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Two Tropical Depressions Form in One Day

Tropical Depression 18
This visible image of Tropical Depression 18 was taken from NOAA's GOES-13 satellite on Oct. 22 at 1145 UTC (7:45 a.m. EDT) just before it was classified as a depression. (Image credit: NASA GOES Project )

The 2012 Atlantic hurricane season has livened up again with the formation of the 18th and 18th tropical depressions of the season.

Tropical Depression 18 had formed in the Caribbean Sea as of 11 a.m. EDT this morning (Oct. 22) and Tropical Depression 19 followed out in the Atlantic at 4 p.m. EDT, according to updates from the National Hurricane Center (NHC). Both storms are expected to strengthen into tropical storms, and will be named Sandy and Tony, respectively, the next names on the 2012 hurricane name list.

A tropical depression is a tropical cyclone (the generic names for hurricanes, tropical storms and typhoons) with maximum sustained wind speeds of 38 mph (62 kph) or less. A depression becomes a tropical storm when it exceeds that threshold and then a hurricane when its winds surpass 74 mph (TK kph).

If these two depressions do become tropical storms, they will be the 18th and 19th named storms of the season, which was only expected to see 12 to 17 named storms (those that achieve tropical storm status or higher). An average hurricane season sees 11 named storms, six hurricanes and two major hurricanes.

These storms have come at the "second peak" of the hurricane season, a smaller spike that occurs in mid-October, after the main peak of the season, which occurs around August-September.

A tropical storm watch is already in effect for Jamaica, where what will become Sandy is expected to bring rains of 5 to 10 inches to Jamaica, Haiti, the Dominican Republic and eastern Cuba, the NHC said. Some isolated spots could see as much as 16 inches of rain.

The Atlantic hurricane season officially ends on Nov. 30, but storms have been known to form after that date.

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Live Science Staff
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