Review of Regional Weather and Smoke Haze for Jun 2015

1.   Review of Regional Weather Conditions in June 2015

1.1    The monsoon trough has migrated to the northern ASEAN region, with its position hovered mainly along the 10 N latitude line. The monsoon trough brought persistent shower activities over most parts of northern ASEAN.

1.2    Southwest Monsoon conditions, characterised by low level winds predominantly from the southeast or southwest, onset in the southern ASEAN region from the second half of June 2015. Wet weather conditions prevailed over the region in the first half of June 2015 and transited gradually to drier weather conditions with the onset of the traditional dry Southwest Monsoon season.

1.3    The rainfall over the southern ASEAN region in June has been lower than usual, which can partly be attributed to the prevailing moderate El Niño conditions in the equatorial Pacific Ocean which are likely to further develop in the months ahead. Sumatra, Java and southern Kalimantan received less than 50-75% of the normal rainfall; this is a typical precipitation pattern observed in southern ASEAN during a moderate to strong El Niño event. For the northern ASEAN region, below-normal rainfall has also been recorded in most parts except for central Thailand. The regional rainfall distribution for June 2015 is shown in Fig. 1A.


Fig. 1A: Percentage of Normal Rainfall for June 2015


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

2.1    In the northern ASEAN region, hotspot activities continued to be subdued by the prevailing wet weather conditions.

2.2    In the southern ASEAN region, increased hotspot activities were detected during the period of drier weather in the second half of June. Persistent hotspots were observed on several days mostly in the provinces of Riau and Jambi in Sumatra. Smoke plumes and moderate haze were seen emanating from these hotspots.

2.3    In June 2015, most parts of Kalimantan were affected by showers. In the second half of June 2015, a period of drier weather led to the occurrence of isolated hotspots with localized smoke plumes in parts of western Kalimantan. Satellite images depicting some of the hotspot activities over the ASEAN region in June 2015 are shown in Figs. 2A to 2E.


Fig. 2A: NOAA-18 satellite image on 25 June 2015 shows hotspot activities with smoke plumes and haze in central Sumatra .


Fig. 2B: NOAA-18 satellite picture on 26 June 2015 shows visible smoke plumes emanating from hotspots in central Sumatra.

Fig. 2C: NOAA-18 satellite picture on 26 June 2015 shows isolated hotspots in Peninsular Malaysia.


Fig. 2D: NOAA-18 satellite picture on 27 June 2015 shows smoke plumes and moderate haze emanating from the same hotspots in central Sumatra since 25 June 2015.

Fig. 2E: NOAA-18 satellite picture on 27 June 2015 shows hotspots and isolated smoke plumes in western Kalimantan.


2.3    The hotspot charts for June 2015 for

  1. Cambodia, Myanmar, Thailand, Lao PDR and Vietnam;
  2. Sumatra, Borneo and Peninsular Malaysia; and
  3. 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 June 2015.


Fig 2G: Hotspot Counts in Sumatra, Borneo and Peninsular Malaysia for June 2015.


Fig. 2H: Hotspot Counts in Java, Sulawesi, Philippines for June 2015.