Thursday, April 7, 2011

Clouds and Thunderstorms

                Something other than luck has to contribute to the large green landscape that Ireland is famous for. There is rain. Depending on the location, Ireland receives anywhere from 750 mm-2000 mm of rain per year. But how does rain form? What are the factors that go into a rain storm?
Before there can be rain, there needs to be clouds. Several different types of clouds result in the average of 150 rainy days that Ireland sees.  The most common type of cloud to be seen on a rainy day is a nimbostratus clouds.
A nimbostratus clouds like the ones above are considered low level clouds because they lie below 2000m. However if the clouds are larger, they can reach the med level range. Unlike many other clouds seen in the sky, nimbostratus clouds appear to be gray. The clouds are gray because they are carrying moisture, usually rain.
Nimbostratus clouds form when clouds from higher base height thicken and move lower.  Clouds like the altostratus above will do this.

Once these clouds are formed, then the rain can fall.
Through there is a lot of rain in Ireland, surprisingly there are few thunderstorms. But every now and then one will form.  Unstable air and moisture are the two main things needed for a thunderstorm to form.
The thunderstorm above was formed when the following happened:
1.       Warm air (in this case it could have been from a sea breeze) moves or is pushed up to higher levels.
2.       Downdrafts occur and rain begins to fall heavily.
3.       The rain will slow and the storm will dissipate.  
Sources Referenced and Pictures Taken from:
http://www.myguideireland.com/rainfall-in-ireland
Google images