Taiwan could be hit by two to four typhoons this year, the Central Weather Bureau (CWB) said yesterday.
Cheng Ming-dean (鄭明典), director of the bureau’s weather forecast center, said that high air pressure in the Pacific Ocean looks set to be weaker than normal this summer, while the low air pressure in the South China Sea is showing a tendency to be strong. These two systems are crucial indicators on the formation and movement of typhoons, he said.
“Research has shown that typhoons are likely to be more active in maritime areas off the nation’s east coast when there is high air pressure weakness in the Pacific Ocean,” Cheng said. “The chances of tropical disturbances, which are generally the precursors of tropical storms, increase if low air pressure is strong in the South China Sea.”
Cheng said the formation of typhoons is also affected by the El Nino or La Nina effect, adding that all the indicators have shown that weather patterns in the second half of this year would fall within the normal range.
The bureau said 23 to 27 typhoons will be formed in the western Pacific Ocean this year, with two to four of them directly affecting Taiwan.
On average, 25.7 typhoons are formed in the western Pacific each year, with 3.6 of these hitting Taiwan directly, Cheng said.
The bureau said five typhoons have formed in the northwest Pacific so far this year, slightly more than usual.
Though most typhoons that form in the western Pacific do not hit Taiwan, they could still cause damage by inducing the southwest monsoon and bringing heavy rain to central and southern regions, Cheng said.
The best example was the devastation caused by Typhoon Morakot in 2009.
Northern and northeastern regions of the island would also see damage if the typhoons occur in the fall, with the combined effect of typhoons and the northeast monsoons bringing strong rainfall to these two regions. Generally, the typhoon season lasts from July to September.
The bureau also forecast that summer temperatures are likely to be normal or slightly higher than average, with rainfall this month also slightly higher than normal. Cheng said that summer seems to have arrived earlier than usual this year.
The temperature in Taipei reached 36.7°C at 10:48am yesterday, the highest temperature recorded so far this year in the capital, breaking the previous record of 36.6°C set on Friday last week.
The highest temperature yesterday was recorded in Dawu (大武) in Taitung County, where the mercury hit 37.4°C. The previous record of 37.3°C was set on June 8.
Between June 1 and Tuesday, the average temperatures recorded in 15 of 24 observation stations have made this month among the 10 hottest Junes on record.
Cheng said the average temperature in the plum rain season, which lasts from May to this month, has been higher than normal this year. Cheg said that although rainfall in the plum rain season was within normal range, most occurred last month, adding that this month has been relatively drier.