Fortnightly Weather Outlook for 16 – 30 April 2021
Singapore, 16 April 2021 – The prevailing inter-monsoon conditions over Singapore and the surrounding region are expected to persist through May 2021. In the coming fortnight, more showers are forecast over Singapore and the surrounding vicinity, and the low-level winds are forecast to blow from the southwest or west. In the later part of the fortnight, the winds are expected to weaken to become light and variable in direction.
2 In the early part of the coming fortnight, a low-pressure system is forecast to develop over the western Pacific Ocean. This is expected to bring large scale convergence of winds blowing from the west and southwest over the equatorial Southeast Asia region. On most days during this period, Sumatra squalls are forecast to develop over the Strait of Malacca and move eastwards to bring widespread thundery showers and gusty winds over Singapore between the predawn hours and morning.
3 In the later part of the fortnight, the winds are forecast to become light and variable in direction. On most days during this period, short-duration moderate to heavy thundery showers with frequent lightning are expected in the afternoon over parts of the island. Overall, the rainfall in April 2021 is forecast to be above average over most parts of the island.
4 During the fortnight, the daily maximum temperatures on most days are expected to range between 33°C and 34°C. On a few rainy days, the daily minimum temperature could reach a low of around 22°C.
REVIEW (1 – 15 April 2021)
6 Northeast Monsoon conditions transitioned to inter-monsoon conditions in early April 2021. The low-level winds blew from the northeast or northwest before becoming light and variable in direction around the end of the first week of the month.
7 In the first two weeks of April 2021, thundery showers fell over parts of the island in the afternoon on most days due to strong solar heating of land areas. On a few days, the showers continued into the evening due to large-scale convergence of winds in the surrounding region. The highest daily total rainfall recorded in the first fortnight of April 2021 was 96.0mm at Jurong on 3 April 2021.
8 Although it rained on most days during the first half of the month, there were 12 days during the period when the daily maximum temperature was more than 34°C. The highest daily maximum temperature during the first fortnight of April 2021 was 36.3°C recorded at Ang Mo Kio on 2 April 2021.
9 Many parts of Singapore recorded above-average rainfall in the first fortnight of April 2021. The rainfall recorded at Changi was 104% above-average while that recorded at Kranji was 23% below-average.
CLIMATE STATION STATISTICS
Long-term Statistics for April
(Climatological reference period: 1981 – 2010)
|Average daily maximum temperature||32.3 °C|
|Average daily minimum temperature||25.0 °C|
|Average monthly temperature||28.0 °C|
|Average rainfall||154.8 mm|
|Average number of rain days||14|
Historical Extremes for April
(Rainfall since 1869 and temperature since 1929)
|Highest monthly mean daily maximum temperature:||33.9 °C (1983)|
|Lowest monthly mean daily minimum temperature:||23.1 °C (1934)|
|Highest monthly rainfall ever recorded:||454.9 mm (1900)|
|Lowest monthly rainfall ever recorded:||16.6 mm (1977)|