Air mass movement reference pictures ppPresentation Transcript
Moving Air Masses
An air mass is a vast pool of air having similar temperature and moisture characteristics over its horizontal extent. An air mass occupies thousands of square miles of the Earth's surface. Air masses are born 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. west east
Meteorologists agree that jet streams may act as a barrier between cold air in the north and warm air in the south. During their meandering, the streams appear to allow some cold air to flow southward and warm air to flow northward. These flows undoubtedly affect the formation of cold and warm air masses.
Which best describes the direction that high and low pressure area Move across the United States? Why? West to East
Fronts are boundaries between contrasting masses of air.
Cold Fronts Cold fronts are those where moving cold air slides under warm air. Friction slows the advancing cold air causing a steep slope to the front. 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.
Warm Fronts 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 Cool Air Light or moderate Rain often occurs. Warm front Symbol
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
WIND Air particles moving from areas of high pressure to areas of low pressure.
H H L
Which kind of FRONT? Moving cold air slides under warm air. COLD FRONT
Which kind of FRONT? Add to notes in correct front Moving warm air pushes over cold air. WARM FRONT
Which kind of FRONT? Add to notes in correct front This symbol: WARM FRONT
Which kind of FRONT? Add to notes in correct front This symbol: COLD FRONT
Which kind of FRONT? Add to notes in correct front Heavy Rain often occurs. COLD FRONT
Which kind of FRONT? Add to notes in correct front Light or moderate rain precipitation can occur. WARM FRONT
Air particles moving from areas of high pressure to areas of low pressure describes…. WIND