The rainbands associated with the remnant of Linfa bought shower to Hong Kong this morning, the weather is generally fine. Photo: Dickson Lee
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https://scmp.com/news/hong-kong/health-environment/article/1835654/hong-kong-observatory-defends-hoisting-t8-signal Health & Environment
Hong Kong Observatory defends forecast of Typhoon Linfa
Forecasters say No 8 signal was justified by the data and Linfa weakened faster than expected
Some rain fell on Thursday but Hong Kong avoided the downpours and gusts usually associated with a No.8 typhoon signal. Photo: Sam Tsang
The Hong Kong Observatory yesterday rejected a storm of criticism over Typhoon Linfa, insisting its decision to raise a No.8 signal that triggered a partial city shutdown was for the sake of public safety and based on meteorological data.
Businesses which shut their doors hours earlier than usual were not amused when the force of Linfa proved to be much milder than expected, saying Thursday’s shutdown had caused substantial losses.
Observatory assistant director Dr Cheng Cho-ming explained the inaccurate prediction, saying the storm and its rain bands had contracted rapidly as dry air on land absorbed its moisture.
“It turned out Linfa weakened at a faster pace than we expected. In fact, much faster,” Cheng told Commercial Radio. He said gusts of 63km/h – the minimum wind speed to warrant a No.8 signal – were recorded in Shenzhen.
But most parts of Hong Kong, such as those near sea level, were less windy because the city was shielded by mountainous areas to its north, Cheng said.
On Thursday, the Observatory raised the No.8 signal at 4.40pm, only to downgrade it barely six hours later, with most of the city experiencing no strong winds or heavy rain. Strong winds were recorded over places such as Lau Fau Shan, Chek Lap Kok, Cheung Chau, Ping Chau, Green Island, Tap Mun, Tai Mei Tuk and Sha Chau.
It was only on high ground, such as on Tate’s Cairn and Lantau Island, that occasional gales were recorded.
Federation of Restaurants and Related Trades president Simon Wong Ka-wo estimated the shutdown had cost the catering industry HK$70 million. “Besides doing forecasts on a purely scientific basis, would the Observatory also consider things in a more practical way?” he asked.
An Observatory spokeswoman told said it made decisions purely on the basis of scientific data, instead of taking into account the impact a No.8 signal would have on businesses.
“We understand that probably our warnings have an effect on economic activities, but we do not consider this when it comes to issuing warnings,” she said.
Asked if the Observatory would consider transport needs, she said it would make public announcements two hours before issuing a No.8 signal to give people8 time to get home.
In many cases, including that of Linfa, she said, the Observatory actually made the announcements more than two hours 8before issuing the signal.
Dr Alexis Lau Kai-hon, a scientist at the University of Science and Technology’s centre for coastal and atmospheric research, said Linfa was close and strong enough for the city to issue the No.8 signal. “It is reasonable to raise the alert,” Lau said.
“Even with present modelling, it is not easy to predict sudden8 changes in typhoons.”