Climate Bulletin For Sri Lanka (16 October 2020)

              Highlights                             

  •  The NOAA weekly rainfall forecast predicts up to 75 mm in Ratnapura, Colombo, Gampaha and Kegalle districts during 22nd -28th Oct. 

  •  Between 8th - 14th Oct up to 90 mm in Vavuniya and Anuradhapura districts.

• From 7th - 13th Oct:up to 15 km/h  northwesterly winds were experienced by the entire island.

• 0.5 0C above average sea surface temperature was observed in the seas around Sri Lanka

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Monitoring

Rainfall

Weekly Monitoring:

Date	Rainfall
8th October	Up to 90 mm in Vavuniya and Anuradhapura districts.
9th October	Up to 70 mm in Moneragala and Ampara districts.
10th October	Up to 30 mm in Nuwara Eliya, Ratnapura, Kegalle and Kandy districts.
11th October	Up to 20 mm in Jaffna, Gampaha, Colombo, Ratnapura, Kegalle, Nuwara Eliya and Kandy districts.
12th October	Up to 10 mm in Galle, Matara, Jaffna, Kilinochchi, Mullaitivu and Vavuniya districts.
13th October	Up to 15 mm in Galle, Matara and Hambantota districts.
14th October	Up to 20 mm in Nuwara Eliya and Kandy districts.

Total Rainfall for the Past Week: 

The RFE 2.0 tool shows total up to 50 – 70 mm in Moneragala, Nuwara Eliya, Kegalle, Kandy, Kalutara, Anuradhapura, Vavuniya and Mullaitivu districts; up to 25 – 50 mm in Hambantota, Ampara, Badulla, Ratnapura, Gampaha, Colombo, Galle, Mannar, Trincomalee and Matara districts; and up to 10 -25 mm in Jaffna, Kilinochchi, Puttalam, Krunegala, Batticaloa, Polonnaruwa and Matale districts.

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

 

Monthly Monitoring: 

During September – Above average rainfall conditions up to 12 mm in Badulla and Moneragala districts; up to 8 mm in Mannar district; up to 5 mm in Ampara, Polonnaruwa, Batticaloa, Trincomalee, Anuradhapura, Kilinochchi, Mullaitivu, Vavuniya and Jaffna districts; up to 4 mm in Puttalam, Kurunegala, Gampaha, Matale, Kandy, Nuwara Eliya, Ratnapura and Hambantota districts; and up to 2 mm in Colombo, Kalutara, Galle, Matara and Kegalle districts. 

 Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

From 15^th October – 21^th October: Total rainfall up to 65 mm in Ratnapura, Kegalle and Gampaha districts; up to 55 mm in Galle, Kurunegala and Puttalam districts; up to 45 mm in Matara, Nuwara Eliya, Kandy districts; up to 35 mm in Hambantota, Badulla and Moneragala districts; up to 25 mm in Matale district; and up to 15 mm in Polonnaruwa and Ampara districts.  

From 22^nd October – 28^th October: Total rainfall up to 75 mm in Ratnapura, Colombo, Gampaha and Kegalle districts; up to 65 mm in Galle, Kurunegala and Puttalam districts; up to 45 mm in Matara, Hambantota, Nuwara Eliya, Kandy, Matale districts; up to 35 mm Monaragala and Badulla districts; up to 25 mm in Ampara and Polonnaruwa districts; and up to 15 mm in Batticaloa and Anuradhapura 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, Kilinochchi 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 significantly suppress during 14^th-18^th Oct and shall severely suppress during 19^th–23^rd Oct.

Ocean State (Text Courtesy IRI)

Pacific sea state: October 7, 2020 

Equatorial Eastern Pacific SST decreased to near the La Niña threshold in early -October, 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

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