Climate Bulletin For Sri Lanka (24 December 2020)

                        Highlights                             

•   The NOAA weekly rainfall forecast predicts; Dangerously heavy rainfall of 140 mm expected  in Jaffna district and Heavy rainfall in Northern & Eastern Provinces during 30th Dec – 5th Jan.

  •   Extremely high rainfall was experienced in Eastern province. Up to 214 mm max rainfall in Batticaloa on 21st Dec.

•  From 15th - 21st Dec: up to 8 km/h Northeasterly winds were experienced on the entire island.

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

Download full report ↓

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Monitoring

Rainfall

Weekly Monitoring: 

Date	Rainfall
15th December	Up to 80 mm in Jaffna district.
16th December	Up to 40 mm in Kegalle district.
17th December	Up to 50 mm in Anuradhapura, Vavuniya, Kegalle, Nuwara Eliya and Ratnapura districts.
18th December	Up to 50 mm in Jaffna, Kilinochchi, Mullaitivu, Vavuniya, Trincomalee, Anuradhapura, Kegalle, Ratnapura, Galle and Matara districts.
19th December	Up to 90 mm in Polonnaruwa district.
20th December	Up to 70 mm in Batticaloa district.
21st December	Up to 214 mm in Batticaloa district.

Total Rainfall for the Past Week: 

The RFE 2.0 tool shows Cumulative rainfall by Districts:

• 200 – 300 mm - Trincomalee, Polonnaruwa, Batticaloa, Matale
• 150 – 200 mm - Anuradhapura, Kandy, Nuwara Eliya, Kegalle, Badulla, Moneragala, Ampara
• 100 - 150 mm - Kurunegala, Gampaha, Vavuniya, Mannar, Mullaitivu, Kilinochchi 
• 75 – 100 mm - Hambantota, Ratnapura, Kalutara, Colombo, Galle, Puttalam, Jaffna
• 50 - 75 mm    - Matara 

Total rainfall Anomalies by Districts

Rainfall Excess

• 100 – 200 mm - Trincomalee, Polonnaruwa, Batticaloa, Matale, Kandy, Nuwara Eliya, Kegalle, Badulla, Ampara
• 50 – 100 mm   - Vavuniya, Mannar, Mullaitivu, Kilinochchi, Kurunegala, Gampaha, Ratnapura, Moneragala
• 25 - 50 mm     - Colombo, Gampaha, Kalutara, Galle, Puttalam, Jaffna
• 10 – 25 mm    - Hambantota

Monthly Monitoring: 

In the first 10 days in December 2020, there was heavy rainfall was observed in Northern and Western provinces, probably due to cyclone storm “BUREVI”

During December; Dekadal Rainfall by Districts: 

• 18 mm-Jaffna, Kilinochchi, Mullaitivu, Mannar, Trincomalee
• 16 mm- Gampaha, Colombo, Kegalle, Vavuniya, Anuradhapura, Puttalam
• 10 mm- Polonnaruwa, Kurunegala, Batticaloa, Badulla, Moneragala
• 8 mm  - Ratnapura, Matale, Kandy, Nuwara Eliya, Kalutara, Ampara
• 5 mm  - Galle, Matara, Hambantota 

 Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

From 23^rd – 29^th December:

Total rainfall by Provinces: 

140 mm -Northern

55 mm  - Eastern

35 mm  - North-central

25 mm  - Central

15 mm  - North-western, Western, Southern, Sabaragamuwa, Uva 

From 30^th December – 5^thJanuary:

Total rainfall by Provinces:

140 mm - Northern

105 mm - Eastern

95 mm   -  North-central

65 mm   - Central, North-western

55 mm   - Western, Southern, Sabaragamuwa, Uva 

MJO based OLR predictions:

For the next 15 days: 

MJO shall slightly suppress the rainfall during 22^nd – 26^th Dec, neutral during 27^th – 31^st Dec and slightly enhance the rainfall during 1^st – 5^th Jan

Ocean State (Text Courtesy IRI)

Pacific sea state: December 16, 2020 

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

Indian Ocean State

The SST in the Indian Ocean is still warmer by 0.5 degrees than is seasonable to the West of Sri Lanka but near seasonable on the Eastern.

Climate Bulletin For Sri Lanka (18 December 2020)

                        Highlights                             

•   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 16^th – 30^th 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

Download full report ↓

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Monitoring

Rainfall

Weekly Monitoring:

Date	Rainfall
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 

 Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

            From 17^th – 23^rd 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 24^th – 30^th 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,

              Hambantota 

MJO based OLR predictions:

For the next 15 days: 

MJO shall  suppress the rainfall during 9^th – 18^th Dec and severely suppress during 19^th -23^rd 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.

