Category Archives: Regional Weather Review for Year 2014

January 28, 2015

Review of Regional Weather and Smoke Haze for Dec 2014

1. Review of Regional Weather Conditions in December 2014

1.1 Moderate Northeast Monsoon season was established in the region in December 2014, bringing dry and cool weather to most parts of the Mekong Sub-region of Cambodia, Lao PDR, Myanmar, northern Thailand and Vietnam. In the southern ASEAN region, the prevailing rainy season affected most parts of the southern ASEAN region.

1.2 Super Typhoon ‘Hagupit’ which was the most intense tropical cyclone of the year, developed to the east of the Philippines in the last week of November 2014. It strengthened as it tracked westwards, making landfall over the provinces of Samar and Masbate in the Philippines on 6 and 7 December 2014 respectively. ‘Hagupit’ weakened rapidly after making landfall and dissipated rapidly over the South China Sea, southeast of Vietnam. On 29 December 2014, another Tropical Storm ‘Jangmi’ affected the Philippines, making landfall over Mindanao. ‘Jangmi’ tracked across the Philippines before dissipating over South China Sea. Both ‘Hagupit’ and ‘Jangmi’ affected up to a million people, and destroying hundreds of houses along their path.

1.3 On 13 January 2015, Typhoon “Mekkhala” developed over the Western Pacific Ocean, and continued its westward track afecting the eastern part of Luzon and Visayas in the Philippines a few days later. Typhoon “Mekkhala” made landfall near eastern Samar, the Philippines on 17 January 2015, and weakened rapidly into a tropical depression as it moved north-eastwards, dissipating over water on 21 January 2015 away from Luzon Islands.

1.4 During the second half of December 2014, the strengthening of north-easterly winds over the South China Sea, or a monsoon surge, affected the region on a few occasions. The monsoon surges brought wet and windy conditions to parts of the southern ASEAN region. Continuous heavy showers of rain fell over most parts of Peninsular Malaysia, and led to severe flooding in the eastern coastal States of Terengganu, Pahang, and Kelantan with around 250,000 people displaced from their homes. Several districts in Indonesia and southern Thailand were also affected by floods due to the several days of continuous rainfall.

1.5 In December 2014, many parts of the southern ASEAN region received more than 100% of normal rainfall with the exception of southern Sumatra and western Borneo where less than 100% of normal rainfall was received. In contrast, most parts of the northern ASEAN region such as Thailand, Myanmar and Cambodia received less than 50% normal rainfall. Many parts of the Philippines received more than 125% of normal rainfall due to the passage of Super Typhoon ‘Hagupit’ and Tropical Storm ‘Jangmi’. The regional rainfall distribution for December 2014 is shown in Fig. 1A.

Fig. 1A: Percentage of Normal Rainfall for December 2014

2. Review of Land/Forest Fires and Smoke Haze Situation

2.1 Wet weather conditions in December 2014 continued to keep hotspot activities in the southern ASEAN region subdued. For the northern ASEAN region, the onset of the traditional dry season brought an increase in hotspot activities, mainly in Cambodia, Myanmar, Thailand and Vietnam. Satellite images depicting some of the hotspot activities over the ASEAN region in December 2014 are shown in Figs. 2A to 2E.

Fig. 2A: NOAA-18 satellite picture on 8 December 2014 shows subdued hotspot activities in Sumatra due to the prevailing wet weather.

Fig. 2B: NOAA-18 satellite picture on 9 December 2014 showing the emergence of increased hotspot activities in northern ASEAN.

Fig. 2C: NOAA-18 satellite picture on 15 December 2014 showing an increase in hotspot activities in Thailand due to the drier weather conditions.

Fig. 2D: NOAA-18 satellite picture on 24 December 2014 showing the occurrence of isolated hotspot activities in Myanmar.

Fig. 2E: NOAA-18 satellite picture on 27 December 2014 shows an increase in hotspots in the Cambodia.

2.2 The hotspot charts for December 2014 for

Cambodia, Myanmar, Thailand, Lao PDR and Vietnam;
Sumatra, Borneo and Peninsular Malaysia; and
Java, Sulawesi and the Philippines

are shown in Figs. 2F to 2H respectively

Fig. 2F: Hotspot Counts in Cambodia, Lao PDR, Thailand, Vietnam, Myanmar for December 2014.

