'Lines' That Form Near Storms

[James K]

See attached image.
The lineup of small storms you see was moving southeast-ish,
But note south of them, there's a 'line' (2 actually) that was moving faster than the storms....

I see these show up on occasion (not always in front of storms, and usually only a single). Is my assumption correct, that that is simply an outflow boundary?

 

[Dan Robinson]

Yes, those are outflows from earlier storms. If you look at a longer loop, you'll probably see the bigger storm complex upstream that created it. Sometimes these are a stationary frontal boundaries that get a push from storms that form on the cold side of them. In either case, the boundary acts like a cold front once it is on the move (it essentially is one, technically speaking), which can trigger new storms along and behind it, which keeps it moving.

 

[James K]

Thanks Dan. Confirmed what I thought

In this case those storms might have been what created it...they were in the dieing-out state when I captured the screenshot.


I did once see a couple new storms fire off one of those boundaries (they grew fast too)...but that was also a day that had more moisture & higher CAPE to work with.