Climate Bulletin For Sri Lanka (11 November 2022)

    

Highlights          

 • Heavy rainfall (≥135mm) is predicted for the Sabaragamuwa, Western, Northern, and Southern provinces during 9th - 15th Nov. During 10th - 22nd Nov heavy rainfall is predicted for Southern and Sabaragamuwa provinces.

 • During the last week, the average daily rainfall over Sri Lanka was 16.8 mm & hydro catchment areas received 15.3 mm on average.

 • From 31st Oct  -6th Nov, up to 5m/s of north-westerly and north-easterly winds were experienced at 850 mb level over the island. During 10th - 16th Nov, westerly winds are expected to the country .

 • Sea surface temperature around Sri Lanka was above normal to the whole country in late - October. Land surface temperature remained near normal.

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 9^th November– 15^th November:

Total rainfall by Provinces:   

• > 135 mm - Western, Southern, Northern, Sabaragamuwa
•    135 mm - Eastern, Central
•    125 mm - North Western, North Central, Uva

From 16^th November– 22^nd November:

Total rainfall by Provinces:

• > 135 mm - Southern
•   135 mm - Sabaragamuwa
•   115 mm - Western
•    85 mm - Northern, Central, Uva
•    65 mm - Eastern, North Western
•    55 mm - North Central

MJO based OLR predictions:

For the next 15 days: 

MJO shall near neutral the rainfall during 9^th– 23^rd November for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: November 7, 2022 

Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean early - November. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate La Niña is favored to continue through during the Northern Hemisphere winter (December-February) 2022-23, with a 54% chance for ENSO-neutral in February-April 2023.

Indian Sea Sate

Sea surface temperature around Sri Lanka was above 0.5℃ to the whole country in 26^th October, 2022. 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: Kegalle, Mullaitivu, Galle and Rathnapura

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

16.8 mm

Rmax: 116.0 mm & Rmin: 0.0 mm.

Region	Average rainfall for the Last 8 days
Northern Plains	15.5 mm
Eastern	20.0 mm
Western	14.6 mm
Southern Plains	19.8 mm

The Hydro Catchment Areas recorded 15.3 mm of average rainfall for the last week

Rmax: 74.5 mm & Rmin: 0.0 mm. 

Wind:

North-westerly and 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 Northern province, and above normal for some parts of the Southern province, driven by the warm SST’s.

Predictions

Rainfall:

During the next week (9^th – 15^th November), above 135 mm rainfall is predicted for the Western, Northern, Southern and Sabaragamuwa provinces; and heavy (≥ 125 mm) rainfall is expected for the 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 November.

Teleconnections:

La Niña is favored to continue through during the Northern Hemisphere winter (December-February) 2022-23, with a 54% chance for ENSO-neutral in February-April 2023.

MJO shall near neutral the rainfall during 9^th– 23^rd November for Sri Lanka.

Seasonal Precipitation: 

The precipitation forecast for the November-December-January 2023 season shows a higher tendency for above-normal precipitation in the north half of the country.