Weekly Hydro-meteorological Report, 26 November, 2015

Highlights:


Up to 40 mm rainfall was observed in northern and eastern regions of the country during 17th-23rd November. Heavy rainfall up to 130 mm was observed in ocean near Mannar on 23rd November and up to 110 mm in ocean near Mullaitivu on 18th November. Rainfall up to 80 mm was observed around northern region of Moneragala and Welioya on 20th November. High rainfall shall continue in northern and north-eastern regions of the country in the next two weeks.
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Summary

Monitoring


Weekly Monitoring:On 17th November, rainfall up to 40 mm was observed around Pulmoddai while ocean near Ampara received rainfall up to 50 mm. On 18th November, ocean near Mullaitivu received rainfall up to 110 mm while Moneragala received rainfall up to 50 mm. On 19th November, rainfall up to 60 mm was observed around Haputale, Hasalaka and Kurunegala. Rainfall up to 80 mm was observed around northern region of Moneragala and Welioya on 20th November. Rainfall up to 30 mm was observed in eastern region of Galle and northern region of Mannar on 21st November while ocean near eastern province also received rainfall up to 30 mm. On 22nd November, ocean near Puttalam received rainfall up to 70 mm while Bingiriya and Polonnaruwa received rainfall up to 50 mm. On 23rd November, ocean near Mannar received rainfall up to 130 mm while Wattala and Colombo 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 northern and eastern regions of the country compared to the rest of the country during 25th November – 1st December. Total rainfall above 135 mm is expected during the week in these regions and total rainfall up to 95 mm is expected in the north western region. Rest of the country is expected to receive rainfall up to 45 mm. These models predict the rainfall to increase during 2nd – 8th December and total rainfall above 135 mm is expected in eastern region, total rainfall up to 115 mm is expected in northern region and rest of the country 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 in ocean near Mullaitivu on 27th November while Nuwara Eliya to Badulla region shall receive rainfall up to 65 mm and rest of the country shall receive slight amounts of rainfall. On 28th November Mannar, Kattankudy and Yala shall receive rainfall up to 65 mm and the rest of the country shall receive slight amounts of rainfall. IRI CFS models predict total rainfall up to 75 mm in north eastern and Badulla regions of the country during 25th – 30th 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 Celsius above average temperature was observed around Sri Lanka.
MJO STATE :MJO is neutral and therefore shall not affect the rainfall in Sri Lanka.