Climate Bulletin For Sri Lanka (11 September 2020)

 

                        Highlights                             

•  The NOAA weekly rainfall forecast predicts up to 135 mm  Jaffna district during 17th -23rd September

•  Between 2nd- 8th September: up to 120 mm of rainfall was recorded in Badulla and Monaragala districts on 6th September.

•  From  2nd- 8th September: up to 15 km/h, northwesterly winds were experienced by the entire island.

•  1 0C above average sea surface temperature was observed in the seas around Sri Lanka.

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Monitoring

Rainfall

Weekly Monitoring:

Date	Rainfall
2nd September	Up to 40 mm in Mannar, Anuradhapura and Vavuniya districts; up to 30 mm in Puttalam district; up to 20 mm in Jaffna, Mullaitivu and Kilinochchi districts, up to 15 mm in Trincomalee, Ampara, Hambantota, Moneragala, Badulla, Kandy, Nuwara Eliya, Ratnapura, Kegalle, Colombo and Kalutara districts; and  up to 10 mm in Galle, Matara, Gampaha. Kurunegala, Matale, Polonnaruwa and Batticaloa districts.
3rd September	Up to 30 mm in Batticaloa district; up to 15 mm in Ampara and Polonnaruwa districts; up to 10 mm in Badulla, Matale, Anuradhapura, Trincomalee, Vavuniya and Mullaitivu districts; and up to 5 mm in Kilinochchi, Mannar, puttalam, Kurunegala, Gampaha, Kegalle, Kandy, Nuwara Eliya and Moneragala districts.
4th September	Up to  mm in 10 mm in Kilinochchi, Mullaitivu, Anuradhapura, Trincomalee, Vavuniya and Moneragala districts; up to 5 mm in Jaffna, Mannar, Puttalam, Polonnaruwa, Ampara and Badulla districts; and up to 2.5 mm in Nuwara Eliya, Kandy and Matale districts.
5th September	Up to 60 mm in Polonnaruwa, Ampara and Badulla districts; up to 50 mm in Matale and Batticaloa districts; up to 30 mm in Moneragala district; up to 20 mm in Nuwara Eliya, Kandy, Kurunegala, Anuradhapura, Puttalam and Trincomalee districts; up to 15 mm in Mannar, Vavuniya and Mullaitivu districts; up to 10 mm in Gampaha, Kegalle, Ratnapura, Kilinochchi and Jaffna districts; up to 5 mm in Colombo and Kalutara districts; and up to 2.5 mm in Galle district.
6th September	Up to 120 mm in Badulla and Moneragala districts; up to 80 mm in Nuwara Eliya district; up to  70 mm in Kandy district; up to 60 mm in Matale, Ampara and Trincomalee districts; up to 50 mm in Polonnaruwa, Puttalam and Kurunegala districts; up to 40 mm in Anuradhapura district; up to 30 mm in Galle, Kalutara, Colombo, Gampaha, Kegalle and Ratnapura districts; up to 20 mm in Batticaloa and Puttalam districts; up to 15 mm in Matara and Hambantota districts; up to 10 mm in Vavuniya and Mullaitivu districts; and up to 5 mm in Kilinochchi and Jaffna districts.
7th September	Up to 15 mm in Ampara district; up to 10 mm in Hambantota, Moneragala, Nuwara Eliya, Kandy, Badulla, Batticaloa, Kurunegala, and Matale districts; up to 5 mm in  Mullaitivu, Puttalam, Polonnaruwa, Gampaha, Kegalle, ratnapura, Anuradhapura,  Matara and Galle districts; and up to 2.5 mm in Kalutara and Jaffa districts.
8th September	Up to 60 mm in Gampaha district, up to 50 mm in Colombo, Puttalam and Kurunegala districts; up to 30 mm in Kegalle, Kalutara and Ratnapura districts; up to 20 mm in Galle and Matara districts; up to 15 mm in Hambantota, Moneragala and Ampara districts; up to 10 mm in Badulla, Batticaloa, Jaffna, Kilinichchi and Mullaitivu districts; up to 5 mm in Kandy, Nuwara Eliya, Matale, Polonnaruwa, Anuradhapura, Vavuniya, Trincomalee and Mannar districts.

