Monthly Archives: May 2017

Wet weather expected in second half of May 2017

Singapore, 16 May 2017 – Inter-monsoon conditions characterised by light winds are expected to persist in the next fortnight. Towards the end of the month, the winds are forecast to gradually strengthen and blow from the southeast or southwest as the inter-monsoon conditions gradually transition to Southwest Monsoon conditions around end May/early June 2017.

2          For the second half of May 2017, short-duration thundery showers are expected on six to eight days in the late morning and afternoon, and could extend into the evening on one or two of these days. The thunderstorms can be heavy on some days because of strong convection due to daytime heating of land areas. In addition, widespread thundery showers accompanied by gusty winds due to Sumatra squalls can be expected between the predawn and early morning on two or three days. Overall, the rainfall for May 2017 is forecast to be slightly above normal.

3          For the rest of the month, the daily temperature on most days is expected to range between 24^oC and 33°C. On a few days, the daily maximum temperature could reach a high of 34°C. As the Southwest Monsoon conditions gradually sets in around the end of May/early June 2017, the nights can be relatively warm, in particular on non-rain days. This usually occurs when the weak southeast winds bring warm, humid air from the sea toward the land.

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 May 2017

5          Inter-monsoon conditions prevailed over the region in the first fortnight of May 2017, and the low level winds were generally light and variable in direction. On some days, the prevailing winds blew from the southwest or west due to the influence of low pressure systems in the nearby region.

6          In the first half of the month, there were a few warm days where temperatures above 34°C were recorded. The highest temperature recorded during the period was 34.5°C around the Seletar area on 9 May 2017. At the Changi climate station, the mean daily maximum temperature recorded in the first fortnight of May 2017 was 28.4°C, which is 0.1°C above the long-term mean for May.

7          On most days in the first half of May 2017, the thundery showers in the late morning and early afternoon were due to strong solar heating of land areas coupled with convergence of winds over Singapore and the surrounding vicinity. On a few dayswidespread thundery showers and gusty winds to Singapore between the pre-dawn and the early morning.  The showers were heaviest on 12 May 2017 where the highest daily rainfall total recorded was 84.4mm around Sentosa.

8          Most parts of Singapore received below normal rainfall in the first fortnight of May 2017. The lowest rainfall of 40.4mm (61% below average) was recorded around the Upper Thomson area. Rainfall was highest around Sentosa where 181.4mm (103% above average) was recorded.

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

Thundery showers mostly in the late morning and afternoon

Singapore, 2 May 2017 – The prevailing inter-monsoon conditions where low level winds are generally light and variable in direction are expected to persist in May 2017. Some warm days and thundery showers occurring mostly in the afternoon are common in the month of May due to the strong daytime heating of land areas.

2          In the first fortnight of May 2017, the prevailing winds are forecast to be light and variable in direction on most days. On some days, with the presence of low pressure systems in the nearby region, a temporary shift in the prevailing winds to blow from the southwest or west can be expected. During this period, short-duration thundery showers are forecast mostly in the late morning and afternoon on six or seven days, and could extend into the evening on a few of these days. On two or three days in the first fortnight, widespread thundery showers and gusty winds due to Sumatra squalls can be expected between the predawn and early morning. Overall, the rainfall for the first half of May 2017 is forecast to be slightly above normal.

3          Based on long-term statistics, May is the second warmest month of the year after April. In the first two weeks of May 2017, the daily temperature on most days is expected to range between 25°C and 34°C. Warm temperatures of between 34°C and 35°C are expected on some days when there is strong solar heating and the winds are light.

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 – 30 April 2017

5          Inter-monsoon conditions prevailed in the region in April 2017, with low level winds that were predominantly light and variable in direction.

6          During the month, Singapore experienced thundery showers mostly in the afternoon due to strong daytime heating of land areas coupled with convergence of winds in the surrounding vicinity. The occurrence of Sumatra squalls on several days in April 2017 brought widespread thundery showers and gusty winds over Singapore between the pre-dawn hours and the early morning. The heaviest rainfall recorded for April 2017 was from a Sumatra squall that brought 102mm of rain in a day. This occurred over the Tuas area on the morning of 21 April 2017.

7          At the Changi climate station in April 2017, it rained on 22 days[1] and the mean temperature recorded was 27.8°C. This is two days more and 0.2°C cooler than the long-term record number of rain days and mean temperature respectively for April. There were several warm days in April 2017 where the daily maximum temperature on these days ranged from 34.1°C to a high of 35.2°C.

8          Most parts of Singapore received above normal rainfall in April 2017. The highest rainfall of 358.4mm (55% above average) was recorded around the Paya Lebar area. Rainfall was lowest around Seletar where 205.2mm (11% below average) was recorded.

[1] A day is considered to have ‘rained’ if the total rainfall for that day is 0.2mm or more.

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