Meteorology of the Hugo tornado

This is the first anniversary of the Hugo tornado. The staff at the Chanhassen NWS office put together a nice summary of the details of this storm and the meteorological conditions.

I have seen two presentations from research work conducted on this storm. Indeed, the Doppler radar indicated strong mid level rotation in the thunderstorm as it moved over northern Wright County. Spotters had observed a rotating wall cloud and a tornado warning was issued based on the combination of the two observations.

Although no additional reports of a wall cloud or a funnel cloud were received by the NWS, they reissued the tornado warning for the Hugo area. The reissuance of a tornado warning resulted in the second activation of the outdoor warning siren. Some speculate that this second sounding of the siren may have been mistakenly inferred as an ALL CLEAR.

To my knowledge, as the former chief of the NWS office, there is no policy where the sirens are sounded for an ALL CLEAR.

Spotters believe that the circulation of the twister was hidden by heavy rain. Thus there were no photographs of the tornado as it struck Hugo. There was a considerable lead time in the Tornado Warning from the NWS based exclusively on the strong rotation shown on the Doppler radar.

Chanhassen NWS review of the Hugo tornado of 2008. Click on radar image for greater definition.

CE