Category Archives: ASEAN Climate Outlook Forum

Fourteenth Session of the ASEAN Climate Outlook Forum (ASEANCOF-14)

21st May 2020, Online Correspondence
 

Consensus Bulletin for June-July-August (JJA) 2020 Season

The ASEAN Climate Outlook Forum (ASEANCOF) is an avenue to collaboratively develop consensus-based seasonal climate outlooks and related information on a regional scale.

The forum outlook and its activities contribute significantly to one of the key roles of the ASEAN Specialised Meteorological Centre (ASMC), which is to conduct climate and seasonal prediction for the ASEAN region through pooling the expertise of ASEAN National Meteorological Services.

The fourteenth ASEANCOF (ASEANCOF-14) was organised by Meteorological Service Singapore as host of the ASEAN Specialised Meteorological Centre. Representatives from National Meteorological and Hydrological Services (NMHSs) of ASEAN Member States created a consensus forecast for the summer monsoon 2020 in the ASEAN region. The consensus for June-July-August (JJA) 2020 outlooks was achieved through online correspondence, including questionnaires and online discussions regarding the current conditions and predictions for the Southeast Asia region. In particular, the forum considered the possible influence of the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) on the climate system over Southeast Asia.

Conditions and Outlook

Recent analysis of sea surface temperature (SST) anomalies over the equatorial Pacific indicate near average SSTs and ENSO neutral conditions are present. The international climate outlooks predict ENSO neutral conditions are likely to continue during JJA 2020, although there is potential that La Niña conditions may begin to develop towards the end of the period or later in the year. The previous positive Indian Ocean Dipole (IOD) weakened in January 2020 and the current IOD state is neutral. Some models predict a negative IOD event to develop during JJA, but with relatively high uncertainty at this time of year.

The consensus from ASEANCOF is an increased chance of a negative IOD event to develop during JJA while ENSO conditions are most likely to remain neutral during JJA. The Southwest (SW) Monsoon is expected to be weaker than normal, based on model predictions. However, local rainfall for some regions will depend on tropical cyclone activity, which is uncertain. For most countries, the onset of the SW monsoon is expected to be near-normal. However, the SW monsoon related rainfall may arrive later than normal for a few countries (Thailand and Viet Nam). Overall, the tropical cyclone frequency is expected to be near normal for JJA 2020.

Taking into consideration the national level forecasts, the present state of the climate, and the forecasts available from GPCs and other global centres, the forum agreed on the following consensus-based outlook for JJA 2020 for the Southeast Asia region:

RAINFALL

For the upcoming Northern Hemisphere summer season (June-July-August), normal- to above-normal rainfall is expected over much of the equatorial region (Brunei, Malaysia, Singapore, and northern parts of Indonesia) as well as northern Viet Nam and coastal central Viet Nam. Normal- to below-normal rainfall is expected over southern Myanmar, southern and northeastern Thailand, northern Philippines, parts of Lao PDR, and southeastern Indonesia. Elsewhere, normal or climatological probabilities are forecasted.

TEMPERATURE

Above-normal temperature is expected over most of Southeast Asia, although the probability of above-normal temperature is lower over Viet Nam and parts of Indonesia, and northern Philippines.

Refer to Annex A for reference on what is meant by “above, near, or below normal” in the outlook. For more information on the Northern Hemisphere Summer Monsoon outlook and further updates on the national scale, the relevant NMHSs should be consulted (see Annex B).
 

Consensus Maps for JJA 2020

The following maps provide the probabilistic outlooks for JJA 2020 season in terms of tercile categories of “Above Normal” (AN: upper tercile), “Near Normal (NN: middle tercile) and “Below Normal” (BN: lower tercile).

PROBABILISTIC RAINFALL OUTLOOK

PROBABILISTIC TEMPERATURE OUTLOOK

Meeting Documents

ASEANCOF-14 Outlook Bulletin
 

Acknowledgements

The Forum would like to convey its appreciation to the National Meteorological Services of the ASEAN Member States for sharing their national-level forecasts, the Global Producing Centres and other participating international climate modelling centres for their products and expertise made available for this Climate Outlook Forum.

Thirteenth Session of the ASEAN Climate Outlook Forum (ASEANCOF-13)

November 2019, Thai Meteorological Department in collaboration with the ASEAN Specialised Meteorological Centre (ASMC)

Consensus Bulletin for December-January-February (DJF) 2019-2020 Season

The ASEAN Climate Outlook Forum (ASEANCOF) is an avenue to collaboratively develop consensus-based seasonal climate outlooks and related information on a regional scale for Southeast Asia.

The forum outlook and its activities contribute significantly to one of the key roles of the ASEAN Specialised Meteorological Centre (ASMC), which is to conduct climate and seasonal prediction for ASEAN region through pooling the expertise of ASEAN National Meteorological Services.

The Thirteenth ASEANCOF (ASEANCOF-13) was organised by the Thai Meteorological Department in collaboration with Meteorological Service Singapore as host of the ASEAN Specialised Meteorological Centre.

Representatives from National Meteorological and Hydrological Services (NMHSs) of ASEAN Member States created a consensus forecast for the boreal winter 2019-2020 in the ASEAN region. The consensus for December-January-February (DJF) 2019-2020 outlooks was achieved through the Thirteenth ASEAN Climate Outlook Forum and Training in Bangkok, Thailand from 18 to 21 November 2019. The consensus was made based on presentations and discussions on current conditions and predictions for the Southeast Asia region. In particular, the forum took into account the significant influence of the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) on the climate over Southeast Asia.

