Significantly below normal rainfall in first half of Dec 2016
Singapore, 16 December 2016 – Northeast Monsoon conditions are forecast to continue to prevail in the last fortnight of 2016. The low level winds during this period are forecast to blow mostly from the northwest or northeast. In addition, short-duration thundery showers, at times heavy, can be expected on seven to nine days, mostly between the late morning and afternoon.
2 On one or two days in the next fortnight, the presence of low pressure systems over the surrounding sea areas are expected to bring a shift in the low level winds to blow from the southwest or west. This could lead to the development of Sumatra squalls over the Strait of Malacca and bring widespread thundery showers accompanied by gusty winds to Singapore between the predawn and morning. The second half of December 2016 is expected to be wetter than the first fortnight of December 2016. Overall, the rainfall for December 2016 is forecast to be below normal.
3 Although December is one of the cooler months of the year, a few warm days can still be expected. In the next fortnight, the daily maximum temperatures on most days are forecast to be around 32°C or 33°C, and on a few days, the daily maximum temperature could reach a high of 34°C. On some rainy days, the daily minimum temperature could range between 22°C and 24°C.
4 For updates of the daily weather and haze forecast, please visit our MSS website (www.weather.gov.sg), NEA website (www.nea.gov.sg), the haze microsite (www.haze.gov.sg) or download the myENV app, MSS’ Weather@SG app.
Review: 1 – 15 December 2016
5 Northeast Monsoon conditions prevailed over the region in the first fortnight of December 2016. While the low level winds blew from the northwest on most days, there were some days when the winds were from the southwest or west due to the influence of Tropical Cyclones “Vardah” and “Nada” over the Bay of Bengal.
6 There were a few warm days in the first two weeks of December 2016 where the daily maximum temperature was between 34°C and 35°C. At the Changi climate station, the mean daily maximum temperature recorded in the first half of December 2016 was 31.8°C, which is 1.6°C above the long-term mean for December. In addition, the mean monthly temperature recorded was 27.8°C, which is 1.4°C warmer than the long-term mean for December.
7 In the first fortnight of December 2016, most of the thundery showers over the island occurred between midnight and 6am. These were due to Sumatra squalls moving across the island, coupled with strong convergence of winds in the surrounding vicinity. In addition, there were a few days of moderate to heavy rainfall over Singapore between the late afternoon and evening due to strong solar heating of land areas. During the period, the heaviest daily rainfall of 45.4mm was recorded on 1 December 2016 around Tuas.
8 For the period from 1 to 15 December 2016, rainfall across Singapore was significantly below normal. The highest rainfall of 128mm (18% below average) was recorded around Changi. Rainfall was lowest around Jurong where 25.2mm (81% below average) was recorded.
CLIMATE STATION STATISTICS FOR DECEMBER (Climatological reference period: 1981 – 2010)
| Mean daily maximum temperature | 30.2 °C |
| Mean daily minimum temperature | 24.0 °C |
| Mean monthly temperature | 26.4 °C |
| Mean rainfall for the month | 318.6 mm |
| Mean number of rain days | 18 |
| Highest monthly mean daily maximum temperature | 31.3 °C (1997, 2002) |
| Lowest monthlymean daily minimum temperature | 23.0 °C (1981,1983) |
| Highest monthly rainfall | 765.9 mm (2006) |
| Lowest monthly rainfall | 62.9 mm (1988) |