Fortnightly Weather Outlook for 16 – 30 November 2019
Singapore, 15 November 2019 – In the second half of November 2019, the prevailing inter-monsoon conditions are expected to transition to the Northeast Monsoon. During this period, the prevailing low-level winds that are light and variable in direction are forecast to gradually strengthen and blow from the northeast or northwest. The Northeast Monsoon season, which is also the rainy season over southern Southeast Asia, is expected to extend into March 2020.
2 During the Northeast Monsoon season, the low-level winds originating from East Asia gather moisture as they pass over the South China Sea and converge over the equatorial Southeast Asia region. This enhances the development of the monsoon rain band lying over the region, and brings more showers to Singapore and the surrounding region. As a result, coupled with strong solar heating of land areas during the day, Singapore can expect short-duration thundery showers in the afternoon on seven to nine days in the second half of November 2019.
3 Around the end of the month, a further strengthening of the northeasterly winds over the equatorial South China Sea is expected. This is likely to bring cloudy conditions and moderate to heavy thundery showers over Singapore between the late morning and evening on one or two days. Overall, the rainfall for November 2019 is likely to be near-normal for most parts of Singapore.
4 With more rain days forecast in the last two weeks of November 2019, it is expected to be slightly cooler compared to the warm days experienced over the past weeks. The daily temperature on most days is forecast to range between 24°C and 33°C. There could still be one or two warm days where the daily maximum temperature could reach a high of around 34°C. On a few nights, the daily minimum temperature could reach a low of around 23°C.
5 For the rest of November 2019, the gradual strengthening of the northeasterly winds over the equatorial Southeast Asia region is expected to alleviate any occasional slight haziness due to the accumulation of particulate matter in the atmosphere under light wind conditions.
6 For updates of the daily weather and haze situation, please visit the MSS website (www.weather.gov.sg), NEA website (www.nea.gov.sg), or download the myENV app, MSS’ Weather@SG app, and the haze microsite (www.haze.gov.sg).
REVIEW (1 – 15 November 2019)
7 In the first fortnight of November 2019, Singapore and the surrounding region experienced inter-monsoon conditions with low-level winds that were generally light and variable in direction.
8 In the fortnight, short-duration thundery showers fell over parts of the island between the late morning and afternoon on all but two days during the period. Compared to the last fortnight of October 2019, the showers in the first fortnight of November 2019 were less widespread and less intense. This was due to the slight northward shift of the monsoon rain band away from the Equator because of the development of low-pressure systems in the northern South China Sea and Pacific Ocean. On 5 November 2019, thundery showers fell over many parts of the island in the late morning and early afternoon due to convergence of winds feeding into rain bands extending from Typhoon Nakri in the South China Sea. The highest daily total rainfall recorded that day was 47.4mm over the southern part of the island at Kent Ridge.
9 Singapore recorded slightly warmer temperatures in the first fortnight of November 2019 compared to the last fortnight of October 2019. The daily maximum temperatures reached above 34°C for more than half of the fortnight, and the highest daily maximum temperature recorded was 34.9°C on 7 November 2019 at Marina Barrage and Ang Mo Kio.
10 On a few days toward the end of the fortnight, Singapore experienced slight haziness with the 24-hr PSI ranging between the high end of the Moderate and the low end of the Unhealthy range. The slight haziness was due to the accumulation of particulate matter in the atmosphere under light wind conditions. While some showers on 12 and 13 November 2019 helped to improve the air quality over the island, the light winds slowed the dispersion of the particles and the haziness lingered over the two days. The air quality improved to the Moderate range on 14 November 2019. This was due to the occurrence of showers over the island and surrounding vicinity and a strengthening and shift of winds to blow from the northeast over Singapore from the early hours of 14 November 2019.
11 In the first half of November 2019, most parts of Singapore recorded below-average rainfall. Sentosa recorded the highest rainfall anomaly of 96% below average while Ang Mo Kio recorded the highest rainfall anomaly of 14% above average.
CLIMATE STATION STATISTICS
Long-term Statistics for November
(Climatological reference period: 1981 – 2010)
|Average daily maximum temperature||31.1 °C|
|Average daily minimum temperature||24.3 °C|
|Average monthly temperature||27.0 °C|
|Average rainfall||258.5 mm|
|Average number of rain days||18|
Historical Extremes for November
(Rainfall since 1869 and temperature since 1929)
|Highest monthly mean daily maximum temperature:||32.1 °C (2015)|
|Lowest monthly mean daily minimum temperature:||22.4 °C (1933)|
|Highest monthly rainfall ever recorded:||521.5 mm (1874)|
|Lowest monthly rainfall ever recorded:||53.5 mm (1981)|