Conditions and Outlook

Recent analysis of sea surface temperature (SST) anomalies over the equatorial Pacific indicate slightly above average SSTs across most of the Pacific Ocean. The ENSO neutral conditions have been present since July 2019. The international climate outlooks predict ENSO neutral conditions are likely to continue during DJF 2019-2020. The present positive Indian Ocean Dipole (IOD) is expected to weaken in DJF 2019-2020. The Northeast monsoon for the southern half of the region is expected to be delayed due to the strong positive IOD at the start of the season.

Taking into consideration the national level forecasts, the present state of the climate, and the forecasts available from GPCs and other global centres, the forum agreed on the following consensus-based outlook for DJF 2019-2020 for the Southeast Asia region:

RAINFALL

For the upcoming Northern Hemisphere winter season (December-January-February), near-normal conditions are expected over most parts of Mainland Southeast Asia, and parts of the equatorial region. However, there is a slightly enhanced probability of wetter than normal conditions over northern Vietnam, the eastern part of Malaysia, the eastern part of Celebes, Moluccas and northern part of Papua. There is a slightly increased probability of drier than normal conditions over the southern part of Myanmar, parts of Thailand (the northern, central, eastern and south-eastern of region), Philippines, northern and southern Sumatra, Java, the western part of Celebes, Bali, Nusa Tenggara, the southern part of Borneo and the southern part of Papua.

TEMPERATURE

Above normal temperatures are expected for most of Southeast Asia, apart from northern Myanmar, southern Thailand and northern Sumatra, where near normal temperatures are expected. For the regions with expected above normal temperature, the highest probability is over northern Vietnam, Lao PDR, Cambodia, northern Thailand and southern Myanmar.

Refer to Annex A for reference on what is meant by “above, near, or below normal” in the outlook. For more information on the Northern Hemisphere Summer Monsoon outlook and further updates on the national scale, the relevant NMHSs should be consulted (see Annex B).

Consensus Maps for DJF 2019-2020

The following maps provide the probabilistic outlooks for DJF 2019-2020 season in terms of tercile categories of “Above Normal” (AN: upper tercile), “Near Normal (NN: middle tercile) and “Below Normal” (BN: lower tercile).

PROBABILISTIC RAINFALL OUTLOOK

PROBABILISTIC TEMPERATURE OUTLOOK

Meeting Documents

ASEANCOF-13 Outlook Bulletin

Acknowledgements

The Forum would like to convey its appreciation to the National Meteorological Services of the ASEAN Member States for sharing their national-level forecasts, the Global Producing Centres and other participating international climate modelling centres for their products and expertise made available for this Climate Outlook Forum. The Forum would also like to thank the ASEAN Secretariat, the WMO Secretariat, and the local organising committee from TMD for the administrative and funding support provided to the meeting.

Twelfth Session of the ASEAN Climate Outlook Forum (ASEANCOF-12)

May 2019, Thai Meteorological Department in collaboration with ASEAN Specialised Meteorological Centre (ASMC)

Consensus Bulletin for June-July-August (JJA) 2019 Season

The ASEAN Climate Outlook Forum (ASEANCOF) is an avenue to collaboratively develop consensus-based seasonal climate outlooks and related information on a regional scale.

The forum outlook and its activities contribute significantly to one of the key roles of the ASEAN Specialised Meteorological Centre (ASMC), which is to conduct climate and seasonal prediction for ASEAN region through pooling the expertise of ASEAN National Meteorological Services.

The Twelfth ASEANCOF (ASEANCOF-12) was organised by the Thai Meteorological Department in collaboration with Meteorological Service Singapore as host of the ASEAN Specialised Meteorological Centre. Representatives from National Meteorological and Hydrological Services (NMHSs) of ASEAN Member States created a consensus forecast for the Summer Monsoon 2019 in the ASEAN region. The consensus for June-July-August (JJA) 2019 outlooks was achieved through online correspondence. The consensus was made based on completed questionnaires regarding current conditions and predictions for the Southeast Asia region as well as an online discussion. In particular, the forum took into account the significant influence of the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) on the climate system over Southeast Asia.

Conditions and Outlook

Recent analysis of Sea Surface Temperature (SST) anomalies over the Equatorial Pacific indicate above average SSTs across most of the Pacific Ocean. Borderline El Niño conditions have been present since SON 2018. The international climate outlooks predict El Niño conditions are likely to continue during JJA 2019. The present neutral Indian Ocean Dipole (IOD) is expected to develop into a positive IOD in JJA 2019 and the later part of the year.

The Summer Monsoon is predicted to be normal throughout Southeast Asia. As such, near normal occurrence of tropical cyclones is expected over the Bay of Bengal. Due to the prediction of a normal Summer Monsoon along with El Niño conditions, the occurrence of tropical cyclones in the Philippines is expected to be below normal.

Taking into consideration the national level forecasts, the present state of the climate, and the forecasts available from GPCs and other global centres, the forum agreed on the following consensus-based outlook for JJA 2019 for the Southeast Asia region:

RAINFALL

For the upcoming Northern Hemisphere Summer Monsoon season (June-July-August), below normal conditions are expected over most parts of the Southeast Asia. However, there is a slightly enhanced probability of wetter than normal conditions over western and southern Myanmar and parts of Sumatra, Northern Celebes, Moluccas, and Papua islands of Indonesia.

