Monday, August 4, 2008

Much To Talk About

It will be a busy week for weather headlines with Tropical Storm Edouard topping them most likely.

This system developed over the weekend out of a cluster of unsettled weather over the northeast Gulf of Mexico.

The storm is moving west and should make landfall near Houston, TX by Wednesday.

It could pull a "Dolly" and strengthen into a hurricane before landfall.

Either way, it will be a wet and stormy time for residents along the upper Texas coast and in portions of coastal Louisiana.

Meanwhile, the bubble of extreme heat will shift east this week. Here in Denver we will finall break our 90° streak on Tuesday if the forecast holds. That would make the new record streak of 90 degrees or higher stand at 23 days.

Recall we broke the previous streak of 18 days last week. That record was originally set in 1874 and tied again in 1901.

The streak of 100s will continue for Dallas, TX and more record highs are possible today over the plains states.

Here are some record highs from Sunday around the country...

  • 107° Dallas/Ft. Worth Airport, TX (previous 105° in 1998)
  • 106° Oklahoma City, OK (tied - previously in 1930)
  • 105° McAlester, OK (previous 103° set in 1956)
  • 104° N. Little Rock, AR (previous 103° set in 1987)
  • 103° Pueblo, CO (tied - previously in 1902)

    Today's Lesson

    Billions of air molecules push on the human body. This force is exerted equally in all directions.

    At the same time, billions of molecules on the inside of the body push outward just as hard -- which balances the force.

    We don't directly feel these "pushing" forces of the air, but we can detect changes in air pressure quickly. (i.e. ears popping when we rapidly change elevation)

    Air molecules both take up space and have weight. In fact air is heavy -- with the weight of all the air around the Earth coming in at a staggering 5600 trillion tons.

    This weight acts as a force upon the Earth.

    The amount of force exerted over an area of surface is called atmospheric pressure, or simply, air pressure.

    As you climb in elevation from sea level, the air pressure decreases -- rapidly at first through the first 10 miles, then more slowly.

    So if you have ever been here in Colorado, and visited any of our 54 mountain peaks that top 14,000 feet -- you have been above nearly half of all the molecules in the atmosphere.

    The summit of Mt. Everest is above nearly 70% of all the molecules in the atmosphere. (approx. 29,000 feet)

    So far, through our daily blog lessons, you have learned that both air pressure and air density decreases with height above the Earth's surface.

    Temperature is a different story, however. It has a much more complicated vertical profile.

    We are often led to believe that it cools with height overall, bit is that really so?

    Tune in tomorrow and we'll find out!
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