Climate Bulletin For Sri Lanka (28 April 2023)

   

Highlights          

 • Heavy rainfall is predicted for the Sabaragamuwa, Western, Southern, Central, Uva, North Western, North Central, and Eastern provinces during 27 th Apr - 3rd May.

 • During the last week, average daily rainfall over Sri Lanka was 6.5 mm and  hydro catchment areas received 7.6 mm.

 • From 18th - 24th Apr, up to 2 m/s of Southerly winds were experienced at 850 mb level over the island. During 28th Apr - 4th May, up to 4 m/s of Westerly winds are expected.

 • Sea surface temperature around Sri Lanka was about one degree above the seasonal norm. The maximum land surface across Sri Lanka ranged from 30 - 35ºC with a drop in the hills. 

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 27^th April – 3^rd May:

Total rainfall by Provinces:    

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

From 4^th May – 10^th May:

Total rainfall by Provinces:   

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

MJO based OLR predictions:

For the next 15 days: 

MJO shall moderately enhance the rainfall during 27^th April – 11^th May for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: April 24, 2023 

Equatorial sea surface temperatures (SSTs) are near-to-above average across most of the Pacific Ocean late- April. The tropical Pacific atmosphere is consistent with ENSO-neutral conditions. A large majority of the models indicate ENSO-neutral conditions are expected to continue through the Northern Hemisphere spring, followed by a 62% chance of El Nino developing during May-July 2023.

Indian Sea Sate

Sea surface temperature around Sri Lanka was near normal to the country in 4^th – 10^th April, 2023. 

 

Interpretation

Monitoring

Rainfall:

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

         

Daily Average Rainfall in the Met stations for previous week of (18^th April – 25^th April) = 6.5 mm

Maximum Daily Rainfall: 142.0 mm & Minimum Daily Rainfall: 0.0 mm. 

Region	Average rainfall for the Last 8 days
Northern Plains	4.0 mm
Eastern	8.9 mm
Western	7.7 mm
Southern Plains	4.1 mm

The Hydro Catchment Areas recorded 7.6 mm of average rainfall for the last week.

Maximum Daily Rainfall: 52.3 mm & Minimum Daily Rainfall: 0.0 mm.

Wind: Southerly winds prevailed in the sea area and around the island last week.

Temperature: 

The temperature anomalies were above normal for some parts of the Sabaragamuwa, Southern, Western, and Central provinces and near normal for rest of the country driven by the warm SST’s.

Predictions

Rainfall:

During the next week (27^th April – 3^rd May), heavy rainfall (≥ 125 mm) is predicted for the Sabaragamuwa, Western, Southern, and Central provinces and ≥ 105 mm rainfall is predicted for the Uva, North Western, North Central, and Eastern provinces of the country.

Temperature:

The temperature will remain above normal for some parts of the Northern, North Western, North Central, Uva, Eastern, and Southern provinces during 28^th April – 4^th May.

Teleconnections:

ENSO-neutral conditions are expected to continue through the Northern Hemisphere spring, followed by a 62% chance of El Nino developing during May-July 2023.

MJO shall moderately enhance the rainfall during 27^th April – 11^th May for Sri Lanka.

Seasonal Precipitation: 

The precipitation forecast for the May-June-July, 2023 season shows near normal precipitation for the country.