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Friday, May 26, 2023

Climate Bulletin For Sri Lanka (26 May 2023)

      


Highlights          


 • Fairly heavy rainfall is predicted for the  Sabaragamuwa, Western, Southern, North Western, Central provinces during 25 - 31 May. Heavy rainfall is predicted for the Western, Sabaragamuwa, Southern, North Western provinces during 1 - 7 June.
 • During the last week, average daily rainfall over Sri Lanka was 2.7 mm and  hydro catchment areas received 2.6 mm.
 • From 16 - 22 May, up to 5 m/s of south westerly winds were at 850 mb (1.5 km). During 26 May - 1 June, up to 10 m/s of westerly winds are expected at 850 mb (1.5 km). 
 • Sea surface temperature around Sri Lanka was 0.5 - 1.5ºC above normal. Average maximum land temperature ranged from 32- 33ºC and average minimum ranged from 23 - 25ºC with a drop in the hills. 



Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 25th May – 31st May:
Total rainfall by Provinces:    
  • 85 - Western, Sabaragamuwa
  • 75 - Southern
  • 65 - North Western
  • 55 - Central
  • 35 - Northern, North Central, Uva
  • ≤ 25 - Eastern
From 1st June – 7th June:
Total rainfall by Provinces:   
  • 125 - Western, Sabaragamuwa
  • 115 - Southern
  • 105 - North Western
  • 95  - Central
  • 75  - Uva
  • 65  - North Western, Northern
  • 55  - Eastern
MJO based OLR predictions:
For the next 15 days: 
MJO shall significantly suppress the rainfall during 24th – 28th May, slightly suppress the rainfall during 29th May – 2nd June, and slightly increase the rainfall during 3rd – 7th June for Sri Lanka.


Ocean State (Text Courtesy IRI)
Pacific Sea Sate: May 22, 2023 
Equatorial sea surface temperatures (SSTs) are near-to-above average across most of the Pacific Ocean mid-May. The tropical Pacific atmosphere is consistent with ENSO-neutral conditions. A large majority of the models indicate a transition from ENSO-neutral conditions in the next couple of months, with a greater than 90% chance of El Niño persisting into the Northern Hemisphere winter.

Indian Sea Sate
Sea surface temperature around Sri Lanka was 0.5º C above normal to the Eastern and Western half of the country in 2nd – 8th May, 2023. 

 

Interpretation


Monitoring

Rainfall:

During the last two weeks, there had been heavy rainfall over the following area:  Galle

Daily Average Rainfall in the Met stations for previous week of (17th May – 24th May) = 2.7 mm

Maximum Daily Rainfall: 46.6 mm & Minimum Daily Rainfall: 0.0 mm. 


Region

Average rainfall for the Last 8 days

Northern Plains

0.5 mm

Eastern

1.1 mm

Western

6.5 mm

Southern Plains

1.9 mm


The Hydro Catchment Areas recorded 2.6 mm of average rainfall for the last week.

Maximum Daily Rainfall: 46.3 mm & Minimum Daily Rainfall: 0.0 mm.

Wind: South Westerly winds prevailed in the sea area and around the island last week.

Temperature: The temperature anomalies were above normal for some parts of the Western, Sabaragamuwa, Central, and North Western provinces and normal for rest of the country driven by the warm SST’s.


Predictions
Rainfall:
During the next week (25th May – 31st May), fairly heavy rainfall (≥ 55 mm) is predicted for the Western, Sabaragamuwa, Southern, North Western, and Central provinces and less rainfall is predicted for rest of the country
Temperature:
The temperature will remain above normal for some parts of the Northern, Eastern, North Central, Uva, and Southern provinces during 26th May – 1st June.
Teleconnections:
A transition from ENSO-neutral conditions in the next couple of months, with a greater than 90% chance of El Niño persisting into the Northern Hemisphere winter.
MJO shall significantly suppress the rainfall during 24th – 28th May, slightly suppress the rainfall during 29th May – 2nd June, and slightly increase the rainfall during 3rd – 7th June for Sri Lanka.

