Wet 2015 in store for Hong Kong after record number of thunderstorms
Heavier rainstorms could be in store for Hong Kong this year, following a 2014 that saw a record number of thunderstorms strike Hong Kong.
When it rains in 2015, don’t be surprised if it pours.
That’s the advice from the Hong Kong Observatory, which has warned that this year - like 2014 - could see strong rainfall patterns.
The warning comes following the Observatory’s revelation that there were more thunderstorms recorded in 2014 than in any other year since records began in 1947.
A total of 59 days saw storms over Hong Kong, shattering the previous record of 53 days, set in both 1997 and 2013.
Lee Tsz-cheung, a senior scientific officer at the Observatory, said the high number of thunderstorms was caused by frequent low pressure troughs circling southern China, bringing torrential rain.
Troughs are small areas of low atmospheric pressure resulting from columns of rising hot air. As the air rises it cools, forming clouds and precipitation, leading to favourable conditions for thunderstorms.
“There is to some extent a relationship between the frequency of thunderstorms and climatic stability,” Lee said. “Since the trend is that unstable weather is increasing, it is in line with the trend of the increasing number of thundery days.”
Rainfall in Hong Kong in 2014 was 10 per cent up on the 1981-2010 norm used by the Observatory as a benchmark, leading to other broken records in 2014.
On March 30 the Black Rainstorm warning was issued for the first time in March since the warning system was introduced in 1992. Rainfall between 9pm and 10pm that night was the heaviest in a single hour in the month of March since records began in 1884, with 56mm falling on parts of Hong Kong.
Another black rainstorm on May 8 saw “particularly heavy” rain, with 200mm drenching Tai Po, Sha Tau Kok and Sheung Shui, while large hailstones pelted parts of the city
But the wet weather didn’t dull the temperatures. A sizzling summer and autumn saw the highest mean temperature for the June to November period recorded, at 27.6 degrees Celsius, since meteorologists started keeping records in 1884.
And June, July and September also broke records for the hottest individual months, with mean temperatures of 29C, 29.8C and 29C respectively.
The maximum temperature recorded by the Observatory was 34.6 degrees on August 1, while the minimum temperature recorded was 7.3 degrees on February 12.
Lee said the number of rainy days per year had been on the decline over the last century. But he warned the city to brace for more extreme weather. This meant even if it would rain less often, it would likely rain heavily each time.
“As they say, when it rains, it pours," said Lee.
