Climate Bulletin For Sri Lanka (29 March 2024)

Highlights          

 • High likelihood of moderate rainfall (35mm) is predicted for the Western, Southern, Sabaragamuwa provinces and less rainfall is predicted for the rest during          27 Mar - 2 Apr.

 • On average, half of the expected rainfall was received over the country during 26 Feb - 26 Mar. Rainfall on 23 Mar was highest (169 mm) at Deniyaya (SP).

 • Winds at 850mb (1.5 km) were north easterly from 18 - 24 Mar reaching up to 5 m/s. Winds at 850mb (1.5 km) are predicted south easterly from 28 Mar - 3 Apr reaching up to 2m/s.

 •  Maximum daily temperature was in Ratnapura and Kurunegala (38.0ºC). Sea surface temperature around Sri Lanka was 0.5 - 1.5ºC above normal.

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 27^th March - 2^nd April:  

Total rainfall by Provinces

• 35 mm - Western, Southern, Sabaragamuwa
• 25 mm - Central, Uva, North Central, North Western, Eastern
• 15 mm - Northern

From 3^rd April - 9^th April:  

Total rainfall by Provinces

• 15 mm - Western, Eastern 
• ≤ 5 mm - North Western, Central, Sabaragamuwa, Southern, North Central, Northern, Uva

MJO based OLR predictions:

For the next 15 days: 

MJO shall slightly enhance the rainfall during 27^th - 31^th March, moderately enhance the rainfall during 1^st - 5^th April, and slightly enhance the rainfall during 6^th - 10^th April for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: March 25, 2024 

The SST Anomalies for the NINO3.4 region shows a +1.5 ºC on the week ending 25^th March - thus a moderate-strong El Nino is sustained. Consensus of models predict a continuation of the El Niño event until May 2024 before weakening thereafter.

Indian Sea Sate

Sea surface temperature around Sri Lanka was 0.5℃ above normal to the country in 5^th - 11^th March 2024.

Interpretation

Monitoring

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

Deniyaya. 

Daily Average Rainfall in the Met stations for previous week of (20^th March - 27^th March) = 5.4 mm

Maximum Daily Rainfall: 74.4 mm & Minimum Daily Rainfall: 0.0 mm.

Region	Average rainfall for last 8 days (mm)	Average temperature for last 8 days (ºC)
		Maximum	Minimum
Northern plains	3.8	33.8	25.4
Eastern hills	3.4	27.7	18.7
Eastern plains	7.3	32.5	25.3
Western hills	3.9	30.8	19.5
Western plains	9.1	34.1	25.6
Southern plains	4.4	33.5	25.2

Region	Average rainfall for last 8 days (mm)	Daily maximum rainfall for last 8 days (mm)	Daily minimum rainfall for last 8 days (mm)
Hydro catchment	6.8	60.0	0.0

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

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

     

Predictions

Rainfall: During the next week (27^th March - 2^nd April), moderate rainfall (35 mm) is predicted for the Western, Southern, and Sabaragamuwa provinces, and less rainfall is predicted for the rest.

Temperatures: The temperature will remain above normal for some parts of the Northern, North Central, North Western, and Eastern provinces during 28^th March - 3^rd April.

Teleconnections: MJO shall slightly enhance the rainfall during 27^th - 31^th March, moderately enhance the rainfall during 1^st - 5^th April, and slightly enhance the rainfall during 6^th - 10^th April for Sri Lanka.

Seasonal Precipitation: The precipitation forecast for the April-May-June, 2024 season shows a 40 - 50% tendency toward above normal precipitation for the country.              

Climate Bulletin For Sri Lanka (22 March 2024)

Highlights          

 • Eastern Province has no rain predicted and for other provinces the rain predicted is below 15 mm from 20 - 26 March. Dry weather conditions  are predicted for next week. 

 • On average, 1/6 of the expected rainfall was received over the country during 19 Feb - 19 Mar. Rainfall on 8 March was highest (115 mm) at Keragala (SP).

 • Winds at 850mb (1.5 km) were north easterly from 11 - 17 March reaching up to 5 m/s. Winds at 850mb (1.5 km) are predicted easterly from 21 - 27 March reaching up to 3 m/s.

 •  Maximum daily temperature was in Kurunegala (38.5ºC) & Ratnapura (37.5ºC). Sea surface temperature around Sri Lanka was 0.5 - 1.5ºC above normal.

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 20^th March - 26^th March:    

Total rainfall by Provinces

• 25 mm - Sabaragamuwa, Southern, Western 
• ≤ 15 mm - Central, Uva, Northern, North Central, North Western, Eastern

From 27^th March - 2^nd April:  

Total rainfall by Provinces

• 15 mm - North Western, Central, Sabaragamuwa, Southern, North Central, Western 
• ≤ 5 mm - Eastern, Northern, Uva

MJO based OLR predictions:

For the next 15 days: 

MJO shall moderately suppress the rainfall during 20^th - 24^th March, slightly suppress the rainfall during 25^th - 29^th March, and slightly enhance the rainfall during 30^th March - 3^rd April for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: March 19, 2024 

The SST Anomalies for the NINO3.4 region shows a +1.5 ºC on the week ending 19^th March - thus a moderate-strong El Nino is sustained. Consensus of models predict a continuation of the El Niño event until May 2024 before weakening thereafter.

Indian Sea Sate

Sea surface temperature around Sri Lanka was 0.5℃ above normal to the country in 27^th February - 4^th March 2024.

Interpretation

Monitoring

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

Daily Average Rainfall in the Met stations for previous week of (13^th March - 20^th March) = 0.4 mm

Maximum Daily Rainfall: 31.6 mm & Minimum Daily Rainfall: 0.0 mm.

Region	Average rainfall for last 8 days (mm)	Average temperature for last 8 days (ºC)
		Maximum	Minimum
Northern plains	0.0	34.4	23.8
Eastern hills	0.0	28.8	17.2
Eastern plains	0.3	33.7	23.6
Western hills	0.0	31.6	18.4
Western plains	0.8	34.1	25.7
Southern plains	2.0	34.0	24.7

Region	Average rainfall for last 8 days (mm)	Daily maximum rainfall for last 8 days (mm)	Daily minimum rainfall for last 8 days (mm)
Hydro catchment	0.8	51.5	0.0

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

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

     

Predictions

Rainfall: During the next week (20^th March - 26^th March), light showers (≤ 25mm) are predicted for the country.

Temperatures: The temperature will remain above normal for some parts of the North Western, Northern, North Central, Southern, Western, and Uva provinces during 21^st March - 27^th March.

Teleconnections: MJO shall moderately suppress the rainfall during 20^th - 24^th March, slightly suppress the rainfall during 25^th - 29^th March, and slightly enhance the rainfall during 30^th March - 3^rd April for Sri Lanka.

Seasonal Precipitation: The precipitation forecast for the April-May-June, 2024 season shows a 40 - 50% tendency toward above normal precipitation for the country.