Weekly Hydro-meteorological Report, 26, January 2018

Highlights:

•   The IRI Model predicts total rainfall between 50-75 mm in Batticaloa and Ampara districts during 24th -29th Jan.
•   Between 17-21 Jan: No significant rainfalls were recorded in any part of the island.
•   From 14-20 Jan:  minimum temperature of 15 ^OC was recorded from Nuwara Eliya district while western and southern parts of the island recorded a maximum temperature between  30-35 ^OC.
•   From 16-22 Jan: up to 18 km/h, northeasterly winds were experienced by the entire island.
•   0.5 ^OC below average sea surface temperature was observed in the northern seas of Sri Lanka.

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Summary

Monitoring

Weekly Monitoring: No significant rainfalls were recorded in any part of the island during 17th- 21st Jan. On January 22nd several regions of Nuwara Eliya, Batticaloa and Monaragala districts received up to 10 mm of rainfall. On the 23rd, Kurunegala, Anuradhapura, Matale and Polonnaruwa districts received up to 10 mm of rainfall. 

Total Rainfall for past week :  The RFE 2.0 tool shows total rainfall of 5-10 mm in Kurunegala, Anuradhapura, Batticaloa, Ratnapura, Badulla and Monaragala districts. It also shows below average rainfall up to 10-25 mm in Mullaitivu, Vavuniya, TRincomalee, Anuradhapura, Batticaloa, Ampara, Nuwara Eliya, Kalutara and Galle districts.

Monthly Monitoring: During December - below average rainfall conditions were experienced by the entire island except for several regions of Ratnapura, Badulla, Monaragala and Hambantota districts. Mullaitivu, Vavuniya, Anuradhapura, Trincomalee, Polonnaruwa, Batticaloa and Ampara districts received up to 180 mm below average rainfall; and Gampaha, Jaffna, Kilinochchi, Mannar, Puttalam, Kurunegala, Kandy and Galle districts received up to 150 mm. The CPC Unified Precipitation Analysis tool shows ~300 mm of total rainfall in Badulla, Monaragala and Ratnapura districts; up to ~200 mm in Nuwara Eliya and Ratnapura districts; and Anuradhapura, Puttalam, Kurunegala, Gampaha, Kegalla, Matale, Galle, Matara, Polonnaruwa, Trincomalee and Ampara districts up to 100 mm.

Predictions

14-day prediction:
NOAA NCEP Models:

From 24th Jan – 30thJan: Total rainfall between 45-55 mm in Ampara, Monaragala and Hambantota districts; between 35-45 mm in Badulla, Batticaloa, Nuwara Eliya and Ratnapura districts; between 25-35 mm in Matara, Kandy, Matale and Polonnaruwa districts; between 15-25 mm in Trincomalee, Anuradhapura, Kurunegala, Kegalle, Colombo and Galle districts; Up to 15 mm total rainfall rest of the island.

From 31st Jan– 06th Feb: Total rainfall between 25-35 mm in Kalutara, Galle, Matara, Hambantota and Ratnapura districts; between 15-25 mm in Gampaha, Colombo, Kegalle, Kandy, Nuwara Eliya, Badulla, Ampara and Monaragala districts; between 5-15 mm in Puttalam, Kurunegala and Matale districts; Up to 5 mm total rainfall rest of the island.

IMD WRF Model Forecast: 

26th Jan: Up to 7.6 mm of rainfall in Kilinochchi, Mullaitivu, Vavuniya, Anuradhapura, Trincomalee, Ampara and Monaragala districts; Up to 2.5 mm in Mannar, Puttalam, Kurunegala, Polonnaruwa, Batticaloa, Gampaha and Colombo districts.

27th Jan: Up to 7.6 mm of rainfall in Kilinochchi, Mullaitivu, Vavuniya and Anuradhapura districts; Up to 2.5 mm in Jaffna, Mannar, Puttalam, Kurunegala, Matale, Kandy, Gampaha, Colombo, Kalutara, Hambantota and Badulla districts.

IRI Weekly forecast:
24th – 29th Jan: Total rainfall between 50-75 mm in Batticaloa and Ampara districts; between 25-50 mm in Mullaitivu, Vavuniya, Anuradhapura, Trincomalee, Polonnaruwa, Ampara, Hambantota, Monaragala, Badulla, Ratnapura, Nuwara Eliya, Kandy, Matale, Gampaha, Colombo and Kalutara districts; Up to 25 mm total rainfall rest of the island.


Ocean State (Text Courtesy IRI)
PACIFIC SEAS STATE : January 19, 2017

In mid-January 2018, the tropical Pacific reflected La Niña conditions, with SSTs in the east-central tropical Pacific in the range of weak to moderate La Niña and most atmosphere variables showing patterns suggestive of La Niña conditions. The collection of latest ENSO prediction models indicates weak La Niña continuing through the Northern Hemisphere winter and early spring, followed by a return to neutral conditions during spring. This scenario is consistent with the official CPC/IRI outlook, which continues its La Niña advisory.

INDIAN OCEAN STATE :   0.5 ⁰C below average sea surface temperature was observed in the northern seas of Sri Lanka.

MJO STATE :  MJO shall suppress the rainfall in Sri Lanka.