessary. For example, ‘RMK RAE04 P0000 PRESFR’ means rain ended 4 minutes past the hour, no precipitation was recorded (P0000) within the hour and there has been a fall in pressure (PRESFR).
Remarks can be harder to interpret and are one of the most confusing parts of a METAR report. On a clear day, remarks may not exist at all in a report. Either way, remarks are not as important as the main report.
How to Read TAFs?
Reading TAFs is relatively simple if you’re already familiar with reading METAR reports. TAFs are issued four times per day and are valid for a period of 24-30 hours. TAF reports are established for larger airports and for the five statute-mile radii around that airport. TAF utilizes the same descriptors and abbreviations as METAR. Here is the sequential order of parameters in a TAF report:
1. Type of Report: A TAF can be either a routine forecast (TAF) or an amended forecast (TAF AMD)
2. Station Identifier: The four-letter ICAO code of an airport is mentioned here. Same as METAR.
3. Date and Time: Six letter information, where the first two letters signify the date and the last four signify the time in UTC or Zulu (Z).
4. Valid Periods: This is a new addition to TAF. This bit of information tells us the range of dates and times for which the TAF will remain valid. In the example ‘0812/0912’, the TAF report starts on the 8th day of the month at 1200Z and will end on the 9th day of the month at 1200Z. Therefore, this is a 24 hour TAF report.
5. Wind Direction and Speed: This consists of five digits. The first three indicate the wind direction in degrees and the last two digits tell the wind speed in knots (KT). Same as METAR.
6. Visibility: Just like in METAR, the visibility is denoted by a number or fraction which tells us the statute miles (10SM).
7. Weather: Weather phenomena are coded in the TAF reports in the same format as the METAR.
8. Sky Conditions: Given in the same format as the METAR. Only cumulonimbus (CB) clouds are forecast in this portion of the TAF report as opposed to CBs and towering cumulus in the METAR.
9. Forecast Change Group: Two types of abbreviations are used to denote sudden changes in the weather forecast. If it is a temporary change ‘TEMPO’ is used followed by the period until which the change will last. Example: TEMPO 2209/2211. This means that there will be a temporary change that will occur on the 22nd day of the month from 0900Z to 1100Z. This is followed by the general weather phenomenon descriptors used in the main report.
The second type of abbreviation that is used is ‘FM’ which is used when a rapid and significant change occurs within the hour. FM means the word ‘FROM’ and this indicates that the changes are permanent. If you see FM written on a TAF report, anything followed by FM will then become the main report. Example: FM 221800. This means that the forecast on the 22nd day of the month from 1800Z onwards will be considered as the main forecast.
10. PROB: This is the probability of thunderstorms or precipitation occurring within the coming hours. The ‘PROB’ abbreviation is followed by the probability percentage number. Example: PROB30.
Conclusion
Once you have all the descriptors and abbreviations memorized, reading METARs and TAFs will become much easier. Go through Chapter 13 of the Pilot’s Handbook of Aeronautical Knowledge (PHAK) for more detailed information. Alternatively, if you want to prepare for the part 107 test with professional drone pilot training schools, we have shortlisted the top 5 training schools in the US.