Fig 2G: Hotspot Counts in Sumatra, Borneo and Peninsular Malaysia for December 2014.

Fig. 2H: Hotspot Counts in Java, Sulawesi, Philippines for December 2014.

December 16, 2014

Review of Regional Weather and Smoke Haze for Nov 2014

Print Version

1. Review of Regional Weather Conditions in November 2014

1.1 Inter-Monsoon conditions prevailed over the region for most parts of November 2014 before giving way to Northeast Monsoon conditions in late November 2014. The generally light and variable low level winds strengthened to blow predominantly from the northeast or northwest with the onset of the Northeast Monsoon season.

1.2 In November 2014, two tropical cyclones – ‘Nuri’ and ‘Sinlaku’ affected the equatorial region. ‘Nuri’ developed to the east-southeast of Guam in late October 2014 and intensified into Super Typhoon strength in early November 2014 before weakening and dissipating over the north-eastern Pacific Ocean on 6 November 2014. Tropical Storm ‘Sinlaku’ developed off the east coast of the Philippines in late November 2014. It intensified as it track northwestwards across the Philippines, and into over the South China Sea before dissipating as it made landfall over the south central coast of Vietnam on 30 November. ’Sinlaku’ brought heavy rains and strong winds to areas along its path.

1.3 As the region transitioned from the Inter-Monsoon to the Northeast Monsoon season, increased rainfall was experienced in the southern ASEAN region. In the second half of November 2014, increased convective activity in the South China Sea brought heavy rainfall to the eastern coastal states of Peninsular Malaysia which led to floods in Kelantan and Terengganu. For the northern ASEAN region, there was a decrease in rainfall and drier and cooler conditions were experienced.

1.4 In November 2014, many parts of the southern ASEAN region such as Sumatra and Peninsular Malaysia received more than 100% of normal rainfall. Less than 75% of normal rainfall was received in most parts of the northern ASEAN region while southern Philippines received more than 125% of normal rainfall. The regional rainfall distribution for November 2014 is shown in Fig. 1A.

Fig. 1A: Percentage of Normal Rainfall for December 2014. The rainfall data may be less representative for areas with low density of rainfall network.

2. Review of Land/Forest Fires and Smoke Haze Situation

2.1 Hotspot activities in the northern ASEAN region remained mostly subdued in November 2014. However, the transition to the drier weather conditions at the end of the month led to sporadic surges in hotspot activities observed in parts of Cambodia, Thailand and Vietnam.

2.2 In the southern ASEAN region, a brief period of drier weather in the first week of November 2014 led to the emergence of scattered hotspot activities in southern Sumatra and Kalimantan. Moderate smoke haze was also observed to emanate from these hotspots which led to the deterioration of air quality and visibility in parts of southern Sumatra. From the second week of November 2014, increased showers helped to subdue the hotspot activities in southern Sumatra and Kalimantan. Satellite images depicting some of the hotspot activities in the ASEAN region in November 2014 are shown in Figs. 2A to 2E.

Fig. 2A: NOAA-18 satellite picture on 3 November 2014 shows widespread smoke haze emanating from hotspots in southern Sumatra.

Fig. 2B: NOAA-18 satellite picture on 4 November 2014 shows scattered hotspots with smoke plumes and moderate smoke haze in southern Kalimantan.

Figure 2C: NOAA-18 satellite picture on 26 November 2014 shows few sporadic hotspot activities in Borneo with the increase in showers.

Fig. 2D: NOAA-18 satellite picture on 27 November 2014 shows subdued hotspot activities in Sumatra due to the return of shower activities.

Fig. 2E: NOAA-18 satellite picture on 28 November 2014 shows the emergence of hotspots in the northern ASEAN region.

2.3 The hotspot charts for December 2014 for

Cambodia, Myanmar, Thailand, Lao PDR and Vietnam;
Sumatra, Borneo and Peninsular Malaysia;

are shown in Figs. 2F to 2G respectively

Fig. 2F: Hotspot Counts in Cambodia, Lao PDR, Thailand, Vietnam, Myanmar for December 2014.

