Snow grains.

snow pellets

Drifting snow.

Blowing snow

Cloud cover has NO effect on the amount of the Sun's radiated heat arriving at the Earth's surface.

The Earth only radiates heat into space between sunset and sunrise.

The Earth is heated by short-wave radiation from the Sun, but cooled by its own long-wave radiation into space.

The Earth is heated by long-wave radiation from the Sun, but cooled by its own short-wave radiation into space.

back and decrease.

veer and decrease.

back and increase.

veer and increase.

southerly.

northerly.

easterly.

westerly.

When temperature decreases, the relative humidity and the dew point remain constant.

When temperature increases, the relative humidity increases, and the dew point decreases.

When temperature increases, the relative humidity decreases, and the dew point remains constant.

When temperature decreases, the relative humidity decreases, and the dew point increases.

coming from an area of high pressure, the aircraft is flying towards a low pressure area.

Coming from an area of low pressure, the aircraft is flying towards a high pressure area.

The true altitude is increasing steadily.

The flight is conducted parallel to the isohypses.

Stratocumulus, altostratus, cirrus.

Cirrocumulus, altostratus, stratocumulus.

Cirrostratus, altostratus, stratus.

Cirrocumulus, altocumulus, cumulus.

clouds containing only ice crystals.

cirro-type clouds.

convective clouds.

stratified clouds.

As pressure decreases the true altitude decreases.

As pressure increases the true altitude decreases.

At a constant flight level, variations in pressure do NOT affect the true altitude.

As pressure decreases the flight level will increase and true altitude will increase.

The pressure gradient force moves the air towards the low pressure, but surface friction starts to pull the air anticlockwise, eventually causing the wind to blow parallel to the isobars with the low pressure positioned downstream to the left.

An air parcel initially at rest will move from high pressure to low pressure because of the coriolis force, but asthe air moves it is deflected to the right and is eventually balanced by the pressure aradient force.

As the air starts to move and is accelerated by the pressure gradient force, it is increasingly deflected to theriaht by the coriolis force until both forces are balanced and opposite to each other.

As a surface pressure difference begins, air will start to move towards the lower pressure. As the wind gains speed the pressure gradient force deflection increases to the right until it equals the coriolis force and the