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Monday, November 28, 2022

Climate Bulletin For Sri Lanka (25 November 2022)

      

Highlights          


 • Moderately heavy (≥ 40 mm) rainfall is predicted for the Sabaragamuwa, Uva, and Eastern provinces during 24th - 30th November.
 • During the last week, the average daily rainfall over Sri Lanka was 0.8 mm & hydro catchment areas received 0.8 mm on average and the highest average rainfall (1.6 mm) was received to the Eastern plains of the country.
 • From 14th - 20th Nov, up to 6m/s of north-easterly winds were experienced at 850 mb level over the island. Wind Direction has changed from arriving from South-West to arriving from North East.
 • Sea surface temperature around Sri Lanka was above normal to the Southern half of the country. Land surface temperature remained near normal.



Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 24th November – 30th November:
Total rainfall by Provinces:   
  •   70 mm - Uva, Sabaragamuwa
  •   40 mm - Eastern
  •   20 mm - Southern, Central, North Western, North Central
  • ≤ 10 mm - Northern, Western
MJO based OLR predictions:
For the next 15 days: 
MJO shall moderately suppress the rainfall during 23rd – 27th November, slightly suppress the rainfall during 28th November – 2nd December, and remain near normal during 3rd – 7th December for Sri Lanka.

Ocean State (Text Courtesy IRI)
Pacific Sea Sate: November 21, 2022 
Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean late - November. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate La Niña is favored to continue through during the Northern Hemisphere winter (December-February) 2022-23, with a transition to ENSO-neutral favored in February-April 2023 (57% chance).

Indian Sea Sate
Sea surface temperature around Sri Lanka was above 0.5℃ to the Southern half of the country in 16th November, 2022. Across the Indian Ocean, a classical negative Indian Ocean Dipole prevails as is typical during a La Niña.

 

Interpretation


Monitoring
Rainfall: 
During the last two weeks, there had been very heavy rainfall over the following areas: Kegalle, Avissawella

Daily Average Rainfall in the Met stations for previous week of (15th November – 22nd November) = 0.8 mm

Rmax: 30.5 mm & Rmin: 0.0 mm.


Region

Average rainfall for the Last 8 days

Northern Plains

0.0 mm

Eastern

1.6 mm

Western

0.5 mm

Southern Plains

0.8 mm


The Hydro Catchment Areas recorded 0.8 mm of average rainfall for the last week

Rmax: 14.8 mm & Rmin: 0.0 mm.


Wind:
North-easterly winds prevailed in the sea area and around the island last week.
Temperature: 
The temperature anomalies were below normal for some parts of the North Central, North Eastern and Central provinces, driven by the warm SST’s.

Predictions
Rainfall:
During the next week (24th – 30th November), moderately heavy (≥ 40 mm) rainfall is predicted for the Uva, Sabaragamuwa, and Eastern provinces; and less rainfall is expected for the rest of the country.
Temperature:
The temperature will remain below normal for some parts of the Central and Uva provinces during 24th – 30th November.
Teleconnections:
La Niña is favored to continue through during the Northern Hemisphere winter (December-February) 2022-23, with a transition to ENSO-neutral favored in February-April 2023 (57% chance).
MJO shall moderately suppress the rainfall during 23rd – 27th November, slightly suppress the rainfall during 28th November – 2nd December, and remain near normal during 3rd – 7th December for Sri Lanka.

Seasonal Precipitation: 
The precipitation forecast for the December-January-February 2023 season shows a higher tendency for near-normal precipitation to the country. 

Friday, November 18, 2022

Climate Bulletin For Sri Lanka (18 November 2022)

     

Highlights          


 • Fairly heavy (≥ 55 mm) rainfall is predicted for the Sabaragamuwa, Southern, Northern, Western, and Central provinces during 16th - 22nd November.
 • During the last week, the average daily rainfall over Sri Lanka was 14.4 mm & hydro catchment areas received 9.4 mm on average and the highest average rainfall (17 mm) was received to the Eastern and Southern plains of the country.
 • From 7th - 13th Nov, up to 6m/s of north-easterly winds were experienced at 850 mb level over the island. During 17th - 23rd Nov, north - westerly winds are expected to the country .
 • Sea surface temperature around Sri Lanka was above normal to the Southern half of the country. Land surface temperature remained near normal.



Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 16th November– 22nd November:
Total rainfall by Provinces:   
  •   85 mm - Southern, Sabaragamuwa
  •   75 mm - Northern, Western
  •   55 mm - Central
  •   25 mm - Eastern, Uva
  • < 25 mm - North Western, North Central
MJO based OLR predictions:
For the next 15 days: 
MJO shall moderately suppress the rainfall during 16th– 25th November and slightly suppress the rainfall during 26th – 30th November for Sri Lanka.

Ocean State (Text Courtesy IRI)
Pacific Sea Sate: November 14, 2022 
Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean mid - November. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate La Niña is favored to continue through during the Northern Hemisphere winter (December-February) 2022-23, with a transition to ENSO-neutral favored in February-April 2023 (57% chance).

Indian Sea Sate
Sea surface temperature around Sri Lanka was above 0.5℃ to the Southern half of country in 9th November, 2022. Across the Indian Ocean, a classical negative Indian Ocean Dipole prevails as is typical during a La Niña.

