Weekly Hydro-meteorological Report, 28 Aug, 2014

Highlights

Monitoring and Prediction

Rainfall was observed during the previous week, mostly in the south-western region of the country. Highest rainfall was observed in the Kaluthara district. The sea to the west of Sri Lanka also received high rainfall.
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Summary

Monitoring


Weekly Monitoring:: The entire country received rainfall during 19th- 22nd August. During this period heavy rainfall was observed in the western, north-western and south-western regions of the country. Up to 100 mm rainfall was observed on the 21st and 22nd in Kaluthara. Rainfall completely stopped in most of the regions in Sri Lanka on the 23rd with rainfall only observed in Colombo and Gampaha districts. On the 24th and 25th up to 50 mm rainfall was observed in the borders of Monaragala and Ampara districts. During 11th – 20th August rainfall in Sri Lanka was mostly concentrated in south-western, north-central regions and also in the region between the central mountain and the eastern coast.


Monthly Monitoring:A less than average rainfall was observed throughout the country during July.

Predictions

14-day prediction:Up to 75 mm rainfall is expected in South-Western Sri Lanka during 27th August- 2nd September. During the week 3rd- 9th September, rainfall shall spread to north-western and north-central regions with south-western region expected to receive up to 75 mm rainfall.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model the western half of the country shall receive up to 35 mm rainfall during 29th and 30th of August. IRI models predict upto 50 mm rainfall in south-western coastal region and adjacent sea during 26th- 31st August. Heavy rainfall events are not expected during this period.

Seasonal Prediction:As per IRI Multi Model Probability Forecast issued in August for the season September to November 2014, Rainfall shall remain climatological while the temperature shall be above normal with 60- 70% probability.

PACIFIC SEAS STATE August 21, 2014 :During July through early-August the observed ENSO conditions were neutral. Most of the ENSO prediction models indicate warming to El Niño levels coming around early northern fall, peaking at weak strength during winter 2014-15 and lasting into the first few months of 2015.
INDIAN OCEAN STATE :More than 0.50 C above average sea surface temperature was observed around Sri Lanka.
MJO STATE :MJO is at phase 2 and shall enhance rainfall conditions in Sri Lanka