Climate Bulletin For Sri Lanka (28 June 2024)

Highlights          

 • During 24 - 30 Jun, high likelihood of moderate rainfall (25 - 50 mm) is predicted for the Sabaragamuwa, Western, Southern, North Western provinces; light to moderate rainfall (12.5 -25 mm) is predicted for the Southern province; below 5 mm rainfall is predicted for the rest.

 • On average, 4.3 mm was received in SL and rainfall was concentrated in the Western plains (11.6 mm) and hills (10.5 mm). On average, 17.0 mm was received in the hydro catchments; Canyon received the highest rainfall (91.3 mm). Highest daily rainfall was in Moraliya Oya (Kegalle) on 24 June. (95.7 mm).

 • From 15 - 21 Jun, winds at 850mb (1.5km) westerly, reaching up to 15 m/s. From 27 Jun - 3 Jul, winds are predicted to be north westerly, reaching up to 10 m/s.  

 • Average land surface temperature was 31ºC in the last week with warmer anomalies from seasonal average of 1- 3ºC. Eastern plain was warmest followed by Northern and Southern plains. Sea surface temperature around Sri Lanka was 0.25- 1.5ºC above average.

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 24^th June - 30^th June:  

Total rainfall by Provinces

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

From 1^st July - 7^th July:  

Total rainfall by Provinces

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

MJO based OLR predictions:

For the next 15 days: 

MJO shall be near neutral the rainfall during 24 – 28 June and slightly enhance the rainfall during 29 June - 8 July for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: June 24, 2024 

ENSO-neutral conditions are present. Equatorial sea surface temperatures (SSTs) are above average in the west-central Pacific Ocean, near-average in the east-central Pacific Ocean, and below-average in the far eastern Pacific Ocean in late June. La Niña is favored to develop during July-September (65% chance) and persist into the Northern Hemisphere winter 2024-25 (85% chance during November-January).

Indian Sea Sate

Sea surface temperature around Sri Lanka was 1.0℃ above average on the Northern, Eastern and Southern sides of the country on 4- 10 June 2024.

Interpretation

Monitoring

Rainfall: :During the last two weeks, there has been fairly heavy rainfall over the following areas: Moraliya Oya (Kegalle)

Daily Average Rainfall in the Met stations for the previous week of (19^th June - 26^th June) = 4.3 mm

Maximum Daily Rainfall: 49.1 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	0.4	32.9	26.6
Eastern hills	1.6	28.3	20.4
Eastern plains	0.1	35.1	26.4
Western hills	10.5	26.2	20.6
Western plains	11.6	30.8	25.5
Southern plains	1.6	32.4	25.5

Region	Average rainfall for last 8 days (mm)	Daily maximum rainfall for last 8 days (mm)	Daily minimum rainfall for last 8 days (mm)
All SL	4.3	49.1	0.0
Hydro catchment	17.0	91.3	0.0

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

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

                                                    

Predictions

Rainfall: During the next week (24^th June - 30^th June), moderate rainfall (25 - 50 mm) is predicted for the Sabaragamuwa, Western, Southern, and North Western provinces and light to moderate rainfall (12.5 - 25 mm) is predicted for the Southern province and less rainfall is predicted for the rest.

Temperatures: The temperature will remain above normal for the Northern, Eastern, North Central and Uva provinces during 27 June - 3 July.

Teleconnections: MJO shall near neutral the rainfall during 24- 28 June and slightly enhance the rainfall during 29 June - 8 July for Sri Lanka.           

Seasonal Precipitation: The precipitation forecast for the July-August-September, 2024 season shows a 45 - 50% or more tendency toward above-normal precipitation for the country.    

Climate Bulletin For Sri Lanka (21 June 2024)

Highlights          

 • During 18 - 24 June, high likelihood of fairly heavy rainfall (50 - 100 mm) is predicted for the North Western, Western, Sabaragamuwa provinces; moderate rainfall (25 - 50 mm) is predicted for the Southern, Central provinces and less rainfall is predicted for the rest.

 • On average, 1.2 mm was received in SL and rainfall was concentrated in the Western plains (3.3 mm) and hills (1.8 mm). Daily average rainfall in  this week (1.2 mm) was lower than previous week (2.4 mm). Highest daily rainfall was in Guruluwana (Ratnapura) on 18 June. (95.4 mm).

 • From 9 - 15 June, winds at 850mb (1.5km) north westerly, reaching up to 15 m/s. From 19 - 25 June, winds are predicted to be north westerly, reaching up to 20 m/s.  

 • Average land surface temperature was 32.2ºC in the last week with warmer anomalies from seasonal average of +1ºC - 3ºC. Eastern plain was more warmest followed by Northern and Southern plains. Sea surface temperature around Sri Lanka was 0.25 - 1.5ºC above average.

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 18^th June - 24^th June:  

Total rainfall by Provinces

• 65 mm - North Western
• 55 mm - Western, Sabaragamuwa 
• 45 mm - Southern
• 35 mm - Central
• ≤ 5 mm - North Central, Northern, Eastern, Uva

From 25^th June - 1^st July:  

Total rainfall by Provinces

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

MJO based OLR predictions:

For the next 15 days: 

MJO shall near neutral the rainfall during 18^th - 22^nd June, slightly enhance the rainfall during 23^rd - 27^th June, and moderately enhance the rainfall during 28^th June - 2^nd July for Sri Lanka. 

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: June 17, 2024 

ENSO-neutral conditions are present. Equatorial sea surface temperatures (SSTs) are above average in the west-central Pacific Ocean, near average in the east-central Pacific Ocean, and below-average in the far eastern Pacific Ocean mid-June. La Niña is favored to develop during July-September (65% chance) and persist into the Northern Hemisphere winter 2024-25 (85% chance during November-January). 

Indian Sea Sate

Sea surface temperature around Sri Lanka was 0.5℃ above average to the Northern and Eastern half of the country in 28^th May - 3^rd June 2024.

Interpretation

Monitoring

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

Guruluwana (Ratnapura)

Daily Average Rainfall in the Met stations for previous week of (11^th June - 18^th June) = 1.2 mm

Maximum Daily Rainfall: 37.0 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	0.7	33.1	26.9
Eastern hills	0.9	29.8	18.4
Eastern plains	0.0	35.0	25.5
Western hills	1.8	27.8	20.1
Western plains	3.3	31.6	26.3
Southern plains	0.1	32.2	25.9

Region	Average rainfall for last 8 days (mm)	Daily maximum rainfall for last 8 days (mm)	Daily minimum rainfall for last 8 days (mm)
All SL	1.2	37.0	0.0
Hydro catchment	2.5	37.5	0.0

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

Temperatures: The temperature anomalies were above normal for some parts of the Central and Uva provinces and below normal for some parts of the Eastern province driven by the warm SST’s.

                                                    

Predictions

Rainfall: During the next week (18^th June - 24^th June), fairly heavy rainfall (50 - 100 mm) is predicted for the North Western, Western, and Sabaragamuwa provinces, moderate rainfall (25 - 50 mm) is predicted for the Southern and Central provinces and less rainfall is predicted for the rest.

Temperatures: The temperature will remain above normal for the Northern, Eastern, North Central and Uva provinces during 19^th June - 25^th June.

Teleconnections: MJO shall near neutral the rainfall during 18^th - 22^nd June, slightly enhance the rainfall during 23^rd - 27^th June, and moderately enhance the rainfall during 28^th June - 2^nd July for Sri Lanka.             

Seasonal Precipitation: The precipitation forecast for the July-August-September, 2024 season shows a 40 - 50% or more tendency toward above normal precipitation for the country.