Subseasonal Weather Outlook and Review

1.1    Northeast Monsoon conditions continued to prevail in February 2015. The northern ASEAN region is in the midst of the traditional dry season. Dry and warm weather conditions continued to prevail in the region interspersed with a few brief periods of shower activities. In the southern ASEAN region, a strengthening of the northeast monsoonal flow and the southward shift of the monsoon rain belt over the Java Sea areas brought dry weather conditions to Malaysia, Singapore and Sumatra but heavy rainfall over western Java, causing widespread flooding in Jakarta.

1.2    In February 2015, less than 50% of normal rainfall was received in the northern ASEAN region except in parts of northern Thailand and Lao PDR, where more than 125% of normal rainfall was received. In parts of the southern ASEAN region such as Peninsular Malaysia and Sumatra, less than 50 to 75% of normal rainfall was received. The regional rainfall distribution for February 2015 is shown in Fig. 1A.

2.1    In February 2015, hotspot activities continued to stay elevated under the prevailing drier weather, particularly over northern Thailand, Cambodia, Lao PDR and Myanmar. The northern provinces of Thailand were shrouded in slight to moderate haze for an extended period of time. Dense haze over a few provinces in northern Thailand such as Chiang Mai and Lampung experienced dense haze on a several days. Shower activities over the northern ASEAN region were brief and did not bring much relief to the haze situation.

2.2    In the southern ASEAN region, isolated hotspot activities emerged especially over central Sumatra and Peninsular Malaysia during periods of drier weather. Satellite images depicting some of the hotspot activities over the ASEAN region in February 2015 are shown in Figs. 2A to 2E.

1.1    Northeast Monsoon conditions continued to prevail in February 2015. The northern ASEAN region is in the midst of the traditional dry season. Dry and warm weather conditions continued to prevail in the region interspersed with a few brief periods of shower activities. In the southern ASEAN region, a strengthening of the northeast monsoonal flow and the southward shift of the monsoon rain belt over the Java Sea areas brought dry weather conditions to Malaysia, Singapore and Sumatra but heavy rainfall over western Java, causing widespread flooding in Jakarta.

1.2    In February 2015, less than 50% of normal rainfall was received in the northern ASEAN region except in parts of northern Thailand and Lao PDR, where more than 125% of normal rainfall was received. In parts of the southern ASEAN region such as Peninsular Malaysia and Sumatra, less than 50 to 75% of normal rainfall was received. The regional rainfall distribution for February 2015 is shown in Fig. 1A.

2.1    In February 2015, hotspot activities continued to stay elevated under the prevailing drier weather, particularly over northern Thailand, Cambodia, Lao PDR and Myanmar. The northern provinces of Thailand were shrouded in slight to moderate haze for an extended period of time. Dense haze over a few provinces in northern Thailand such as Chiang Mai and Lampung experienced dense haze on a several days. Shower activities over the northern ASEAN region were brief and did not bring much relief to the haze situation.

2.2    In the southern ASEAN region, isolated hotspot activities emerged especially over central Sumatra and Peninsular Malaysia during periods of drier weather. Satellite images depicting some of the hotspot activities over the ASEAN region in February 2015 are shown in Figs. 2A to 2E.