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TOPIC: Lightning Conditions / Clearances

Lightning Conditions / Clearances 11 months 3 weeks ago #882

  • andrewhegg
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Hi. Does anyone out there know of any current guidance material describing the environmental/weather conditions most conducive to the formation of lightning? From memory, meteorological advice was that lighting strikes were most likely if precipitation is falling through the -10°C isotherm, however not sure if this information remains extant.

A cursory review of the literature available, suggests that the majority of lightning strikes occur at intermediate altitudes (5000 to 15000 ft), inside cloud and/or in the presence of rain at or near freezing temperatures and that the probability reduces significantly above 20000 ft. Thanks.

Lightning Conditions / Clearances 11 months 2 weeks ago #883

  • wahoo91
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From AF Handbook 11-203 :

13.12.4. Research aircraft have shown that penetration of the upper reaches of a thunderstorm (35-40,000 feet with temperatures less than -40oC) provides one of the greatest potentials for strikes and discharges. The majority of Air Force and commercial airline incidents, however, occur at lower altitudes in non-thunderstorm clouds and in areas outside of active thunderstorm cells. Aircraft probably trigger strikes and discharges of this type since they would not occur naturally without the aircraft. In most of these cases the aircraft operates in one or more of the following conditions:
13.12.4.1. Within 8oC of the freezing level.
13.12.4.2. Within 5,000 feet of the freezing level.
13.12.4.3. In light precipitation (including snow).
13.12.4.4. In clouds (including debris clouds).
13.12.4.5. In light or negligible turbulence.
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