NO HURRICANE TONIGHT
By Philip Ball
1 Isn’t it strange how we like to regard weather forecasting as a uniquely incompetent science—as
though this subject of vital economic and social importance can attract only the most inept researchers,
armed with bungling, bogus theories?
2 That joke, however, is becoming less funny. With Britain’s, and probably the world’s, weather
becoming more variable and prone to extremes, an inaccurate forecast risks more than a wet garden
party, potentially leaving us unprepared for life-threatening floods or ruined harvests.
3 Perhaps this new need to take forecasting seriously will eventually win it the respect it deserves.
Part of the reason we love to highlight the disastrously misplaced reassurance from Michael Fish, the
BBC’s TV weatherman, is that there has been no comparable failure since. “Earlier today,” said Fish,
“apparently, a woman phoned the BBC and said she heard there was a hurricane on the way; well, if
you’re watching, don’t worry – there isn’t.” Hours later, the great storm of 1987 struck. As meteorologists
and applied mathematicians Ian Roulstone and John Norbury point out in their account of the maths of
weather prediction, Invisible in the Storm, the five-day forecast is, at least in western Europe, now more
reliable than the three-day forecast was when the 1987 storm raged. There has been a steady
improvement in accuracy over this period and, popular wisdom to the contrary, prediction has long been
far superior to simply assuming that tomorrow´s weather will be the same as today’s.
4 Weather forecasting is hard not in the way that fundamental physics is hard. It’s not that the
ideas are so confusing, but that the basic equations are extremely tough to solve, and that hiding within
them is a barrier to prediction that must defeat even the most profound mind. Weather is intrinsically
unknowable more than two weeks ahead, because it is an example of a chaotic system, in which
imperceptible differences in two initial states can blossom into grossly different eventual outcomes.
Indeed, it was the work of the American meteorologist Edward Lorenz in the 1960s, using a set of highly
simplified equations to determine patterns of atmospheric convection, that first alerted the scientific
community to the notion of chaos: the inevitable divergence of all but identical initial states as they
evolve over time.
5 It’s not obvious that weather should be susceptible to mathematical analysis in the first place.
Wind and rain and blazing heat seem subject to caprice, and it’s no wonder they were long considered a
matter of divine providence.
Adapted from Prospect, February, 2013
According to the information in the article, Michael Fish
