After a quick start to the 2007 Atlantic Hurricane Season with two named storms by the end of the first day on June 1st, the tropics became dormant for almost two full months. Even after the third storm of the season, Tropical Storm Chantal formed, the region was still waiting to break out, especially after a relatively quiet season in 2006. Hurricane Dean would be that storm to break the Atlantic Tropics out of its slump. Dean, which was born as a depression on August 13th, not only became the first hurricane of the 2007 Atlantic Season, but it also was the first major hurricane, seventh Category Five system in the past five years, and the third strongest Atlantic storm to ever make landfall. Dean, which ended up as the ninth strongest storm ever recorded in the entire Atlantic Basin, would make two landfalls in Mexico after brushing the southern tip of Jamaica.
Towards the end of the first week in August 2007, the tropics are starting to show signs of heating up. None of this is more evident than in the Eastern Atlantic, where a tropical wave has been moving to the West. It goes through some ups and downs for a few days, but by Monday, August 13th, the disturbance is looking more like it will become a depression. So, in the middle of the morning, during the 11:00 AM EDT Advisory, the National Hurricane Center classifies the tropical wave as the fourth depression of the seasons. According to the first discussion on the system, deep convection had persisted for about a half day, and there are estimates of 30 knot winds from an analysis. For approximately 24 hours, TD #4 maintains its intensity, but is unable to get any stronger because the system is moving very rapidly to the west thanks to a strong easterly flow from a deep layered subtropical ridge.
Finally, on Tuesday, August 14, 2007, the storm gets better organized and strong enough to be reclassified as the fourth named storm of the 2007 season. Maximum sustained winds grow to 40 miles per hour while gusts are in excess of 50 miles per hour. Minimum central pressure in the fledgling storm has dropped to 1004 millibars, or 29.65 inches of Hg (Mercury). But, the strong easterly flow continues to have the young storm racing to the West at 23 miles per hour some 1,500 miles to the east of the Lesser Antilles. The dominant subtropical ridge to the north of Dean in the Central Atlantic is pushing the storm so fast that there is a fear that the storm will not be able to develop. The strong flow hinders better organization and further development for about 12 hours until the storm begins to finally slow down on Tuesday evening. At that point, Dean strengthens to have sustained winds in excess of 50 miles per hour, and gusts up to 65 miles per hour while pressure has dropped to 1000 millibars, or 29.53 inches of Hg (Mercury).
The slow down on Tuesday evening, August 14th, is critical. It gives Dean a chance to catch its breath, and intensify in the warming waters of the Tropical Atlantic, which are just beginning to hit their stride. By mid-morning on August 15th, Dean has strengthened to have maximum sustained winds of 60 miles per hour, gusts up to 70 miles per hour, and a minimum central pressure down to 29.44 inches of Hg, or 997 millibars. At this point in time, Tropical Storm Dean is very small in size with its wind field expanding only 50 miles from the center of circulation. However, over the coming days, Dean would grow into a huge monstrous Category Five Hurricane on the Saffir-Simpson Scale with a wind field that was 235 miles in diameter including hurricane force winds that extended some 60 miles from the eye, and tropical storm force winds that reached some 175 miles. Maximum sustained winds reached 165 miles per hour with gusts as high as 200 miles per hour. Barometric pressure had bottomed out at 906 millibars, or 26.75 inches of Hg. Slamming into the Southern Yucatan some 40 miles to the Northeast of Chetumal, Mexico at 5:00 AM EDT on August 21, 2007, Dean had joined a class only occupied by Hurricane Gilbert in 1988 and the Labor Day Hurricane of 1935. It would end up being responsible for some 45 deaths and approximately $2 billion in damage.
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Long before Dean became the first Category Five Hurricane since the historic and unprecedented year of 2005, and the seventh such storm since 2003, it moved through the Lesser Antilles as a strong Category One system with 90 mile per hour winds, gusts reaching 110 miles per hour. Pressure was down to 979 millibars, or 28.91 inches of Hg (Mercury). It was just 11:00 AM EDT on Thursday, August 16th, and the fledgling hurricane was gathering momentum some 350 miles east of Barbados, or 455 miles east of Martinique. Three hours later, Air Force Reconnaissance aircraft finally reaches Dean, and begins investigating and researching it. As of the 2 PM EDT Advisory on August 16th, the storm's vital signs remained stable. However, it wouldn't be that way for long. Within three hours, Dean becomes a Category Two storm with 100 mile per hour winds as it rapidly approaches the Lesser Antilles. Twelve hours later, it was moving through the Windward Islands, passing near St. Lucia and Martinique during the early morning hours of August 17th.
In the next eight hours, Dean underwent an initial stage of rapid intensification as its winds grew to 125 miles per hour with gusts as high as 155 miles per hour, and a minimum central pressure of 961 millibars, or 28.35 inches. Not stopping there, Dean would continue to get stronger, and tighten the rotation around its calm eye. The storm would drop yet another 43 millibars in the next 33 hours for a total drop of 58 millibars over a span of 39 hours. Winds grew to 150 miles per hour with gusts roaring up to 185 miles per hour. The eye has narrowed to just ten nautical miles, which is a sign of significant strength and power. Dean's wind field has grown to 265 miles including a range of 60 miles from the eye for hurricane force winds while tropical storm force winds reached some 205 miles. Barometric pressure had fallen to 918 millibars, or 27.11 inches. Dean was now ranked as high as Hurricane Hugo from 1989, and behind Hurricane Isabel on the all time storms list.
