Climate Bulletin for Sri Lanka ( 12 December 2019)

                                                      Highlights                                

·         The NOAA weekly rainfall forecast predicts up to 75 mm of total rainfall in northern and south-western regons of the island during 11- 16 Dec.

·         Between 4-10 Dec: up to 160 mm of rainfall was recorded in Trincomalee district on the 9th.

·         From 3-9 Dec: up to 36 km/h, northeasterly winds were experienced by the entire island

·         0.5 0C above-average sea surface temperature was observed in the seas around Sri Lanka.

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Monitoring

Rainfall

Weekly Monitoring:

Date	Rainfall
4th December	Up to 120 mm in Anuradhapura and Vavuniya districts; up to 100 mm in Puttalam district; up to 70 mm in Polonnaruwa, Trincomalee, Mullaitivu, Mannar, Kurunegala, Colombo, Ampara, Badulla, and Monaragala districts; up to 60 mm in Matale and Kandy districts; and up to 50 mm in most parts of the island.
5th   December	Up to 120 mm in Anuradhapura and Trincomalee districts; up to 100 mm in Vavuniya district; up to 70 mm in Jaffna, Kilinochchi, Mannar, Mullaitivu, Polonnaruwa and Trincomalee districts; up to 60 mm in Puttalam and Ampara districts; up to 50 mm in Kurunegala, Gampaha, Kegalle, Badulla and Monaragala districts; up to 30 mm in Matale, Kandy, Ratnapura, Nuwara Eliya, and Colombo districts; and up to 20 mm in Matara and Hambantota districts.
6th  December	Up to 20 mm in Jaffna and Kilinochchi districts.
7th  December	Up to 10 mm in Jaffna, Kilinochchi, Anuradhapura, Matale, Polonnaruwa, Badulla, Monaragala, Ampara and Hambantotoa districts.
8th December	Up to 20 mm in Jaffna, Kilinochchi, Mannar, Puttalam, Batticaloa and Ampara districts.
9th December	Up to 160 mm in Trincomalee district; up to 70 mm in Anuradhapura, Mullaitivu, Vavuniya and Polonnaruwa districts; up to 50 mm in Puttalam, Kurunegala, Batticaloa and Ampara districts; up to 30 mm in Matale and Monaragala districts; and up to 20 mm in Badulla district.
10th December	Up to 70 mm in Colombo and Batticaloa districts; up to 60 mm in Kalutara and Ampara districts; up to 50 mm in Anuradhapura, Trincomalee, Polonnaruwa, Badulla, Monaragala, Puttalam, Gampaha and Galle districts; up to 30 mm in Matale, Kandy, Nuwara Eliya, Kegalle, Ratnapura and Vavuniya districts; and up to 20 mm in most parts of the island.

Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 200-300 mm in Vavuniya, Anuradhapura and Trincomalee districts; up to 150-200 mm in Mannar, Batticaloa, Polonnaruwa and Ampara districts; and up to 100-150 mm in Kilinochchi, Puttalam, Kurunegala, Matale, Kandy, Badulla and Monaragala districts. Above average rainfall up to 200-300 mm is shown for Anuradhapura and Trincomalee districts; and up to 100-200 mm in Vavuniya, Mullaitivu, Puttalam, Polonnaruwa, Batticaloa, Ampara and Monaragala districts.

Monthly Monitoring: During November – Above average rainfall conditions up to 300 mm were experienced by Batticaloa and Ampara districts; up to 240 mm in Gampaha, Colombo, Kalutara, Galle, Kegalle districts and southern regions of Polonnaruwa district; and up to 150 mm in Matale, Badulla, Monaragala, Nuwara Eliya, Ratnapura and Matara districts. Below-average rainfall conditions up to 300 mm were experienced by Vavuniya district; up to 150 mm in Jaffna, Kilinochchi, Mullaitivu and several regions of Mannar, Trincomalee, Anuradhapura, Kandy, Puttalam, Kurunegala and Polonnaruwa districts. The CPC Unified Precipitation Analysis tool shows up to 750 mm were experienced by Batticaloa and Ampara districts; and up to 500 mm in most parts of the island.

Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

IMD NCMWRF Forecast:
From 11^th – 17^th  Dec:  Total rainfall up to 125 mm in Batticaloa and Ampara districts; up to 105-115 mm in Trincomalee, Polonnaruwa, Galle, and Matara districts; and up to 95-105 mm in Colombo, Ratnapura and Hambantota districts.
From 18^th – 24^th Dec: Total rainfall more than 135 mm in Trincomalee, Polonnaruwa, Anuradhapura, Badulla, Monaragala, Batticaloa and Ampara districts; up to 125-135 mm in Jaffna, Kilinochchi and Vavuniya districts; and up to 115-125 mm in Kurunegala and Matale districts.

IRI Model Forecast: 
From 11^th – 16^th Dec: Total rainfall up to 75 mm is expected in Jaffna, Gampaha, Colombo, Kalutara, and Galle districts; and up to 50 mm in most parts of the island.

MJO based OLR predictions:

For the next 15 days: 
MJO shall enhance the rainfall in Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific sea state: November 19, 2019
SSTs in the east-central Pacific were near thresholds of weak El Niño levels during October and early November. However, patterns in most atmospheric variables generally maintained neutral conditions. The oceanic warming is attributed to intraseasonal variability, and the overall diagnosis indicates ENSO-neutral conditions. Most model forecasts favor ENSO-neutral through winter and spring, with slightly higher chances for El Niño than La Niña. The official CPC/IRI outlook is consistent with these model forecasts

Indian Ocean State
0.5 ⁰C above-average sea surface the temperature was observed in the seas around Sri Lanka.