Weekly Hydro-meteorological Report, 28, March 2019

Highlights:

•   The IRI weekly rainfall forecast predicts up to 25 mm of total rainfall in the central and southern parts of the island during 27 Mar – 1 Apr.
•   Between 20 – 25 Mar: up to 30 mm of rainfalls were recorded in Colombo and Ratnapura districts on the 23rd.
•  From 19 – 25 Mar: up to 18 km/h, northeasterly winds were experienced by the entire island.
•   0.5 ⁰C above average sea surface temperature was observed in the southeastern seas around Sri Lanka.

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Summary

Monitoring

Weekly Monitoring: No significant rainfalls were recorded in any part of the island on March 20th. On the 21st, Batticaloa, Badulla, Ampara, Nuwara Eliya and Ratnapura districts received up to 20 mm of rainfall; and Puttalam, Kurunegala, Kegalle, Kandy, Kalutara and Galle districts up to 10 mm. On the 22nd, Mannar and western regions of Anuradhapura district received up to 10 mm of rainfall. On the 23rd, Colombo and Ratnapura districts received up to 30 mm of rainfall; Gampaha, Kegalle, Kalutara, Galle, Nuwara Eliya, Monaragala and Hambantota districts up to 20 mm and Puttalam, Anuradhapura, Kurunegala and Matara districts up to 10 mm. No significant rainfalls were recorded in any part of the island during the period 24th and 25th.

Total Rainfall for past week :  The RFE 2.0 tool shows total up to 25-50 mm in Ratnapura district; and up to 10-25 mm in Mannar, Anuradhapura, Kurunegala, Gampaha, Colombo, Kalutara, Galle, Matara, Hambantota, Kandy, Nuwara Eliya, Badulla, Monaragala and Ampara districts. Below average rainfall up to 25-50 mm is shown for Kurunegala, Nuwara Eliya, Badulla, Monaragala and Matara districts; and up to 10-25 mm is shown for most parts of the island.

Monthly Monitoring: During February – Above average rainfall conditions up to 210 mm were experienced in Ratnapura district; up to 180 mm in Kegalle, Gampaha, Colombo, Kalutara, Galle, Matara Monaragala and Badulla districts and in Northern regions of Anuradhapura district; and up to 60 mm in most parts of the island. Below average rainfall conditions up to 90 mm were experienced by Polonnaruwa, Batticaloa, Ampara, Jaffna and Kilinochchi districts and some regions of Puttalam, Anuradhapura, Trincomalee and Monaragala, districts. The CPC Unified Precipitation Analysis tool shows up to 300 mm of total rainfall in Colombo, Ratnapura, Kalutara, Galle and Matara districts; up to 150 mm in Kegalle, Gampaha and Nuwara Eliya districts; up to 100 mm in Puttalam, Kurunegala, Anuradhapura, Vavuniya, Mullaitivu, Trincomalee, Batticaloa, Ampara, Hambantota, Matale, Kandy, Monaragala and Badulla districts; and up to 75 mm in Vavuniya and Kilinochchi districts. 

Predictions

14-day prediction:
NOAA NCEP Models:

From 26th Mar – 2nd Apr: Not Available

From 3rd – 9th Apr: Total rainfall up to 25 mm in Colombo, Ratnapura, Galle and Matara districts; up to 5-15 mm Gampaha, Kegalle, Kandy, Nuwara Eliya, Badulla, Monaragala, Hambantota and Ampara districts.

IMD WRF Model Forecast: 

29th Mar: Up to 40 mm of rainfall in Ratnapura district; and up to 10 mm in Nuwara Eliya district.

30th Mar: No Rainfall.

IRI Weekly forecast:
From 27th Mar – 1st Apr: Total rainfall up to 25 mm in Puttalam, Kurunegala, Matale, Polonnaruwa, Batticaloa, Gampaha, Kegalle, Kandy, Badulla, Ampara, Colombo, Ratnapura, Nuwara Eliya, Badulla, Monaragala, Kalutara, Galle, Matara and Hambantota districts.

Ocean State (Text Courtesy IRI)
PACIFIC SEAS STATE : March 19, 2018

SSTs in the tropical Pacific increased within the weak El Niño category during February and early March, while subsurface waters became more strongly warmer than average. Patterns in the atmosphere now clearly suggest El Niño conditions. Collective model forecasts show a continuation of at least weak El Niño-level SSTs through spring and summer, likely even lasting through 2019. The official CPC/IRI outlook, with an El Niño advisory, calls for a 80% chance of El Niño prevailing during Mar-May, decreasing to 60% for Jun-Aug.

INDIAN OCEAN STATE :   0.5 ⁰C above average sea surface temperature was observed in the southeastern seas around Sri Lanka.

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