Meteorology: Thunderstorms - Flight Techniques 1953 US Navy Pilot Training Film MN-7409-B (Patreon)

more at http://quickfound.net/

Produced for the US Navy by Bray Studios.

Originally a public domain film from the US Navy, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.

The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).

https://www.weather.gov/media/publications/front/11jul-front.pdf

Thunderstorm Formation

and Aviation Hazards

By Ken Harding, Meteorologist in Charge, WFO Topeka, KS

Thunderstorms are one of the most beautiful atmospheric phenomenon. As a pilot, however, thunderstorms are one of the most hazardous conditions you can encounter. All thunderstorms can produce severe turbulence, low level wind shear, low ceilings and visibilities, hail and lightning. Each of these hazards can be difficult to cope with; if all these conditions arrive at once, it can be disastrous. Understanding basic thunderstorm formation and structure can help you make safe decisions.

Thunderstorms are formed by a process called convection, defined as the transport of heat energy. Because the atmosphere is heated unevenly, an imbalance can occur which thunderstorms attempt to correct. Three things are needed for convection to be a significant hazard to flight safety: moisture, lift and instability.

 Moisture—Sufficient moisture must be present for clouds to form. Although convection occurs in the atmosphere without visible clouds, think thermals on a warm afternoon, moisture not only is the source of a visible cloud, but also fuels the convection to continue. As the warm air rises, it cools, and the water vapor in the air condenses into cloud droplets. The condensation releases heat, allowing the rising air to stay buoyant and continue to move upward.

Lift—There are many ways for air to be lifted in the atmosphere. Convection, or buoyancy, is one method. Other meteorological methods include fronts, low pressure systems, interactions between thunderstorms, and interactions between the jet stream and the surface weather systems. Air also can be lifted by mechanical lift, such as when it is forced up and over a mountain range. Regardless of how the air is lifted, if the lift is enough to make the air warmer than the surrounding air, convection can continue...

Three Stages of Thunderstorms

Towering Cumulus Stage: This is the stage of a thunderstorm once convection has begun and a cloud is visible. These building clouds are made entirely of liquid water. This stage is characterized by upward motion throughout the entire cloud. Aviation hazards from this stage include turbulence and icing. Even though the cloud is composed of all liquid, some of the liquid is “supercooled,” in other words, liquid water can exist at temperatures below the normal freezing point.

Mature Stage: This stage is characterized by the production of precipitation. Both updrafts and downdrafts are present. Lightning is being produced. The mature thunderstorm contains water, supercooled water and ice.

Dissipating Stage: During this final stage, the updraft has ceased and the storm is dominated by downdrafts. Precipitation may still occur, but will decrease with time as moisture is depleted. This dissipating thunderstorm contains mostly ice. You can visually estimate the potential for convection to continue by looking at the texture of the thunderstorms. If the cumulus tops are crisp and well defined—often looking like a cauliflower, the storm will continue to grow...