Windswept_ The Story of Wind and Weather - Marq de Villiers [85]
These tropical depressions are already convection engines, their fuel provided by the warm sea water, which evaporates ever faster in the higher winds, causing ever lower pressures. After a few days, the tropical depression may escalate into a tropical storm. If the sustained winds reach 38 miles an hour, the meteorologists reach for their naming dictionaries and give the new storm a moniker.
The practice of giving storms names rather than geographic locator numbers began in the final years of the nineteenth century in Australia, where forecaster Clement Wragge cheekily gave destructive typhoons the names of women he knew (or wanted to know), or politicians he thought were idiots. Bob Sheets, former director of the National Hurricane Center, credits a 1941 novel called Storm, by George R. Stewart, for bringing the practice to the Atlantic. Sheets notes: "It was easier, the hero said, to say 'Antonia,' rather than 'the low pressure center which was yesterday in latitude 155 E, longitude 42 N.' "19 In World War II, military forecasters helped pilots to keep various systems separate with names rather than coordinates; the assigned names were random but always female, generally the names of wives, girlfriends, or, like Clement Wragge before them, women the forecasters hoped would be girlfriends. It wasn't until the 1970s that the practice was systematized. At that time forecaster Gil Clark drew up a list of women's names from baby-naming books and his own family. Men's names were added by the fiat of the World Meteorological Organization, under pressure from an indignant woman's movement, in 1978. Bob, a curiously boyish name for a major force of destruction, is the first male hurricane on record.20 Gilbert, Clark's own given name, by coincidence still holds the record for the most intense Atlantic storm on record, with a low pressure recorded at 888 millibars. The world-record low pressure is 870 millibars measured in Guam in 1979.
At 74 miles an hour, when a tropical storm becomes a baby hurricane, pressure can drop very rapidly from the periphery to the center—pressure has been tracked to drop 38 millibars in thirty minutes in particularly severe storms. The energy is enormous—even a moderate hurricane releases enough energy in a single day to equal four hundred 20-megaton nuclear bombs; if converted to electricity, it would be enough to power all of New England for a decade, with enough left over to run toasters all over the Canadian Maritimes.
Meanwhile, the whole system is moving—for both Atlantic hurricanes and Pacific typhoons, generally westward at first, then curving northward and eventually northeast. This is why, in the northern hemisphere, winds are strongest to the storm's right, where the directional speed of the storm's travel is added to its rotational speed. To its left, the forward speed mitigates the observed wind speed. The faster the storm is going the more exaggerated this effect. If a hurricane is going to hit, you should hope you're to its left.
When a small hurricane's convection pattern strengthens, the centripetal wind flow gains speed, the input of warm moist air continues to escalate, even more large-scale condensation