Definition
An organized band of thunderstorms arranged along a relatively narrow line, often extending for tens or hundreds of miles. In Convective SIGMET terms, a line of thunderstorms is reported when thunderstorms are aligned such that any required gap between cells is small enough that the line behaves as a continuous hazard, typically with the storms producing severe weather along its length.
Plain English
A long row of thunderstorms standing close enough together that pilots have to treat them as one big wall of weather rather than separate storms you could weave between.
Context Anchor
Seen in Convective SIGMET discussions and other inflight weather advisories when widespread thunderstorm activity may affect a route of flight.
Why Pilots Care
These lines create an extended hazard zone that is difficult to circumnavigate and can produce severe turbulence, hail, and wind shear across hundreds of miles.
Analogy
Think of it like a moving fence of storms. The fence may not be solid in every spot, but it is still a major barrier across your path.
Grounding Statement
Imagine a solid wall of storms stretching across your route that you cannot safely fly through or over.
Intuition Check
Do not assume “line” means a perfectly straight, unbroken row. In this weather-advisory context, it means a long organized band of thunderstorms that meets specific length and coverage criteria.
Example Sentence 1
The Convective SIGMET reported a line of thunderstorms moving east at 30 knots, so we delayed departure until it passed the field.
Example Sentence 2
Our route required a wide deviation south to stay clear of the lines of thunderstorms reported in the SIGMET.