Fronts are given their name because they are the battle zone between two different air masses. They can be identified by any of the following characteristics: a sharp temperature gradient, a sharp moisture gradient, or a sharp change in wind direction. Fronts are categorized according to their net movement. For example, when a warm air mass advances on a cooler air mass, the boundary between them is called a warm front. Clouds and light to moderate precipitation usually form ahead of a warm front. When a cold air mass advances on a warmer air mass, the boundary is called a cold front. Since surface friction creates a much steeper slope in a cold front than in a warm front, air masses are lifted more rapidly and clouds grow to greater vertical extent. A narrow but heavy band of precipitation is usually seen along a cold front.

Practice Drawing Fronts and Highs/Lows

(Copyright 1999, University of Wisconsin-Madison/SSEC)

Across the top of the drawing region are a series of buttons:

• Erase Last Line - This button erases the lastest line you've drawn. Hitting this button twice will erase the last two lines (or letters) you drew.
• Objects - Use this to select the type of front or pressure center you want to draw. Just select one of these and then 'drag' the mouse on the image below (that is, press and hold the mouse button while moving the pointer).