Weekly Hydro-meteorological Report, 9 October, 2014

Highlights

Monitoring and Prediction

Slightly heavy rainfall was observed throughout the coastal areas of the country and mostly around the south-west region during the previous week and despite the tropical cyclone Hudhud only mild rainfall is expected in the entire country during next week except in south- western regions where up to 150- 200 mm rainfall is expected in coming six days. The north-western sea of Sri Lanka shows an above average sea surface temperature.
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Summary

Monitoring


Weekly Monitoring::On 1st and 2nd of October high rainfall was observed throughout the country averaging around 15 mm and from 3rd to 6th an average of 10 mm- 15 mm rainfall was observed around the coastal areas in general. On 7th October a very heavy rainfall around 50 mm was observed around the south-west region. Rainfall up to 100 mm was observed in Ratnapura and Kalmunai areas on the same day.


Monthly Monitoring:An average rainfall of 6 mm-10 mm was observed throughout the country with higher precipitation observed in the south-western regions of Sri Lanka during September. Highest rainfall during this month was observed in Ratnapura district. Also the decadal rainfall average was increased from 4 mm to 18 mm within a week.

Predictions

14-day prediction:The entire country shall receive total rainfall up to 65 mm during 8th of October to 14th October. Rainfall is expected to increase in the next week (15th- 21s ) resulting in heavier rainfall in south- western regions of Sri Lanka.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model the entire country shall receive high rainfall on the 10th of October. By 11th of October the south-west region shall receive average rainfall around 7.6 mm- 35.6 mm whereas the rest of the country shall not receive significant rainfall. Heavy rainfall continues in the Bay of Bengal due to the tropical cyclone Hudhud.

Seasonal Prediction:As per IRI Multi Model Probability Forecast issued in September for the season October to December 2014, Rainfall shall remain climatological while the temperature shall be above normal with a high probability.

PACIFIC SEAS STATE September 18, 2014 :During August through early September the observed ENSO conditions moved to those of a borderline El Niño. Most of the ENSO prediction models indicate weak El Niño conditions during the September-November season in progress, strengthening slightly and peaking at weak strength during winter 2014-15 and lasting into the first few months of 2015.
INDIAN OCEAN STATE :Around 0.50C above average sea surface temperature in northern sea was observed.
MJO STATE :MJO is weak and therefore shall not influence the rainfall in Sri Lanka.