Both Dick Smith and John Wallington praised the Australian Bureau of Meteorology for their computer modelling of conditions over the Tasman. Very localised events are too chaotic for the machines to predict, he says. This is what happened on the morning of the second day when a weak front pushed into the high, creating northerly winds ahead of the change. These northerlies weren't expected, but the computer model did note that if the balloonists rose a few thousand feet, they would find a stream of easterly air. They followed the bureau's advice, found the easterly stream and the rest is history.
American meteorologist explains 'blocking highs'.