Weekly Hydro-meteorological Report, 7 May, 2015

Highlights:


Around 15- 20 mm rainfall was observed throughout the country during 29th April to 5th May 2015. A random increase and decrease in rainfall was observed during this period. Above average rainfall was observed throughout the country during April except in north eastern regions of the country. NOAA predicts a continuation of high rainfall in Sri Lanka in the next two weeks.
Download Full Report




Summary

Monitoring


Weekly Monitoring:: Up to 30 mm/day rainfall was observed during 29th April- 5th May 2015. This is reduction in rainfall compared to the previous week. High rainfall was observed on the 29th of April where southern and south western regions as well as the northern region received up to 20 mm rainfall while the rest of the country received up to 10 mm rainfall. Thereafter during the next 3 days (1st- 3rd May) rainfall was only observed in the south western region of the country. Once again the entire country received rainfall on the 3rd of May. South eastern and Kalutara regions received up to 30 mm rainfall on this day. Highest rainfall of the week with a magnitude of 60 mm was observed on the 5th of May in Badulla and Matale districts.


Monthly Monitoring: In April 2015 the entire country received above average rainfall except in Trincomalee, Batticaloa, Jaffna and Polonnaruwa districts and the northern regions of Ampara district.

Predictions

14-day prediction: NOAA NCEP models predict high rainfall in the entire the country during the next fortnight.

IMD WRF Model Forecast & IRI forecast: According to the IMD WRF model, the western and south western regions of the country shall receive up to 35 mm rainfall on 8th and 9th of May 2015. The rest of the country shall receive light rainfall during these two days.

Seasonal Prediction:As per IRI Multi Model Probability Forecast for April to June, the total 3 month precipitation shall be climatological. The 3 month average temperature has more than 60- 70% likelihood of being in the above-normal tercile during this period.

PACIFIC SEAS STATE April 16, 2014 :During March through early April 2015 the SST met the threshold for weak Niño conditions. Most of the atmospheric variables now indicate an El Niño pattern, including weakened trade winds, low Southern Oscillation Index and excess rainfall in the vicinity of the dateline. The consensus of ENSO prediction models indicate weak El Niño conditions during the AprilJune 2015 season in progress, likely strengthening during summer and lasting through 2015
INDIAN OCEAN STATE :0.5 degrees C above average temperature was observed around Sri Lanka
MJO STATE :MJO continues to be weak and therefore shall not have a significant impact on the rainfall in Sri Lanka