Weekly Hydro-meteorological Report, 20, June 2019

Highlights

·  The IRI weekly rainfall forecast predicts up to 100 mm of total rainfall in Western province during 19 – 24 Jun.

·  Between 11 – 17 Jun: up to 50 mm of rainfall was recorded in Colombo district on the 11^th.

·  From 11 – 17 Jun: up to 54 km/h, westerly winds were experienced by the entire island.

·  1 ⁰C above average sea surface temperature was observed in the seas around Sri Lanka.

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Monitoring

Weekly Monitoring: No significant rainfalls were recorded in any part of the island on June 12^th. On June 13^th, Jaffna and Kilinochchi districts received up to 30 mm of rainfall; and Mullaitivu district up to 20 mm.  On the 14^th, Colombo district received up to 30 mm of rainfall; and Puttalam, Gampaha, Kegalle, Ratnapura and Kegalle districts up to 20 mm. No significant rainfalls were recorded in any part of the island on the 15^th. On the 16^th, Kurunegala, Anuradhapura, Matale, Polonnaruwa, Batticaloa, Ratnapura and Matara districts received up to 5 mm of rainfall. On the 17^th, Vavuniya, Batticaloa, Ampara, Monaragala, Badulla, Kegalle, Colombo and Galle districts received up to 5 mm of rainfall.

Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 10-25 mm in Jaffna, Kilinochchi, Mullaitivu, Puttalam, Gampaha, Colombo, Kalutara, Ratnapura, Nuwara Eliya and Batticaloa districts; and 5-10 mm in most parts of the island. Below average rainfall up to 25-50 mm is shown for Kurunegala, Kandy, Nuwara Eliya and Badulla districts; and up to 10-25 mm in most parts of the island.

Monthly Monitoring: During May – Below average rainfall conditions up to 240 mm were experienced by Nuwara Eliya, Kegalle, Colombo, Kalutara, Gampaha, Kurunegala and Ratnapura districts; and up to 180 mm in rest of the island. The CPC Unified Precipitation Analysis tool shows up to 150 mm of total rainfall in Colombo, Kalutara and Galle districts; up to 100 mm in Gampaha, Kegalle, Ratnapura, Matara, Badulla, Monaragala and Galle districts; up to 75 mm in Trincomalee, Polonnaruwa, Nuwara Eliya, Ampara and Hambantota districts; and up to 50 mm in Vavuniya, Anuradhapura, Puttalam, Kurunegala, Matale and Kandy districts. 

Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 19^th – 25^th Jun: Total rainfall up to 55 mm Puttalam, Gampaha, Kegalle, Colombo, Ratnapura and Galle districts; up to 35-45 mm in Kurunegala, Nuwara Eliya and Matara districts; and up to 15-25 mm in most parts of the island.

From 25^th Jun -2^nd Jul: Total rainfall up to 25 mm in Puttalam, Gampaha and Ratnapura districts; and up to 5-15 mm Kurunegala, Kegalle, Galle and Matara districts.

IMD NCMWRF Forecast: 

21^st Jun: Not Available

22^nd Jun: Not Available

IRI Model Forecast: 
From 22nd – 27th May: 

From 19^th – 24^th Jun: Total rainfall up to 100 mm is expected in Gampaha, Colombo and Kalutara districts; up to 75 mm in Puttalam, Kurunegala, Kegalle, Tatnapura and Galle districts; and up to 50 mm in Kandy, Nuwara Eliya, Matara and Hambantota districts.

MJO based OLR predictions:
For the next 15 days:
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. 

Ocean State (Text Courtesy IRI)
Pacific sea state: June 19, 2019

SSTs in the tropical Pacific maintained a weak El Niño level during May and early June, and temperature anomalies of subsurface waters were slightly above average. Some patterns in the atmosphere show intermittent 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 a 66% chance of El Niño continuing during Jun-Aug, decreasing to 50-55% for continuing through fall and winter.

Indian Ocean State

1 ⁰C above average sea surface temperature was observed in the seas around Sri Lanka.