Squall line
Also called squall, line of storms, instability line
Weather-map symbol. A chart convention, not a forecast icon.
Weather-map symbolsSquall line meaning
A squall line is a line of thunderstorms on a weather map. There is no single ornament, in the NOAA lesson used here, the way a cold front has triangles.
At a glance
- System
- Synoptic chart convention
- Used for
- A line of storms
- Not the same as
- A cold front, or a windy icon
A line of thunderstorms. The ticks on this drawing are a reading aid, not a required ornament.
The name. A line of storms. Publishers do not share one ornament the way cold fronts share triangles.
Where it comes from
JetStream discusses squall lines with severe wind, and it does not fix a unique symbol in the way it fixes triangles, half-moons, and the letters H and L. WWIS lists “squall” as a forecast-icon label, which is a different system again: a word for wind, not a map boundary. The short ticks on this drawing are a reading aid so the page can be told from a front. They are not a claim that every chart service draws those ticks.
The line drawing is original to this cabinet. It is not an agency logo, a vendor icon, or the emoji for the same idea.
Weather
What it means
Storms arranged in a line, often ahead of a cold front, sometimes shown as a line the map’s legend must explain. If the legend is missing, do not invent the ticks as law. Thunderstorm icons in a forecast are point summaries. A squall line is the arrangement of the storms.
Questions
What is the symbol for a squall line?
Maps do not share one ornament in the JetStream lesson the way fronts share triangles and half-moons. This page uses ticks only as a reading aid. Trust the legend on the map in front of you.
Is a squall the same as a cold front?
No. The front is the air-mass boundary. The squall line is a line of thunderstorms, often ahead of that boundary.
Near this
- Cold frontA line with triangles in the direction of motion. Cold air is advancing. The color is a publisher’s aid.
- ThunderstormA forecast icon for thunder and lightning. Not a decorative bolt, and not ordinary rain.
- TroughElongated lower pressure and a wind shift. Not a front. The dash is a common habit, not a second alphabet.
- WindA forecast icon for expected wind. Not a wind barb, and not the wind-face character.
Sources
Named when the entry depends on a text, a date, or a standard. Catalog numbers are not invented.
Your margin
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symbol.wiki, edited as Sigilla. Last reviewed 18 October 2026. A reading of public tradition, not a ruling.