Weekly Hydro-meteorological Report, 16 May, 2014

Highlights

Monitoring and Prediction
Existing rainfall condition shall remain constant (8-10 mm/day) till the end of prediction period (15th-21st May) and No significant rainfall events are expected. However, few models predict dryer condition (less than 25 mm/6 days) than previous months for entire country during 15th-20th May 2014.

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Summary

Monitoring


Weekly Monitoring:During 6th-12th May 2014, Sri Lanka received rainfall ranged 5-70 mm. During 6th-10th May, northern 2/3rd of the island received more rainfall compared to the rest of the island.


Monthly Monitoring:The border regions of Kurunegala and Anuradhapura and, Vavuniya and Mannar districts received above normal rainfall during April 2014 and rest of the districts received below normal rainfall during April 2014.

Predictions

14-day prediction:During 15th-28th May 2014, western districts of Sri Lanka shall receive 65-55 mm of rainfall and shall spread throughout the country in a reducing manner.

IMD WRF Model Forecast & IRI forecast:For 17th of May, IMD WRF model predicts less than 8 mm/day of rainfall for Gampaha-Galle districts, Kegalle and Ratnapura districts and, is likely to spread in reducing manner towards nearby regions. For 18th of May, the model predicts less than 3 mm of rainfall for the boarders of Trincomalee, Batticaloa, Monaragala, Badulla, Nuwara-Eliya and Ratnapura districts and for the same day rest of the island is likely to be dry. IRI model predicts dry condition (less than 25 mm/6 days) for entire country during 15th-20th May 2014.

1 Month Prediction:Overall-Existing rainfall condition shall remain constant (8-10 mm/day) till the end of prediction period (15th-21st May). Western Slopes- Existing rainfall condition shall decrease till 19th May and thereafter it shall increase slightly till 23rd. No significant rainfall events are expected. Western Coast- The rainfall pattern persisting in the western slopes shall observe in this region. Eastern Slope- The rainfall shall decrese gradually till 18th and increase gradually during the prediction period. Eastern Coast- The rainfall pattern persisting in the western slopes shall observe in this region with low rates of the rainfall trend. Northern- The rainfall condition shall remain constant (6-8 mm/day) during the prediction preiod. Southern Region- The rainfall pattern persisting in the entire country shall observe in this region (constant rainfall of 3-7 mm/day).

Seasonal Prediction:As per IRI Multi Model Probability Forecast issued on May 2014; for June 2014 to August 2014, there is a more than 70% probability for temperature to be above normal for Hambantota district and 60-70% probability for temperature to be above normal for rest of the regions in Sri Lanka in the country while the rainfall is to be climatological.

PACIFIC SEAS STATE May 15, 2014 :During April through mid-May the observed ENSO conditions moved from warm-neutral to the borderline of a weak El Niño condition. Most of the ENSO prediction models indicate a continued warming trend, with a transition to sustained El Niño conditions by the early northern summer.
INDIAN OCEAN STATE :Eastern and Southeastern seas of Sri Lanka showed +0.50C anomaly during 4th-10th May 2014.
MJO STATE :MJO is at phase 2 and is likely to impact on Sri Lanka rainfall condition.