Climate Bulletin For Sri Lanka (23 February 2024)

                         

Highlights          

 • High likelihood of   moderate rainfall (25 - 50 mm) is predicted for the Eastern, Northern, Southern, Uva provinces and less rainfall (≤ 15 mm) is predicted for the rest during 21 - 27 Feb.

 • Rainfall on 15 Feb was highest (43 mm) at Bowatenna (CP). During the last week, average daily rainfall was 0.6 mm and hydro catchment was 2.1 mm.

 • Winds at 850mb (1.5 km) were north easterly from 12 - 18 Feb reaching up to 10 m/s. Winds at 850mb (1.5 km) are predicted north easterly from 22 - 28 Feb reaching up to 4 m/s.

 • Sea surface temperature around Sri Lanka was 0.5 - 1.5ºC above normal. Strong EL Nino and positive indian ocean dipole patterns sustained. Maximum daily temperature was in Katunayake (37.2ºC) and Kurunegala (36.4ºC).

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 21st February - 27th February:  

Total rainfall by Provinces 

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

From 28th February - 5th March:  

Total rainfall by Provinces

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

MJO based OLR predictions:

For the next 15 days: 

MJO shall near neutral the rainfall during 21^st - 25^th February, slightly enhance the rainfall during 26^th February - 1^st March, and moderately enhance the rainfall during 2^nd - 6^th March for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: February 19, 2024 

The SST Anomalies for the NINO3.4 region shows a +1.7 ºC on the week ending 19^th Feb - 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 1.0℃ above normal to the country in 30^th January - 5^th February 2024. A positive Dipole Mode has set in across the Indian Ocean since 8^th of June.

Interpretation

Monitoring

Rainfall: : During the last two weeks, there had been moderate rainfall over the following areas: Bowatenna, Nuwara Eliya.

Daily Average Rainfall in the Met stations for previous week of (13^th February - 20^th February) = 0.6 mm

Maximum Daily Rainfall: 10.2 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	32.2	24.2
Eastern hills	0.7	25.9	17.8
Eastern plains	1.0	31.4	24.8
Western hills	1.1	28.3	18.9
Western plains	0.5	33.9	24.9
Southern plains	0.9	33.4	24.6

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	2.1	43.2	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 Southern, Western, Sabaragamuwa, North Western, Eastern, Central, and Northern provinces of the country driven by the warm SST’s.         

Predictions

Rainfall: During the next week (21^st February - 27^th February), moderate rainfall is predicted for the Eastern, Northern, Southern, and Uva provinces and less rainfall is predicted for the rest.

Temperatures: The temperature will remain above normal for some parts of the North Western, Western, Southern, Northern, North Central, Uva, and Eastern provinces during 22^nd - 28^th February.

Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8^th of June.

MJO shall near neutral the rainfall during 21^st - 25^th February, slightly enhance the rainfall during 26^th February - 1^st March, and moderately enhance the rainfall during 2^nd - 6^th March for Sri Lanka.

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