Tuesday, July 8, 2014

Tracking Typhoons

From Hurricane Arthur to Typhoon Neoguri

It may not be as smooth as the National Hurricane Center but you can still track Typhoon Neoguri. The track looks similar and aside from a few added geometric shapes, is the exact same track you would find coming from the NHC.
  • Track Line
  • Center Position Forecast
  • Position estimate circle drawm at each time

Neoguri Track
Japan Meteorological Agency Neoguri Track


 Cone of Uncertainty

The forecast issued by any agency is a position estimate for the center of the storm at a given time interval. The storm center at that time has a 67% (70% with the Japan Forecast) of falling within the circle. A line is drawn connecting all the circles and you end up with a forecast cone.

NHC Arthur Cone of Uncertainty
National Hurricane Center Arthur Track
  • Forecast Cone Width Depends on Forecast Uncertainty
  • Cone Appears to Grow Over Time Due to Greater Uncertainty
  • Center of the Storm can Track Anywhere in the Cone


Ignore the Forecast Track Line

The NHC does not draw the center line on the forecast track page to avoid misleading the public into a false sense of security should they see the line not crossing their area. The forecast from Arther is a perfect example Above. The center track line would have remained off the coast but the western edge of the cone covered the actual track of the storm. As stated by the Hurricane Center it is important to remember that hazardous conditions could exist outside the cone since it is only represents the center of the storm and not the size.


The Joint Typhoon Warning Center (JTWC) is a task force that covers the Pacific and the Indian Ocean. The forecast graphic is not a position probability estimate but a single track with the circles representing the wind speed field.

Joint Typhoon Warning Center Neoguri Track


Japan Meteorological Agency

Navigating this page is a little tricky and there are a number of menu options but the track issued is very similar to the National Hurricane Center in the US. The only difference is the probability circles remain on the map which can make it look very geometric. If you look at the center line (then ignore it as stated) you can see each circle with the cone drawn along the outside.

Japan Meteorological Agency Neoguri Track
Japan Meteorological Agency Neoguri Track

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