Climate Bulletin for Sri Lanka (30 April 2020)

                                                      Highlights                             

•          The NOAA weekly rainfall forecast predicts up to 100 mm of total rainfall in Badulla district during 29 Apr - 4 May.

•          Between 22 - 27 Apr: up to 120 mm of rainfalls were recorded in Anuradhapura and Kegalle districts on the 22^nd and 26^th respectively.

•          From 21 - 27 Apr: up to 10 km/h, northeasterly winds were experienced by the entire island.

•          0.5 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
22nd April	Up to 120 mm in Anuradhapura district; up to 100 mm in Colombo and Gampaha districts; up to 70 mm in Puttalam, Kalutara, Ratnapura and Kegalle districts; up to 60 mm in Mannar and Kurunegala districts; up to 50 mm in Vavuniya, Kandy, Nuwara Eliya and Badulla districts; up to 30 mm in Matale, Ampara, Monaragala, Batticaloa,  Hambantota, Galle and Matara districts; and up to 20 mm in Kilinochchi and Polonnaruwa districts.
23rd   April	Up to 20 mm in Puttalam, Matale, Kandy, Kurunegala, Gampaha, Colombo, Kalutara, Galle, Matara, Kegalle, Ratnapura, Nuwara Eliya, Badulla, Monaragala and Hambantota districts; and up to 10 mm in most parts of the island.
24th April	Up to 20 mm in Gampaha district; and up to 10 mm in most parts of the island.
25th April	Up to 70 mm in Anuradhapura and Matale districts; up to 50 mm in Ratnapura, Badulla and Monaragala districts; up to 30 mm in Mullaitivu, Polonnaruwa and Nuwara Eliya districts; and up to 20 mm in Mannar, Gampaha, Colombo, Kalutara, Galle, Matara, Kegalle and Kandy districts.
26th April	Up to 120 mm in Kegalle district; up to 70 mm in Gampaha and Kandy districts; up to 50 mm in Kurunegala, Nuwara Eliya and Ratnapura districts; up to 30 mm in Colombo, Badulla and Monaragala districts; and up to 20 mm in Anuradhapura and Kalutara districts.
27th April	Up to 60 mm in Vavuniya, Anuradhapura Badulla and Monaragala districts; up to 50 mm in Kegalle and Ratnapura districts; up to 30 mm in Nuwara Eliya, Kalutara, Hambantota, Mannar and Gampaha districts; and up to 20 mm in Gampaha, Colombo and Matara districts.

Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 150-200 mm in Kegalle district; up to 100-150 mm in Gampaha, Colombo, and Ratnapura districts; up to 75-100 mm in Mannar, Anuradhapura, Kurunegala, Kandy, Nuwara Eliya, Badulla, Monaragala and Kalutara districts; and up to 50-75 mm in Vavuniya, Puttalam, Galle, Matara, Hambantota, Matale, and Polonnaruwa districts. Above average rainfall up to 50-100 mm is shown for in Kegalle, Gampaha, Colombo, Ratnapura and western regions of Anuradhapura district; up and to 25-50 mm in Matale, Mannar, Kurunegala, Badulla, Monaragala, Galle, and Matara districts. Below average rainfall up to 25-50 mm is shown for in Mullaitivu, Trincomalee, Polonnaruwa and northern and eastern regions of Anuradhapura district; and up to 25-50 mm in Jaffna, Kilinochchi, Batticaloa, Ampara, and Kandy districts.

Monthly Monitoring: During March – Below average rainfall conditions up to 240 mm were experienced by Anuradhapura, Kurunegala, Matale, Polonnaruwa, Ampara, Badulla, Monaragala, Kandy, Nuwara Eliya, Kegalle, Ratnapura, Colombo, Kalutara, Galle, Matara and Hambantota districts; and up to 150 mm in rest of the island. The CPC Unified Precipitation Analysis tool shows up to 100 mm of total rainfall in Kurunegala, Kegalle, Ratnapura, Nuwara Eliya, Kalutara, Galle and Matara districts; and up to 75 mm in Puttalam, Gampaha, Colombo, Badulla and Kandy districts.

 Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

IMD NCMWRF Forecast:
From 29^th Apr - 5^th May: Total rainfall up to 45 mm in Puttalam, Kurunegala, Kegalle, Gampaha, Ratnapura, Galle and Matara districts; up to 35 mm in Colombo and Hambantota districts; and up to 25 mm in Matale, Kandy, Nuwara Eliya and Ampara districts.

From 6^th - 12^th May: Total rainfall up to 95 mm in Galle and Matara districts; up to 85 mm in Ratnapura district; up to 75 mm in Kegalle and Hambantota districts; and up to 55 mm in Puttalam, Kurunegala, Matale, Kandy, Badulla, Monaragala and Ampara districts.

IRI Model Forecast: 
From 29^th Apr – 4^th May: Total rainfall up to 100 mm in Badulla district; up to 75 mm in Kandy, Nuwara Eliya and Monaragala districts; and up to 50 mm in Polonnaruwa, Matale, Kurunegala, Kegalle, Ratnapura, Hambantota, Ampara and Batticaloa 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: 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

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