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Friday, September 23, 2022

Climate Bulletin For Sri Lanka (23 September 2022)

  


Highlights          


 • During the next week (23rd- 27th September) moderate rainfall is predicted for the Sabaragamuwa and Western  province, and less rainfall is expected for the rest of the country.
 • During the last week, the average daily rainfall over Sri Lanka was 0.4 mm and hydro catchment areas received 0.1 mm on average.
 • From 12th- 18th September, up to 8m/s of  south-westerly  were experienced at 850 mb level over the island. south-westerly winds are expected next week.
 • Sea surface temperature around Sri Lanka was above 0.5℃ to the North of the country. Land surface temperature remained near normal.



Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 21st September – 27th September:
Total rainfall by Provinces:  
  •     35 mm - Sabaragamuwa, Western
  • < 25 mm - North Central, Central, North Western, Southern
From 28th September – 4th October:
Total rainfall by Provinces:
  •    55 mm - Sabaragamuwa, Western
  •    45 mm - North Western, Southern
  •    35 mm - Central
  •    25 mm - Eastern
  • < 15 mm - Uva, North Central, Northern
MJO based OLR predictions:
For the next 15 days: 
MJO shall near neutral during 21st September – 25th September and start to slightly enhance rainfall during 26th September onwards for Sri Lanka.

Ocean State (Text Courtesy IRI)
Pacific Sea Sate: September 14, 2022 
Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean early-September. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate, La Niña is favored to continue through Northern Hemisphere winter 2022-23, with a 91% chance in September-November, decreasing to a 54% chance in January-March 2023.

Indian Sea Sate
Sea surface temperature around Sri Lanka was above 0.5 to the North of the country. 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 light to moderate rainfall over the following area: Galle
Daily Average Rainfall in the Met stations for previous week of (13th Sep - 20th Sep) = 0.4 mm
Rmax: 19.4 mm & Rmin: 0.0 mm.

Region

Average rainfall for the Last 8 days

Northern Plains

0.0 mm

Eastern

0.5 mm

Western

0.6 mm

Southern Plains

0.0 mm


The Hydro Catchment Areas recorded 0.1 mm of average rainfall for the last week
Rmax: 3.7 mm & Rmin: 0.0 mm. 
Wind:
South-westerly winds prevailed in the sea area and around the island last week. 
Temperature: 
The temperature anomalies were below for the northern province, driven by the warm SST’s.

Predictions
Rainfall:
During the next week (23rd- 27th September) moderate rainfall is predicted for the Sabaragamuwa and Western provinces, and less rainfall is expected for the rest of the country.
Temperature:
The temperature will remain above normal for the Northern, North central, Uva, and Eastern provinces during 23rd September – 29th September.
Teleconnections:
La Niña is favored to continue through Northern Hemisphere winter 2022-23, with a 91% chance in September-November, decreasing to a 54% chance in January-March 2023.
MJO shall near neutral during 21st September – 25th September and start to heavily enhance rainfall during 26th September onwards for Sri Lanka.

Seasonal Precipitation: 
The precipitation forecast for the October-November-December 2022 season shows a higher tendency for below-normal precipitation to the southern half of the country. 

Friday, September 16, 2022

Climate Bulletin For Sri Lanka (16 September 2022)

 


Highlights          


 • During the next week (16th- 20th September) moderate rainfall is predicted for the Western and Sabaragamuwa provinces, and less rainfall is expected for rest of the country.
 • During the last week, the average daily rainfall over Sri Lanka was 0.5 mm and hydro catchment areas received 1.6 mm on average.
 • From 5th- 11th September, up to 15m/s of  south-westerlies were experienced at 850 mb level over the island. South-westerly winds are expected next week.
 • Sea surface temperature around Sri Lanka was around 25 - 30℃ to the North and West of the country. Land surface temperature remained near normal.



Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 14th September – 20th September:
Total rainfall by Provinces: 
  •   35 mm - Western, Sabaragamuwa
  • < 25 mm - North Western, Central, Southern 
From 21st September – 27th September:
Total rainfall by Provinces:
  •   45 mm - Western, Sabaragamuwa
  •   35 mm - Central
  •   25 mm - North Western, Southern
  • < 15 mm - Uva, Eastern, North Central, Northern
MJO based OLR predictions:
For the next 15 days: 
MJO shall near neutral for Sri Lanka during 14th September – 28th September.

