Fronts and severe weatherlecture 22.3

Fronts

• A front is where masses of air collide.

Stationary front

• Cold and warm air meet

• They move side by side along the front

Warm front

• Warm air moves up over cold • Air cools, forms clouds (cirrus, cumulus)• Later, nimbostratus and steady rain

Cold front

• Cold air moves in under warmer air• Warmer air is pushed up quickly• Thunderstorms, maybe tornadoes

Lightning

• Electrical charges in a cloud can produce a spark.

• Thunder is the shockwave it creates

Lightning storms

Tornadoes

Funnels of high-speed wind

Occur in spring, early summer when warm, moist air from Gulf meets cool, dry air from Canada

Tornadoes, cont’d

Hurricanes

• Begin over warm oceans, in late summer

• Energy is released from condensing clouds

• Extreme low pressure in the “eye”

Hurricane damage