Hong Kong witnessed a wild mix of weather last month, suffering some of its hottest days ever, two rounds of choking haze, a “red” rainstorm as well as two powerful typhoons.
August 2017 was hotter than normal, the Hong Kong Observatory noted in a press release Monday, adding that “the prolonged heat was relieved by the successive strikes of tropical cyclones Hato and Pakhar within a five-day period during the latter part of the month.”
Both cyclones led to the issuance of No. 8 signals, with Hato even triggering a No. 10 alert — the highest on the Observatory’s storm warning level — on August 23.
The previous time such a top warning signal was hoisted was in July 2012, when Super Typhoon Vicente lashed the city with gale-force winds.
The mean temperature recorded in Hong Kong last month was 29.3 degrees Celsius, the seventh highest for August on record and 0.7 degrees above the August normal of 28.6 degrees, the Observatory noted.
In total seven “Very Hot Weather Warnings” were issued last month.
Due to the rain brought by Hato and in particular Pakhar, the monthly total rainfall amounted to 489.1 millimeters, about 13 percent more than the normal figure of 432.2 millimeters.
Hato and Pakhar
As Hato headed towards Hong Kong, the subsidence effect ahead of its circulation brought smoggy skies and oppressive heat on August 22. The maximum temperature at Observatory that afternoon soared to an all-time record-breaking high of 36.6 degrees. Haze, usually rare in summer, blanketed the city, with air pollution indices, in particular PM 2.5, surging through the roof.
Squally showers associated with the outer rainbands of Hato then started to affect the territory later that day. The weather deteriorated further as stormy weather battered the city during the passage of Hato in the morning on August 23.
Hurricane force winds affected the southeastern part of the territory, and a maximum gust of 193 kilometers per hour was recorded at Waglan Island.
As the approach of Hato coincided with the astronomical high tide, a storm surge induced by Hato resulted in unusually high water levels and serious flooding in many parts of the territory, with Tai O, Heng Fa Chuen, Lei Yue Mun, Sha Tin and Lau Fau Shan among the hardest hit.
Ahead of the visit of the second cyclone Pakhar, oppressively hot and hazy conditions took over Hong Kong once again on August 26, the Observatory said.
Stormy weather persisted for most of the day on August 27 as Pakhar traversed just to the southwest of Hong Kong, resulting in a No. 8 gale warning signal. The temperature at the Observatory fell to the month’s lowest of 24 degrees that day.
Hot conditions with a mixture of sunshine, haze and thundery evening showers then persisted towards the end of the month.
Seven tropical cyclones occurred over the South China Sea and the western North Pacific last month.
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