Category Archives: Fortnightly Weather Outlook

CR58

April 1, 2022

Subseasonal Weather Outlook (4 – 17 April 2022)

Issued: 1 April 2022
First forecast week: 4 April – 10 April
Second forecast week: 11 April – 17 April

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

Wetter conditions are expected over the band covering the Malay Peninsula, southeastern Mainland Southeast Asia, and the Philippines in Week 1 (4 – 10 April). These wetter conditions are expected to persist for much of the region in Week 2 (11 – 17 April), apart from over parts of the Malay Peninsula and southern Philippines.

Drier conditions are predicted for much of the southern half of the Maritime Continent over the next fortnight (4 – 17 April). Drier conditions are also predicted over central and northeastern Mainland Southeast Asia in Week 1 (4 – 10 April) only.

Warmer conditions than usual are predicted over much of the southern half of the Maritime Continent in the next fortnight (4 – 17 April), in line with the drier conditions predicted. Cooler temperatures than usual are expected over much of Mainland Southeast Asia and the northern half of the Malay Peninsula in Week 1 (4 – 10 April).

No discernible Madden-Julian Oscillation (MJO) signal was present at the end of March. Most models predict no significant MJO activity 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.

March 18, 2022

Subseasonal Weather Outlook (21 March – 3 April 2022)

Issued: 18 March 2022
First forecast week: 21 March – 27 March
Second forecast week: 28 March – 3 April

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

Wetter conditions are expected over much of western and central Mainland Southeast Asia in the next fortnight (21 March – 3 April). In Week 1 (21 – 27 March), the highest probability of wetter conditions is over Myanmar, Thailand and Lao PDR. In Week 2 (28 March – 3 April), these wetter conditions are expected to ease.

Elsewhere, wetter conditions are expected over southeastern parts of the Maritime Continent in Week 1 (21 – 27 March). In Week 2 (28 March – 3 April), wetter conditions are expected over the Philippines and extending westwards to the coastal areas of southeastern Mainland Southeast Asia.

Conversely, drier conditions than usual are expected to develop over Sumatra in Week 1 (21 – 27 March) and extend eastwards over much of Borneo in Week 2 (28 March – 3 April).

Warmer conditions than usual are expected over much of the western and central equatorial region in the next fortnight (21 March – 3 April), in line with the drier conditions predicted. Cooler temperatures than usual are expected over central and eastern Mainland Southeast Asia in Week 2 (28 March – 3 April).

A moderate Madden-Julian Oscillation (MJO) signal was present over the Indian Ocean (Phase 2) in the middle of March. Most models predict this MJO signal to continue propagating eastwards and reaching the Maritime Continent (Phase 4) during the first week of the forecast period. Some models predict this signal to continue propagating through the Maritime Continent (Phase 5) and Western Pacific (Phase 6) in Week 2, while others predict the signal to decay.

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.

March 4, 2022

Subseasonal Weather Outlook (7 – 20 March 2022)

Issued: 4 March 2022
First forecast week: 7 March – 13 March
Second forecast week: 14 March – 20 March

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

Wetter conditions are expected over much of the Philippines, northern Borneo and northern Sulawesi in the next fortnight (7 – 20 March).

Wetter conditions are also expected in Week 1 (7 – 13 March) over the western Maritime Continent and may extend north to southern parts of Mainland Southeast Asia, even though the anomalies for the latter are not expected to be large. These wetter conditions are expected to ease in Week 2 (14 – 20 March).

No significant regional temperature anomalies are expected in the next fortnight (7 – 20 March).

By the end of February 2022, the Madden-Julian Oscillation (MJO) signal had decayed over the Indian Ocean (Phase 3) and has become indiscernible. Most models predict no significant MJO activity during the forecast period.

February 18, 2022

Subseasonal Weather Outlook (21 February – 6 March 2022)

Issued: 18 February 2022
First forecast week: 21 February – 27 February
Second forecast week: 28 February – 6 March

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

Wetter conditions are expected in the next fortnight (21 February – 6 March) for much of the region encompassing the Malay Peninsula, coastal parts of southeastern Mainland Southeast Asia, the Philippines, and northeast Borneo. The highest likelihood of wetter conditions is over the Malay Peninsula in Week 1 (21 – 27 February) and over the Philippines in Week 2 (28 February – 6 March).

Wetter conditions are also expected in Week 1 (21 – 27 February) over southeastern parts of the Maritime Continent.

Cooler than usual conditions are expected for Mainland Southeast Asia in Week 1 (21– 27 February), easing in Week 2 (28 February – 6 March).

The Madden-Julian Oscillation (MJO) signal was present over the Indian Ocean (Phase 3) in the middle of February based on the RMM Index. Most models predict the MJO signal to propagate eastwards through the Maritime Continent (Phases 4 and 5) during the forecast period.

February 4, 2022

Subseasonal Weather Outlook (7 – 20 February 2022)

Issued: 4 February 2022
First forecast week: 7 February – 13 February
Second forecast week: 14 February – 20 February

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

Wetter conditions are expected in the next fortnight (7 – 20 February) over the region between the equator and 10°N (including the Malay Peninsula, northern Sumatra, northern Borneo and southern Philippines) and also the southern Maritime Continent.

Drier conditions are expected in the next fortnight (7 – 20 February) over central and southern Sumatra.

For temperature, warmer than usual conditions are expected over southern Mainland Southeast Asia and parts of the Philippines in Week 1 (7 – 13 February). Warmer conditions are also expected over the region around Sumatra in the next fortnight (7 – 20 February), in line with the drier conditions predicted.

Cooler than usual conditions are expected for northern parts of Mainland Southeast Asia in the next fortnight (7 – 20 February).

