Sri Lanka: Adverse weather forecast across much of the country through at least May 18

Severe weather is forecast across much of Sri Lanka through at least May 18. Showers and thunderstorms are expected across much of the country on May 9, with rainfall totals of over 7.5 cm (3 inches) expected in North-Central, Central, Sabaragamuwa, Eastern and Uva provinces, and Mullaitivu District.

The Sri Lankan Department of Meteorology has issued an amber advisory (the middle level on a three-tier scale) for severe lightning May 9. The advisory warns that thundershowers accompanied by severe lightning are likely over parts of Western, Sabaragamuwa, Southern, Eastern, Uva, and North-Central provinces, as well as in Matale, Mullaitivu, and Kurunegala districts. There is a high risk of severe lightning in these areas and a moderate risk across the rest of the country. The public is advised to take precautions during thunderstorm activity, such as sheltering indoors.

The wet weather is expected to continue in many areas May 10-18, with daily rainfall totals of 5-8 cm (2-3.1 inches) possible in places. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Thunderstorms will be capable of producing strong winds, heavy rainfall, and lightning. Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rainfall has saturated the soil.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are possible where significant flooding, strong winds, or landslides impact utility networks.

The severe weather will likely contribute to transport disruptions throughout the country. Traffic and commercial trucking delays might occur along regional highways. Flooding downpours could inundate some low-lying roads in areas with poor drainage. Strong winds might also pose a hazard to high-profile vehicles. Hazardous weather conditions might cause flight delays and cancellations at regional airports.