Page 311 - PPL-engelsk 2025

Meteorology

3.8.6.1 Summer warm front

In summer, the warm air mass is often humid and can bring rain and

thunderstorms when it meets the colder air. This front generally leads to high

humidity and can result in hot and unstable weather.

3.8.6.2 Winter warm front

In winter, the warm air mass is often dry and can lead to milder, but also foggy

weather, when it moves over a colder surface. Rain may occur, but it is more

likely to be snow, which later melts.

Here you see a sketch that

shows the precipitation

situation during the passage

of a winter warm front.

It may start with snow. The snow falls through the cold air in front of the front.

The snow is often formed from small cloud droplets and is called snow grains

when the frozen droplets hit the ground. Larger droplets freeze as they

approach the ground into ice pellets. In the intermediate stage, snow grains are

freezing drizzle, and ice pellets are freezing rain.

Flying at these altitudes presents a high risk of severe icing.

It is in the winter warm front that the risk of severe icing is greatest! It is also

here that we experience ice accretion.

When the ground temperature is above 0°C, there can still be a risk of icing at

higher altitudes. As the warm air moves in, the weather changes to rain, light

rain, and warmer conditions.

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Flight Theory PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 311