Review of Regional Weather and Smoke Haze for Jan 2015

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1.   Review of Regional Weather Conditions in January 2015

1.1    Northeast Monsoon conditions prevailed in January 2015. In the northern ASEAN region, dry weather conditions continued to affect the Mekong Sub-region of Cambodia, Lao PDR, Myanmar, northern Thailand and Vietnam. In mid-January 2015, the monsoon rain-belt had moved south of the equator marking the onset of the dry phase of the Northeast Monsoon season in the southern ASEAN region. Generally cooler, drier and windy weather conditions were experienced in Sumatra, Peninsula Malaysia and Singapore while wet weather conditions were felt in Kalimantan, the Java islands as well as parts of Sabah and Sarawak in Malaysia. In the last week of January 2015, a monsoon surge brought heavy rains and caused floods in the states of Sabah and Sarawak in Malaysia.

1.2    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.

1.3    In January 2015, less than 75% of normal rainfall was received in most parts of northern ASEAN except in northern Thailand and southern parts of Vietnam, where more than 125% of normal rainfall was received. In most parts of the southern ASEAN region, less than 100% of normal rainfall was received. The regional rainfall distribution for January 2015 is shown in Fig. 1A.


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


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

2.1    In January 2015, the dry weather conditions led to an escalation of hotspot activities in the northern ASEAN region where scattered to widespread hotspots were observed on most days, in particular in Cambodia, central and northeastern Thailand and Lao PDR. Slight to moderate smoke haze was also observed on several occasions during the period.

2.2    In the southern ASEAN region, hotspot activities were mostly subdued by cooler and occasionally windy conditions. During brief periods of drier weather, sporadic hotspots were observed over central Sumatra and Peninsular Malaysia. Satellite images depicting some of the hotspot activities over the ASEAN region in February 2015 are shown in Figs. 2A to 2E.


Fig. 2A: NOAA-18 satellite picture on 12 January 2015 shows isolated hotspots over central Sumatra during period of drier weather.


Fig. 2B: NOAA-18 satellite picture on 13 January 2015 shows smoke plumes emanating from a cluster of hotspots near the Thailand-Cambodian border.

Fig. 2C: NOAA-18 satellite picture on 20 January 2015 shows widespread hotspot activities with moderate smoke haze observed in Cambodia.


Fig. 2D: TERRA satellite picture on 30 January 2015 shows localised hotspot activities over central Peninsular Malaysia.

Fig. 2E: NOAA-18 satellite picture on 30 January 2015 shows widespread hotspots with smoke plumes clustered near the Vietnam-Cambodian border.


2.3    The hotspot charts for January 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 January 2015.


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


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