Review of Regional Weather and Smoke Haze for Apr 2015

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1.   Review of Regional Weather Conditions in April 2015

1.1    Inter-Monsoon conditions prevailed over the ASEAN region in April 2015. The gradual northward migration of the monsoon trough brought an increase of shower activities over most parts of ASEAN region, especially towards late-April.

1.2    In April 2015, less than 50% of normal rainfall was received in most parts of northern ASEAN region except northern Thailand and Luzon Island in the Philippines. In the southern ASEAN region, near-normal rainfall was received across most parts. Less than 75% of normal rainfall was received mainly over southern Peninsular Malaysia, northern Sumatra and northern Borneo. The regional rainfall distribution for April 2015 is shown in Fig. 1A.


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


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

2.1    In April 2015, there was a gradual reduction in hotspot activities over the northern ASEAN region due to increased shower activities in the region. Localised smoke haze and hotspot activities were observed in early-April especially in the northern parts of Lao PDR and Vietnam, as well as in areas around the border between Thailand and Myanmar. Towards the later part of April 2015, persistent shower activities further subdued hotspot activities in the northern ASEAN region

2.2    In the southern ASEAN region, hotspot activities were generally subdued by widespread shower activities that affected the region. Satellite images depicting some of the hotspot activities over the ASEAN region in April 2015 are shown in Figs. 2A to 2E.


Fig. 2A: NOAA-18 satellite image on 3 April 2015 showing isolated hotspots in the northern areas between Lao PDR and Vietnam.


Fig. 2B: NOAA-18 satellite image on 3 April 2015 shows showers affecting most parts of Kalimantan. Hotspot activities were subdued by the widespread showers.

Fig. 2C: NOAA-18 satellite image on 9 April 2015 shows the emergence of localised hotspot activities in Cambodia.


Fig. 2D: NOAA-18 satellite image on 18 April 2015 shows moderate to dense smoke haze emanating from hotspots located over northern parts of Thailand, Lao PDR and Vietnam.

Fig. 2E: NOAA-18 satellite image on 27 April 2015 shows most parts of Myanmar affected by showers which helped to subdue the hotspot activities there.


2.3    The hotspot charts for April 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 April 2015.


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


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