Weekly Hydro-meteorological Report, 21, January 2016

Highlights:


Apart from the ocean around the eastern province receiving slight amounts of rainfall on 13th and 14th of January, no significant rainfall was observed during 13th – 19th January in the entire country. NOAA NCEP models predict slight increase of rainfall during next week in northern and central regions of the country. MJO shall be in phase 3 and rainfall conditions shall be enhanced slightly in Sri Lanka.
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Summary

Monitoring


Weekly Monitoring:Mild showers up to 10 mm was observed around the eastern ocean near Kalkudah on 13th and 14th January. No significant rainfall was observed anywhere in the country during 13th – 19th January.


Monthly Monitoring:In December, Northern Province, northern regions of Central, Uva and Sabaragamuwa provinces, northern part of Ampara, Colombo and Polonnaruwa received above average rainfall. Below average rainfall was experienced in the eastern province, southern province, northern region of Mannar, north eastern region of Anuradhapura, western region of Mullaitivu and the ocean around Trincomalee to Ampara, Galle to Hambantota.

Predictions

14-day prediction: NOAA NCEP models predict rainfall up to 45 mm in northern, north western, north eastern and central regions of the country; and up to 25mm in Southern region during 20th – 26th January. The rainfall shall decrease gradually and the entire country shall experience dry weather conditions from 27th January – 2nd February.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model, eastern coastal region around Batticaloa, Mullaitivu and the northern region of Badulla are expected to receive slight amounts of rainfall on 22nd January, rest of the country shall experience dry weather conditions. On 23rd January, rainfall is expected to increase and coastal region around Batticaloa and Ampara shall receive rainfall up to 35 mm while northern region of Matale, Kurunegala and southern region of Puttalam are also expected to receive slight amounts of rainfall. IRI CFS models predict total rainfall up to 75 mm around the ocean near Kalkudah during 20th to 25th January 2016.

Seasonal Prediction:As per IRI Multi Model Probability Forecast for February to April, the total 3 month precipitation has 40% likelihood in north eastern areas and 50% likelihood in the rest of the country of being below average. 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 January 14, 2016 :During mid-December 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 December-February 2015-16 season in progress. Further strengthening is possible, but unlikely, into mid-winter 2015-16, with the event slowly weakening during spring 2016.
INDIAN OCEAN STATE : Neutral Sea Surface temperature was observed around Sri Lanka.
MJO STATE :MJO shall be in phase 3 in the next few days therefore shall slightly enhance rainfall in Sri Lanka.