Research and Evaluation: Weather Phenomenon

Essay by eshlaUniversity, Bachelor'sA, June 2007

download word file, 3 pages 3.0

The weatherman on the National Weather Channel is predicting 12 inches of snow for Grand Rapids, Michigan. He said it is going to be cold and the residents should be prepared for a long day. The “lake effect” is moving in and is expected to move south east causing heavy snowfall for the surrounding areas. As he is doing his weather report, but gets to Pennsylvania. In his report, he is predicting that Middletown, Pennsylvania will see a dusting of snow, one inch at the most.

What is the weather phenomenon known as the “lake effect” and why does it effect Grand Rapids, Michigan differently than it effect Middletown, Pennsylvania? Lake effect snow is caused by the temperature contrast between cold air moving over warm water. The bottom layer of air is heated from below by the water causing moisture to evaporate into the air. Knowing that warm air is lighter and less dense than cold air, we know that the heated air rises, then cools eventually forming clouds.

The wind pushes the clouds over the land. As this happens, friction with the ground, which is greater than the friction between the lake’s water and the moving air, slows the winds. This causes the air that is carrying the clouds to “pile up”. Meteorologists refer to this as convergence. Occasionally lake effect snow clouds can develop enough up and down motion to create “thundersnow”. Thundersnow is a snow storm with thunder and lightening. (Williams, ND) When enough moisture has condensed out of the air, snow begins to fall. The greater the temperature difference between the cold air and the warm water, the larger the snow fall. (Ask Yahoo website) When lake effect snow squalls are well developed, there could be less than 12 hours between storm systems. (islandnet website)...