2.  Weather = The state of the atmosphere at a given time and place, with respect to variables such as temperature, moisture, wind velocity, and barometric pressure, etc.  Meteorology = The study of weather

3. Weather  Cloud  Wind  Temperature  Pressure  Significant phenomena

4. Cloud  = A mass of water droplets and/or ice crystals  Cloud base = the lowest height of the cloud cover  Cloud cover = the amount of cloud which can be seen in the sky  Types

5. Types of clouds:  A high-level, stable layer clouds: cirrocumulus, cirostratus (thin), cirrus (long and thin)  A medium-level stable layer clouds: altocumulus, altostratus,  A low-level stable layer clouds: stratus, stratocumulus, nimbostratus (grey, dark, stable with continuous rain or snowfall)

6. Types of clouds  Significant clouds: cumulonimbus Cb – large, dense, unstable heap cloud with a lot of vertical height and which can develop into thunderstorms  : cumulus - large, unstable heap cloud with considerable vertical extent

7. Wind  = The movement of air between areas of different atmospheric pressure  Wind speed - knots, Direction  Gust = A sudden, temporary increase of wind speed of at least 10 knots  Wind shear = a sudden change in wind direction and/or speed over a short distance  Head-, tail-, crosswind

8. Temperature  Celsius degree  Dewpoint = The temperature to which a volume of air must be cooled at constant pressure for saturation to occur

9. Pressure  QNH = Altimeter sub−scale setting to obtain elevation when on the ground, measured to mean sea level,  QFE = -/- to reference level of airdrome,  Standard atmospheric pressure  hPa, Torr,

10. Aerodrome weather  CAVOK  SKC  FEW 1 – 2/8  SCT 3 – 4/8  BKN 5 – 7/8 (significant clouds for VFR)  OVC 8/8

11. Significant phenomena:  SN (BLSN), DZ, DU, PO, DS,  FG (BCFG, FZFG), GR, HZ, PL,  IC, ICE, RA (FZRA, RERA), SA, SS, MIFG, SH, SIGWX, FU,  SG, GS, SQ, TS, TC, UP, VA,  Lightning  HVY TSGRRA

12. Intensity of phenomena  Precipitation (e.g., rain, snow, hail): - light - moderate - heavy  Wind shear: - moderate - strong  Other phenomena (e.g., turbulence, icing): - light - moderate - severe

13. Colour code = Colour system used to describe weather at airfield (visibility, cloud base)  BLU+, BLU, WHT, GRN, YLO, AMB, RED, BLACK

14. Reports  METAR – actual report – visibility, weather, cloud, wind, temp., QNH, dew point,…  TAF – weather forecast, expectation for 24 h period,  SPECI – extra report given due to significant and sudden changes,  SNOWTAM – about snow and snow clearing at an airfield (DLTZ).

15. Conditions:  VMC – symbol used for visual meteorological conditions  IMC – symbol used for Instrument meteorological conditions Airspace classC-D-EG Flight visibility 8 km AT and ABOVE FL 100 5 km BELLOW FL 100 5 km Clear of clouds and in sight of the surface Distance from clouds 1500 m horizontally 300 m (1000 ft) vertically

16. Sources  AIP – GEN 2.2, ENR 1  MODULE 1 AIRCRAFT AND AIRFIELD TERMINOLOGY  L – PHRASEOLOGY  Own notes: MIL AIC – C01/06 15 FEB 06 SPECI criteria colour code table  Internet - Google

17. Questions ?