Fig 2G: Hotspot Counts in Sumatra, Borneo and Peninsular Malaysia for December 2016.

3. Status of El Niño/La Niña

3.1 The past two months have seen steady warming of the tropical Pacific Ocean resulting in the sea-surface temperatures (SST) reaching weak El Niño levels. However the atmosphere above it has yet to respond fully, with only some atmospheric indicators (e.g. large-scale change in upper and low level winds) reaching El Niño levels. As other indicators of atmospheric response to El Niño such as cloudiness and rainfall are still within neutral thresholds, the El Niño Southern Oscillation (ENSO) is not yet considered to be fully established.

3.2 Climate model outlook and expert assessment suggest further intensification of conditions likely. As such, El Niño is predicted to become fully established before the end of February 2015 with about 70% chance of a weak El Niño event occurring.

3.3 Typically the impact from El Niño for the Southeast Asia region is drier than average rainfall conditions, especially for the southern and eastern parts during June to October. More locally-specific impact differs from place to place and for different seasons.

3.4 As we are within the Northeast Monsoon season (Dec – Feb), where El Niño is not known to have much impact on the western part of the Maritime Continent, the possibility of a weak El Niño developing in the next one to two months do not pose significant risks of extended periods of drier and warmer conditions in this part of Southeast Asia.

November 13, 2014

Review of Regional Weather and Smoke Haze for Oct 2014

Print Version

1. Review of Regional Weather Conditions in October 2014

1.1 The Southwest Monsoon season continued to prevail in the first half of October 2014 and gradually transitioned to the Inter-Monsoon season in the second half of the month.

1.2 Two typhoons and one tropical storm affected the north-western Pacific Ocean in October 2014, namely Typhoon Phanfone, Typhoon Vongfong and Tropical Storm Nuri. Typhoon Phanfone, developed in the last week of September 2014 and made landfall over Honshu, Japan on 04 October 2014 resulting in seven deaths and more than 62 injured. Shortly after Typhoon Phanfone made landfall, the wrath of Typhoon Vongfong swept across the islands of Kyushu and Honshu, Japan on 13 and 14 October 2014 respectively, bringing strong winds and heavy rainfall to islands. In addition, Typhoon Vongfong led to the cancellation of a few hundred flights to and from Japan.

1.3 The presence of the monsoon trough over the northern ASEAN region during the first fortnight of October 2014 enhanced convective activities there and brought more than 100% of normal rainfall to parts of the Philippines, Laos PDR, Thailand and Vietnam.

1.4 Generally wet conditions affected the southern ASEAN region during the month. Brief periods of drier weather condition were observed in parts of southern ASEAN region, in particular, in Java island, southern Kalimantan and southern Sumatra. Less than 75% of normal rainfall was received in southern parts of Kalimantan and Sumatra, Java Island and Sulawesi while more than 125% of normal rainfall was felt in northern Sumatra, Peninsular Malaysia and Sabah in East Malaysia. The regional rainfall distribution for October 2014 is shown in Fig. 1A.

Fig. 1A: Percentage of Normal Rainfall for October 2014. The rainfall data may be less representative for areas with low density of rainfall network.

2. Review of Land/Forest Fires and Smoke Haze Situation

2.1 In the northern ASEAN region, wet weather conditions continued to keep the hotspot activities subdued. In the southern ASEAN region, dry weather conditions affected mainly the southern half of Sumatra and Kalimantan during the first two weeks of October 2014 and again in the last week of October 2014. Persistent hotspots with smoke plumes and moderate to dense smoke haze were observed emanating from the hotspots in southern Sumatra and Kalimantan. The widespread smoke haze was blown by the prevailing winds which led to the deterioration in the air quality and visibility in parts of central and southern Sumatra, and Kalimantan. Smoke haze was also transported by the prevailing winds to affect parts of Peninsular Malaysia and Singapore on some days in October 2014. Satellite images depicting some of the hotspot activities in the ASEAN region in October 2014 are shown in Figs. 2A to 2E.

Fig. 2A: NOAA-18 satellite picture on 01 October 2014 showing hotspots in southern Sumatra. Smoke plumes were visible in the satellite imaginary.

