Doppler Weather Radar

Doppler weather radar has come a long way since its beginning. In 1964, the first Doppler radar was commissioned by the National Oceanic and Atmospheric Administration (NOAA). The NOAA used the first 3-cm Doppler to receive radio signals from storms. The first few instances of "tornado tracking" were experimental, and soon the NOAA scientists realized that this system was not the best radar, since it was not big enough to receive all the necessary signals. In 1973, the NOAA's recently upgraded 10-cm Doppler was observed by the National Severe Storms Laboratory (NSSL). For the first time in history, a tornado's life cycle was captured both in data and on film. This data revealed the tornado's circular motion, and the clouds inside the storm rotating around a centripetal point of rotation. This weather detector radar system would help increase the time for getting out severe weather reports to the residents of the area.

In 1964, the National Oceanic and Atmospheric Administration (NOAA) commissioned the first Doppler weather radar. The 3-cm Doppler was used to receive radio signals from storms, and was soon used in experimental "tornado tracking." Through these experiments, scientists realized the radar was not yet powerful enough to track all of the necessary data. In 1973, the NOAA upgraded to a 10-cm Doppler, observed by the National Severe Storms Laboratory (NSSL). This first tornado's life cycle was captured both on film and in data, and revealed the circular pattern of a tornado's winds. This was the beginning of being able to send out severe weather reports faster.

The first Doppler weather radar was commissioned in 1964 by the National Oceanic and Atmospheric Administration, or NOAA. When scientists experimented with tornados, they quickly realized the 3-cm Doppler was not big or powerful enough to receive and track all of the needed information. They realized this one radar would need improvements. The National Severe Storms Laboratory (NSSL) observed NOAA's upgraded 10-cm Doppler in 1973, which was able to track a tornado's life cycle. This data told scientists of the circular motion of a tornado's winds, as well as the centripetal point of rotation, which the inner clouds rotate around.

In 1964, the first Doppler weather radar commissioned by the National Oceanic and Atmospheric Administration (NOAA) was a 3-cm Doppler, used to receive signals from storms. When this weather detector radar system was used for tornado tracking, scientists quickly realized this Doppler was not the best radar system to receive all of the necessary signals. In 1973, the NOAA upgraded to a 10-cm Doppler, which was observed by the National Severe Storms Laboratory (NSSL). A tornado's life cycle was captured through film and data for the first time in history, giving scientists a better picture of the circular wind patterns and central rotation point known to tornados.

Scientists sought to increase their knowledge of how storms like these formed. One particular storm in May of 1973 cut right through the heart of Union City, Oklahoma. Union City lies in the center of the infamous "Tornado Alley" region of the United States. With the data received by the scientists, they were able to start planning upgrades and improvements of the Doppler weather radar so it could be a more reliable asset to the government and the residents. The Doppler system maps weather radar by measuring the motion inside these very hostile storms. Over time, scientists discovered that tornadoes produce a unique signature; different from regular storms. And as time went on, they were able to recognize this pattern, which they later called the "tornadic vortex" signature.

Improvements to the Doppler weather radar increased the warning time for tornados. The NEXRAD (Next Generation Radar) increased the accuracy of radar readings, giving scientists a clearer picture with which to work. With NEXRAD, scientists all over the country could communicate data to predict the path of a tornado. Since the NEXRAD upgrade, the lead time for early warnings for severe weather reports has increased dramatically. Previously, residents had about a 5 minutes warning, yet a tornado that struck Enterprise, Alabama in 2007 had a remarkable 18 minute lead time. In that particular storm, the National Weather Service measured tornadic rotation in the clouds, noting the storm was producing the signature "hook echo." A warning was issued for the residents of Enterprise, Alabama to take cover from this impending tornado. Eighteen minutes later, the tornado touched down.

Doppler weather radar improvements, including NEXRAD (Next Generation Radar), increased the warning time and the path prediction accuracy in storms with tornadic activity. Using NEXRAD, scientists nationwide are able to share data, giving a clearer picture of what to expect. In 2007, the National Weather Service picked up on tornadic cloud rotation and signature "hook-echo" patterns. Residents of Enterprise, Alabama were warned to take cover, and a full eighteen minutes later the tornado touched ground. Thanks to NEXRAD, the previous, typical five minute warning time to get to a safe place finally saw a dramatic increase.

One of the biggest improvements to Doppler weather radar technology is NEXRAD (Next Generation Radar). NEXRAD's Doppler network allows scientists nationwide to share and compare storm paths and wind patterns, increasing warning times for severe weather reports and accuracy in path prediction for storms showing tornadic activity. Whereas residents could previously expect a five minute warning before a tornado touched down in their area, this timeframe dramatically increased in 2007. Based on cloud rotation and "hook-echo" patterns noted, the National Weather Service issued a warning to residents of Enterprise, Alabama to take cover. Eighteen minutes later, a tornado ripped through their town.

Eighteen minutes is ample time to gather family and emergency supplies and take shelter. It was also enough time for some commuters to seek shelter in a sturdy building and get off the streets. It is the goal of all meteorologists to increase the lead time to 20 minutes, saving many more lives in the process. Doppler weather radar has come a long way. In the beginning, scientists hoped to save lives by getting the severe weather reports announced faster. Now, almost forty-five years since its birth, this one radar system is doing exactly that.

While eighteen minutes will never seem like enough warning when your town and your home is about to be destroyed, it does give enough time to gather family, pets, and emergency supplies before taking shelter. It is the hope of meteorologists everywhere to increase the warning time on severe weather reports to at least twenty minutes, thus saving more lives. Almost forty-five years after its birth, Doppler weather radar has come much closer to realizing that goal.

No amount of time will ever seem like enough to prepare yourself for the shock and fear a tornado can bring. Eighteen minutes won't save your home, your business, or your car. But it provides enough time to help your loved ones get to a safe shelter, as well as to gather some emergency supplies. In the beginning, Doppler weather radar technology was created to increase warning times for these severe weather reports and save lives. Forty-five years later, amazing breakthroughs are achieving that goal.

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