Weekly Hydro-meteorological Report, 16, May 2019

Highlights:

•   The IRI weekly rainfall forecast predicts up to 75 mm of total rainfall in Badulla and Nuwara Eliya districts during 15 – 20 May.
•   Between 7 - 13 May: up to 90 mm of rainfall was recorded in Trincomalee district on the 12th.
•  From 7 - 13 May: up to 36 km/h, westerly winds were experienced by the central and southern regions of the island.
•   Average sea surface temperature was observed in the seas around Sri Lanka.

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Summary

Monitoring

Weekly Monitoring: No significant rainfalls were recorded in any part of the island on May 7th and 8th. On the 9th, Mullaitivu district received up to 10 mm of rainfall. On the 10th, Mullaitivu and Vavuniya districts received up to 20 mm of rainfall; Mannar and Kilinochchi districts up to 10 mm; and Anuradhapura district up to 5 mm. On the 11th, Batticaloa, Ampara and Monaragala districts received up to 10 mm of rainfall. On the 12th, Trincomalee districts received up to 90 mm of rainfall; Mullaitivu, Anuradhapura, Polonnaruwa and Batticaloa districts up to 20 mm; and Vavuniya and Badulla districts up to 10 mm. On the 13th, Badulla, Monaragala, Ratnapura and Kalutara districts received up to 5 mm of rainfall.

Total Rainfall for past week :  The RFE 2.0 tool shows total up to 50-75 mm in Trincomalee district; up to 25-50 mm in Batticaloa district; and 25-50 mm in Vavuniya, Mullaitivu, Anuradhapura and Polonnaruwa districts. Above average rainfall up to 50-100 mm is shown for Trincomalee district; and up to 25-50 mm in Batticaloa district. Below average rainfall up to 25-50 mm is shown for Puttalam, Gampaha, Colombo, Kalutara, Galle, Kegalle, Ratnapura, Nuwara Eliya and Matara districts; and up to 10-25 mm in Kurunegala, Anuradhapura, Matale, Kandy, Badulla, Monaragala, Hambantota and Ampara districts.

Monthly Monitoring: During April – Above average rainfall conditions up to 60 mm were experienced in western regions of Kurunegala district and central regions of Anuradhapura district. Below average rainfall conditions up to 240 mm were experienced by Matale, Kandy, Nuwara Eliya, Kegalle, Colombo, Kalutara, Galle, Matara, Ratnapura, Hambantota, Badulla and Monaragala districts; and up to 180 mm in rest of the island. The CPC Unified Precipitation Analysis tool shows up to 500 mm of total rainfall in Gampaha district; up to 300 mm in Puttalam, Kurunegala, Anuradhapura, Kegalle, Ratnapura, Colombo, Kalutara and Galle districts; up to 200 mm in Matale, Kandy, Nuwara Eliya and Matara districts; and up to 100 mm in Mannar, Vavuniya, Polonnaruwa, Badulla, Monaragala, Batticaloa, Ampara and Hambantota districts.

Predictions

14-day prediction:
NOAA NCEP Models:

From 15th – 21st May: Total rainfall up to 45 mm Ratnapura and Galle districts; up to 25-35 mm in Gampaha, Colombo and Matara districts; and up to 15-25 mm in Kurunegala, Kegalle, Nuwara Eliya and Hambantota districts.

From 22nd – 29th May: Total rainfall up to 55 mm in Galle and Ratnapura districts; up to 35-45 mm in Gampaha, Colombo, Kegalle and Matara districts; up to 25-35 mm in Puttalam and Kurunegala districts; up to 15-25 mm in Kandy, Nuwara Eliya, Badulla, Monaragala and Hambantota districts; and up to 5-15 mm most parts of the island.

IMD WRF Model Forecast: 

17th May: Up to 40 mm of rainfall in Ampara and Monaragala districts; and up to 10 mm in Batticaloa, Trincomalee and Mullaitivu districts.

18th May: Up to 160 mm of rainfall in Galle and Ratnapura districts; up to 80 mm Anuradhapura and Polonnaruwa districts; and up to 20 mm in Trincomalee and Ratnapura districts.

IRI Weekly forecast:
From 15th – 20th May: Total rainfall up to 75 mm is expected in Nuwara Eliya and Badulla districts; and up to 50 mm in Polonnaruwa, Matale, Kandy, Kegalle, Ratnapura, Monaragala and Ampara districts.

Ocean State (Text Courtesy IRI)
PACIFIC SEAS STATE : May 9, 2018

SSTs in the tropical Pacific maintained a weak El Niño level during April and early May, while temperature anomalies of subsurface waters decreased but continued to be positive. Patterns in the atmosphere show weak El Niño conditions. Collective model forecasts show a continuation of at least weak El Niño-level SSTs lasting through 2019. The official CPC/IRI outlook, with an El Niño advisory, calls for an approximate 70% chance of El Niño continuing during Jun-Aug, decreasing to 55-60% for Sep-Nov.

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

MJO STATE :  MJO shall suppress the rainfall in Sri Lanka in the next 5 days and shall enhance in the following 10 days.