Weekly Hydro-meteorological Report, 15, June 2017

Highlights:

•   The WRF model predicts up to 36 mm of rainfall in Western coastal regions of the country on 16th of June.  
•   Between 7-13 Jun: Rainfall up to 60 mm was recorded in Jaffna district on the 7th.
•   From 4-10 Jun: minimum temperature of 15 ^OC was recorded from Nuwara Eliya district while northern and eastern coastal regions of the island recorded a maximum temperature between 30-35 ^OC.
•   From 6-12 Jun: up to 54 km/h, northwesterly winds were experienced by the whole island.
•   0.5 ^OC above average sea surface temperature was observed in the northern and northeastern seas of Sri Lanka.

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Summary

Monitoring

Weekly Monitoring: On June 7th, Jaffna district received up to 60 mm of rainfall; Kilinochchi. Mullaitivu and Vavuniya districts up to 20 mm; most northern regions of the island up to 10 mm; and adjacent northern sea up to 90 mm. On the 8th Mannar district received up to 10 mm of rainfall. Several refions of Mullaitivu and Mannar districts received up to 10 mm on the 9th. No significant rainfalls were recorded during the 10th-13th period.

Total Rainfall for past week :  The RFE 2.0 tool shows total rainfall of 10-25 mm in Jaffna, Kilinochchi, Mullaitivy and Mannar districts; up to 5-10 mm in Vavuniya and Anuradhapura districts. It shows below average rainfall up to 50 mm for Puttalam, Kurunegala, Kandy, Nuwara Eliya, Kegalla, Ratnapura, Gampaha, Colombo, Kalutara, Badulla, Monaragala and Galle districts; up to 10-25 mm in Matale, Polonnaruwa, Ampara, Hambantota and Matara districts.

Monthly Monitoring: During May - above average rainfall conditions were experienced in the entire island except for Batticaloa, Ampara and Jaffna districts. Ratnapura district received up to 450 mm above average rainfall; and Kegalla, Kalutara, Matara and Galle districts received up to 360 mm; Nuwara Eliya district up to 240 mm and many parts of the island up to 120 mm. Monthly total rainfall for Ratnapura, Kalutara and Galle districts amounted to 540 mm; up to 420 mm for Kegalla district; and 360 mm for Nuwara Eliya, Colombo and Gampaha districts. The CPC Unified Precipitation Analysis tool shows ~1000 mm of total rainfall in Ratnapura district; up to ~750 mm in Kegalla, Colombo, Kalutara and Galle districts; and up to ~500 mm Kurunegala, Gampaha, Nuwara Eliya and Matara districts; up to 300 mm in Puttalam, Kandy, Badulla, Monaragala and Hambantota districts; and up to 200 mm in Anuradhapura, Polonnaruwa and Matale districts.

Predictions

14-day prediction:
NOAA NCEP Models:
From 14th-20th Jun: Total rainfall between 125-135 mm Ratnapura district; up to 95-105 mm in Colombo, Kegalla, Kandy, Nuwara Eliya and Galle districts; up to 45-55 mm in Gampaha, Matale, Badulla and Monargala districts; up to 35-45 mm in Puttalam, Kurunegala and Ampara districts.
From 21st-27th June: Total rainfall between 95-105 mm in Kegalla, Colombo and Ratnapura districts; up to 45-55 mm in Gampaha, Kurunegala, Kandy, Nuwara Eliya and Galle districts; up to 25-35 mm in Kurunegala and Puttalam districts.

IMD WRF Model Forecast & IRI forecast:
16th Jun: Up to 8 mm of rainfall in Puttalam, Gampaha, Colombo, Kalutara, Galle, Matara, Badulla, Batticaloa, Ampara and Ratnapura districts.
17th Jun: Up to 36 mm of rainfall in Puttalam, Gampaha and Kalutara districts; up to 8 mm of rainfall in Kurunegala, Kegalla, Ratnapura, Galle and Matara districts.

Seasonal Prediction:  Apr to Jun: the total 3-month precipitation shall be climatological for the whole country. The 3-month temperature has more than 70-80% likelihood in the whole of the island of being in the above-normal tercile.

Ocean State (Text Courtesy IRI)
PACIFIC SEAS STATE : June 8, 2017
In early June 2017, the tropical Pacific remained in an ENSO-neutral state, with SSTs near the El Niño threshold in the east-central tropical Pacific but the atmosphere maintaining ENSO-neutral patterns. The collection of latest ENSO prediction models indicates approximately even chances for SSTs at warm-neutral versus weak El Niño levels in early summer, but slightly greater chances for ENSO-neutral than weak El Niño from late summer onward into the rest of 2017.

INDIAN OCEAN STATE : 0.5 0C above average sea surface temperature was observed in the northern and northeastern seas of Sri Lanka.

MJO STATE :  MJO shall enhance the rainfall in Sri Lanka.