Fig. 2B: NOAA-18 satellite picture on 02 October 2014 showing widespread moderate to dense smoke haze emanating from clusters of hotspots in Kalimantan.

Figure 2C: NOAA-18 satellite picture on 09 October 2014 showing persistent smoke haze from hotspots in southern Sumatra.

Fig. 2D: NOAA-18 satellite picture on 10 October 2014 showing widespread smoke haze in southern Kalimantan.

Fig. 2E: NOAA-18 satellite picture on 12 October 2014 showing widespread smoke haze affecting most parts of Kalimantan.

2.3 The hotspot charts for October 2014 for

Cambodia, Myanmar, Thailand, Lao PDR and Vietnam;
Sumatra, Borneo and Peninsular Malaysia;

are shown in Figs. 2F to 2G respectively

Fig. 2F: Hotspot Counts in Cambodia, Lao PDR, Thailand, Vietnam, Myanmar for October 2014.

Fig 2G: Hotspot Counts in Sumatra, Borneo and Peninsular Malaysia for October 2016.

3. Status of El Niño/La Niña

3.2 Typically the impact from El Niño for the Southeast Asia region is drier than average rainfall conditions for the southern and eastern parts of the region in June to October. More locally-specific, the impact differs from place to place and for different seasons.

3.3 During the Northeast Monsoon season, the El Niño is known to have little impact in the western part of the Maritime Continent, the possibility of a weak El Niño developing in the next one to two months is not expected to pose significant risks of extended periods of drier and warmer conditions in the ASEAN region.

October 13, 2014

Review of Regional Weather and Smoke Haze for Sep 2014

Print Version

1. Review of Regional Weather Conditions in September 2014

1.1 Weak Southwest Monsoon conditions continued to prevail in the ASEAN region in September 2014 with low level winds blowing mostly between the southeast or southwest.

1.2 The Northwestern Pacific Ocean experienced a total of 6 tropical cyclones in September 2014. Two of these tropical cyclones, namely Typhoon “Kalmaegi” and Tropical Storm “Fung-Wong” affected the northern ASEAN region. Typhoon “Kalmaegi” which developed to the northeast of Palau on 10 September 2014 intensified rapidly as it tracked westwards across Luzon, the Philippines before eventually making landfall over Hainan island on 16 September 2014. Typhoon “Kalmaegi” brought strong winds and heavy rainfall to the areas along its path which resulted in several dozens of flight delays and cancellations in Hong Kong and China, and floods in parts of Philippines and Vietnam. Tropical Storm “Fung-Wong” developed to the west of the Philippines on 17 September 2014. It tracked northwestwards and made landfall over northern Luzon in the Philippines and intensified as it continued its track northwest over the South China Sea. “Fung-Wong” weakened as it made landfall over Shanghai on 23 September 2014.

1.3 The presence of tropical cyclones in the surrounding region enhanced convective activities in the northern ASEAN region with 125% of normal rainfall received in some parts of the Philippines, Laos PDR and Thailand. In contrast, the southern ASEAN region experienced mostly dry weather conditions interspersed with occasional shower activities for September 2014. Many areas in the southern ASEAN region received less than 50% of normal rainfall. The regional rainfall pattern for September 2014 is shown in Fig. 1A.

Fig. 1A: Percentage of Normal Rainfall for September 2014. The rainfall data may be less representative for areas with low density of rainfall network.

2. Review of Land/Forest Fires and Smoke Haze Situation

2.1 In the northern ASEAN region, hotspot activities were generally subdued due to wet weather conditions. Sporadic hotspots were detected in Thailand and Vietnam during occasional brief periods of drier weather.

2.2 In the southern ASEAN region, dry weather conditions, in particular in the southern half of Sumatra and Kalimantan led to escalations in hotspot activities during the month. Persistent hotspots with smoke plumes and moderate to dense smoke haze were observed mostly over southern Sumatra and Kalimantan on several days. The widespread smoke haze from these fires led to a deterioration in the air quality and visibility in parts of central and southern Sumatra, and Kalimantan. In addition, the smoke haze was transported by the prevailing low level winds to affect Peninsular and East Malaysia and Singapore on several occasions in September 2014, with air quality in the unhealthy range on some days. Satellite images depicting some of the hotspot activities in the ASEAN region in September 2014 are shown in Figs. 2A to 2E.

