Climate Bulletin For Sri Lanka (12 January 2024)

                   

Highlights          

 • High likelihood of  fairly heavy rainfall (50 - 100 mm) is predicted for Eastern, Southern, Uva provinces and  ≤ 45 mm rainfall is predicted for rest of the country during 10 - 16  January.

 • During the last week, average daily rainfall over Sri Lanka was 16.7 mm and hydro catchment was 12.6 mm. Maximum average daily rainfall was 39 mm on 8 Jan and 24 mm on 9 Jan. The rainfall of last week was twice as normal.

 • From 1  - 7 Dec, up to 4 m/s of north easterly winds were at 850 mb (1.5 km). During 11 - 17 Jan, up to 6 m/s of  north easterly winds are expected at 850 mb (1.5 km). 

 • Sea surface temperature around Sri Lanka was 0.25 - 1.5ºC above normal. Strong EL Nino and positive Indian ocean dipole patterns sustained. Maximum daily temperature was  in Ratnapura (34.9ºC) and Puttalam (31.4ºC) .

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 10^th January - 16^th January: 

Total rainfall by Provinces

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

MJO based OLR predictions:

For the next 15 days: 

MJO shall moderately enhance the rainfall during 10^th - 14^th January, slightly enhance the rainfall during 15^th - 19^th January and slightly suppress the rainfall during 20^th - 24^th January for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: January 8, 2024 

El Nino Mode has set in according to NOAA since 8^th of June. Equatorial sea surface temperatures (SSTs) are above average across the central and eastern Pacific Ocean early January. El Niño is expected to continue through the Northern Hemisphere winter, with a transition to ENSO-neutral favored during April-June 2024 (60% chance).

Indian Sea Sate

Sea surface temperature around Sri Lanka was 0.5℃ above normal to the Southern, Eastern, and Western half of the country in 19^th- 25^th December 2023. 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 very heavy rainfall over the following areas: Lahugala, Vakaneri Wewa, Negombo.

Daily Average Rainfall in the Met stations for previous week of (3^rd January - 10^th January) = 16.7 mm

Maximum Daily Rainfall: 172.1 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	8.5	29.7	24.5
Eastern hills	22.6	23.9	18.9
Eastern plains	33.6	29.2	24.0
Western hills	12.9	27.4	19.5
Western plains	9.0	30.8	24.4
Southern plains	24.3	29.7	23.8

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	12.6	57.0	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 the country except southern province driven by the warm SST’s.

Predictions

Rainfall: During the next week (10^th January - 16^th January), fairly heavy rainfall is predicted for the Eastern, Southern, Uva provinces and less rainfall is predicted for rest of the country.

Temperatures: The temperature will remain seasonably near normal for the country during 11^th January - 17^th January.

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

MJO shall moderately enhance the rainfall during 10^th - 14^th January, slightly enhance the rainfall during 15^th - 19^th January and slightly suppress the rainfall during 20^th- 24^th January for Sri Lanka.

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