Air Masses, Fronts

A huge body of air that has similar temperature, humidity and air pressure at any given height.

Prevailing Westerlies: Push air masses from West to East. Jet Streams: Embedded within Prevailing Westerlies, they are bands of high-speed winds about 10 kilometers above earth's surface. The air masses are carried by jet streams.

Maritime Polar, Maritime Tropical, Continental Polar, and Continental Tropical

Forms over northern Pacific and Atlantic oceans. Brings cool, humid air to west coast. Masses from Atlantic Ocean often pushed to sea by westerly winds.

Forms over southern Pacofic Ocean and Atlantic Ocean-Gulf of Mexico. Pacific masses generally affect West Coast. Atlantic-Gulf of Mexico masses start southeastern US, move north and northeast.

Cold, clear, dry air forms over central and northern Canada and Alaska. Bitter, cold weather moves through much of central and eastern US

Hot, dry air masses mostly in summer areas to southwest and northern Mexico.

A collision of air masses, a boundary where they meet.

Cold front, Warm front, Stationary front, and Occluded front.

Cold air is dense and sinks. Occurs when fast-moving cold air mass runs into slow moving warm air mass and slips under warm mass. Warm air rises untill it reaches dew point.f warm air had a lot of vapor, heavy rain or snow follows. If not, cloudy skies most likely. Cold fromts move QUICKLY, can cause abrupt changes, thunderstorms. After a cold front, colder, drier air, clear skies, lower temperatures.

Fast moving warm air mass runs into slow moving cold air mass. Warm air moves over denser cold air. If warm air is humid, result might be light rain or snow. If warm air is dry, scattered clouds might form. Warm fronts move SLOWLY weather may stay the same for days. Area likely to be warm and humid afterwards.

Cold and warm air masses coming together. Neither can move. Precipitation occurs as water vapor in warm air condenses.

Warm air is caught between two cold fronts. Cooler air mixes, cuts off warm air mass, leading to colder temperature on ground. Warm air cools, water vapor cools, leads to clouds andpossibly precipitation.

Air masses collide, from fronts, and boundary between fronts sometimes distorted due to mountians, strong winds. Bends develop along front, air begins to swirl, and a low-pressure center can develop.

Swirling center of low air pressure. Warm air from center rises and air pressure decreases. Cooler air blows towrd this area from nearby where air pressure is higher. Winds spiral inward and counter clockwise. What results from cycloned are winds, recipitation, and clouds.