Tag Archive for jma

Japan Meteorological Agency & weather information

Information issued by the Japan Meteorological Agency (JMA) is often unclear and gives a false sense of security. The JMA vocabulary is unique (see image far below). Immediately below are some JMA terms with terms that perhaps better explains what should be intended to be communicated. Much of the vocabulary applies to typhoons, extreme storms, and other natural phenomena. I do not take any responsibility for decisions you make (or fail to make), and the choice of vocabulary is intended to be a guide. It is your responsibility to be well informed both before and during natural disasters and from multiple sources.

JMA vocab::  My interpretation

Warning ::  Extreme danger / high possibility of disaster

Advisory ::  Moderate danger

Tobu      ::  Eastern areas

Seibu     ::  Western areas

JST        ::  Japan Standard Time

UTC       ::  Greenwich Mean Time (I don’t know why they don’t use local times)

Storm    ::   Extremely high danger & extremely strong wind

Gale       ::   Very strong wind with moderate danger

Other information: Generally, the slower the typhoon the more dangerous it is, as it’s dropping more rain and longer in one area. Also, slow moving typhoons tend to have stronger winds. Slow is about 25km/h or less. Strong winds are about 250km/h. Storm surge is where the typhoon draws air and sea water up, creating an artificial high tide. If a storm surge coincides with high tide, then coastal storm surge defences (sea walls) may have waves washing over them. Some sea walls may have been made with sand in them (back in the 1950’s they didn’t know otherwise), so water may pour through some walls, which will result in the sea walls collapsing. Of course, modern sea walls with concrete and asphalt water proofing is usually safer. Typhoons are typically just big wind storms, so the main danger for 90% of people is having heavy things blown onto their heads. In Taiwan, the biggest cause of deaths is from storm wave watchers getting washed away. It goes without saying, get some extra food, water, batteries, beer, and a warm and cuddly friend, and enjoy a bit of indoor time. 😉  Usually, the eastern side of a typhoon has the worst weather spread over a wider area, but the western side will have weaker weather and over a smaller area.

Many train services will still be running, even in the highest level of weather danger. Transport services will only stop running if there has been damage to train lines. Exception is the bullet train (shinkansen) services, which run by more pragmatic rules. Schools, sports carnivals, and companies will still expect workers to arrive at work before or after a typhoon, except when the company’s policy says otherwise. Most companies and schools say that if the JMA state that there is a Storm level (extremely strong wind) warning issued, then don’t come in or go home; but these are dependent on when the warning was issued. Your company or school with have guidelines clearly spelt out, in Japanese, and so you need the phone number of a buddy who can tell you if you have to work today or not.

Information: See the Japan Meteorological Agency website for up to date information, NHK TV, social network sites, and hashtags on Twitter.

Screenshot of JMA website of Typhoon Jelawat information

Screenshot of JMA website of Typhoon Jelawat information