Dr. Masters co-founded wunderground in 1995. He flew with the NOAA Hurricane Hunters from 1986-1990. Co-blogging with him: Bob Henson, @bhensonweather
By: Dr. Jeff Masters , 8:29 PM GMT on September 17, 2010
Hurricane Karl made landfall on the Mexican coast ten miles north of Veracruz at 1pm EDT today as a Category 3 hurricane with 115 mph winds. Veracruz was on the weak (left) side of Karl's eyewall, and did not receive hurricane force winds, except perhaps at the extreme northern edge of the city. Winds at the Veracruz Airport, located on the west side of the city, peaked at sustained speeds of 46 mph, gusting to 58 mph, at 11:54am local time. Radar out of Alvarado shows that Karl has kept its eyewall intact well inland, even as the storm moves into the high mountains east of Mexico City. Karl was the first major hurricane on record in the Bay of Campeche--the region of the Gulf of Mexico bounded by the Yucatan Peninsula on the east. There were two other major hurricanes that grazed the northern edge of the Bay of Campeche, Hurricane Hilda of 1955 and Hurricane Charley of 1951, but Karl is by far the farthest south a major hurricane has been in the Gulf of Mexico. Hurricane records go back to 1851, but Karl is a small storm and could have gotten missed as being a major hurricane before the age of aircraft reconnaissance (1945).
Figure 1. Tracks of all major hurricanes since 1851 near Mexico's Bay of Campeche. Karl is most southerly storm on record in the Gulf of Mexico. Image credit: NOAA Coastal Services Center.
With Karl's ascension to major hurricane status, we are now ahead of the pace of the terrible hurricane seasons of 2004 and 2005 for number of major hurricanes so early in the year. In 2005, the fifth major hurricane (Rita) did not occur until September 21, and in 2004, the fifth major hurricane (Karl) arrived on September 19. Wunderblogger Cotillion has put together a nice page showing all the seasons with five or more major hurricanes. The last time we had five major hurricanes earlier in the season was in 1961, when the fifth major hurricane (Esther) arrived on September 13. This morning we continue to have three simultaneous hurricanes, Hurricanes Igor, Julia, and Karl. This is a rare phenomena, having occurred only eight previous years since 1851. The last time we had three simultaneous hurricanes in the Atlantic was in 1998. That year also had four simultaneous hurricanes--Georges, Ivan, Jeanne and Karl--for a brief time on September 25. There has been just one other case of four simultaneous Atlantic hurricanes, on August 22, 1893. The year 2005 came within six hours of having three hurricanes at the same time, but the official data base constructed after the season was over indicates that the three hurricanes did not exist simultaneously.
Also remarkable this year is that are seeing major hurricanes in rare or unprecedented locations. Julia was the strongest hurricane on record so far east, Karl was the strongest hurricane so far south in the Gulf of Mexico, and Earl was the 4th strongest Atlantic hurricane so far north. This unusual major hurricane activity is likely due, in part, to the record Atlantic sea surface temperatures this year.
Figure 2. Hurricane Karl as seen by the MODIS instrument on NASA's Terra satellite at 12:20 pm CDT on Thursday, September 16, 2010. Image credit: NASA.
Figure 3. Radar image of Karl at landfall in Mexico. Image credit: Mexican Weather Service.
Impact of Karl on Mexico
Given that the Bay of Campeche coast has never experienced a hurricane as strong as Karl, its impact is likely to cause major damage to a 50-mile wide coastal area beginning ten miles north of Veracruz. Fortunately, the coast is not heavily populated there, and is not particularly low-lying, so the 12 - 15 foot storm surge will not be the major concern from Karl. The main concern will be flooding from Karl's torrential rains. The region has been hit by three Category 2 hurricanes over the past 55 years, and two of these storms caused flooding that killed hundreds. The strongest hurricanes in history to affect the region were Item in 1950, with 110 mph winds, Janet in 1955, with 100 mph winds, and Diana of 1990, with 100 mph winds. Flooding from Janet killed over 800 people in Mexico. and flooding from Diana killed at least 139 people. Karl's high winds are also a major concern, and these winds are likely to extensive damage.
