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Bud a heavy rain threat for Mexico; 1-year anniversary of Joplin tornado

By: Dr. Jeff Masters, 11:07 AM GMT on May 22, 2012

Tropical Storm Bud intensified into a 40 mph storm this morning in the Eastern Pacific, off the coast of Mexico, and poses a significant flooding threat to the country late this week. The storm has been slow to organize due to its large size, as seen on satellite loops. But with favorable SSTs of 29 - 30°C and light to moderate wind shear in the 5 - 15 knots range expected along its path, Bud should steadily organize today and Wednesday, and become Hurricane Bud by Thursday. A trough of low pressure is expected to swing north of the storm late this week, turning Bud to the north towards the Mexican coast between Manzanillo and Acapulco. However, the trough of low pressure may not be strong enough to bring Bud ashore, and the storm could linger near the coast for several days, potentially deluging the coast with very heavy rains capable of triggering dangerous flash floods and mudslides, beginning on Friday.

Figure 1. Morning satellite image of Bud.

Record earliest date for formation of the season's second named storm
Bud is the second named storm to form in the Eastern Pacific in 2012--Tropical Storm Aletta, which formed on May 15, was the first. Bud's appearance on May 21 marks the earliest date since record keeping began in 1949 for formation of the season's second named storm. The previous record was set in 1984, when the second named storm formed on May 29. Only two other years have had two named storms in May in the Eastern Pacific--2007 and 1956, which both had the second named storm of the year form on May 30. If Bud ends up making landfall in Mexico as a hurricane, it would be only the second Eastern Pacific May hurricane on record to hit Mexico. The other was Hurricane Agatha of May 24,1971, which hit the same stretch of coast that Bud is threatening. Agatha made landfall as a Category 2 hurricane about 45 mi (75 km) from Zihuatanejo, Mexico. The village of Playa Azul was hard hit by the storm, with up to half of the village's homes destroyed. Ocean temperatures this year in the region where Aletta and Bud formed are only slightly above average, so the large scale atmospheric patterns are probably more to blame for this year's exceptionally early start to hurricane season in the Eastern Pacific.

Figure 2. True-color visible satellite image of Alberto taken by the Aqua satellite at 2 pm EDT Monday May 21, 2012. Image credit: NASA.

Alberto headed out to sea
Tropical Depression Alberto is racing northeastwards out to sea, and has been substantially weakened by very high wind shear of 50 knots and passage over cool ocean waters of 24°C (75°F). Alberto will not trouble any land areas, and does not have long to live before being completely dismantled by the high wind shear.

Figure 3. Aerial view of damage from the May 22, 2011 Joplin, Missouri tornado. Image credit: Wikipedia.

One-year anniversary of the Joplin, Missouri EF-5 tornado
May 22 marks the 1-year year anniversary of the deadly Joplin Missouri tornado. The massive EF-5 tornado with winds in excess of 200 mph mowed a 14-mile path of destruction up to one mile wide across the southern portion of the city. The tornado killed 161 people--the highest death toll from a U.S. tornado since 1947, and the seventh deadliest tornado in U.S. history. The tornado did $3 billion in damage, making it the most expensive tornado in world history. The death toll from the tornado undoubtedly would have been higher had the National Weather Service not issued a tornado warning a full 24 minutes in advance of the tornado. This is nearly double the average tornado warning lead time of thirteen minutes.

The most remarkable audio I've ever heard of people surviving a direct hit by a violent tornado was posted to Youtube by someone who took shelter in the walk-in storage refrigerator at a gas station during the Joplin tornado. There isn't much video.

Video 1. Video of the Joplin, Missouri tornado of May 22, 2011, entering the southwest side of town. Filmed by TornadoVideos.net Basehunters team Colt Forney, Isaac Pato, Kevin Rolfs, and Scott Peake.

Jeff Masters


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