Overview
The Significant Weather Prognostic Charts (SIGWX) are forecasts for the predominant conditions at a given time. The Low-Level chart is a forecast of aviation weather hazards, primarily intended to be used as a guidance product for briefing the VFR pilot. The end product is an image with two panels. The panel on the left is a 12 hour forecast and the panel on the right is a 24 hour forecast from the issuance time based on the current NAM model.
The Low-Level SIGWX chart is issued every 6 hours beginning at 0000 Z.