Climate Bulletin for Sri Lanka ( 26 September 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 17 - 24 Sep: up to 200 mm of rainfalls were recorded in Puttalam and Gampaha districts on the 23^rd.

·  From 17 – 23 Sep: up to 36 km/h, southwesterly winds were experienced by the entire island.

·  Average sea surface temperature was observed in the seas around Sri Lanka.

 

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Monitoring

Rainfall

Weekly Monitoring: On September 17^th, Jaffna, Kilinochchi, Mullaitivu and Kurunegala districts received up to 30 mm of rainfall; and up to 20 mm in Puttalam, Mannar, Vavuniya, Kandy, and Ratnapura districts.  On the 18^th, Puttalam, Ratnapura and Monaragala districts received up to 30 mm of rainfall; Jaffna, Anuradhapura, Kurunegala, Gampaha and Colombo, districts up to 20 mm. On the 19^th, Galle district received up to 50 mm of rainfall; Ratnapura, Matara and Hambantota districts up to 30 mm; and Puttalam, Kurunegala, Gampaha, Colombo, Kalutara, Kegalle, Monaragala, and Batticaloa districts up to 20 mm. On the 20^th, Kalutara, Galle, Matara and Ratnapura districts received up to 20 mm. On the 21^sKandy and Badulla districts received up to 20 mm. On the 22^nd, Galle and Matara districts received up to 90 mm of rainfall; Badulla and Monaragala districts up to 50 mm; Gampaha, Colombo, Kalutara, Kegalle, Ratnapura, Hambantota, Nuwara Eliya, Ampara, Vavuniya and Trincomalee districts up to 30 mm; and Puttalam, Kurunegala, Matale, Kandy, and Batticaloa districts up to 20 mm. On the 23^rd, Puttalam and Gampaha districts received up to 200 mm of rainfall; Kurunegala, Colombo, Kalutara and Galle districts up to 160 mm; Kegalle, Anuradhapura, Trincomalee, Ratnapura and Matara  district up to 80 mm; Polonnaruwa, Batticaloa, Ampara, Matale, Kandy, Nuwara Eliya and Hambantota districts up to 50 mm; Mullaitivu, Vavuniya, Mannar, and Badulla districts up to 30 mm; and rest of the country up to 20 mm. On the 24^th Gampaha district received up to 100 mm of rainfall; Colombo and Kalutara districts up to 70 mm; Kegalle district up to 60 mm; Puttalam, Kurunegala, and Galle districts up to 50 mm; Kandy, Nuwara Eliya and Matara districts up to 30 mm; and Hambantota and Badulla districts up to 20 mm.

Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 300-500 mm in Gampaha district; up to 200-300 mm Puttalam, Kurunegala, Colombo, Kalutara, and Galle districts; and up to 150-200 mm in Kegalle and Ratnapura districts. Above-average rainfall up to 200-300 mm is shown for in Puttalam, Gampaha, Colombo, and Kalutara districts; up to 100-200 mm Kurunegala, Galle, and Matara districts; and up to 50-100 mm Kegalle, Kandy, Nuwara Eliya, Ratnapura and Hambantota districts.

Monthly Monitoring: During August –Above average rainfall conditions up to 360 mm were experienced by Gampaha, Colombo, Kalutara, Galle, Matara, Kegalle and Ratnapura districts; up to 240 mm in Puttalam, Kurunegala, Nuwara Eliya, Anuradhapura, Polonnaruwa, Matale, Monaragala and Hambantota; and up to 120 mm in Jaffna, Kilinochchi, Mullaitivu, Mannat, Vavuniya, Ampara, and Batticaloa. Below-average rainfall conditions up to 180 mm were experienced Trincomalee and most parts of Badulla district. The CPC Unified Precipitation Analysis tool shows up to 750 mm of total rainfall in Ratnapura district; up to 500 mm in Gampaha, Colombo, Kalutara, Galle, Matara, Kegalle, and Nuwara Eliya districts; up to 300 mm in Puttalam, Kurunegala, and Hambantota districts; and up to 200 mm in Kandy, Badulla and Monaragala districts.

Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

From 25^th Sep – 1^st Oct: Total rainfall more than  135 mm in Gampaha, Colombo, Kegalle, Ratnapura, Galle, Matara, Hambantota and Ampara districts; up to 125-135 mm in Puttalam and Nuwara Eliya districts; and up to 95-105 mm in Kurunegala, Kandy and Batticaloa districts.

From 2^nd – 8^th Oct: Total rainfall up to 135 mm in Ratnapura and Galle districts; up to 115-125 mm in Matara, Gampaha and Puttalam districts; and up to 95-105 mm in Kurunegala, Kegalle and Hambantota districts.

IMD NCMWRF Forecast:

 25^th  of Sep: Not Available

 26^th of  Sep: Not Available 

IRI Model Forecast: 

From 25^th – 30^th Sep: Total rainfall up to 150 mm is expected in Nuwara Eliya and Badulla districts; and up to 100 mm in Gampaha, Kurunegala, Kegalle, Matale, Kandy, Ampara, Monaragala, Hambantota, Ratnapura, Matara, Galle, Kalutara, and Colombo districts; and up to 75 mm in rest of the island.

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

Average sea surface temperature was observed in the seas around Sri Lanka.