TEMPERATURE

Above normal temperatures are expected over much of central and eastern Southeast Asia, including parts of Peninsular Malaysia, Singapore, central and western Indonesia. Normal to above normal temperature are expected elsewhere, including Philippines, Moluccas and Papua islands of Indonesia.

Refer to Annex A for reference on what is meant by “above, near, or below normal” in the outlook. For more information on the Northern Hemisphere Summer Monsoon outlook and further updates on the national scale, the relevant NMHSs should be consulted (see Annex B).

Consensus Maps for JJA 2019

The following maps provide the probabilistic outlooks for JJA 2019 season in terms of tercile categories of “Above Normal” (AN: upper tercile), “Near Normal (NN: middle tercile) and “Below Normal” (BN: lower tercile).

PROBABILISTIC RAINFALL OUTLOOK

PROBABILISTIC TEMPERATURE OUTLOOK

Meeting Documents

ASEANCOF-12 Outlook Bulletin

Acknowledgements

The Forum would like to convey its appreciation to the National Meteorological Services of the ASEAN Member States for sharing their national-level forecasts, the Global Producing Centres and other participating international climate modelling centres for their products and expertise made available for this Climate Outlook Forum.

11th ASEAN COF (29 Oct – 1 Nov 2018, Malaysia)

The Eleventh ASEAN Climate Outlook Forum (ASEANCOF-11) was held in Kuala Lumpur, Malaysia from 29 October – 01 November 2018. This forum was organised by the Malaysian Meteorological Department in collaboration with the ASEAN Specialised Meteorological Centre (ASMC). The ASEANCOF was started in 2013, as part of the World Meteorological Organisation/Climate Information and Prediction Services (WMO/CLIPS) project for Regional Climate Outlook Forum (RCOFs) in cooperation with National Meteorological and Hydrological Services (NMHSs). It is a platform for regional NMHSs and international partners such as the WMO Global Producing Centres (GPCs) to collaboratively develop a consensus-based seasonal climate outlook and related information on a regional scale. It also provides an avenue for NMHSs to share best practices and get updated on the latest scientific advances in seasonal predictions. The ASEANCOF-11 event was co-funded by the ASEAN Science Technology and Innovation Fund (ASTIF), World Meteorological Organization (WMO) through its partners, and Malaysian Meteorological Department.

The forum’s outlook and activities contribute significantly to one of the key roles of the ASMC, which is to conduct climate and seasonal prediction for ASEAN region through pooling the expertise of ASEAN NMHSs. The Forum also supports the activities of the Southeast Asia Regional Climate Centre Network (SEA RCC-Network) – which entered the demonstration phase on 7 November 2017 – by providing the consensus outlook as well as the platform to discuss issues on provision of climate services in the Southeast Asia region.

The forum was attended by representatives from the region’s NMHSs, i.e. Brunei, Indonesia, Lao, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam who presented on their national rainfall and temperature outlook for the upcoming December 2018 – February 2019 (DJF 2018-19) boreal winter monsoon season. The NMHSs were joined by experts from the Bureau of Meteorology, Australia (BoM), China Meteorological Administration (CMA), European Centre for Medium-range Weather Forecast (ECMWF), Japan Meteorological Agency (JMA), UK MetOffice (UKMO), and the WMO Lead Center for Long Range Forecast Multi-Model Ensemble (WMO LC-LRFMME), who presented on the regional outlook from their respective models. To provide scientific basis for the outlook of DJF 2018-19, the Forum also assessed the various global and regional climatic factors that influence the DJF season in the area. In particular, the Forum took into account the influence on the climate over Southeast Asia from the El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), tropical cyclones, and the monsoon circulation patterns.

Three regional end-user agencies from the water resources management and agricultural sectors were also invited, namely, the ASEAN Hydroinformatics Data Centre (AHC), the International Rice Research Institute (IRRI), and the Mekong River Commission (MRC). The agencies shared on their activities that serve the respective communities and, in line with this year’s meeting theme, they shared on their requirements for seasonal predictions and monitoring of extreme weather and climate.

Conditions and Outlook

The ENSO was in warm-neutral conditions in late October 2018. There is a 70% chance for an El Niño event to develop in the season DJF 2018-19 but its intensity is unlikely to be strong, and more likely to be weak than moderate. The Indian Ocean Dipole (IOD) index was also slightly positive (warmer western Indian ocean SST, and cooler eastern Indian Ocean SST). But the IOD is predicted to be neutral in DJF 2018-19.

For monsoon activity, due to warmer conditions predicted over East Asia in the DJF 2018-19 season, a weaker high pressure system is generally expected and consequently may result in weaker northeast monsoon winds. This coupled with potential changes in the Walker Circulation due to El Niño, convective rainfall activity is expected to be relatively suppressed in general for the region in DJF 2018-2019. Typically, during El Niño events, tropical cyclone activity in the Southwest Pacific tends to be less active (less frequent). However, as the El Niño event is not expected to be a strong one, and models are not showing significantly reduced tropical cyclone activity in the DJF 2018-19; a near-normal situation is more likely.

