Lecture 3 (9/23) METR 1111 METAR Surface Observation Code

What is METAR? METAR is the the international standard code for hourly and special surface weather observations. It roughly translates from French as Aviation Routine Weather Report

Typical METAR Report KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= All lines after the first are indented. Each METAR report ends with an = sign

Station Identifier KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= KOKC is the station identifier. - All station identifiers begin with a K. - This identifier stands for Oklahoma City.

Some other near-by stations KTUL = Tulsa KITC = Wichita KDFW = Dallas/Fort Worth Let’s not forget us!! - KOUN = Norman

Date & Time KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= 31 indicates it is the 31 st day of the month 1156Z tells us it’s 1156 Zulu (Greenwich time). All observations taken at the same time around the world

What is Zulu Time? Think of it like military time (24 hours) To get Central Daylight Time (CDT) subtract 5 hours. 1156Z = 6:56AM CDT Central Standard Time (CST) subtract 6 hours. 1156Z = 5:56AM

Winds KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= 120 means the wind is FROM 120º. Here, we have an ESE wind. 15 is the wind speed (in knots) G22 means the wind is gusting to 22 kts KT just gives you the units (knots)

Visibility KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= 10SM means the visibility is at least 10 statute miles. Visibility may decrease if the air is hazy, foggy, dusty, or precipitation is falling.

Cloud Abundance & Height KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= SCT350 means there are scattered clouds at 35,000 feet. Just add 2 zeros to the end OVC420 means it’s overcast at 42,000 ft. You can have BKN(broken) or FEW(few) In terms of clouds, FEW < SCT < BKN < OVC

Temperature & Dew Point KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= The number before the slash, 08, gives you the temperature in °Celsius. M02 gives you the dew point temperature in °Celsius. The M means the dew point is minus 2°C

Altimeter Setting KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= A2999 stands for an Altimeter setting of inches of mercury (in Hg). Used by pilots and skydivers to help them figure out how high above the ground they are.

Remarks & Precipitation Discriminator KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= RMK stands for ‘remarks’. It is in every METAR report and separates the standard data from extra data. A02 means this site has a precipitation discriminator. A01 would mean it didn’t.

Sea Level Pressure KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= SLP = Sea Level Pressure. This is the pressure the barometer would read if it were at sea level. We use this instead of the actual measured station pressure so we can compare the pressure at 2 stations with different elevations.

More Fun with Sea Level Pressure KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= Add either 10 or 9 in front of 136 to get the sea level pressure. Add a decimal before the last #. You have to decide whether you add 9 or 10. This station is at mb. Typical values range from 970 mb to 1030 mb.

Temperature & Dew Point KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= T indicates temperature & dew point group. Gives temperature and dew point to a tenth of a degree. Use this if you’re going to convert to °F.

More Fun With Temperature & Dew Point KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= A zero in the 1 st or 5 th number means it is positive. A one means it’s negative indicates the temperature is 7.8 °C means the dew point is –1.8 °C.

Amount of Precipitation KOKC Z 12015G22KT 10SM SCT350 OVC420 08/M02 A2999 RMK A02 SLP136 T P0012= P indicates precipitation It gives you the precipitation since the last hourly report to the.01” P0012 means 0.12” of precip fell in the last hour.

That’s It! There’s much more to know about METAR code. ml You can get observations in the METAR form at: her/weather_interface.html her/weather_interface.html Or

For next week: Read Chapter 4 “Storms and Fronts” (pages 47 – 62) Complete homework 3 (METAR surface observation code)