The Weather of November 2006

November 2006 was unseasonably warm. The monthly mean temperature of 23.3 degrees reached an all-time high. The monthly rainfall of 99.6 millimetres was about 184 percent above normal. The accumulated rainfall since 1 January amounted to 2597.9 millimetres, about 19 percent above the normal of 2187.0 millimetres for the same period.

Under the combined effect of the northeast monsoon and Typhoon Cimaron, it was windy and dry on the first two days of the month. Fanned by the dry northerlies, the hill fire which occurred at Tai Lam Country Park on 1 November spread across an area of about 450 hectares and destroyed some 65,000 trees.

With a dry continental airstream prevailing over southern China, the weather remained generally fine and dry from 3 to 12 November. The weather turned cloudy on 13 November when a broad cloud band associated with Tropical Storm Chebi covered the south China coastal areas. It remained mainly cloudy with a few rain patches in the following seven days.

A broad band of rain and thunderstorms affected southern China on 21 November. Locally, the weather was overcast with heavy rain and squally thunderstorms. More than 100 millimetres of rainfall was recorded at Wu Kau Tang and Ma On Shan on that day.

The passage of a weak cold front on 22 November brought slightly cooler weather to Hong Kong. Another cold front moved across the coastal areas of Guangdong on 27 November. The minimum temperature fell to 18.7 degrees at the Observatory on 28 November, the lowest so far this autumn. The weather was mainly cloudy with a few rain patches from 22 to 29 November. Sunny intervals returned when the clouds thinned out on 30 November.

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

Details of issuance and cancellation of various warnings/signals in the month are summarized in Tables 1.1 to 1.4. Monthly meteorological figures and departures from normal for November are tabulated in Table 2.

Warnings and Signals issued in November 2006

Table 1.1 Tropical Cyclone Warning Signals

Name of Tropical Cyclone	Signal Number	Beginning Time		Ending Time
Name of Tropical Cyclone	Signal Number	Day/Month	HKT	Day/Month	HKT
CIMARON	1	31 / 10	1420	3 / 11	1330

Table 1.2 Rainstorm Warning Signals

Colour	Beginning Time		Ending Time
Colour	Day/Month	HKT	Day/Month	HKT
Amber	21 / 11	1530	21 / 11	2025

Table 1.3 Thunderstorm Warning

Beginning Time		Ending Time
Day/Month	HKT	Day/Month	HKT
21 / 11	1345	22 / 11	0600

Table 1.4 Fire Danger Warnings

Colour	Beginning Time		Ending Time
Colour	Day/Month	HKT	Day/Month	HKT
Red	31 / 10	1100	4 / 11	0600
Yellow	4 / 11	0600	6 / 11	0600
Red	6 / 11	0600	8 / 11	0600
Yellow	11 / 11	0600	11 / 11	1145
Red	11 / 11	1145	13 / 11	0115

Table 2 Figures and Departures from Normal - November 2006

Meteorological Element	Figure of the Month	Departure from Normal*
Mean Daily Maximum Air Temperature	25.5 degrees C	1.3 degrees above normal
Mean Air Temperature	23.3 degrees C	1.9 degrees above normal
Mean Daily Minimum Air Temperature	21.6 degrees C	2.4 degrees above normal
Mean Dew Point Temperature	18.5 degrees C	3.3 degrees above normal
Mean Relative Humidity	76 %	7 % above normal
Mean Cloud Amount	65 %	12 % above normal
Total Rainfall	99.6 mm	64.5 mm above normal
Number of hours of Reduced VisibilityΔ	293 hours	154.8 hours above normal§
Total Bright Sunshine Duration	125.6 hours	55.9 hours below normal
Mean Daily Global Solar Radiation	9.99 Megajoule / square metre	3.40 Megajoule below normal
Total Evaporation	78.5 mm	50.6 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.
	The calibration factors of the pyranometer at King's Park in 2006 and 2007 have been re-computed based on the results of a regional instrument comparison in Asia in 2007. The readings of total global solar radiation at King's Park in 2006 and 2007 displayed in this web page before 13 June 2008 have been revised on 13 June 2008 using the new calibration factors.
* Departure from 1961-1990 climatological normal, except for number of hours of reduced visibility.
§ Departure from mean value between 1997 and 2005.

daily values of selected meteorological elements for HK for November 2006

Extract of Meteorological Observations in Hong Kong for November 2006