Weekly Hydro-meteorological Report, 23 July, 2015

Highlights:


Southern region and the ocean near southern province mostly received rainfall up to 10-50 mm during 14th July – 20th July 2015. Rainfall up to 20-30 mm observed in the ocean near Southern and south western regions on 15th, 16th, 17 and 18th July. Rainfall up to 30 mm observed in Kegalle and Nuwara-Eliya on 19th July and on 20th July and rainfall up to 30 mm observed in southern province and in the ocean near southern province. NOAA models predict high rainfall in south western region of the country in the next fortnight.
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Summary

Monitoring


Weekly Monitoring:During the time period 14th July – 20th July 2015, southern province mostly received rainfall up to 10 mm/day. On 14th July, southern province, Colombo, Kalutara, Ratnapura and Moneragala received rainfall up to 10 mm. On 15th July, ocean near Galle and Matara received rainfall up to 20 mm and on 16th July Ocean near western and southern provinces received rainfall up to 30 mm while Galle, Matara and Ratnapura received rainfall up to 10 mm. Rainfall up to 20 mm was observed in the ocean near Galle on 17th and 18th July and on 19th July, up to 30 mm rainfall was observed in southern region of Kegalle, western region of Nuwara-Eliya district and in the ocean near northern province. On 20th July rainfall up to 30 mm was observed in the ocean near southern province while Galle district observed rainfall up to 50 mm and Matara, Hambantota, southern region of Ratnapura and southern region of Moneragala also received rainfall up to 30 mm.


Monthly Monitoring:: In the month June 2015, western, Sabaragamuwa and south eastern regions of the country received above average rainfall of upto 8 mm/day. The rest of the country received below average rainfall during this month.

Predictions

14-day prediction: NOAA NCEP models predict low rainfall in south western region of the country during 22nd July – 04th August. Up to 45 mm total rainfall is expected during these two weeks while the rest of the country shall not receive significant amount of rainfall.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model Western region of the country shall receive rainfall up to 35 mm/day on 24th July. The rest of the country shall receive slight amounts of rainfall. The rainfall shall be reduced on 25th July and western and south eastern region of the country shall receive rainfall up to 8 mm and the rest of the country shall not receive significant rainfall. IRI CFS model also predicts high rainfall in South western and eastern provinces on 22nd – 27th July.

Seasonal Prediction:As per IRI Multi Model Probability Forecast for July to September, the total 3 month precipitation has a 40% chance 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 July 16, 2015 :During late June through mid-July 2015 the SST was at a moderate El Niño level. All atmospheric variables 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 moderate, and likely becoming strong, El Niño conditions during the July-September 2015 season in progress. Further strengthening between summer and fall is likely, with the event lasting into early 2016.
INDIAN OCEAN STATE : 1 0C above average temperature was observed around Sri Lanka.
MJO STATE :MJO is weak and therefore shall not have a significant impact on the rainfall in Sri Lanka.