Ah, Nebraska—such a wonderful place to sit outside with a
cold beverage at dusk while watching the sunset (for only about nine days a
year). As is true with other states in the Great Plains, Nebraska’s weather is
quite unpredictable and interesting as the state experiences everything from
sub-zero to 100+ degree temperatures, floods, droughts and snow storms that
leave evidence of their existence for weeks.
The unpredictability of Nebraska weather is caused by many
different elements, including wind patterns and physical geography.
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| Wind Patterns during a June, 2009 Storm http://extremeinstability.com/wx101.htm |
The wind patterns pictured above show black lines
representative of surface winds coming from the West and the South and the
white lines indicate winds at 18,000 feet. There are two elements that cause
Nebraska (or anyplace) to have wind: pressure gradients and the Coriolis
Effect. Pressure gradients affect air as it moves from high to low-pressure
areas—measured in isobars. As the Great Plains cover a range with steep
pressure gradients, the wind is faster (the gradients become steep when the are
spread affected strongly in a short amount of space. The Coriolis Effect is
essentially taking the Earth’s spin into account when establishing the
direction of the wind. As air moves towards higher-pressure areas, Northern air
is drawn South towards the Equator.
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| Example of Coriolis Effect http://www.waterencyclopedia.com/Ce-Cr/Climate-and-the-Ocean.html#b |
The collision of cold, Northern air and moist, warm air from
the Gulf of Mexico is not the only reason for Nebraska’s unpredictable
weather—the general flatness of Nebraska also plays a roll. Whereas here in
Denver, the Rocky Mountains prevent Arctic or Gulf air masses from going West,
they also provide a predictable cloud location as warm air moves up the
mountains and settles. As Eastern Nebraska sits at 1,000 feet above sea level
and the West can rise to over 4,000 feet above sea level, the gradual slope
causes no blatant predictable storm locations.
http://en.wikipedia.org/wiki/Contour_line#Barometric_pressure
