Climate Bulletin for Sri Lanka ( 19 December 2019)

                                                      Highlights                                

•    The NOAA weekly rainfall forecast predicts up to 200 mm of total rainfall in Batticaloa and Ampara districts during 17- 22 Dec

•     Between 11-16 Dec: up to 60 mm of rainfalls were recorded in Mullaitivu and Vavuniya districts on the 13^th.

•     From 10-16 Dec: up to 36 km/h, easterly 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
11th December	Up to 10 mm in Kalutara and Galle districts.
12th December	Up to 30 mm in Anuradhapura and Vavuniya districts; and up to 20 mm in Jaffna. Kilinochchi, Trincomalee, Polonnaruwa, Ratnapura and Galle districts.
13th December	Up to 60 mm in Mullaitivu and Vavuniya districts; up to 30 mm in Jaffna, Kilinochchi, Mullaitivu, Anuradhapura and Trincomalee districts; and up to 20 mm in Kalutara district.
14th December	Up to 20 mm in Anuradhapura, Kalutara and Galle districts; and up to 10 mm in the rest of the island.
15th December	Up to 10 mm in Monaragala, Batticaloa and Ampara districts.
16th December	Up to 50 mm in Trincomalee, Anuradhapura, Ampara and Batticaloa districts; up to 30 mm in Monaragala district; and up to 20 mm in Badulla district.

Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 75-100 mm in Badulla, Monaragala and Ampara districts; up to 25-50 mm in Batticaloa, Trincomalee, Mullaitivu, Kilinochchi and Jaffna districts; and up to 10-25 mm in most parts of the island. Below-average rainfall up to 100-200 mm is shown for Batticaloa and Ampara districts; up to 50-100 mm in Vavuniya, Mullaitivu, Trincomalee, Polonnaruwa, Batticaloa, Matale, Kandy, Nuwara Eliya, Kegalle, Ratnapura, Kalutara, Galle, Badulla and Monaragala districts; and up to 25-50 mm in rest of the island.

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 18^th – 24^th Dec: Total rainfall more than 135 mm in Trincomalee, Anuradhapura, Polonnaruwa, Badulla, Monaragala, Batticaloa and Ampara districts; up to 115-125 mm in Matale, Kandy, Nuwara Eliya and Hambantota districts; and up to 105-115 mm in Colombo, Ratnapura, Kalutara and Galle districts.
From 25^th – 31^st Dec: Total rainfall more than 135 mm in Batticaloa and Ampara districts; up to 85-95 mm in Trincomalee and Polonnaruwa districts; and up to 75-85 mm in Anuradhapura, Badulla and Monaragala districts

IRI Model Forecast: 
From 17^th – 22^nd Dec: Total rainfall up to 200 mm is expected in Batticaloa and Ampara districts; up to 150 mm Trincomalee, Monaragala, and Hambantota districts; up to 100 mm in Gampaha, Colombo, Mullaitivu, Vavuniya, Anuradhapura and Polonnaruwa 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 in the next 10 days and shall suppress in the following 5 days.

Ocean State (Text Courtesy IRI)

Pacific sea state: December 12, 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 temperature was observed in the seas around Sri Lanka.