Super Typhoon Dolphin

Super Typhoon Dolphin Becomes Earth's 5th Category 5 Storm of 2015

Geoff Masters

Wunderground,

17 May, 2015

Super Typhoon Dolphin intensified into a Category 5 storm with 160 mph winds and a central pressure of 925 mbat 2 pm EDT Saturday May 16, becoming Earth's fifth Category 5 storm of the year. Dolphin hung on to Category 5 strength for twelve hours before increasing wind shear helped knock the storm down to a Category 4 storm with 150 mph winds by Sunday morning. The eye of Dolphin passed through the channel between the islands of Guam and Rota Friday morning when the storm was at Category 2 strength with sustained winds of 110 mph. Guam experienced the weaker southern eyewall, and Rota saw the stronger northern eyewall. Andersen Air Force Baseon Guam experienced sustained winds as high as 84 mph at 7:55 pm local time Friday, with a peak gust of 106 mph. Rainfall amounts tallied 9.30" in a 12-hour period. Dolphin knocked out power and damaged some homes, but the islands escaped serious destruction; Guam and Rota were very lucky that Dolphin waited a day to put on its intensification into a Category 5 storm. Satellite loops show a very impressive, well-organized system with a large ring of intense eyewall thunderstorms with very cold clouds tops, and prominent 28-mile diameter eye. A strong trough of low pressure has recurved the storm to the north, and Dolphin may pass close enough to Iwo Jima on Tuesday to bring that island typhoon conditions. 

Figure 1. Still frame from 05 UTC May 16 2015, taken from a remarkable super high-resolution (every 2.5 minutes at 0.5 km) visible satellite loop of Super Typhoon Dolphin on Saturday morning, May 16, put together by The University of Wisconsin CIMSS group, using imagery from the new Japanese Himawari-8 satellite. At the time, Dolphin was an intensifying Category 4 super typhoon with 150 mph winds. More info and hi-res infrared loops can be found at the CIMSS satellite blog.
An unusual number of Category 5 storms so far in 2015

May 16 is exceptionally early to be getting our third Category 5 storm of the year in the Northwest Pacific. The global record for Category 5 storms is held by the El Niño year of 1997, which had twelve Category 5 storms--ten of them in the Northwest Pacific. The third Cat 5 of 1997 in the Northwest Pacific occurred on July 22, so we are more than two months ahead of that year's record pace. Dolphin is also the earliest-appearing 7th named storm of the Northwest Pacific's typhoon season; the previous record was on May 19, 1971. Super Typhoon Dolphin is already Earth's fifth Category Five storm this year, which is an unusually large number of these high-end tropical cyclones for so early in the year. Earth averaged just 4.6 Category 5 storms per year between 1990 - 2014, so we've already exceeded our average for an entire year; 2015 already has the 6th most Category 5 storms for any year in the past 26 years (reliable satellite records of Southern Hemisphere tropical cyclones extend back to 1990, so we only have about a 26-year period of decent records for global Category 5 tropical cyclones.) The majority of these storms occur during the July - November peak of the Northern Hemisphere's tropical cyclone season, with 59% of all Cat 5s occurring in the Northwest Pacific, so it is likely we will see several more Cat 5s this year. The early and violent start to 2015 typhoon season is due, in part, to exceptionally warm ocean temperatures in the typhoon breeding region between 5 - 10°N near the Date Line. These temperatures have been over 2°C (3.6°F) above average in recent months, due to a strengthening El Niño event. 
The other four Category 5 storms of 2015:

Cat Five #1, Southwest Indian. Tropical Cyclone Eunice as seen by the MODIS instrument at 05:30 UTC January 30, 2015, when the storm was at peak intensity (160 mph winds, 900 mb pressure.) Eunice was the 3rd strongest cyclone ever observed in the Southwest Indian Ocean by pressure, and the strongest by winds. Fortunately, Eunice affected only ocean areas in the South Indian Ocean. 

Cat Five #2, Southeast Pacific. Tropical Cyclone Pam near peak intensity (165 mph winds, 896 mb pressure), as seen by the VIIRS instrument on the Suomi satellite at 10:42 am EDT March 13, 2015, just southeast of Efate Island, where the capital of Vanuatu, Port Vila, lies. Pam killed 16 people and did $250 million in damage to the island nation of Vanuatu, making it the 2nd most expensive disaster in their history (the most expensive, according to EM-DAT: Cyclone Eric of 1985, which did $173 million in damage in 1985 dollars, or $377 million 2015 dollars.) Pam was the third most intense storm in the entire Southern Hemisphere by central pressure, only after Cyclone Zoe of 2002 and Cyclone Gafilo of 2004. Pam is tied with Cyclone Orson and Cyclone Monica for having the strongest sustained 10-minute average winds of any cyclone on record in the Southern Hemisphere. Image credit: @NOAASatellites.

Cat Five #3, Northwest Pacific. Super Typhoon Maysak as seen from the International Space Station at approximately 6 pm EDT Tuesday March 31, 2015 (just after dawn local time.) At the time, Mayask was at peak intensity, with sustained winds of 160 mph (as estimated by the Joint Typhoon Warning Center) and a central pressure of 905 mb (as estimated by the Japan Meteorological Agency.) Maysak was the strongest typhoon ever observed in the Northwest Pacific prior to April, and one of only three Category 5 typhoons ever observed in the Northwest Pacific so early in the year. Maysak killed 9 and did $8.5 million in damage to several small islands in the Federated States of Micronesia, which it struck at Category 5 strength on March 31. The nine people killed by the storm made it Micronesia's second deadliest storm in recorded history, according to EM-DAT. Their deadliest disaster was Category 4 Typhoon Chataan, which dumped 19.90" (506 mm) of rain in 24 hours on Chuuk, causing landslides that killed 47 people. Maysak is the 2nd most expensive disaster in Micronesia's history; the most expensive was Category 1 Typhoon Nina, which did $6 million (1987 dollars) in damage on November 21, 1987.

Cat Five #4, Northwest Pacific. Super Typhoon Noul as seen by the new Japanese Himawari-8 satellite at 00:50 UTC May 10, 2015. At the time, Noul was a peak-strength Category 5 storm with 160 mph winds and a 915 mb central pressure. Noul hit northeast Luzon in the Philippines on May 10, killing two and causing less than $1 million in damage. Noul was the third strongest typhoon on record for so early in the year. The only stronger ones were Super Typhoon Amy of 1971, which deepened to 890 mb on May 2, and Super Typhoon Iris of 1951, which hit 909 mb on May 3. Image credit: The University of Wisconsin/CIMSS, which put together a remarkable hi-res satellite animation of the storm from the Himawari-8 satellite (which is still in check-out mode.) 
Jeff Masters