Weekly Hydro-meteorological Report, 22, March 2018

Highlights:

•   The IRI weekly forecast predicts total rainfall between 25-50 mm in Kandy, Kegalle, Nuwara Eliya, Badulla, Monaragala, and Ratnapura districts during 21st - 26th Mar.
•   Between 13- 19 Mar: up to 80 mm of rainfall was recorded in Kilinochchi district on the 13th.
•   From 11- 17 Mar:  minimum temperature of 15 ^OC was recorded from Nuwara Eliya district while Kurunegala, Puttalam and Kegalla districts   recorded a maximum temperature between  30-35 ^OC.
•   From 13- 19 Mar: up to 18 km/h, easterly winds were experienced by the entire island.
•   Average sea surface temperature was observed in the seas around Sri Lanka.

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Summary

Monitoring

Weekly Monitoring: On March 13th, Kilinochchi district received up to 80 mm of rainfall; Jaffna and Mullaitivu districts up to 30 mm; Galle district up to 20 mm; and Gampaha, Colombo, Kalutara, Matara and several regions of Vavuniya, Ratnapura and Hambantota districts up to 10 mm. On the 14th, Jaffna, Mannar, Puttalam, Badulla and Monaragala districts received up to 20 mm of rainfall; and Nuwara Eliya, Matara and several regions of Kilinochchi, Mullaitivu, Vavuniya, Anuradhapura, Kurunegala, Kegalla, Ratnaprura, Hambantota, Matale, Kandy districts up to 10 mm. On the 15th, Anuradhapura and Kurunegala districts received up to 70 mm of rainfall; Puttalam, Matale, Kandy and Badulla districts up to 50 mm; Jaffna, Mullaitivu, Vavuniya districts and southern regions of Polonnaruwa district up to 30 mm; and Kilinochchi, Mannar, Gampaha, Kegalla and Nuwara Eliya districts up to 20 mm. On the 16th, Kurunegala and Kegalla districts received up to 50 mm of rainfall; Kandy district up to 30 mm; Anuradhapura and Gampaha districts up to 20 mm; and many parts of the island up to 10 mm. On the 17th, Kalutara district received up to 20 mm of rainfall; and Colombo, Gampaha, Kegalla, Ratnapura, Galle and Matara districts up to 10 mm. On the 18th, Colombo, Kalutara and Galle districts received up to 10 mm. On the 19th, Gampaha, Colombo, Kalutara and Ratnapura districts received up to 20 mm; and Gampaha, Kegalla, Galle and Matara districts received up to 10 mm.

Total Rainfall for past week :  The RFE 2.0 tool shows total rainfall of 75-100 mm in Kurunegala district; up to 50-75 mm in Anuradhapura district; and up to 25-50 mm in Vavuniya, Matale, Kandy, Kegalla and Badulla districts. It also shows above average rainfall up to 50-100 mm in Kurunegala and Anuradhapura districts; and up to 25-50 mm inBadulla district. Below average rainfall up to 25-50 mm is shown for Ratnapura,  Galle, Matara, Hambantota and Ampara districts.

Monthly Monitoring: During February - below average rainfall conditions were mainly experienced by northern and southeastern regions of the island. Jaffna, Vavuniya, Mullaitivu, Mannar, Trincomalee, Anuradhapura, Kandy, Nuwara Eliya and southern regions of Badulla, Monaragala and Ampara districts received up to 150 mm below average rainfall. Above average rainfall up to 150 mm was received by northern regions of Ampara, Badulla and Monaragala districts; and up to 120 mm by Gampaha, Batticaloa and Matara districts. The CPC Unified Precipitation Analysis tool shows ~100 mm of total rainfall in Matara, Ratnapura, Nuwara Eliya, Kegalla, Kurunegala, Polonnaruwa, Matale, Kandy, Badulla, Monaragala, Ampara and Gampaha districts; and up to ~75 mm in Mullaitivu, Anuradhapura, Puttalam, Colombo and Hambantota districts. 

Predictions

14-day prediction:
NOAA NCEP Models:

From 20th-26th Mar: Total rainfall between 25-35 mm in Batticaloa and Ampara districts; between 15-25 mm in Trincomalee and Polonnaruwa districts; between 5-15 mm in Galle Matara and Monaragala districts; Up to 5 mm total rainfall rest of the island.

From 27th Mar- 02nd Apr: Total rainfall between 35-45 mm in Batticaloa and Ampara districts; between 25-35 mm in Trincomalee, Polonnaruwa, Galle and Matara districts; between 15-25 mm in Monaragala and Hambantota districts; between 5-15 mm in Anuradhapura, Matale, Kandy, Nuwara Eliya, Badulla, Ratnapura, Kalutara and Colombo districts; Up to 5 mm total rainfall rest of the island.

IMD WRF Model Forecast: 

23rd Mar: Up to 7.6 mm of rainfall in Mullaitivu, Vavuniya, Anuradhapura, Puttalam, Kurunegala and Polonnaruwa districts; Up to 2.5 mm in Jaffna, Kilinochchi, Mannar, Trincomalee, Batticaloa, Ampara, Hambantota, Matara, Galle, Kalutara, Colombo, Gampaha districts.

24th Mar: Up to 2.5 mm of rainfall in Jaffna, Kilinochchi, Mullaitivu, Mannar, Vavuniya, Puttalam, Anuradhapura, Trincomalee, Polonnaruwa, Batticaloa, Ampara, Monaragala, Hambantota and Colombo districts.

IRI Weekly forecast:
From 21st -26th Mar: Total rainfall between 25-50 mm in Kandy, Kegalle, Nuwara Eliya, Badulla, Monaragala and Ratnapura districts; Up to 25 mm of total rainfall rest of the island.


Ocean State (Text Courtesy IRI)
PACIFIC SEAS STATE : March 19, 2018

In mid-March 2018, the east-central tropical Pacific still reflected weak La Niña conditions. Most of the key atmospheric variables, however, no longer show patterns suggestive of La Niña, and the east Pacific subsurface water temperature has warmed back to average. The official CPC/IRI outlook calls for a transition from La Niña to neutral conditions during the March-May season. The latest forecasts of statistical and dynamical models support this scenario.

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

MJO STATE :  MJO shall not have an effect on the rainfall.