Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.
By: Dr. Jeff Masters , 4:41 PM GMT on November 07, 2013
Super Typhoon Haiyan is one of the most intense tropical cyclones in world history, with sustained winds an incredible 190 mph, gusting to 230 mph, said the Joint Typhoon Warning Center in their 15 UTC (10 am EST) November 7, 2013 advisory. Officially, the strongest tropical cyclone in world history was Super Typhoon Nancy of 1961, with sustained winds of 215 mph. However, it is now recognized (Black 1992) that the maximum sustained winds estimated for typhoons during the 1940s to 1960s were too strong. Since 1969, only three tropical cyclones have equaled Haiyan's 190 mph sustained winds--the Western Pacific's Super Typhoon Tip of 1979, the Atlantic's Hurricane Camille of 1969, and the Atlantic's Hurricane Allen of 1980. All three of these storms had a hurricane hunter aircraft inside of them to measure their top winds, but Haiyan's winds were estimated using only satellite images, making its intensity estimate of lower confidence. Some interpretations of satellite intensity estimates suggest that there may have been two super typhoons stronger than Tip--Super Typhoon Gay of 1992, and Super Typhoon Angela of 1995. We don't have any measurements of Haiyan's central pressure, but it may be close to the all-time record of 870 mb set by Super Typhoon Tip. The Japan Meteorological Agency estimated Haiyan's central pressure at 895 mb at 12 UTC (7 am EST) November 7, 2013. Haiyan has the most spectacular appearance I've ever seen on satellite loops, with a prominent eye surrounded by a huge, impenetrable-looking mass of intense eyewall thunderstorms with tops that reach into the lower stratosphere. With landfall expected to occur by 21 UTC (4 pm EST) on Thursday, Haiyan doesn't have time to weaken much before landfall, and will likely hit the Philippines at Category 5 strength.
Figure 1. MODIS satellite image of Super Typhoon Haiyan taken at 4:25 UTC November 7, 2013. At the time, Haiyan was a Category 5 storm with top winds of 175 mph. The Philippines are visible at the left of the image, and the Caroline Islands at the lower right. Image credit: NASA.
Haiyan will be the third Category 5 typhoon to make landfall in the Philippines since 2010. In 2010, Super Typhoon Megi peaked at 180 mph winds just east of Luzon Island in the Philippines, and made landfall in the Philippines as a Category 5 storm. Megi's landfall was proof that the Philippines can withstand a strike by a Category 5 storm without a catastrophe resulting, as Megi killed only 35 people, and did $276 million in damage. However, the last Category 5 storm to hit the Philippines--Super Typhoon Bopha, which hit the southern Philippine island of Mindanao on December 3, 2012--did cause a catastrophe. The typhoon left 1901 people dead, mostly on the island of Mindanao, making Bopha the 2nd deadliest typhoon in Philippine history. With damages estimated at $1.7 billion, Bopha was the costliest natural disaster in Philippines history at the time.
Figure 2. Super Typhoon Megi as seen by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite at 10:35 a.m. Philippine Time (02:35 UTC) on October 18, 2010. Megi was bearing down on Luzon Island in the Philippines as a Category 5 storm with 170 mph winds. Megi killed 35 and did $276 million in damage, making it the 6th most expensive typhoon in Philippines history. Image credit: NASA Earth Observatory.
Haiyan's deadliest danger: heavy rains, high winds
The deadliest threat from Philippine typhoons is usually heavy rains, since the islands are very mountainous, leading to very high rainfall amounts capable of causing dangerous flash floods and mudslides. Deforestation of the mountainous slopes has contributed to this problem in recent decades. The latest rainfall forecast from the 06Z November 7, 2013 run of the HWRF model is not encouraging. A 50-mile wide swath of 8+ inches of rain is predicted to cross the Central Philippines. The soils are already very wet from the heavy rains that Tropical Depression 30 dumped over the region on Monday, so the rains from Haiyan will runoff quickly and create life-threatening flooding. Haiyan's winds are also a huge concern, particularly in Tacloban, population 221,000, the capital of the province of Leyte. Tacloban will likely receive a direct hit, and I expect the sustained winds from Haiyan will be at Category 4 strength in the city.
Figure 3. Predicted rainfall from the 06Z November 7, 2013 run of the HWRF model, for the 108-hour period ending at 18Z November 11, 2013. A 50-mile wide swath of 8+ inches of rain (medium dark red colors) is predicted to cross the Central Philippines and Northern Vietnam. This is likely an underestimate of the rains, since Haiyan is now stronger than what the HWRF model was predicting at 06Z. Image credit: NOAA/NCEP/EMC.
Haiyan a serious storm surge threat
Haiyan will cause much higher storm surge damage than is typical for a Philippines typhoon. A worst-case scenario now appears unlikely, as the current forecast track will keep the storm surge from building into the funnel-shaped Leyte Gulf, which comes to a point in Tacloban, population 221,000, the capital of the province of Leyte. Much of Tacloban is at elevations less than ten feet, and storm surge forecasts made earlier today by the Philippines' Project NOAH were calling for a storm tide (the combined height of the surge plus the tide) of 15' (4.5 meters) in Tacloban. With Haiyan now expected to push the waters out of Leyte Gulf upon approach, the storm tide will likely not get that high in Tacloban. The greatest storm tide will occur to the east of Tacloban on the east shore of Samar Island, where a massive 17' (5.3 meter) storm tide was predicted by Project NOAH. Many locations in the Central Philippines are expected to see storm tides in excess of 8' (2.5 meters), after Haiyan crosses Leyte and Samar Islands. To give you some idea of the size and power of Haiyan, a storm tide of 4.5' (1.4 meters) is predicted in the capital of Manila, even though the typhoon is expected to pass 180 miles to the south of the city. An experimental storm surge forecast from the European Commission's Joint Research Centre HyFlux2 model calls for a peak storm surge of 7.5 feet (2.3 meters) from Haiyan. This model has not been verified for the Philippines, and I expect the storm surges from a 190 mph Category 5 typhoon will be more in line with what Project NOAH is predicting. Here are the storm tide forecasts, which are updated every six hours on the the Philippines' Project NOAH website:
Figure 4. Elevation map of Leyte Island (left) and Samar Island (top) in the Philippines. Much of the capital of Leyte, Tacloban, is at an elevation less than 4 meters (13'), red to dark red colors. The predicted path of Haiyan’s eye in the 15 UTC November 7, 2013 Joint Typhoon Warning Center advisory is shown. Image credit: Globalwarmingart.com.
Haiyan the fifth named storm to hit the Philippines in 2013
Haiyan will be the fourth typhoon and fifth named storm to hit the Philippines this year. The others were:
Tropical Storm Rumbia, which hit the island of Samar on June 29 as a tropical storm, killing six.
Typhoon Nari, which hit Luzon on October 11 as a Category 3 typhoon with 115 mph winds, killing five.
Typhoon Utor, which hit Luzon on August 12 as a Category 4 typhoon with 140 mph winds, killing fourteen and causing $25 million in damage.
Typhoon Krosa, which hit northern Luzon on October 31 as a Category 2 typhoon with 105 mph winds, killing five and doing $5 million in damage.
Storm Chaser James Reynolds on Twitter, from Tacloban, Leyte.
Storm Chaser Jim Edds on Twitter, from Tacloban, Leyte.
Webcam in Malay, Philippines
Webcam in Boracay, Philippines
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