RSS

METARs – The Other Foreign Language

27 Oct

Two years ago when I started taking flying lessons I realized that there was a whole new language to learn for aviation.  It was the language of weather. It wasn’t like any other language I had attempted to learn.  It didn’t require me to roll my R’s like I had to for Spanish.  I didn’t have to worry about pronunciation like I did when I was learning German and French.  It definitely wasn’t like learning a computer programing language as in BASIC or DBASE.  This was just maybe the language I was meant to learn.  I could understand it.

This is a METAR (pronounced ME-TAR).  It is one source of  the weather conditions for the St. Cloud Regional Airport last evening.

KSTC 262353Z 25031G41KT 10SM -RA BKN023 BKN029 OVC037 04/02 A2875 RMK AO2 PK WND 26046/2339

At first when my CFI(Certified Flight Instructor) had me look up the weather on ADDS(Aviation Digital Data Service). It made no sense to me at all.  It was just a group of numbers and letters unlike any I had seen before.  My CFI explained that each section meant something.  The first part KSTC is the airport identifier.  KSTC is the airport identifier for the St. Cloud Regional Airport in Minnesota where I took my flying lessons.

The next section is the date and time section.  The 26 of 262353Z stands for the 26th of the month.  2353Z stands for ZULU time.  The time is based on a 24 hour clock like military time.  In St. Cloud at this time of year you need to subtract 5 hours from the 2353 which would be 1853 and subtract 12 hours to get the local time for the weather which is 6:53pm.

After the date and time comes the wind direction and velocity, 25031G41KT.  At 6:53pm on the 26th of October the winds were reported from 250 degrees(almost straight out of the west) at 31 knots gusting at times to 41 knots.  This is not a day that I would be flying a Cessna 152 or any other small plane.  In fact the commercial planes at Chicago O’Hare were grounded yesterday morning due to the strong winds.

The next section of the METAR is the runway visual range, 10SM.  In the case of yesterday’s METAR it was 10 statute miles or better.  After the visual range is the weather.  The weather was reported as -RA which is interpreted as light rain.

Cloud levels are next.  They report the type and height of the clouds.  In yesterday’s METAR the clouds were reported as BKN023 BKN029 OVC037.  Last night’s clouds at 6:53pm were BKN(Broken) which means that 5/8 to 7/8 of the sky was covered with clouds and the clouds were 2300 feet above ground level. You add two zeros at the end to get the height.  001 becomes 100 above ground level, 010 becomes 1000 AGL. There is also another layer of BKN clouds at 2900 above ground level. The third level is an overcast level at 3700 feet above ground level.  The lowest level of broken or overcast layer becomes the ceiling for VFR pilots.  In last night’s weather the cloud ceiling was 2300 feet above ground level.

The temperature and dew point section is next in the METAR.  In last night’s METAR the temperature is 04/02 which means the temperature is 4 degrees Celsius and the dew point is 2 degrees celsius.

The next section in the METAR is the altimeter.  It is represented by A2875 which is 28.75 inches of Hg.  The interesting fact about this altimeter setting is that it is the lowest recorded altimeter setting in St. Cloud for decades.  The St. Cloud area and most of Minnesota has been experiencing very strong sustained winds in the past 24 hours which is very unusual for our area.  The current altimeter setting is important.  Each time you depart or land at an airport it is important to have the current altimeter setting set in your airplane.

The last section of the METAR is the RMK or remark section where a briefer can add supplemental information.  They are represented by remark codes.  In last evening’s RMK section it was noted that the PK WND or peak wind in the past hour was from 260 degrees at 46 knots and it occurred at 2339Z or 6:39pm local time.

You can check out all kinds of weather information at the website ADDS

http://aviationweather.gov/adds/metars/

Try your hand at tonight’s METAR for KSTC.  I know you can do it!

KSTC 280353Z 31025G33KT 10SM FEW026 OVC034 04/M01 A2977 RMK AO2 PK WND 29037/0321 SLP097 T00391006

A few clues …

280353-5 (for local time) = 10:53pm pm the 27th of October.

FEW means clouds reporting more than 0 to 2/8 cloud cover

M in 04/M01 means it is a sub-zero value.







Advertisements
 
Leave a comment

Posted by on October 27, 2010 in education, Flight training

 

Tags: , , , ,

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

 
%d bloggers like this: