Climate Bulletin for Sri Lanka (7 May 2020)

                                                      Highlights                             

•          The NOAA weekly rainfall forecast predicts up to 100 mm of total rainfall in Badulla, Nuwara Eliya and Kandy districts during 4- 9 May.

•          Between 29 Apr - 5 May: up to 140 mm of rainfall was recorded in Anuradhapura district on the 30^th

•          From 28 Apr -  4 May: up to 18 km/h, northwesterly winds were experienced by the southern regions of the island.

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

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Monitoring

Rainfall

Weekly Monitoring:

Date	Rainfall
29th April	Up to 70 mm in Ampara, Badulla and Monaragala districts; up to 60 mm in Matale, Kandy and Ratnapura districts; up to 30 mm in Kegalle and Nuwara Eliya districts; and up to 20 mm in Puttalam, Kalutara, Galle, Polonnaruwa and Batticaloa districts.
30th   April	Up to 140 mm in Anuradhapura district; up to 70 mm in Vavuniya district; up to 60 mm in Ratnapura, Galle, Monaragala and Hambantota districts; up to 50 mm in Mullaitivu, Mannar, Kalutara, Polonnaruwa and Badulla districts; up to 30 mm in Kilinochchi, Trincomalee, Kegalle, Kandy and Nuwara Eliya districts; and up to 20 mm in Puttalam, Matale, Gampaha and Colombo districts.
1st May	Up to 120 mm in Anuradhapura district; up to 70 mm in Trincomalee and Polonnaruwa districts; up to 50 mm in Vavuniya, Monaragala and Hambantota districts; up to 30 mm in Ratnapura and Badulla districts; and up to 20 mm in Mullaitivu and Mannar districts.
2nd May	Up to 20 mm in Hambantota district.
3rd May	Up to 60 mm in Ampara, Monaragala, Colombo, Ratnapura, Galle and Matara districts; up to 50 mm in Gampaha, Kurunegala, Nuwara Eliya, Kegalle, Kalutara and Ratnapura districts; up to 30 mm in Kandy district; and up to 20 mm in Hambantota and Batticaloa districts.
4th May	Up to 120 mm in Anuradhapura district; up to 100 mm in Vavuniya districts; up to 70 mm in Ratnapura, Badulla and Monaragala districts; up to 60 mm in Nuwara Eliya district; up to 50 mm in Kegalle and Mannar districts; up to 30 mm in Hambantota district; and up to 20 mm in Puttalam, Kurunegala, Matale, Kandy, Colombo, Kalutara and Matara districts.
5th May	Up to 50 mm in Mannar and Anuradhapura districts; up to 30 mm in Kilinochchi, Vavuniya, Kurunegala, Gampaha, Kegalle, Ratnapura and Monaragala 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 district; up to 150-200 mm in Vavuniya and Monaragala districts; up to 100-150 mm in Kegalle, Nuwara Eliya, Ratnapura Badulla, and Ampara districts; and up to 75-100 mm in Mannar, Colombo, Galle and Hambantota districts. Above-average rainfall up to 200-300 mm is shown for in Anuradhapura district; up and to 100-200 mm in Vavuniya and Badulla districts; and up to 50-100 mm in Mannar, Kegalle, Ratnapura, Ampara, and Badulla districts. Below-average rainfall up to 10-25 mm is shown in Jaffna, Trincomalee and Batticaloa districts.

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 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 6^th - 12^th May: Total rainfall more than 135 mm in Galle and Matara districts; up to 125 mm in Ratnapura district; up to 115 mm in Monaragala district; and up to 105 mm in Gampaha, Badulla and Hambantota districts.
From 13^th - 19^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 Kurunegala, Gampaha, Colombo and Kegalle districts.

IRI Model Forecast: 
From 4^th – 9^th May: Total rainfall up to 100 mm in Badulla, Nuwara Eliya and Kandy districts; up to 75 mm in Matale, Kegalle, Ratnapura, Monaragala and Ampara districts; and up to 50 mm in Trincomalee, Batticaloa, Polonnaruwa, Hambantota, Matara, Galle, Kalutara, Colombo, Gampaha, Kurunegala and Anuradhapura districts.

MJO based OLR predictions:

For the next 15 days: 
MJO shall not have an impact on the rainfall in Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific sea state: April 20, 2020 

SSTs in the east-central Pacific were near the borderline of weak El Niño during mid-April. However, patterns in atmospheric variables were mainly neutral. Most model forecasts favor warm-neutral SST conditions during the rest of spring, cooling to average by summer. The official CPC/IRI outlook is consistent with these model forecasts, calling for a continuation of ENSO-neutral through fall.

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