 

Interpretation


Monitoring
Rainfall: 
During the last two weeks, there had been very heavy rainfall over the following areas: Kegalle, Jaffna, and Avissawella

Daily Average Rainfall in the Met stations for previous week of (8th November – 15th November) = 14.4 mm

Rmax: 133.9 mm & Rmin: 0.0 mm.


Region

Average rainfall for the Last 8 days

Northern Plains

14.8 mm

Eastern

17.3 mm

Western

12.5 mm

Southern Plains

17.9 mm


The Hydro Catchment Areas recorded 9.4 mm of average rainfall for the last week
Rmax: 92.9 mm & Rmin: 0.0 mm. 

Wind:
North-easterly winds prevailed in the sea area and around the island last week. 
Temperature: 
The temperature anomalies were below normal for the North Central province and some parts of the North Eastern, Eastern and Central provinces, driven by the warm SST’s.

Predictions
Rainfall:
During the next week (16th – 22nd November), fairly heavy (≥ 55 mm) rainfall is predicted for the Southern, Sabaragamuwa, Northern, Western, and Central provinces; and less rainfall is expected for the rest of the country.
Temperature:
The temperature will remain below normal for some parts of the Central and Uva provinces during 17th – 23rd November.
Teleconnections:
La Niña is favored to continue through during the Northern Hemisphere winter (December-February) 2022-23, with a transition to ENSO-neutral favored in February-April 2023 (57% chance).
MJO shall moderately suppress the rainfall during 16th– 25th November and slightly suppress the rainfall during 26th – 30th November for Sri Lanka.

Seasonal Precipitation: 
The precipitation forecast for the December-January-February 2023 season shows a higher tendency for above-normal precipitation in the north half of the country.

Friday, November 11, 2022

Climate Bulletin For Sri Lanka (11 November 2022)

    

Highlights          


 • Heavy rainfall (≥135mm) is predicted for the Sabaragamuwa, Western, Northern, and Southern provinces during 9th - 15th Nov. During 10th - 22nd Nov heavy rainfall is predicted for Southern and Sabaragamuwa provinces.
 • During the last week, the average daily rainfall over Sri Lanka was 16.8 mm & hydro catchment areas received 15.3 mm on average.
 • From 31st Oct  -6th Nov, up to 5m/s of north-westerly and north-easterly winds were experienced at 850 mb level over the island. During 10th - 16th Nov, westerly winds are expected to the country .
 • Sea surface temperature around Sri Lanka was above normal to the whole country in late - October. Land surface temperature remained near normal.



Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 9th November– 15th November:
Total rainfall by Provinces:   
  • > 135 mm - Western, Southern, Northern, Sabaragamuwa
  •    135 mm - Eastern, Central
  •    125 mm - North Western, North Central, Uva
From 16th November– 22nd November:
Total rainfall by Provinces:
  • > 135 mm - Southern
  •   135 mm - Sabaragamuwa
  •   115 mm - Western
  •    85 mm - Northern, Central, Uva
  •    65 mm - Eastern, North Western
  •    55 mm - North Central
MJO based OLR predictions:
For the next 15 days: 
MJO shall near neutral the rainfall during 9th– 23rd November for Sri Lanka.

Ocean State (Text Courtesy IRI)
Pacific Sea Sate: November 7, 2022 
Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean early - November. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate La Niña is favored to continue through during the Northern Hemisphere winter (December-February) 2022-23, with a 54% chance for ENSO-neutral in February-April 2023.

Indian Sea Sate
Sea surface temperature around Sri Lanka was above 0.5℃ to the whole country in 26th October, 2022. Across the Indian Ocean, a classical negative Indian Ocean Dipole prevails as is typical during a La Niña.

 

Interpretation


Monitoring
Rainfall: 
During the last two weeks, there had been heavy rainfall over the following areas: Kegalle, Mullaitivu, Galle and Rathnapura
Daily Average Rainfall in the Met stations for previous week of (1st November – 8th November) =
16.8 mm
Rmax: 116.0 mm & Rmin: 0.0 mm.

Region

Average rainfall for the Last 8 days

Northern Plains

15.5 mm

Eastern

20.0 mm

Western

14.6 mm

Southern Plains

19.8 mm


The Hydro Catchment Areas recorded 15.3 mm of average rainfall for the last week
Rmax: 74.5 mm & Rmin: 0.0 mm. 

Wind:
North-westerly and North-easterly winds prevailed in the sea area and around the island last week. 
Temperature: 
The temperature anomalies were below normal for some parts of the Northern province, and above normal for some parts of the Southern province, driven by the warm SST’s.

Predictions
Rainfall:
During the next week (9th – 15th November), above 135 mm rainfall is predicted for the Western, Northern, Southern and Sabaragamuwa provinces; and heavy (≥ 125 mm) rainfall is expected for the rest of the country.
Temperature:
The temperature will remain below normal for some parts of the Central and Uva provinces during 10th – 16th November.
Teleconnections:
La Niña is favored to continue through during the Northern Hemisphere winter (December-February) 2022-23, with a 54% chance for ENSO-neutral in February-April 2023.
MJO shall near neutral the rainfall during 9th– 23rd November for Sri Lanka.

Seasonal Precipitation: 
The precipitation forecast for the November-December-January 2023 season shows a higher tendency for above-normal precipitation in the north half of the country.