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  • The Weather of August 2016

  • 2 September 2016

    The weather of August 2016 was generally rainy with less sunshine than usual. The total duration of sunshine recorded in the month was 148.5 hours, about 21 percent below the normal figure of 188.9 hours. The monthly total rainfall was 532.7 millimetres, about 23 percent above the normal figure of 432.2 millimetres. The accumulated rainfall of 1941.4 millimetres for the first eight months was about 2 percent above the normal figure of 1905.5 millimetres for the same period.

    After skirting past the north coast of Luzon, Nida intensified from a severe tropical storm to a typhoon and headed straight for the coast of Guangdong on the first day of the month. Under the influence of the outer rainbands of Nida, local weather was showery on 1 August with strengthening winds that night. Southerly gales swept in over the territory as Nida made landfall near Dapang Peninsula and moved across Shenzhen just north of Hong Kong on the morning of 2 August. With Nida weakening and moving away, local winds moderated gradually during the day. However, the weather remained overcast with heavy squally showers. More than 100 millimetres of rainfall fell over the territory that day, with rainfall amount even exceeding 200 millimetres in some parts of Lantau Island. The rainy conditions continued over the next couple of days with some heavy showers affecting Lantau Island and Tai Po.

    With an area of high pressure developing over the southeastern part of China, the sun broke through on 5 August, and the weather remained generally fine and very hot over the next three days. As a broad area of low pressure extended from the western North Pacific all the way into the northern part of the South China Sea, the weather over the coastal areas of Guangdong turned more unsettled. Heat showers and intense thunderstorms around noon time on 9 August brought more than 4000 cloud-to-ground lightning stokes to Hong Kong. Cloudy and showery conditions persisted over the next seven days, and even for a rather sunny day on 13 August, there were still some heavy showers affecting the western part of the territory that day. Meanwhile, weak depressions hovered over the south China coastal waters during the period, and from one such depression, Dianmu developed into a tropical storm off the coast of western Guangdong, bringing windy conditions and squally showers to Hong Kong on 17 and 18 August.

    With Dianmu moving away towards northern Vietnam, local weather was a mixture of sunny periods, showers and isolated thunderstorms on 19 - 21 August. The lowest temperature of the month at the Hong Kong Observatory, 24.5 degrees, was recorded in the early hours of 21 August as intense thundery showers swept across the territory. Meanwhile, three tropical cyclones developed in quick succession over the western North Pacific. One of them, Severe Typhoon Lionrock, lingered for days over the sea areas east of the Ryukyu Islands. With southern China under sunny skies and light wind conditions, a spell of fine and very hot weather lasted for six days in Hong Kong from 22 to 27 August. Temperature at the Observatory rose to 34.4 degrees on 25 August, the highest of the month.

    The weather turned cloudier as showery activities affected Hong Kong early on 28 August, and even though the showers eased off, the skies remained cloudy the next day as an intensifying anticyclone over China brought drier continental air to the coastal areas of Guangdong. Despite some sunny periods, mainly cloudy conditions with some showers persisted towards the end of the month.

Landslide at Barker Road during the passage of Nida
Landslide at Barker Road during the passage of Nida
(courtesy of the Geotechnical Engineering Office and the Civil Engineering and Development Department)



Tree blown down near Lei King Wan in Sai Wan Ho during the passage of Nida

Tree blown down near Lei King Wan in Sai Wan Ho during the passage of Nida
(courtesy of Mr Huey Pang)


    Eight tropical cyclones occurred over the South China Sea and the western North Pacific in the month.

    Details of issuance and cancellation of various warnings/signals in the month are summarized in Tables 1.1 to 1.6.  Monthly meteorological figures and departures from normal for August are tabulated in Table 2.
 

Warnings and Signals issued in August 2016

Table 1.1   Tropical Cyclone Warning Signals
Name of
Tropical Cyclone
Signal
Number
Beginning Time Ending Time
Day/Month HKT Day/Month HKT
NIDA 1 31 / 7 2210 1 / 8 1140
3 1 / 8 1140 1 / 8 2040
8 NW 1 / 8 2040 2 / 8 0440
8 SW 2 / 8 0440 2 / 8 1240
3 2 / 8 1240 2 / 8 1710
DIANMU 1 17 / 8 1130 17 / 8 2215
3 17 / 8 2215 18 / 8 1115
1 18 / 8 1115 18 / 8 1315


