Weekly Hydro-meteorological Report, 11 June, 2015

Highlights:


During 2nd – 8th June 2015, high rainfall was received throughout the week in Eastern, Western, Central and North Central provinces up to 20-40 mm. In 3rd, 5th, and 7th June, heavy rainfall up to 85 mm was observed in Polonnaruwa, Moneragala and Ampara districts. In 6th June, heavy rainfall of 120 mm was observed in the ocean near Trincomalee district. NOAA models predict high rainfall in Western and Eastern provinces in the next fortnight.
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Summary

Monitoring


Weekly Monitoring::During the time period 2nd June – 8th June 2015, Eastern, Western, Central and North Central regions of the country received rainfall. On 2nd and 3rd June, rainfall up to 30-40 mm was observed in Uva province and Polonnaruwa district and the highest rainfall of 40 mm was observed in Moneragala and Coastal area of Kilinochchi district. On 4th June, rainfall was observed in North Central and Central provinces up to 30 mm and on 5th June, up to 30 mm rainfall was observed in Western, Central and Eastern regions of the country and the highest rainfall of 85 mm was observed in Polonnaruwa. Heavy rainfall of 120 mm was observed in the ocean near Trincomalee on 6th June and high rainfall was observed in Uva province on 7th June and the highest rainfall of 85 mm was observed in Moneragala. Only Uva province showed rainfall up to 20 mm on 8th June.


Monthly Monitoring:In May 2015 Most of the country received above average rainfall. Gampaha, Colombo, Kaluthara and Galle districts as well as western regions of Kegalle and Ratnapura districts received below average rainfall. Highest monthly average rainfall in this month was observed in Anuradhapura and Vavunia districts and northern regions of Badulla and Ampara districts.

Predictions

14-day prediction: NOAA NCEP models predict high rainfall in northern region of the country during 10th – 23rd June. Up to 85 mm total rainfall is expected during the first week. The rainfall shall decrease up to 35 mm in the following week.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model Puttalam and Kegalle districts shall receive rainfall up to 125 mm/day while the western region of the country shall receive rainfall up to 65 mm on 12th June. The rest of the country shall receive light rainfall on this day. The rainfall shall decrease and western and eastern regions shall receive rainfall up to 35 mm and the rest of the country shall receive light rainfall on the 13th. IRI CFS model also predicts light rainfall in Central, Uva, Western and Northern provinces in 10th – 15th June.

Seasonal Prediction:As per IRI Multi Model Probability Forecast for June to August, 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 May 21, 2014 :During late April through mid-May 2015 the SST was at a weak to moderate Niño level. The atmospheric variables also indicate an El Niño pattern, including weakened trade winds, low Southern Oscillation Index and excess rainfall in the central tropical Pacific. The consensus of ENSO prediction models indicate weak to moderate El Niño conditions during the May-July 2015 season in progress, likely strengthening during summer and lasting through 2015.
INDIAN OCEAN STATE :0.5 degrees C above average temperature was observed around Sri Lanka. The anomaly goes further up towards southern region.
MJO STATE :MJO phase is in 2 therefore shall enhance rainfall in Sri Lanka.