Monthly Archives: January 2014

Dry conditions to persist for at least the next one to two weeks

Singapore, 29 January 2014 – Singapore is currently in the dry phase of the Northeast Monsoon season, typically characterised by drier and cooler weather and generally windy conditions. The onset of this dry phase is earlier than usual this year, leading to fewer rain days and significantly lower rainfall this month. The last few weeks have also been marked by a spell of cooler than normal minimum temperatures.

2The rainfall total for January (1 to 28 Jan 2014) ranged from 20 to 125 mm (45-90% below the long-term average) across the island. At the Changi climate station, 75.4mm of rainfall and five rain days were recorded over this period, compared to the long-term average rainfall of 242.3mm and 15 rain days respectively for January^[1]. The last recorded rainfall was 0.8mm in Jurong on 16 January 2014.

3Since 14 January 2014, daily minimum temperatures of between 21 and 22 degrees Celsius were recorded in various parts of the island. The cooler than normal temperatures are due to a surge of cold winds from a high pressure system over China, blowing towards Singapore and the region. Singapore last experienced a similar spell of cool minimum temperatures during the Northeast Monsoon in early 2009.

4In the coming days, the current cool daily minimum temperatures are expected to increase slightly to the long term average value of around 23.5 degrees Celsius for January and February. However, the current dry and occasionally windy conditions are forecast to persist for at least the next one to two weeks. During this period, slight haze may occur under light wind conditions on a few mornings.

5For the Lunar New Year holiday period, the weather is expected to be fair and occasionally windy, with the daily temperature ranging between 23 and 31 degrees Celsius.

Singapore is currently in the dry phase of the Northeast Monsoon season which is characterised by generally windy conditions and drier weather. The dry phase is expected to last till end February / early March 2014.

During this period, fewer rain days and lower rainfall can be expected. On some days, particularly in the morning when winds are light, slightly hazy conditions can be expected. The haze will clear with the strengthening of winds later in the day.

For this weekend (25 – 26 January 2014), partly cloudy and occasional windy conditions can be expected. Occasional slight haze can also be expected, mainly in the morning. The air quality is expected to remain in the Good band.

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Singapore, 18 January 2014 – Mount Sinabung, located 80km west of Medan, North Sumatra, and 650km from Singapore, has been in a state of intermittent volcanic activity since 15 September 2013. To date, Singapore has not been affected by the volcanic ash from this volcanic activity.

2The Meteorological Service Singapore (MSS) has been closely monitoring the situation. There has been an intensification of volcanic activity in recent days.

3Dispersion model simulations by the MSS as well as the Darwin Volcanic Ash Advisory Centre indicate that over the next one to two days, volcanic ash is expected to move south, but will be confined within the northern half of Sumatra. The likelihood of volcanic ash affecting Singapore is low and the 24-hr PSI is expected to remain in the Good band. Should some volcanic ash reach Singapore under current conditions, there may be a slight deterioration in air quality. MSS will continue to monitor the situation and will provide updates on developments.

4The most frequent health problems that occur among people who have been exposed to volcanic ash are acute respiratory symptoms, stress and irritations of eyes (contact lens users are at risk) and skin, and exacerbation in people with cardio-respiratory problems. People with existing lung diseases such as asthma, bronchitis or emphysema, as well as older adults and children are also sensitive towards the exposure of volcanic ash. The severity of these problems is however, affected by the concentration of ash and the duration of exposure to ash. The amount of ash that may reach Singapore is likely to be small and the duration relatively short, posing little or no health risk to the public.

5The public may refer to the NEA website for regular updates on the situation. The 24-hr PSI is used as the reference to measure air quality during a volcanic ash situation as the volcanic ash particles^[1] are in the PM₁₀^[2] range and included in the PSI. The public may access PSI updates through the following channels:

• NEA Twitter
• NEA myENV App on iPhone and Android

^[1] Volcanic ash particles are pieces of pulverized rock like sand or rock dust made of silica with some amounts of potassium, aluminum and iron. Trace quantities of other metals may also be present.

^[2] Particulate matter of 10 microns or smaller in size.

^[3] Particulate matter of 10 microns or smaller in size

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