Weekly Hydro-meteorological Report, 31, March 2016

Highlights:


Dry weather conditions continued in the entire country during 23rd – 26th March and thereafter north east, east and central regions of the country received rainfall during 27th – 29th March. Highest rainfall of 70 mm was observed around Katugastota and central region of Monaragala while Elahara and Polonnaruwa regions received rainfall up to 60 mm on this day. NOAA NCEP model predict no rainfall in the entire country during next two weeks whereas IRI CFS models predict up to 100 mm total precipitation around Nuwara Eliya and Badulla during 30th March- 4th April. MJO is in phase 8 and shall significantly suppress rainfall in Sri Lanka.
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Summary

Monitoring


Weekly Monitoring:Rainfall received in north east, east and central regions of the country during 23rd– 29th March while dry weather conditions were observed in other regions. No rainfall was observed during 23rd – 26th in the entire country. Up to 35 mm rainfall was observed in the eastern region of Matale, near Balangoda and Hasalaka, Rakwana, Girandurukotte and near coastal region of Batticaloa on 27th March. Central region of Monaragala and Katugastota received up to 70 mm rainfall while near Elahara and Polonnaruwa regions were obtained up to 60 mm rainfall on 28th March. Polonnaruwa, Nuwara Eliya, Kandy and Matale districts received rainfall up to 40 mm on the same day. Rainfall was observed up to 20 mm in southern region of Badulla, central region of Monaragala, western region of Nuwara Eliya and Kandy on 29th March whereas up to 40 mm rainfall was received around sea near Pottuvil.


Monthly Monitoring:During February 2016 most regions of the country observed below average rainfall; and above average rainfall was observed in the northern region of Ratnapura, western region of Gampaha, Colombo, Kalutara, Galle, north region of Matara and the sea around western, south eastern and south western regions of the country.

Predictions

14-day prediction:NOAA NCEP models predict no rainfall in the entire country during 30th March - 5th April and 6th – 12th April.

IMD WRF Model Forecast & IRI forecast:IMD WRF model forecast Colombo, Gampaha, Kalutara, Galle and coastal region of western province to receive up to 60 mm rainfall on 1st April whereas slight amount of rainfall shall obtain in the rest of the country except northern region. On 2nd April, up to 60 mm rainfall is expected around Kegalle. IRI CFS models predict up to 100 mm total precipitation around Nuwara Eliya and Badulla and up to 50 mm total precipitation in Monaragala and Rathnapura during 30th March- 4th April.

Seasonal Prediction:As per IRI Multi Model Probability Forecast for April to June, the total 3 month precipitation shall be climatological. 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 March 17, 2016 :During mid-March 2016 the tropical Pacific SST was weakening, but still at a strong El Niño level. All atmospheric variables continue to support the El Niño pattern, including weakened trade winds and excess rainfall in the east-central tropical Pacific, extending eastward. Most ENSO prediction models indicate continued weakening El Niño conditions over the coming several months, returning to neutral by late spring or early summer 2016, and a chance for La Niña development by fall.
INDIAN OCEAN STATE :0.5 degree Celsius above average sea surface temperature was observed around Sri Lanka.
MJO STATE :MJO phase is in 8 and therefore shall suppress rainfall in Sri Lanka in a significant manner.