A line with solid triangles along one side, marking advancing cold air.
Also known as: Cold front, Line with triangles, Spikes on a weather map
Triangles along a line mark a cold front, and they point the way it is moving. The shape is not arbitrary — the sharp triangles were chosen against the warm front's rounded bumps so the two are distinguishable in monochrome.
Marks the leading edge of advancing cold air, with the triangles on the side the front is moving towards.
Contexts: Navigation
Is drawn with sharp triangles specifically so it remains distinguishable from a warm front's rounded bumps without colour.
Contexts: Navigation
Is coloured blue where colour is available, with the warm front in red — a redundancy that keeps the chart readable either way.
Contexts: Navigation
A curved line with solid triangles spaced along it, all on the same side and all pointing away from the line in the direction of travel.
Advancing cold air against advancing warm air.
The frontal symbol set.