Typhoon Phanfone: unprecedented high winds - one of the three U.S. airmen washed away to sea

Tokyo is bracing for potentially unprecedented high winds as Typhoon Phanfone makes a beeline for the world's largest metropolitan area.

The typhoon's effects have already proven deadly. One U.S. airman has been found dead and two others are missing after waves caused by Typhoon Phanfone swept them away in Okinawa, according to a U.S. military official.

The eye of Phanfone is now just south of Japan's Pacific coast and moving east-northeast on a track that is likely to take it directly over Tokyo between 9 a.m. and noon Monday local time (8 and 11 p.m. EDT Sunday in the U.S.).

The Japan Meteorological Agency predicts sustained winds of 80 mph with gusts to 115 mph at that time. If such winds are measured in Tokyo, they would be the strongest ever recorded there.

According to JMA records, Tokyo's strongest sustained wind on record is 69.3 mph, recorded in a typhoon on Sept. 1, 1938. The city's strongest wind gust on record was 104.5 mph, recorded the same day.

An archived 1938 newspaper article from the says approximately 100 people died in the 1938 Tokyo typhoon.

Former Super Typhoon

At one point on Saturday, the U.S. military's Joint Typhoon Warning Center analyzed 150 mph winds within Phanfone, designating it super typhoon. The JTWC has since reduced its estimate of those winds slightly.

The Japan Meteorological Agency, the official regional center for tropical cyclone forecasts in the western North Pacific, indicated 10-minute sustained winds as high as 110 mph within Phanfone Saturday, but has lowered its estimates slightly as well. JMA's 10-minute wind speeds are usually lower than the 1-minute wind standard used by the U.S.

As of Sunday evening local time, the strongest winds are being felt in the Shikoku region of southern Japan. Earlier, the island of Kikaijima reported a peak gust of 42.2 meters per second (94.4 mph) at 5:45 a.m. Japanese time Sunday. (Japanese Standard Time, or JST, is 13 hours ahead of Eastern Daylight Time in the U.S.)

On Saturday, high winds were felt in the Daito Islands, which are part of Okinawa Prefecture. A wind gust of 101 mph was reported on Kitadaito (North Daito Island) before the wind observations were knocked offline. The other two observation sites on the islands, Minamidaito and Kyuto, gusted over 90 mph. Sustained winds maxed out at 57 to 64 mph at all three locations, safely below typhoon force, but the center of Phanfone was 120 kilometers (75 miles) away at its closest approach according to JMA bulletins.

Phanfone is now moving north and will eventually continue its right turn to move toward the north-northeast.

Although Phanfone is moving into an area of increasing vertical wind shear (changes in wind speed and direction with height) as well as cooler ocean waters, the storm will be slow to weaken and will still be a very intense system as it affects the larger islands of Japan.

Japan Impact

Phanfone has reached the western edge of a bubble of high pressure aloft -- and tropical cyclones often turn northward in those situations before eventually being forced northeastward by the prevailing upper-level westerlies, usually becoming post-tropical systems in the process.

The question remains exactly how sharp a turn Phanfone makes, and, therefore, what the exact track of the core circulation is.

Given Phanfone's large wind field and the latest forecast trends, Phanfone won't curve sharply enough to avoid at least some impacts from high winds over at least parts of central and eastern Honshu, and possibly western Honshu, Kyushu, Shikoku and the northern Ryukyu Islands.

Uncertainty remains, however, regarding Phanfone's intensity once it tracks near the Japanese mainland. Increased wind shear will induce weakening, but the longer the typhoon keeps its current intensity, the stronger it may still be once it tracks over Japan.

As a result, damaging winds may rake at least part of those areas this weekend, along with the threat of storm surge flooding in surge-prone areas.

Central and eastern Japan alone (the Kansai, Chubu and Kanto regions), including Kyoto, Kobe, Osaka, Nagoya and Tokyo, have a combined population of 85 million.

Here is a general timeline of when we expect peak winds (all times local):

- Kyushu, Shikoku, western Honshu: Through late Sun. night or early Mon. morning

- Central/eastern Honshu (Osaka, Nagoya, Tokyo): Later Sunday into Monday

Rainfall Threat

Regardless of the exact path of Phanfone, heavy rainfall is a given from this storm system.

The typhoon has already lashed the Daito Islands with 9 to 10 inches of rain, despite the lack of high terrain (the islands' top elevations are barely above 200 feet). As Phanfone approaches the mainland, with numerous mountains 5,000 to 10,000 feet high, the terrain will force the typhoon's moisture-laden air upward much more efficiently, wringing out very large amounts of rain.

The map above shows the RPM computer model forecast for rainfall through Tuesday morning local time. The map gives a general idea of where heavy rainfall may fall, but it's important to bear in mind that the official track forecast may differ from the forecast from any individual computer forecast model.

Additionally, Japan's steep terrain often leads to large variations in local rainfall that often aren't captured well by computer models. Indeed, in areas where winds blow perpendicular to the steep terrain, rainfall amounts could easily double what's shown above.

JMA forecast bulletins are predicting anywhere from 500 to 800 mm (roughly 20 to 32 inches) of rain in the Tokai region, including the Nagoya metropolitan area, Japan's third largest, with roughly the same population as Chicagoland. Other parts of Japan's Pacific coast could see generally 200 to 600 mm (roughly 8 to 24 inches) of rainfall.

Some of the areas in Phanfone's path saw historic rainfall from the one-two punch of Tropical Storm Nakri and Typhoon Halong in August. The city of Kochi had over 61 inches of rain in August, its wettest month in records dating back to 1886. The rural hamlet of Shigeto in the mountains of Kochi Prefecture picked up 94.41 inches of rain, crushing its previous all-time record for any calendar month by nearly 40 inches.

Track History

Phanfone was first declared a tropical depression early on September 29, local time, several hundred miles to the east of Guam, then tracked northwestward through the northern Mariana Islands, bringing locally heavy rain, gusty winds and high surf.

Phanfone strengthened from a Category 1 equivalent typhoon (75 mph estimated max winds) early on the evening of October 1, local time (Japan is 13 hours ahead of U.S. EDT) to a Category 4 equivalent typhoon (130 mph estimated max winds) just 24 hours later, a jump of 55 mph (or 50 knots) in 24 hours.

"Phanfone had the dreaded pinhole eye rarely seen in tropical cyclones," said The Weather Channel hurricane specialist Michael Lowry. "The eye was so small even our best microwave satellites had trouble seeing it."

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