Latest:Estimated Pressure 888 mb, winds 170 knts (314 kmph), position 490 nmi E/SE of Manila...Tracking W/NW....Warning as no chance of weakening before hitting The Philippines..
Dr. Jeff Master's Blog on Super Typhoon Haiyan
Super Typhoon Haiyran is one of the most intense tropical cyclones in world history, with sustained winds an incredible 190 mph (305 kmph), gusting to 230 mph (370 Kmph), 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 equalled 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.