Climate Bulletin For Sri Lanka (2 February 2024)

                      

Highlights          

 • High likelihood of very heavy rainfall (> 100 mm) is predicted for Eastern province,  fairly heavy rainfall  (50 - 100 mm) is predicted for Uva, Central provinces and less rainfall (≤ 35 mm) is predicted for the rest during 31 Jan - 6 Feb.

 • Rainfall on 28  reached peak (86.5 mm) at Kurundu Oya (CP). During the last week, average daily rainfall was 2.8 mm and hydro catchment was 6.1 mm.

 • Winds at 850mb (1.5 km) were north easterly from 22 - 28 Jan reaching up to 10 m/s. Winds at 850mb (1.5 km) are predicted north easterly from 1 - 7 Feb reaching up to 6 m/s.

 • Sea surface temperature around Sri Lanka was 0.5 - 1.0ºC above normal. Strong EL Nino and positive indian ocean dipole patterns sustained. Maximum daily temperature was  in Ratnapura (35.1ºC), and Ratmalana (34.1ºC).

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 31^st January - 6^th February:    

Total rainfall by Provinces

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

MJO based OLR predictions:

For the next 15 days: 

MJO shall moderately suppress the rainfall during 31^st January - 4^th February, near normal the rainfall during 5^th - 9^th February, and moderately enhance the rainfall during 10^th - 14^th February for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: January 29, 2024 

The SST Anomalies for the NINO3.4 region shows a +1.7 ºC on the week ending 29^th Jan - thus a 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 9^th - 15^th January 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 fairly heavy rainfall over the following areas: Kurundu Oya, Poddiwela.

Daily Average Rainfall in the Met stations for previous week of (24^th January - 31^st January) = 2.8 mm

Maximum Daily Rainfall: 41.4 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	1.6	30.6	23.6
Eastern hills	5.6	24.6	17.0
Eastern plains	3.8	30.4	23.5
Western hills	6.7	28.3	17.7
Western plains	0.8	32.3	23.9
Southern plains	0.1	32.0	23.7

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	6.1	125.0	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 Central, Western, Southern, Northern, Sabaragamuwa, and North Western provinces of the country driven by the warm SST’s.

Predictions

Rainfall: During the next week (31^th January - 6^th February), heavy rainfall is predicted for the Eastern province, fairly heavy rainfall is predicted for the Uva and Central provinces, and less rainfall is predicted for rest of the country.

Temperatures: The temperature will remain above normal for some parts of the North Western, North Central provinces during 1^st - 7^th February.

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

MJO shall moderately suppress the rainfall during 31^st January - 4^th February, near normal the rainfall during 5^th - 9^th February, and moderately enhance the rainfall during 10^th - 14^th February for Sri Lanka.

Seasonal Precipitation: The precipitation forecast for the February-March-April, 2024 season shows near normal precipitation.