Climate Bulletin For Sri Lanka (4 September 2020)

 

                        Highlights                             

•   The NOAA weekly rainfall forecast predicts up to 85 mm  Galle district during 10th -16th September. 

•   Between 27th August- 2nd September: up to 100 mm of rainfall was recorded in Mannar district on 1st September.

•   From  25th- 31st August: up to 10 km/h, northwesterly winds were experienced by the Southern half 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
27th August	Up to up to 40 mm in Ampara, Polonnaruwa and Badulla districts; up to 30 mm in Batticaloa, Monaragala, Matale, Kandy and Nuwara Eliya districts; up to 15 mm in Trincoamalee districts; up to 10 mm Anuradhapura, Kurunegala, and Kegalle districts; up to 5.0 mm Puttalam, Gampaha, Matara and Hambantota districts; and up to 2.5  mm in Galle district.
28th August	Up to 20 mm in Monaragala district; up to 5 mm in Hambantota, Ampara, Badulla, Kandy, Nuwara Eliya, Ratnapura, Kegalle, Puttalam, Kurunegala and Matale districts; and up to 2.5 mm in Kalutara, Colombo, Gampaha, Anuradhapura and Polonnaruwa districts.
29th August	Up to 15 mm in Mullaitivu and Vavuniya districts; up to 10 mm in Kilinochchi district; up to 5 mm in Anuradhapura and Mannar districts; and up to 2.5 mm in Jaffna, Trincomalee, Monaragala and Badulla districts.
30th August	Up to 50 mm in Vavuniya, Anuradhapura and Polonnaruwa districts; up to 40 mm in Trincomalee district; up to 30 mm in Monaragala and Badulla districts; up to 20 mm in Batticaloa district; up to 15 mm in Hambantota, Ratnapura, Colombo, Kalutara, Kurunegala, Kegalle, Ampara and Mullaitivu districts; and up to 10 mm in Kilinichchi, Mannar, Puttalam, Matale, Gampaha, Kandy, Nuwara Eliya, Galle and Matara districts.
31st August	Up to 60 mm in Monaragala and Badulla districts; up to 50 mm in Nuwara Eliya, Kandy, Mullaitivu and Vavuniya districts; up to 40 mm in Amapara, Ratnapura and Polonnaruwa districts; up to 30 mm in Mannar, Anuradhapura, Kurunegala, Batticaloa, Matale and Hambantota districts; up to 20 mm in Kegalle and puttalam districts; up to 15 mm in Kilinochchi, Trincomalee, Gampaha, Colombo, Kalutara, Galle and Matara districts; and up to 2.5 mm in Jaffna district.
1st Sep	Up to 100 mm in Mannar district; up to 60 mm in Puttalam district; up to 40 mm in Kilinochchi. Mullaitivu and Vavuniya districts; up to 30 mm in Anuradhapura, Kurunegala, Matale, Polonnaruwa, Ampara, Batticaloa, Kalutara and Galle; up to 20 mm in Jaffna, Gampaha, Colombo, Ratnapura, Hambantota, Badulla and Monaragala districts; and up to 15 mm in Trincomalee, Kegalle, Kandy, Nuwara Eliya and Matara distrivts.
2nd Sep	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, Monaragala, 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.

Total Rainfall for the Past Week: 

The RFE 2.0 tool shows total up to 75 – 100 mm in Monaragala, Mannar, Puttalam, and Ampara districts; up to 50 – 75 mm in Badulla, Nuwara Eliya, Kandy, Matale, Polonnaruwa, Anuradhapura, Batticaloa, Vavuniya and Mullaitivu districts; up to 25 -50 mm in Kilinochchi, Trincomalee, Kurunegala, Ratnapura, Kegalle, Gampaha, Colombo, Kalutara, Galle, Matara and Hambantota districts; and up to 10 – 25 mm in Jaffna district. 

Above rainfall average up to 50 – 100 mm in Monaragala, Badulla, Ampara, Polonnaruwa, Puttalam, Mannar, Mullaitivu and Vavuniya districts; up to 25 – 50 mm in Anuradhapura, Batticaloa, Hambantota, Nuwara Eliya, Kandy, Matale and Kurunegala districts; and up to 10 – 25 mm in Ratnapura and Trincomalee districts. Below rainfall average up to 25 – 50 mm in Galle district; and up to 10 – 25 mm in Matara, Kalutara and Colombo 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 03^rd September – 09^th September: Total rainfall up to 75 mm in Galle district; up to 65 mm in Ratnapura, Matara, Kalutara and Colombo districts; up to 55 mm in Gampaha, Kegalle, Kandy, Nuwara Eliya, Monaragala and Badulla districts; up to 45 mm in Kurunegala, Matale, Ampara and Hambantota districsts; up to 35 mm in Puttalam and Batticaloa districts; up to 25 mm in Polonnaruwa, Jaffna and Kilinochchi districts; and up to 15 mm in Trincomalee, Mullaitivu, Mannar, Anuradhapura and Vavuniya districts.

From 10^th September– 16^th September: Total rainfall up to 85 mm in Galle district; up to 75 mm in Ratnapura, Kalutara, Matara and Hambantota districts; up to 65 mm in Nuwara Eliya and Kegalle districts; up to 55 mm in Kandy, Gampaha, Badulla and Monaragala districts; up to 45 mm in Ampara district; up to 35 mm in Puttalam, Kurunegala, Matale and Batticaloa districts; up to 25 mm in Polonnaruwa, Trincomalee, Kilinochchi, Mullaitivu, Vavuniya and Anuradhapura districts and up to 15 mm in Mannar district. 

IRI Model Forecast: 

From 3^rd – 8^th September: Total rainfall up to 75 mm in Colombo, Kalutara, Galle, Matale, Kandy, Kegale, Nuwara Eliya, Badulla, Mullaitivu and Trincomalee districts; and up to 50 mm in Kilinochchi, Vavuniya, Anuradhapura, Polonnaruwa, Kurunegala, Gampaha, Puttalam, Ratnapura, Matara, Hambantota, Ampara, Monaragala and Batticaloa districts.

MJO based OLR predictions:

For the next 15 days: 

MJO shall significantly enhance rainfall during 1^st -5^th September, slightly enhance during 6^th -10^th September and neutralize during 11^th – 15^th September.

Ocean State (Text Courtesy IRI)

Pacific sea state: August 26, 2020 

SSTs in the east-central and central Pacific decreased to near the La Niña threshold in late-august, 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.