English: Radar imagery of the tornado outbreak. Imagery on the left is of storm reflectivity. Notice how the classic hook-like apendage takes shape as the storm moves across the northeast part of the city. The hook-like feature in a strong thunderstorm is often a good sign that the storm is producing a tornado. Imagery on the right is of storm relative velocity. Shades of red indicate air which is moving away from the radar while shades of green indicate air which is moving toward the radar. The brighter shades highlight the faster moving air. The bright reds and greens directly next to each other indicate strong rotation.