Climate Bulletin For Sri Lanka (18 September 2020)

 

  Highlights                             

•  The NOAA weekly rainfall forecast predicts up to 100 mm  Galle, Kalutara, Colombo and Gampaha district during 17th -22nd September

•  Between 10th- 16th September: up to 30 mm of rainfall was recorded in Jaffna, Kilinochchi, Trincomalee, Anuradhapura, Polonnaruwa and Ratnapura districts on 13th September.

•  From  18th- 24th September: up to 15 km/h, westerly 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
10th September	Up to 20 mm in Kilinochchi, Mannar, Mullaitivu, Vavuniya, Anuradhapura, Trincomalee, Polonnaruwa and Batticaloa districts.
11th September	Up to 20 mm in Ratnapura, Kegalle, Nuwara Eliya, Badulla, Moneragala, Ampara and Batticaloa districts.
12th September	Up to 20 mm in Jaffna, Kilinochchi, Mullaitivu, Vavuniya, Mannar, Anuradhapura, Trincomalee, Polonnaruwa, Batticaloa, Matale, Ampara, Moneragala, Badulla, Nuwara Eliya, Kandy, Kegalle, Gampaha, Puttalam and Colombo districts.
13th September	Up to 30 mm in Jaffna, Kilinochchi, Trincomalee, Anuradhapura, Polonnaruwa and Ratnapura districts.
14th September	Up to 20 mm in Ratnapura district.
15th September	Up to 10 mm in Galle, Ratnapura, Kalutara, Anuradhapura, Polonnaruwa, Trincomalee and Mullaitivu districts.
16th September	Up to 10 mm in Kautara and Ratnapura districts.

Total Rainfall for the Past Week: 

The RFE 2.0 tool shows total up to 25 – 50 mm in Jaffna, Kilinochchi, Mullaitivu, Mannar, Vavuniya, Trincomalee, Anuradhapura, Polonnaruwa, Batticaloa, Ampara, Moneragala, Badulla, Nuwara Eliya, Ratnapura, Kalutara and Galle districts; and up to 10 – 25 mm in Puttalam, Kurunegala, Kegalle, Matale, Kandy, Gampaha, Colombo, Matara and Hambantota districts.   

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

 

Monthly Monitoring: 

During August – Above average rainfall conditions up to 4 mm in Monaragala, 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 17^th September – 23^rd September: Total rainfall up to 55 mm in Matara, Hambantota, Ratnapura, Colombo and Galle; up to 45 mm in Moneragala, Badulla, Kandy, Nuwara Eliya, Gampaha and Kegalle; up to 35 mm in Puttalam, Kurunegala, Matale, Jaffna and Ampara and up to 25 mm in Anuradhapura, Polonnaruwa and Batticaloa districts.  

From 24^th September– 30^th September: Total rainfall up to 85 mm in Jaffna district; up to 55 mm in Mullaitivu, Mannar, Anuradhapura and Vavuniya districts; up to 45 mm in Trincomalee, Polonnaruwa, Batticaloa, Ampara, Moneragala, Matale and Badulla districts; and up to 35 mm in Puttalam, Kunegala, Kandy, Kegalle, Nuwara Eliya, Colombo, Ratnapura, Galle, Hambantota and Matara. 

IRI Model Forecast: 

From 17^th – 22^th September: Total rainfall up to 100 mm in Galle, Kalutara, Colombo and Gampaha districts; up to 75 mm in Matara, Ratnapura, Kegalle and Kurunegala districts; up to 50 mm in Puttalam, Matale, Kandy, Nuwara Eliya, Hambantota, Moneragala and Badulla districts and up to 25 mm in Ampara, Vavuniya, Mullaitivu, Trincomalee, Kilinochchi, Vavuniya, Anuradhapura, Polonnaruwa, Mannar, Jaffna and Batticaloa districts.

MJO based OLR predictions:

For the next 15 days: 

MJO shall remain neutral during 16^th -25^th September and slightly suppressed during 26^th – 30^th September. 

Ocean State (Text Courtesy IRI)

Pacific sea state: September 9, 2020 

Equatorial Eastern Pacific SST 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.