Review of Regional Weather and Smoke Haze for Mar 2015 |

Review of Regional Weather and Smoke Haze for Mar 2015

1. Review of Regional Weather Conditions in March 2015

1.1 In the last week of March 2015, weak to moderate Northeast Monsoon conditions gave way to Inter-Monsoon conditions, and prevailing winds gradually weakened to become light and variable. The traditional dry season in the northern ASEAN region continued to prevail in the first half of the month, with drier weather conditions experienced mostly over northern Thailand and Myanmar. By late march 2015, a return of showers activities brought some respite to the dry weather conditions experienced in the past few months in the near-equatorial and northern ASEAN regions.

1.2 In March 2015, less than 50% of normal rainfall was received in most parts of the northern ASEAN region while in parts of central Thailand, Lao PDR and Vietnam received more than 125% of normal rainfall. In the southern ASEAN region, below normal rainfall was recorded over Peninsular Malaysia, Sabah, Sarawak and Kalimantan. The regional rainfall distribution for March 2015 is shown in Fig. 1A.

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

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

2.1 In March 2015, hotspot activities over northern Thailand, Myanmar and Cambodia remained elevated under the prevailing dry weather conditions. Parts of Myanmar and the northern provinces of Thailand were shrouded in occasional moderate haze for an extended period of time. In particular, elevated levels of PM10 were reported in several provinces in northern Thailand, namely- Chiang Mai, Maehongsorn and Lampung. The haze situation in northern Thailand and Myanmar improved with an increase in shower activities in late March 2015.

2.2 In the southern ASEAN region, hotspot activities were generally subdued in most parts of March 2015. During brief periods of drier weather, isolated hotspots with localised smoke haze were observed in central Sumatra. Satellite images depicting some of the hotspot activities over the ASEAN region in March 2015 are shown in Figs. 2A to 2E.

Fig. 2A: NOAA-18 satellite picture on 13 March 2015 shows widespread hotspots and dense smoke haze over Myanmar.

Fig. 2B: NOAA-18 satellite picture on 13 March 2015 shows isolated hotspot with localised smoke haze over central Sumatra.

Fig. 2C: NOAA-18 satellite picture on 15 March 2015 shows scattered hotspot and smoke haze near the Myanmar-northern-Thailand borders.

Fig. 2D: NOAA-18 satellite picture on 15 March 2015 shows that dense smoke haze continues to accumulate over different parts of Myanmar under the prevailing dry weather conditions.