Onset of Inter-Monsoon Conditions By End-October 2016

Expect some warm days in the next fortnight

Singapore, 17 October 2016 – The prevailing Southwest Monsoon is expected to weaken toward the end of October 2016 as the region enters the Inter-Monsoon period. During the coming two weeks, the low level winds are forecast to blow from the southwest before becoming light and variable in direction towards end of the month. Inter-Monsoon conditions are characterised by light and variable winds in the surrounding region.

2        In the second fortnight of October 2016, short-duration thundery showers can be expected on four to six days, mostly in the late morning and early afternoon. In addition, widespread thundery showers with occasional gusty winds are forecast on two or three days between the pre-dawn hours and morning. Rainfall for October 2016 is expected to be slightly below normal.

3        During the period, the maximum daily temperature on most days is forecast to be around 33 or 34°C, and on a few days could reach a high of around 35°C. Warmer conditions are common during the Inter-Monsoon season when there is strong solar heating and the winds are generally light.

4        For updates of the daily weather and haze forecast, please visit our MSS website (www.weather.gov.sg), NEA website (www.nea.gov.sg), the haze microsite (www.haze.gov.sg) or download the myENV app, MSS’ Weather@SG app.

REVIEW: 1 – 16 October 2016

5         In the first fortnight of October 2016, Southwest Monsoon conditions prevailed over the region with the low level winds blowing predominantly from the west, and occasionally from the southwest. The prevailing winds during the review period were partly influenced by the presence of tropical storms in the northwestern Pacific Ocean and northern South China Sea.

6        Singapore experienced a few warm days in the first two weeks of October 2016. At the Changi climate station, the highest daily maximum temperature recorded was 34.6°C (on 11 October 2016). This record ties with the highest ever recorded daily maximum temperature for October (on 29 October 2002). As of 16 October 2016, the mean monthly temperature for October 2016 was 28.8°C, 1.2°C warmer than the long-term mean for October.

7        During the review period, Singapore’s rainfall on most days were from an eastward moving line of thunderstorms known as Sumatra squalls that developed over the western coast of Sumatra or the Strait of Malacca overnight. On the other days that rained, the thundery showers in the late morning and early afternoon were due to strong solar heating of land areas. Rainfall was heaviest on 3 October 2016 over the Buona Vista area where a total of 96.8mm of rainfall was recorded.

8       For the first fortnight of October 2016, rainfall was below average in the northwestern half of Singapore, and above average in the southeastern half of the island. The highest rainfall of 139.2mm (53% above average) was recorded around the Tanjong Katong area. Rainfall was lowest in the western part of the island around the Choa Chu Kang area where 65.8mm (39% below average) was recorded.FortnightRain_Anomaly_201610a

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

Mean daily maximum temperature 31.7 °C
Mean daily minimum temperature 24.7 °C
Mean monthly temperature 27.6 °C
Mean rainfall for the month 154.6 mm
Mean number of rain days 15
Highest monthly mean daily maximum temperature 33.0 °C (2002)
Lowest monthlymean daily minimum temperature 23.8 °C (1982)
Highest monthly rainfall 351.4 mm (2003)
Lowest monthly rainfall 10.8 mm (2002)