What is an outflow boundary?

Question

What is an outflow boundary?

Answer 1

From Wikipedia:

"An outflow boundary is a storm-scale or mesoscale boundary separating thunderstorm-cooled air (outflow) from the surrounding air; similar in effect to a cold front, with passage marked by a wind shift and usually a drop in temperature and a related pressure jump."

Answer 2

The outflow bourndary is basically the colder air usually higher found high in the atmosphere that has been brought all the way down or transported all the way to the surface by the convective nature of a thunderstorm.  The colder and denser air may spread out in all direction or maybe fan out in one main direction once it hit the surface.  If this occurs, the dense cold and drier air will spread rapidly away from the thunderstorm.  As this layer moves away, the outer edge of the boundary that seperates the colder and denser air from the warmer and less denser air is known as the outflow boundary or a smaller scale cold front.  Just like any cold front or surface boundary, if conditions are supportive, this outflow boundary can be the trigger or focus of the development of a line of showers or thunderstorms.