IT'S GON' RAIN
An Introduction to Regional Geography and Meteorology
Global Atmospheric Weather Trends
Air Masses - large bodies of air that are controlled and manipulated in space by global winds.
Jet Streams - narrow bands of strong wind that exist high in the atmosphere and transfer heat and moisture around the globe. Created by Convection Currents being bent, due to the spin/tilt of the Earth.
Convection Current - Uneven heating by sun creates different air circulation patterns. Lots of energy near the equator produces hot humid air that rises quickly. A low pressure area forms at the surface and a region of clouds forms at high altitude. The air eventually rises high enough that it cools off and falls back down to different areas of the Earth.
What Happens When Air Masses Meet?
Cool Front - A large mass of air that is low in temperature and humidity.
Occluded Front - A front that forms when a cold air mass "catches up" to a warm air mass and begins to isolate a small pocket of warm, moist air.
Basic Summary of How Air Masses Interact:
When Warm Fronts are moving in, you can see evidence of it high in the atmosphere first. Warm air is less dense and thus rises, making the first wave of warm air come in high in the atmosphere. As this happens the warm air cools and condenses, forming water droplets or ice crystals - clouds. Warm fronts bring with them shorter spells of heavy rain followed by long periods of light rain. This process is slow developing compared to a Cold Front because the leading edge of Warm Fronts are not steep, and begin high in the air.
When a Cold Front approaches a Warm Front, the incoming cool air is denser and closer to the ground. As Cold Fronts approach a warmer air mass, they do so quickly because the leading edge of the front is sharper. The rapid spike in air pressure creates deep cloud layers which bring bands of rain and sometimes thunder as the edge passes over.
North American/American Regional Geographic Characteristics
As seen in the above sections, altitude of air masses effects how precipitation occurs on a basic level. Other factors such as humidity, pressure, change in temperature, and ground surface formation can also change the way air masses interact with each other. Part of the reason the U.S., and North America in general, sees such an array of meteorological activity have to do with the geographical features the land contains.
Why Does This Matter to You?
Furthermore, understanding the kind of geography our country and continent have informs people of the factors that their countrymen live with everyday. This knowledge is helpful to inform a conception of the world, but also to increase understanding of different ways of life within our own country. We often do not realize how much the weather effects our way of life and paying more attention to this may help people live happier lives.
Also, it may help us sympathize with the weather man... and maybe cut him a break.
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NOAA Education. (n.d.) Weather and Atmosphere. Retrieved from
National Weather Service. (2010). Jetstream – Online School for Weather. Retrieved from http://www.srh.noaa.gov/srh/jetstream/synoptic/synoptic_intro.htm
Met Office. (May 8, 2012). What are Weather Fronts? Retrieved from https://www.youtube.com/watch?v=G7Ewqm0YHUI