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RSMC Tokyo-Typhoon Center

Technical Review No.8  (March 2005)

  Reduction of the Radius of Probabilitiy Circle in Typhoon Track Forecast
  Nobutaka MANNOJI
  National Typhoon Center, Japan Meteorological Agency

 RSMC Tokyo - Typhoon Center of the Japan Meteorological Agency (JMA) presents tropical cyclone track forecasts with probability circles* to indicate uncertainty of the forecasts. Based on the verifications of the forecasts issued from 2001 to 2003, the Typhoon Center reduced the radii of probability circles by 10% on average on 1 June 2004.
  * A circular range in which a tropical cyclone is located with a probability of 70% at each forecast time.
   Text [PDF 0.2MB]

  Verification of the Guidance during the Period of Typhoon Songda (0418)
  Youichi KIMURA, Kazuzo NIIMI
  Numerical Prediction Division, Japan Meteorological Agency

 As one of the operational meteorological analysis and forecast products, guidance for maximum sustained wind speed (hereinafter reffered to as "maximum wind speed") and maximum precipitation has been used to assist forecasters of the Japan Meteorological Agency (JMA) in issuing weather forecasts, warning and advisories. In this report, practical effectiveness of the guidance for the extreme event was verified, taking an example of the case of Typhoon Songda (0418) which caused considerable damamge in Japan. The verification revealed that those guidances were reliable products in a paractical level even in this extreme event.
   Text [PDF 0.2MB]

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