Climate Bulletin For Sri Lanka (25 March 2022)

Highlights          

                   

 • Up to 75 mm of fairly heavy rainfall is expected for the Central province from 23rd - 29th March while other provinces are expected to receive less.

 • 3.6 mm average daily rainfall was experienced for the last week in the met stations, with max of 111 mm in Kegalle on 17 March.

 • From 14th - 20th March, up to 3 -6m/s Southwesterlies were experienced over the island.

 • Sea surface temperatures were neutral around the island.

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 23^rd – 29^th March: 

Total rainfall by Provinces:

• 75 mm - Central
• 45 mm - North Western
• 25 mm - North Central, Western, Sabaragamuwa, Southern, Eastern
• 15 mm - Uva

From 30^th March – 5^th April: 

Total rainfall by Provinces:

• 85 mm - Central
• 55 mm - North Western, Eastern
• 35 mm - North Central, Western, Sabaragamuwa, Southern, Uva

MJO based OLR predictions:

For the next 15 days: 

MJO shall neutral during 23^rd – 27^th March; and slightly enhance the rainfall during 28^th March - 6^th April.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: March 16, 2022 

Equatorial sea surface temperatures (SSTs) are below average across the East Central and Eastern Pacific Ocean in mid-March. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate La Niña is favored to continue into the Northern Hemisphere summer, with a 40-50% chance of La Niña or ENSO neutral thereafter.

Indian Sea Sate

Sea surface temperatures were neutral around the island. 

Interpretation

Monitoring

Rainfall: 

During the last two weeks, there had been heavy rainfall over the following province: Sabaragamuwa.

Meteorology stations were recorded 3.6 mm of average daily rainfall and the Rmax: 47.2mm & Rmin: 0mm for entire island for the last week.

Region	Meteorology stations	Average rainfall for the Last 8 days
Northern Plains	Jaffna, Mannar, Anuradhapura, Puttalam, Maha Illuppallama, Vavuniya, Mullaitivu	0.07 mm
Eastern	Trincomalee, Batticaloa, Potuvil, Badulla, Bandarawela, Moneragala, Polonnaruwa	5.79 mm
Western	Nuawara Eliya, Kurunegala, Colombo, Ratnapura, Galle, Katugastota, Katunayake, Ratmalana	4.31 mm
Southern Plains	Hambantota, Mattala	6.35 mm

The mean of annual rainfall = 23.49 mm

Recorded average rainfall for the week of 14^th – 21^st March = 3.60 mm

Meanwhile the Hydro Catchment Areas were recorded 6.52mm of average rainfall for the last week range Rmax: 79.7mm & Rmin: 0 mm. 

Wind:

Southwesterly winds prevailed in the sea area surrounding the island last week. 

Temperature: 

The temperature anomalies were below normal for the Northern half and near-neutral for the rest of the country, driven by the warm SST’s.

Predictions

Rainfall:

During the next week (23^rd – 29^th March) fairly heavy rainfall is predicted for Central province.

Temperature:

The temperature remains slightly above normal in the Northern province during 25^th March – 2^nd April. 

Teleconnections:

La Nina - The SST forecast indicates that La Niña is favored to continue into the Northern Hemisphere summer (June-August 2022).

MJO shall neutral during 23^rd – 27^th March; and slightly enhance the rainfall during 28^th March - 6^th April.

Seasonal Precipitation: 

The precipitation forecast for the April-May-June season shows above-normal precipitation for the island, while some parts of the southern province remain neutral.