Climate Bulletin for Sri Lanka ( 19 September 2019)

                                                      Highlights                                

                                 

·  The IRI weekly rainfall forecast predicts up to 75 mm of total rainfall in Kalutara and Galle districts during 18 – 23 Sep.

·  Between 10 - 15 Sep: up to 140 mm of rainfalls were recorded Hambantota district on the 14^th.

·  From 9 – 15 Sep: up to 54 km/h, westerly 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 10^th, Galle and Matara districts received up to 70 mm of rainfall; Colombo, Kalutara and Ratnapura districts received up to 30 mm; and Jaffna, Kilinochchi, Polonnaruwa, Gampaha, Kegalle, Nuwara Eliya, Badulla, Monaragala and Hambantota districts.  On the 11^th, Kalutara, Ratnapura and Galle districts received up to 70 mm of rainfall; Kurunegala, Gampaha, Colombo and Matara districts up to 60 mm; Puttalam, Hambantota, Badulla and Monaragala districts up to 50 mm; Nuwara Eliya, Ampara, Kandy and Kegalle districts up to 30 mm; and Vavuniya, Anuradhapura, Trincomalee, Batticaloa and Matale districts up to 20 mm. On the 12^th, Jaffna, Batticaloa and Ampara districts received up to 50 mm of rainfall; Kilinochchi, Mullaitivu, Badulla and Monaragala districts up to 30 mm; and Mannar, Vavuniya, Anuradhapura, Polonnaruwa, Kandy and Hambantota districts up to 20 mm. On the 13^th, Badulla and Ampara districts received up to 60 mm of rainfall; Jaffna and Mullaitivu districts up to 50 mm; Kilinochchi, Mannar, Anuradhapura, Monaragala, Matale and Kandy districts up to 30 mm; and Ratnapura and Batticaloa districts up to 20 mm. On the 14^th, Hambantota district received up to 140 mm of rainfall; Monaragala district up to 100 mm; Matara district up to 90 mm; Ratnapura, Badulla, Galle and Ampara districts up to 60 mm; Polonnaruwa, Batticaloa and Colombo districts up to 50 mm; Gampaha, Trincomalee and Nuwara Eliya districts up to 30 mm; and Mullaitivu, Anuradhapura, Puttalam, Kurunegala, Matale and Kandy districts up to 20 mm. On the 15^th Ratnapura, Gampaha, Colombo and Kalutara districts received up to 120 mm of rainfall; Mannar, Mullaitivu, Kegalle and Galle districts up to 70 mm; Vavuniya, Puttalam, Kurunegala and Matara districts up to 60 mm; Jaffna, Kilinochchi, Kandy, Nuwara Eliya, Monaragala and Hambantota districts up to 50 mm; Trincomalee, Anuradhapura and Badulla districts up to 30 mm; and Polonnaruwa, Matale and Ampara districts up to 20 mm.

Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 200-300 mm in Colombo, Kalutara, Galle, Matara and Ratnapura districts; up to 150-200 mm Gampaha, Hambantota and Monaragala districts; and up to 100-150 mm in Jaffna, Kilinochchi, Mannar, Vavuniya, Mullaitivu, Badulla and Ampara districts. Above average rainfall up to 100-200 mm is shown for in Jaffna, Kilinochchi, Mannar, Vavuniya, Gampaha, Colombo, Kalutara, Galle, Kegalle, Ratnapura, Matra, Hambantota and Monaragala districts; and up to 50-100 mm Puttalam, Kurunegala, Anuradhapura, Trincomalee, Polonnaruwa, Batticaloa, Kandy, Nuwara Eliya, Badulla and Ampara 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 18^th – 24^th Sep: Total rainfall up to 135 mm in Galle, Ratnapura and Matara districts; up to 115-125 mm in Hambantota district; and up to 85-95 mm in Gampaha, Kegalle, Badulla, Monaragala and Ampara districts.

From 25^th Sep – 1^st Oct: Total rainfall up to 105 mm in Galle, Matara and Hambantota districts; up to 85-95 mm in Gampaha, Kegalle and Ratnapura districts; and up to 65-75 mm in Kurunegala, Puttalam, Badulla and Monaragala districts.

IMD NCMWRF Forecast:

 18^th  of Sep: Not Available

 19^th of  Sep: Not Available 

IRI Model Forecast: 

From 18^th – 23^rd Sep: Total rainfall up to 75 mm is expected in Kalutara and Galle districts; and up to 50 mm in most parts of the island.

MJO based OLR predictions:

For the next 15 days: 
MJO shall not have an impact in the rainfall of Sri Lanka in the next 5 days and shall enhance in the following 10 days. 

Ocean State (Text Courtesy IRI)

Pacific sea state: September 12, 2019

SSTs in the east-central Pacific maintained ENSO-neutral levels during August. Patterns in the key atmospheric variables are also showing ENSO-neutral conditions. Model forecasts generally favor ENSO-neutral through autumn and winter, 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.