Weekly Hydro-meteorological Report, 22, February 2018

Highlights:

•   The NCEP model predicts total rainfall between 25-35 mm in Kandy, Badulla, Nuwara Eliya, Colombo, Kalutara, Kegalle and Ratnapura districts during 20-26 Feb.
•   Between 12-18 Feb: up to 50 mm of rainfall was recorded in Kegalla and Ratnapura districts on the 15th.
•   From 11-17 Feb:  minimum temperature of 15 ^OC was recorded from Nuwara Eliya district while Kurunegala district recorded a maximum temperature between  30-35 ^OC.
•   From 11-17 Feb: up to 20 km/h, northeasterly winds were experienced by the entire island.
•   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 February 12-13. On February 14th, Welikanda region of Polonnaruwa district received up to 20 mm of rainfall; and coastal regions of Mullaitivu, Trincomalee and Batticaloa districts up to 10 mm. On the 15th, Pussella in Ratnapura district and Eheliyagoda region in Kegalla district received up to 50 mm of rainfall; Nuwara Eliya district up to 30 mm; Gampaha, Colombo, Kandy, Badulla and Monaragala districts up to 20 mm; and Matale Ampara, Kalutara and Galle districts up to 10 mm. No significant rainfalls were recorded in any part of the island during 16-18.  

Total Rainfall for past week :  The RFE 2.0 tool shows total rainfall of 25-50 mm in Kegalla, Ratnapura, and Matara districts; and up to 10-25 mm in Polonnaruwa, Badulla, Gampaha and Colombo districts. It also shows above average rainfall up to 10-25 mm in Kegalla, Ratnapura, and Matara districts. Below average rainfall up to 25-50 mm is shown for Ampara district; and up to 10-25 mm in Batticaloa, Colombo, Kalutara, Galle, Hambantota and Monaragala districts.

Monthly Monitoring: During January - below average rainfall conditions were experienced by the entire island. Trincomalee, Polonnaruwa, Batticaloa, Matale, Colombo, Kalutara, Galle, Ratnapura, Badulla, Monaragala and Ampara districts received up to 180 mm below average rainfall; and rest of the island up to 120 mm. The CPC Unified Precipitation Analysis tool shows ~100 mm of total rainfall in Puttalam, Kalutara, Nuwara Eliya and Badulla districts; and up to ~75 mm in Anuradhapura, Kurunegala, Gampaha, Kegalla, Ratnapura, Galle, Matara, Matale, Kandy, Monaragala and Ampara districts. 

Predictions

14-day prediction:
NOAA NCEP Models:

From 20th-26th Feb: Total rainfall between 25-35 mm in Kandy, Badulla, Nuwara Eliya, Colombo, Kalutara, Kegalle and Ratnapura districts; between 15-25 mm in Mannar, Vavuniya, Anuradhapura, Puttalam, Kurunegala, Matale, Polonnaruwa, Ampara, Monaragala and Gampaha districts; Up to 15 mm of total rainfall rest of the island.

From 27th Feb-5th Mar: Total rainfall between 5-15 mm in Gampaha, Colombo, Kegalle, Kandy, Nuwara Eliya, Badulla, Ratnapura and Kalutara districts; Up to 5 mm total rainfall rest of the island.

IMD WRF Model Forecast: 

23rd Feb: Up to 7.6 mm of rainfall in Batticaloa, Ampara and Monaragala districts; Up to 2.5 mm in Kilinochchi, Mullaitivu, Mannar, Vavuniya, Puttalam, Anuradhapura, Trincomalee, Polonnaruwa, Badulla, Hambantota and Colombo districts.

24th Feb: Up to 7.6 mm of rainfall in Kilinochchi, Mullaitivu, Vavuniya, Anuradhapura, Trincomalee, Polonnaruwa, Batticaloa, Ampara, Monaragala and Hambantota districts; Up to 2.5 mm in Jaffna, Mannar, Puttalam, Kurunegala,  Matale, Kandy, Badulla, Gampaha, Colombo and Kalutara districts.

IRI Weekly forecast:
From 21st–26th Feb: Total rainfall between 25-50 mm in Kilinochchi, Mullaitivu, Vavuniya, Anuradhapura, Trincomalee, Polonnaruwa, Batticaloa, Ampara, Monaragala, Hambantota, Badulla, Ratnapura, Nuwara Eliya, Kandy, Matale, Kurunegala, Kegalle, Gampaha, Colombo and Kalutara districts; Up to 25 mm total rainfall rest of the island.


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

In mid-February 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 key atmospheric variables showing patterns suggestive of La Niña conditions. The official CPC/IRI outlook calls for La Niña continuing through at least early spring, followed by a likely return to neutral conditions around mid-spring. Support for this scenario is provided by the latest forecasts of statistical and dynamical models.

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

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