Highlights: Dry conditions were mostly seen throughout the county in the previous week. The only recorded rainfall in the week was on the 29th June which was less than 10 mm in south-western and central regions of the country. In June 2016 the entire country received less than average rainfall with the south-western region of the country receiving 20- 50% below normal and the rest of the country receiving more than 75% below normal rainfall. Due to this, the average rainfall deficit in the entire country has increase up to 30 mm by the 5th July. Rainfall is only expected in the south western region of the country during the next week and extreme rainfall events are not expected. Strong wind is expected in the southern half of the country and the highest temperature is expected in the eastern and north-eastern regions of the country. MJO is weak.
Weekly Monitoring:Less than 10 mm rainfall received by south-western and central regions of the country on the 29th June. No rainfall reported in any region of the country during 30th June- 5th July 2016. Both CPC unified Precipitation analysis and RFE2 models report less than 10 mm rain in south-western and central regions during this period as well. Therefore, the rainfall received in the week (29th June- 5th July) is up to 25 mm below average in these regions.
Monthly Monitoring: ELess rainfall was seen during June 2016 compared to very heavy rains in the previous month. Rainfall was mostly in the south western region of the country which totaled up to 150- 200 mm in the entire month. This received precipitation amount is about 20- 50% less than what is usual in June in south western, western and central regions of the country. The rest of the country received more than 75% less than average rainfall in June 2016. Rainfall of only 7 days in the past 30 days was above normal. Due to prevailing dry conditions in the country the rainfall deficit in the entire country has increased to about 30 mm by 5th July.
During the week from 26th June to 2nd July, the highest temperature of 35- 40 0C is recorded in the eastern and south eastern regions of the country. The lowest temperature was around Nuwara Eliya which was 15- 20 0C. The south western region of the country was relatively cooler than the rest of the country in the night.
TReduced wind speeds were seen across the country in the previous week (28th June- 4th July). 10- 15 m/s north westerly wind was seen throughout the country at both 850 mb and 700 mb levels.
Pacific seas state: May 19, 2016
During mid-June 2016 the tropical Pacific SST anomaly was near zero, indicating ENSO-neutral conditions. The key atmospheric variables also indicate neutral ENSO condition. This includes near-average upper and lower level tropical Pacific winds, as well as near-normal cloudiness and rainfall patterns in the central and eastern equatorial Pacific. Most ENSO prediction models indicate neutral ENSO conditions during June, with likely development of La Niña (of unknown strength, but likely weak) by late July or August, lasting through fall and into winter. (Text Courtesy IRI)
Indian Ocean State
Neutral sea surface temperature anomaly was observed around Sri Lanka.
14-day prediction: NOAA NCEP models predict up to 15 mm total rainfall during 6th- 12th July 2016 in the south-western region of the country. The rest of the country shall not receive rainfall during this period. In the following week (13- 19th July) up to 25 mm rainfall is expected in the south western region while the rest of the country shall remain dry.
Weekly prediction: IMD GFS model predicts no rainfall in the entire country on the 7th July. Up to 10 mm rain is expected in the south western region on the 8th. Then on the 9th Colombo and Kalutara regions may receive up to 40 mm rainfall while the surrounding regions may receive up to 20 mm rainfall. The rest of the south western and western regions shall receive less than 10 mm rainfall. Less than 10 mm rain is expected in the western region of the country on 10th and 11th. The entire country shall not receive rainfall on 12th and 13th.
IMD WRF Model Forecast & IRI forecast:According to the IMD WRF model, less than 35 mm rain is expected on the 8th July in the western region of the country. Same rainfall condition is expected on the 9th as well. In addition, up to 7.5 mm rainfall is expected in Ampara/ Kalmunai regions on the 9th. No extreme rainfall events expected during 6th- 11th June.
Seasonal Prediction:As per IRI Multi Model Probability Forecast for July to September, 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.
NOAA CPC GFS model predicts 35- 40 0C maximum temperature along the coastal belt in the Eastern side of the country. Maximum temperature in the hill country and the Western province shall be between 25- 30 0C. During the same week, minimum temperature is expected around Nuwara Eliya and Badulla to be 15- 20 0C while in the northern region and Hambantota it shall be 25-30 0C. The minimum temperature in the rest of the country shall be 20-25 0C.
At the 850 mb level 15- 20 m/s strong wind is expected in the southern half of the country while the northern half shall have 10- 15 m/s wind. The direction of the wind shall be generally north-westerly. At the 700 mb level 10- 15 m/s westerly wind is expected throughout the country.
MJO based OLR predictions
MJO shall not have a significant impact on the rainfall in Sri Lanka.