The Weather of November 2019
3 December 2019
With the dominance of dry northeast monsoon over southern China for most of the time in the month, November 2019 was marked by prolonged dry and sunny weather in Hong Kong. The monthly total sunshine duration amounted to 263.0 hours, 46 percent above the normal of 180.1 hours and the fourth highest on record for November. Only traces of rainfall were recorded in the month, making it one of the driest Novembers since records began in 1884. However, the accumulated rainfall this year up to November was 2382.7 millimetres, slightly more than the normal figure of 2371.7 millimetres for the same period. November 2019 was also much warmer than usual. The monthly mean maximum temperature was 26.1 degrees, 2.0 degrees above the normal figure of 24.1 degrees and one of the second highest on record for November. The monthly mean temperature of 23.0 degrees was 1.2 degrees above the normal figure of 21.8 degrees and one of the sixth highest on record for November. Moreover, the autumn mean temperature in Hong Kong for the period from September to November 2019 reached 26.1 degrees and was 1.1 degrees above the normal of 25.0 degrees, making it one of the warmest autumns on record.
Under the prevalence of the dry northeast monsoon, the weather in Hong Kong was fine and dry on 1 – 11 November. With plenty of sunshine, the maximum temperature at the Observatory rose to 29.3 degrees on 1 November, the highest of the month. Following the moderation of the northeast monsoon, it was mainly cloudy with sunny intervals on 12 November. A cold front formed over the northern part of southern China on 13 November and moved across the coastal areas that night. The associated northeast monsoon brought generally fine and slightly cooler weather to Hong Kong on 14 – 17 November.
Meanwhile, another cold front formed over central China edging southwards gradually on 17 November and moved across the south China coast on the night of 18 November. Locally, apart from some haze, the weather in Hong Kong remained fine and dry on 18 November. The northeast monsoon behind the cold front brought cooler mornings to the territory with the minimum temperatures staying below 20 degrees in the next four days. As the northeast monsoon weakened, local temperature recovered gradually on 23 and 24 November.
The strengthening of the northeast monsoon brought windy weather to Hong Kong on 25 November. After a cloudy day on 26 November, the weather turned fine again on the next day. With the replenishment of the northeast monsoon reaching the south China coast on 28 November, it was fine and dry with cool mornings in Hong Kong on 28 – 30 November. The lowest temperature of the month, 17.0 degrees, was recorded on the morning of 29 November.
Six tropical cyclones occurred over the South China Sea and the western North Pacific in November 2019.
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.
Warnings and Signals issued in November 2019
| Beginning Time | Ending Time | ||
|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT |
| 25 / 11 | 1130 | 27 / 11 | 0745 |
| Colour | Beginning Time | Ending Time | ||
|---|---|---|---|---|
| Day/Month | HKT | Day/Month | HKT | |
| Yellow | 3 / 11 | 0600 | 3 / 11 | 1930 |
| Red | 4 / 11 | 0600 | 4 / 11 | 2200 |
| Red | 5 / 11 | 0730 | 5 / 11 | 2145 |
| Red | 7 / 11 | 0600 | 9 / 11 | 1930 |
| Yellow | 10 / 11 | 0600 | 10 / 11 | 1900 |
| Yellow | 17 / 11 | 0600 | 17 / 11 | 1800 |
| Red | 19 / 11 | 0600 | 19 / 11 | 1800 |
| Red | 21 / 11 | 1350 | 21 / 11 | 1945 |
| Red | 22 / 11 | 0645 | 22 / 11 | 1945 |
| Yellow | 24 / 11 | 0600 | 24 / 11 | 1800 |
| Red | 28 / 11 | 0600 | 29 / 11 | 1900 |
| Yellow | 30 / 11 | 0600 | 30 / 11 | 1845 |
| Meteorological Element | Figure of the Month | Departure from Normal* |
|---|---|---|
| Mean Daily Maximum Air Temperature | 26.1 degrees C | 2.0 degrees above normal |
| Mean Air Temperature | 23.0 degrees C | 1.2 degrees above normal |
| Mean Daily Minimum Air Temperature | 21.0 degrees C | 1.2 degrees above normal |
| Mean Dew Point Temperature | 16.8 degrees C | 0.8 degree above normal |
| Mean Relative Humidity | 69 % | 2 % below normal |
| Mean Cloud Amount | 37 % | 17 % below normal |
| Total Rainfall | Trace | 37.6 mm below normal |
| Number of hours of Reduced VisibilityΔ | 19 hours | 102.7 hours below normal§ |
| Total Bright Sunshine Duration | 263.0 hours | 82.9 hours above normal |
| Mean Daily Global Solar Radiation | 16.48 Megajoule / square metre | 4.2 Megajoule above normal |
| Total Evaporation | 106.0 mm | 6.5 mm above 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. |
* Departure from 1981 - 2010 climatological normal, except for number of hours of reduced visibility | |
§ Departure from mean value between 1997 and 2018 | |
Trace means rainfall less than 0.05 mm | |
| 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 |
