| A | B |
|---|
| air mass | Huge body of air having relatively uniform temperature, humidity covering a very large area |
| cold front | Advancing edge of a cold air mass |
| continental air mass | Air mass that forms over land |
| cyclone | Hurricane in the region of the Indian Ocean; a low pressure area |
| doldrums | Permanent low-pressure area along the equator caused by the rising of warm air |
| forked lightning | Lightning formed when a stepped leader branches on the way to the ground |
| front | Ice crystals formed on a surface when the cooler surface cools a nearby film of air to a below freezing dew point |
| heat lightning | Flashes of lightnining from clouds too far awayfor the thunder to be heard |
| horse latitudes | Permanent high pressure areas that are caused by descending cold air and result in no horizontal wind |
| hurricane | Giant windstorms that form over the tropical oceans near the equator |
| land breeze | Breeze that blows from shore to sea, usually during the night |
| lightning | Electrical discharge that occurs either between clouds or between a cloud and the ground |
| monsoon | A wind system that reverses directions periodically and thus brings periodic changes in climate over a large region |
| occluded front | Arrangement when a cool air mass and a cold air mass trap a warm air mass between them; warm air mass rises over the other air masses and loses all contact with the ground |
| polar air mass | Air mass that form over cold areas |
| prevailing westerlies | Consisten winds blowing towards the poles from 30 degrees latitude |
| return stroke | Lightning discharge from the ground to the cloud |
| sea breeze | Breeze that blows from the sea to the shore, usually during the day |
| source region | Region with uniform temperature and humidity over which air masses form |
| squall line | Line of violent thunderstorms that sometimes accompanies an advancing cold front |
| stationary front | zone of contact between two dissimilar air masses, neither of which is displacing the other, and usually resulting in no weather change |
| stepped leader | Barely visible lightning discharge that jumps in a series of steps from the cloud to the ground |
| storm swell | First signs of an approaching hurricane |
| subpolar low | Low pressure area formed at 60 degrees N when the prevailing westerlies rise above the polar easterlies |
| thunderhead | Towering cumulonimbus cloud that rises rapidly to an altitude of about 7,600 m resulting in heavy showers, lightning and thunder |
| tornado | Narrow, funnel shapted cyclonic windstorm extending down from a cumulonimbus cloud |
| trade winds | Consistent winds inthe subtropics and tropics once used by ships sailing from Europe to the New World |
| tropical air mass | Air mass that forms over warm areas |
| typhoon | Name given to hurricanes that occur in the Pacific region |
| warm air mass | Air mass that is warmer than the surface over which it moves |
