Review of Regional Weather and Smoke Haze for Dec 2015
1. Review of Regional Weather Conditions in December 2015
1.1 The Northeast Monsoon season prevailed in December 2015 with the monsoon rain in the equatorial region between 5 N and 5 S. In the northern ASEAN region, the dry season onset in mid-December 2015 while scattered shower activities and north-easterly winds affected most parts of the southern ASEAN region including Malaysia, Singapore and Indonesia.
1.2 Typhoon Melor, which developed over the western Pacific Ocean in the second week of December 2015 made landfall over Bulusan in southern Luzon on 14 December 2015. It brought strong winds and heavy rain to the affected areas. Typhoon Melor continued to track westward over the South China Sea before weakening into a tropical depression two days later.
1.3 Likely to be associated with the strong El Niño condition which peaked in December 2015, most of the region experienced drier than usual weather conditions. Above-normal rainfall was received in northern parts of Philippines due to Typhoon Melor, and near-normal rainfall was received in the near-equatorial region, in particularly over Peninsular Malaysia, Singapore, southern Sumatra and western Borneo Island. The regional rainfall distribution for December 2015 is shown in Figure Fig. 1A.
2. Review of Land/Forest Fires and Smoke Haze Situation
2.1 In the southern ASEAN region, hotspot activities continued to be subdued by shower activities. There were some isolated hotspots detected in Kalimantan in end December 2015.
2.2 There was a gradual escalation of hotspot activities over the northern ASEAN region towards the end of December 2015. In particular, isolated hotspot activities were observed in Thailand and Cambodia. Localised smoke plumes were observed to emanate from some of these hotspots.
Fig. 2A: AQUA satellite image on 12 December 2015 shows isolated hotspots observed in Thailand.
Fig. 2B: AQUA satellite picture on 27 December 2015 shows scattered hotspots and localised smoke plumes detected in Cambodia.
Figure 2C: AQUA satellite image on 25 December 2015 hotspot activities in Sumatra subdued by shower activities in the area.
Fig. 2D: AQUA satellite image on 28 December 2015 shows widespread shower activities over the east coast of Peninsular Malaysia.
Fig. 2E: AQUA satellite picture on 31 December 2015 shows hotspot activities in Kalimantan subdued by scattered shower activities.
2.3 The hotspot charts for December 2015 for
- Cambodia, Myanmar, Thailand, Lao PDR and Vietnam;
- Sumatra, Borneo and Peninsular Malaysia;
Fig. 2F: Hotspot Counts in Cambodia, Lao PDR, Thailand, Vietnam, Myanmar for December 2015.
Fig 2G: Hotspot Counts in Sumatra, Borneo and Peninsular Malaysia for December 2015.
3. Status of El Niño/La Niña
3.1 The El Niño in the tropical Pacific Ocean is at mature levels in December 2015, with the sea-surface temperatures similar to the 1982-83 and 1997-98 strong El Niño events.
3.2 The consensus forecast based on assessments from international climate models and expert opinion suggests that the strong El Niño conditions to continue through the first quarter of 2016, and is expected to gradually weaken in the next few months, and is likely to return to Neutral conditions by around mid-2016.
3.3 The region is currently in the Northeast Monsoon season (late Nov – Mar),and the the impact of El Niño is usually less pronounced as compared to the Southwest Monsoon season (Jun – Sep). Typically, El Niño will bring drier than average rainfall conditions over Southeast Asia region, especially for the southern parts of the ASEAN region during June to October. More locally-specific impact differs from place to place and for different seasons.