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Thursday, July 20, 2017

Weekly Hydro-meteorological Report, 20, July 2017


  •   The WRF model predicts up to 36 mm of rainfall in Western regions of the country on 22nd of July. 
  •   Between 12- 18 Jul: Rainfall up to 30 mm was recorded in Batticaloa and Ampara districts on the 12th.
  •   From 9-15 Jul:  minimum temperature of 20  OC was recorded from Nuwara Eliya district while Northern and Eastern regions of the island recorded a maximum temperature between 30-35 OC.
  •   From 11-17 Jul: up to 54 km/h, northwesterly winds were experienced by the entire island.
  •   0.5 OC above average sea surface temperature was observed in the northern and southern seas around Sri Lanka.

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Weekly Monitoring: On July 12th, Batticaloa and Ampara districts received up to 30 mm of rainfall; and northern regions of Badulla and Monaragala districts up to 20 mm. No significant rainfalls were recorded in any part of the island during the period 13th – 17th. On the 18th Kurunegala and Gampaha districts received up to 20 mm of rainfall; and Puttalam, Colombo, Kalutara, Ratnapura, Kegalla, Kandy and Matale districts up to 10 mm.

Total Rainfall for past week :  The RFE 2.0 tool shows total rainfall of 10-25 mm in Batticaloa, Ampara, Badulla, Monaragala, Kurunegala, Gampaha, Matale and Kandy districts; and up to 5-10 mm in many parts of the central and southern islands. It shows below average rainfall up to 100 mm in Ratnapura district; up to 25-50 mm in Kandy, Kegalla, Colombo, Kalutara and Galle districts; and up to and 10-25 mm in Gampaha, Matale, Kandy, Badulla, Monaragala, Matara and Hambantota districts.

Monthly Monitoring: During June - below average rainfall conditions were experienced in the entire island except for northern regions of Monaragala and adjacent regions of Ampara district. Ratnapura, Kalutara and Galle districts received up to 240 mm below average rainfall; and Colombo and Nuwara Eliya districts received up to 150 mm; and most parts of the island up to 120 mm. The CPC Unified Precipitation Analysis tool shows ~200 mm of total rainfall in Monaragala and Ampara districts; up to ~150 mm Badulla district; and up to ~100 mm Kurunegala, Gampaha, Colombo, Kalutara, Nuwara Eliya, Kandy, Kegalla, Ratnapura and Galle districts; up to 75 mm in Puttalam, Matale and Matara districts.


14-day prediction:
From 19th – 25th Jul: Total rainfall between 25-35 mm in Puttalam, Kurunegala, Gampaha, Kegalla, Kandy, Ratnapura, Batticaloa, Polonnaruwa, Ampara and Galle districts; and between 15-25 mm in most parts of the island.
From 26th Jul - 1st  Aug: Total rainfall between 25-35 mm in Colombo, Ratnapura and Galle districts; and 15-25 mm in Gampaha, Puttalam, Kurunegala, Kandy, Nuwara Eliya, Ampara, Polonnaruwa and Matara districts.

IMD WRF Model Forecast & IRI forecast:
  21st Jul: Up to 36 mm of rainfall in Puttalam, Kalutara, Ratnapura and Galle districts; and up to 8 mm of rainfall in Mannar, Kurunegala, Gampaha, Colombo, Matara, Hambantota and Kegalla districts.
  22nd Jul: Up to 36 mm of rainfall in Puttalam, Kurunegala, Gampaha, Colombo, Kalutara, Galle, Matara, Ampara and Ratnapura districts; and up to 8 mm of rainfall in Mannar, Matale , Batticaloa, Badulla, Monaragala and Kegalla 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 : July 19, 2017
In mid-July 2017, the tropical Pacific remained in an ENSO-neutral state, with SSTs near the El Niño threshold in the east-central tropical Pacific but the atmosphere maintaining ENSO-neutral patterns. The collection of latest ENSO prediction models indicates ENSO-neutral as the most likely condition during summer through fall and into winter with chances for El Niño development at about 35-40%.

INDIAN OCEAN STATE :  0.5 OC above average sea surface temperature was observed in the northern and eastern seas around Sri Lanka.

MJO STATE :  MJO shall not have a significant impact on the rainfall in Sri Lanka in the next 10 days and shall suppress the rainfall in the following 5 days.

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