Weekly Hydro-meteorological Report, 28, January 2016

Highlights:


Slight amounts of rainfall was observed in the country during the week 19th – 25th January. Kantale received heavy rainfall on 23rd January. Ocean around Nilaveli received rainfall on 23rd and 24th January and the rest of the country did not receive significant rainfall during this period. NOAA NCEP models predict no rainfall during next week in the entire country. MJO shall be in phase 3 therefore rainfall conditions shall slightly enhance in Sri Lanka.
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Summary

Monitoring


Weekly Monitoring:During the week 19th – 25th January, eastern and south western regions received rainfall. No significant rainfall was observed in the entire country during 19th, 20th and 21st January. Ocean around Kattankudy and Kalkudah received rainfall up to 20 mm on 22nd January. Rainfall up to 100 mm was observed around Kantale on 23rd January while northern region of Polonnaruwa received rainfall up to 80 mm and southern region of Batticaloa and ocean around Nilaveli also received rainfall up to 40 mm. On 24th January, ocean around Nilaveli received rainfall up to 60 mm while Kuruvita and southern region of Nuwara Eliya received rainfall up to 50 mm. Rainfall up to 30 mm was observed around Dehiattakandiya on 25th January.


Monthly Monitoring:In the month of December north province, northern regions of Central, Uva and Sabaragamuwa provinces, northern region of Ampara, Colombo and Polonnaruwa received above average rainfall while eastern province, south province, northern region of Mannar, north eastern region of Anuradhapura, western region of Mullaitivu and the ocean around Trincomalee to Ampara, Galle to Hambantota received below average rainfall.

Predictions

14-day prediction:NOAA NCEP models predict no rainfall in the entire country during 27th January – 2nd February. The rainfall shall be slightly increased during 3rd – 9th February where eastern region of the country shall receive rainfall up to 35 mm and northern, western and central regions shall receive rainfall up to 25 mm while southern region shall not receive any rainfall.

IMD WRF Model Forecast & IRI forecast:According to the IMD WRF model, there shall not be significant rainfall throughout the country during 29th and 30th January 2016. Galle region might receive slight rainfall on the 30th. IRI CFS models predict total precipitation up to 25 mm around eastern, central and southern regions during 27th January to 1st February 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 21, 2016 :During mid-January 2015 the tropical Pacific SST was at a strong El Niño level, having peaked in November and December. 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 January-March 2016 season in progress. The beginning of a gradual weakening of the SST anomaly is underway, with the event dissipating to neutral conditions by late spring or early summer 2016.
INDIAN OCEAN STATE : 0.5 degree Celsius above average sea surface temperature was observed around Sri Lanka.
MJO STATE :MJO shall be in phase 3 therefore shall slightly enhance rainfall in Sri Lanka.