IT'S GON' RAIN

An Introduction to Regional Geography and Meteorology

Introduction

Everyone watches the weatherman on the local news channel. A lot of the time, we complain about they are incorrect - "they were 10 degrees off", "it did not rain but they said it would", etc., etc. This flier exists to educate individuals who are curious as to the BASIC workings of atmospheric meteorology and regional geography. There is a complicated world of variables that influence the weather. Understanding these influential factors will help readers contextualize the natural world around them.

Global Atmospheric Weather Trends

Global Winds - large systems of moving air that follow similar patterns of movement over time and are influenced by cosmic factors such as the Coriolis Effect and solar radiation.


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?

Warm Front - A large mass of air that is high in temperature and humidity.


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.

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The above picture depicts an Incoming Cold Front edge and how it affects the air mass in front of it. See What Happens When Air Masses Interact for a description.

North American/American Regional Geographic Characteristics

The North American continent is one of the most diverse and volatile on Earth. Across the continent volcanoes, floods, droughts, hurricanes, tornadoes, and earthquakes are all common experiences. Additionally the United States is home to arid deserts (bottom left of below picture), various mountain ranges (on the left of the picture below), vast deciduous forests (all of the green in the East as well as the North West), and the largest continuous fertile agricultural growing area in the world - known as the "Breadbasket" (in between the mountains and the forests). The vast diversity in geography and area allows for a wide array of meteorological experiences and variance in general weather trends.


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.

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Why Does This Matter to You?

A working knowledge of the complexities that go into the weather we experience every day helps individuals be more aware of the world around them. Additionally, noticing trends in these experiences may help inform people how to predict what to wear over the period of a few days, what kind of weather may be coming next, and possibly how severe it will be.


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.

Informational Sources

PBS. (n.d.). Guns, Germs, Steel. Retrieved from http://www.pbs.org/gunsgermssteel/world/pup/world_intro.html


NOAA Education. (n.d.) Weather and Atmosphere. Retrieved from

http://www.education.noaa.gov/Weather_and_Atmosphere/Weather_Systems_and_Patterns.html


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