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Avoiding Tropical Cyclone Mayhem

December 18, 2017

Yearly, confusion prevails during Autumn when tropical cyclones move from the Philippine Sea towards China or Japan. Last October, Typhoon Chaba wreaked havoc through the Asian waters.

The following bulletin was issued by the Japanese Meteorological Agency, which has WMO responsibility for the area:

NAME TY 1014 CHABA (1014)
PSTN 280000UTC 24.3N 128.6E GOOD
50KT 70NM
30KT 220NM

Philippine Sea The bulletin calls for 30 knot winds extending for 220 NM from the center, while the above image shows 30 knot winds extending from Shanghai to Luzon, and from the China coast some 800NM to the east. Can the official bulletin be completely wrong? The answer is no, but it is important to understand that the radius described is for those winds circulating around the storm. However, the gradient of the pressure between high pressure over Asia and a distant storm can cause high winds over an extremely large area, and ship operators should be aware of the effects such conditions have on the ability of a ship to make her speed and schedule.

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The tropical season for 2011 is well underway, with active tropical cyclones in the Atlantic, as well as in the Eastern and Western Pacific. In the September 2010 Shipping Insights Newsletter article, we described a "what-if" factor in relation to a hurricane in the Atlantic. In this article, we discuss the benefits for typhoon avoidance in the Pacific.

Because tropical cyclones are noted for severe wind/seas in a relatively small area, tactical navigation decisions become critical. These decisions must be made in a timely manner to gain the most benefit for the vessel as well as the shipping client.

Southern Japan During the recent Typhoon Ma-On which occurred in July 2011, StormGeo staff made numerous recommendations, and relayed them to many vessels which were approaching or departing Japanese ports. Once a typhoon starts re-curvature, mariners will often try to avoid the northeast quadrant in order to avoid being in the path of the storm as it accelerates northeastward. However, the typhoon approached Southern Japan and curved eastward in response to high-pressure to the north instead of taking a more northeasterly track as would typically be expected from a re-curving typhoon.

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The following is an example of how StormGeo provided advice to a vessel approaching Japan from the East.

Philippine Sea The image above shows the StormGeo suggested route in RED with a typical alternate track (LIGHT RED) that a Master might select without guidance. StormGeo suggested that the captain sail west, maintaining enough latitude to clear safely north and west of the heavier adverse conditions associated with Typhoon Ma-On. The Master was very cooperative and followed the guidance of StormGeo.

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A comparison was done between the actual voyage with a hypothetical alternate route. It revealed that the sailing time difference was reduced by about 24 hours when choosing StormGeo’s route guidance. The vessel in this example normally consumed 34 tons of fuel per day. At a hire rate of $15,000 USD per day and fuel costs of about $685 USD per ton, the savings were calculated to be $38,000 USD.

Additionally, about 100 metric tons (MT) of greenhouse gasses (GHG) were saved with this one tactical tropical advisory.

This is a small example of how StormGeo ship routing saves clients operating costs and reduces greenhouse gases while providing safe passage to the crew, cargo and vessels.