warm air rises cold air goes down sinks
the warm air rises up and moves over the cold air that is already there.
It pushes the warm air above the cold air
Warm air moves over cold air and replaces it.
I pushes the warm air upwards.
cold front
A cold front.
I. The cold air mass is pushed underneath the warm air mass.
I. The cold air mass is pushed underneath the warm air mass.
Yes
A warm front forms.
A warm front forms.
A warm front forms.