Tornadoes: Granbury Residents Had Twenty Minute Warning



Residents of Granbury,  Texas, who suffered six deaths and at least one hundred people injured from the devastation of multiple tornadoes last Wednesday, had 26 minutes to prepare for impact.  That is double the usual warning time.

Scientists are of the opinion that the United States has fallen far behind other counties in its ability to predict weather patterns.  Before Hurricane Sandy struck last year, the National Weather Service believed that the hurricane would stay off the East Coast.  It was the Europeans who  predicted that Sandy would turn left into New Jersey. The National Oceanic and Atmospheric Administration released a report  finding that although National Weather Service did well at forecasting the path and impact of Hurricane Sandy, it did not issue warnings soon enough and failed in estimating storm surges.

The National Weather Service is getting an additional $25 million in its budget to update its computer mapping systems in in Reston, Virginia Silver Spring, Maryland, which will increase the agency’s computing power by 25 times.

Sometimes, weather forecasters are able to give several days’ warning that tornadoes are coming.  Last Wednesday afternoon, the National Weather Service was predicting hail and high winds to the west of the Dallas area, with possible isolated tornadoes, at 1:00 p.m.  by 5:00 p.m the first of many twisters were spotted.

Meteorologists say predictive ability has enormously increased in recent times.

Data about weather are gathered from thousands of sources, from across the globe are linked and their data pooled. Data can be gathered by wind gauges (anemometers), rain collectors and temperature sensors on the ground, strapped to buys in the sea, or riding along with commercial airliners.  Weather balloons are satellites are collecting data from scans of the upper atmosphere.  This results in more than 1 million weather-related observations every day.

Supercomputers residing at the National Centers for Environmental Prediction in Camp Springs, Md  absorb this data and use  complex mathematical models to do millions of calculations per second, predicting how weather conditions might change. Their prognostications are used by nearly every TV and radio stations to inform the public about the weather.

Forecasters who make predictions months in advance look for patterns in the current weather and compare them to similar patterns in prior years. This method doesn’t work very well.  Changes in the atmosphere are so complicated that even using weather events from a number of years back will not improve the accuracy of predictions.  The National Weather Service’s use of up-to-date mathematical and physical models will only provide two or three days of lead time. Even its specific forecasts ­of high and low temperatures and precipitation only reach forward  seven days.

The writers of most venerable prophetic voice, the Farmers’ Almanac, claim to use top-secret formulas provide 80 percent accuracy.  But predictions about the average temperature for the Atlantic corridor for March of 2013 were off by four degrees.  But relying on average past temperatures will allow you to make an equally good guess.

No methods of weather prediction have yet been able to reduce the deaths and injuries caused by natural disasters such as those that afflicted north Texas.






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