Climate Bulletin For Sri Lanka (29 April 2022)

Highlights          

                   

 • Up to 55 - 85 mm Fairly heavy  rainfall is expected  in Sabaragamuwa,  Western, Southern, Northern, North Central, North Western & Central provinces during 29th  April - 3rd May.

 • During the last week, average daily rainfall over Sri Lanka was 4.1 mm and hydro catchment areas have received  up to 6.3 mm on average.

 • From 18th - 24th April, up to 1 - 4 m/s South-westerlies & variable winds were experienced over the Island.

 • Sea surface temperature was above 0.5℃ to the north of SL. land temperatures remain around Normal, unlike the sweltering heat in Indian sub-continent.

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 27^th – 3^rd May: 

Total rainfall by Provinces:

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

From 4^th – 10^th May: 

Total rainfall by Provinces:

• 135 mm - Western
• 125 mm - Sabaragamuwa
• 115 mm - Southern
• 105 mm - Central
•  95 mm - North Western, Uva, Northern, North Central
•  65 mm - Eastern

MJO based OLR predictions:

For the next 15 days: 

MJO shall slightly enhance the rainfall during 29^th April - 6^th May and moderately enhance during 7^th – 11^th May.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: April 20, 2022 

Equatorial sea surface temperatures (SSTs) are below average across the most of the Pacific Ocean in mid-April. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate La Niña is favored to continue into the Northern Hemisphere summer.

Indian Sea Sate

Sea surface temperature was above 0.5℃ to the north of Sri Lanka. A La Niña pattern is prevalent in the Pacific Ocean but not in the Indian Ocean.  

Interpretation

Monitoring

Rainfall: 

During the last two weeks, there had been heavy rainfall over the following area: 

Galle

Daily Average Rainfall in the Met stations for previous week of (19^th - 26^th April) = 4.1 mm

Rmax: 63.9 mm & Rmin: 0.0 mm.

Region	Average rainfall for the Last 8 days
Northern Plains	2.5 mm
Eastern	0.8 mm
Western	8.2 mm
Southern Plains	5.8 mm

The Hydro Catchment Areas recorded 6.3 mm of average rainfall for the last week

Rmax: 59 mm & Rmin: 0 mm. 

Wind:

South-westerly (and variable in direction) winds prevailed in the sea area surrounding the island last week. 

Temperature: 

The temperature anomalies were near neutral for the country, driven by the warm SST’s.

Predictions

Rainfall:

During the next week (29^th April- 3^rd May) fairly heavy rainfall is predicted for the Western, Sabaragamuwa, Southern, Northern, North Central, North Western and Central provinces. 

Temperature:

The temperature remains slightly below normal in the central and Uva provinces and above normal in the northern province during 29^th April - 6^th May. 

Teleconnections:

La Nina - The SST forecast indicates that La Niña is favored to continue into the Northern Hemisphere summer (June-August 2022).

MJO shall slightly enhance the rainfall during 29^th April - 6^th May and moderately enhance during 7^th – 11^th May. 

Seasonal Precipitation: 

The precipitation forecast for the May-June-July season shows below-normal precipitation for the island, but above-normal precipitation for the northern province.