Climate Bulletin For Sri Lanka ( 3 March 2023)

  

Highlights          

 • Fairly heavy rainfall is predicted for the Southern, Eastern, Sabaragamuwa, and Uva provinces and moderately heavy rainfall is expected for rest of the country during 2nd – 8th March.

 • During the last week, maximum daily rainfall over Sri Lanka was 120 mm in Matale and  hydro catchment areas received 52.5 mm. Highest average rainfall 5.3 mm/day was received to Eastern plains.

 • From 21st - 27th Feb, up to 6 m/s of north easterly winds were experienced at 850 mb level over the island. During 3rd - 9th Mar easterly 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 2^nd March – 8^th March:

Total rainfall by Provinces:    

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

From 9^th March – 15^th March:

Total rainfall by Provinces:   

• 105 mm - Southern
• 85 mm - Sabaragamuwa
• 75 mm - Eastern, Uva
• 65 mm - Western, Central, North Central, Northern
• 45 mm - North Western

MJO based OLR predictions:

For the next 15 days: 

MJO shall slightly suppress the rainfall during 2^nd March – 6^th March, and moderately suppress the rainfall during 7^th March – 16^th March for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: February 27, 2023 

Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean late - February. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate ENSO-neutral conditions will begin within the next couple of months, and persist through the Northern Hemisphere spring and early summer.

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 areas: Matale, Ratnapura

Daily Average Rainfall in the Met stations for previous week of (22^nd February – 1^st March) = 3.2 mm

Rmax: 55.8 mm & Rmin: 0.0 mm.

Region	Average rainfall for the Last 8 days
Northern Plains	1.2 mm
Eastern	5.3 mm
Western	3.0 mm
Southern Plains	3.0 mm

The Hydro Catchment Areas recorded 3.5 mm of average rainfall for the last week 

Rmax: 52.5 mm & Rmin: 0.0 mm.

Wind:

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

Temperature: 

he temperature anomalies were below normal for some parts of the Northern and North Central provinces, driven by the warm SST’s.

Predictions

Rainfall:

During the next week (2^nd March – 8^th March), fairly heavy rainfall (≥ 55 mm) is predicted for the Southern, Eastern, Sabaragamuwa, and Uva provinces, and moderately heavy rainfall is expected for rest of the country.

Temperature:

The temperature will remain above normal for some parts of the Uva, Sabaragamuwa, North Western and Northern provinces and below normal for some parts of the Central province during 3^rd March – 9^th March.

Teleconnections:

ENSO-neutral conditions will begin within the next couple of months, and persist through the Northern Hemisphere spring and early summer.

MJO shall slightly suppress the rainfall during 2^nd March – 6^th March, and moderately suppress the rainfall during 7^th March – 16^th March for Sri Lanka.

Seasonal Precipitation: 

The precipitation forecast for the March-April-May 2023 season shows a higher tendency of above-normal precipitation for southern half of the country.