Fig. 2A: NOAA-18 satellite picture on 13 September 2014 showing hotspot activities and smoke haze in southern Sumatra.

Fig. 2B: NOAA-18 satellite picture on 17 September 2014 showing moderate to dense smoke haze in parts of Kalimantan.

Figure 2C: NOAA-18 satellite picture on 24 September 2014 showing widespread smoke haze emanating from clusters of hotspots in southern Kalimantan.

Fig. 2D: NOAA-18 satellite picture on 25 September 2014 showing widespread moderate to dense smoke haze in southern Sumatra.

Fig. 2E: NOAA-18 satellite picture on 26 September 2014 showing widespread smoke haze in southern Sumatra.

2.3 The hotspot charts for September 2014 for

Cambodia, Myanmar, Thailand, Lao PDR and Vietnam;
Sumatra, Borneo and Peninsular Malaysia;

are shown in Figs. 2F to 2G respectively

Fig. 2F: Hotspot Counts in Cambodia, Lao PDR, Thailand, Vietnam, Myanmar for September 2014.

Fig 2G: Hotspot Counts in Sumatra, Borneo and Peninsular Malaysia for September 2014.

3. Status of El Niño/La Niña

3.1 The tropical Pacific Ocean is currently in neutral (neither El Niño nor La Niña) conditions. However, renewed signs of warming of sea surface temperatures there have been observed in September (Figure 3A) following the easing in July (Figure 3B). With most global climate models forecasting the continued warming of the tropical Pacific Ocean in the coming months (Figure 3C), a weak El Niño is still likely to develop towards the end of the year. There is now about 60% chance of El Niño occurring in October-November-December season (Figure 3D) and this is down from 70-80% stated in earlier predictions.

3.2 Typically the impact from El Niño for the Southeast Asia region is drier than average rainfall conditions, especially for the southern and eastern parts during June to October (Figure 3E). More locally-specific impact differs from place to place and for different seasons. As we are entering the inter-monsoon season in October, and with the possibility of a weak El Niño developing in the last quarter of 2014, the risks of occasional extended periods of drier and warmer conditions cannot yet be ruled out.

September 13, 2014

Review of Regional Weather and Smoke Haze for Aug 2014

Print Version

1. Review of Regional Weather Conditions in August 2014

1.1 Southwest Monsoon conditions continued to prevail in August 2014. In the northern ASEAN region of Cambodia, Laos PDR, Myanmar, Thailand, Vietnam and the Philippines, the traditional rainy season. For the southern ASEAN region, generally wet weather conditions with brief periods of drier weather conditions prevailed.

1.2 One typhoon affected the north-western Pacific Ocean during this month. Typhoon “Halong” developed to the east of the Philippines, tracked towards northwards and made landfall in Japan on 8 August. The presence of Typhoon “Halong” enhanced convective activities in the equatorial region which resulted in the development of extensive rain clouds, bringing wet weather to most parts of the southern ASEAN region during the first half of the month.

1.4 During the month, most parts of the ASEAN region received more than 75% of normal rainfall with the exception of Kalimantan and western Java where less than 50% of normal rainfall was received. The regional rainfall pattern for August 2014 is shown in Figure 1A.

Fig. 1A: Percentage of Normal Rainfall for August 2014. The rainfall data may be less representative for areas with low density of rainfall network.

2. Review of Land/Forest Fires and Smoke Haze Situation

2.1 Shower activities have helped to subdue hotspot activities in most parts of the southern ASEAN region during the month. However, elevated hotspot activities were detected mainly over Borneo and Sumatra during periods of drier weather conditions. Scattered hotspots with smoke haze were detected mainly over western and central Kalimantan. In Sumatra, isolated hotspots with localized smoke plumes were detected mainly in the southern half of Sumatra.

2.2 In the northern ASEAN region, the prevailing rainy season continued to keep hotspot activities subdued. Sporadic hotspots were detected mainly in Vietnam during occasional brief dry periods. Satellite images depicting some of the hotspot activities over the ASEAN region in August 2014 are shown in Figs. 2A to 2E.

Fig. 2A: NOAA-18 satellite picture on 03 August 2014 showing moderate smoke haze from scattered hotspots in west Kalimantan.

