Climate Bulletin For Sri Lanka (12 November 2021)

Highlights          

                   

 • Heavy rainfall is predicted for North-Western, Western and Sabaragamuwa provinces from 12th Nov - 16th Nov. Greater likelihood of wet tendency is predicted for Sri Lanka from Nov to Jan.

 • Heavy rainfall was experienced in Northern, North Central, North Western, Sabaragamuwa and Western provinces with max of 300.4 mm in Anuradhapura district on 8th Nov.

 •  From 1st Nov - 8th Nov, up to 30 km/h Westerlies to Northwesterlies were experienced across the island.

 •  Sea surface temperatures were above 1.00C in the Northern and Western seas while 0.50C in the  Eastern and Southern seas around the island.

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 10^th – 16^th  November:  

Total rainfall by Provinces

• 105 mm - North Western, Sabaragamuwa, Western
•  95 mm - Central, Northern, North Central, Southern
•  75 mm - Uva
•  65 mm - Eastern

From 17^th – 23^rd  November: 

Total rainfall by Provinces:

• 105 mm - North Western, Sabaragamuwa, Western
•  95 mm - Central, Northern, North Central, Southern
•  75 mm - Eastern, Uva

MJO based OLR predictions:

For the next 15 days: 

During 10^th - 14^th November MJO shall be active giving enhanced rainfall in the North while neutral for the rest of the island. During 15^th – 19^th November MJO shall be active giving slightly suppressed rainfall and from 20^th – 24^th November giving severely suppressed rainfall.    

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: November 3, 2021 

Equatorial SSTs were near-to-below average across most of the equatorial Pacific Ocean and were above average in the western Pacific Ocean in early November. A large majority of the model forecasts predict a transition from ENSO-neutral to La Niña is favored in the next couple of months and La Niña to continue through the Northern Hemisphere fall and winter.

Indian Sea Sate

Sea surface temperatures were above 1.0⁰C in the Northern and Western seas while 0.5⁰C in the Eastern and Southern seas around the island.

Interpretation

Monitoring

Rainfall: 

During the last two weeks, there had been very heavy rainfall over the following Provinces: Northern, North Central, North Western, Sabaragamuwa and Western.

Wind: 

Westerly to North Westerly winds prevailed in the sea area and around the island last week. 

Temperature: 

The temperature anomalies were near-neutral for the entire island last week, driven by the warm SST’s.

Predictions

Rainfall:

During the next week (12^th November – 16^th November) heavy rainfall is predicted for the following provinces: North Western, Sabaragamuwa and Western.   

Temperature:

The temperature remains slightly normal during 12^th November – 20^th November for the entire island. 

Teleconnections:

La Nina -The SST forecast indicates that ENSO-neutral are present and a transition from ENSO-neutral to La Niña is favored in the next couple of months.

During 10^th November - 14^th November MJO shall be active giving enhanced rainfall in the North while neutral for the rest of the island. During 15^th November – 19^th November MJO shall be active giving slightly suppressed rainfall and from 20^th November – 24^th November giving severely suppressed rainfall.   

Seasonal Precipitation: 

The precipitation forecast for the Nov-Jan season show enhanced probabilities of above-normal precipitation over Sri Lanka.