Climate Bulletin For Sri Lanka (19 August 2022)

    

Highlights          

 • Fairly heavy rainfall is predicted for Central province and less rainfall is expected for the rest of the country during 19th - 23rd August.

 • During the last week, the average daily rainfall over Sri Lanka was 0.4 mm and hydro catchment areas have received 0.9 mm on average.

 • From 8th- 14th August, south-westerlies of 15m/s winds were experienced at 850 mb level over the island. Up to 10m/s of south-westerlies can be expected for the next week.

 •  Sea surface temperature around Sri Lanka was above 0.5℃ to the north of Sri Lanka. Land surface temperature remained near normal.

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 17^th August – 23^rd August

Total rainfall by Provinces: 

• 55 mm - Central
• 45 mm - Sabaragamuwa
• 35 mm - North-central, North-western, Western, Eastern, Uva
• 25 mm - Southern, Northern

From 24^th August – 30^th August:

Total rainfall by Provinces: 

• > 100 mm - Sabaragamuwa, Central, Southern, Western
•    95 mm - Uva, North-western
•    85 mm - North-central, Eastern
•    55 mm - Northern 

MJO based OLR predictions:

For the next 15 days: 

MJO shall near-neutral during 17^th – 26^th August and slightly enhance the rainfall during 27^th – 31^st August. 

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: August 10, 2022 

Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean in early-August. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate, a La Niña is favored to continue through 2022 with the odds for La Niña decreasing into the Northern Hemisphere late summer (July - September 2022) before increasing through the Northern Hemisphere fall and early winter 2022.

Indian Sea Sate

Sea surface temperature around Sri Lanka was above 0.5℃ to the north of Sri Lanka. 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 fairly heavy rainfall over the following area: Randenigala

Daily Average Rainfall in the Met stations for previous week of (9^th Aug - 16^th Aug) = 0.4 mm

Rmax: 15.8 mm & Rmin: 0.0 mm

Region	Average rainfall for the Last 8 days
Northern Plains	0.4 mm
Eastern	0.6 mm
Western	0.1 mm
Southern Plains	0.0 mm

The Hydro Catchment Areas recorded 0.9 mm of average rainfall for the last week

Rmax: 55.5 mm & Rmin: 0.0 mm. 

Wind:

South-westerly prevailed in the sea area and around the island last week. 

Temperature: 

The temperature anomalies were above normal for the Sabaragamuwa province, driven by the warm SST’s.

Predictions

Rainfall:

During the next week (19^th - 23^rd August) fairly heavy rainfall is predicted for Central province and less rainfall is expected for the rest of the country. 

Temperature:

The temperature remains slightly above normal in the Eastern, Northern, North-central and Uva provinces during 19^th – 24^th August. 

Teleconnections:

La Niña - La Niña is favored to continue through 2022 with the odds for La Niña decreasing into the Northern Hemisphere late summer (July-September 2022) before increasing through the Northern Hemisphere fall and early winter 2022.

MJO shall near-neutral during 17^th – 26^th August and slightly enhance the rainfall during 27^th – 31^st August. 

Seasonal Precipitation: 

The precipitation forecast for the September-October-November season shows a higher tendency for below-normal precipitation for the country.