Taking into consideration the national level forecasts, the present state of the climate, and the forecasts available from GPCs and other global centres, the forum agreed on the following consensus-based outlook for DJF 2018-19 for the Southeast Asia region:

RAINFALL

For the upcoming boreal winter monsoon season (DJF 2018-19), below-normal conditions are favoured over parts of the Philippines, southern Vietnam, northern Laos, central and southern Myanmar, southern Thailand, and northern Borneo. Elsewhere near- to above-normal rainfall conditions are favoured, with relatively less confident probabilities.

TEMPERATURE

Above-normal temperatures are favoured over much of the Southeast Asia region for the upcoming boreal winter monsoon season (DJF 2018-19). Near-normal to above-normal temperatures are favoured over southern Vietnam, Brunei, and northern-central Myanmar.

Refer to Annex A for reference on what is meant by “above, near, or below normal” in the outlook. For more information on the Northern Hemisphere winter monsoon outlook and further updates on the national scale, the relevant NMHSs should be consulted (see Annex B).

Consensus Maps for DJF 2018-2019

The following maps provide the probabilistic outlooks for DJF 2018-19 season in terms of tercile categories of “Above-Normal” (AN: upper tercile), “Near-Normal (NN: middle tercile) and “Below-Normal” (BN: lower tercile).

PROBABILISTIC RAINFALL OUTLOOK

PROBABILISTIC TEMPERATURE OUTLOOK

Meeting Documents

ASEANCOF-12 Outlook Bulletin

Acknowledgement

The Forum would like to convey its appreciation to the National Meteorological Services of the ASEAN Member States for sharing their national-level forecasts, the Global Producing Centres and other participating international climate modelling centres for their products and expertise made available for this Climate Outlook Forum. The Forum would also like to thank the ASEAN Secretariat, the WMO Secretariat, and the local organising committee from MMD for the administrative and funding support provided to the meeting.

10th ASEAN COF (May 2018, Online Correspondence)

The ASEAN Climate Outlook Forum (ASEANCOF) is an avenue to collaboratively develop consensus-based seasonal climate outlooks and related information on a regional scale.

The forum outlook and its activities contribute significantly to one of the key roles of the ASEAN Specialised Meteorological Centre (ASMC), which is to conduct climate and seasonal prediction for ASEAN region through pooling the expertise of ASEAN National Meteorological Services.

The Tenth ASEANCOF (ASEANCOF-10) was organised by the Malaysian Meteorological Department in collaboration with the Meteorological Services Singapore as host of the ASEAN Specialised Meteorological Centre. Representatives from National Meteorological and Hydrological Services (NMHSs) of 10 ASEAN Member States created a consensus forecast for the summer monsoon 2018 in the ASEAN region. The consensus for June-July-August (JJA) 2018 outlooks was achieved through online correspondence. The consensus is made based on the completed questionnaires on current conditions and predictions for the Southeast Asia region. In particular, the forum took into account the significant influence of the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) on the climate over Southeast Asia.

Conditions and Outlook for JJA 2018

Recent analysis of sea surface temperature (SST) anomalies over the tropical Pacific indicate an ENSO neutral state. The warmer than average SSTs during first quarter of 2018 over eastern Pacific weakened in May.

The international climate outlooks show ENSO-neutral conditions are now present and likely to continue during JJA 2018. The present neutral Indian Ocean Dipole (IOD) is expected to continue towards the later part of the year.

The Southwest Monsoon is predicted to be generally normal throughout Southeast Asia. As such, the occurrence of five to seven tropical cyclones is expected in the Philippines. Likewise, near normal occurrence of tropical cyclones is also expected over the Bay of Bengal. Elsewhere, the occurrence of Squalls is favoured during this period.

Taking into consideration the national level forecasts, the present state of the climate, and the forecasts available from GPCs and other global centres, the forum agreed on the following consensus-based outlook for JJA 2018 for the Southeast Asia region.

RAINFALL

For the upcoming Northern Hemisphere summer monsoon season (June-July-August), normal conditions are expected over most parts of the Southeast Asia. However, there is a slightly enhanced probability of wetter than normal conditions over coastal Myanmar and central Philippines. Below to near normal rainfall is expected over western and central Borneo, Singapore, and central Indonesia.

TEMPERATURE

Above normal temperatures are expected over much of central and eastern Southeast Asia, including parts of Peninsular Malaysia, Singapore, northern Borneo, central and southern Philippines, and eastern Indonesia. Near normal temperature are expected elsewhere, including over Mainland Southeast Asia.

Refer to Annex A for reference on what is meant by “above, near, or below normal” in the outlook. For more information on the Northern Hemisphere summer monsoon outlook and further updates on the national scale, the relevant NMSs should be consulted (see Annex B).

Consensus Maps for JJA 2018

The following maps provide the probabilistic outlooks for JJA 2018 season in terms of tercile categories of “Above Normal” (AN: upper tercile), “Near Normal (NN: middle tercile) and “Below Normal” (BN: lower tercile).

PROBABILISTIC RAINFALL OUTLOOK

PROBABILISTIC TEMPERATURE OUTLOOK

Meeting Documents

ASEANCOF-10 Outlook Bulletin

Acknowledgement

The Forum would like to convey its appreciation to the National Meteorological Services of the ASEAN Member States for sharing their national-level forecasts, the Global Producing Centres and other participating international climate modelling centres for their products and expertise made available for this Climate Outlook Forum.

