Weekly Hydro-meteorological Report, 12 November, 2015

Highlights:


Up to 40 mm rainfall was observed in northern, north eastern, north central and southern regions of the country during the time period 4th-10th November. Heavy rainfall up to 120 mm was observed in ocean near Ampara on 9th November and ocean near Jaffna on 8th November. Rainfall up to 80 mm was observed in ocean near Jaffna on 7th November. IRI and IMD models predict a decrease in rainfall in next two weeks but still high rainfall is expected during this period.
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Summary

Monitoring


Weekly Monitoring:During 4th– 10th November northern, north eastern, north central and southern regions mostly received rainfall. On 4th November only light rainfall was observed on land and the ocean near Ampara received rainfall up to 50 mm. On 5th November rainfall up to 70 mm was observed in Kuruwita while Central, Uva, Sabaragamuwa and Western provinces received rainfall up to 50 mm. Horowupotana, Trincomalee and Mannar areas received up to 50 mm rainfall on 6th November. Rainfall up to 80 mm was observed in the ocean near Jaffna on 7th November while Vavuniya, Kilinochchi, Periyamadu, Lunugala and ocean near Vavuniya received rainfall up to 50 mm. On 8th November, ocean north of Jaffna Peninsula received rainfall up to 100 mm while Lunugala, ocean near Ampara and Galle received rainfall up to 70 mm. On 9th November, ocean near Ampara received rainfall up to 120 mm and Jaffna received rainfall up to 50 mm. On 10th November only the ocean near Ampara and Jaffna received rainfall up to 50 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 11th November – 17th 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 18th- 24th November 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 65 mm is expected around Girandurukotte on 13th November while Yala and northern region of Central province shall receive rainfall up to 35 mm and rest of the country also shall receive slight amounts of rainfall. On 14th November, northern, southern, eastern and central regions shall receive rainfall up to 35 mm. IRI CFS models predict total rainfall up to 100 mm in north western region of the country during 11th – 16th 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 October 15, 2015 :During late September through mid-October 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 October-December 2015 season in progress. Some slightly further strengthening is possible into later fall, with the event slowly weakening during spring 2016.
INDIAN OCEAN STATE : 1.5 degrees Celcius above average temperature was observed around Sri Lanka.
MJO STATE :MJO is in phase 4 therefore shall slightly enhance rainfall in Sri Lanka.