In the area of higher pressure the air molecules are
closer together than in areas of lower pressure. Warm air, which is
lighter, cause low pressure. Air that is warmed exerts less
pressure on the ground creating a low pressure region. Cold air when it
is over the oceans will actually depress the sea level in that area.
Warm air will elevate the sea level.
Cold air is denser and heavier and pushes the
warmer, lighter air upward. Depending on how the warmer air is pushed
will depend upon how big the "fight" will be. Where these two
air masses meet is called a "front." How these
different fronts meet cause weather patterns to change. Remember there
are many temperature variations of "cold" air and
"warm" air, resulting in many weather types.
Moving from low to high pressure