Atmospheric Phenomena

11:38am Monday 17th March 2008

On many occasions if you are looking skyward, we can witness beautiful Atmospheric Phenomena, from unusual shapes, lights to colours and cloud formations. Many are not seen as we go about our busy daily routines. I find the most interesting atmospheric phenomena occurs around the sunrise and sunset times of the day. Often these weather events are caused by reflection or refraction of light through water or ice crystal within the clouds, also light passing through layers of air with different densities. Vapour trails or condensation trails made by aircraft flying at high levels. In very cold upper level air, the water vapour in aircraft engine exhaust change into ice crystals before it has time to disperse, so it makes a line of cloud across the sky. Crepuscular rays when the sun is lower in the sky than the clouds, the light passes through water droplets, smoke or dust particles and appear as bands of light sometimes referred to as the sun drawing water, or witches fingers. Haloes around the sun or moon is caused by refraction of light through ice crystal cloud.

Next week........Dew and Water Vapour.The answer to last weeks question: Cooler and Moist.This week's question: Haloes are caused by:A/ Reflection of Light.B/ Refraction of Light.Best of Luck. Glossary:

Blizzard: A wind storm in which large amounts of snow are blown into the air from the surface and carried at high speed. These conditions cause huge drifts of snow and often causes white out conditions when visibility is reduced to zero.Weather for coming week Monday 17th March-Friday 21st March.High pressure influencing our weather, lower towards the end of week.Fine weather conditions with some overnight frost during the first half of week, mixed later as low pressure takes command. Often windy especially mid-week onwards.Maximum temperature 8-10c 46-50f.Minimum temperature Minus 2c to plus 6c 28-43f.The below freezing night temperatures mainly early on in the week.Last Week's Observations (Monday-Friday)Highest day temperature..............14.5c 59f on Tuesday 11th March.Lowest night temperature..............3.5c 39f on Thursday 13th March.Wettest day................................37.5 mm on Saturday 15th March.

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