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Example of WDSS display at 6:51 CDT during the May 3, 1999 tornado event. The table at the top shows the relative ranking of all storms at that time. The left graphic is the reflectivity field from the NEXRAD, the right is the velocity field. The squares on the left image show the location of detected storms, the triangle on the right shows the location of the detected tornado, and the yellow circle shows the location of the larger circulation. The white dotted lines are the past tracks and the cyan cross-haired lines are the forecasted positions, with each cross- hair the location at five-minute intervals. |
WDSS proves invaluable
The WDSS was developed by NSSL to meet the needs of forecasters in NWS offices to help them make timely, effective and efficient warning decisions regarding severe weather, tornadoes and flash floods.
On May 3, 1999 a series of tornadoes occurred in Oklahoma that claimed 42 lives and caused over $1 billion in damage. Although there were many lives lost, the number was significantly reduced by the long lead-time warnings (20-60 minutes) that were provided by the NWS to the general public.
The NWS forecasters relied on the WDSS to help them make these very timely and accurate tornado warning decisions. David Andra, the Scientific Operations Officer at the Norman NWS office, utilized the WDSS to help make warning decisions on this day. Andra said that the WDSS greatly increased forecaster's confidence in their warnings by allowing them to be more precise. WDSS also allowed them to determine the exact character and movement of the tornadoes with better fidelity. In addition, the WDSS's ability to automatically examine, every five minutes, the numerous storms on this day and tell which storms were most likely to be tornadic and/or severe helped them manage their time and focus on the most serious threats.
The combination of the WDSS with NEXRAD and AWIPS provided the necessary
technology to the forecast office to allow it to issue excellent tornado
warnings to the public on this day, ultimately saving many lives.
