Weekly Hydro-meteorological Report, 19 November, 2015

Highlights:


Up to 40 mm rainfall was observed in northern, north eastern and north western regions of the country during the time period 10th-16th November. Heavy rainfall up to 180 mm was observed in ocean near Kilinochchi on 13th November and up to 160 mm in Jaffna, Kilinochchi and Mannar island on 15th November. Rainfall up to 100 mm was observed in Giriulla on 12th November. Every prediction model predict increase of rainfall during the next week. Below average sea surface temperature was observed around Sri Lanka
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Summary

Monitoring


Weekly Monitoring:During 10th– 16th November northern, north eastern and north western regions mostly received rainfall. On 10th November Jaffna and Ampara received rainfall up to 40 mm. On 11th November rainfall up to 60 mm was observed around Yala and Kumana. Rainfall up to 100 mm was observed around Giriulla and eastern region of Batticaloa on 12th November while Western, Central and Sabaragamuwa provinces also received rainfall up to 60 mm. On 13th November, ocean near Kilinochchi received rainfall up to 180 mm while Kilinochchi, Vavuniya, Trincomalee and Mannar received rainfall up to 140 mm. On 14th November, ocean near Batticaloa received rainfall up to 100 mm and entire country received rainfall up to 70 mm. On 15th November Jaffna, Kilinochchi and Mannar Island received rainfall up to 160 mm while north eastern region of the country received rainfall up to 70 mm. On 16th November only Negombo, ocean near Gampaha and Ampara received rainfall up to 30 mm.


Monthly Monitoring::In October 2015, almost entire country received above average rainfall while the ocean near northern and western provinces, southern region of Puttalam and eastern region of Matara received below average rainfall.

Predictions

14-day prediction: NOAA NCEP models predict relatively high rainfall in eastern region of the country compared to the rest of the country during 18th November – 24th November. Total rainfall above 135 mm is expected during the week in eastern region and total rainfall up to 115 mm is expected in northern and north central regions. Rest of the country is expected to receive rainfall up to 95 mm. These models predict the rainfall to increase during 25th November – 1st December and total rainfall above 135 mm is expected in eastern region, total rainfall up to 115 mm is expected in rest the country while southern and western regions shall receive total rainfall up to 95 mm.

IMD WRF Model Forecast & IRI forecast:According to the IMD WRF model rainfall up to 125 mm is expected around Bogawantalawa on 20th November while Giriulla and Rambukkana shall receive rainfall up to 65 mm and rest of the country also shall receive slight amounts of rainfall. On 14th November, ocean near eastern region of the country shall receive rainfall up to 125 mm while Colombo and Chilaw shall receive rainfall up to 65 mm and the rest of the country also shall receive slight amounts of rainfall. IRI CFS models predict total rainfall up to 100 mm in northern and central regions of the country during 18th – 23rd November.

Seasonal Prediction:As per IRI Multi Model Probability Forecast for November to January, 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 November 19, 2015 :During late October through early November 2015 the tropical Pacific SST was at a strong El Niño level. All atmospheric variables strongly support the El Niño pattern, including weakened trade winds and excess rainfall in the east-central tropical Pacific. The consensus of ENSO prediction models indicate continuation of strong El Niño conditions during the November-January 2015-16 season in progress. Some slightly further strengthening is possible into early winter 2015-16, with the event slowly weakening during spring 2016.
INDIAN OCEAN STATE : 0.5 degrees Celcius below average temperature was observed around Sri Lanka.
MJO STATE :MJO phase is in 3 therefore shall slightly enhance rainfall in Sri Lanka.