Fig. 2B: NOAA-18 satellite picture on 04 August 2014 showing smoke plumes emanating from some of hotspots in Riau.

Figure 2C: NOAA-18 satellite picture on 16 August 2014 showing an increase in hotspot activities in southern Sumatra due to drier weather conditions.

Fig. 2D: NOAA-18 satellite picture on 27 August 2014 showing smoke haze emanating from scattered hotspots over western and southern Borneo.

Fig. 2E: NOAA-18 satellite picture on 30 August 2014 showing isolated hotspots with localised smoke plumes in central Kalimantan.

2.3 The hotspot charts for August 2014 for

Cambodia, Myanmar, Thailand, Lao PDR and Vietnam;
Sumatra, Borneo and Peninsular Malaysia;

are shown in Figs. 2F to 2G respectively

Fig. 2F: Hotspot Counts in Cambodia, Lao PDR, Thailand, Vietnam, Myanmar for August 2014.

Fig 2G: Hotspot Counts in Sumatra, Borneo and Peninsular Malaysia for August 2014.

3. Status of El Niño/La Niña

3.1 Following the slight easing of the tropical Pacific Ocean warming during the month of July, especially over the Niño3.4 region, August has seen temperature anomalies gradually increasing again. Expert assessment and most climate models predict this warming to continue, and that El Niño of weak strength is likely to develop in the last quarter of 2014. There is now about 60% chance of El Niño occurring in September-October-November season and this is down from 70-80% stated in June’s and July’s predictions.

3.2 Despite the observed warming over the tropical Pacific Ocean over the last few months, a number of atmospheric indicators of the El Niño, such as wind flow and cloudiness, have remained largely neutral. A plausible explanation for the lack of atmospheric response is that the warming has occurred over almost the entire tropical Pacific Ocean, including the sea areas in our region. During a typical El Niño development, warming is observed mostly in the eastern and central parts of the tropical Pacific Ocean.

3.3 With the forecast of a weak El Niño in the last quarter of the year, it should be noted that the El Niño is known to have relatively less impact on weather patterns in Singapore and the nearby region during the Northeast Monsoon season (typically from late November to March). The risk of drier weather conditions due to the El Niño is thus expected to be lower towards the end of the year.

3.4 Typically the impact from El Niño for the Southeast Asia region is drier than average rainfall conditions, especially for the southern and eastern parts (Figure E). More locally-specific impact differs from place to place and for different seasons. As the Southwest Monsoon season continues to prevail in the region, and with the possibility of a weak El Niño developing in the last quarter of 2014, the risks of occasional extended periods of drier and warmer conditions cannot yet be ruled out.

August 19, 2014

Review of Regional Weather and Smoke Haze for Jul 2014

Print Version

1. Review of Regional Weather Conditions in July 2014

1.1 Southwest Monsoon conditions continued to prevail in July 2014 with low level winds over the region blowing mostly from the southeast or southwest. Rain bands from tropical cyclones during the first half of the month led to extensive rain clouds over most parts of the ASEAN region. However, the northward migration of the monsoon rain belt accompanied with an intensification of typhoon activities in the Western Pacific Ocean and South China Sea during the second half of the month brought dry weather conditions over the southern ASEAN region.

1.2 he western Pacific Ocean and northern South China Sea experienced 4 tropical cyclones in July 2014, namely Typhoon “Neoguri”, Typhoon “Rammasun”, Typhoon “Matmo” and Severe Tropical Storm “Nakri”. On 10 July 2014, Typhoon “Rammasun” developed to the southeast of the Mariana islands, tracked westwards and made landfall over Luzon island, the Philippines. “Rammasun” intensified as it entered into the South China Sea before making landfall over Hainan Island and moving across northern Vietnam on 18 and 19 July 2014 respectively. Typhoon “Rammasun” resulted in widespread damage, killing at least 200 people and injuring hundreds more.

1.3 During the month, many parts of the Mekong Sub-region received more than 125% of normal rainfall due to the presence of the monsoon rain belt in the northern hemisphere. In contrast, most parts of the southern ASEAN region received less than 100% of normal rainfall with the exception of central Sumatra and western Java where more than 125% of normal rainfall was received. The regional rainfall pattern for July 2014 is shown in Figure 1A.