9th ASEAN COF (15-17 Nov 2017, Hanoi)

The Ninth ASEAN Climate Outlook Forum (ASEANCOF-9) was held in Hanoi, Vietnam from 15-17 November 2017. The Forum was organised by the National Hydro-Meteorological Service of Viet Nam (NHMS) in cooperation with the ASEAN Specialised Meteorological Centre (ASMC). The Environment and Climate Change Canada (ECCC) provided financial support for the Forum through its funded project: “Building Resilience to High-Impact Hydrometeorological Events through Strengthening Multi-Hazard Early Warning Systems in Small Island Developing States (SIDS) and Southeast Asia (SEA)”. The event was co-funded by the World Meteorological Organization (WMO) and NHMS Viet Nam.

The Forum was attended by representatives of the National Meteorological and Hydrological Services (NMHSs) of Indonesia, Lao, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam who discussed on the consensus outlook. They were joined by experts from the Bureau of Meteorology, Australia (BoM), European Centre for Medium-range Weather Forecast (ECMWF), International Research Institute for Climate and Society (IRI), Korea Meteorological Administration (KMA), and the WMO Lead Center for Long Range Forecast Multi-Model Ensemble (WMO LC-LRFMME). Seasonal climate outlooks from the Japan Meteorological Agency (JMA) and UK MetOffice (UKMO) was presented by ASMC on their behalves. The Forum also reviewed the present climate conditions in the Southeast Asia region, and discussed the various global and regional climatic factors that will influence the DJF season in the area. In particular, the Forum took into account the influence of the El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), as well as tropical cyclones and monsoon activities on the climate over Southeast Asia.

The ASEANCOF is an avenue to collaboratively develop a consensus-based seasonal climate outlook and related information on a regional scale. The Forum outlook and its activities contribute significantly to one of the key roles of the ASEAN Specialised Meteorological Centre (ASMC), which is to conduct climate and seasonal prediction for ASEAN region through pooling the expertise of ASEAN NMHSs. The Forum also supports the activities of the Southeast Asia Regional Climate Centre Network (SEA RCC-Network) – which entered the demonstration phase on 7 November 2017 – by providing the consensus outlook as well as the platform to discuss issues on provision of climate services in the Southeast Asia region.

          

Conditions and Outlook for DJF 2017-2018

Sea surface temperature (SST) over the tropical Pacific Ocean is currently cool (negative anomaly) with La Niña like or borderline conditions. Atmospheric indicators of ENSO conditions (e.g. the Southern Oscillation Index, SOI) are broadly within neutral at the moment.

However, models suggest the tropical Pacific Ocean will continue to cool. There is chance of a weak La Niña forming in late 2017 of at least 60%, around double the normal likelihood for La Niña. If it forms, the event is not expected to last beyond March 2018. While varying in local impacts, La Niña events are generally associated with wetter-than-average rainfall conditions over the ASEAN region, especially in the southern and eastern halves of the region.

The IOD index was recently slightly positive (warmer western Indian Ocean SST, and cooler eastern Indian Ocean SST) but is predicted to be neutral in DJF 2017-2018. The monsoon trough will be active in the south of Vietnam and over the Philippines for DJF 2017-2018. Thus more convective rainfall and tropical storms activities are expected there.

Taking into consideration the present status of the climate conditions affecting Southeast Asia, the forecasts available from the GPCs and other global centres, and the national-level assessment from the NMHSs, the Forum agreed on the following consensus-based outlook for the DJF 2017-2018 season for Southeast Asia.

RAINFALL

For the upcoming boreal winter monsoon season (Dec-Jan-Feb 2017-2018), above normal rainfall is favoured over the eastern Maritime Continent, southern Vietnam, and central and southern Thailand. Below normal rainfall is slightly favoured over western Borneo and northern Mainland Southeast Asia. Elsewhere near normal rainfall is favoured.

TEMPERATURE

Above normal temperatures are favoured over much of the Southeast Asia region for the upcoming boreal winter monsoon season (Dec-Jan-Feb 2017-2018), with the highest probabilities over the eastern Maritime Continent, northern Mainland Southeast Asia, and Sumatra. Below normal temperatures are favoured over northern Philippines and southern Vietnam.

Refer to Outlook Bulletin Annex A for reference on what is meant by “above, near, or below normal” in the outlook. For more information on the Northern Hemisphere winter monsoon outlook and further updates on the national scale, the relevant NMSs should be consulted (see Outlook Bulletin Annex B). The review for the JJA 2017 consensus outlook from ASEANCOF-8 is included in the Outlook Bulletin Annex C for reference.

Consensus Maps for DJF 2017-2018

The following maps provides the probabilistic outlooks for DJF 2017-2018 in terms of tercile categories of “Above Normal” (AN; upper tercile), “Near Normal” (NN; middle tercile), and “Below Normal” (BN; lower tercile).

PROBABILISTIC RAINFALL OUTLOOK

PROBABILISTIC TEMPERATURE OUTLOOK

Meeting Documents

ASEANCOF-9 Outlook Bulletin

8th ASEAN COF (May 2017, Online Correspondence)

Introduction

The ASEAN Climate Outlook Forum (ASEANCOF) is an avenue to collaboratively develop consensus-based seasonal climate outlooks and related information on a regional scale. The forum outlook and its activities contribute significantly to one of the key roles of the ASEAN Specialised Meteorological Centre (ASMC), which is to conduct climate and seasonal prediction for ASEAN region through pooling the expertise of ASEAN National Meteorological Services.

