Northeast Monsoon conditions to set in towards end Nov’18 and last till Mar’19. Expect the second half of November to be less wet than first, with thundery showers on 5–7 days in afternoon and Sumatra squalls with gusty winds on 3 or 4 mornings.
Singapore, 16 November 2018 – Inter-monsoon conditions with winds that are light and variable in direction have been prevailing over Singapore and the surrounding region since late October 2018. In the second half of November 2018, the inter-monsoon conditions are forecast to persist, and a gradual strengthening and shift in the wind direction to blow from the northeast or northwest are expected towards the end of the month. This change in the monsoonal winds signals the start of the Northeast Monsoon season, and is expected to extend into March 2019.
2 The second half of November 2018 is expected to be less wet than the first half of the month. For the rest of November 2018, localised short-duration moderate to heavy thundery showers are expected mostly in the afternoon on five to seven days, with the showers extending into the evening on a few of these days. These showers are due to the favourable light wind conditions coupled with strong solar heating of the land areas during the day. On three or four days where the winds are forecast to blow from the southwest or west, the passage of Sumatra squalls moving across Singapore from the Strait of Malacca is expected to bring widespread thundery showers accompanied with gusty winds in the morning. Overall, the rainfall for November 2018 is likely to be above normal.
3 In the second half of November 2018, the daily temperature on most days is expected to range between 24°C and 33°C. There could be a few warm days during this period where the daily maximum temperature could reach a high of around 34°C.
4 For updates of the daily weather forecast, please visit our MSS website (www.weather.gov.sg), NEA website (www.nea.gov.sg), or download the myENV app, or the MSS’ Weather@SG app.
REVIEW (1 – 15 November 2018)
5 In the first fortnight of November 2018, inter-monsoon conditions prevailed over Singapore, and the monsoon rain band was located over the equatorial South China Sea region.
6 With winds that were light and variable in direction and ample solar heating of land areas, Singapore experienced moderate to heavy thundery showers in the afternoon on many days. On a few of these days, the thundery showers continued into the night. On 10 and 11 November 2018, flash floods were reported over several parts of the island in the afternoon following a heavy downpour over many parts of the island. On 10 November 2018, the highest daily total rainfall recorded was 103.6 mm at Bukit Panjang. This was exceeded on 11 November when the Holland Road area recorded a daily total rainfall of 104.5mm. The heavy downpour was as a result of localized sea breeze convergence and strong solar heating over land areas during the day.
7 In the first half of November 2018, despite the wet conditions, there were a few warm days where the daily maximum temperature was above 34°C. On most days, the daily maximum temperature ranged between 32°C and 34°C. The highest daily maximum temperature recorded was 34.5°C, recorded on 4 November 2018 at Clementi. The daily minimum temperate on most days ranged between 23°C and 24°C, and the lowest daily minimum temperature recorded in the first half of the month was 22.7°C on 11 November 2018 (at Jurong West and Newton).
8 About three quarters of Singapore received well above average rainfall in the first half of November 2018. The highest rainfall of 309.6 mm (140% above average) was recorded at Bukit Panjang, and the lowest rainfall of 57.2mm (56% below the average) was recorded at Changi.
CLIMATE STATION STATISTICS FOR NOVEMBER (Climatological reference period: 1981 – 2010)
| Mean daily maximum temperature | 31.1 °C |
| Mean daily minimum temperature | 24.3 °C |
| Mean monthly temperature | 27.0 °C |
| Mean rainfall for the month | 258.5 mm |
| Mean number of rain days | 18 |
| Highest monthly mean daily maximum temperature | 32.0 °C (1997) |
| Lowest monthly mean daily minimum temperature | 23.6 °C (1981,1983,1991) |
| Highest monthly rainfall | 508.4 mm (1989) |
| Lowest monthly rainfall | 53.5 mm (1981) |