Monthly Archives: April 2020

Singapore, 30 April 2020 – The warm weather in April 2020 is expected to continue into the first half of May 2020. More showers are also forecast in the next two weeks with the presence of the monsoon rain band over the equatorial Southeast Asia region. During this period, daily maximum temperatures of around 34°C are expected on most days and could reach highs of around 35°C on a few days.

2        The prevailing inter-monsoon conditions are expected to persist into May 2020. In the first half of May 2020, the low-level winds are forecast to be light and variable in direction and may blow from the southeast or southwest on some days.

3        On most days in the first fortnight of May 2020, short-duration thundery showers with frequent lightning are expected between the late morning and afternoon. This is due to strong daytime heating of land areas and convergence of winds over Singapore and the surrounding vicinity. The showers could extend into the evening on one or two of these days. In addition, the presence of low-pressure systems developing over the western Pacific Ocean and the South China Sea are expected to bring a temporary shift in the winds to blow from the southwest or west over Singapore and the surrounding vicinity. This could bring a few days of widespread thundery showers with occasional gusty winds between the predawn and morning, arising from the passage of Sumatra squalls over the island. Overall, the rainfall for Singapore in the first fortnight of May 2020 is forecast to be above-normal over most parts of the island.

4        May is normally one of the warmest months of the year. The first half of May 2020 is forecast to be warm with the daily temperature on most days ranging between 25°C and 34°C. On a few days, the daily maximum temperature could rise to around 35°C. On some nights, warm and humid conditions with night-time temperatures of around 28°C are expected when prevailing winds blowing from the southeast bring warm and humid air from the sea.

5         For updates of the daily weather and haze situation, please visit the MSS website (https://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 – 29 April 2020)

6         The Northeast Monsoon that prevailed over Singapore since December 2019 has ended with the onset of inter-monsoon conditions in end April 2020. The low-level winds in the region weakened in late April 2020 and have become light and variable in direction.

7          April 2020 was wetter compared to the first three months of 2020. On most days in April 2020, thundery showers fell over the island in the afternoon due to strong solar heating of land areas. On 7 April 2020, a Sumatra squall brought widespread heavy showers to many parts of Singapore in the early and predawn hours. The daily total rainfall of 115.0mm recorded at Tuas that day was the highest daily total for April 2020.

8          April 2020 was also warm and humid. At the Changi climate station, the mean monthly temperature for April 2020 of 28.9°C (as of 29 April 2020) was 0.9°C higher than the month’s long-term average. Higher than usual temperatures were experienced over many parts of the island during the month. On most days, the daily maximum temperature reached 34°C, and exceeded 35°C on 15 days. The highest daily maximum temperature of 35.8°C was recorded at Clementi on 10 April 2020.  There were also a few warm nights where the night-time temperature hovered around 28°C, mainly in the southern and eastern parts of the island.

9          About half of the island recorded above-normal rainfall in April 2020. The rainfall recorded at Jurong was 37% above average while that recorded at MacRitchie was 42% below average.

CLIMATE STATION STATISTICS

Long-term Statistics for May
(Climatological reference period: 1981 – 2010)

Historical Extremes for May
(Rainfall since 1869 and temperature since 1929)

Singapore, 15 April 2020 – According to the Meteorological Service Singapore, more thundery showers can be expected over Singapore in the second fortnight of April 2020. This is due to the onset of inter-monsoon conditions and the presence of the monsoon rain band over the equatorial Southeast Asia region during the period. The current warm weather is also expected to continue for the rest of the month.

2          In the second fortnight of April 2020, the low-level winds blowing from the northwest or northeast are forecast to gradually weaken and become light and variable in direction. This signals the cessation of the Northeast Monsoon season and the start of the inter-monsoon period, which is forecast to extend into May 2020.

3          April is typically a month with high lightning activity, and also one of the warmest months of the year. In the early part of the coming fortnight, a brief intrusion of a dry air mass extending from the South China Sea to the equatorial Southeast Asia region is expected to bring dry and warm weather to Singapore. On most days in the fortnight, short-duration thundery showers with frequent lightning are expected between the late morning and afternoon. On one or two of these days, the thundery showers could extend into the evening. The thundery showers are due to strong daytime heating of land areas coupled with convergence of winds over Singapore. Overall, the rainfall for April 2020 is expected to be above-normal over most parts of the island.

4          While more showers are forecast in the coming fortnight, warm conditions can still be expected on some days. The daily temperatures are expected to range between 24°C and 34°C on most days. On a few days during the fortnight, the daily maximum temperature could reach a high of around 35°C.

5         For updates of the daily weather and haze situation, please visit the MSS website (https://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 – 14 April 2020)

6          In the first fortnight of April 2020, weak Northeast Monsoon conditions prevailed and the low-level winds over Singapore and the surrounding region blew from northwest or northeast.

