Perfect Weather Predictions
by Lauren Whisenhunt
CBS 42 News
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People rely on meteorologists every day to help plan their lives. Whether it be brides on their wedding day or students getting ready for school. People want to know if they’ll need a jacket that day or an umbrella.
But one wrong forecast and local meteorologists are the first to get blamed. Predicting the weather isn't easy, but despite a few missed temperatures, weather forecasting has actually made huge improvements in the last 20 years.
Forecasting severe weather has dramatically increased in accuracy over the years. Also, predicting where a hurricane is headed and where it will end up has improved. In 1985, forecasters predicted a hurricane's path 366 miles wide. Now, a hurricane's path can be predicted down to within a 111 mile-wide path. That's a 67 percent increase in accuracy!
Meteorologists at the National Oceanic and Atmospheric Administration are expecting even more improvement, which will continue during the next decade or so as they fly aircraft's inside the inner core of the storm to learn more information.
Technology advances in radar and satellites has also helped daily forecasts improve. A four-day forecast today is better than a two-day forecast was back in the mid 1980's. It gets even better than that. Now, our six-day forecasts are as accurate as our three-day forecasts used to be.
NOAA meteorologists say that their three-day forecasts are accurate 75 percent of the time within five degrees. Now that’s impressive!
Daily forecasting continues to improve, so the chance of a perfect forecast increases almost every day.
WHAT'S THE FORECAST: Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. Humankind has attempted to predict the weather since ancient times. In 650 B.C., the Babylonians predicted the weather from cloud patterns. Chinese weather prediction lore extends at least as far back as 300 B.C. Ancient weather forecasting methods usually relied on observed patterns of events. For example, it might be observed that if the sunset was particularly red, the following day often brought fair weather. This experience accumulated over the generations to produce weather lore. Today, weather forecasts are made by collecting data about the current state of the atmosphere and using computer models of the atmospheric processes to project how the atmosphere will evolve.
HOW STORMS DEVELOP: Storm clouds form as moisture evaporates from the Earth into the atmosphere, where the droplets congregate and jostle against each other. The air cools off rapidly with altitude and the water vapor condenses into liquid drops, forming clouds. The process continues: more and more water vapor turns into liquid and the moist air warms up even more and rises higher and higher. The severity of a storm will depend largely on the buoyancy of the rising air within the storm and the structure of the wind within the atmosphere.
WHAT IS DOPPLER RADAR: Doppler radar uses a well-known effect of light called the Doppler shift. Just as a train whistle sounds higher as it approaches a platform and becomes lower in pitch as it moves away, light emitted by a moving object is perceived to increase in frequency (a blue shift) if it is moving toward the observer. If the object is moving away, it will shift toward the red end of the spectrum. Doppler radar sends out radio waves that bounce off objects in the air, such as raindrops or snow crystals, and then measures how much the frequency changes in returning radio waves to better determine wind direction and speed.
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