1. Storm clouds

2. Cumulonimbus clouds

3. Cold rain process

4. Saturated vapour pressure

5. Ice crystals grow at the expense of supercooled water droplets. Air is saturated over ice. Air is not saturated over water. Water evaporates from the supercooled droplets - the droplets disappear The water vapour deposits on the ice crystals - the crystals grow

6. Falling ice particles

7. Development of cumulonimbus

8. Multi-cell storm

9. Thunder and Lightening

10. Lightening Forked lightening from cloud, showing stepped leaders and main return stroke Lightening originating from a tower on the ground, note forks go upwards.

11. Time resolved lightening formation

12. Supercell thunderstorm

13. Contrails At high altitude ~10 km temperature very low, condensation aided by exhaust particulates and vortices.

14. Nacrecous clouds Nacrecous clouds are 15 - 25 km high, in the stratosphere well above tropospheric clouds, and occur mostly in polar regions and in winter at high latitudes. Seen after dusk. Also called mother-of-pearl or polar stratospheric clouds.

15. Noctilucent clouds Noctilucent clouds are thought to be composed of small ice- coated particles; their precise nature remains a mystery. They form at very high altitudes ~ 82 km - and are a quite separate phenomenon from normal tropospheric clouds.