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Friday, December 18, 2020

Climate Bulletin For Sri Lanka (18 December 2020)


   The NOAA weekly rainfall forecast predicts Between 17th-23rd  Dec; up to 140 mm rainfall will be experienced by the Northern province
   Between 10th - 16th Dec: up to 100 mm in Jaffna district on 15th  Dec
•   MJO shall significantly suppress the rainfall during 16th – 30th over Sri Lanka.
   From 9th  - 15th Dec: up to 5 km/h Northeasterly winds were experienced the northern of the island.
   Sea surface temperature was observed above 0.50C to the West of Sri Lanka and neutral to the East



Weekly Monitoring:



10th December

Up to 50 mm in Ratnapura, Kegalle and Kalutara districts.

11th November

Up to 40 mm in Ratnapura, Kalutara and Galle districts.

12th December

No rainfall.

13th December

No rainfall

14th December

Up to 30 mm in Vavuniya, Anuradhapura, Matale and Polonnaruwa districts.

15th December

Up to 100 mm in Jaffna districts.

16th December

Up to 40 mm in Kegalle districts.

Total Rainfall for the Past Week: 
The RFE 2.0 tool shows Cumulative rainfall by Districts:

 50 – 75 mm: Jaffna, Ratnapura, Kegalle, Galle, Kalutara

 25 – 50 mm: Colombo, Gampaha, Matara, Nuwara Eliya, Kandy, Matale, Polonnaruwa, Vavuniya, Kilinochchi                      

 10 - 25 mm: Mullaitivu, Mannar, Anuradhapura, Puttalam, Kurunegala, Moneragala, Hambantota, Ampara, Badulla

   5 – 10 mm: Batticaloa Trincomalee 

Rainfall excess by Districts:

 25 – 50 mm: Jaffna

Rainfall deficit by Districts:

100 – 200mm: Ampara, Moneragala, Batticaloa

  50 – 100mm: Mullaitivu, Vavuniya, Anuradhapura, Polonnaruwa, Trincomalee, Kurunegala, Matale, Kandy, Nuwara Eliya, Ratnapura, Badulla,  Hambantota

 25 – 50 mm : Kilinochchi, Mannar, Puttalam, Kegalle, Gampaha, Colombo, Kalutara, Galle, Matara 

Monthly Monitoring

November is usually the wettest month in Sri Lanka. In Nov 2020, there was a deficit overall which was overcome by the cyclone induced rainfall in the Northern half and the Western Slopes.

During November; Rainfall excess conditions by Districts:

8 mm   : Kurunegala, Puttalam, Badulla, Moneragala, Colombo, Gampaha, Ratnapura

6 mm   : Mullaitivu, Vavuniya, Anuradhapura, Trincomalee, Kegalle, Galle, Matara, Kalutara                

4 mm   : Jaffna, Kilinochchi, Mannar, Matale, Kandy, Nuwara Eliya, Hambantota, Polonnaruwa                

2 mm   : Ampara


Rainfall deficit rainfall by Districts:

4 mm   :  Batticaloa 



14-day prediction: 

NOAA NCEP models: 
            From 17th – 23rd December:

Total rainfall by Provinces:

140 mm   : Northern

135 mm   : Eastern

105 mm   : North-central

  95 mm   : Central Southern Uva

  85 mm   : North-western, Western, Sabaragamuwa 

From 24th – 30th December:

Total rainfall by Provinces:

135 mm  : Northern

 55 mm   : Eastern

 25 mm   : Norther-western, Western 

IRI Model Forecast: 
From 24th – 29th September - Cumulative rainfall by Districts:

 75 mm: Badulla

50 mm: Ampara, Moneragala, Ratnapura, Nuwara Eliya, Kandy, Matale, Polonnaruwa,

                Anuradhapura, Batticaloa, Trincomalee, Vavuniya, Mullaitivu, Kilinochchi, Jaffna

25 mm: Mannar, Puttalam, Kurunegala, Kegalle, Gampaha, Colombo, Kalutara, Galle, Matara,


MJO based OLR predictions:

For the next 15 days: 
MJO shall  suppress the rainfall during 9th – 18th Dec and severely suppress during 19th -23rd Dec over Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific sea state: December 9, 2020 

Equatorial Eastern Pacific SST reached La Niña threshold in early-December, and the atmospheric variables were either ENSO-neutral or indicative of weak La Niña conditions. 

Indian Ocean State

Sea surface temperature was observed above 0.5 0C to the West of Sri Lanka and neutral to the East.

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