Extract from the weather journal

Kinds of weather

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Precipitation: When water vapour condenses and falls to earth, it is called precipitation. It can be rain, drizzle, snow, hail or showers. Rain is liquid water drops of variable size that have a uniform direction of fall. Drizzle is very small liquid droplets that may be sparse or thick. Unlike rain, drizzle droplets may fall in various directions, sometimes floating rather than falling. Snow is ice crystals, often interlocked, that form flakes. Hail is small pieces of hard ice that fall separately or frozen together into irregular lumps. Showers are associated with cumulus and cumulonimbus clouds and are in the form of rain, snow or hail. Showers generally begin and end abruptly, and may change intensity rapidly. They are usually brief (15 to 30 minutes), but may last longer.

Dew: A deposit of water droplets on objects at or near the ground. Produced by condensation of water vapour from the surrounding clear air.

Frost: Hoarfrost is a deposit of soft, white ice crystals formed when the temperature of the surface is below freezing point. It is produced by water vapour from the surrounding clear air. White dew is a deposit of white, frozen dew drops which forms when a deposit of dew is frozen when the temperature drops below freezing point.

Fog: A suspension of very small water droplets in the air that reduces visibility to less than 1000 metres.

Mist: A suspension of microscopic water droplets or wet hygroscopic particles in the air that reduces horizontal visibility. Mist usually has a greyish tinge.

Thunderstorm: A combination of thunder and lightning, with or without precipitation. When thunder is heard, the occasion should be counted as a thunderstorm, even if no lightning is seen.The intensity of a thunderstorm refers to the occurrence of thunder and not to precipitation. The intensifies are slight (isolated thunder), moderate (frequent thunder) and heavy (thunder almost continuous).