Squall Lines

A squall line is a line of thunderstorms that forms along or in front of a cold front. Pre-frontal squall lines may spawn severe thunderstorms with large hail and tornados. They are typically the largest type with a horizontal extent of 600 miles. Ordinary squall lines are usually shallower than pre-frontal squall lines and do not last as long. They typically feature less severe weather such as air mass thunderstorms.
Concept Mapping Toolkit
Insitute for Human and Machine Cognition
The University of West Florida