draught, and the cyclonic movement quickly develops into a hurricane of tremendous energy. Hurricane winds at Galveston were estimated to have a velocity of 125 miles per hour; 100 miles per hour was registered before the anemometer was blown away.
According to Chief Forecaster E. H. Bowie, U. S. Weather Bureau, if a West Indian hurricane, moving westward in the longitude of eastern Cuba, is north of the island, it will recurve east of Florida, provided an area of high pressure covers the northwestern states. But if the hurricane is moving westward over Cuba or the western Caribbean Sea when an area of low pressure occupies the northwest, and the pressure is high in the eastern states, the storm will probably move to the Gulf of Mexico and reach the Gulf Coast after recurving.
Form and Dimension of Cyclonic Storms.—Extended measurements of the areas of low and of high pressure, made by Loomis and based on the isobars of the daily weather map, showed them to be elliptical in form, the longer axis usually pointing a little east of northeast. The average dimensions were found to be 1600 miles on the long axis by about one-half of that extent along the short axis. The average dimension of anticyclones is about the same. These values apply pretty closely to the dimensions of the cyclonic storms of western Europe.
The low of the West Indian hurricanes is very much smaller in area. Even after its existence has been discovered it may not be more than 100 miles in diameter; and by the time it passes a West Indian weather station it may not be more than 200 or 300 miles across. After it recurves and enters the United States, its area is much less than that of the ordinary cyclonic storm; the isobars are usually regular and more nearly of circular shape than those of ordinary storms.[1]
Storm Probabilities.—Before storm forecasts were sent to vessels by radio-telegraphy, the sailing master of the vessel was obliged to rely upon himself for weather predictions. He based his forecasts on his barometer, clouds, and the wind. A close study of these enabled him to make forecasts that were
- ↑ It is not unlikely that the eccentricity of the ellipse of the cyclonic storm depends on the velocity of the whirl—the higher the wind-velocity, the more nearly it approaches a circular form.
