Can someone decode this METAR reading for me?

Question

i know there was another question on it but after reading that question and the answers... i still dont fully understand it...

this METAR was taken from www.live-atc.net for KSEA

KSEA 212253Z 36007KT 10SM FEW095 SCT250 11/03 A2972 RMK AO2 SLP073 T01110028

(KSEA obviously means Seattle, but i dont understand the rest of it

Answer 1

US SEATTLE:  

21ST DAY OF THE MONTH,  

22:53 ZERO ZONE,  

WIND FROM 360º TRUE AT 7 KNOTS,

SURFACE VISIBILITY 7 STATUTE MILES,  

FEW CLOUDS  9500 FEET ABOVE,  

SCATTERED CLOUDS 25,000 FEET ABOVE,

TEMPERATURE 11º CELSIUS,

DEW POINT TEMPERATURE 3º CELSIUS,

ALTIMETER SETTING 29.72" HYDRARGYRUM.  

REMARKS:  

AUTOMATED OBSERVATORY WITH PRECIPITATION SENSOR.  

SEA LEVEL PRESSURE 1007.3 MILLIBARS.

TEMPERATURE 1.1º CELSIUS,

DEW POINT TEMPERATURE 2.8º CELSIUS.

Answer 2

Here's a source for decoding METARs: http://www.nws.noaa.gov/oso/oso1/oso12/d...

For your example, the numbers before the Z are date and time (21st day of the month at 2253Z).  Zulu time is the same as UTC.  In the case of Seattle, subtract 8 hours for local time: 1453 or 2:53pm.

Next is the wind.  36007KT translates to winds out of 360 (due north) at 7 knots.

10SM is the visibility in statute miles.  Normally, 10SM means that the visibility is AT LEAST 10 miles.  Anything less than 10 is the actual visibility.

Listed next in your example are the sky conditions.  Add two zeros to the end of each number to get the height of the cloud bases.  In this case, there is a "few" layer with bases 9500 feet above the ground and a "scattered" layer at 25,000 feet above the ground.  "Few" means there are clouds with up to 2/8 sky coverage.  "Scattered" means 3/8 to 4/8 coverage.  "Broken" would be 5/8 to 7/8 coverage.  "Overcast" is complete coverage.

11/03 is the temperature and dewpoint in degrees Celsius.  The temperature is 11 degrees C and the dewpoint is 3 degrees C.

A2972 is the local altimeter setting.  Add a decimal in the middle and you get 29.72 inches of mercury.

Everything after the RMK (remarks) is supplementary information.  This information is usually the hardest to decode.

A02 means that the observation was taken by an automated sensor with a precipitation discriminator, meaning it can tell the difference between drizzle, rain, sleet, and snow.

SLP073 is the local altimeter setting in millibars.  It stands for Sea Level Pressure.  To decode this, add a 9 or 10 in front and a decimal before the last number.  Adding the 9 or 10 is a matter of just knowing what makes the most sense.  Standard pressure is 1013 millibars, so it's a matter of making the number closest to that.  In this case, it's 1007.3 millibars.

Information following the T is a more exact temperature/dewpoint reading.  Four digits are for the temperature, four are for the dewpoint.  The first number in the group of 4 will either be a 0 or 1.  0 means positive, 1 means negative.  The next three digits in each group of four is the actual temperature or dewpoint.  Just add a decimal before the last number.  Your example, T01110028 breaks down to 0111, which means the temperature is Positive 11.1 degrees Celsius, and the dewpoint is 0028, or Positive 2.8 degrees Celsius.

EDIT:  For your additional question, yes, that's true.  The standard for setting the altimeter in the United States is inches of mercury, but much of the rest of the world uses millibars (hectopascals).  29.92 inches is the same as 1013.2 millibars.

Cherokee, if you're serious (and we live in the same part of the country), send me an email.  That sounds like fun if I'm not out traversing the world.

Answer 3

coffeebuzz has given a very thorough and correct answer.

Coffee, want to come here and  teach my ground school held at the local Community College next week?  I am down with the flu (real bad)

we are to have our first  meeting tues, class is on tues, wed, and friday nights 6:00 - 9:30 or so. pay is negotiable