Climate Bulletin For Sri Lanka (5 May 2023)

    

Highlights          

 • Heavy rainfall (> 100 mm) is predicted for the Sabaragamuwa, and Western provinces and fairly heavy rainfall (75mm - 100mm) is predicted for rest of the country during 3rd - 9th May.

 • During the last week, average daily rainfall over Sri Lanka was 13.2 mm and  hydro catchment areas received 7.8 mm. Highest average rainfall 16.0 mm/day was received to Western plains.

 • From 24th - 30th Apr, up to 4 m/s of Easterly winds were experienced at 850 mb level (1.5 km). During 5th - 11th May, up to 10 m/s of Westerly winds are expected at 850 mb level (1.5 km).

 • Sea surface temperature around Sri Lanka was about 1 - 1.5 degree above the seasonal norm. Land surface temperature remained near normal. 

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 3^rd May – 9^th May:

Total rainfall by Provinces:    

• 105 mm - Sabaragamuwa, Western
• 95 mm - Southern, Central, North Western
• 85 mm - Uva, North Central, Eastern
• 75 mm - Northern

From 11^th May – 16^th May:

Total rainfall by Provinces:   

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

MJO based OLR predictions:

For the next 15 days: 

MJO shall moderately enhance the rainfall during 3^rd – 6^th May, slightly enhance the rainfall during 7^th – 11^th May, and slightly suppress the rainfall during 12^th – 16^th May for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: May 1, 2023 

Equatorial sea surface temperatures (SSTs) are near-to-above average across most of the Pacific Ocean early- May. 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, Kilinochchi
         

Region	Average rainfall for the Last 8 days
Northern Plains	12.5 mm
Eastern	11.7 mm
Western	16.0 mm
Southern Plains	8.8 mm

Wind: Easterly winds prevailed in the sea area and around the island last week.
Temperature: 
The temperature anomalies were near normal for the whole country driven by the warm SST’s.

Daily Average Rainfall in the Met stations for previous week of (26^th April – 3^rd May) = 13.2 mm 

Maximum Daily Rainfall: 87.7 mm & Minimum Daily Rainfall: 0.0 mm. 

The Hydro Catchment Areas recorded 7.8 mm of average rainfall for the last week.

Maximum Daily Rainfall: 53.0 mm & Minimum Daily Rainfall: 0.0 mm.

Predictions

Rainfall:

During the next week (3^rd May – 9^th May), heavy rainfall (> 100 mm) is predicted for the Sabaragamuwa, and Western provinces and fairly heavy rainfall (≥ 75 mm) is predicted for rest of the country.

Temperature:

The temperature will remain above normal for some parts of the Eastern province and below normal for some parts of the Central, Uva, and Sabaragamuwa provinces during 5^th May – 11^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 3^rd – 6^th May, slightly enhance the rainfall during 7^th – 11^th May, and slightly suppress the rainfall during 12^th – 16^th May for Sri Lanka.

Seasonal Precipitation: 

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