Climate Bulletin For Sri Lanka (13 November 2020)

              Highlights                             

 •  The NOAA weekly rainfall forecast predicts Between 11th-17th Nov: very high rainfall over the Eastern and Southern Provinces the drop in rainfall over the rest of the country.

 •  Between 3rd - 9th Nov: up to 240 mm in Ratnapura and Moneragala districts on 9th  Nov.

 •  MJO shall slightly enhance the rainfall during 10^th – 14^th Nov and significantly enhance during 15^th - 24^th Nov over Sri Lanka.

 •  From  3rd - 9th Nov: up to 6 -8 km/h  northeasterly winds were experienced by the Northern of the island.

  •  0.50C above average sea surface temperature was observed in the seas around Sri Lanka which shall likely change as the La Nina sets in more fully.

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Monitoring

Rainfall

Weekly Monitoring:

Date	Daily Maximum Rainfall
3rd November	Up to 90 mm in Galle, Kalutara and Ratnapura districts.
4th November	Up to 90 mm in Anuradhapura district.
5th November	Up to 90 mm in Kegalle district.
6th November	Up to 40 mm in Puttalam and Kurunegala districts.
7th November	Up to 40 mm in Gampaha, Kalutara and Galle district.
8th November	Up to 140 mm in Gampaha district.
9th November	Up to 240 mm in Ratnapura and Moneragala districts.

Total Rainfall for the Past Week: 

The RFE 2.0 tool shows total up to 300 – 500 mm in Ratnapura and Moneragala districts; up to 200 – 300 mm in Badulla, Colombo, Kalutara, Gampaha and Matara districts; up to 150 – 200 mm in Kegalle, Galle, Nuwara Eliya, Hambantota, Mullaitivu, Vavuniya, Anuradhapura, Trincomalee districts; up to 100 – 150 mm in Kilinochchi, Puttalam, Kurunegala and Kandy districts; up to 75 – 100 mm in Matale, Mannar, Polonnaruwa and Jaffna districts; up to 50 – 75 mm in Batticaloa and Ampara districts.   

Above rainfall average up to 200 – 300 mm in Moneragala and Ratnapura districts; up to 100 – 200 mm in Hambantota, Badulla and Matara, Gampaha, Colombo, Kalutara, Mullaitivu, Vavuniya, Anuradhapura, and Trincomalee districts; up to 50 – 100 mm in Galle, Kegalle and Nuwara Eliya districts; up to 25 – 50 mm in Puttalam, Mannar, Kilinochchi and Jaffna districts; up to 10 – 25 mm in Kurunegala district; Below rainfall average up to 25 – 50 mm in Ampara, Batticaloa, Polonnaruwa, Matale and Kandy districts. 

Monthly Monitoring: 

During October – Above average rainfall conditions up to 4 mm in Vavuniya, Anuradhapura, Badulla, Ampara and Moneragala districts; up to 2 mm in Mannar, Batticaloa, Ratnapura and Hambantota districts; Below average rainfall up to 8 mm in Galle, Kalutara and Colombo district; up to 6 mm in Matara, Gampaha, Kegalle, Nuwara Eliya, Kandy, Kurunegala, Puttalam, Jaffna districts; up to 4 mm in Kilinochchi, Mullaitivu, Polonnaruwa, Matale and Trincomalee districts. 

 Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

From 11^th – 17^th November: Total rainfall up to 140 mm in East, South and Southwest of the island; up to 125 mm rainfall in Southeast and Central of the island; up to 115 mm rainfall in West and Northeast of the island and up to 105 mm in North and Northwest of the island.

From 18^th – 24^th November: Total rainfall up to 140 mm in East of the island; up to 135 mm rainfall in Central and Southwest of the island; up to 125 mm in South, Southeast and Northeast of the island; up to 105 mm in Northern and Western of the islands and up to 95 mm in Northwest of the island.  

IRI Model Forecast: 

From 24^th – 29^th September: Total rainfall up to 75 mm in Badulla district; up to 50 mm in Ampara, Moneragala, Ratnapura, Nuwara Eliya, Kandy, Matale, Polonnaruwa, Anuradhapura, Batticaloa, Trincomalee, Vavuniya, Mullaitivu, Kilinochchi and Jaffna districts; and up to 25 mm in Mannar, Puttalam, Kurunegala, Kegalle, Gampaha, Colombo, Kalutara, Galle, Matara and Hambantota districts. 

MJO based OLR predictions:

For the next 15 days: 

MJO shall slightly enhance the rainfall during 10^th – 14^th Nov and significantly enhance during 15^th - 24^th Nov over Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific sea state: November 4, 2020 

Equatorial Eastern Pacific SST reached La Niña threshold in early-November, and the atmospheric variables were either ENSO-neutral or indicative of weak La Niña conditions. 

Indian Ocean State

0.5 ⁰C above average sea surface temperature was observed in the seas around Sri Lanka.