(MSA above ground : LSZB 10000 FT, LSZH 8000 FT, LSGG 12000 FT, LFSB 6000 FT) — Page 531, Lesson 504

I want to walk you through a set of METAR reports and then a question about what METAR itself means. Let’s start with the reports themselves — these are actual weather observations from four aerodromes in Switzerland. First, let’s decode the structure. Each line begins with the ICAO four-letter aerodrome identifier. For example, LFSB is Basel-Mulhouse-Freiburg. Then comes the wind group: 24008KT means the wind is from 240 degrees true at 8 knots. Next, 9999 is the horizontal visibility in metres — 9999 means 10 kilometres or more, which is the maximum coded value. Then SCT050 is the cloud group: scattered cloud at 5,000 feet above aerodrome level. 18/11 is temperature/dew point in degrees Celsius. Q1017 is the QNH, the pressure setting to give altitude above mean sea level, in hectopascals — here 1017 hPa. RERA means recent rain — rain that has stopped within the last hour. NOSIG means no significant change expected in the next two hours. Now the second report: LSZH is Zurich. VRB02KT means wind variable at 2 knots — too light to assign a fixed direction. 9000 is visibility 9,000 metres. BKN080 is broken cloud at 8,000 feet. 21/14 temperature/dew point. Q1022 pressure. NOSIG again. Third: LSGG is Geneva. 22006KT wind from 220 degrees at 6 knots. 9999 visibility 10 km or more. BKN090 broken cloud at 9,000 feet. 17/15 temperature/dew point. Q1008 pressure. RERA recent rain. NOSIG. Fourth: LSZB is Bern-Belp. 28012KT wind from 280 degrees at 12 knots. 9999 visibility 10 km or more. OVC100 overcast cloud at 10,000 feet. 16/12 temperature/dew point. Q1012 pressure. BECMG 5000 means the weather is expected to change — becoming — visibility 5,000 metres within the next two hours. Now, the question asks: What does the term METAR signify? Let’s look at the four options. Option a says a METAR is a flight forecast, issued several times daily. That’s wrong — a METAR is an observation, not a forecast. Option b says a METAR is a landing forecast added to the actual weather report as a brief prognostic report. That’s also incorrect — a landing forecast is a TREND, not the METAR itself. Option c says a METAR signifies the actual weather report at an aerodrome and is generally issued in half-hourly intervals. That is correct. METAR stands for Meteorological Aerodrome Report — it is the routine actual weather observation at an aerodrome, typically issued every 30 minutes. Option d says a METAR is a warning of dangerous meteorological conditions within a FIR. That’s wrong — that would be a SIGMET or AIRMET, not a METAR. So the correct answer is c. A METAR is the actual weather report at an aerodrome, issued in half-hourly intervals. Now, the next question asks: Does the following report make sense? — but the report itself isn’t shown in this excerpt. We’ll need the next part of the book to see what report they’re referring to.