- The WRF model predicts up to 125 mm of rainfall in Colombo and Ratnapura districts on 26th May.
- Between 15-23 May: highest rainfall of 90 mm was recorded on the 18th in Colombo district.
- From 14-20 May: minimum temperature of 15 OC was recorded from Nuwara Eliya district while northern and northeastern regions of the island recorded a maximum temperature between 30-35 OC.
- From 16-22 May: up to 36 km/h, westerly winds were experienced by the southern regions; and up to 28 km/h northwesterly in the northern regions of the island.
- 0.5 OC above average sea surface temperature was observed in the seas around Sri Lanka.
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Weekly Monitoring: On May 15th, Kegalla and Ratnapura districts received up to 30 mm of rainfall; Galle and Matara districts up to 20 mm; and most of the southwestern parts of the island up to 10 mm. No significant rainfalls were recorded on the 16th and 17th. On the 18th Colombo district received up to 90 mm of rainfall; Gampaha district up to 70 mm; Kalutara and Ratnapura districts up to 50 mm; Puttalam, Kurunegala, Kegalla, Kandy, Nuwara Eliya and Galle districts up to 30 mm; and Matale and Matara districts up to 20 mm. On the 19th Gampaha district received up to 50 mm of rainfall; Puttalam and Kurunegala districts up to 30 mm; and Kegalla, Batticaloa and Ampara districts up to 20 mm. Up to 10 mm of rainfall was recorded in several parts of the island on the 20th and 21st. On the 22nd Ratnapura and Badulla districts received up to 30 mm of rainfall; Gampaha, Colombo, Kegalla, Kandy, Monaragala and Ampara districts up to 20 mm; and most of the southern of the parts of the island up to 10 mm. On the 23rd Ratnapura district received up to 30 mm of rainfall; Kegalla, Kandy, Galle, Matara, Badulla, Batticaloa and Monaragala districts up to 20 mm; and several regions of the southern parts of the island up to 10 mm.
Total Rainfall for past week : The RFE 2.0 tool shows total rainfall up to 100 mm in Colombo district; up to 75 mm in Puttalam, Kurunegala, Gampaha and Kalutara districts; and up to 50 mm Kegalla, Kandy, Nuwara Eliya, Badulla, Monaragala, Ampara, Matara and Galle districts. It shows above average rainfall of 10-25 mm for Puttalam, Kurunegala, Colombo and Gampaha districts. Below average rainfall of 25-50 mm is shown for Kalutara, district; and up to 25-50 mm for Galle, Ratnapura, Nuwara Eliya and Badulla districts.
Monthly Monitoring: During April - below average rainfall conditions were experienced in the entire island. Matale, Gampaha, Colombo, Ratnapura and Kandy districts received up to 210 mm below average rainfall; and many parts of the island received up to 150 mm. Monthly average rainfall for Anuradhapura, Kurunegala, Gampaha, Colombo, Ratnapura, Kegalla, Galle and Matara districts amounted to 210 mm/month; and 150 mm/month for Puttalam, Kandy, Matale, Badulla, Hambantota and Monaragala districts. The CPC Unified Precipitation Analysis tool shows ~200 mm of total rainfall in Anuradhapura, Gampaha, Colombo, Kalutara, Galle and Ratnapura districts; up to ~100 mm in Matale, Kandy, Nuwara Eliya, Badulla, Monaragala, Kurunegala and Hambantota districts; and up to ~75 mm Ampara, Puttalam and Mannar districts;
NOAA NCEP Models:
From 24th – 30th May: Total rainfall between 75-85 mm in Mullaitivu district; between 65-75 mm in Jaffna, Kilinochchi, Vavuniya, Anuradhapura, Trincomalee, Kalutara and Galle district; 55-65 mm in Mannar, Colombo, Ratnapura and Matara districts; 45-55 mm in Polonnaruwa, Gampaha and Kegalle districts;35-45 mm in Puttalam, Kurunegala, Matale, Nuwara Eliya and Hambantota districts; 25-35 mm in Batticaloa, Kandy, Badulla and Monaragala districts; 15-25 mm in Ampara district.
From 31st May – 6th Jun: Total rainfall between 35-45 mm in Colombo and Ratnapura districts; 25-35 mm in Jaffna, Kilinochchi, Mullaitivu, Mannar, Vavuniya, Anuradhapura, Trincomalee, Kegalle and Gampaha districts; 15-25 mm in Puttalam, Kurunegala, Nuwara Eliya and Matara districts; 5-15mm in Polonnaruwa, Matale, Kandy, Badulla, Monaragala and Hambantota districts.
IMD WRF Model Forecast & IRI forecast:
25th May: Up to 125 mm rainfall in Galle district; up to 65 mm of rainfall in Kegalle, Ratnapura, Kalutara and Matara districts; up to 35 mm in Puttalam, Kurunegala, Gampaha, Colombo, Nuwara Eliya and Hambantota districts; up to 8 mm of rainfall in Batticaloa, Kandy, Ampara, Badulla and Monaragala districts.
26th May: up to 125 mm of rainfall in Colombo and Ratnapura districts; up to 65 mm in Gampaha, Kegalla and Kalutara districts; up to 36 mm in Puttalam, Kurunegala, Nuwara Eliya, Galle and Matara districts; up to 8 mm Anuradhapura, Matale, Kandy, Nuwara Eliya, Hambantota, Badulla, Monaragala and Ampara districts.
Seasonal Prediction: Apr to Jun: the total 3-month precipitation shall be climatological for the whole country. The 3-month temperature has more than 70-80% likelihood in the whole of the island of being in the above-normal tercile.
Ocean State (Text Courtesy IRI)
PACIFIC SEAS STATE : May 18, 2017
By mid-May 2017, the tropical Pacific remained in an ENSO-neutral state, with above-average SSTs present in the eastern Pacific Ocean, and near-average SSTs across the central and east-central part of the basin. The collection of ENSO prediction models indicates increasing chances of El Niño into the summer and fall of 2017.
INDIAN OCEAN STATE : 0.5 OC above average sea surface temperature was observed in the seas around Sri Lanka.
MJO STATE : MJO shall enhance the rainfall in Sri Lanka in the next 5 days and shall not have a significant impact on the following 5 days. MJO shall suppress the rainfall for the next 5 days.