While Hurricane Irma gains strength and former Hurricane Harvey continues to cause flooding Arkansas, Kentucky, Mississippi and Tennessee, here are some facts about the storms.
Irma is a solid 5
True: Hurricane Irma is a Category 5 on the Saffir–Simpson hurricane wind scale, and it has sustained winds of 175 mph. Monroe County in Florida, which includes the Florida keys, expects to issue a mandatory evacuation for all visitors on Wednesday.
False: It is not a Category 6. There is no “6” on the Saffir-Simpson scale, Category 5 is as high as it goes.
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Irma is heading straight for ...
True: On Tuesday morning, Irma is east of the Leeward Islands, including Barbados and St. Lucia, and headed west at 12 knots, or about 14 miles an hour.
False: Straight for the Keys, of the Florida Peninsula, or ___. Forecasts are confident that the hurricane is “expected to affect” the Leeward Islands as a tropical storm later Tuesday before the full storm arrives. Beyond that, the National Hurricane Center says it “is still too early to determine what direct impacts Irma might have on the continental United States.”
Cone versus Spaghetti models
Cone: The National Hurricane Center uses a cone model to track the probable path a storm may take. The overlapping circles on a map reflect “that two-thirds of historical official forecast errors over a 5-year sample fall within the circle,” the NHC says.
The cone is designed to show the area that the eye could follow, and does not show the full impact of the possible storm. It is also referred to as the “cone of uncertainty."
Spaghetti: Other agencies use the so-called spaghetti model, where lines are drawn between pointed plots of where and win a storm might hit. Spaghetti models do not show any representative of size or intensity, and vary according to which forecast is used. There are more than 20 models used for intensity, rainfall, wind and other storm factors.