Photo 25th (Monday) 9:20 am Typhoon No. XNUMX position and course forecast
Typhoon No. 20 occurs and moves north while developing. Approaching Ogasawara in the latter half of the week
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Typhoon No. 25 occurred in the east of the Philippines at 9 am on the 20th.The central pressure of the typhoon is 1002 hectopascals, the maximum ... → Continue reading
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Typhoon information(Typhoon) isJapanese Meteorological AgencyTo announceDisaster prevention weather informationone of.typhoonCurrent position and path, strength, center(I.e.And so on.It often refers to typhoon information reported on TV and radio based on this information.There are three types of information to be released: typhoon route map, probability of entering a storm area, and general typhoon information.
- 1945 By usaAirplane observationIs started.
- 1950 May 7 Classification and definition of "tropical cyclone" and "typhoon" are decided.
- Maximum wind speed of 34 knots (17.2 m / s) or less "Weak tropical low pressure", 35 to 64 knots (18 to 32.7 m / s) "Tropical low pressure", 65 knots (33.4 m / s) or more "Typhoon" ..
- 1952 May 6 Typhoon forecasting work begins.The typhoon track forecast is displayed as a dot, and an error range is added to it.
- May 6 The name of the typhoon will be the number from the American female name to the order of occurrence.
- Started summer course forecast.The forecast time is 12 hours and 24 hours ahead in a fan shape.
- 1961 May 6 The operation of Nagoya radar is started.
- 1962 May 10 Determine the classification of typhoon size and strength.
- Size: Wind speed of 15m / s or more and less than 200km radius "Very small", 200-300km "Small (small)", 300-500km "Medium size (medium size)", 500-800km "Large (large)", 800km or more "super large (very large)"
- 強さ：最大風速33ノット以下（17.2m/s未満） 「弱い熱帯性低気圧」、34〜47ノット（17.2〜24.5m/s） 「弱い」、48〜63ノット（24.6〜32.6m/s） 「並の強さ」、64〜84ノット（32.7〜43.7m/s） 「強い」、85〜104ノット（43.7〜54.0m/s） 「非常に強い」、105ノット以上（54.0m/s超） 「猛烈な」。
- 1964 May 11 Mount Fuji radarThe operation of is started.
- 1975 The names of "storm zone" and "strong wind zone" have been changed to "storm zone" and "strong wind zone", respectively.
- 1978 May 4 Meteorological satellite-sunflowerThe operation of is started.
- 1979 From the English name of the typhoon, No. 2, it is decided to alternately name men and women from only female names.The first application was No. 4 CECIL that occurred in April.
- 1982 As of June 6stForecast circleThe course forecast of the method is started.Before that, he used to forecast the course of a fan shape.
- 1986 June 6 Storm alert area is added.It became the prototype of the current typhoon track forecast map.
- 1989 July 7st, the course forecast for 1 hours ahead will start.
- 1992 May 4 We will start announcing the probability of entering a storm area within 29 hours at 24 points nationwide.
- The course forecast up to 72 hours ahead will start.
- Change the probability of entering the forecast circle from 60% to 70%.
- May 1 The name of the typhoon will be changed to that submitted by Asian countries and the United States.
- Delete "medium size", "small size", "very small", "normal strength", and "weak" in the size and strength of the typhoon.
- Changed the name of "weak tropical cyclone" to "tropical cyclone".
- Size: Wind speed of 15m / s or more and radius of less than 500km None, 500-800km "Large (large)", 800km or more "Super large (very large)"
- 強さ：最大風速33ノット以下（17.2m/s未満） 「熱帯性低気圧」、34〜63ノット（17.2〜32.6m/s） 特になし、64〜84ノット（32.7〜43.7m/s） 「強い」、85〜104ノット（43.7〜54.0m/s） 「非常に強い」、105ノット以上（54.0m/s超） 「猛烈な」。
- 2001 June 6 Intensity forecast up to 1 hours ahead will begin.
- Intensity forecast up to 72 hours ahead will start.
- The probability of entering a storm area will be expanded to forecasts up to 3 hours ahead every 48 hours for each warning and warning announcement category.