The Hurricane Hunters just left Hurricane Igor, and found that the hurricane has continued to slowly weaken. On their last pass through the eye of Igor at 1:49 pm EDT, an Air Force hurricane hunter aircraft found a central pressure of 947 mb. The eyewall was missing a chunk on its southwest side. Top winds at the surface as seen by their SFMR instrument were barely Category 1 strength, 76 mph, though the aircraft did see 117 mph winds at 10,000 feet, which suggests the surface winds were probably of Category 2 strength, 105 mph.
Figure 4. Hurricane Igor as seen by the MODIS instrument on NASA's Terra satellite at 10:50 am EDT on Thursday, September 16, 2010. Image credit: NASA.
Igor's impact on Bermuda
Hurricane warnings are now flying for Bermuda, and tropical storm force winds will arrive at the island late Saturday night. Igor is a huge storm, and tropical storm force winds extend out 290 miles to the north of its center. As the hurricane moves north, it will expand in size, as it takes advantage of the extra spin available at higher latitudes due to Earth's rotation. By Saturday night, Igor's tropical storm force winds are expected to extend outwards 320 miles from the center. Igor will be moving at about 11 - 13 mph during the final 24 hours of its approach to Bermuda, so the island can expect a period of 39+ mph tropical storm force winds to begin near midnight Saturday night--a full 24 hours before the core of Igor arrives. Igor will speed up to about 15 mph as it passes the island near midnight Sunday night, and Bermuda's battering by tropical storm force winds will not be as long as Igor moves away, perhaps 10 hours long. Hurricane force winds will probably extend out about 70 miles from the center when the core of Igor reaches Bermuda, and the island can expect to be pounded by hurricane force winds for up to 6 - 8 hours. In all, Bermuda is likely to suffer a remarkably long 36-hour period of tropical storm force winds, with the potential for many hours of hurricane force winds. Long duration poundings like this are very stressful for buildings, and there is the potential for significant damage on Bermuda. However, buildings in Bermuda are some of the best-constructed in the world, and if Igor weakens to Category 2 strength, as appears likely, damage on the island may be just a few million dollars. According to AIR Worldwide, "Homes in Bermuda are typically one or two stories and constructed of 'Bermuda Stone,' a locally quarried limestone, or of concrete blocks. Roofs are commonly made of limestone slate tiles cemented together. Commercial buildings, typically of reinforced concrete construction, rarely exceed six stories. In both residential and commercial buildings, window openings are generally small and window shutters are common. These features make Bermuda's building stock quite resistant to winds, and homes are designed to withstand sustained winds of 110 mph and gusts of up to 150 mph."
Bermuda's hurricane history
Igor is similar in strength and projected track to Hurricane Fabian of 2003. Fabian hit Bermuda as a Category 3 hurricane with 120 mph winds. It was the most damaging hurricane ever to hit the island, with $355 million in damage. Fabian's storm surge killed four people crossing a causeway on the island. These were the first hurricane deaths on Bermuda since 1926. The most powerful hurricane on record to strike Bermuda was the Category 4 Havana-Bermuda Hurricane, which hit on October 22, 1926, with 135 mph winds. The hurricane sank two British warships, claiming 88 lives, but no one was killed on the island. The deadliest hurricane to affect the island occurred on September 12, 1839, when a Category 3 hurricane with 125 mph winds and an 11-foot storm surge hit, tearing off the roofs of hundreds of buildings and wrecking several ships. An estimated 100 people were killed (source: Encyclopedia of Hurricanes, Typhoons, and Cyclones, by David Longshore.)
Elsewhere in the tropics
A tropical wave off the coast of Africa, a few hundred miles south of the Cape Verdes Islands, is disorganized, but has the potential for some slow development over the next few days. The NOGAPS model develops this wave into a tropical depression 4 - 5 days from now. NHC is giving the wave a 10% of developing into a tropical depression by Sunday.
I'll have a new post on Saturday.
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