The Weather of November 2011

     As the northeast monsoon affecting southern China was relatively weak, November 2011 was warmer than usual in Hong Kong.  The mean temperature of the month was 23.0 degrees, 1.6 degrees above the normal figure of 21.4 degrees.  The month was also wetter than usual with the monthly total rainfall of 86.1 millimetres, more than double the normal figure of 35.1 millimetres.  However, the accumulated rainfall since 1 January was only 1484.4 millimetres, still a deficit of about 37 percent compared to the normal figure of 2348.2 millimetres for the same period.

     Dominated by a northeasterly airstream, the weather in Hong Kong was generally fine for the first five days of the month.  With the development of a broad area of low pressure over the northern part of the South China Sea and under its combined effect with the fresh to strong northeasterlies, local weather became cloudy and windy with occasional rain from 6 to 10 November.  It was also cooler on 9 and 10 November.  The minimum temperature at the Hong Kong Observatory dropped to 17.7 degrees on 10 November, which was the lowest for the month.  With the weakening of the area of low pressure, local winds moderated gradually and there were still some light rain patches on 11 November.  

     Under the prevalence of a continental airstream, it was mainly fine over the territory from 12 to 16 November.  With a broad cloud band covering the northern part of the South China Sea and the coast of Guangdong, local weather was cloudy with some rain for the next two days.  

     A cold front formed over southern China on 18 November and crossed the south China coast the next day.  During the passage of the cold front, there were a few rain patches on the morning of 19 November.  Under the influence of the northeast monsoon behind the cold front, the weather became slightly cooler with sunny periods on 20 November.  

     Affected by a fresh to strong easterly airstream, it was windy on 21 November.  A cloud band covering the coastal areas of Guangdong brought a few light rain patches to the territory on 22 November.  With a dry northeast monsoon arriving at southern China, local weather turned fine and dry for the next two days.  Affected by another broad cloud band over southern China and the northern part of the South China Sea, it became cloudy with a few rain patches on 25 and 26 November.  As the cloud thinned out, the weather turned fine on 27 November and remained so for the rest of the month.

     There was no tropical cyclone 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 1.2.  Monthly meteorological figures and departures from normal for November are tabulated in Table 2.