OVERVIEW: A monsoon trough extending across the upper North of Thailand and upper Lao PDR, combined with a strong Southwest Monsoon over the Bay of Bengal, Andaman Sea, and the Gulf of Thailand, is prevailing across mainland Southeast Asia. Over the Gulf of Tonkin, Tropical Cyclone NARRA is tracking near the northern Vietnam coast and is expected to move toward southern China in the coming days. As of 1000 HRS UTC+7, the centre of Tropical Cyclone NARRA was located at approximately 20.6°N, 107.9°E, over the sea area north of Bach Long Vi Special Economic Zone, about 135km east of Quang Ninh and about 140km east of Hai Phong. Together, these systems are bringing thunderstorms and heavy rainfall across Lao PDR, Myanmar, Thailand, and Viet Nam. (DMH Lao PDR, DMH Myanmar, TMD Thailand, NCHMF Viet Nam.
STRENGTH & MOVEMENT: According to NCHMF, Tropical Cyclone NARRA has maximum sustained winds at Level 8 (62-88 km/h), central pressure at 993 hPa, moving south at approximately 3 km/h
FORECAST:
- Tropical Cyclone NARRA is forecast to track southeast at around 3 km/h through 24 August, intensifying to Level 9 with gusts to Level 11 east of Bach Long Vi, before shifting east-northeast at 3–5 km/h into the eastern Bac Bo Gulf by 25 August, maintaining Level 9 strength with gusts to Level 11. It is then expected to turn north-northeast at 5–10 km/h and move inland over southwest Guangxi Province, China by 26 August, weakening to a tropical depression with Level 7 winds and gusts to Level 9, before curving north and then north-northwest over the following 72–96 hours and weakening further into a low-pressure area. (NCHMF)
- The Southwest Monsoon is expected to remain strong over the Bay of Bengal and Andaman Sea in the coming days, continuing to bring widespread thunderstorms and heavy rainfall across Myanmar, Lao PDR, and Thailand, with locally heavy to very heavy rain in Ayeyarwady Region, northern Lao provinces already affected by flooding, and Thailand’s North, upper Northeast, Central, and East. (DMH Lao PDR, DMH Myanmar, TMD)
HAZARDS:
Tropical Cyclone NARRA
- Risk of rough seas and damage to fishing boats, cargo and tourist vessels, aquaculture cages, anchorages, and coastal structures across the Bac Bo Gulf and coastal waters of Quang Ninh and Hai Phong; fishing, transport, and tourism activity may be disrupted. Coastal wind (Level 6–7, gusts to Level 8–9) in Quang Ninh and Hai Phong may cause roof damage, downed trees and billboards, and disruption to power and traffic. Heavy rainfall associated with NARRA, locally exceeding 300mm in Quang Ninh, Hai Phong, Lang Son, Bac Ninh, Hung Yen, and Ninh Binh, raises risk of urban and industrial flooding, and flash floods and landslides in mountainous areas of Northeast Bo, southern Phu Tho, and Thanh Hoa. Risk of thunderstorms, tornadoes, and strong wind gusts from NARRA’s circulation. (NCHMF)
Southwest Monsoon
- Continued risk of flash floods, river overflow, and landslides across Myanmar, Lao PDR, and Thailand, along with rough seas and squally winds along the Andaman coast, as the Southwest Monsoon remains strong over the Bay of Bengal and Andaman Sea. (DMH Lao PDR, DMH Myanmar, TMD).
ANTICIPATED RISKS:
- High antecedent rainfall from weeks of continuous, prolonged flooding across northern Mainland Southeast Asia, especially in mountainside and riverside areas, increases the risk of flash floods and landslides as further rain falls on already-saturated ground.
- Three other weather systems are being monitored in the Western Pacific basin: the remnants of Tropical Cyclone GAENARI (Neneng), located about 565 km north of Batanes; Tropical Cyclone 19W about 1,205 km east of Eastern Visayas; and Tropical Cyclone SAUDEL, about 2,255 km east of extreme Northern Luzon. Latest forecasts do not indicate landfall scenarios in the ASEAN region, but these systems may potentially influence prevailing weather conditions. (PAGASA)
IMPACTS:
- LAO PDR – NDMO Lao PDR reported the following impacts as of 22 August 2026 (cumulative since onset on 3 July 2026, Tropical Storm MAYSAK and heavy rain, updated from the initial impacts reported in Flash Update No. 1 for the Flooding in Lao PDR)
- 9 provinces affected: Luang Nam Tha, Borkeo, Xayaboury, Bolikhamxay, Khammouane, Savannakhet, Saravan, Sekong, Champasak — 54 districts, 972 villages
- 187,734 people (44,976 families) affected, including 105,371 female
- 6 deaths,1 injury
- 7,528 people (213 families) have been evacuated from 17 villages while 177 people (68 families) relocated to relatives’ homes
- 10 houses destroyed, 990 damaged
- 57 schools and 9 health facilities affected
- Approximately 310 km of roads affected
- Approximately USD 11M estimated total losses
- MYANMAR – In addition to the affected population reported in Flash Update No. 1 for the Flooding in Ayeyarwady and Kayin, DDM Myanmar reported:
- 99 households (427 people) had relocated to temporary flood relief centres following the flooding due to overflow of the Thanlwin (Salween) River. This brings the total affected population in Ayeyarwady and Kayin to 65,827, with two (2) deaths and 15K displaced households as previously reported.