Ocean State (Text Courtesy IRI)
Pacific Sea Sate: September 8, 2022 
Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean early-September. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate, La Niña is favored to continue through Northern Hemisphere winter 2022-23, with a 91% chance in September-November, decreasing to a 54% chance in January-March 2023.

Indian Sea Sate
Sea surface temperature around Sri Lanka was around 25 - 30 to the North and West of the country. 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 fairly heavy rainfall over the following area: Colombo
Daily Average Rainfall in the Met stations for previous week of (6th Sep - 13th Sep) = 0.5 mm
Rmax: 16.2 mm & Rmin: 0.0 mm.

Region

Average rainfall for the Last 8 days

Northern Plains

0.0 mm

Eastern

0.0 mm

Western

1.4 mm

Southern Plains

0.1 mm


The Hydro Catchment Areas recorded 1.6 mm of average rainfall for the last week
Rmax: 36.9 mm & Rmin: 0.0 mm. 
Wind:
South-westerly winds prevailed in the sea area and around the island last week. 
Temperature: 
The temperature anomalies were below for the northern half of the island and were even lower in provinces like Uva and Sabaragamuwa, driven by the warm SST’s.
Predictions
Rainfall:
During the next week (16th- 20th September) moderate rainfall is predicted for the Western and Sabaragamuwa provinces, and less rainfall is expected for the rest of the country.
Temperature:
The temperature will remain above normal for the Northern, North central, Uva and Eastern provinces during 16th September – 22nd September.
Teleconnections:
La Niña is favored to continue through Northern Hemisphere winter 2022-23, with a 91% chance in September-November, decreasing to a 54% chance in January-March 2023.
MJO shall near neutral for Sri Lanka during 14th September – 28th September.

Seasonal Precipitation: 
The precipitation forecast for the October-November-December 2022 season shows a higher tendency for below-normal precipitation to the southern half of the country. 

Friday, September 9, 2022

Climate Bulletin For Sri Lanka (9 September 2022)


Highlights          


 • Moderate rainfall is predicted for the Western province, and less rainfall is expected for the rest of the country during 9th-13th September.
 • During the last week, the average daily rainfall over Sri Lanka was 12.7 mm and hydro catchment areas received 80.9 mm on average.
 • From 29th August- 4th September, up to 10m/s of  South-westerlies were experienced at 850 mb level over the island. South-westerly winds are expected next week.
 •  Sea surface temperature around Sri Lanka was above 0.5℃ to the North of Sri Lanka. Land surface temperature remained near normal.



Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 7th September – 13th September:
Total rainfall by Provinces: 
  •    35 mm - Western, Sabaragamuwa
  • < 15 mm - North Western, Central, Southern
From 14th September – 20th September:
Total rainfall by Provinces: 
  •    35 mm - Central, Sabaragamuwa
  •    25 mm - Western, Uva
  • < 15 mm - Southern, Eastern
MJO based OLR predictions:
For the next 15 days: 
MJO shall near neutral during 7th September – 16th September and slightly suppress rainfall during 17th September – 21st September.


Ocean State (Text Courtesy IRI)
Pacific Sea Sate: September 5, 2022 
Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean in Early-September. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate, La Niña is expected to continue, with chances for La Niña gradually decreasing from 86% in the coming season to 60% during December-February 2022-23.

Indian Sea Sate
Sea surface temperature around Sri Lanka was above 0.5 to the North of Sri Lanka. 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 area: Ratnapura
Daily Average Rainfall in the Met stations for previous week of (30th Aug - 6th Sep) = 12.7 mm
Rmax: 247.1 mm & Rmin: 0.0 mm.

