High/Low Pressure Activity Questions

Moving in the direction towards the center of a High, the surface atmospheric pressure _________________. When moving towards the center of a Low, the surface atmospheric pressure _________________.

• increases, decreases

• increases, increases

• decreases, increases

• decreases, decreases

Which of the following best describes the surface wind circulation around the center of a High pressure system (as seen from above)?

• counterclockwise and spiraling outward

• counterclockwise and spiraling inward

• clockwise and spiraling outward

• clockwise and spiraling inward

Which of the following best describes the surface wind circulation around the center of a Low pressure system (as seen from above)?

• counterclockwise and spiraling outward

• counterclockwise and spiraling inward

• clockwise and spiraling outward

• clockwise and spiraling inward

In a High pressure system, air flows

• downward and outward in a clockwise spiral.

• downward and inward in a counter-clockwise spiral.

• upward and outward in a clockwise spiral.

• upward and inward in a counter-clockwise spiral

In a Low pressure system, air flows

• downward and outward in a clockwise spiral

• downward and inward in a counter-clockwise spiral.

• upward and outward in a clockwise spiral

• upward and inward in a counter-clockwise spiral.

The weather associated with a Low can be significantly different than that of a High. The differing vertical motions account for some of these differences. Vertical motions lead to temperature changes in the rising or sinking air. The temperature changes occur because air warms when it is compressed and cools when it expands. In the open atmosphere, air pressure is less at increasing altitudes. Consequently, air expands and cools when ___________. Air is compressed and warms when ___________.

• ascending, descending

• descending, ascending

• ascending, ascending

• descending, descending

In a Low, air generally exhibits ascending motion. The rising air experiences ___________ atmospheric pressure. The ascending air ___________ and its temperature ___________ .

• increasing, expands, decreases

• decreasing, expands, decreases

• decreasing, is compressed, decreases

• increasing, is compressed, increases

In a High, air displays descending motion. The sinking air experiences ___________ atmospheric pressure. Consequently, the descending air ___________ and its temperature ___________ .

• decreasing, expands, increases

• increasing, expands, decreases

• increasing, is compressed, increases

• decreasing, is compressed, decreases

Most clouds form by the cooling of air. Air, if sufficiently cooled, will become saturated with water vapor. Continued cooling will result in condensation, cloud formation, and possible precipitation. The vertical motion in a __________ often leads to cloud formation.

• low

• high

Warming causes clouds to evaporate. Cloudy air is saturated with water vapor. With sufficient warming, it will become unsaturated and existing cloud particles (water droplets or ice crystals) will evaporate. The vertical motions in a ____________ produce warming, promote cloud dissipation, and lead to clear skies.

• high

• low