Climate Bulletin For Sri Lanka (11 December 2020)

                        Highlights                             

•   The NOAA weekly rainfall forecast predicts Between 17th-23rd  Dec: very high rainfall over the Northern, North-central and Eastern Provinces.

•   In less than a week after Cyclone Nivar swept past Tamil Nadu and Andhra Pradesh, another cyclone started to brew over the Bay of Bengal 30^th Nov; Burevi was less ferocious than expected in Sri Lanka.

•   Between 3rd - 9th Dec: up to 150 mm in Gampaha district on 8th  Dec.

•   MJO shall suppress the rainfall during 9^th – 18^th Dec and severely suppresses during 19^th -23^rd Dec over Sri Lanka.

•   From  2nd  - 8st Dec: up to 5 km/h distributed winds were experienced the entire island.

•   0.50C above-average sea surface temperature was observed in the seas around Sri Lanka.

Download full report ↓

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Monitoring

Rainfall

Weekly Monitoring:

Date	Rainfall
3rd December	Up to 50 mm in Jaffna district.
4th November	Up to 60 mm in Jaffna district.
5th December	Up to 50 mm in Anuradhapura, Vavuniya and Jaffna districts.
6th December	up to 30 mm in Jaffna district.
7th December	Up to 50 mm in Badulla and Moneragala districts.
8th December	Up to 150 mm in Gampaha and Kurunegala districts.
9th December	No rainfall.

Total Rainfall for the Past Week: 

The RFE 2.0 tool shows total up to 150 – 200 mm in Jaffna and Gampaha districts; up to 100 – 150 mm in Colombo, Kegalle and Mannar districts; up to 75 - 100 mm in Kilinochchi, Mullaitivu, Vavuniya, Anuradhapura, Puttalam, Kurunegala, Kalutara, Ratnapura and Badulla districts; up to 50 – 75 mm in Matale, Kandy, Nuwara Eliya, Moneragala and Trincomalee districts; up to 25 -50 mm Polonnaruwa, Ampara, Batticaloa, Galle and Matara districts; up to 10 – 25 mm in Hambantota district.

Above rainfall average up to 100 – 200 mm in Jaffna, Gampaha, Colombo and Kurunegala districts; up to 50 – 100 mm in Mannar, Anuradhapura, Ratnapura, Kurunegala and Puttalam districts; up to 25 – 50 mm in Kilinochchi, Vavuniya, Mullaitivu, Trincomalee, Kandy, Badulla and Moneragala districts; up to 10 – 25 mm Kalutara, Nuwara Eliya and Matale districts;  Below rainfall average up to 50 – 100 mm in Polonnaruwa district; up to 25 – 50 mm in Batticaloa, Galle, Matara and Hambantota districts and 10 – 25 mm Ampara district.   

          

Monthly Monitoring: 

Overall, November had been wettest as usual. However, as November is the wettest month in Sri Lanka, the rainfall was high. During November; Above average rainfall conditions up to 8 mm in Kurunegala, Puttalam, Badulla, Moneragala, Colombo, Gampaha and Ratnapura districts; up to 6 mm in Mullaitivu, Vavuniya, Anuradhapura, Trincomalee, Kegalla, Galla, Matara, and Kalutara districts; up to 4 mm in Jaffna, Kilinochchi, Mannar, Matale, Kandy, Nuwara Eliya, Hambantota and Polonnaruwa districts; up to 2 mm in Ampara district and Below average rainfall up to 4 mm in Batticaloa district. 

 Predictions

Rainfall

14-day prediction: 

NOAA NCEP models: 

From 10^th – 16^th December: Total rainfall up to 105 mm in Northern province; up to 65 mm in Eastern province; up to 55 mm in Northcentral province and up to 25 mm in Southern, Northwestern, Sabaragamuwa and Western provinces.

From 17^th – 23^rd December: Total rainfall up to 140 mm in Northern, North-central and Eastern provinces; up to 105 mm in Northwestern, Central and Uva provinces; up to 95 mm in Sabaragamuwa and Western provinces and up to 75 mm in Southern province.

IRI Model Forecast: 

From 24^th – 29^th September: Total rainfall up to 75 mm in Badulla district; up to 50 mm in Ampara, Moneragala, Ratnapura, Nuwara Eliya, Kandy, Matale, Polonnaruwa, Anuradhapura, Batticaloa, Trincomalee, Vavuniya, Mullaitivu, Kilinochchi and Jaffna districts; and up to 25 mm in Mannar, Puttalam, Kurunegala, Kegalle, Gampaha, Colombo, Kalutara, Galle, Matara and Hambantota districts. 

MJO based OLR predictions:

For the next 15 days: 

MJO shall  suppress the rainfall during 9^th – 18^th Dec and severely suppress during 19^th -23^rd Dec over Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific sea state: December 2, 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

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