Table 1.2   Rainstorm Warning Signals
Colour Beginning Time Ending Time
Day/Month HKT Day/Month HKT
Amber 2 / 8 0520 2 / 8 1045
Amber 9 / 8 1230 9 / 8 1330
Amber 10 / 8 0610 10 / 8 0655
Red 10 / 8 0655 10 / 8 0835
Amber 10 / 8 0835 10 / 8 1010
Amber 21 / 8 0220 21 / 8 0410
Amber 28 / 8 0005 28 / 8 0030
Red 28 / 8 0030 28 / 8 0220
Amber 28 / 8 0220 28 / 8 0330


Table 1.3   Landslip Warning
Beginning Time Ending Time
Day/Month HKT Day/Month HKT
2 / 8 0815 2 / 8 1240


Table 1.4   Thunderstorm Warning
Beginning Time Ending Time
Day/Month HKT Day/Month HKT
2 / 8 1515 2 / 8 1615
3 / 8 0330 3 / 8 0530
3 / 8 0805 3 / 8 0915
3 / 8 0930 3 / 8 1600
4 / 8 1155 4 / 8 1800
7 / 8 1200 7 / 8 1400
7 / 8 1530 7 / 8 1730
8 / 8 1515 8 / 8 1815
9 / 8 1100 9 / 8 1530
9 / 8 1930 9 / 8 2015
10 / 8 0445 10 / 8 1230
13 / 8 1145 13 / 8 1445
13 / 8 1615 13 / 8 1800
14 / 8 0135 14 / 8 0315
15 / 8 1525 15 / 8 1930
19 / 8 1930 19 / 8 2130
20 / 8 1320 20 / 8 1730
20 / 8 2005 20 / 8 2115
21 / 8 0110 21 / 8 1200
26 / 8 1835 26 / 8 2045
27 / 8 1530 27 / 8 1600
27 / 8 1755 27 / 8 2030
27 / 8 2255 28 / 8 0400


Table 1.5   Very Hot Weather Warning
Beginning Time Ending Time
Day/Month HKT Day/Month HKT
27 / 7 1145 1 / 8 1800
5 / 8 1215 8 / 8 1945
22 / 8 0745 26 / 8 1815
27 / 8 1100 27 / 8 1715


Table 1.6   Special Announcement on Flooding
in the Northern New Territories
Beginning Time Ending Time
Day/Month HKT Day/Month HKT
2 / 8 0805 2 / 8 1140
10 / 8 0640 10 / 8 0945
28 / 8 0115 28 / 8 0525


Table 2   Figures and Departures from Normal - August 2016
Meteorological Element Figure of the Month Departure from Normal*
Mean Daily Maximum Air Temperature 31.0 degrees C 0.1 degree below normal
Mean Air Temperature 28.4 degrees C 0.2 degree below normal
Mean Daily Minimum Air Temperature 26.5 degrees C 0.1 degree below normal
Mean Dew Point Temperature 25.2 degrees C 0.2 degree above normal
Mean Relative Humidity 84 % 3 % above normal
Mean Cloud Amount 72 % 3 % above normal
Total Rainfall 532.7 mm 100.5 mm above normal
Number of hours of Reduced VisibilityΔ 7 hours 43.6 hours below normal§
Total Bright Sunshine Duration 148.5 hours 40.4 hours below normal
Mean Daily Global Solar Radiation 14.60 Megajoule / square metre 1.03 Megajoule below normal
Total Evaporation 114.6& mm 20.3 mm below normal


  Remarks : All measurements were made at the Hong Kong Observatory except sunshine, solar radiation and evaporation which were recorded at King's Park Meteorological Station and visibility which was observed at the Hong Kong International Airport.

  Δ

The visibility readings at the Hong Kong International Airport are based on hourly observations by professional meteorological observers in 2004 and before, and average readings over the 10-minute period before the clock hour of the visibility meter near the middle of the south runway from 2005 onwards. The change of the data source in 2005 is an improvement of the visibility assessment using instrumented observations following the international trend.
Before 10 October 2007, the number of hours of reduced visibility at the Hong Kong International Airport in 2005 and thereafter displayed in this web page was based on hourly visibility observations by professional meteorological observers. Since 10 October 2007, the data have been revised using the average visibility readings over the 10-minute period before the clock hour, as recorded by the visibility meter near the middle of the south runway.


  *   Departure from 1981 - 2010 climatological normal, except for number of hours of reduced visibility

  §   Departure from mean value between 1997 and 2015

  &   Data incomplete

daily values of selected meteorological elements for HK for August 2016

The percentile map of mean temperature of August 2016

  Remarks : Extremely high: above 95th percentile
Above normal: between 75th and 95th percentile
Normal: between 25th and 75th percentile
Below normal: between 5th and 25th percentile
Extremely low: below 5th percentile
Percentile and 5-day running average values are
computed based on the data from 1981 to 2010