Climate Bulletin For Sri Lanka (24 November 2023)

            

Highlights          

 • High probability of heavy rainfall ( > 130 mm) is predicted for Sabaragamuwa, Uva provinces and fairly heavy rainfall is predicted for Central,  Southern, Western provinces during  23 - 29 Nov

 • During the last week, average daily rainfall over Sri Lanka was 16.3 mm and hydro catchment was 22.8 mm. Extreme rainfall (> 150 mm/day) was in Nuwara Eliya and Jaffna. The rainfall of last week was twice as normal.

 • From 13 - 19 Nov, up to 3 m/s of south westerly winds were at 850 mb (1.5 km). During 23 - 29 Nov, up to 5 m/s of north easterly winds are expected at 850 mb (1.5 km). Wind direction will predominantly transition from SW to from NE.

 • Sea surface temperature around Sri Lanka was 0.5 - 1.5ºC above normal. From 16 - 22 Nov, maximum daily temperature was recorded in Ratnapura  (35.0ºC) and Moneragala (33.4ºC).

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Predictions

Rainfall

7-day prediction: 
NOAA NCEP models: 

From 23^rd November - 29^th November:  

Total rainfall by Provinces

• > 130 mm - Sabaragamuwa, Uva
• 70 - 130 mm - Central
• 40 - 70 mm - Southern, Western
• 20 - 40 mm - Eastern, North Central, North Western, Northern

MJO based OLR predictions:

For the next 15 days: 

MJO shall significantly enhance the rainfall during 22^nd November - 1^st December and moderately enhance the rainfall during 2^nd - 6^th December for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: November 20, 2023 

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 mid-November. El Niño is anticipated to continue through the Northern Hemisphere spring (with a 62% chance during April-June 2024).

Indian Sea Sate

Sea surface temperature around Sri Lanka was 0.5 ℃ above normal to the country in 31^st October - 6^th November, 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: Nuwara Eliya, Jaffna

Daily Average Rainfall in the Met stations for previous week of (16^th November - 22^nd November) = 16.3 mm

Maximum Daily Rainfall: 96.3 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	14.8	30.5	24.7
Eastern hills	15.3	26.8	19.0
Eastern plains	14.9	31.6	24.6
Western hills	25.3	28.4	19.7
Western plains	20.2	31.4	24.7
Southern plains	6.6	31.5	24.9

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	22.8	185.5	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 Sabaragamuwa, Central, Western, Uva, and Eastern provinces of the country driven by the warm SST’s.

Predictions

Rainfall: During the next week (23^rd November - 29^th November), heavy rainfall is predicted for the Sabaragamuwa, Uva provinces and fairly heavy rainfall is predicted for the Central, Southern, and Western provinces, and less rainfall is predicted for rest of the country.

Temperatures: The temperature will remain seasonably near normal for the country during 23^rd November - 29^th November.

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

MJO shall significantly enhance the rainfall during 22^nd November - 1^st December and moderately        enhance the rainfall during 2^nd - 6^th December for Sri Lanka.

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