Climate Bulletin For Sri Lanka (20 January 2023)

              

Highlights          

 • Fairly heavy rainfall is predicted for the Eastern, Uva, Central, North Central provinces and ≥ 55 mm rainfall is predicted for the Southern, Sabaragamuwa, North Western, and Western provinces during 19th - 25th January.

 • During the last week, maximum daily rainfall over Sri Lanka was 38.0 mm and hydro catchment areas received 37.0 mm.

 • From 10th - 16th Jan, up to 8m/s of north easterly winds were experienced at 850 mb level over the island. During 20th - 26th Jan, north easterly winds are expected for the country.

 • Sea surface temperature around Sri Lanka was near-neutral  for the entire island. Land surface temperature remained near normal. 

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 19^th January – 25^th January:

Total rainfall by Provinces:    

• 95 mm - Eastern
• 85 mm - Uva
• 75 mm - Central, North Central
• 65 mm - Southern, Sabaragamuwa, North Western
• 55 mm - Western
• 35 mm - Northern

From 26^th January – 1^st February:

Total rainfall by Provinces:   

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

MJO based OLR predictions:

For the next 15 days: 

MJO shall slightly enhance the rainfall during 19^th – 23^rd January, moderately enhance the rainfall during 24^th January – 2^nd February for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: January 17, 2023 

Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean mid - January. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate a transition from La Niña to ENSO-neutral anticipate during the February-April 2023 season by Northern Hemisphere spring (March-May 2023), the chance for ENSO-neutral is 82%.

Indian Sea Sate

Sea surface temperature around Sri Lanka was near neutral for the whole country in 11^th January, 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: Colombo

Daily Average Rainfall in the Met stations for previous week of (11^th January – 18^th January) = 1.6 mm

Rmax: 38.0 mm & Rmin: 0.0 mm.

Region	Average rainfall for the Last 8 days
Northern Plains	0.8 mm
Eastern	1.9 mm
Western	2.0 mm
Southern Plains	0.7 mm

The Hydro Catchment Areas recorded 2.5 mm of average rainfall for the last week

Rmax: 37.0 mm & Rmin: 0.0 mm.

Wind:

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

Temperature: 

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

Predictions

Rainfall:

During the next week (19^th – 25^th January), fairly heavy rainfall (≥ 75 mm) is predicted for the Eastern, Uva, Central, North Central provinces, and ≥ 55 mm is predicted for the Southern, Sabaragamuwa, North Western, Western provinces and less rainfall is expected for rest of the country.

Temperature:

The temperature will remain below normal for some parts of the Central and Uva provinces during 20^th – 26^th January.

Teleconnections:

A transition from La Niña to ENSO-neutral is anticipated during the February-April 2023 season by Northern Hemisphere spring (March-May 2023), the chance for ENSO-neutral is 82%.

MJO shall slightly enhance the rainfall during 19^th – 23^rd January, moderately enhance the rainfall during 24^th January – 2^nd February for Sri Lanka.

Seasonal Precipitation: 

The precipitation forecast for the February-March-April 2023 season shows a higher tendency of near-normal precipitation for the country.