Reading a METAR beyond the remarks
Photo credit Divinity PriceWhether you are interested for informational purposes or even airline interview prep, let's take a look at a few METARs and decode them beyond their remarks.
This METAR was recorded from Baltimore/Washington International (BWI) on the 28th of the month 1354Z or 8:54AM local time. Winds are 300 at 11kts 10 statue miles of visibility, cloud layer broken at 6500FT AGL (above ground level). The temperature is 4 degrees Celsius and the dew point is -7 degrees Celsius. Altimeter setting is 29.94 Hg. That's the easy part. Now let's decode the remarks. A02 is a code that tells you that this weather reporting station has a precipitation discriminator. It can tell if rain, sleet, or snow is falling. SLP139 means Sea Level pressure measured in hectopascals.RELATED STORY:4 Question TAF and METAR quiz— Do you know your weather? Right after the "SLP" you see the number "1". If the number is 6 or less add a "10" in front of it. If it starts with a 7, 8, or 9 add a 9 in front of it. So this Sea Level Pressure 1013.9 MB. VIRGA is a weather phenomenon that warns you of potential downdrafts in the area. Downdrafts signal the dissipating stage of a thunderstorm. NE states that the VIRGA is reported 10 miles northeast of the field. T00391072 is a breakdown of the temperature and dew point. The first number 0 states the temperature is positive, a +3.9 degrees Celsius and the dew-point first number is a 1, a -7.2 degrees Celsius. Lastly, the $ means this station is in need of maintenance.
Let's see what's going on after the remark sections for this METAR. RAE13UPB13 is a code letting you know "RA" Rain "E" ended 13 minutes past the hour. "UP" is Unknown Precipitation "B" Began 13 minutes past the hour. PRESRR tells the trend of the pressure. "PRES" pressure is "RR" rising rapidly. P0001 the amount of precipitation that has fallen within the previous hour— 0.01 inches of rain fallen. And the T00280017 is the exact temperature dew point breakdown.
Lastly, let's review the items in this METAR that are different from the ones we previously reviewed. P0005 is the amount of precipitation that has fallen within the past hour and 0.05 inches of rain that has fallen within the past hour. 60032 is the amount of precipitation that has fallen within the previous 6 hours— 0.32 inches of rain have fallen. 70289 is the amount of precipitation that has fallen within the previous 24 hours— 2.89 inches of rain have fallen. Let's skip the T00200007. 10079 20018 is all coded temperatures within the previous 6 hours. 10079 tells you the highest temperature in the past 6 hours was 7.9 degrees Celsius. 20018 tells you the lowest temperature in the past 6 hours was 1.8 degrees Celsius. Lastly, 52040 tells you the barometric pressure tendency. The 5 is simply telling what the trend was within the previous 3 hours. The next number can be anything between 1-10. 1 meaning the pressure is rising rapidly, 10 meaning the pressure is decreasing rapidly and 5 meaning the pressure has stayed the same. This one is a 2 so the pressure is rising pretty rapidly. 040 add a decimal after the 4 to say the pressure has risen 4.0 hectopascals.
Can you decode this METAR? Leave what you think it states in the comments!Check out the aviation weather maps on GlobalAir.com