Climate Bulletin For Sri Lanka (28 May 2021)

 

Highlights          

                   

  •   Showers of 125 mm expected in Western, Sabaragamuwa during 28th May – 2nd June and  145 mm North Western, Western, Sabaragamuwa, Southern in 3rd  - 9th  June  

  •   Last week was wetter than normal in most of SL.  Thunder showers in Central province with a maximum of  188.5 mm in Kandy on 24th May

•  From 19th  - 25th May: up to 15 km/h from the West and South were experienced. Due to a deep depression located in East Central Bay of Bengal that intensified into a cyclonic storm (“YAAS”) on May 24th around 05:30 a.m.

•  Sea surface temperature was observed around 0.5℃ above average around the island. The SST in the Arabian Sea has dropped after the heavy rainfall last week.

•  The SST forecast indicates that the La Niña event has transitioned to ENSO-neutral. 

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Monitoring

Rainfall
Total Rainfall for the Past Week: 

The RFE 2.0 tool shows Cumulative rainfall by Districts:

• 150 – 200 mm - Puttalam, Kurunegala, Kegalle, Ratnapura, Gampaha, Kandy, Kalutara
• 100 – 150 mm - Kandy, Nuwara Eliya, Galle, Matara 
• 75 – 100 mm - Badulla, Moneragala, Hambantota
• 50 – 75 mm - Jaffna, Kilinochchi, Mannar, Vavuniya, Mullaitivu, Anuradhapura, Polonnaruwa, Trincomalee, Batticaloa, Matale
• 25 – 50 mm - Ampara
  

Weekly rainfall Anomalies by Districts

Rainfall Excess

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

Monthly Monitoring: 

Dekadal Rainfall by Districts:

1^st – 10^th May:

• 16 mm - Gampaha, Colombo, Kalutara, Galle, Matara, Hambantota, Kegalle, Ratnapura, Nuwara Eliya, Kandy, Matale, Badulla, Moneragala, Anuradhapura, Mannar, Vavuniya, Mullaitivu, Puttalam, Kurunegala
• 14 mm - Ampara, Kilinochchi
• 12 mm - Polonnaruwa
• 6 mm- Batticaloa, Trincomalee
• 4 mm  - Jaffna

11^th – 20^th May:

• 14 mm Puttalam, Kurunegala, Gampaha, Colombo 
• 12 mm Kalutara, Ratnapura, Kegalle
• 10 mm Galle, Matara
• 8 mm Jaffna, Kilinochchi, Polonnaruwa, Trincomalee, Batticaloa, Ampara, Badulla, Moneragala, Kandy, Nuwara Eliya, Hambantota 
• 6 mm Mullaitivu, Vavuniya, Anuradhapura, Matale
• 4 mm Mannar

Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 28^th May – 2^nd June: 

Total rainfall by Provinces: 

• 125 mm - Western, Sabaragamuwa
• 115 mm - North Western, Southern
• 95 mm  - Central
• 55 mm  - Uva
• 45 mm  - North Central, Eastern
• 25 mm  -Northern

From 3^rd – 9^th June: 

Total rainfall by Provinces:

• 145 mm - North Western, Western, Sabaragamuwa, Southern
• 125 mm - Central
• 95 mm  - Uva
• 85 mm  - North Central, Eastern
• 65 mm  - Northern

MJO based OLR predictions:

For the next 15 days: 

 MJO shall slightly suppressed the rainfall during 26^th May –4^th June and significantly suppressed the rainfall during 5^th– 9^th June.

Ocean State (Text Courtesy IRI)

Pacific sea state: May 12, 2021 

Equatorial SSTs were mostly below average from the east to the Middle West Pacific Ocean in mid May and most key atmospheric variables were either ENSO –Neutral or consistent with continued La Niña conditions. A large majority of the model forecasts predict SSTs to be cooler than the threshold of La Niña SST conditions through the winter, dissipating during spring.

Indian Ocean State

Sea surface temperature was observed around 0.5℃ above average around the island. The SST in the Arabian Sea has dropped after the heavy rainfall last week.