Weekly Hydro-meteorological Report, 23, May 2019

Highlights

• The IRI weekly rainfall forecast predicts up to 75 mm of total rainfall in Kandy, Badulla and Nuwara Eliya districts during 22 – 27 May.
• Between 14 - 21 May: up to 50 mm of rainfall was recorded in Monaragala district on the 16th and 17th.
• From 14 - 20 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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Monitoring

Weekly Monitoring: On May 14th, Kalutara, Galle and Matara districts received up to 10 mm of rainfall. On the 15th, Polonnaruwa, Ampara and Badulla districts received up to 20 mm of rainfall; and Galle and Matara districts up to 10 mm. On the 16th, Badulla, Monaragala and Ampara districts received up to 50 mm of rainfall; Galle, Kandy and Matale districts up to 20 mm; and Kalutara and Polonnaruwa districts up to 10 mm. On the 17th, Badulla, Monaragala and Ampara districts received up to 10 mm of rainfall. On the 18th, Badulla, Monaragala, Ratnapura, Polonnaruwa, Hambantota and Matara districts received up to 20 mm of rainfall; and Kegalle and Ampara districts up to 10 mm. On the 19th, Monaragala district received up to 50 mm of rainfall; Kandy and Colombo districts up to 20 mm; and Kegalle, Ratnapura and Nuwara Eliya districts up to 10 mm. On the 20th, Vavuniya district received up to 30 mm of rainfall; Mullaitivu and Anuradhapura districts up to 20 mm; and Kalutara and Badulla districts up to 10 mm. On the 21st, Jaffna and Kilinochchi districts received up to 10 mm of rainfall

Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 50-75 mm in Badulla and Monaragala districts; up to 25-50 mm in Ampara district; and 10-25 mm in Vavuniya, Anuradhapura, Polonnaruwa, Matale, Kandy, Nuwara Eliya, Kegalle, Gamapaha, Colombo, Kalutara, Ratnapura, Galle and Matara districts. Above average rainfall up to 25-50 mm is shown for Northern regions of Monaragala district; and up to 10-250 mm in Badulla and Vavuniya districts. Below average rainfall up to 50-100 mm is shown for Gampaha, Colombo, Kalutara and Ratnapura districts; up to 25-50 mm in Puttalam, Kurunegala, Kegalle, Nuwara Eliya, Galle, Matara and Hambantota districts; and up to 10-25 mm in Matale, Kandy and Southern regions of Monaragala districts

Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 22nd – 28th May: Total rainfall up to 55 mm Matara and Galle districts; up to 35-45 mm in Ratnapura and Hambantota districts; and up to 25-35 mm in Colombo and Monaragala districts. From 29th May – 4th Jun: Total rainfall up to 75 mm in Ratnapura, Galle and Matara districts; up to 55-65 mm in Kalutara district; up to 35-45 mm in Gampaha, Kegalle and Monaragala districts; up to 25-35 mm in Jaffna, Kilinochchi, Vavuniya and Mullaitivu districts; and up to 5-15 mm most parts of the island.

IMD NCMWRF Forecast: 
24th May: Not Available
25th May: Not Available

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

Total rainfall up to 75 mm is expected in Nuwara Eliya, Kandy and Badulla districts; and up to 50 mm in Polonnaruwa, Matale, Kegalle, Ratnapura, Kalutara, Galle, Matara, Batticaloa, Monaragala and Ampara districts. MJO based OLR predictions For the next 15 days: MJO shall suppress the rainfall in Sri Lanka in the next 5 days and shall enhance in the following 10 days.

MJO based OLR predictions:
For the next 15 days:
MJO shall suppress the rainfall in Sri Lanka in the next 5 days and shall enhance in the following 10 days.

Ocean State (Text Courtesy IRI)
Pacific sea state: May 20, 2018
SSTs in the tropical Pacific maintained a weak El Niño level during April and early May, while temperature anomalies of subsurface waters decreased markedly to just slightly above average. Some 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.