Category Archives: Regional Weather Outlook for Year 2020

August 8, 2020

Subseasonal Weather Outlook (10 – 23 August 2020)

Issued 8 August 2020

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

During the fortnight (10 Aug – 23 Aug), wetter conditions are expected over southern Southeast Asia particularly over the near-equatorial region as highlighted in the rainfall map.

Warmer conditions are expected during the fortnight over the southern and western parts of Southeast Asia.

A Madden-Julian Oscillation (MJO) signal developed over the Indian Ocean in the past fortnight, propagated eastwards and is now in the western Maritime Continent. Most models predict the MJO to continue propagating eastwards but may weaken in the first week.

The outlook is assessed for the region in general, where conditions are relative to the average conditions for the corresponding time of year. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.

July 27, 2020

Subseasonal Weather Outlook (27 July – 9 August 2020)

Issued 27 July 2020
First forecast week: 27 Jul – 2 Aug
Second forecast week: 3 Aug – 9 Aug

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

In the first forecast week (27 Jul – 2 Aug), wetter conditions are expected over much of the equatorial region, as well as southern and eastern coastal regions of Mainland Southeast Asia and the Philippines.

In the second forecast week (3 Aug – 9 Aug), wetter conditions are expected over eastern Southeast Asia and over the southern and eastern regions of Mainland Southeast Asia as highlighted in the rainfall map.

Drier conditions are expected over southern parts of Southeast Asia (southern Sumatra and Java). In the second week, drier conditions are also expected to develop over the rest of Sumatra and the region covering Peninsular Malaysia and western Borneo.

Warmer conditions are expected over northern Southeast Asia, particularly in the first forecast week. In the second week, warmer conditions are expected to develop over the western equatorial region, in line with the drier conditions.

While there are some signs of a Madden-Julian Oscillation (MJO) signal in the western Indian Ocean, the models are inconsistent in their predictions for the signal to continue during the forecast period.

The outlook is assessed for the region in general, where conditions are relative to the average conditions for the corresponding time of year. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.

July 13, 2020

Subseasonal Weather Outlook (16 – 31 July 2020)

Issued 13 July 2020
Valid for weeks 3 and 4: 16 – 31 July 2020

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

In the second fortnight of July 2020, wetter conditions are expected over much of the equatorial region of Southeast Asia. While the likelihood of these wetter conditions is similar for both weeks in the central and eastern equatorial region (Borneo, eastern Indonesia), there is some difference in the likelihood in the western equatorial region. In Week 3, wetter conditions are more likely for Sumatra and the southern Malay Peninsula, while in Week 4, wetter conditions are more likely for southern Thailand and southern Myanmar.

For northern Southeast Asia, drier conditions are expected over much of this region in Week 3, and becoming confined to western Myanmar in Week 4. During Week 3, the largest dry anomalies are expected over Myanmar, Lao PDR, and the northern Philippines.

Warmer conditions are expected over northern Southeast Asia, particularly in Week 3.

June 29, 2020

Subseasonal Weather Outlook (1 – 15 July 2020)

Issued 29 June 2020
Valid for weeks 1 and 2: 1 – 15 July 2020

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

In the first fortnight of July 2020, wetter conditions are expected over the equatorial regions of Southeast Asia, whereas drier conditions are expected over the northern and central parts of the Philippines.

In the first week of July, wetter conditions are expected over the southern parts of Mainland Southeast Asia.

Warmer conditions are expected over the northern and central parts of the Philippines, and the southern parts of the Maritime Continent for the first fortnight of July. For Mainland Southeast Asia, there is a higher likelihood of warmer conditions in the first week of July.

No discernible Madden-Julian Oscillation (MJO) signal is observed and there is no consistent signal in the models’ predictions for an MJO to develop in the forecast period.

June 15, 2020

Subseasonal Weather Outlook (16 – 30 June 2020)

Issued 15 June 2020
Valid for weeks 3 and 4: 16 – 30 June 2020

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

Wetter conditions are expected over most parts of the equatorial Maritime Continent in the second fortnight of June 2020.

Over northern Southeast Asia, drier conditions are expected in the second fortnight of June except for some coastal parts of Myanmar where wetter conditions are expected in Week 3.

Warmer conditions are expected over most parts of northern Southeast Asia, especially in Week 4. A higher likelihood of warmer conditions is also expected around the southeastern part of the Maritime Continent.

A Madden-Julian Oscillation (MJO) is currently present over the Indian Ocean. During the forecast period, most models predict the MJO to slow down as it enters the Maritime Continent. If the MJO continues to propagate, this would increase the likelihood of wetter conditions in the Maritime Continent.

May 28, 2020

Subseasonal Weather Outlook (1 – 15 June 2020)

Issued 28 May 2020
Valid for weeks 1 and 2: 1 – 15 June 2020

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

Wetter conditions are expected over most parts of the Maritime Continent in the first fortnight of June 2020. However, the wetter conditions may ease in the western Maritime Continent in Week 2.

