Climate Bulletin For Sri Lanka (14 April 2023)

 

Highlights          

 • Fairly heavy rainfall is predicted for the Southern, Sabaragamuwa, and Western provinces and less rainfall is expected for rest of the country during the 12 th  Apr - 18th Apr.

 • During the last week, average daily rainfall over Sri Lanka was 5.5 mm and  hydro catchment areas received 5.9 mm.

 • From 3rd - 9th Apr, up to 4 m/s of  south easterly winds were experienced at 850 mb level over the island. During 14th Apr - 20th Apr, up to 3 m/s of south westerly winds are expected for the country.

 • Sea surface temperature around Sri Lanka was below normal  for northern half of the island. Land surface temperature remained near normal. 

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 12^th April – 18^th April:

Total rainfall by Provinces:    

• 55 mm - Southern, Sabaragamuwa, Western
• 45 mm - Central
• 35 mm - North Western, North Central
• 25 mm - Eastern
• ≤ 15 mm - Uva, Northern

From 19^th April – 25^th April:

Total rainfall by Provinces:   

• 75 mm - Sabaragamuwa
• 65 mm - Western, Southern
• 45 mm - North Western, Central
• 35 mm - North Central
• 25 mm - Uva, Eastern
• ≤ 15 m - Northern

MJO based OLR predictions:

For the next 15 days: 

MJO shall significantly suppress the rainfall during 12^th – 16^th April, moderately suppress the rainfall during 17^th - 21^st April and near normal the rainfall during 22^nd - 26^th April for Sri Lanka

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: April 10, 2023 

Equatorial sea surface temperatures (SSTs) are near average across most of the Pacific Ocean mid- April. The tropical Pacific atmosphere is consistent with ENSO-neutral conditions. A large majority of the models indicate ENSO-neutral conditions are expected to continue through the Northern Hemisphere spring and early summer 2023.

Indian Sea Sate

Sea surface temperature around Sri Lanka was below - 0.5 ℃ to the northern half of the country in 1^st February, 2023. Across the Indian Ocean, a classical negative Indian Ocean Dipole prevails as is typical during a La Niña.

 

Interpretation

Monitoring

Rainfall:

During the last two weeks, there had been heavy rainfall over the following area: Kurunegala

         

Daily Average Rainfall in the Met stations for previous week of (4^th April – 11^th April) = 5.5 mm

Maximum Daily Rainfall: 145.4 mm & Minimum Daily Rainfall: 0.0 mm. 

Region	Average rainfall for the Last 8 days
Northern Plains	2.5 mm
Eastern	1.3 mm
Western	10.4 mm
Southern Plains	8.3 mm

The Hydro Catchment Areas recorded 5.9 mm of average rainfall for the last week.

Maximum Daily Rainfall: 73.0 mm & Minimum Daily Rainfall: 0.0 mm.

Wind:

South easterly winds prevailed in the sea area and around the island last week.

Temperature: 

The temperature anomalies were near normal for the country driven by the warm SST’s.

Predictions

Rainfall:

During the next week (12^th April – 18^th April), fairly heavy rainfall (55 mm) is predicted for the Southern, Sabaragamuwa, and Western provinces, and less rainfall is expected for the rest of the country.

Temperature:

The temperature will remain above normal for some parts of the Northern, North Western, North Central, Uva, Eastern, Central, and Southern provinces during 14^th April – 20^th April.

Teleconnections:

ENSO-neutral conditions are expected to continue through the Northern Hemisphere spring and early summer2023.

MJO shall significantly suppress the rainfall during 12^th – 16^th April, moderately suppress the rainfall during 17^th - 21^st April and near normal the rainfall during 22^nd - 26^th April for Sri Lanka.

Seasonal Precipitation: 

The precipitation forecast for the April-May-June, 2023 season shows a higher tendency of below-normal precipitation for the country except Northern Province.