Weekly Hydro-meteorological Report, 14, June 2018

Highlights:

•   The NCEP weekly rainfall forecast predicts total rainfall between 95-105 mm in Kegalle, Ratnapura and Kalutara districts during 13th – 19th June.
•   Between 6-12 Jun: up to 50 mm of rainfall was recorded in Ratnapura, Kalutara, Matara and Galle districts on the 6th.
•   From 3-9 Jun: minimum temperature of 20 ^OC was recorded from Nuwara Eliya  and Badulla districts while eastern coastal areas of the island recorded a maximum temperature between 30-35 ^OC.
•  From 5-11 Jun: up to 36 km/h, westerly winds were experienced by the entire island.
•   Average sea surface temperature was observed in the seas around Sri Lanka.

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Summary

Monitoring

Weekly Monitoring: On June 6th, Ratnapura, Kalutara, Matara and Galle districts received up to 50 mm of rainfall; Jaffna, Kegalla, Nuwara Eliya and Gampaha districts up to 30 mm; and Kilinochchi, Mullaitivu, Kurunegala, Kandy, Colombo, Hambantota, Badulla and Monaragala districts up to 20 mm. On the 7th, Kurunegala, Matale, Kandy, Badulla, Kegalla, Nuwara Eliya and Ratnapura received up to 30 mm of rainfall; and Puttalam, Gampaha, Colombo, Kalutara, Galle, Matara, Polonnaruwa Hambantota and Ampara up to 20 mm. On the 8th, several regions of Kegalla, Kalutara and Ratnapura districts received up to 20 mm of rainfall. On the 9th, Kurunegala, Puttalam, Nuwar Eliya and Ratnapura districts received up to 20 mm. On the 10th, several regions of Anuradhapura and Puttalam districts received up to 15 mm of rainfall. No significant rainfalls were recorded in any part of the island during 11th and 12th.

Total Rainfall for past week :  The RFE 2.0 tool shows total rainfall 75-100 mm of total rainfall in Ratnapura district; up to 50-75 mm in Kurunegala, Kegalla, Kalutara, Galle, Nuwara Eliya and Kandy districts; and 25-50 mm in Puttalam, Anuradhapura, Matale, Polonnaruwa, Ampara, Monaragala, Badulla, Hambantota and Matara districts. Above average rainfall up to 50-100 mm is shown for Ratnapura district and below average rainfall up to 25-50 mm is shown for Badulla and Monaragala districts. 

Monthly Monitoring: During May - above average rainfall conditions were experienced by the entire island. Puttalam, Kurunegala, Anuradhapura, Matale and Polonnaruwa districts received up to 360 mm above average rainfall; Vavuniya, Trincomalee, Gampaha, Colombo, Kegalla, Ratnapura, Galle, Matara, Kandy, Badulla and Ampara districts up to 300 mm; and rest of the country up to 120 mm. The CPC Unified Precipitation Analysis tool shows ~750 mm of total rainfall in Kurunegala, Kegalla, Colombo, Kalutara and Ratnapura districts; up to 500 mm PuttalamGampaha, Galle, Matara, Hambantota, Nuwara Eliya, Kandy, Matale, Anuradhapura, Polonnaruwa, Ampara, Badulla and Monaragala districts; up to ~300 mm Mullaitivu and Trincomalee districts; and up to 200 mm in rest of the country. 

Predictions

14-day prediction:
NOAA NCEP Models:

From 13th -19th Jun: Total rainfall between 95-105 mm in Kegalle, Ratnapura and Kalutara districts; between 75-85 mm in Colombo, Gampaha and Galle districts; between 65-75 mm in Kurunegala, Kandy and Nuwara Eliya districts; between 55-65 mm in Puttalam and Matara districts; between 35-45 mm in Matale, Badulla and Hambantota districts; between 15-25 mm in Anuradhapura, Polonnaruwa, Monaragala and Hambantota districts.

From 20th - 26th Jun: Total rainfall between 115-125 mm in Ratnapura and Kegalle districts; between 105-115 mm in Colombo and Kalutara districts; between 95-105 mm in Gampaha and Galle districts; between 85-95 mm in Kurunegala, Kandy, Nuwara Eliya, Ratnapura and Matara districts; between 65-75 mm in Puttalam, Matale, Badulla and Hambantota districts; between 45-55 mm in Anuradhapura, Polonnaruwa and Monaragala districts.

IMD WRF Model Forecast: 

15th Jun: Up to 40 mm of rainfall expected in Gampaha, Colombo, Kegalle, Kandy, Matale, Nuwara Eliya, Ampara, Monaragala, Ratnapura, Hambantota and Matara districts; Up to 20 mm in Mannar, Vavuniya, Anuradhapura, Trincomalee, Puttalam, Polonnaruwa, Batticaloa, Kurunegala, Badulla and Galle districts.

16th Jun: Up to 40 mm of rainfall expected in Kurunegala, Kalutara, Galle, Matara, Hambantota and Monaragala districts; Up to 20 mm in Mannar, Anuradhapura, Polonnaruwa, Puttalam, Matale, Nuwara Eliya, Badulla and Ratnapura districts.

IRI Weekly forecast:
From 13th -18th Jun: Total rainfall between 25-50 mm in Gampaha, Colombo, Kalutara, Galle, Ratnapura and Kegalle districts; Up to 25 mm total rainfall rest of the island.

Ocean State (Text Courtesy IRI)
PACIFIC SEAS STATE : May 18, 2018

In mid-May 2018, the east-central tropical Pacific waters reflected ENSO-neutral conditions. Most key atmospheric variables also indicated neutral conditions, although the upper level wind anomalies show remnants of La Niña. The subsurface water temperature continued to be above-average. The official CPC/IRI outlook calls for neutral conditions through the September-Novemeber season, with a nearly 50% chance of El Niño development by year’s end. The latest forecasts of statistical and dynamical models collectively favor weak El Niño development by year’s end, but forecasters hedge on this due to low confidence at this time of year.

INDIAN OCEAN STATE :   Average sea surface temperature was observed in the seas around Sri Lanka.

MJO STATE :  MJO shall not have an impact on the rainfall in Sri Lanka in the next 10 days and shall suppress in the following 5 days.