Whether you actively seek the thrill of a good lightning storm or you need to make sure your nervous dog is inside in your protective arms when a thunderstorm hits, MetService has got your back.

The word ‘storm’ is frequently misused in the media and colloquially, almost as much as the misuse of the term ‘weather bomb’*.  In the strictest meteorological sense, a ‘storm’ is only a storm if accompanied by storm-force winds, which are defined by the Beaufort scale as having an average speed of over 47 knots (88 km/h). However, there are several other types of storm which don’t require storm-force winds.

Sitting out in the middle of the ocean, New Zealand is vulnerable to weather extremes from all directions, from the remains of tropical systems barreling in from the north, to cold winter southerlies bringing a blanket of snow.

Sitting out in the middle of the ocean, New Zealand is vulnerable to extremes of weather from all directions; from the remains of tropical systems barrelling in from the north, to cold winter southerlies bringing a blanket of snow.

As New Zealand’s designated national meteorological service to the World Meteorological Organisation (WMO), it is MetService's responsibility to provide clear, concise and timely warnings of severe weather that is likely to affect New Zealand.

What defines severe?

Few weather events are as dramatic, dangerous or challenging to predict as tornadoes.

About the tornado of Tuesday 3 May 2011

On the afternoon of Tuesday 3 May 2011, a line of showers moved southwards across Northland. Ahead of this line the winds were moderate northeasterlies; behind it, they were moderate northwesterlies. Along the line, the winds converged - that is, pushed against each other. Below is a portion of a working chart for 3:00pm Tuesday 3 May 2011, drawn by one of the Severe Weather Forecasters.

From Wednesday 01 July 2009, MetService has been providing a Severe Thunderstorm Warning Service. This blog entry explains why we are able to do this, why warnings of thunderstorms are different from warnings of broad-scale weather events, which parts of New Zealand they will apply for, how you can receive them and what actions you can take to protect yourself.