Climate Bulletin For Sri Lanka (26 July 2024)

  

Highlights   

       

 • During 24 - 30 July, high likelihood of fairly heavy rainfall (50 - 100 mm) is predicted for the Sabaragamuwa, Western and Southern provinces ; moderate rainfall (25 - 50 mm) is predicted for the Uva, Central and North Western provinces and below 15 mm rainfall is predicted for the rest.

 • On average, 1 mm was received in SL and rainfall was concentrated in the   Western plains (2.6 mm) and hills (2 mm) for last 8 days. On average, 7.5 mm was received in the hydro catchments in SL; Laxapana (Nuwara Eliya District) received the highest rainfall (43.4 mm) for last 8 days. Highest daily rainfall was in Deraniyagala (Kegalle District) on 23 July (54.5 mm).

 • From 17 Jul - 23 Jul, winds at 850mb (1.5km) were  westerly and north-westerly, reaching up to 20 m/s. From 26 Jul - 1 Aug, winds are predicted to be north-westerly, reaching up to 10 m/s. 

 • Average land surface temperature was 31ºC in the last week with near neutral anomalies from seasonal average of -1- +1 ºC. Eastern plains was warmest followed by Southern and Northern plains. Sea surface temperature around Sri Lanka was 0.5 - 1.5ºC above average.

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 24^th July - 30^th July:  

Total rainfall by Provinces

• 95 mm - Southern, Western
• 55 mm - Sabaragamuwa
• 45 mm - Central, Uva, North Western
• ≤ 15 mm - Northern, Eastern, North Central

From 31^st July - 6^th August:  

Total rainfall by Provinces

• 105 mm - Southern
•  95 mm - Western
•  55 mm - Sabaragamuwa 
•  45 mm - Central, Uva, North Western
• ≤ 15 mm - Northern, North Central, Eastern

MJO based OLR predictions:

For the next 15 days: 

MJO shall be near neutral for the rainfall during 24 July-7 August for Sri Lanka.

     

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: July 22, 2024 

ENSO-neutral conditions are present. Equatorial sea surface temperatures (SSTs) are above average in the western and west-central Pacific, near average in the east-central Pacific, and below average in the eastern Pacific Ocean. ENSO-neutral is expected to continue for the next several months, with La Niña favored to develop during August-October (70% chance) and persist into the Northern Hemisphere winter 2024-25 (79% chance during November-January).

Indian Sea Sate

Sea surface temperature around Sri Lanka was 1.0℃ above average from 2 July to 8 July 2024.

Interpretation

Monitoring

Rainfall: :During the last two weeks, there has been fairly heavy rainfall over the following area: Laxapana (Nuwara Eliya District)

Daily Average Rainfall in the Met stations for the previous week of (19 July - 24 July) = 1 mm

Maximum Daily Rainfall: 21.5 mm & Minimum Daily Rainfall: 0.0 mm.

Region	Average rainfall for 19 – 24 Jul (mm)	Average temperature for 19 – 24 Jul (ºC)
		Maximum	Minimum
Northern plains	0.0	33.8	26.8
Eastern hills	0.0	29.6	19.8
Eastern plains	0.0	36.0	25.8
Western hills	2.1	27.2	20.4
Western plains	2.6	31.5	26.0
Southern plains	0.1	34.0	25.7

Region	Average rainfall for 19 – 24 Jul (mm)	Daily maximum rainfall for 19 – 24 Jul (mm)	Daily minimum rainfall for 19 – 24 Jul (mm)
All SL	0.9	21.5	0.0
Hydro catchment	7.5	43.4	0.0

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

Temperatures: The temperature anomalies were near neutral for Sri Lanka driven by the warm SSTs.

                                                    

Predictions

Rainfall: During the next week (24 July - 30 July), fairly heavy rainfall (50 - 100 mm) is predicted for the Sabaragamuwa, Western and Southern provinces and moderate rainfall (25 - 50 mm) is predicted for the Uva, Central and North Western provinces and light showers are predicted for the rest.

Temperatures: The temperature will remain above normal for the Northern, Eastern, North Central, and Uva provinces during 26 July - 2 August.

Teleconnections: MJO shall be near neutral for the rainfall during 24 July-7 August for Sri Lanka.

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