Assessing Weather Threat Levels

Identification and investigation of potential threats are the first steps in the process, followed by assessing the level of threat indicated by precipitation returns. This involves interpreting the weather radar display and other available information to determine if there is an actual threat, and then determining the best course of action to mitigate that threat.

Radar returns with steep gradients (Fig. 32, left side) indicate intense precipitation and very strong turbulence. Squall lines (Fig. 32, center) are generally frontal in nature and can extend for hundreds of miles. The areas between cells may look clear of weather, however thunderstorms build quickly, and strong turbulence is likely in those areas. Squall lines should not be penetrated. Returns showing scalloped edges (Fig. 32, right side) indicate intense precipitation and likely hail, as well as strong turbulence. Hooked fingers (Fig. 32, right side) also represent areas of strong turbulence, and possible tornado formation.

KEY POINT: Airborne weather radar is used to avoid adverse weather, and never for penetration of areas of hazardous weather.

The “Blind Alley” effect (Fig. 33) occurs when proceeding along a course based on what appears to be an adequate opening between cells, only to find that intense precipitation extends beyond your current range of view. Adjusting the range outwards may show additional cells beyond your current display setting.

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