Weekly Hydro-meteorological Report, 21, March 2019

Highlights:

•   The IRI weekly rainfall forecast predicts up to 75 mm of total rainfall in the central parts of the island during 20 – 25 Mar.
•   Between 13 – 19 Mar: up to 50 mm of rainfall was recorded in Gampaha district on the 18th.
•  From 12 – 18 Mar: up to 22 km/h, easterly winds were experienced by the entire island.
•   0.5 ⁰C above average sea surface temperature was observed in the eastern seas around Sri Lanka.

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Summary

Monitoring

Weekly Monitoring: On March 13th, coastal regions of Batticaloa district received up to 10 mm of rainfall. No significant rainfalls were recorded in any part of the island on the period 14th. On the 15th, Gampaha district received up to 5 mm of rainfall. On the 16th, Kurunegala, Nuwara Eliya, Ratnapura and Kalutara districts received up to 10 mm of rainfall; Puttalam, Gampaha, Kegalle, Colombo and Badulla districts up to 5 mm. On the 17th, Colombo, Kalutara, Ratnapura and Galle districts received up to 20 mm of rainfall; and Puttalam, Kurunegala, Gampaha, Kegalle and Nuwara Eliya districts up to 10 mm. On the 18th, Gampaha districts received up to 50 mm of rainfall; Kegalle, Colombo, Kalutara, Galle and Matara districts up to 30 mm; Puttalam, Kurunegala, Ratnapura and Hambantota districts up to 20 mm; and Kandy, Nuwara Eliya and Badulla districts up to 10 mm. No significant rainfalls were recorded in any part of the island on the period 19th.

Total Rainfall for past week :  The RFE 2.0 tool shows total up to 25-50 mm in Gampaha, Colombo, Kalutara, Galle, Kegalle and Ratnapura districts; and up to 10-25 mm in Puttalam, KurunegalaKandy, Nuwara Eliya, Matara and Hambantota districts. Below average rainfall up to 25-50 mm is shown for Kurunegala, Matale, Ratnapura, Badulla, Ampara and Monaragala 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 20th – 26th Mar: Total rainfall up to 25 mm in Ratnapura, Galle, Matara, Hambantota and Gampaha districts; and up to 5-15 mm in Kegalle, Kandy, Nuwara Eliya, Badulla, Monaragala and Ampara districts.

From 27th Mar – 2nd Apr: Total rainfall up to 35 mm in Ratnapura district; up to 15-25 mm Gampaha, Kegalle, Galle and Matara districts; and up to 5-15 mm in Puttalam, Kurunegala, Kandy, Nuwara Eliya, Badulla, Monaragala and Ampara districts.

IMD WRF Model Forecast: 

22nd Mar: Up to 160 mm of rainfall in Galle district; up to 80 mm in Ratnapura district; up to 40 mm in Ampara district; and up to 20 mm in Anuradhapura, Kurunegala and Kalutara districts.

23rd Mar: Up to 160 mm of rainfall in Kalutara, Ratnapura and Galle districts.

IRI Weekly forecast:
From 20th – 25th Mar: Total rainfall up to 75 mm in Kegalle, Ratnapura, Badulla, Kandy, Monaragala and Ratnapura districts; and up to 25 mm in most parts of the island.

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 eastern seas around Sri Lanka.

MJO STATE :  MJO shall not have an effect in the next 5 days; shall enhance in the following 5 days; and again, shall not have an effect in the next 5 days.