Detecting Storms - The Doppler Weather Radar

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.

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.