Transcript Slide 1
An air mass is a large pool of air having similar temperature and moisture characteristics. An air mass occupies thousands of square miles of the Earth's surface. Air masses are created in a source region where they take on their characteristic temperature and moisture content.
The jet stream flows from west to east in wave-like patterns.
Which way will the wind blow in Louisiana? Why?
West to East, Jet Streams
Fronts are boundaries between contrasting masses of air.
Cold fronts are those where moving cold air slides under warm air The steep slope pushes the air ahead of it rapidly upwards and vertically developed clouds (cumulus) are produced along the front.
Warm Air Cold Air
Heavy Rain often occurs. Cold front Symbol
With greatly contrasting air masses on either side of the front, and potentially unstable conditions, violent weather can form. Towering cumulonimbus clouds are common along cold fronts producing intense downpours of rain lasting for a relatively short period of time. Tornadoes can form under the most extreme conditions ahead of an advancing cold front.
A warm front is where moving warm air pushes over cold air. As with a warm front, you experience a drop in the atmospheric pressure as the front approaches. The warm front slopes gently up into the troposphere that has a direct bearing on the kinds of clouds that are produced. As the warm air behind the front collides with the cooler air ahead, the warmer less dense air is forced to glide upward.
Warm Air
Light or moderate Rain often occurs. Warm front Symbol
Cool Air
Once the warm front passes your location you'll notice an increase in temperature and air pressure. Soon the stratus clouds of the warm front give way to broken and clearing skies. As the warm sector moves into your location you will notice an increase in the humidity of the air
Figure WS.4 Front Symbols
Air particles moving from areas of high pressure to areas of low pressure. Caused by uneven heating of the Earth.
Moving cold air slides under warm air.
COLD FRONT
Moving warm air pushes over cold air.
WARM FRONT
This symbol:
WARM FRONT