Weekly Hydro-meteorological Report, 20 November, 2014

Highlights

Monitoring and Prediction

High rainfall was observed throughout the country in the previous week with dry conditions in one or two days arising in between. Rainfall shall continue to increase during next week but not in a significant level. The entire sea region of Sri Lanka shows a neutral sea surface temperature.
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Summary

Monitoring


Weekly Monitoring::Slight rainfall was observed in the north-central region on 10th of November. From 11th to 14th of November rainfall was increased in the entire country averaging upto 20 mm with highest rainfall observed in northern, western and south-east regions. On 16th of November no significant rainfall was observed throughout the country while on 16th, average rainfall of around 30 mm was observed with above 60mm in the south-east coastal region.


Monthly Monitoring:An average rainfall of 14 mm-16 mm was observed throughout the country with higher precipitation observed in the south-western regions of Sri Lanka during October. Highest rainfall during this month was observed in Uva, Sabaragamuwa and Central provinces. Also the decadal rainfall average was around 14 mm-18 mm.

Predictions

14-day prediction:The entire country shall receive rainfall above 125 mm during 19th to 25th of November. Rainfall shall decrease throughout the country averaging around 65 mm during the week of 26th November to 02nd December.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model the entire country shall receive average rainfall around 64.5 mm on 21st of November with above 124.5 mm in the entire eastern coast. Rainfall is expected to decrease in the entire country on 22nd of November with around 2.5 mm-7.6 mm in the coastal regions only.

Seasonal Prediction:As per IRI Multi Model Probability Forecast issued in October for the season November 2014 to January 2015, Rainfall shall remain climatological while the temperature shall be above normal with a high probability.

PACIFIC SEAS STATE November 6, 2014 :During September through October the observed ENSO conditions retreated from those of a borderline El Niño to a warmish ENSO-neutral state. However, most of the ENSO prediction models continue to indicate development of weak El Niño conditions during the October-December season in progress, peaking at weak strength during winter 2014-15 and lasting through most of northern spring 2015.
INDIAN OCEAN STATE :Sea surface temperature was neutral in the entire region around Sri Lanka.
MJO STATE :MJO is weak and in Phase 2 in Indian Ocean and therefore shall not influence rainfall in Sri Lanka.