Monthly Archives: November 2018

Northeast Monsoon conditions with prevailing northeast winds have set in over S’pore. In next fortnight, expect 7-9 days of afternoon thundery showers, and 1-2 days to be cloudy and occasionally windy with widespread rain due to monsoon surge.

Singapore, 30 November 2018 – The Northeast Monsoon season has set in over Singapore and the surrounding region, and is expected to prevail till March 2019. During the season, the prevailing winds over the region are expected to blow mainly from the northeast or northwest.

2         For the next two months, the Northeast Monsoon will be in its wet phase where the monsoon rain band typically lies over the equatorial South China Sea. Over Singapore and the surrounding region, it is likely to be wet with more occurrences of short-duration moderate to heavy thundery showers in the afternoon. On some days during the season, a surge of strong northeasterly winds blowing southward over the South China Sea could bring occasionally windy conditions with frequent spells of widespread rain showers over Singapore and the surrounding vicinity. This strengthening of northeasterly winds over the South China Sea, known as a monsoon surge, can last for between two and five days, and also bring cooler temperatures to Singapore. Between two and four monsoon surge events can be expected during the wet phase of the Northeast Monsoon season.

3         The weather in the first fortnight of December 2018 is expected be wet. On seven to nine days in the fortnight, thundery showers occurring mostly in the afternoon can be expected. On a few of these days, the showers could extend into the evening. A monsoon surge is forecast towards the end of the fortnight. This could bring cloudy and occasionally windy conditions with periods of moderate rain, heavy at times, over Singapore and the surrounding region for one or two days. The prevailing winds are also expected to shift to temporarily blow from the west on one to two days during the fortnight. This could bring thundery showers over the island in the morning from a Sumatra squall. For the first half of December 2018, rainfall is forecast to be above normal.

4         In the first half of December 2018, the daily temperature on most days is expected to range between 24°C and 32°C.  There could be a few days during the period where cooler temperatures are expected and the daily minimum temperature recorded could reach a low of between 22°C and 23°C.

5          For updates of the daily weather forecast, please visit our MSS website (https://www.weather.gov.sg), NEA website (www.nea.gov.sg), or download the myENV app, or the MSS’ Weather@SG app.

REVIEW (1 – 29 November 2018)

6         Singapore experienced relatively wet conditions in November 2018. Thundery showers fell over the island on most days of the month.

7         The prevailing winds in November 2018 were mostly light and variable in direction until the end of the month where there was a change in the winds to blow more from the northeast. This change in wind direction in the last week of November 2018 signalled the cessation of the inter-monsoon period and the start of the Northeast Monsoon season.

8       In the first half of November 2018, the light wind conditions coupled with strong solar heating of land areas were conducive for the development of thunderstorm clouds. This brought intense thundery showers in the afternoon over Singapore. In the second half of the month, the prevailing winds blew from the southwest or west for several days, feeding into a low pressure system north of Singapore in the South China Sea. On several days, the thundery showers over Singapore between the early hours and morning were due to Sumatra squalls moving from the Strait of Malacca over the island.

9       The highest daily total rainfall recorded in November 2018 was 110.8mm at Tuas on 21 November 2018. The heavy rainfall that day was caused by an intense Sumatra squall that brought widespread thundery showers accompanied gusty winds over the island. The strongest gust recorded that day was 73.8 km/h at Pasir Panjang. The second highest daily total rainfall of 104.5mm was recorded at Holland Road on 11 November 2018.

10       In November 2018, the daily maximum temperature on most days ranged between 32°C and 34°C. The highest daily maximum temperature recorded was 34.8°C on 28 November 2018 at Clementi. The daily minimum temperature on most days ranged between 23°C and 24°C, and the lowest minimum temperature recorded in the month was 21.4°C on 17 November 2018 at Jurong West.

11       Many parts of Singapore received well above average rainfall in November 2018. The highest rainfall of 433.8 mm (80% above average) was recorded at Jurong, and the lowest rainfall of 162 mm (35% below the average) was recorded at Changi.

CLIMATE STATION STATISTICS FOR DECEMBER (Climatological reference period: 1981 – 2010)

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 (https://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)