Climate Bulletin For Sri Lanka ( 10 February 2023)

                 

Highlights          

 • Moderately heavy rainfall is predicted for the Northern, Eastern, and North Central provinces, and less rainfall is expected for rest of the country during 9th Feb - 15th Feb.

 • During the last week, maximum daily rainfall over Sri Lanka was 189 mm in Vavuniya & 144 mm in Moneragala on 2nd February by storm '90B' and  hydro catchment areas received 56.0 mm. Highest average rainfall 20.1 mm/day received to southern plains of the country.

 • From 31st Jan - 6th Feb, up to 10 m/s of north easterly winds were experienced at 850 mb level over the island. During 10th - 16th 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 9^th February – 15^th February:

Total rainfall by Provinces:    

• 35 mm - Northern
• 25 mm - Eastern, North Central
• 15 mm - North Western 
• ≤ 5 mm - Central, Western, Southern, Sabaragamuwa, Uva

From 16^th February – 22^nd February:

Total rainfall by Provinces:   

• 35 mm - Northern
• 25 mm - Eastern, North Central, Southern
• 15 mm - North Western, Central, Uva
• ≤ 5 mm - Western, Sabaragamuwa

MJO based OLR predictions:

For the next 15 days: 

MJO shall slightly enhance the rainfall during 9^th – 13^th February, moderately suppress the rainfall during 14^th – 18^th February, and significantly suppress the rainfall during 19^th – 23^rd February for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: February 6, 2023 

Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean early - February. 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 25^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 very heavy rainfall over the following area:

Vavuniya

Daily Average Rainfall in the Met stations for previous week of (1^st February – 8^th February) = 11.8 mm

Rmax: 189.2 mm & Rmin: 0.0 mm.

Region	Average rainfall for the Last 8 days
Northern Plains	14.6 mm
Eastern	12.5 mm
Western	6.6 mm
Southern Plains	20.1 mm

The Hydro Catchment Areas recorded 4.6 mm of average rainfall for the last week

Rmax: 56.0 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 some parts of the Eastern, North Central, and Western provinces, driven by the warm SST’s.

Predictions

Rainfall:

During the next week (9^th February – 15^th February), moderately heavy rainfall (≥ 25 mm) is predicted for the Northern, Eastern, and North Central 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 10^th – 16^th 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 slightly enhance the rainfall during 9^th – 13^th February, moderately suppress the rainfall during 14^th – 18^th February, and significantly suppress the rainfall during 19^th – 23^rd 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.