Fig. 1A: Percentage of Normal Rainfall for July 2014. The rainfall data may be less representative for areas with low density of rainfall network.

2. Review of Land/Forest Fires and Smoke Haze Situation

2.1 The prevailing rainy season continued to help keep hotspot activities subdued in the northern ASEAN region. Few to scattered sporadic hotspots were detected mostly in Myanmar and Vietnam during brief periods of drier weather.
2.2 Wet weather conditions during the first half of the month helped to subdue hotspot activities in the southern ASEAN region. However, a period of drier weather conditions led to an increase in hotspot activities mainly over Borneo and the northern half of Sumatra during the second half of the month. Scattered hotspots with localized smoke plumes were detected over the northern half of Sumatra between 18 and 29 July 2014. During this period, some areas along the western coast of Peninsular Malaysia reported unhealthy levels of Air Pollutant Index (API) between 100 and 200. Port Klang had the highest API of 139 on 21 July 2014. Similarly, scattered hotspots with moderate smoke haze were also detected mainly in western Borneo. The smoke haze led to a drastic drop in air quality mainly in Sarawak with unhealthy readings recorded at Sibu, Samarahan and Sri Aman on 28 July 2014. The return of shower activities towards the end of the month helped to ease the smoke haze situation in the region. Satellite images depicting some of the hotspot activities over the ASEAN region in July 2014 are shown in Figs. 2A to 2E.

Fig. 2A: NOAA-18 satellite picture on 18 July 2014 showing slight to moderate haze from some of the hotspots in central Sumatra.

Fig. 2B: NOAA-18 satellite picture on 20 July 2014 showing smoke haze from Riau affecting parts of the Strait of Malacca and western Peninsular Malaysia.

Figure 2C: NOAA-18 satellite picture on 21 July 2014 showing moderate smoke haze over Riau spreading across the Strait of Malacca to affect the west coastal states of Peninsular Malaysia.

Fig. 2E: NOAA-18 satellite picture on 26 July 2014 showing moderate smoke haze emanating from hotspots in West Kalimantan.

Fig. 2D: NOAA-18 satellite picture on 24 July 2014 showing scattered hotspots with localised smoke haze over western Kalimantan .

2.3 The hotspot charts for July 2014 for

Cambodia, Myanmar, Thailand, Lao PDR and Vietnam;
Sumatra, Borneo and Peninsular Malaysia;
Java, Sulawesi and the Philippines;

are shown in Figs. 2F to 2H respectively

Fig. 2E: NOAA-18 satellite picture on 26 July 2014 showing moderate smoke haze emanating from hotspots in West Kalimantan.

Fig. 2F: Hotspot Counts in Cambodia, Lao PDR, Thailand, Vietnam, Myanmar for July 2014.

Fig 2G: Hotspot Counts in Java, Sulawesi, Philippines for July 2014.

3. Status of El Niño/La Niña

3.1 The tropical Pacific Ocean surface temperatures have continued to warm but gradually eased in recent weeks, slowing down the development of El Niño conditions. However, with most global climate models forecasting the continued warming of the tropical Pacific Ocean in the coming months, a weak to moderate El Niño is still likely to develop in the last quarter of 2014 .

3.3 In the last few months the sea surface temperatures in our region have been warmer than normal, leading to increased convection and formation of rain clouds. This has contributed to the relatively wet weather conditions in Singapore and the surrounding region during the current Southwest Monsoon season.

3.4 With the forecast of a weak to moderate El Nino in the last quarter of the year, it should be noted that the El Niño is known to have relatively less impact on weather patterns in Singapore and the nearby region during the Northeast Monsoon season (typically from late November to March). The risk of drier weather conditions due to the El Niño is thus expected to be lower towards the end of the year.

3.5 Typically the impact from El Niño for the Southeast Asia region is drier than average rainfall conditions, especially for the southern and eastern parts. More locally-specific impact differs from place to place and for different seasons. As the Southwest Monsoon season continues to prevail in the region, and with the possibility of a weak to moderate El Niño, the risks of occasional extended periods of drier and warmer conditions cannot yet be ruled out.