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Friday, December 23, 2016

Weekly Hydro-meteorological Report, 22, December 2016


  •  The IMD WRF model predicts rainfall up to 35 mm on 23rd December in Galle, Matara and Balangoda regions.  
  •  Between Dec 13–19: highest rainfall of 100 mm was recorded on the 19th in the surrounding regions of Illavankulam in Puttalam district.
  •  From Dec 11–17: minimum temperature of 15 OC was recorded from Nuwara Eliya district while many parts of the island recorded a maximum temperature between 30-35 OC.
  •  From Dec 13–19: up to 10 km/h north easterly winds were experienced in the northern and southern regions of the island.

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Weekly Monitoring: On December 13th Galle and Matara districts received up to 20 mm of rainfall. On 14th no significant rainfalls were recorded in any part of the island. On 15th Telulla and Galge in Monaragala district received up to 30 mm of rainfall; and Koslanda in Badulla district received up to 20 mm. On 16th Hasalaka received up to 30 mm of rainfall; and Hettipola up to 20 mm. On the 17th Kalutara, Galle, Ratnapura, Badulla, Monaragala, Kandy and Matale districts received up to 20 mm of rainfall. No significant rainfalls were recorded in any part of the island on the 18th. On 19th northern coastal regions of Puttalam districts received up to 100 mm of rainfall; Anuradhapura district received up to 50 mm; Trincomalee, Matale and Polonnaruwa districts up to 30 mm; Jaffna, Kilinochchi, Mullaitivu, Mannar, Batticaloa, Ampara, Vavuniya and several regions of Monaragala districts up to 20 mm of rainfall; and adjacent eastern sea regions received up to 80 mm of rainfall.

Total Rainfall for past week : The RFE 2.0 tool shows total rainfall up to 75 mm in the northern regions of Puttalam district; up to 50 mm for Anuradhapura, Trincomalee, Kandy and Badulla districts; and up to 25 mm for many parts of the island. It shows above average rainfall of 25-50 mm for the northern regions of Puttalam district; below average rainfall of 100-200 mm for the coastal regions of the Ampara district; 50-100 mm below average rainfall for rest of the eastern coastal belt; and 25-50 mm below average rainfall for many parts of the island..

Monthly Monitoring:During November - above average rainfall conditions were experienced in Jaffna, Kilinochchi, Kegalla, Gampaha, Colombo, Galle, Matara and several regions of Kurunegala and Puttalam districts. Monthly average rainfall for these regions amounted to 360 mm/month; rest of the island experienced below average rainfall conditions with a monthly average not exceeding 180 mm/month. The CPC Unified Precipitation Analysis tool shows ~300 mm of total rainfall in Kilinochchi, Mullaitivu, Gampaha, Colombo, Ratnapura, Batticaloa, Kalutara, Hambantota, Galle and Matara districts; ~200 mm in Vavuniya, Mannar, Anuradhapura, Polonnaruwa, Puttalam, Kurunegala, Kegalla and Monaragala districts; and 150 mm in rest of the island.


14-day prediction:
NOAA NCEP Models: From 21st – 27th December: Total rainfall up to 45 mm for the coastal regions of Jaffna; 25-35 mm for Kilinochchi district; and 15-25 mm in western coastal regions and Vavuniya district.
From 28th Dec- 03rd Jan: Total rainfall between 65-75 mm is expected in the south eastern coastal regions; 45-55 mm in Ampara, Monaragala, Hambantota and Matara districts; and 25-35 mm in Badulla and Ratnapura districts.

IMD WRF Model Forecast & IRI forecast: Up to 35 mm of rainfall is expected on the 23rd in Galle, Matara and Balangoda; and up to 7 mm of rainfall in rest of the south western parts of the island. On the 24th, coastal regions of Trincomalee district will receive up to 7 mm of rainfall.

Seasonal Prediction: As per IRI Multi Model Probability Forecast for January to March 2017, the total 3-month precipitation has 40-50% likelihood of being in the above-normal tercile for the whole island. The 3-month temperature has more than 70-80% likelihood in the entire country of being in the above-normal tercile during this period.

Ocean State (Text Courtesy IRI)
PACIFIC SEAS STATE : December 15, 2016
During mid-December 2016 the tropical Pacific SST anomaly was near -0.5C, the threshold for weak La Niña. Also, most of the atmospheric variables across the tropical Pacific have been consistent with weak La Niña conditions, although subseasonal atmospheric variability weakened some of them in late November. The upper and lower atmospheric winds have been suggestive of a strengthened Walker circulation, and the cloudiness and rainfall have also been consistent with weak La Niña conditions. The collection of ENSO prediction models indicates SSTs near the threshold of La Niña persisting through mid-winter, then weakening to cool-neutral by later winter.

INDIAN OCEAN STATE : Sea surface temperature was climatological in the seas around Sri Lanka.

MJO STATE : For the next 15 days: MJO shall suppress the rainfall for the next 10 days and shall not have a significant impact on rainfall for the following 5 days.

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