In what has been a fairly active year so far in the Western Pacific, the latest tropical cyclone to develop has strengthened into a potent system in Micronesia.

The beach at Guam.

The beach at Guam. Image by Luke Ma / CC BY 2.0


Currently located a few hundred miles east-south-east of Guam, Typhoon Dolphin becomes the seventh named storm of the year and could become the third super-typhoon.

Dolphin had its origins as a cluster of heavy showers and thunderstorms last week, several hundred miles south of the Marshall Islands (part of the larger island group of Micronesia).

The showers agglomerated enough to form a circulation in the atmosphere and the Japanese Meteorological Agency (JMA) upgraded it to a tropical depression by May 3. It then continued to strengthen last weekend and through this week while moving west-north-west as it met warm seas and favourable atmospheric conditions.

It will continue to move west-north-westwards during the next 24 hours, with its most likely track moving close to Guam on Friday.

Being the largest island in Micronesia with a population of just over 150,000, contingency plans have been put in place in anticipation of damaging winds and torrential rain.

By the time Dolphin approaches the territory (and nearby island of Rota), sustained winds of 120mph are forecast close to the centre of the storm with higher gusts.

The last typhoon to make landfall on Guam was more than a decade ago, when Pongsona hit in 2002 and wreaked devastation, causing an estimated 900 million US dollars of damage.

Not surprisingly, several flights have been cancelled, schools have been closed and residents have been strongly advised to stay indoors.

Dolphin should have moved through by Saturday, with winds starting to subside, and it is likely to further intensify as it steers north-westwards, potentially attaining super-typhoon status for a time (winds in excess of 130 knots).

However, the good news is that it should remain over open waters when winds reach their peak.

Looking further ahead, it is always difficult to pinpoint where a large system will end up several days ahead since forecast error increases greatly with time.

There does seem to be some agreement though that Dolphin will take a poleward turn later this weekend and, although the system should weaken the further north it travels, a speculative eye is being kept on Japan in case it experiences the remnant strong winds and heavy rain.

(Press Association)