Outflow boundaries on radar

I'm watching a line of storms pass the DFW area this afternoon on DuPage's radar page and there are some marked outflow boundaries in two places south of the storms. My question is this-

What is the radar picking up? Is it just precipitation or will it see atmospheric particulates being swept up in the outflow? Earlier today an outflow from the Oklahoma storms earlier this morning passed my area where I work and I really didn't notice any precip, just a wind shift.
A good example of how this looks in reality can be seen here:



Watch northeastern Monroe County or northwestern Henry County as the boundary passes. You can see how the OFB helps storms pop up.

Another neat image can be found here:

In this case, enough development occurred along OFBs that they could be made out on the visible satellite imagery. (Look in srn MO, IL, IN)

Hey JP. I had the same question a couple months ago and found a good, english-language explanation here:


I often refer to this guy's site when I need a quick and dirty explanation of some meteorological term I don't fully undertand.
Thanks, Mike. That helps. I found Haby's Hints several days ago and I guess I hadn't gotten to that section yet. Dust and bugs, huh? The density change makes sense though. I was reviewing the last 12 hours of radar and satellite loops from north central Texas this evening and noticed the following:

1. The outflow boundary outlived the original storms by a wide margin. This morning's line of storms pretty much crapped out just south of the Metroplex but you can see the outflow boundary go well past San Antonio.

2. You can actually see those same outflow boundaries on satellite as a thin line of clouds moving southward. The cloud line dissipates well before San Antonio, though.

Does the size of the outflow boundary in terms of its width and persistence depend upon the scale of the convective system or whether supercells are present?