Weather patterns Ch 5 Lesson 2

Pressure systems High Pressure Low Pressure High pressure in the center Brings sunny skies and fair weather Low Pressure Low pressure in the center. Brings cloudy skies, and sometimes precipitation (like rain or snow)

Air Masses

Fronts: a front is a boundary between 2 air masses. Cold Front: cold air mass moves toward a warmer air mass. The cold air pushes underneath the warm air mass. Effects: wind becomes gusty and changes direction and there is severe weather Warm fronts: warmer air mass moves toward colder, dense air. The warm air rises and glides above the cold air mass. Effects: brings warmer temperatures and causes the wind to shift.

Effects: usually bring precipitation. Occluded front: Stationary front: These form when a fast moving cold front catches up with a slow-moving warm front. Effects: usually bring precipitation. These stall out for several days with warm air on one side, and cold air on the other Effects: cloudy skies and light rain

Severe weather

Thunderstorm Thunderstorms are also known as electrical storms. Have warm temperatures, moisture, and rising air. Supplied by a low- pressure system

Tornado A tornado is a violent, whirling column of air in contact with the ground. These are measured on the Enhanced Fujita Scale. Tornado Alley is from Nebraska to Texas.

Is an intense tropical storm with winds greater than 119 km/h These form over warm ocean water. They have a circular shape with intense, swirling winds. Damage comes from strong winds and flooding from storm surge and heavy rains. Hurricane

A violent winter storm identified by freezing temperatures, strong winds, and blowing snow. Blowing snow reduces visibility and low temperatures can cause frostbite and hypothermia. Blizzard