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Thursday, April 27, 2017

Weekly Hydro-meteorological Report, 27, April 2017


  •   The WRF model predicts up to 36 mm of rainfall in Western region of country on 27th of April 
  •   Between 19-25 Apr: highest rainfalls of 20 mm were recorded on the 24th in Kegalla, Ratnapura, Kalutara, Galle and Matara districts.
  •   From 16-22 Apr: 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 18-24 Apr: up to 18 km/h, northwesterly winds were experienced by the southern regions; and speeds less than 14 km/h in the northern regions of the island.
  •   Average sea surface temperature was observed in the seas around Sri Lanka.

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Weekly Monitoring: No significant rainfalls were recorded in any part of the island during the period of 19th-23rd April. On the 24th Kegalla, Ratnapura, Kalutara, Galle and Matara districts received up to 20 mm of rainfall. On the 25th several regions of Nuwara Eliya district received up to 10 mm of rainfall.

Total Rainfall for past week :  The RFE 2.0 tool shows total rainfall up to 25 mm Kegalla, Ratnapura, Colombo, Kalutara and Galle districts. It shows below average rainfall of 50-100 mm for Kurunegala, Puttalam, Anuradhapura, Kegalla, Gampaha, Colombo, Kalutara and Ratnapura districts; and 25-50 mm for most parts of the island.

Monthly Monitoring: During March - above average rainfall conditions were experienced in the entire island except for Hambantota district, which received up to 90 mm of below average rainfall. Anuradhapura, Kurunegala and Kandy received up to 150 mm above average rainfall; and many parts of the island received up to 120 mm. Monthly average rainfall for Anuradhapura, Matale, Polonnaruwa, Kurunegala, Gampaha, Colombo, Ratnapura, Kegalla, Nuwara Eliya Kandy and Badulla districts amounted to 270 mm/month; and 180 mm/month for many parts of the island. The CPC Unified Precipitation Analysis tool shows ~500 mm of total rainfall in Kurunegala, Gampaha, Colombo, Kegalla, Kandy and Ratnapura districts; up to ~300 mm in Kandy, Anuradhapura, Polonnaruwa, Puttalam, Kalutara, Galle, Badulla, Monaragala, Nuwara Eliya and Matale districts; up to ~200 mm Vavuniya, Mannar, and Matara districts; and up to 150 mm for the rest of the island.


14-day prediction:
From 26th Apr – 02nd May: Total rainfall between 25-35 mm in Gampaha, Kurunegala, Kegalla, Ratnapura and Matara districts; up to 15-25 mm in Puttalam, Anuradhapura, Matale, Kandy, Nuwara Eliya, Hambantota, Colombo, Kalutara and Galle districts; up to 5-15 mm in Mannar, Mullaitivu, Vavuniya, Trincomalee, Polonnaruwa, Ampara and Monaragala districts.
From 03rd – 09th May: Total rainfall between 25-35 mm in Kalutara and Galle districts; up to 15-25 mm in Kurunegala, Matale, Gampaha, Kegalle, Kandy, Ratnapura and Matara districts; up to 5-15 mm in Puttalam, Anuradhapura, Polonnaruwa, Ampara, Badulla, Nuwara Eliya, Monaragala, Hambantota and Colombo districts.

IMD WRF Model Forecast & IRI forecast:
  27th Apr: Up to 36 mm rainfall in Colombo district; and up to 8 mm rainfall in Gampaha, Kalutara and Kegalla districts.
  28th Apr: Up to 3 mm rainfall in Gampaha and Puttalam 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 : April 20, 2017
By mid-April 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. Across the western and central Pacific, the pattern of cloudiness, rainfall, and winds remains suggestive of La Nina conditions. The collection of ENSO prediction models indicates increasing chances of El Nino into the summer and fall of 2017.

INDIAN OCEAN STATE :  Average sea surface temperature was observed in the seas around Sri Lanka.

MJO STATE :  MJO shall suppress the rainfall in Sri Lanka

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