Abstract: The warning arrow of the present invention is in the nature of a frame to be temporarily mounted either directly to the body of the vehicle or to the underside of its trunk lid. In a preferred embodiment, the warning arrow is composed of a brightly-colored fabric material for high daytime visibility, and with the arrow being outlined by a plurality of light-reflective filaments for nighttime illumination by the beams of oncoming vehicular headlights. In accordance with the invention, a plurality of self-adhering fabric strips couple to the frame of the mount, either to magnetically secure the warning arrow to the body of the vehicle, or to extend it between its raised trunk lid and a point within its then opened trunk.