The Eighth ASEANCOF (ASEANCOF-8) was organized by Meteorological Services Singapore as host of the ASEAN Specialised Meteorological Centre. Representative from National Meteorological and Hydrological Services (NMHSs) of 10 ASEAN Member countries: Brunei, Cambodia, Indonesia, Lao PDR, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam created a consensus forecast for the summer monsoon 2017 in the ASEAN region. As with previous June-July-August (JJA) outlooks, the consensus was achieved through online correspondence. Each country completed a questionnaire on the current conditions and predictions for the Southeast Asia region. In particular, the forum took into account the significant influence of the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) on the climate over Southeast Asia.

Conditions & Outlook

Recent analysis of sea surface temperature (SST) anomalies over the tropical Pacific indicate an ENSO neutral state. The warmer than average SSTs in the eastern Pacific weakened slightly in May.

During JJA 2017, international climate outlooks show a near equal chance of conditions remaining neutral and a weak El Niño developing. An El Niño is indicated by warmer SST over central and eastern tropical Pacific, and often leads to drier conditions for Southeast Asia. Should an El Niño develop, the conditions are expected to be weak and have less impact on the Maritime Continent than previous El Niño events.

The Indian Ocean Dipole (IOD) is currently slightly positive, but still within the neutral state. While some international climate models predict a positive IOD for JJA, the skill of the models is low at this point.

The Southwest Monsoon is predicted to be near normal, but over the Western North Pacific monsoon surges may occur during the passage of tropical cyclones. For the Bay of Bengal, the number of TCs is predicted to be normal to above normal.

Taking into consideration the national level forecasts, the present state of the climate, and the forecasts available from GPCs and other global centers, the forum agreed on the following consensus-based outlook for JJA 2017 for the Southeast Asia region:

RAINFALL

For the upcoming Northern Hemisphere summer monsoon season (June-July-August), drier than normal conditions are expected over central and southern Southeast Asia, including southern Sumatra, southern Kalimantan, Java, Singapore and Sarawak. There is a slightly enhanced probability of wetter than normal conditions over coastal Myanmar, northern Thailand, northern Philippines, northern Papua, and northern Kalimantan. Near normal conditions are predicted for the rest of the region, including most of mainland Southeast Asia.

TEMPERATURE

Near normal or above normal temperatures are expected over much of Southeast Asia for the Northern Hemisphere summer monsoon season (June-July-August). Above normal temperature is expected over much of Indonesia, Singapore, Brunei, Sarawak, Thailand, and northern Myanmar.

Refer to Outlook Bulletin Annex A for reference on what is meant by “above, near, or below normal” in the outlook. For more information on the Northern Hemisphere winter monsoon outlook and further updates on the national scale, the relevant NMSs should be consulted (see Outlook Bulletin Annex B). The review for the DJF 2016 consensus outlook from ASEANCOF-7 is included in the Outlook Bulletin Annex C for reference.

Consensus Maps for JJA 2017

Probabilistic Rainfall Outlook

Probabilistic Temperature Outlook

Acknowledgements

The forum would like to thank the National Meteorological Services of the ASEAN Member countries for conveying their national-level forecasts, the Global Producing Centres and other participating international climate modelling centres for their products and expertise made available for this climate outlook forum.

7th ASEAN COF (14-18 Nov 2016, Manila)

The Seventh ASEAN Climate Outlook Forum (ASEANCOF-7) was organised by the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) in cooperation with ASEAN Specialized Meteorological Center, with funding support from the United States Agency for International Development (USAID) through the World Meteorological Organization (WMO). As with previous ASEANCOF meetings, representatives from National Meteorological and Hydrological Services (NMHSs) of all 8 ASEAN Member countries: Brunei, Indonesia, Lao, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam convened to create a consensus forecast of winter monsoon 2016-17 (DJF) in the ASEAN region. In addition, experts from the WMO Global Producing Centres (GPCs): Japan Meteorological Agency (JMA), Climate Prediction Center (CPC, NOAA), Bureau of Meteorology (BOM), APEC Climate Center (APCC), European Centre for Medium-range Weather Forecast (ECMWF), China Meteorological Administration (CMA), and WMO Lead Center for Long Range Forecast Multi-Model Ensemble (WMO LC-LRFMME) also shared their respective outlooks and guided the forum through building a consensus statement in the region.

The ASEANCOF is an avenue to collaboratively develop a consensus-based seasonal climate outlooks and related information on a regional scale. The forum outlook and its activities contribute significantly to one of the key roles of the ASEAN Specialised Meteorological Centre (ASMC), which is to conduct climate and seasonal prediction for ASEAN region through pooling the expertise of ASEAN National Meteorological Services. The consensus outlook for the December-January-February 2016-2017 season for the ASEAN region benefits from the guidance of the WMO GPC model outputs, as well as other global providers.  In particular, use is made of the multi-model ensemble forecasts from WMO LC-LRFMME as well as country-level forecasts developed by the participating national experts. The forum reviewed the present climate conditions in the Southeast Asia region, and discussed the various global and regional climatic factors that will influence the DJF season in the area. In particular, the forum took into account the significant influence of the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) on the climate over Southeast Asia.

Conditions and Outlook for DJF 2016-2017

Observed sea surface temperatures (SST) in the tropical Pacific remain cooler than average since July-August-September 2016 season indicating La Niña-like conditions. However, recent analyses of atmospheric conditions remain within the neutral range.

