Climate Bulletin for Sri Lanka ( 3 October 2019)

                                                      Highlights                                

·  The IRI weekly rainfall forecast predicts up to 150 mm of total rainfall in Nuwara Eliya and Badulla districts during 25 – 30 Sep.

·  Between 25 - 30 Sep: up to 70 mm of rainfalls were recorded in Puttalam district on the 29^th.

·  From 24 – 30 Sep: up to 18 km/h, southwesterly 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: On September 25^th, Batticaloa, Ampara and Monaragala districts received up to 60 mm of rainfall; Badulla, Nuwara Eliya and Polonnaruwa districts up to 50 mm; Matale, Kandy, Ratnapura, Galle and Matara districts up to 30 mm; and Trincomalee, Kurunegala, Kegalle, Gampaha, Colombo, Kalutara, and Hambantota districts up to 20 mm.  On the 26^th, Badulla, Monaragala and Hambantota districts received up to 50 mm of rainfall; Ratnapura and Nuwara Eliya districts up to 20 mm. On the 27^th, Anuradhapura the district received up to 30 mm of rainfall; Kurunegala and Batticaloa districts up to 20 mm; and most parts of the country up to 10 mm. On the 28^th, Kalutara, Colombo, Monaragala and Hambantota districts received up to 50 mm; Puttalam, Kurunegala, Kalutara, Galle, Ratnapura, Badulla and Ampara districts up to 30 mm; and Matale, Kegalle, Nuwara Eliya and Matara districts up to 20 mm. On the 29^th Puttalam district received up to 70 mm; Kurunegala, Anuradhapura districts up to 50 mm; Polonnaruwa and Matale districts up to 30 mm; and Mannar, Vavuniya, and Gampaha district up to 20 mm. On the 30^th, Polonnaruwa district received up to 30 mm of rainfall; and Anuradhapura, Matale and Badulla districts up to 20 mm. 

Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 75-100 mm in Puttalam Kurunegala, Badulla and Hambantota districts; up to 50-75 mm Anuradhapura, Gampaha, Colombo, Ratnapura, Gampaha, Colombo, Kandy, Matale and Monaragala districts; and up to 25-50 mm in Kegalle, Kalutara, Matara, Ampara and Batticaloa districts. Above-average rainfall up to 50-100 mm is shown for in Puttalam, Kurunegala, Badulla, Monaragala and Hambantota districts; and up to 25-50 mm Anuradhapura, Polonnaruwa, Nuwara Eliya, and Ratnapura districts. Below-average rainfall up to 10-25 mm is shown for in Jaffna, Kilinochchi, Mannar, Vavuniya, Mullaitivu and Kegalle districts.

Monthly Monitoring: During August –Above average rainfall conditions up to 450 mm were experienced by Gampaha district; up to 360 mm in Puttalam, Colombo, Kalutara, Galle, Matara, Hambantota, Monaragala and Ratnapura districts; up to 240 mm in Kurunegala, Kegalle, Jaffna, Kilinochchi, Vavuniya, Anuradhapura, Trincomalee, Polonnaruwa, Batticaloa, Badulla, Ampara, Kandy and Nuwara Eliya districts; and up to 120 mm in rest of the island. The CPC Unified Precipitation Analysis tool shows up to 750 mm of total rainfall in Gampaha, Colombo, Kalutara and Galle districts; up to 500 mm in Kurunegala, Puttalam, Kegalle, Ratnapura, Matara, Hambantota and Monaragala districts; up to 300 mm in Nuwara Eliya and Badulla districts; and up to 200 mm in Kandy, Matale, Ampara and Batticaloa districts.

Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

From 2^nd – 8^th Oct: Total rainfall more than 125 mm in Gampaha, Colombo, Ratnapura, Galle, and Matara districts; up to 95-105 mm in Hambantota district; and up to 85-95 mm in Puttalam, Kurunegala and Badulla districts.

From 9^th – 15^th Oct: Total rainfall more than 135 mm in Puttalam, Kurunegala, Gampaha, Colombo, Kegalle, Ratnapura, Galle and Matara districts; up to 95-105 mm Nuwara Eliya district; and up to 85-95 mm in Mannar, Kandy, Badulla, Monaragala and Hambantota districts.

IMD NCMWRF Forecast:

 2^nd of Oct: Not Available

 3^td of  Sep: Not Available 

IRI Model Forecast: 

From 2^nd – 7^th Sep: Total rainfall up to 150 mm is expected in Matale, Kandy, Ampara, Monaragala, Nuwara Eliya and Badulla districts; up to 100 mm in Polonnaruwa, Batticaloa, Kegalle, and Ratnapura districts; and up to 75 mm in Trincomalee, Anuradhapura, Kurunegala and Hambantota districts.

MJO based OLR predictions:

For the next 15 days: 

MJO shall enhance the rainfall of Sri Lanka. 

Ocean State (Text Courtesy IRI)

Pacific sea state: September 19, 2019

SSTs in the east-central Pacific maintained ENSO-neutral levels during September. Patterns in the key atmospheric variables are also showing ENSO-neutral conditions. Model forecasts generally favor ENSO-neutral through autumn, winter and into spring, with slightly higher chances for El Niño than La Niña. The official CPC/IRI outlook is consistent with these model forecasts.

Indian Ocean State

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