#3352

Typhoons - wind, rain and lot more!

Typhoon 101 - an introduction

It would be fair to call Japan at once a country blessed by natural beauty and cursed by natural disasters. Sitting on the famed “Ring of Fire”, the country hosts some spectacular and dangerous volcanoes, as well as the all-too-infamous and frequent earthquakes, some of which can wreak unimaginable devastation.
Every summer, the warm waters of the southern Pacific Ocean also give rise to another form of danger which visits the Japanese homeland often: typhoons. An average of four to six typhoons a year batter various parts of the Japanese homeland. Typhoon tracks can cover almost every conceivable path across and through the country’s islands, but the most common route is from Okinawa in the south, across Kyushu and Shikoku in the southwest, over the Pacific side of Honshu, then brushing the northernmost isle of Hokkaido before blowing out to the northern Pacific Ocean and to their ultimate death near the Bering Sea.
Japan’s roughly north/south orientation allows maximum exposure to all of the forces of a typhoon and an interested observer can see the changes of a typhoon’s life cycle as it progresses northward. On a typical path across the country, Okinawa and southern Kyushu will normally bear the brunt of a typhoon, where the storm, sucking in energy from the warm waters surrounding the area, will hit the islands with full force. Winds will frequently top 200kph. From there, moving over Kyushu and Shikoku, the storm will then begin to lose strength rapidly. Cities further up the coast, such as Osaka and Nagoya will get heavy wind and rain, but there is little real threat of damage. By the time a typhoon reaches Tokyo, it frequently is reduced to a long thunderstorm, with some local heavy winds, but little else. Anywhere north of the Tokyo area, then, will receive a good amount of rain, and the winds will have died down to little more than a brisk breeze.

So, what is a typhoon? Strictly speaking, typhoons are classified as organized, rotating storms with sustained winds of over 118 km/h. A storm under that level may get a tropical depression or tropical storm designation. Within the “typhoon” classification, there are three recognized subdivisions of typhoons: typhoons (naturally), severe typhoons, and super typhoons. A typhoon has wind speed of 118-149 km/h, a severe typhoon has winds of at least 150 km/h, and a super typhoon has winds of at least 190 km/h. While that seems to be an enormous leap in magnitude, don't let it overwhelm you. Consider how quickly Typhoon No. 8 (more on naming below) died out this past July (2014).
Typhoon No. 8, also known as Typhoon Neoguri, packed super typhoon level winds when it hit Okinawa on July 8th 2014, causing widespread damage to the prefectures islands. Media both in Japan and abroad noted its power and warned of its destructiveness as it turned toward Kyushu, hyping it as the "super typhoon of the century/decade" (depending on your source). However, by the time it hit Tokyo on July 11th, it had lost most of its power, and was actually demoted to a tropical storm. Its ferocious 200 km/h winds had petered down to a mere 80 km/h upon arrival in Tokyo, making the system a little more than a tempest in the proverbial teapot. In short, the so-called super typhoon of the century, which truly lashed Okinawa with an unmerciful severity, had, in 72 hours, been reduced to what natives of the United States Midwest would call “a rainstorm”.
If you have stayed in Japan over a summer, you have doubtless seen live coverage of a typhoon, usually presented by some hapless reporter standing in the middle of an awful swirl of wind and rain in somewhere like Kumamoto, a small town near the southernmost point of Japan's main islands. While seeing typhoons relentlessly batter Kyushu’s tiny fishing villages, you may be excused in thinking that the worst storm in the world is on its way to you in Tokyo. The truth is that if you sit anywhere north of Osaka, the odds of a typhoon doing any damage to you and your property are quite small. A typhoon relies on warm tropical waters for its strength. Three things help degrade typhoons as they trek up the archipelago: 1) Cooler water in more northern latitudes doesn't give them the energy they need to sustain their power, 2) Making landfall robs them of that energy altogether, and 3) The weakened typhoon often encounters other, stronger weather systems in the middle latitudes, which sap its remaining strength.
Typhoons generally move slower in tropical regions and quicker as it moves north, taking several days to move from Okinawa to Kyushu, but covering the 1,200 km distance from Tokyo to Hokkaido in just 24-36 hours.

While typhoons are predominately a summer phenomenon, you would be mistaken to think they are limited only to the warm months. This past winter, Japan was hit with two major snowstorms in succession on February 7th and February 14th. Both of those storms, which dumped record amounts of snow along the entire breadth of the nation from Fukuoka to Hokkaido, had their genesis in the Philippine Sea, a part of the south Pacific with year around tropical water temperatures, and they were both classified as rare winter typhoons. Winter typhoons are no different than their summer cousins, aside from the fact that they are exceptionally rare. Yet, in early 2014, Japan got two of them in successive weeks, leading to the heaviest snowfalls in over three decades. Is this the new normal? Is global warming to blame? Obviously, two winter typhoons could be looked at as a freak accident and much more data is needed to prove the link conclusively, but the overall warming signs are obvious. Increased water temperature will create more atmospheric uplift, which will provide the necessary energy required to spark typhoons, even outside of their normal summer/autumn patterns.
Japanese naming conventions for typhoons are simple. The Japanese Meteorological Agency goes by numbers. Typhoon No. 1, No. 2, No. 3, etc., and so on. Other areas use more imaginative names, such as Neoguri for the previously mentioned super typhoon. The remainder of 2014 may see typhoons named Matmo, Conson, Talim, Rumbia, and Banyan. As opposed to US Atlantic hurricanes, typhoons (same type of storm, different name) are not named in alphabetical order.
On a Japanese weather map, a typhoon is easy to spot. The singular kanji 台 is used to denote where a typhoon is located. In Japanese, typhoon is pronounced as "tai-fu" (台風).
Typhoons during the summer months do help to clean out the hazy air which tends to accumulate over the Kanto plain, and because of their rotation, they usually bring warmer air from more southerly latitudes in their wake. You may notice a couple of hotter than normal days after a typhoon passes through.
No matter where you are in Japan, the proper response to a typhoon is caution. While it may be downgraded in latitudes above 34 north, do not go around thinking it is completely safe. If you must go out in a typhoon, we wary and stay alert.

by jdlawrence