Weather Fronts

Target #15- I can describe a weather front When two unlike air masses meet, density difference usually keep the air masses separate. Cool air masses are denser than warm air masses Their interaction is called a front Can be several hundred to several thousand kilometers long Initiates weather activity

Target #16- I can state how a front forms For a front to form one air mass must collide with another air mass Kind of front determined by how the masses move in relationship to each other Target #16- I can state how a front forms

Cold Front: occurs when a cold air mass overtakes a warm air mass Target #17- I can differentiate between the types of weather fronts that can form Cold Front: occurs when a cold air mass overtakes a warm air mass The cold air lifts the warm air mass If the warm air is moist, clouds will form The faster the front moves the stronger the storms Squall line: where thunderstorms form along a fast moving cold front

Warm Front: occurs when a warm air mass overtakes a cold air mass Less dense warm air rises over the cooler air Generally produces precipitation over a large area May cause violent weather

Stationary Front: occurs when two air masses meet, but neither displaces the other Either moves slowly or not at all Weather produced is similar to a warm front

Occluded Front: occurs when a fast-moving cold front overtakes a warm front and lifts the warm air off the ground completely Usually results in rain storms

Target #18- I can describe a mid-latitude cyclone Mid-latitude cyclones A wave forms at the boundary where cold polar air meets tropical air Usually occurs in the mid-latutides (half way between the equator and the poles) Hurricanes: Over oceans Tornadoes: Over land Illustrated by a counter-clockwise rotation of air Target #18- I can describe a mid-latitude cyclone

Target #19- I can state how a mid-latitude cyclone forms

Target #20- I can describe hurricanes a tropical storm that forms over a warm ocean has strong wind speeds of more than 120 km/h spirals toward its intense low pressure center Begins when warm, moist air over the ocean rises rapidly Winds increase toward the center (the eye) Causes a storm surge rising sea level Target #20- I can describe hurricanes

Target #21- I can summarize the impact a hurricane induced storm surge has on the environment Storm surges are frequently the most devastating element of a hurricane. As a hurricane’s winds spiral around and around the storm, they push water into a mound at the storm’s center. This mound of water becomes dangerous when the storm reaches land because it causes flooding along the coast. The water piles up, unable to escape anywhere but on land as the storm carries it landward. A hurricane will cause more storm surge in areas where the ocean floor slopes gradually. This causes major flooding.

Safir-Simpson Scale: a 5 category scale that groups hurricanes into groups by pressure, wind speed, and storm surge Target #22- I can identify what scale is used to measure the strength of a hurricane

Target #23- I can describe tornados Tornado: a destructive rotating column of air that has very high wind speeds and that is visible as a funnel-shaped cloud Forms when a thunderstorm meets high-altitude winds The winds cause the rising air to rotate Moves unpredictably Measured by the Fujita Scale

Twister