A pocket of thunderstorm warnings, marked "low risk", hovered over Gisborne's New Year's Eve celebrations last night, but for weather scientists it's almost impossible to be any more precise.
The 30,000 revellers at the annual Rhythm and Vines concerts there may have wanted more, but pinpointing exactly where thunderstorms will erupt, in a timeframe that is helpful to people likely to be affected, remains an unattained "holy grail" for scientists, according to Dr Mike Revell, principal scientist at the National Institute of Water and Atmospheric Research (Niwa).
"At the moment, our computer models are very effective at forecasting the conditions under which thunderstorms are likely to develop over an area of several hundred square kilometres," he said.
"But we remain some way off being able to forecast exactly when and where, within the several-hundred-square-kilometre area, those individual cells will develop."
Dr Revell said it was worth looking out for the distinct, menacing, cauliflower-like clouds of a developing thunderstorm. "The convection process begins when the sun rises and starts to heat the land surface. Then, depending on atmospheric conditions, the thunderstorms are ready to break by about mid-afternoon."
