This is called a METAR, or Meteorological Aviation Report. They’re generated by weather stations at airports! It’s a shorter way to describe the weather for aviation purposes.
The METAR consists of two parts, the body and the remarks. We’ll talk about the body first.
METAR: There can be two reports, either the standard METAR or a significant weather event, which in that case will begin with SPECI.
KBNA: This is the station name. The first letter will either be a K or a C. U.S. stations start with a K and Canadian stations start with a C. The next 3 letters are the station name. This METAR came from Nashville International Airport in Tennessee.
272153Z: This is the date and time of the report. The first two numbers (27) are the day of the month. In this case, this report came on the 27th. The next 4 numbers (2153) are the time. This was reported at 21:53 Z, which is 4:53 PM CDT.
02005KT: This tells you the wind information. The first 3 numbers (020) tell you the direction of the wind, given in degrees. In this one, the wind is coming from the north east. The next two numbers (05) tell you the wind speed. In this report, the speed is 5 knots.
10SM: This is the visibility. Here, the visibility is 10 statute miles.
BKN070: This is the cloud coverage. The first 3 letters (BKN) show how much of the sky is covered. In this case, BKN means Broken where 51-87% of the sky is cloudy. The next three numbers (070) are the height of the cloud base in hundreds of feet. Here, we have broken clouds at 7000 feet.
27/11: This is the temperature and dew point, in Celsius. Here, the temperature is 27°C while the dew point is 11°C. This converts to ~81°F and ~52°F.
A3008: This is the altimeter reading. This gives the pressure in inches of mercury. This would be the pressure if this station were at sea level.
Now we have the Remarks section. This section is only added when appropriate. This will start with RMK.
AO2: This says that there is a precipitation discriminator at this station, and it is an automated station!
SLP180: This is the sea level pressure. SLP stands for sea-level pressure. The three numbers after it (180) give reading in hectopascals. If the number is less than 500, a 10 is put in front. If it’s more than 500, a 9 goes in front. A decimal goes in between the second and third numbers. In this case, the sea level pressure would read as 1018.0 hectopascals.
T02720111: This is the precise temperature and dew point, as before it is given in degrees Celsius. The first four set of digits (0272) is the temperature. The reason for the 0 in front is that it designates the sign. If it’s a 0, it’s positive. If it’s a 1, it’s negative. In this case, the temperature is 27.2°C. Same process for the dew point. In this case, the dew point is 11.1°C.
To learn more about aviation weather, click here!
©2017 Weather Forecaster Jennifer Naillon