Monthly Archives: September 2015

Short-duration thundery showers on some days

Advisory

Singapore, 16 September 2015 – Southwest Monsoon conditions are forecast to prevail with low level winds blowing predominantly from southeast or south-southwest.

2. In the second fortnight of September 2015, short duration thundery showers are likely on 3 to 5 days, mostly in the late morning and early afternoon. In addition, thundery showers with gusty winds due to Sumatra squalls can be expected on 1 or 2 days in the pre-dawn hours and early morning. Maximum temperatures of around 34 degrees Celsius can be expected on a few days.

3. As dry weather conditions are expected to persist in the region, Singapore could experience hazy conditions on some days if unfavourable winds blow in smoke haze from the surrounding region.

4. The rainfall for September 2015 is expected to be below normal.

Review of 1 – 15 September 2015

5. Southwest Monsoon conditions prevailed in the first fortnight of September 2015. During the period, the low level winds blew from the southeast or southwest.

6. In the first fortnight of September 2015, Singapore experienced hazy conditions due to smoke haze from fires in Sumatra that were blown in by the prevailing south to southwesterly winds. Thundery showers affected the island between the late morning and early afternoon on a few days. The highest daily total rainfall recorded for the period was 80mm on 9 September 2015 in the western part of Singapore around Chua Chu Kang. In the first two weeks of September 2015, the highest daily maximum temperature recorded ranged between 34.2 and 34.7 degrees Celsius, and on a few wet days, the lowest daily minimum temperature recorded was between 22.4 and 22.7 degrees Celsius.

7. During the review period, most parts of Singapore received below average rainfall. The lowest rainfall of 10mm and 34mm (60 to 90% below average) was recorded over the northern and central parts of Singapore around Yishun and Serangoon. Rainfall was highest over the western part the island around Jurong and Tuas, where 111mm to 171mm (60 to 90% above average) of rain was recorded.

STATISTICS FOR SEPTEMBER since 1869 (CLIMATE STATION)

Average rainfall for the month — 168.8 mm
Highest rainfall ever recorded — 440.4 mm (1988)
Lowest rainfall ever recorded — 23.7 mm (1994)
Average number of rain days — 14
Average daily maximum temperature — 30.9 degrees Celsius
Average daily minimum temperature — 24.3 degrees Celsius

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Singapore, 14 September 2015 – The Meteorological Service Singapore (MSS) has launched a mobile weather website to make it easier for users of mobile devices to obtain weather information on the go. The mobile website, accessible at weather.gov.sg/mobile, gives users access to the latest national weather forecasts and warnings, and island-wide observations of rainfall, temperature, humidity and wind.

2.  The website can detect a user’s location to automatically display the 2-hour nowcast for his current location. Favourite nowcast locations can also be set up for quick access. The website includes MSS’ popular rain radar information where users can view the current rain areas over the island and up to 240 km away from Singapore.

3.  The new mobile weather website replaces MSS’ Weather@SG which has been in service since 2011. MSS is currently developing weather apps for the Android and Apple iOS platforms, which are scheduled to be released later this year.

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Singapore, 3 September 2015 – Singapore has been experiencing hazy conditions since early this morning. As at 2pm today, the 24-hr PSI was 80-88, in the Moderate range and the 1-hour PM2.5 was 47-69 µg/m3. The air quality is expected to move into the low end of the Unhealthy range over the next few hours.

2 The haziness is due to the spread of smoke haze from Sumatra under weakening wind conditions over Singapore. The latest satellite image today shows persisting widespread moderate to dense smoke haze in central and southern Sumatra. For the rest of today, the current hazy conditions are expected to persist. The 24-hour PSI for today is expected to be in the low end of the Unhealthy range.

3  For the next few days, the hotspot and haze situation in Sumatra is not likely to change significantly under the current dry weather conditions. Occasional hazy conditions can thus be expected to persist for the next one to two days. Conditions will improve should the wind speeds pick up. However, the haze situation in Singapore may also deteriorate if the prevailing winds shift to blow from the south or southwest.

4 The Chief Executive Officer of the National Environment Agency (NEA), Mr Ronnie Tay, wrote to his Indonesian counterpart two days ago to register Singapore’s concerns over the situation and to seek an urgent update on the ground situation. NEA also reiterated Singapore’s offer to Indonesia of its assistance package to help combat the haze problem there. NEA had first contacted them two weeks ago in view of the deteriorating hotspot situation in Sumatra then, and will continue to be in touch with them going forward.

