Climate Bulletin For Sri Lanka (26 April 2024)

Highlights          

 • High likelihood of moderate rainfall (25 - 50mm) is predicted for Western, Sabaragamuwa and Central provinces and less rainfall (< 20 mm) is predicted for the rest during 24 April - 1 May. 

 • On average, only 3/5 of expected rainfall was received over the Sri Lanka during 25 Mar - 23 April. Average rainfall for SL was 2.6mm and for the hydro-catchment areas was 2.3mm.

 • Winds at 850mb (1.5 km) were south easterly from 16 - 22 Apr reaching up to 3 m/s. Winds at 850mb (1.5 km) are predicted south eastely from 25 Apr - 1 May reaching up to 2 m/s.

 •  Average land surface temperature was 33.9ºC in the last week and warmer anomalies of +1-3ºC were higher in the western slopes and coast compared to the northern and southern regions. The temperature in SL has peaked for the year.

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 25^th April - 1^st May: 

Total rainfall by Provinces

• 20 - 40 mm - Western, Sabaragamuwa, Central
• 10 - 20 mm - Southern, North Central
•    < 10 mm - North Western, Northern, Eastern, Uva

MJO based OLR predictions:

For the next 15 days: 

MJO shall near neutral the rainfall during 15^th - 29^th April for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: April 22, 2024 

The SST Anomalies for the NINO3.4 region show a +1.2 ºC on the week ending 22^nd April, and a weak 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 1.0℃ above normal to the country in 2^nd - 8^th April 2024.  

Interpretation

Monitoring

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

Daily Average Rainfall in the Met stations for previous week of (17^th April - 24^th April) = 2.6 mm

Maximum Daily Rainfall: 53.7 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	0.6	35.4	26.6
Eastern hills	0.3	29.7	19.8
Eastern plains	0.0	34.7	26.0
Western hills	3.3	31.7	19.9
Western plains	9.6	33.6	26.1
Southern plains	0.0	34.3	26.3

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	2.3	49.5	0.0

Wind: South 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 North Western, Western, Sabaragamuwa, Central, North Central, and Eastern provinces of the country, driven by the warm SST’s.                                    

Predictions

Rainfall: During the next week (25^th April - 1^st May), moderate rainfall (25 - 50 mm) is predicted for the Western, Sabaragamuwa, and Central provinces and less rainfall (< 20 mm) is predicted for the rest.

Temperatures: The temperature will remain above normal for some parts of the Northern, North Central, Uva, Eastern, and North Western provinces during 25^th April – 1^st May.

Teleconnections: MJO shall near neutral the rainfall during 15^th - 29^th April for Sri Lanka.

Seasonal Precipitation: The precipitation forecast for the May-June-July, 2024 season shows a 70% or more tendency toward above normal precipitation for the country.