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This radar image was taken near the time the cold air funnel occurred. The storm (or shower) which produced the funnel cloud was significantly weaker than a typical supercell thunderstorm. In fact, cold air funnels typically occur in weak showers such as this one. As you can see, this makes it very difficult for a meteorologist to know if a storm is producing a cold air funnel by looking at radar. The "what's going on in this picture" link provides an explanation how such a weak shower could have produced a funnel cloud in this case.