More accurate weather forecasts predicted

Weather forecasts that miss storms or sometimes just plain get it wrong could soon be an annoyance of the past.

National Institute of Water and Atmospheric Research scientists are working on new modelling systems they hope will bring unparalleled accuracy to predicting severe storms and flooding.

The results of trials should be known in a few months, setting up New Zealand to become the second country in the world after Britain to use the systems.

Niwa principal scientist Michael Uddstrom said weather models predicted the intense rainfall that flooded parts of Porirua on Sunday, but though they got the timing and intensity right, they got the place wrong by putting the location of heavy rain to the north and over the sea.

The researchers were developing a more sophisticated model to improve the accuracy of forecasting.

At the moment, they divided the country in to 12-kilometre grids, but Niwa was testing using grids 64 times smaller for future modelling.

"One of the really interesting elements about New Zealand is its topography," Dr Uddstrom said.

"What we need to do in order to get locations of events better, we believe, is to be able to resolve the processes that our landscapes induce on the weather."

As landforms such as mountain ranges and valleys all impacted on the weather, mapping them with more accuracy would improve forecasting abilities, Dr Uddstrom said.

Niwa would use its "super computer" for one hour four times a day to generate 24-hour forecasts.

Improved modelling would help provide new capabilities for predicting extreme weather events and consequences such as flooding.

Niwa scientists were working with regional councils to help them use the information and develop tools to generate severe weather warnings.

The Dominion Post