Weekly Hydro-meteorological Report, 03, March 2016

Highlights:


Dry weather conditions prevailed in most parts of the country between 24th February and 1st March where western, southern and south western regions received rainfall. On 24th February highest rainfall of 90mm was observed around the northern region of Ratnapura and western region of Ampara received rainfall up to 60 mm. Hikkaduwa received rainfall up to 70 mm on 27th February. For the next week, NOAA NCEP model predicts rainfall in western and south western regions and dry weather conditions for the rest of the country. MJO is in phase 7 shall suppress rainfall in Sri Lanka in a significant manner.
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Summary

Monitoring


Weekly Monitoring:During the period 24th February – 1st March, western, southern and south western regions of the country received rainfall. 90 mm of rainfall was observed around northern region of Ratnapura on 24th February while western region of Ampara received rainfall up to 60 mm. On 25th of February, the sea near Colombo received rainfall up to 50 mm, while rainfall up to 30 mm was observed in northern region of Colombo, Hambantota and the sea around Hambantota. The sea around Nilaveli received rainfall up to 20 mm on 26th February. Hikkaduwa received rainfall up to 70 mm on 27th February and no significant rainfall was observed in the entire country at the end of the week.


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, Matara and the sea around western, south eastern and south western regions of the country.

Predictions

14-day prediction:NOAA NCEP models predict rainfall in western and south western regions of the country where rainfall up to 55 mm is expected in south western region and up to 45 mm rainfall in western region during 2nd – 8th March. Rest of the country is not expected to receive rainfall. These models predict that there shall be no rainfall in entire country during 9th – 15th March.

IMD WRF Model Forecast & IRI forecast:According to the IMD WRF model, the sea around Ampara and Hambantota is expected to receive rainfall up to 35 mm on 4th March while Ampara, Galle and central regions of the country shall receive slight amounts of rainfall. Rest of the country is not expected to receive rainfall. On 5th February, rainfall up to 125 mm is expected to receive in Galle where coastal region of Ampara shall receive rainfall up to 35 mm. Eastern, central, western and southern regions shall receive slight amounts of rainfall. IRI CFS models predict up to 50 mm total precipitation in western sea, Colombo, Kalutara, Kegalle, Nuwara Eliya and Badulla during 2nd – 7th March.

Seasonal Prediction:As per IRI Multi Model Probability Forecast for March to May, the total 3 month precipitation has 40% 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 February 18, 2016 :During mid-February 2016 the tropical Pacific SST was still at a very strong El Niño level, having peaked in November and December. All atmospheric variables continue to support the El Niño pattern, including weakened trade winds and excess rainfall in the east-central tropical Pacific. Most ENSO prediction models indicate slowly weakening El Niño conditions over the coming several months, returning to neutral by late spring or early summer 2016, with a chance for La Niña development during fall.
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.