Climate Bulletin For Sri Lanka (7 August 2020)

 

                        Highlights                             

•   The NOAA weekly rainfall forecast predicts up to 75 mm in Gampaha, Colombo, Kalutara, Galle, Ratnapura and Kegalle districts during 5th -10th August. 

  •   Between 29th July - 4th August: up to 30 mm of rainfall was recorded in Jaffna district on 29th July

•  From 28th July - 3rd August: up to 15 km/h, northwesterly winds were experienced by the entire island.

•  1.5 0C above average sea surface temperature was observed in the seas around Sri Lanka.

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Monitoring

Rainfall

Weekly Monitoring:

Date	Rainfall
29th July	Up to 30 mm in Jaffna districts; and up to 10 mm in Anuradhapura and Trincomalee districts.
30th July	Up to 10 mm in Gampaha, Colombo, Kegalle, Ratnapura, Kandy, Nuwara Eliya, Badulla, Monaragala and Hambantota districts.
31st July	Up to 10 mm in Kegalle district.
1st August	Up to 15 mm in Galle district; and up to 10 mm in Gampaha, Colombo, Kalutara, Matara, Ratnapura, Kegalle, Batticaloa, Polonnaruwa, Matale, Kurunegala and Ampara districts.
2nd August	Up to 15 mm in Gampaha, Kalutara and Galle districts; and up to 10 mm in Puttalam, Kurunegala, Colombo, Kegalle, Ratnapura, and Nuwara Eliya districts.
3rd August	Up to 20 mm in Galle and Matara districts; up to 15 mm in Kalutara, Ratnapura, Hambantota districts; and up to 10 mm in Kandy, Nuwara Eliya, Badulla, Monaragala, Matale, Ampara, Polonnaruwa and Batticaloa districts.
4th August	Up to 15 mm in Anuradhapura, Polonnaruwa and Trincomalee districts; and up to 10 mm in Galle, Matara, Hambantota, Monaragala, Badulla, Nuwara Eliya, Ampara, Batticaloa, Gampaha, Kegalle, Kandy, Matale, Kurunegala, Puttalam, Mannar, Vavuniya, Kilinochchi, Mullaitivu, Jaffna and Ratnapura districts.

Total Rainfall for the Past Week: 

The RFE 2.0 tool shows total up to 10– 25 mm in Anuradhapura, Trincomalee, Jaffna, Polonnauwa, Matale, Kurunegala, Puttalam, Colombo, Gampaha, Kalutara, Galle, Matara, Hambantota, Ratnapura, Ampara, Monaragala, Badulla, Nuwara Eliya, Kandy, Kegalle and Batticaloa districts; up to 5 – 10 mm in Kilinochchi, Mullaitivu, Vavuniya and Mannar, districts.

Above rainfall average up to 25-50 mm in Jaffna district. Below rainfall average up to 10-25 mm in Ratnapura district.

 

Monthly Monitoring: 

During July – Above average rainfall conditions up to 10 mm were experienced by Vavuniya, Polonnaruwa, Matale and Anuradhapura districts; up to 6 mm in Jaffna, Mannar, Mullaitivu, Kilinochchi, Puttalam, Trincomalee, Kurunegala, Kandy, Badulla, Ratnapura, Nuwara Eliya, Ampara, Monaragala and Hambantota districts and up to 4 mm in Gampaha, Colombo, Kalutara, Galle, Matara, Kegalle and Batticaloa districts.

 Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

From 6^th August – 12^th August: Total rainfall up to 55 mm in Kalutara, Kegalle, Ratnapura, Galle and Matara, districts; up to 45 mm in Colombo, Gampaha, Kandy, Hambantota, Nuwara Eliya, Vavuniya and Mullaitivu districts; up to 35 mm in Matale, Kurunegala, Badulla, Puttalam, Monaragala, Trincomalee and Anuradhapura districts; and up to 25 mm in Mannar, Batticaloa, Polonnaruwa, Ampara and districts.

From 13^th August – 19^th August: Total rainfall up to 45 mm in Kalutara, Kegalle, Ratnapura, Gampaha and Colombo districts; up to 35 mm in Kurunegala, Anuradhapura, Matale, Kandy, Nuwara Eliya, Galle, Matara and Hambantota districts; up to 25 mm in Puttalam, Vavuniya, Mullaitivu, Trincomalee, Polonnaruwa, Ampara, Badulla and Monaragala districts. 

IRI Model Forecast: 

From 5^th August – 10^st August: Total rainfall up to 75 mm in Gampaha, Colombo, Kalutara, Galle, Ratnapura and Kegalle districts; up to 50 mm in Puttalam, Kurunegala, Kandy, Matara, Hambantota, Jaffna, Kilinochchi, Mullaitivu and Nuwara Eliya.

MJO based OLR predictions:

For the next 15 days: 

MJO shall enhance rainfall during 5 - 9 August, neutral during 10-14 August and shall suppressed during 15 – 19 August.

Ocean State (Text Courtesy IRI)

Pacific sea state: July 29, 2020 

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

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