Updated: Aug 10, 2022
When thunderstorms develop and evolve, their "exhaust" is cold dense air flowing down through the storm, striking the ground and moving outward away from the storm. To better understand this, imagine pouring pancake batter onto a griddle. The edge of that pancake is the outflow boundary which is essentially a gust front of sorts. Are they dangerous if you encountered one of these in flight? Not usually. They are more robust the closer you are to the convection that produced them...especially flying down low. The are ground-hugging events that normally are no more than 6,000 to 8,000 feet deep.
Enjoy this loop of a nearly perfect outflow boundary emanating from convection that erupted over the Fort Worth WSR-88D Doppler radar site. If you were wondering, these outflow boundaries (and gust fronts) are filtered out of the radar depiction you will get with SiriusXM and FIS-B.
Most pilots are weatherwise, but some are otherwise™
Dr. Scott Dennstaedt
Weather Systems Engineer
CFI & former NWS research meteorologist