Weekly Hydro-meteorological Report, 7, January 2016

Highlights:


During the week 26th December – 1st January, highest rainfall was observed in western region of Kilinochchi and the ocean near Delft Island on 27th December. Relatively high rainfall was observed in several regions in Matale, Moneragala and Badulla. NOAA NCEP models predict increase of rainfall during next week in south eastern region. MJO phase is in 7 and shall suppress rainfall of the country significantly. A continuation of strong El Niño conditions is predicted by the IRI and therefore in January the rainfall shall be low.
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Summary

Monitoring


Weekly Monitoring:Slight amounts of rainfall was observed in the country during 26th December – 1st January. Gal-oya national park received rainfall up to 50 mm on 26th December while Avissawella, north eastern region of Kandy and Horowpotana received rainfall up to 30 mm. On 27th December heavy rainfall was observed up to 170 mm in western region of Kilinochchi and ocean near Delft island received rainfall up to 160 mm while ocean near Jaffna received rainfall up to 100 mm and Laggala, Hettipola, Thanamalvila and Badulla received rainfall up to 90 mm. Rainfall up to 90 mm was observed around somawathie chaithya sanctuary on 28th December. Rainfall up to 60 mm was observed in eastern region of Kandy on 29th December while Kuliyapitiya received rainfall up to 50 mm. No rainfall was observed on 30th December and on 31st December north eastern region of Moneragala received rainfall up to 80 mm. From 1st January onward, the daily prediction is not available.


Monthly Monitoring::North province, northern regions of Central, Uva and Sabaragamuwa provinces, northern region of Ampara, Colombo and Polonnaruwa received above average rainfall while eastern province, south province, northern region of Mannar, north eastern region of Anuradhapura, western region of Mullaitivu and the ocean around Trincomalee to Ampara, Galle to Hambantota received below average rainfall.

Predictions

14-day prediction: NOAA NCEP models predict relatively high rainfall in south eastern of the country compared to the rest of country during 6th – 12th January. Total rainfall up to 85 mm is expected in south eastern region and the rest of the country is expected to receive rainfall up to 45 mm. During 13th – 19th January, the rainfall is expected to decrease and total rainfall up to 35 mm is expected to receive around south western region and the rest of the country is expected to receive rainfall up to 25 mm.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model, northern region of Badulla and ocean around Kirinda shall receive rainfall up to 65 mm on 8th January while central to eastern regions of the country shall receive up to 35 mm. Northern region of Ampara and Badulla, Galle, Kalutara and Kuruwita is expected to receive rainfall up to 35 mm on 9th January while the eastern and western regions of the country shall receive slight amounts of rain. IRI CFS models predict total rainfall up to 50 mm in south western, southern, central and south eastern regions of the country

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

PACIFIC SEAS STATE December 17, 2015 :During mid-December 2015 the tropical Pacific SST was at a strong El Niño level. All atmospheric variables strongly support the El Niño pattern, including weakened trade winds and excess rainfall in the east-central tropical Pacific. The consensus of ENSO prediction models indicate continuation of strong El Niño conditions during the December-February 2015-16 season in progress. Further strengthening is possible, but unlikely, into mid-winter 2015-16, with the event slowly weakening during spring 2016.
INDIAN OCEAN STATE : 1 degree Celsius above average sea surface temperature was observed around Sri Lanka.
MJO STATE :MJO is in Phase 7 and therefore shall suppress rainfall in Sri Lanka in a significant manner.