A tornado developed rapidly in the city of Independence, Iowa on the morning of 23 April 2001. It produced two minor injuries and F0 to F1 damage to homes. There was NO lightning associated with the storm while the tornado was on the ground (as reported by spotters and the NLDN). The NWS Storm Prediction Center did not have the area in a risk of severe weather, and there was no anticipation of tornadic storms that morning by the NWS office in Davenport.

Environmental clues were mixed regarding tornadic potential. Instability was modest (< 1000J/kg CAPE) though shear was quite high (SREH ~650 m2s2) and absolute wind speeds were rather strong. Radar data provided little, if any, evidence that a tornado even occurred. The highest reflectivity values observed during the tornado were 35-40 dBZ, and there was no evidence of a circulation in the velocity data. Several issues contributed to the lack of quality radar data including beam height and width at long range, temporal sampling issues, range folding, and algorithm limitations.

The presentation will review the radar imagery associated with this unique tornadic storm, discuss the radar’s limitations in this event, and discuss the importance of a well trained spotter network, especially in areas far from the WSR-88D.