Meteorology
Meteorology tests the atmosphere, pressure, wind, clouds, fronts, icing, thunderstorms, tropical systems and the interpretation of METAR and TAF. In Mauritius, trade winds, sea breezes, the ITCZ and the November to April cyclone season dominate the questions.
Pressure and altimetry
QNH is the pressure reduced to sea level and gives elevation when set; QFE gives height above the aerodrome reference point; standard pressure 1013.25 hPa is used above the transition altitude. A falling QNH means deteriorating weather and a lower true altitude for the same indicated altitude.
Tropical weather
South-east trade winds prevail for much of the year. Sea breezes can reverse the coastal wind by day and night. The ITCZ brings deep convection and heavy rain. Tropical cyclones have a warm core, a clear eye, spiral bands and strongest winds around the eye wall; they bring storm surge, flooding and damaging winds.
Reports
METAR is an observed report; TAF is a forecast with a validity period in UTC. Cloud amounts: FEW is one to two oktas, SCT three to four, BKN five to seven, OVC eight. Fog is visibility below 1,000 m; mist is 1,000 m to less than 5,000 m.
Worked example
FIMP 121200Z 12012KT 9999 -SHRA SCT018 BKN035 27/24 Q1011. Decode: day 12 at 1200 UTC; wind 120 degrees true at 12 kt; visibility 10 km or more; light rain showers; scattered cloud at 1,800 ft, broken at 3,500 ft; temperature 27 C, dew point 24 C; QNH 1011 hPa. The 3 C spread indicates high humidity and a risk of further showers.
Traps
Confusing QNH and QFE; treating TAF times as local; reading BKN as scattered; forgetting that a cyclone's eye is not the end of the storm.