Funnel cloud forms in Auckland sky

Brett Agnew took this picture of a funnel cloud over the skies of Pakuranga. Photo / Brett Agnew

Several nzherald.co.nz readers have been sending in photos of what appears to be a tornado forming over South Auckland.

MetService forecaster Paul Mallinson says it is, in fact, a funnel cloud, which forms on a seabreeze convergence - when an easterly meets a westerly.

Mr Mallinson says the cloud is consistent with conditions and not particularly unusual.

WeatherWatch.co.nz's head weather analyst Philip Duncan says this evening's funnel cloud was caused by a mixture of cooler air and warmer air moving in different directions at different altitudes.

"The different temperatures and airflows caused the clouds to rotate, producing a funnel cloud."

As it is now dissipating, the funnel cloud is unlikely to become a tornado.

"By definition, it's a funnel cloud in the air and if it reaches the ground, you start thinking about calling it a tornado," says Mr Mallinson.

"If it had touched down on the surface and it formed over water, it might have formed a water spout."

- NZ Herald staff