- Data collection and assessments are still ongoing.
- THAILAND: According to DDPM Thailand, from 18-23 August, a total of 10 provinces were affected at peak (Phayao, Nan, Mae Hong Son, Sukhothai, Phitsanulok, Phetchabun, Uttaradit, Sakon Nakhon, Nakhon Phanom, Ubon Ratchathani) with the following impacts:
- 79,509 people (27,910 households) were affected at peak
- 3 deaths (1 in Pua District, 2 in Tha Wang Pha District, Nan Province)
- Current Situation: Flooding remains in 4 provinces (Nan, Sukhothai, Phitsanulok, Ubon Ratchathani) covering 9 districts, 19 sub-districts, and 78 villages, with 6,152 people (2,005 households) still affected, with the following details per province:
- Nan: 5,750 people (1,850 households) remain affected, down from a peak of 67,129 people (23,827 households); water levels receding.
- Sukhothai: 222 people (71 households) remain affected, down from a peak of 5,259 people (1,977 households); water levels receding.
- Phitsanulok: 34 people (19 households) affected, all evacuated; water levels stable
- Ubon Ratchathani: 146 people (65 households) affected; water levels stable
- VIET NAM – According to VDDMA from Tropical Cyclone Narra and the accompanying heavy rain caused the following damage in Lang Son, Quang Ninh, and Bac Ninh provinces, as of 23 August 2026:
- 1 death due to a landslide
- 200 houses damaged or with roofs blown off, and 733 houses flooded, all in Lang Son
- 2,864 ha of crops flooded or damaged (Lang Son: 1,100 ha; Bac Ninh: 1,687 ha; Quang Ninh: 78 ha)
- 100 head of livestock and 6,000 poultry killed, in Lang Son
- 603 landslide and flooding points causing road blockages (Lang Son: 600; Bac Ninh: 3)
- Data collection and assessments are still ongoing.
PREPAREDNESS AND RESPONSE:
- LAO PDR – NDMO Lao PDR is closely monitoring the situation and coordinating with provincial disaster management offices, with damage assessments and data collection underway in affected provinces, while DMH Lao PDR continues to monitor the prevailing weather systems and provide regular updates and advisories.
- MYANMAR – DDM Myanmar, together with relevant ministries, technical experts, military personnel, firefighters, civil society organisations, and charitable organisation, continues efforts to respond to the impacts of the widespread flooding, including continued provision of food, drinking water, and essential healthcare services to affected communities. DMH Myanmar continues to monitor prevailing weather systems and provide regular updates and advisories.
- THAILAND – DDPM Thailand, together with provincial authorities, continues to deploy personnel, machinery, and relief supplies to support evacuation, drainage, and relief operations in affected provinces, alongside coordinated support from the Royal Volunteer 904 Operations Centre and partner organisations. TMD continues to monitor the situation and issue regular warnings and advisories.
- VIET NAM – The Prime Minister, the National Steering Committee for Civil Defense, and relevant ministries continue to direct response efforts across affected northern provinces, with VDDMA coordinating reservoir and dyke safety measures, public safety alerts, and the evacuation of at-risk households. NCHMF continues to monitor Tropical Cyclone NARRA and issue regular forecasts, warnings, and advisories.
The AHA Centre continues to monitor for further developments in close coordination with NDMO Lao PDR, DDM Myanmar, DDPM Thailand, and VDDMA Viet Nam, issue updates as necessary, and stands ready to support affected ASEAN Member States should the need arise.
DATA SOURCES
ASEAN Disaster Monitoring & Response System (DMRS), ASEAN Disaster Information Network (ADINet); ASEAN Specialised Meteorological Centre (ASMC);
Lao PDR: NDMO, DMH;
Myanmar: DDM, DMH;
Philippines: PAGASA;
Thailand: DDPM, TMD;
Viet Nam: VDDMA, NCHMF;
Verified news media agencies
