Climate Bulletin For Sri Lanka (27 January 2023)

               

Highlights          

 • Fairly heavy rainfall is predicted for the Eastern, North Central, Northern, North Western, Central, Uva provinces, and moderately heavy rainfall is expected for rest of the country during 27th Jan - 2nd Feb. Highest rainfall is expected from 31st Jan - 2nd Feb as there is a storm in Bay of Bengal.

 • During the last week, maximum daily rainfall over Sri Lanka was 71.2 mm and  hydro catchment areas received 65.0 mm and highest average rainfall 7.1 mm in the southern plains of the country.

 • From 18th - 24th Jan, up to 8m/s of north easterly winds were experienced at 850 mb level over the island. During 28th Jan - 3rd Feb, 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 27^th January – 2^nd February:

Total rainfall by Provinces:    

• 65 mm - Eastern, North Central
• 55 mm - Northern, North Western, Central, Uva
• 45 mm - Western, Sabaragamuwa
• 35 mm - Southern

From 3^rd February – 9^th February:

Total rainfall by Provinces:   

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

MJO based OLR predictions:

For the next 15 days: 

MJO shall moderately enhance the rainfall during 27^th – 31^st January, slightly enhance the rainfall during 1^st – 5^th February, and slightly suppress the rainfall during 6^th – 10^th February for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: January 23, 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 18^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: Ampara

Daily Average Rainfall in the Met stations for previous week of (19^th January – 25^th January) = 3.5 mm

Rmax: 71.2 mm & Rmin: 0.0 mm.

Region	Average rainfall for the Last 8 days
Northern Plains	2.6 mm
Eastern	4.2 mm
Western	3.1 mm
Southern Plains	7.1 mm

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

Rmax: 65.0 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 near neutral for the whole county, driven by the warm SST’s.

Predictions

Rainfall:

During the next week (27^th January – 2^nd February), fairly heavy rainfall (≥ 55 mm) is predicted for the Eastern, North Central, Northern, North Western, Central, Uva provinces, and moderately heavy rainfall is expected for rest of the country.

Temperature:

The temperature will remain below normal for some parts of the Central, Uva, and Eastern provinces during 28^th January – 3^rd February.

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 moderately enhance the rainfall during 27^th – 31^st January, slightly enhance the rainfall during 1^st – 5^th February, and slightly suppress the rainfall during 6^th – 10^th 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.