But now, the storm had to deal with its own demons brought on by the process of eyewall replacement. In addition, Jamaica laid before it as an island that had not experienced a direct hit from a hurricane since Gilbert in September 1988. At that time, the island was devastated by winds as high as 140 miles per hour, a strong and powerful prelude to its raging 180 mile per hour winds and over 200 mile per hour gusts that Gilbert brought into the Yucatan days later. Thankfully, Dean would just skirt the very tip of the island with the strongest winds from its eyewall just brushing the area south of Jamaica. Nevertheless, the island nation still was battered by the storm. See storm footage from Red Hills as well as Clarendon courtesy of users posts to the Weather Channel web site. As Dean moves south of Jamaica and the nearby Cayman Islands, its sustained winds slacken off a bit to just 145 miles per hour while its pressure rises to 930 millibars, or 27.46 inches of Hg. View video footage of the storm's impact on Grand Cayman. Slightly staggered by the evening of August 19th, Dean regains itself, and begins re-strengthening.
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Over the next thirty-three hours, pressure would fall another 24 millibars, and its winds would gradually increase to 165 miles per hour just as the storm was coming ashore in the area of Costa Maya, or Majahual on the morning of August 21st. Barometric pressure stood at 906 millibars, or 26.75 inches of Hg (Mercury). Dean was coming ashore as the third strongest hurricane ever to make landfall in the Western Hemisphere behind Gilbert and the Labor Day Hurricane of 1935. View storm footage from Belize City in Belize. It also earned the ranking of ninth on the all time list ahead of Hurricane Ivan (2004), and behind monsters such as Hurricane Mitch (1998) and Hurricane Camille (1969). Hurricane Dean had become the seventh Category Five Hurricane in the last five years, and eighth in the last ten. After some 22 months of slumber, the Atlantic Basin was alive and raging again. Thank goodness, the United States coastline was not in the crosshairs.
Hurricane Dean would weaken as it encountered the high plateau of the Yucatan. Nevertheless, it maintained hurricane intensity throughout its trip across the Peninsula. Emerging out into the Bay of Campeche region of the Gulf of Mexico in the late afternoon of August 21st, the once powerful hurricane is just a minimal storm with 80 mile per hour winds while its pressure rose to 970 millibars, or 28.64 inches of Hg. Staying well to the south, and away from any United States coastal areas, Dean thrived again in the very warm waters of the Southern Gulf. Over the next 20 hours, the storm grew to a Category Two system again by gaining one mile per hour in wind speed during the period. Pressure actually rose to 979 millibars, or 28.91 inches of Hg (Mercury). At 12:30 PM EDT, the hurricane finally made landfall for the second time in the coastal town of Gutierrez Zamora along the Mexican Gulf Coast some 40 miles to the South-Southeast of Tuxpan. As Dean moved further inland, it gradually weakened to a remnant low thanks to the presence of the rugged terrain of the Sierra Madre. Despite dying a slow death thanks to the friction of the high mountains, Dean's remnants still dumped a lot of rain over the region due to the orographic lifting of the moist, tropical air over the land barriers.
A shell of its former self, Dean's remnants hobbled their way across Mexico, and even brought some high humidity and storminess to parts of Southern California including San Diego, which is known for a very comfortable and enjoyable climate. Meanwhile, in the storm's wake, the numbers of dead began to grow as well as the damage estimates. As of August 23rd, insurance companies went through their statistical models, and came up with a range of damage from $1.5 billion to nearly $2 billion dollars. As many as 20 people were dead throughout the Caribbean including nine in Haiti, six in the Dominican Republic (see footage of giant waves along Dominican Republic coast), two in Dominica, two in Jamaica, and one in St. Lucia. Days later, that toll would approach fifty as another 25 were discovered dead in Mexico. Industries were beat up by the storm as well including Mexico's national oil company PEMEX, which has oil refineries in the Bay of Campeche region while Aluminum giant, Alcoa, stationed out of Pittsburgh, Pennsylvania, took a hit as well when aluminum plants in Jamaica were taken offline by the storm. Those economic effects added to the chaos ravaging the global markets caused by a subprime mortgage industry in disarray, and a credit crunch that has had banks and financial companies scrambling to prevent disaster. It goes to show that today's global economy can go into turmoil with the slightest hiccup.
With the coming and going of Hurricane Dean as well as the development of Tropical Storm Erin, the Atlantic now had five named storms, one hurricane, and one major hurricane on the 2007 season. Dean's formation could only be the tip of the iceberg as the peak of the season approaches. The statistical height of the Atlantic season is September 10th, and the development of this powerful hurricane heralded the beginning of the most terrifying part of every hurricane season, the Cape Verde Season, when storms begin to form off the coast of Africa. These storms are often the most powerful, deadliest, and devastating.
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