Super Typhoon Haiyan Finishes Pounding the Philippines, Headed for Vietnam

After spending 48 hours at Category 5 strength, the strongest landfalling tropical cyclone in world history, Super Typhoon Haiyan, has finally weakened to a Category 4 storm. With top sustained winds of 155 mph, Haiyan is still an incredibly powerful super typhoon, but has now finished its rampage through the Central Philippine Islands, and is headed across the South China Sea towards Vietnam. Satellite loops show that Haiyan no longer has a well-defined eye, but the typhoon still has a huge area of intense thunderstorms which are bringing heavy rains to the Central Philippines. I've never witnessed a Category 5 storm that made landfall and stayed at Category 5 strength after spending so many hours over land, and there are very few storms that have stayed at Category 5 strength for so long.


Figure 1. Super Typhoon Haiyan approaching the Philippines, as seen by the Japan Meteorological Agency's MTSAT at 0630Z on November 7, 2013. At the time, Haiyan had maximum sustained winds of 175 mph. Image credit: NOAA Environmental Visualization Laboratory.

Haiyan's place in history
Haiyan hit Guiuan, on the Philippine island of Samar, at 4:40 am local time (20:40 UTC) November 8, 2013. Three hours before landfall, the Joint Typhoon Warning Center (JTWC) assessed Haiyan’s sustained winds at 195 mph, gusting to 235 mph, making it the 4th strongest tropical cyclone in world history. Satellite loops show that Haiyan weakened only slightly, if at all, in the two hours after JTWC’s advisory, so the super typhoon likely made landfall with winds near 195 mph. The next JTWC intensity estimate, for 00Z UTC November 8, about three hours after landfall, put the top winds at 185 mph. Averaging together these estimates gives a strength of 190 mph an hour after landfall. Thus, Haiyan had winds of 190 - 195 mph at landfall, making it the strongest tropical cyclone on record to make landfall in world history. The previous record was held by the Atlantic's Hurricane Camille of 1969, which made landfall in Mississippi with 190 mph winds.

According to the official "best track" records from the Joint Typhoon Warning Center, here are the strongest tropical cyclones in world history:

Super Typhoon Nancy (1961), 215 mph winds, 882 mb. Made landfall as a Cat 2 in Japan, killing 191 people.
Super Typhoon Violet (1961), 205 mph winds, 886 mb pressure. Made landfall in Japan as a tropical storm, killing 2 people.
Super Typhoon Ida (1958), 200 mph winds, 877 mb pressure. Made landfall as a Cat 1 in Japan, killing 1269 people.
Super Typhoon Haiyan (2013), 195 mph winds, 895 mb pressure. Made landfall in the Philippines at peak strength.
Super Typhoon Kit (1966), 195 mph winds, 880 mb. Did not make landfall.
Super Typhoon Sally (1964), 195 mph winds, 895 mb. Made landfall as a Cat 4 in the Philippines.

However, it is now recognized (Black 1992) that the maximum sustained winds estimated for typhoons during the 1940s to 1960s were too strong. The strongest reliably measured tropical cyclones were all 5 mph weaker than Haiyan, with 190 mph 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. Haiyan's winds were estimated using only satellite images, making its intensity estimate of lower confidence. 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 18 UTC (1 pm EST) November 7, 2013. This would make Haiyan the 12th strongest tropical cyclone on record globally, as far as lowest pressure goes.


Figure 2. Damage from Super Typhoon Haiyan in Legazpi city, Albay province, Nov. 8, 2013, about 325 miles south of Manila, Philippines. (Twitter/Ritchel M. Deleon)

Massive damage in the Philippines
Wind damage on the south shore of Samar Island in Guiuan (population 47,000) must have been catastrophic, perhaps the greatest wind damage any place on Earth has endured from a tropical cyclone in the past century. A massive storm surge must have also caused great destruction along a 20-mile swath to the north of where the eye hit, where Project NOAH was predicting a 17’ (5.3 meter) storm tide. Wind and storm surge damage were heavy in Tacloban, population 221,000, the capital of the province of Leyte, according to preliminary media reports. Much of Tacloban is at elevations less than ten feet, and several videos posted on YouTube showed a storm surge of at least ten feet moving through the city. The northern (strong) part of Haiyan’s eyewall made a direct hit on the city. Storm Chaser Jim Edds was in Tacloban, and reported that at least ten crewed boats were in the harbor, attempting to ride out the storm. Haiyan’s winds, rains, and storm surge have caused widespread devastation throughout the Central Philippines, though we do not yet have reports from the worst-hit portions of the disaster zone, including the south shore of Samar Island. Fortunately, the storm’s fast forward speed of 25 mph cut down the amount of rain the storm dumped, compared to typical typhoons that affect the Philippines. Hopefully, this will keep the death toll due to flash flooding relatively low. Flash floods are usually the biggest killer in Philippine typhoons.


Figure 3. Predicted rainfall from the 06Z November 8, 2013 run of the HWRF model, for the 96-hour period ending at 06Z November 12, 2013. A 100-mile wide swath of 8 - 16 inches of rain (medium dark red colors) as well as a 30-mile wide swath of 16 - 24" (dark red colors) is predicted to affect Vietnam and Laos. Rains of this magnitude are likely to cause a top-five most expensive natural disaster in both nations. Image credit: NOAA/NCEP/EMC.

Haiyan an extremely dangerous storm for Vietnam and Laos
Haiyan will steadily decay over the next two days, due to colder waters and higher wind shear. However, it will still likely be a formidable Category 1 or 2 typhoon when it makes landfall in Vietnam near 06 UTC Sunday. Haiyan is expected to begin recurving to the northwest as it makes landfall, which means that a long 100+ mile stretch of the Vietnam coast will receiving the punishing winds and peak storm surge of the strong northern portion of the typhoon. With part of its circulation still over water, Haiyan will be able to pull in a huge amount of moisture that will create prodigious rains over Vietnam and Laos. I expect that the 12+ inches of rain that the storm will dump on those nations will make it a top-five most expensive natural disaster in their history.

Links
Visible satellite landfall loop from the Korean COMS-1 satellite, courtesy of Scott Bachmeier of the University of Wisconsin CIMSS group.
Damage videos from Tacloban from Marcjan Maloon
Twitter updates from Japan meteorologist Robert Speta.


Video 1. Damaging winds and a potent storm surge from Super Typhoon Haiyan are captured in this video from the capital of Leyte Province, Tacloban, which received a direct hit from Haiyan. Thanks to wunderground member GatorWX for posting this in my blog comments.

Jeff Masters