Weekly Hydro-meteorological Report, 8, March 2018

Highlights:

•   The IRI weekly forecast predicts total rainfall between 75-100 mm in Ampara and Monaragala districts during 7th-12th Mar.  
•   Between 27 Feb- 5 Mar: up to 140 mm of rainfall was recorded in Batticaloa district on the 27th.
•   From 25 Feb- 3 Mar:  minimum temperature of 15 ^OC was recorded from Nuwara Eliya district while Kurunegala  district  recorded a maximum temperature between  30-35 ^OC.
•   From 27 Feb- 5 Mar: up to 22 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 February 27th, Batticaloa district received up to 140 mm of rainfall; Ampara and Badulla districts up to 100 mm; Trincomalee and Polonnaruwa districts up to 70 mm; Mullaitivu, Kalutara, Galle, Matara and Ratnapura districts up to 50 mm; Vavuniya, Anuradhapura, Hambantota and Kandy districts up to 30 mm; and Kilinochchi, Mannar, Kurunegala, Colombo, Kegalla and Nuwara Eliya districts up to 20 mm. On the 28th, Gampaha and Kegalla districts received up to 90 mm of rainfall; Colombo, district up to 50 mm; Trincomalee, Matale, Kurunegala and Kalutara districts up to 30 mm; and Puttalam, Polonnaruwa, Anuradhapura, Nuwara Eliya and Galle districts up to 20 mm. On March 1st, Nuwara Eliya and Badulla districts received up to 30 mm; and Ratnapura and Galle districts up to 20 mm. On the 2nd, Gampaha, Colombo, Kalutara, Galle, Matara, Kegalla, Ratnapura and several regions of Kurunegala and Nuwara Eliya districts received up to 10 mm of rainfall. On the 3rd, Colombo district received up to 70 mm of rainfall; Kalutara district up to 30 mm; and Gampaha, Kurunegala, Kegalla, Ratnapura and Galle districts up to 20 mm. On the 4th, Galle district received up to 30 mm of rainfall; and Matara, Ratnapura and Hambantota districts up to 20 mm. On the 6th, Kalutara and Galle districts received up to 30 mm of rainfall; and Ratnapura, Matara and several regions of Matale, Kandy, Nuwara Eliya and Kegalla districts received up to 10 mm.

Total Rainfall for past week :  The RFE 2.0 tool shows total rainfall of 50-75 mm in Gampaha, Colombo, Kegalla, Galle and Kalutara districts; and up to 25-50 mm in Matara and Ratnapura districts. It also shows above average rainfall up to 50-100 mm in Galle and Kalutara districts; and up to 25-50 mm in Colombo, Gampaha and Kegalla districts. Below average rainfall up to 25-50 mm is shown for Anuradhapura, Puttalam, Kurunegala, Matale, Kandy, Polonnaruwa, Batticaloa, Ampara, Badulla and Monaragala 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 7th-13th Mar: Total rainfall between 45-55 mm in Batticaloa and Ampara districts; between 35-45 mm in Trincomalee, Polonnaruwa and  Monaragala districts; between 25-35 mm in Badulla, Hambantota, Galle and Matara districts; between 15-25 mm in Anuradhapura, Matale, Kandy, Nuwara Eliya, Ratnapura, Kalutara, Colombo and Gampaha districts; Up to 15 mm of total rainfall rest of the island.

From 14th–20th Mar: Total rainfall between 25-35 mm in Trincomalee and Batticaloa districts; between 15-25 mm in Polonnaruwa and Ampara districts; Up to 15 mm of total rainfall rest of the island.

IMD WRF Model Forecast: 

9th Mar: Up to 7.6  mm of rainfall in Monaragala, Ampara and Hambantota districts; Up to 2.5 mm of rainfall in Jaffna, Mullaitivu, Mannar, Vavuniya, Trincomalee, Anuradhapura, Polonnaruwa, Batticaloa, Matara, Galle, Kalutara, Colombo, Gampaha, Puttalam and Kurunegala  districts.

10th Mar: Up to 35.6 mm of rainfall in Ampara and Batticaloa districts; Up to 7.6 mm in Kilinochchi, Mullaitivu, Vavuniya, Anuradhapura, Trincomalee, Polonnaruwa, Matale, Kandy, Kegalle, Badulla, Monaragala and Hambantota districts; Up to 7.6 mm of rainfall in rest of the island.

IRI Weekly forecast:
From 7th-12th  Mar: Total rainfall between 75-100 mm in Ampara and Monaragala districts; between 50-75 mm in Batticaloa, Badulla, Hambantota, Ratnapura, Nuwara Eliya, Kandy, Kegalle, Gampaha, Colombo and Kalutara districts; between 25-50 mm in   Trincomalee, Polonnaruwa, Matale, Kurunegala and Puttalam 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 seas around Sri Lanka.

MJO STATE :  MJO shall enhance the rainfall in Sri Lanka in the next 5 days; shall not have an effect on the following 5 days; and shall suppress the rainfall in the next 5 days.