- Announce the estimated position one hour later.Prior to that, only the outline place names were announced.
- 2004 June 6 The forecast circle will be reduced due to improved typhoon track forecast results.
- 2007 May 4 Significantly expand typhoon information.A course forecast every 3 hours, information on the maximum instantaneous wind speed, and a distribution map of the probability of entering a storm area will be added near Japan.
- 2008 May 5 The forecast circle will be reduced by improving the results of the typhoon track forecast.
- 2009 May 4 Typhoon 5-day forecast starts.
- 2019 May 3 Intensity forecast up to 120 hours ahead begins.
- 2019 May 6 Approximately 20% smaller forecast circle than before due to improved typhoon track forecast results.
Typhoon track forecast map
Based on the information released by the Japan Meteorological Agency, it will be displayed on the map on TV and websites such as the Japan Meteorological Agency website.
The contents of the information released by the Japan Meteorological Agency are as follows.
Forecast up to 72 hours ahead
- Typhoon number -(Last two digits of the Christian era) XX year XX.The Japan Meteorological Agency reads "(year) XX year XX" in general typhoon information.In the private sector, it is often called "typhoon XX" by omitting "first" and year.
- Central position of typhoon --- Latitude and longitude are in 0.1 ° units.In general typhoon information, it is replaced by minutes.There are three levels of analysis accuracy at the center position of the typhoon, and there are three types: "accurate" (about 3 km or less), "almost accurate" (60 to 60 km), and "inaccurate" (about 110 km or more).
- Typhoon size and strength --Divided by the size of the strong wind region and the maximum wind speed.Do not use if the strong wind area is less than 500 km and the maximum wind speed is less than 33 m.
- Location of typhoons --Mainly the name of the sea area.If it is close to land, it will be the distance from the city.
- Direction and speed of travel --There are 16 directions.The speed is km / h and knots are used. At speeds less than 10km / h, the notation is "slow".The direction of travel is not used when it is almost stagnant.
- Central pressure --Unless it is close to the observatory, it is not an observed value but an analysis value by the Dvorak method.
- Maximum wind speed --Maximum average wind speed for 10 minutes. Two types of units are used: m / s and knots.Normally, it is the "maximum wind speed near the center", but depending on the structure of the typhoon, "near the center" may be removed.
- Maximum instantaneous wind speed --Elements newly added from April 2007, 4. Two types of units are used: m / s and knots.It is more intuitive information because the maximum instantaneous wind speed is often used rather than the maximum wind speed in news reports such as television.
- Storm area ――The area where a storm with a wind speed of 25 m / s or more may blow is indicated by a circle.
- Strong wind ――The area where a strong wind with a wind speed of 15 m / s or more may blow is indicated by a circle.In storm areas and strong wind areas, the effects of ground friction and terrain are not taken into consideration.Even if the wind is weak even though it is in a storm area, the wind may suddenly increase due to changes in the wind direction due to the movement of the typhoon, so be careful.
- Forecast circle --The range in which the center of the typhoon advances at an arbitrary forecast time is indicated by a circle.Currently, the probability of entering the forecast circle is 70%. After 12,24 hours, it will be announced every 3 hours, and after 48,72 hours, it will be announced at 3, 9, 15, and 21:12. Forecasts after 2007 hours may be omitted. From April 4, 18, a new forecast circle will be added 3,6,9,15,18,21 hours after approaching Japan and typhoons.In addition, a line connecting the centers of the forecast circles is displayed on the typhoon track forecast map.
- Storm alert area --The range that may enter the storm area when the center of the typhoon advances within the forecast circle.The longer the forecast period, the larger the storm warning area, but the storm area does not necessarily increase.From April 2007, 4, the typhoon track forecast map will change from the conventional circle to a line surrounding the storm warning area during the forecast period.
- Estimated position after 1 hour ――Since there is a gap of about one hour between the current state of the typhoon and the announcement of information, the same information as the current state will be announced in the typhoon approaching Japan.