Seasonal Precipitation: 
The precipitation forecast for the June-July-August, 2023 season shows above normal precipitation for the country.

Saturday, May 20, 2023

Climate Bulletin For Sri Lanka (19 May 2023)

     


Highlights          


 • Fairly heavy rainfall is predicted for the  Western and Sabaragamuwa provinces and less rainfall is predicted for rest of the country durring 18th May – 24th May.
 • During the last week, average daily rainfall over Sri Lanka was 1.7 mm and  hydro catchment areas received 8.8 mm. Rainfall reached 50mm in the south-west shadow of the central mountains. Cyclone Mocha made landfall in Myanmar with extreme rain. 
 • From 9thMay - 15th May, up to 8 m/s of westerly winds were at 850 mb level. During 20th- 26th May, up to 8 m/s of Easterly winds are expected at 850 mb. Cyclone Mocha long range impact led to strong South-westerly wind over SL.
 • Sea surface temperature around Sri Lanka was about 0.5 - 1 degree above the seasonal norm. Land surface temperature remained near normal.



Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 18th May – 24th May:
Total rainfall by Provinces:    
  • 75mm - Western
  • 55 mm - Sabaragamuwa
  • 45 mm - Southern, North Western
  • 25 mm - Central
  • 15 mm - Uva
  • 25 mm - Northern, North Central, Eastern
From 25th May – 31st May:
Total rainfall by Provinces:   
  • 85 mm - Western
  • 45 mm - Sabaragamuwa, Southern, North Western
  • 35 mm - Central, Uva
  • 25 mm - Northern, North Central, Eastern
MJO based OLR predictions:
For the next 15 days: 
MJO shall moderately suppress the rainfall during 17th May – 2nd June for Sri Lanka.


Ocean State (Text Courtesy IRI)
Pacific Sea Sate: May 15, 2023 
Equatorial sea surface temperatures (SSTs) are near-to-above average across most of the Pacific Ocean mid-May. The tropical Pacific atmosphere is consistent with ENSO-neutral conditions. A large majority of the models indicate ENSO-neutral conditions are expected to continue through the Northern Hemisphere spring, followed by a 90% chance of El Nino developing during May-July 2023

Indian Sea Sate
Sea surface temperature around Sri Lanka was 0.5ºC above normal to the country except northern half in 25th April– 1st May, 2023

 

Interpretation


Monitoring

Rainfall:

During the last two weeks, there had been heavy rainfall over the following area:  Rathnapura.

Daily Average Rainfall in the Met stations for previous week of (11th May – 17th May) = 1.7 mm

Maximum Daily Rainfall: 48 mm & Minimum Daily Rainfall: 0.0 mm. 


Region

Average rainfall for the Last 8 days

Northern Plains

0.3 mm

Eastern

0.7 mm

Western

4.4 mm

Southern Plains

0.1 mm


The Hydro Catchment Areas recorded 8.0 mm of average rainfall for the last week.

Maximum Daily Rainfall: 78.0 mm & Minimum Daily Rainfall: 0.0 mm.

Wind: Westerly 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, North Central, and Eastern provinces and normal for rest of the country driven by the warm SST’s.


Predictions
Rainfall:
During the next week (18th May – 24th May), fairly heavy rainfall (≥ 55 mm) is predicted for the Western and Sabaragamuwa provinces and less rainfall is predicted for rest of the country.
Temperature:
The temperature will remain above normal for some parts of the Northern, Eastern, North Central, Southern, and Uva provinces during 20th May – 26th May.
Teleconnections:
ENSO-neutral conditions are expected to continue through the Northern Hemisphere spring, followed by a 90% chance of El Nino developing during May-July 2023.
MJO shall moderately suppress the rainfall during 17th May – 2nd June for Sri Lanka.

Seasonal Precipitation: 
The precipitation forecast for the June-July-August, 2023 season shows above normal precipitation for the country.

