Climate Bulletin For Sri Lanka (25 September 2020)

 

  Highlights                             

  •  The NOAA weekly rainfall forecast predicts up to 75 mm in Jaffna district during 23th - 29th September

  •  Between 16th- 22th September: up to 50 mm in Nuwara Eliya district 18th Septmenber.

• From 25th September -2th October: up to 10 km/h, North westerly winds were experienced by the southern half of the 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
16th September	Up to 10 mm in Kalutara and Ratnapura disrtricts.
17th September	Up to 30 mm in Ratnapura district.
18th September	Up to 50 mm in Nuwara Eliya district and up to 30 mm in Kandy, Badulla, Ratnapura, Kegalle, Colombo and Kalutara districts.
19th September	Up to 20 mm in Batticaloa district.
20th September	Up to 30 mm in Galle and Matara districts.
21st September	Up to 30 mm in Puttalam district..
22ndSeptember	Up to 30 mm in Puttalam district.

Total Rainfall for the Past Week: 

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

Above rainfall average up to 10 – 25 mm in Hambantota and Matara districts; Below rainfall average up to 10 – 25 mm in Galle, Ratnapura, Gampaha, Colombo, Kalutara, Kegalle, Matale, Kandy, Moneragala, Badulla, Ampara, Batticaloa, Polonnaruwa, Anuradhapura, Trincomalee, Vavuniya and Mullaitivu 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 23^th September – 29^rd September: Total rainfall up to 75 mm in Jaffna district; up to 65 mm in Kilinochchi district; up to 55 mm in Mullaitivu, Mannar and Vavuniya districts; up to 45 mm in Anuradhapura, Trincomalee, Polonnaruwa, Kegalle, Gampaha and Ratnapura districts; up to 35 mm in Galle, Matara, Badulla, Moneragala, Ampara, Batticaloa, Matale, Kandy, Nuwara Eliya, Kurunegala and Puttalam districts and up to 25 mm in Hambantota district.  

From 30^th September– 6^th October: Total rainfall up to 35 mm in Ratnapura, Kegalle, Gampaha, Colombo, Galle, Kandy and Nuwara Eliya districts; up to 25 mm in Matara, Badulla, Moneragala, Ampara, Matale, Kurunegala and Puttalam districts; and up to 15 mm in Hambantota, Batticaloa, Polonnaruwa, Anuradhapura, Trincomalee, Vavuniya, Mullaitivu, Kilinochchi and Jaffna districts.

 

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, Kilinichchi 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 suppress during 23^rd -27^th September and shall significantly suppress during 28^th September – 7^th October. 

Ocean State (Text Courtesy IRI)

Pacific sea state: September 16, 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.