Total Rainfall for the Past Week: 

The RFE 2.0 tool shows total up to 75 – 100 mm in Galle and Ratnapura districts; up to 50 - 75 mm in Matara and Colombo districts; up to 25 -75 mm in Nuwara Eliya, Kegalle and Gampaha districts; Up to 10 – 25 mm in Hambantota, Moneragala, Badulla, Ampara, Batticaloa, Polonnaruwa, Matale, Kurunegala, Anuradhapura and Puttalam districts; up to 5 -10 mm in Trincomalee and Jaffna districts.   

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

Monthly Monitoring: 

During August – Above average rainfall conditions up to 4 mm in Moneragala, Badulla and Ampara districts; and up to 3 mm in Hambantota, Ratnapura, Nuwara Eliya, Kandy, Matale, Polonnaruwa, Batticaloa, Anuradhapura, Gampaha, Kurunegala, Puttalam, Trincomalee, Vavuniya, Mullaitivu, Mannar, Kilinochchi and Jaffna districts. Below average rainfall conditions up to 3 mm in Kegalle, Colombo, Kalutara, Galle and Matara. 

 Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

From 10^th September – 10^th September: Total rainfall up to 55 mm in Jaffna, Kilinochchi and Mullaitivu districts; up to 45 mm in Trincomalee, Vavuniya, Anuradhapura, Batticaloa and Polonnaruwa districts; up to 35 mm in Mannnar, Ampara, Moneragala, Badulla, Nuwara Eliya, Kandy, Matale, Galle and Ratnapura districts; and up to 25 mm in Puttalm, Kurunegala, Kegalle, Colombo, Gampaha, Matara and Hambantota districts.  

From 17^th September– 23^rd September: Total rainfall up to 135 mm in Jaffna district; up to 95 mm in Kilinochchi and Mullaitivu districts; up to 85 mm in Mannar and Vavuniya districts; up to 65 mm in Anuradhapura and Trincomalee districts; up to 55 mm in Puttalam, Polonnaruwa, Batticaloa and Ampara districts; up to 45 mm in Kurunegala, Matale, Kandy, Nuwara Eliya, Badulla, Moneragala, Galle, Ratnapura and Matara districts; up to 35 m in Gampaha and Hambantota districts; and up to 25 mm in Kegalle district. 

IRI Model Forecast: 

From 10^th – 15^th September: Total rainfall up to 50 mm in Kalutara and Galle distritcts; and up to 25 mm in Colombo, Matale, Kandy, Kegalle, Nuwara Eliya, Badulla, Mullaitivu, Trincomalee, Kilinochchi, Vavuniya, Anuradhapura, Polonnaruwa, Kurunegala, Gampaha, Puttalam, Ratnapura, Matara, Hambantota, Ampara, Moneragala, Mannar, Jaffna and Batticaloa districts.

MJO based OLR predictions:

For the next 15 days: 

MJO shall remain neutral rainfall during 9^th -18^th September, slightly suppressed during 19^th -23^rd September.

Ocean State (Text Courtesy IRI)

Pacific sea state: September 2, 2020 

SSTs in the east-central and south eastern Pacific decreased to near the La Niña threshold in Early-September, and the atmospheric variables were either ENSO-neutral or indicative of weak La Niña conditions. The average of the forecasts of many models just short of the borderline of weak La Niña SST conditions through fall, becoming slightly weaker beginning in early winter. The official CPC/IRI outlook is somewhat similar to these model forecasts, calling for a likely continuation of ENSO-neutral in summer, with approximately equal chances of ENSO-neutral or La Niña for fall and winter. 

Indian Ocean State

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