5  With the escalation of hotspot activities over Sumatra, the ASEAN Specialised Meteorological Centre (ASMC) advised on 1 September 2015 that the conditions/trigger points for Alert Level 3¹ for Sumatra had been met. Alert Level 3 is raised when there are 250 or more hotspots detected on two consecutive days with dry weather conditions persisting and prevailing winds blowing towards other ASEAN countries. A total of 395 hotspots were detected in Sumatra yesterday.

6 The health impact of haze is dependent on one’s health status, the PSI level, and the length and intensity of outdoor activity. Reducing outdoor activities and physical exertion can help limit the ill effects from haze exposure. Given the air quality forecast for the next 24 hours, healthy persons should reduce prolonged or strenuous outdoor physical exertion. The elderly, pregnant women and children should minimise prolonged or strenuous outdoor physical exertion, while those with chronic lung or heart disease should avoid prolonged or strenuous outdoor physical exertion. Persons who are not feeling well, especially the elderly and children, and those with chronic heart or lung conditions, should seek medical attention.

7  In response to public queries on participating in outdoor activities and open-air meetings, NEA advises the public to refer to the Ministry of Health’s (MOH) advisory (http://bit.ly/1NOA1WJ), as well as NEA’s daily haze situation update.

8  NEA will continue to monitor the situation closely and issue updates as the need arises. For more information, visit our NEA website (www.nea.gov.sg), the haze microsite (www.haze.gov.sg), follow us on NEA Facebook (www.facebook.com/NEASingapore) and NEA Twitter (@NEAsg), or download the myENV app.

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¹The ASEAN Specialised Meteorological Centre (ASMC) has a regional warning system for the fire and haze situation based on three levels of alert. Alert Level 1 signifies the start of the dry season; Level 2 is activated when 150 hotspots or more are detected on two consecutive days, with dry weather conditions persisting and prevailing winds blowing towards other ASEAN countries. Alert Level 3 is when there are 250 or more hotspots detected on two consecutive days with dry weather conditions persisting and prevailing winds blowing towards other ASEAN countries. The alert levels are issued to the interim ASEAN Coordinating Centre for Transboundary Haze Pollution at the ASEAN Secretariat, which in turn disseminates it to the ASEAN member countries.

Slight to moderate haze conditions on some days if winds shift to blow from south or southwest

Advisory

Singapore, 1 September 2015 – Southwest Monsoon conditions are forecast to prevail during the first fortnight with low level winds blowing predominantly from southeast or south-southwest.

2.   In the first fortnight of September 2015, some warm days can be expected with maximum temperatures of around 34 degrees Celsius. Short-duration thundery showers are likely on 3 to 5 days, mostly in the late morning and early afternoon. In addition, thundery showers with gusty winds due to Sumatra squalls can be expected on 1 or 2 days in the morning.

3.   As periods of consecutive dry days can be expected over the region, Singapore could experience slight to moderate hazy conditions on a few days if the prevailing winds shift to blow from the south or southwest.

4.  The rainfall for the first fortnight of September 2015 is expected to be below-normal.

Review of 1 – 31 August 2015

5.   Southwest-Monsoon conditions prevailed in August 2015. During the period, the low level winds blew from the southeast or south-southwest.

6.   In the first fortnight of August 2015, Singapore experienced wet weather conditions on most days. Thundery showers with gusty winds affected the island on a few mornings due to the passage of a Sumatra squall during the period. In the last two weeks of the month, the weather in Singapore was mostly dry and warm. For August 2015, the highest daily maximum temperature recorded on some days was between 34.5 and 34.8 degrees Celsius. On a few wet days during the month, the lowest daily minimum temperature recorded was between 21.6 and 21.9 degree Celsius.

7.   For several days in the second half of August 2015, Singapore experienced slightly hazy conditions due to smoke haze from fires in Sumatra that were blown in by the prevailing south to southwesterly winds.

8.  In August 2015, most parts of Singapore received below-average rainfall. The lowest rainfall of 78mm and 102mm (45 to 60% below average) was recorded over the northern part of Singapore around Admiralty. Rainfall was highest over the southern and eastern parts the island around Newton and Simei respectively, where 220mm to 244mm (15 to 30% above average) of rain was recorded.

STATISTICS FOR SEPTEMBER since 1869 (CLIMATE STATION)

Average rainfall for the month — 168.8 mm
Highest rainfall ever recorded — 440.4 mm (1988)
Lowest rainfall ever recorded — 23.7 mm (1994)
Average number of rain days — 14
Average daily maximum temperature — 30.9 degrees Celsius
Average daily minimum temperature — 24.3 degrees Celsius

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