| A | B |
|---|
| Air mass | A huge body of air that has similar temperature, humidity, and air pressure throughout |
| Tropical | Warm air masses with low pressure that form in the tropics |
| Maritime | Humid air masses that form over oceans |
| Polar | Cold air masses with high pressure that form north of 50° north and south of 50° south |
| Continental | Dry air masses that form over the continents |
| Maritime Tropical | Warm wet air masses bringing low pressure and rain |
| Maritime Polar | Cold wet air masses bringing high pressure and snow |
| Continental Tropical | Warm dry air masses bringing low pressure and warm, dry air |
| Continental Polar | Cold dry air masses bringing high pressure and cold, dry air |
| Prevailing westerlies | Major wind belts in the United States. These wind belts are responsible for pushing air masses from the west to the east |
| Front | The area where air masses collide (meet and don’t mix) is called a front, often the location of severe weather |
| Cold front | Dense cold air masses that move quickly and cause abrupt weather changes and storms |
| Warm front | Slower moving warm air masses that slide over cold air masses |
| Stationary front | The boundary zone between a warm air mass and a cold air mass formed when neither can force the other to move. Characterized by many days of clouds and precipitation. |
| Occluded front | A complex weather situation where two cold fronts surround a warm front, cutting it off from the ground (occluded) and forcing the warm air mass upwards. Rain and clouds develop. |
| Cyclone | Low pressure centers of wet air with counter clock-wise wind circulation with inward spiraling winds. (Causing warm wet weather: Hurricanes or tropical storms) Counterclockwise rotation occurs in the northern hemisphere because of the coriolis effect. |
| Anticyclone | High pressure centers of dry air with clockwise rotation of outward spiraling arms, causing dry, clear weather. |
| Storm | A violent disturbance in the atmosphere |
| Thunderstorm | Heavy rainstorms accompanied by thunder and lightning that form within cumulonimbus clouds. |
| Tornado | A rapidly whirling, funnel shaped cloud that reaches down from a storm cloud. When formed over water, a water spout is produced |
| Hurricane | A low pressure, cyclonic storm with enormous rainfall and winds in excess of 119 km/h |
| Lightning | A sudden spark, or energy discharge that happens between clouds or cloud to land. |
| Lake-effect snow | When a cold, dry air mass moves of into the humid (warmer) air above a lake, it picks up the moisture, and deposits it after rising and cooling again. (Usually within 40 km) |
| Storm surge | A dome of water that sweeps over the coastal areas when a hurricane lands |
| Evacuate | Move away from danger |
| Flash flood | A sudden, violent flood that occurs within a few hours or minutes of a rainstorm |
| Meterologist | Scientists who study the causes of weather and try to predict it. |
| Butterfly effect | A small change in the weather now can have major effect on the weather in a few days |
| Isobar | Lines on a weather map that run along areas of the same pressure |
| Isotherm | Lines on a weather map that run along areas of the same temperature |