At the start of February, there was no Madden-Julian Oscillation (MJO) signal. Some models predict an MJO to develop over the Indian Ocean (Phase 3) in Week 1 and then propagate through the Maritime Continent (Phases 4 and 5), while other models predict the MJO to remain weak over 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.

January 21, 2022

Subseasonal Weather Outlook (24 January – 6 February 2022)

Issued 21 January 2022
First forecast week: 24 January – 30 January
Second forecast week: 31 January – 6 February

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

In Week 1 (24 – 30 January), drier conditions are predicted over much of the western and southern Maritime Continent. Also in Week 1, wetter conditions are predicted over northeastern parts of the Maritime Continent (in particular for the Philippines).

For temperature, warmer than usual conditions are predicted for much of the central part of Southeast Asia (central and eastern Mainland Southeast Asia, the western half of the Maritime Continent) and the northern Philippines in Week 1 (24 – 30 January). In Week 2 (31 January – 6 February), these warmer conditions are expected to ease, apart from over the coastal regions of eastern Mainland Southeast Asia.

Cooler than usual conditions are predicted for northwestern Mainland Southeast Asia in the next fortnight (24 January – 6 February).

By the middle of January, the previous Madden-Julian Oscillation (MJO) signal had decayed. Most models predict no significant MJO activity during the forecast period.

January 7, 2022

Subseasonal Weather Outlook (10 – 23 January 2022)

Issued 7 January 2022
First forecast week: 10 January – 16 January
Second forecast week: 17 January – 23 January

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

Drier conditions are predicted in the next fortnight (10 – 23 January) over a band that includes the Malay Peninsula, southern Viet Nam, and much of the northern Philippines and surrounding area.

Wetter conditions are predicted in Week 1 (10 – 16 January) over central parts of the Maritime Continent (in particular for western Borneo and Java). These wetter conditions are expected to ease in Week 2 (17 – 23 January), although there is a chance that they remain over the region around Java. Also in Week 2, wetter conditions are predicted to develop over parts of the central and southern Philippines.

No significant regional temperature anomalies are expected in the next fortnight (10 – 23 January).

Based on the RMM index, a Madden-Julian Oscillation (MJO) signal was present over the Western Pacific (Phase 7) at the start of January, although the signal has been less coherent in part due to the background La Niña state. As with the previous outlook, while some models predict this signal to propagate slowly eastwards, others predict the signal to decay in Phase 7.

December 24, 2021

Subseasonal Weather Outlook (27 December 2021 – 9 January 2022)

Issued: 24 December 2021
First forecast week: 27 December – 2 January
Second forecast week: 3 January – 9 January

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

In Week 1 (27 December – 2 January), wetter conditions are expected over much of the Philippines, northern Borneo and northern Sulawesi. However, these wetter conditions are highly dependent on the tropical cyclone development. Also in Week 1, an increased chance of wetter conditions is predicted over parts of Viet Nam and the Malay Peninsula.

Cooler than usual temperature is expected over much of central and eastern Mainland Southeast Asia in Week 1 (27 December – 2 January) associated with a strengthening of the northeasterly winds, bringing cooler air from the northern Asian landmass. In Week 2 (3 – 9 January), these cooler conditions are expected to ease for much of this area.

Warmer than usual temperature is expected over southeastern parts of the Maritime Continent in Week 1 (27 December – 2 January).

Based on the RMM index, a Madden-Julian Oscillation (MJO) signal was present over the Western Pacific (Phases 6 and 7) in December. Some models predict this signal to continue propagating slowly through the Western Pacific, while others predict the signal to decay in Phase 7.

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.

December 10, 2021

Subseasonal Weather Outlook (13 – 26 December 2021)

Issued 10 December 2021
First forecast week: 13 December – 19 December
Second forecast week: 20 December – 26 December

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

In Week 1 (13 – 19 December), wetter conditions are expected over central parts of the Philippines and the eastern coastal regions of Mainland Southeast Asia. However, these wetter conditions are highly dependent on the tropical cyclone development. Also in Week 1, wetter conditions are expected over both western and eastern parts of the equatorial region.

Drier conditions are expected over the central equatorial region in Week 2 (20 – 26 December).

Warmer than usual temperature is expected over the southeastern parts of the Maritime Continent in Week 1 (13 – 19 December).

A Madden-Julian Oscillation (MJO) signal propagated eastward from the eastern Maritime Continent (Phase 5) to the Western Pacific (Phases 6 and 7) in the first fortnight of December. However, most models predict this signal to decay in the second week of the forecast period as it propagates eastwards towards Western Hemisphere and Africa (Phase 8).

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.

November 26, 2021

Subseasonal Weather Outlook (29 November – 12 December 2021)

Issued 26 November 2021
First forecast week: 29 November – 5 December
Second forecast week: 6 November – 12 December

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

Wetter conditions are expected over southern Mainland Southeast Asia, parts of the Philippines, and the southeastern Maritime Continent in Week 1 (29 November – 5 December). These wetter conditions are likely to persist over coastal parts of Viet Nam and the Philippines in Week 2 (6 – 12 December).

Drier conditions are expected over the western and central equatorial region in Week 1 (29 November – 5 December).

For temperature, cooler than usual temperature is expected over much of Mainland Southeast Asia in the next fortnight (29 November – 12 December). Warmer than usual temperature is expected over the western and central equatorial region in Week 1 (29 November – 5 December), in line with the drier conditions predicted.

No coherent Madden-Julian Oscillation (MJO) signal was present towards the end of November. Some models predict an MJO signal to propagate eastward through the Maritime Continent (Phases 4 and 5) and the Western Pacific (Phases 6 and 7) in the forecast period.