Download all day rain - Blair Community Schools

October 21, 2009
24-2 notes Fronts
I. Front- a boundary several km long between 2 different air
masses
A. Types of fronts
1. cold front- happens when a cold air mass overtakes a
warm one.
What happens? moist warm air rises, cools condenses, rain
cold front
2. Squall line - line of heavy storms that occur just ahead
in the warm moist air fast moving, intense storms. Large
cumulonimbus clouds form
B. Warm fronts - cold air retreats from an area. More gradual
slope. Cloud extend far ahead. high cirrus clouds, precip over a large
warm front
area
C. Stationary front a front of air masses that moves
either very slowly or not at all
D. Occluded front-a front that forms when a cold air mass
overtakes a warm air mass and lifts the warm air mass of the
ground and over another air mass
-all day rain
Fronts video
occualated link
October 21, 2009
E. midlatitude cyclone an area of low pressure that is
characterized by rotating wind that moves toward the
rising air of the central low-pressure region
Anticyclones the air of an anticyclone sinks and flows outward
from a center of high pressure.
The circulation of air is counter clockwise in the Northern
Hemisphere.
Anticyclones bring dry weather, because their sinking air does not
promote cloud formation.
October 21, 2009
SEVERE WEATHER
A. Thunderstorm a usually brief, heavy storm that consists
of rain, strong winds, lightning, and thunder
thunder link
Develop in 3 distinct stages
1. cumulus stage- warm moist air rises, air cools,
condenses see puffy clouds
2. mature stage- Rain, cumulonimbus clouds
3. dissipating stage-strong downdrafts cause the air to
stop rising.
B. Lightning- clouds discharge electricity
1. Electricity heats the air, the air rapidly expands and
lightning link
produces thunder.
2. Upper part of cloud usually (-) lower par (+) charge.
3. Sound travels 1 km in 3 sec
1 mile in 5 sec
1100ft in 1 sec
See lighting, how far is storm away when
you hear thunder in 7.5 seconds?
October 21, 2009
huricane pic
C. Hurricane
1. A severe storm that develops over warm tropical oceans and
Winds of more than 120 km/h spiral in toward the
intensely low-pressure storm center called the ________
2. Begins when warm, moist air over the ocean rises
rapidly.
3. When moisture in the rising warm air condenses, large
amounts of energy in the from of latent heat is released. This
heat increase the force of the rising air.
4. Most dangerous aspect of a hurricane is a rising sea level and
large waves, called a storm surge.
October 21, 2009
D Tornadoes
1.tornado a destructive, rotating column of air that has very high wind
speeds
A. small, most violent, and shortest-lived severe storm
B. How formed?
A tornado forms when a thunderstorm meets high-altitude
horizontal winds. These winds cause the rising air in the
thunderstorm to rotate.A storm cloud may develop a narrow, funnelshaped rapidly spinning extension that reaches downward and
may or may not touch the ground.
pic
Winds may reach speeds of more than 400 km/h.
web link
October 21, 2009
October 21, 2009
back
October 21, 2009
October 21, 2009
October 21, 2009
First Page
October 21, 2009
First Page
October 21, 2009
back
October 21, 2009
Back
October 21, 2009
back