Friday, May 12, 2023

Climate Bulletin For Sri Lanka (12 May 2023)

     


Highlights          


 • Fairly heavy rainfall is predicted for the Sabaragamuwa, Western, Southern, North Western, and Central provinces. Cyclone Mocha can lead to high winds and rainfall in South-west facing mountain slopes during 12th- 15th May.
 • During the last week, average daily rainfall over Sri Lanka was 13.2 mm and  hydro catchment areas received 8.9 mm. The western slopes, hills and eastern hills received above-normal rainfall.
 • From 2nd- 8th May, up to 8 m/s of North westerly winds were at 850 mb level. During 12th- 18th May, up to 8 m/s of Easterly winds are expected at 850 mb. Long-range impact of Cyclone Mocha in Central BoB(engal) will lead to high wind 
 • Sea surface temperature around Sri Lanka was about 0.5 - 1 degree above the seasonal norm. Land surface temperature remained near normal.



Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 11th May – 17th May:
Total rainfall by Provinces:    
  • 95 mm - Western
  • 85 mm - Sabaragamuwa
  • 75 mm - Southern, North Western
  • 65 mm - Central
  • 45 mm - Uva
  • 35 mm - Northern, North Central, Eastern
From 18th May – 24th May:
Total rainfall by Provinces:   
  • 115 mm - Western
  •  95 mm - Sabaragamuwa, Southern, North Western
  •  75 mm - Central, Uva
  •  55 mm - Northern, North Central, Eastern
MJO based OLR predictions:
For the next 15 days: 
MJO shall slightly suppress the rainfall during 11th May – 25th May for Sri Lanka.


Ocean State (Text Courtesy IRI)
Pacific Sea Sate: May 8, 2023 
Equatorial sea surface temperatures (SSTs) are near-to-above average across most of the Pacific Ocean early-May. The tropical Pacific atmosphere is consistent with ENSO-neutral conditions. A large majority of the models indicate ENSO-neutral conditions are expected to continue through the Northern Hemisphere spring, followed by a 62% chance of El Nino developing during May-July 2023.

Indian Sea Sate
Sea surface temperature around Sri Lanka was 0.5ºC above normal to the country except northern half in 18th – 24th April, 2023. 

 

Interpretation


Monitoring

Rainfall:

During the last two weeks, there had been heavy rainfall over the following area:  Katunayake

Daily Average Rainfall in the Met stations for previous week of (3rd May – 10th May) = 13.2 mm

Maximum Daily Rainfall: 171.1 mm & Minimum Daily Rainfall: 0.0 mm. 


Region

Average rainfall for the Last 8 days

Northern Plains

15.3 mm

Eastern

10.7 mm

Western

17.3 mm

Southern Plains

6.6 mm


The Hydro Catchment Areas recorded 8.9 mm of average rainfall for the last week.

Maximum Daily Rainfall: 61.0 mm & Minimum Daily Rainfall: 0.0 mm.

Wind: North westerly winds prevailed in the sea area and around the island last week.

Temperature: The temperature anomalies were below normal for Northern, North Central, and North Western provinces and some parts of the Eastern, and Central provinces driven by the warm SST’s.


Predictions
Rainfall:
During the next week (11th May – 17th May), fairly heavy rainfall (≥ 65 mm) is predicted for the Western, Sabaragamuwa, Southern, North Western, and Central provinces and less rainfall is predicted for rest of the country.
Temperature:
The temperature will remain above normal for some parts of the Northern, Eastern, North Central, Southern, and Uva provinces during 12th May – 18th May.
Teleconnections:
ENSO-neutral conditions are expected to continue through the Northern Hemisphere spring, followed by a 62% chance of El Nino developing during May-July 2023.
MJO shall slightly suppress the rainfall during 11th May – 25th May for Sri Lanka.

Seasonal Precipitation: 
The precipitation forecast for the May-June-July, 2023 season shows near normal precipitation for the country.