Weekly Hydro-meteorological Report, 4, January 2018

Highlights:

•   The NCEP weekly rainfall forecast predicts between 75-85 mm of rainfall in Monaragala, Ampara, Badulla and Hambantota districts during 10th-16th Jan.
•   Between 26 Dec- 1 Jan: Rainfall up to 60 mm was recorded in Hambantota, Nuwara Eliya, Ratnapura and Badulla districts on December 26th.
•   From 24- 30 Dec:  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 26 Dec- 1 Jan: up to 18 km/h, northeasterly winds were experienced by the entire island.
•   Average sea surface temperature was observed in the southern seas of Sri Lanka.

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Summary

Monitoring

Weekly Monitoring: On December 26th, Ratnapura district received up to 50 mm of rainfall; Badulla, Hambantota, and Ampara districts received up to 30 mm; and Mannar, Puttalam, Anuradhapura, Kurunegala, Batticaloa, Kegalla and Kalutara districts up to 20 mm; Batticaloa, Polonnaruwa, Gampaha, Colombo, Kalutara, Matara, Matale and Kandy districts up to 30 mm; Mannar, Vavuniya, Anuradhapura, Puttalam, Kurunegala, Trincomalee and Galle districts up to 20 mm. On the 27th Monaragala and Ampara districts received up to 30 mm of rainfall; and Kegalla, Ratnapura, Kalutara, Galle, Matara, Nuwara Eliya, Badulla and Hambantota districts up to 10 mm. Ratnapura, Kalutara, Galle and Matara districts received up to 10 mm of rainfall on 28th and 29th.  On the 30th, Ratnapura, Badulla, Monaragala, Hambantota and Ampara districts received up to 10 mm. No significant rainfalls were recorded in any part of the island during 31st Dec- 1st Jan. 

Total Rainfall for past week :  The RFE 2.0 tool shows total rainfall of 25-50 mm in Badulla district; and up to 10-25 mm in Monaragala, Ratnapura, Galle and Matara districts. It also shows below average rainfall up to 50-100 mm in Ampara district; up to 25-50 mm in Kilinochchi, Vavuniya, Anuradhapura, Polonnaruwa, Batticaloa, Badulla and Monaragala districts; and up to 10-25 mm in rest of the island.

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 03rd – 09th Jan: Total rainfall between  15-25 mm in Badulla, Monaragala and Ampara districts; between 5-15 mm in Colombo, Kegalle, Kandy, Kalutara, Ratnapura, Galle Matara, Hambantota and Nuwara Eliya districts; Up to 5 mm total rainfall rest of the island.

From 10th – 16th Jan: Total rainfall between 75-85 mm in Monaragala, Ampara, Badulla and Hambantota districts; between 55-65 mm in Matara, Ratnapura, Nuwara Eliya and Kandy districts; between 45-55 mm in Galle and Batticaloa districts; between 35-45 mm in Colombo, Kegalle, Matale and Polonnaruwa districts; between 25-35 mm in Gampaha and Kurunegala districts; between 15-25 mm in Puttalam, Anuradhapura and Trincomalee districts; Up to 5 mm total rainfall rest of the island.

IMD WRF Model Forecast: 

05th Jan: Up to 7.6 mm of rainfall in Hambantota, Monaragala, Ampara, Batticaloa, Polonnaruwa, Vavuniya and Mullaitivu districts; Up to 2.5 mm in Galle, Matara, Gampaha, Colombo, Kalutara, Badulla, Matale, Kurunegala, Puttalam, Anuradhapura, Trincomalee and Mannar districts.

06th Jan: Up to 7.6 mm of rainfall in Monaragala, Ampara, Kilinochchi, Mullaitivu and Mannar districts; Up to 2.5 mm in Kalutara, Galle, Hambantota, Badulla, Matale, Kurunegala, Puttalam, Anuradhapura, Polonnaruwa, Batticaloa, Trincomalee and Vavuniya districts.

IRI Weekly forecast:
03rd – 08th Jan: Total rainfall up to 25 mm over Sri Lanka.


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

In mid-December 2017, 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 all atmosphere variables showing patterns suggestive of La Niña conditions. The collection of latest ENSO prediction models indicates weak, but not far from threshold of moderate, La Niña as the most likely scenario for the Northern Hemisphere winter, lasting into spring. The official CPC/IRI outlook favors continuation of La Niña through middle or late spring.

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

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