A number of climate models slightly favor weak and short-lived La Niña to persist in DJF 2016-17. La Niña is characterized by persistent cooler tropical Pacific SST anomalies, SSTA (-0.5°C or below) and stronger easterly winds over the tropical Pacific Ocean. While varying in local impacts, La Niña events are generally associated with wetter-than-average rainfall conditions over the ASEAN region, especially in the southern and eastern half of the region.

The IOD is predicted to be in a weakly negative to neutral state in DJF 2016-17. Negative IOD is generally associated with warmer than usual SSTA in tropical eastern Indian Ocean in contrast with cooler than normal SSTA in tropical western Indian Ocean. While negative IOD can potentially reinforce the impacts of La Niña, climate models generally do not predict persistence in negative IOD values.

It is also predicted that the frequency of tropical cyclones in the Western North Pacific Region will be above average in DJF 2016-17. Meanwhile, tropical cyclone frequency in the Bay of Bengal will likely remain near average.

Finally, a number of climate models show that the northeast Monsoon is likely stronger than average. It is, however, noteworthy that the effects of this predicted strength in the monsoon could potentially be confined to the northern portions of the region.

Taking into consideration the national-level forecasts, the present status of the climate conditions affecting Southeast Asia, and the forecasts available from the GPCs and other global centres, the forum agreed on the following consensus-based outlook for the DJF 2016-17 season for the Southeast Asia region:

RAINFALL

For the upcoming Northern Hemisphere winter monsoon season (Dec-Jan-Feb 2016-17), there is a slightly enhanced probability of below normal rainfall over northern mainland Southeast Asia, near normal to above normal rainfall over central and western Southeast Asia, which includes most parts of Thailand, Cambodia, southern Myanmar, and western portion of the Philippines. Slightly enhanced probabilities of above normal rainfall are predicted over the rest of the Philippines and eastern Maritime Continent.

TEMPERATURE

Slightly above to above normal air temperatures are very likely to occur over much of Southeast Asia region for the upcoming Northern Hemisphere winter monsoon season (Dec-Jan-Feb), with the highest probabilities over the northern portions of Myanmar, Vietnam, and Lao. Near average air temperatures are predicted over Thailand and Philippines.

Refer to Outlook Bulletin Annex A for reference on what is meant by “above, near, or below normal” in the outlook. For more information on the Northern Hemisphere winter monsoon outlook and further updates on the national scale, the relevant NMSs should be consulted (see Outlook Bulletin Annex B). The review for the JJA 2016 consensus outlook from ASEANCOF-6 is included in the Outlook Bulletin Annex C for reference.

Consensus Maps for DJF 2016-2017

The forum would like to thank the National Meteorological Services of the ASEAN Member countries for conveying their national-level forecasts, the Global Producing Centres, and other participating international climate modelling centres for their products and expertise made available for this climate outlook forum. The forum would also like to thank the WMO Secretariat for providing support and guidance for this bulletin.

Meeting Documents

ASEANCOF-7 Outlook Bulletin
Climate Services Survey Results for ASEAN NMHSs 2016-2017

6th ASEAN COF (31 May, Online Correspondence)

The Sixth ASEAN Climate Outlook Forum (ASEANCOF-6) was organised by the Philippine Atmospheric, Geophysical, and Astronomical Services Administration, with the assistance of the ASEAN Specialized Meteorological Centre (ASMC). The ASEANCOF-was convened via email correspondence between the National Meteorological Services (NMSs) of all 10 ASEAN Member countries: Brunei, Cambodia, Indonesia, Lao, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam and experts from the WMO Global Producing Centres (GPCs): Japan Meteorological Agency, (JMA), National Centers for Environmental Protection (NCEP, NOAA), Centro de Previsão de Tempo e Estudos Climáticos (CPTEC/INPE), United Kingdom Met Office (UKMO), and WMO Lead Center for Long Range Forecast Multi-Model Ensemble (WMO LC-LRFMME).

The aim of the forum is to provide collaboratively developed and consensus-based seasonal climate outlooks and related information on a regional scale. The forum outlook and its activities contribute significantly to one of the key roles of the ASEAN Specialised Meteorological Centre (ASMC), which is to conduct climate and seasonal prediction for ASEAN region through pooling the expertise of ASEAN National Meteorological Services. The consensus outlook for the June-July-August 2016 season for the ASEAN region benefits from the guidance of the WMO GPC model outputs, as well as other global providers. In particular, use is made of the multi-model ensemble forecasts from WMO LC-LRFMME as well as country-level forecasts developed by the participating national experts. The forum reviewed the present climate conditions in the Southeast Asia region, and discussed the various global and regional climatic factors that will influence the JJA season in the area. In particular, the forum took into account the significant influence of the El Niño Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) on the climate over Southeast Asia.

Conditions and Outlook for JJA 2016

Recent analyses of sea surface temperature anomalies (SSTA) and atmospheric conditions over the tropical Pacific have confirmed that the on-going El Niño is in its decaying stage and is likely to end before Northern Hemisphere Summer 2016. In May 2016, positive weak SSTAs were observed confirming that an ENSO-neutral condition is likely to develop in May-June-July 2016 season.

