Climate Bulletin for Sri Lanka (15 May 2020)

                                                      Highlights                             

•          The NCEP GFS weekly rainfall forecast predicts up to 75 mm of total rainfall in southwestern regions of the island during 14- 19 May.

•          Between 7 - 12 May: up to 180 mm of rainfall was recorded in Anuradhapura district on the 7^th.

•          From 6 - 12 May: up to 18 km/h, southeasterly winds were experienced by the southern regions of the island.

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

•          MJO shall enhance the rainfall in Sri Lanka in next 15 days.

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Monitoring

Rainfall

Weekly Monitoring:

Date	Rainfall
7th   May	Up to 180 mm in Anuradhapura district; up to 100 mm in Vavuniya district; up to 70 mm in Mullaitivu, Trincomalee, Mannar, Matale and Ampara districts; up to 60 mm in Kandy, Nuwara Eliya, Badulla and Monaragala districts; up to 50 mm in Kilinochchi, Puttalam, Kurunegala and Polonnaruwa districts; up to 30 mm in Ratnapura and Matara districts; and up to 20 mm in Galle, Gampaha and Kegalle districts.
8th May	Up to 60 mm in Polonnaruwa district; up to 50 mm in Kurunegala, Matale, Kandy, Ampara, Badulla and Monaragala districts; up to 30 mm in Anuradhapura, Nuwara Eliya, Kegalle and Ratnapura districts; and up to 20 mm in Vavuniya, Trincomalee, Puttalam and Batticaloa districts.
9th May	Up to 100 mm in Badulla and Monaragala districts; up to 90 mm in Kilinochchi, Mannar, Mullaitivu, Vavuniya, Anuradhapura, Polonnaruwa, Matale and Ratnapura districts; up to 50 mm in Trincomalee, Kurunegala, Kegalle, Kandy and Nuwara Eliya districts; up to 30 mm in Puttalam, Gampaha, Kalutara, Galle, Matara and Hambantota districts; and up to 20 mm in Colombo, Jaffna and Batticaloa districts.
10th May	Up to 120 mm in Kurunegala and Kegalle districts; up to 100 mm in Vavuniya district; up to 90 mm in Mullaitivu, Mannar, Anuradhapura, Kandy, Matale, Nuwara Eliya and Ratnapura districts; up to 60 mm in Polonnaruwa, Ampara, Monaragala, Gampaha and Colombo districts; up to 50 mm in Puttalam, Kalutara and Badulla districts; up to 30 mm in Kilinochchi, Trincomalee, Batticaloa and Galle districts; and up to 20 mm in Matara district.
11th May	Up to 50 mm in Anuradhapura, Trincomalee, Polonnaruwa and Batticaloa districts; up to 30 mm in Matale, Kilinochchi and Mannar districts; and up to 20 mm in Jaffna, Mullaitivu, Vavuniya, Puttalam, Kurunegala, Gampaha, Colombo, Kalutara, Gampaha, Matara, Ratnapura, Hambantota and Ampara  districts.
12th May	Up to 170 mm in Ratnapura and Monaragala districts; up to 100 mm in Kandy, Kegalle, Nuwara Eliya and Badulla districts; up to 90 mm in Matara and Hambantota districts; up to 60 mm in Kalutara district; up to 50 mm in Kurunegala, Matara, Gampaha, Colombo and Galle  districts; up to 30 mm in Ampara districts; and up to 20 mm in Jaffna, Kilinochchi, Polonnaruwa, and Batticaloa districts.
13th May	Up to 50 mm in Vavuniya, Anuradhapura, Polonnaruwa, Matale, Gampaha, Kurunegala, Ratnapura and Monaragala districts; up to 30 mm in Mullaitivu, Mannar, Kalutara, Matara, Hambantota, Ampara and Kegalle districts; up to 20 mm in most parts of the island.

Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 200-300 mm in Anuradhapura, Vavuniya, Matara, Kegalle, Ratnapura and Monaragala districts; up to 150-200 mm in Mannar, Kurunegala, Kegalle, Nuwara Eliya, Kandy and Ampara districts; up to 100-150 mm in most parts of the island. Above-average rainfall up to 200-300 mm is shown for in Anuradhapura, Ratnapura and Monaragala districts; up and to 100-200 mm in Mannar, Mullaitivu, Vavuniya, Kurunegala, Kegalle, Matara, Kandy, Nuwara Eliya, Nuwara Eliya, Kegalle, Badulla, Polonnaruwa and Ampara districts; and up to 50-100 mm in rest of the island.

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

 Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

IMD NCMWRF Forecast:
From 14^th - 20^th May: Total rainfall up to 75 mm in Kurunegala and Kegalle districts; up to 65 mm in Matara, Kandy, Gampaha and Ratnapura districts; up to 55 mm in Puttalam, Anuradhapura, Nuwara Eliya, Colombo, Matara and Galle districts; and up to 45 mm in Badulla, Monaragala and Hambantota districts.
From 21^st - 27^th May: Total rainfall up to 95 mm in Galle and Matara districts; up to 85 mm in Ratnapura district; and up to 75 mm in Badulla, Monaragala, Kurunegala, Gampaha, Colombo and Kegalle districts.

IRI Model Forecast: 
From 14^th – 19^th May: Total rainfall up to 75 mm in Gampaha, Colombo, Kalutara, Gampaha, Kegalle and Ratnapura districts; and up to 50 mm in Puttalam, Kurunegala, Kandy, Nuwara Eliya, Badulla, Matara and Hambantota districts.
MJO based OLR predictions:

For the next 15 days: 
MJO shall enhance the rainfall in Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific sea state: May 14, 2020 
SSTs in the east-central Pacific were near-average in early May, and many of the atmospheric variables were either ENSO-neutral or leaning slightly in the cool-ENSO direction. Most model forecasts favor neutral SST conditions continuing into summer, becoming below-average but not necessarily into La Nina territory by fall. The official CPC/IRI outlook is consistent with these model forecasts, calling for a likely continuation of ENSO-neutral in summer, becoming cool-neutral by fall.

Indian Ocean State
1 ⁰C above-average sea surface the temperature was observed in the seas around Sri Lanka.