Up to seven typhoons will hit Hong Kong this year Observatory says, as it reveals new nine-day forecast

Observatory says weather will be more extreme and unpredictable because of climate change

PUBLISHED : Monday, 17 March, 2014, 6:21pm
UPDATED : Tuesday, 18 March, 2014, 5:22pm

Hong Kong residents should brace themselves for between four and seven typhoons this year, local meteorologists have warned.

The Observatory itself is also girding up for a trying time, because of increasingly unpredictable or extreme weather brought about by climate change.

Freak conditions around the world in recent months - severe flooding in Britain, extreme cold hitting North America and a record-breaking heatwave across Australia - signalled the uphill task ahead, Observatory director Shun Chi-ming said yesterday.

"We can't attribute every extreme weather condition to climate change, but if you piece all of these extreme events together, we can feel that climate change is happening," Shun said. "To some extent, this will make our forecasts more challenging."

The typhoon forecast, made based on sea surface temperatures of the Pacific Ocean, was "normal", he said.

The city's unusually cold snap this winter was because of atmospheric "blocking" - in which regular air streams stagnate, causing temperatures above or below the normal range and other bouts of extreme weather for prolonged periods of time.

Shun said this phenomenon was closely tied to the melting of Arctic ice as a result of rising sea surface temperatures.

"As climate change progresses, more extreme weather will arise," Shun said.

This year, the number of typhoons tipped to come within 500 kilometres of the city - the criterion for determining a typhoon has arrived - will be similar to the seven that hit last year and the five in 2012, which included one signal No10.

There will be less moisture in the region, so annual rainfall is expected to range from 1,700mm to 2,300mm, wavering between normal and below normal.

The rain would be either very light or very heavy, Shun said. "We anticipate a rise in the number of extremely wet years in the 21st century, but the likelihood of drought episodes remains."

Meteorologists believe Hong Kong sea levels will rise 40cm on average by the middle of the century as temperatures increase roughly 2 degrees Celsius.

From next month, the weatherman will implement a nine-day forecast to replace the current seven-day system begun in 2003.

Technology would help the Observatory achieve 80 per cent accuracy, Shun said.