Region

Average rainfall for the Last 8 days

Northern Plains

5.0 mm

Eastern

9.2 mm

Western

25.7 mm

Southern Plains

1.7 mm


The Hydro Catchment Areas recorded 80.9 mm of average rainfall for the last week
Rmax: 207.4 mm & Rmin: 0.0 mm.
Wind:
South- westerly winds prevailed in the sea area and around the island last week. 
Temperature: 
The temperature anomalies were below for the northern half of the island and were even lower in the North Central region of the island, driven by the warm SST’s.
Predictions
Rainfall:
During the next week (9th- 13th September) moderate rainfall is predicted for the Western province, and less rainfall is expected for the rest of the country.
Temperature:
The temperature will remain slightly above normal for the Northern, North Central, Uva and Eastern provinces during 8th September – 14th September.
Teleconnections:
La Niña is expected to continue, with chances for La Niña gradually decreasing from 86% in the coming season to 60% during December-February 2022-23.
MJO shall near neutral during 7th September – 16th September and slightly suppress rainfall during 17th September – 21st September.

Seasonal Precipitation: 
The precipitation forecast for the September-October-November season shows a higher tendency for below-normal precipitation for the country. 

Friday, September 2, 2022

Climate Bulletin For Sri Lanka (2 September 2022)

  

Highlights          


 • Up to 80 mm of rainfall is predicted for Central and Sabaragamuwa provinces, below 75mm of rainfall is expected for the rest of the country  during 2nd-7th September.
 • During the last week, the average daily rainfall over Sri Lanka was 5.6 mm and hydro catchment areas have received 10.13 mm on average.
 • From 22nd- 28th August, south-westerly  of 10m/s winds were experienced at 850 mb level over the island. Upto 10m/s of westerlies to south-westerly winds expected for the next week.
 •  Sea surface temperature around Sri Lanka was above 0.5℃ to the north of Sri Lanka. Land surface temperature remained near normal.



Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 31st August – 6th September:
Total rainfall by Provinces: 
  • 85 mm - Sabaragamuwa, Central
  • 75 mm - Southern, Western
  • 65 mm - Uva, Eastern, North Central
  • 55 mm - Northern, North Western
From 7th September – 13th September:
Total rainfall by Provinces: 
  •   35 mm - Central, Sabaragamuwa
  •   25 mm - Western, Uva
  • < 15 mm - Southern, Eastern
MJO based OLR predictions:
For the next 15 days: 
MJO shall slightly enhance the rainfall during 31st August - 4th September and shall near neutral during 5th September – 14th September.


Ocean State (Text Courtesy IRI)
Pacific Sea Sate: August 24, 2022 
Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean in late-August. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate, La Niña is expected to continue, with chances for La Niña gradually decreasing from 86% in the coming season to 60% during December-February 2022-23.

Indian Sea Sate
Sea surface temperature around Sri Lanka was above 0.5 to the north of Sri Lanka. 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 area: Polonnaruwa
Daily Average Rainfall in the Met stations for previous week of (22nd Aug - 29th Aug) = 5.6 mm
Rmax: 102.5 mm & Rmin: 0.0 mm.

Region

Average rainfall for the Last 8 days

Northern Plains

5.7 mm

Eastern

7.0 mm

Western

5.4 mm

Southern Plains

0.0 mm


The Hydro Catchment Areas recorded 10.13 mm of average rainfall for the last week
Rmax: 96.5 mm & Rmin: 0.0 mm. 
Wind:
South-westerly winds prevailed in the sea area and around the island last week. 
Temperature: 
The temperature anomalies were below normal for the northern half of the island, driven by the warm SST’s.
Predictions
Rainfall:
During the next week (2nd- 6th September) up to 80 mm of rainfall is predicted for Central and Sabaragamuwa provinces, and < 75mm rainfall is expected for the rest of the country.
Temperature:
The temperature will remain slightly above normal for the Uva province during 2nd September – 7st September.
Teleconnections:
La Niña - La Niña is expected to continue, with chances for La Niña gradually decreasing from 86% in the coming season to 60% during December-February 2022-23.
MJO shall slightly enhance the rainfall during 31st August - 4th September and shall near neutral during 5th September – 14th September.

Seasonal Precipitation: 
The precipitation forecast for the September-October-November season shows a higher tendency for below-normal precipitation for the country.