Forecast up to 5 days ahead
- Announced when it is predicted that a typhoon will exist up to 3 days ahead.However, it may be omitted if there is a high possibility that the typhoon will disappear due to landing of a typhoon or movement outside the target area.
- The forecast will be announced four times a day with analysis at 3, 9, 15, and 21:1.
- The probability of entering the forecast circle is 72%, which is the same as up to 70 hours ahead.
Probability of entering a storm zone
Forecast by region
- From April 1992, 4, we started to announce the probability of entering the storm zone.At that time, the forecast was for up to 1 hours ahead, targeting 29 major points nationwide.
- The content of the announcement has been improved from June 2003, 6, and has been expanded since April 4, 2007.
- The probability of entering a typhoon storm area will be announced in units of nationwide warning and warning announcement areas and all 374 areas targeting the Ogasawara Islands.
- This information is useful for grasping the time to enter and exit the storm area, but the probability changes greatly due to the change in the forecast, and the error range (forecast circle) of the forecast increases as the time goes ahead. Therefore, it should be noted that there is no large probability.
Probability distribution map
From April 2007, 4, we started to publish the distribution map of the probability of entering the typhoon storm area.
- The target area will be announced in the area of latitude 20 to 50 degrees north and longitude 120 to 150 degrees east.
- It may be replaced with a storm warning zone and displayed overlaid with the forecast circle.
General typhoon information
Various information about typhoons will be announced in text.The information to be announced is roughly divided into two types: location information and general information.
It is announced in typhoons that are expected to approach Japan, usually every 3 hours, and typhoons that are expected to approach or land considerably are announced every hour.Information will also be released in tropical cyclones that are expected to develop into typhoons within 1 hours near Japan, and even if a typhoon changes to an extratropical cyclone, typhoon information will continue if it is accompanied by a storm.
- The location of the center of the typhoon (with the area name)Latitude）
- Typhoon forces (central pressure, maximum wind speed)
- Direction of travel and speed of movement
- Storm and strong winds
- Estimated position after 1 hour
- Career forecast (every 24 hours until 3 hours ahead, up to 3 hours ahead at 9, 15, 21 and 72:XNUMX)
This information is often used when the press says "according to the observations of the Japan Meteorological Agency".If the estimated position is used, it will be "according to the announcement by the Japan Meteorological Agency".
Appendix (location details)
If the Japan Meteorological Agency announces a course forecast every three hours, detailed location information will be announced as an appendix to the location information.Use the same typhoon information numbers.The contents are as follows.
- The actual condition and the estimated position after 1 hour
- Approximate position, size class, strength class, center position, movement, central pressure, maximum wind speed, maximum instantaneous wind speed, storm area, strong wind area
- Approximate position (excluding forecasts after 3, 6, 9, 15, 18, 21 hours), strength class, forecast circle center and radius, movement, central pressure (if it changes to an extratropical cyclone or tropical cyclone) Addition), maximum wind speed, maximum instantaneous wind speed, storm warning zone
Information related to disaster prevention such as typhoon outlook and expected rainfall, and points to note regarding disasters will be announced.In addition, information on the occurrence and landing of typhoons will be announced.The greater the impact on Japan, the shorter the presentation interval.
- Typhoon landing
- Quantitative forecast (expected rainfall, expected maximum wind speed, waves, storm surge, etc.)
- Precautions for disaster prevention
As for information on a local or prefectural basis, detailed typhoon information will be announced in the local meteorological information and prefectural meteorological information.In the Kyushu region, there are cases where "heavy rain, (lightning strike,) gusts (storms and high waves) are announced as" weather information ", and only Nagasaki Prefecture is announced as" typhoon-related weather information ".
- ^ "Improvement of typhoon information by Japan Meteorological Agency”. Japan Meteorological Agency. NovemberBrowse.
- ^ "About extension of typhoon intensity forecast to 5 days ahead”. Japan Meteorological Agency (April 2019, 2). NovemberBrowse.
- ^ "About improvement of typhoon course forecast". www.jma.go.jpJapan Meteorological Agency. NovemberBrowse.
- Japanese Meteorological Agency