Over Mainland Southeast Asia, particularly over parts of Myanmar and Lao PDR, drier conditions are expected in the first week of June. Drier conditions are also expected over northern and central parts of the Philippines over the first two weeks in June. The drier conditions are associated with weaker-than-normal Southwest Monsoon winds during the fortnight.

Warmer conditions are expected over most parts of Mainland Southeast Asia and northern and central Philippines, especially in Week 1. Over the Maritime Continent, a higher likelihood of warmer conditions is expected around the Java region.

A weak Madden-Julian Oscillation (MJO) is currently present over the Western Pacific. A number of models predict the MJO to continue propagating to the Western Hemisphere and Africa in the first week of June 2020, and possibly as far as the Indian Ocean in the week after.

May 15, 2020

Subseasonal Weather Outlook (16 – 31 May 2020)

Issued 15 May 2020
Valid for weeks 3 and 4: 16 – 31 May 2020

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

For the second fortnight of May 2020, drier conditions are expected over western Mainland Southeast Asia (parts of Myanmar and Thailand), easing over Thailand and southern Myanmar in Week 4.

For most of the southern parts of Southeast Asia, there is an increased chance of wetter conditions, particularly in Week 3.

Warmer conditions are expected over most of Mainland Southeast Asia. Much of the Maritime Continent also has an increased chance of warmer conditions, except for parts of Peninsular Malaysia, Borneo and northern Philippines.

There was no clear Madden-Julian Oscillation (MJO) signal in the second week of May. While models predict an MJO to emerge over the Indian Ocean in Week 3, most models suggest the signal will be short-lived.

April 29, 2020

Subseasonal Weather Outlook (1 – 15 May 2020)

Issued 29 April 2020
Valid for weeks 1 and 2: 1 – 15 May 2020

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

For the first fortnight of May 2020, drier conditions are expected to persist over most of northern Southeast Asia. However, for Myanmar, drier conditions are expected only in Week 2.

There is an increased chance of wetter conditions over the western Maritime Continent and southern parts of the eastern Maritime Continent associated with the Madden-Julian Oscillation (MJO) activity. The wetter conditions in the western Maritime Continent are expected to ease by Week 2.

For most of Southeast Asia, warmer conditions are expected throughout the first two weeks of May, with the warmest anomalies over parts of Cambodia, Laos and Viet Nam. Colder conditions are likely over northern and western Myanmar in Week 1.

An MJO is currently present over the eastern Indian Ocean. Some models predict the MJO to decay in Week 1 as it enters the Maritime Continent, while other models indicate the MJO may continue propagating through the region. If the MJO continues to propagate, this would increase the probability of wetter conditions in the eastern Maritime Continent.

The outlook is assessed for the region in general, where conditions are relative to the average conditions for the corresponding time of year. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.

April 14, 2020

Subseasonal Weather Outlook (16 – 30 April 2020)

Issued 14 April 2020
Valid for weeks 3 and 4: 16 – 30 April 2020

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

For the second fortnight of April 2020, drier conditions are expected to persist over Thailand, Cambodia, southern parts of Laos, southern parts of Viet Nam, southern parts of Myanmar, and most parts of the Philippines. Drier conditions are also forecasted to persist over northern Borneo, although these conditions may ease in Week 4 tied to the Madden-Julian Oscillation (MJO) activity.

There is an increased chance of wetter conditions over western parts of the Maritime Continent in Week 4 (northern Sumatra, Peninsular Malaysia, and eastern Borneo), associated with the same MJO signal.

For temperature in Week 3, warmer conditions are expected over most of Southeast Asia, apart from northern Myanmar and northern Viet Nam. These warmer conditions are expected to persist in Week 4, although the warmer conditions may ease in the equatorial part of the region.

An MJO is currently present over Africa and is expected to propagate eastward through the Indian Ocean during Week 3 and Week 4. However, a few models forecast the signal to weaken towards the end of April.

The outlook is assessed for the region in general. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.

March 30, 2020

Subseasonal Weather Outlook (1 – 15 April 2020)

Issued 30 March 2020
Valid for weeks 1 and 2: 1 – 15 April 2020

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

For the first fortnight of April 2020, drier conditions are expected to persist over northern Sumatra, Peninsular Malaysia, southern parts of Mainland Southeast Asia, northern Borneo and most parts of the Philippines.

There is an increased chance of wetter conditions over some parts of the southeastern Maritime Continent in Week 1. For some parts of the southern Maritime Continent (Java), wetter conditions could redevelop in Week 2.

For temperature, warmer conditions are expected over most of Southeast Asia for the second fortnight of April 2020. Models predict a high chance of way-above average temperatures (exceeding 90%-tile) for some parts of Myanmar, especially in Week 1.

An Madden-Julian Oscillation (MJO) is currently present over the Indian Ocean and is expected to propagate eastward towards the Maritime Continent by Week 1. There is uncertainty across different models whether the MJO will continue to propagate to the western Pacific Ocean beyond Week 1.

The outlook is assessed for the region in general. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.