During June-July-August 2016, most international climate outlook models favor the development of La Niña condition. La Niña is characterized by persistent cooler tropical Pacific SST anomalies (-0.5°C or below) and stronger easterly winds over the tropical Pacific Ocean. While varying in local impacts, La Niña events are generally associated with wetter-than-average rainfall conditions over the ASEAN region, especially in the southern half of the region.

The IOD is predicted to be in a persistent negative state starting in JJA 2016 and is likely to continue towards the end of 2016. Negative IOD is generally associated with warmer than SSTA in tropical eastern Indian Ocean in contrast with cooler than normal SSTA in tropical western Indian Ocean. While negative IOD can potentially reinforce the impacts of La Niña, the low skills of climate models for IOD during JJA 2016 should be taken into consideration.

A limited assessment of few models revealed the presence of anomalous anticyclones (at 850-hPa) over northeastern Philippines suggesting weaker-than-normal southwest monsoon and enhanced wet southwesterly wind flow towards northern Southeast Asia.

Taking into consideration the national-level forecasts, the present status of the climate conditions affecting Southeast Asia, and the forecasts available from the GPCs and other global centres, the forum agreed on the following consensus-based outlook for the JJA 2016 season for the Southeast Asia region:

RAINFALL

For the upcoming Northern Hemisphere summer monsoon season (June-July-Aug), there is a slightly enhanced probability of above normal rainfall over the Maritime Continent, which includes most parts of Borneo, Singapore, and southern Sumatra. Slightly enhanced probabilities of below normal rainfall are predicted over northern Philippines. Elsewhere over the region, there are slightly enhanced probabilities for near normal rainfall.

TEMPERATURE

Above normal temperatures are very likely over much of the Southeast Asia region for the upcoming Northern Hemisphere summer monsoon season (June-July-Aug), with the highest probabilities over the Philippines and mainland Southeast Asia.

Refer to Outlook Bulletin Annex A for reference on what is meant by “above, near, or below normal” in the outlook. For more information on the Northern Hemisphere summer monsoon outlook and further updates on the national scale, the relevant NMSs should be consulted (see Outlook Bulletin Annex B). The review for the DJF 2015-16 consensus outlook from ASEANCOF-5 is included in Outlook Bulletin Annex C for reference.

Consensus Maps for JJA 2016

Acknowledgements

The forum would like to thank the National Meteorological Services of the ASEAN Member countries for conveying their national-level forecasts, the Global Producing Centres, and other participating international climate modelling centres for their products and expertise made available for this climate outlook forum. The forum would also like to thank the WMO Secretariat for providing support and guidance for this bulletin.

Meeting Documents

ASEAN COF-6 Outlook Bulletin

5th ASEAN COF (18-19 Nov 2015, Singapore)

The Fifth ASEAN Climate Outlook Forum (ASEANCOF-5) was organised in Singapore from 18-19 November 2015 by the Meteorological Service Singapore (MSS), as host of the ASEAN Specialised Meteorological Centre (ASMC). This event was supported and co-sponsored by the World Meteorological Organization (WMO) and the US Agency for International Development (USAID). ASEANCOF-5 was attended by the National Meteorological Services (NMSs) of all 10 ASEAN Member countries: Brunei, Cambodia, Indonesia, Lao, Malaysia, Myanmar, Philippines, Singapore, Thailand, and Vietnam. The meeting was also attended by experts from the WMO Global Producing Centres (GPC): Bureau of Meteorology (BoM) Australia, China Meteorological Administration (CMA), European Centre for Medium-range Weather Forecasts (ECMWF), Japan Meteorological Agency (JMA), National Centers for Environmental Protection (NCEP, NOAA), WMO Lead Center for Long Range Forecast Multi-Model Ensemble (WMO LC-LRFMME), as well as the APEC Climate Centre (APCC), the International Research Institute for Climate and Society (IRI), and the Regional Integrated Multi-Hazard Early Warning System for Africa and Asia (RIMES). End-user representatives from the hydrological sector, coordinated by the Global Water Partnership South East Asia (GWP-SEA), and from the disaster-risk management agencies, coordinated by the ASEAN Coordinating Centre for Humanitarian Assistance, (AHA Centre) were also present.

Consensus Outlook for the Boreal Winter Monsoon (DJF 2015-2016) Rainfall and Temperature over Southeast Asia

For the upcoming Northern Hemisphere winter monsoon season (Dec-Jan-Feb), there is a strongly enhanced probability of below normal rainfall over the Philippines and the north-eastern part of Borneo Island. Over the eastern Maritime Continent and over the northern part of Mainland Southeast Asia, there are slightly enhanced probabilities of above normal rainfall. Elsewhere over the region, there are slightly enhanced probabilities for normal or below normal rainfall.

Above normal temperatures are very likely over much of the Southeast Asia region for the upcoming Northern Hemisphere winter monsoon season (Dec-Jan-Feb), with the highest probabilities over the central and western Maritime Continent.

Acknowledgements

The forum would like to thank the National Meteorological Services of the ASEAN Member countries for conveying their national-level forecasts, the Global Producing Centres and other participating international climate modelling centres for their products and expertise made available for this climate outlook forum, as well as the participants from the end-user communities coordinated by GWP-SEA and AHA Centre for their contributions. The forum would also like to thank the WMO Secretariat and the USAID for providing support and sponsorship for this event, and to IRI and APCC for coordinating the Pre-COF training workshop.

Meeting Documents

ASEAN COF 5 Meeting Report