7          Warm weather continued to prevail in the first two weeks of April 2020. During this period, the daily maximum temperature exceeded 34.0°C on most days. On six of these days, the daily maximum temperature was at least 35.0°C, with the highest temperature of 35.8°C recorded at Clementi on 10 April 2020.

8          More rain fell over Singapore in the first fortnight of April 2020 compared to the last fortnight of March 2020. Most of the thundery showers occurred in the afternoon due to strong solar heating of land areas. On 7 April 2020, large-scale wind convergence over the surrounding region triggered a Sumatra squall which brought widespread heavy showers to many parts of Singapore in the early and predawn hours. The daily total rainfall recorded that day was 115mm at Tuas, which is the highest recorded for the first fortnight of April 2020.

9          Most parts of the island recorded above-average rainfall in April 2020. The rainfall recorded at Kranji was 91% above-average while that recorded at MacRitchie was 36% below-average.

CLIMATE STATION STATISTICS

Long-term Statistics for April
(Climatological reference period: 1981 – 2010)

Historical Extremes for April
(Rainfall since 1869 and temperature since 1929)

Singapore, 1 April 2020 – In the first fortnight of April 2020, Singapore and the surrounding region can expect more showers with the proximity of the monsoon rain band close to the Equator. The current warm conditions are forecast to continue in the first two weeks of April 2020 with daily maximum temperatures reaching a high of around 35°C on a few days.

2          Climatologically, April is one of the warmest months of the year, with high lightning activity. During this fortnight, short-duration thundery showers are expected in the afternoon on most days due to strong daytime heating of land areas coupled with convergence of winds over Singapore. On one or two of these days, the thundery showers could extend into the evening. On a few days, a brief intrusion of a dry air mass extending from South China Sea over the region could bring dry and warm weather over Singapore. Overall, rainfall for the first fortnight of April 2020 is expected to be near-normal over most parts of Singapore.

3          While more rain days are expected in the first half of April 2020 compared to the previous fortnight, warm conditions can still be expected on some days. The daily temperatures are expected to range between 25°C and 34°C on most days. The daily maximum temperature could reach a high of around 35°C, in particular on days when there are few clouds in the sky.

4          The prevailing Northeast Monsoon conditions with low-level winds blowing from the northeast or east are expected to persist in the first fortnight of April 2020. Around the end of the fortnight, a gradual weakening of the low-level winds can be expected, signalling the transition to inter-monsoon conditions. The later than usual onset of the inter-monsoon this year, normally by end March, could be attributed to more frequent high-pressure systems over the Western Pacific Ocean which brought persistent easterly winds to the surrounding region.

5         For updates of the daily weather and haze situation, please visit the MSS website (https://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 – 31 March 2020)

6         Northeast Monsoon conditions prevailed in March 2020. During the period, the low-level winds over Singapore and the surrounding region blew mainly from the northwest or northeast. Most of Southeast Asia including Singapore experienced dry and warm conditions in March 2020.

7         In Singapore, it was warm on most days in March 2020. There were 27 days with daily maximum temperatures exceeding 34.0°C, and 10 days when the daily maximum temperature was more than 35.0°C. The month’s highest daily maximum temperature of 36.3°C was recorded at Paya Lebar on 13 March 2020, the highest recorded so far this year.

8          At the Changi climate station, the mean monthly temperature for March 2020 of 28.6°C was 1.1°C higher than the month’s long-term average. The monthly mean minimum temperature for March 2020 was 25.9°C. This was 1.3°C higher than the March long-term average and is the third highest mean minimum temperature recorded for March since 1929, after March 2016 (26.6°C) and March 1998 (26.3°C).

9          During the month, the occasional intrusion of a dry air mass from the southern South China Sea over Singapore and the surrounding vicinity brought little or no rainfall over a two-week period. In the last week of March 2020, it was generally wet over most parts of the island. This was due to the passage of the Madden-Julian Oscillation (MJO)[1] which enhanced the development of thunderstorm clouds over Singapore and the surrounding region. Most of the thundery showers in March 2020 fell in the afternoon due to large-scale wind convergence over the surrounding vicinity. Thundery showers fell over many areas of the island on 23 March 2020. The daily total rainfall recorded that day was 87.8mm at Pulau Ubin, which is the highest recorded for March 2020.

10        Singapore received below normal rainfall in March 2020. The highest anomaly of 67% below average was recorded at Seletar. The lowest anomaly of 14% below average was recorded at Sentosa.

[1] The MJO is characterised by an eastward propagation of clouds and rainfall over the tropical regions from the Indian Ocean to the western Pacific Ocean, with a period of between 30 and 60 days on average. The MJO consists of two phases – an enhanced rainfall (convection) phase and a suppressed rainfall phase.

CLIMATE STATION STATISTICS

Long-term Statistics for April
(Climatological reference period: 1981 – 2010)

Historical Extremes for April
(Rainfall since 1869 and temperature since 1929)