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Friday, August 25, 2023

Climate Bulletin For Sri Lanka (25 August 2023)

     

Highlights          


 • Light showers (25 mm) are predicted for the Sabaragamuwa, Southern, Northern, Uva provinces during 24 - 30 Aug. Fairly heavy rainfall (≥ 55mm) is predicted for the Sabaragamuwa, Southern, Western, Uva, Central, North Western provinces during 31 Aug - 6 Sep. 
 • During the last week, average daily rainfall over Sri Lanka was 'light' (0.9 mm) and  hydro catchment areas received  'light' (1.2 mm) showers.
 • From 15 - 21 Aug, up to 10 m/s of northwest-westerly winds were at 850 mb (1.5 km). During 25 - 31 Aug, up to 10 m/s of northwest-southwesterly winds are expected at 850 mb (1.5 km). 
 • Sea surface temperature around Sri Lanka was 0.5 - 2ºC above normal. From 16 - 23 Aug, maximum daily temperature was recorded in Vavuniya (38.5ºC), Polonnaruwa (38.1ºC) and Pottuvil (37.5ºC).




Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 24th August – 30th August:   
Total rainfall by Provinces
  • 25mm - Southern, Sabaragamuwa, Northern, Uva
  • ≤ 15mm - Central, Eastern, Western, North Central, North Western
From 31st August – 6th September:   
Total rainfall by Provinces
  • 85mm - Southern
  • 75mm - Sabaragamuwa, Western
  • 65mm - Uva, Central
  • 55mm - North Western
  • 45mm - Eastern
  •  ≤ 35mm - North Central, Northern
MJO based OLR predictions:
For the next 15 days: 
MJO shall near neutral the rainfall during 23rd August - 1st September and slightly enhance the rainfall during 2nd - 6th September for Sri Lanka.


Ocean State (Text Courtesy IRI)
Pacific Sea Sate: August 21, 2023 
El Nino Mode has set in according to NOAA since 8th of June. Equatorial sea surface temperatures (SSTs) are above average across the central and eastern Pacific Ocean mid-August. El Niño conditions will continue through the Northern Hemisphere winter (with greater than a 95% chance through December 2023-February 2024).

Indian Sea Sate
Sea surface temperature around Sri Lanka was 0.5 above normal to the country in 1st - 7th August, 2023. A positive Dipole Mode has set in across the Indian Ocean since 8th of June.

 

Interpretation


Monitoring
Rainfall:

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


Daily Average Rainfall in the Met stations for previous week of (16th August - 23rd August) = 0.9 mm

Maximum Daily Rainfall: 29.8 mm & Minimum Daily Rainfall: 0.0 mm. 


Region

Average rainfall for last 8 days (mm)

Average temperature for last 8 days (ºC)

Maximum

Minimum

Northern plains

0.4

34.4

26.2

Eastern hills

0.2

30.2

18.2

Eastern plains

1.1

35.8

25.1

Western hills

1.0

29.2

20.0

Western plains

1.6

32.2

26.7

Southern plains

0.8

33.5

25.3











Region

Average rainfall for last 8 days (mm)

Daily maximum rainfall for last 8 days (mm)

Daily minimum rainfall for last 8 days (mm)

Hydro catchment

1.2

46.2

0.0







Wind: Northwest-westerly winds prevailed in the sea area and around the island last week.
Temperatures: The temperature anomalies were above normal for the Western, Sabaragamuwa provinces and some parts of the Southern, Central, Uva, and North Western provinces of the country driven by the warm SST’s.


Predictions
Rainfall: During the next week (24th August - 30th August), light showers (25 mm) are predicted for the Southern, Sabaragamuwa, Northern, and Uva provinces and less rainfall is predicted for the rest of the country.
Temperatures: The temperature will remain above normal for some parts of the Eastern, Uva, Northern, North Central, Southern, and Central provinces during 25th August - 31st August.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June.
MJO shall near neutral the rainfall during 23rd August - 1st September and slightly enhance the rainfall during 2nd - 6th September for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the September-October-November, 2023 season shows above normal precipitation for the country.

Friday, August 18, 2023

Climate Bulletin For Sri Lanka (18 August 2023)

    

Highlights          


 • Light showers are predicted for the Sabaragamuwa, Southern, Uva, Western, Central and Northern provinces during 17 - 23 Aug.
 • During the last week, average daily rainfall over Sri Lanka was 'light' (2.0 mm) and  hydro catchment areas received  'light' (2.0 mm) showers.
 • From 8 - 14 Aug, up to 8 m/s of northwest-westerly winds were at 850 mb (1.5 km). During 18 - 24 Aug, up to 10 m/s of northwest-southwesterly winds are expected at 850 mb (1.5 km). 
 • Sea surface temperature around Sri Lanka was 1 - 1.5ºC above normal. From 9 - 16 Aug, maximum daily temperature was recorded in Polonnaruwa (38.1ºC), Anuradhapura (37.8ºC) and Vavuniya (37.7ºC).




Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 17th August – 23rd August:   
Total rainfall by Provinces
  • 15 - Southern, Sabaragamuwa, Uva, Western, Central, Northern 
  • ≤ 5 - North Western, Eastern, North Central
MJO based OLR predictions:
For the next 15 days: 
MJO shall slightly suppress the rainfall during 17th - 21st August and near neutral the rainfall during 22nd - 31st August for Sri Lanka.


Ocean State (Text Courtesy IRI)
Pacific Sea Sate: August 14, 2023 
El Niño Mode has set in according to NOAA since 8th of June. Equatorial sea surface temperatures (SSTs) are above average across the central and eastern Pacific Ocean mid-August. El Niño conditions will continue through the Northern Hemisphere winter (with greater than a 95% chance through December 2023-February 2024).

Indian Sea Sate
Sea surface temperature around Sri Lanka was 0.5 above normal to the Western and Northern half of the country in 18th - 24th July, 2023. A positive Dipole Mode has set in across the Indian Ocean since 8th of June.

 

Interpretation


Monitoring
Rainfall:

During the last two weeks, there had been fairly heavy rainfall over the following areas: Monaragala, Mullaittivu, Kandy

            

Daily Average Rainfall in the Met stations for previous week of (9th August - 16th August) = 2.0 mm

Maximum Daily Rainfall: 63.7 mm & Minimum Daily Rainfall: 0.0 mm. 


Region

Average rainfall for last 8 days (mm)

Average temperature for last 8 days (ºC)

Maximum

Minimum

Northern plains

1.7

34.1

25.9

Eastern hills

5.1

29.2

17.6

Eastern plains

1.9

35.4

24.9

Western hills

1.3

29.2

19.1

Western plains

1.7

31.8

26.4

Southern plains

0.0

33.6

25.4












Region

Average rainfall for last 8 days (mm)

Daily maximum rainfall for last 8 days (mm)

Daily minimum rainfall for last 8 days (mm)

Hydro catchment

2.0

48.0

0.0







Wind: Northwest-westerly winds prevailed in the sea area and around the island last week.
Temperatures: The temperature anomalies were above normal for the Sabaragamuwa, Central, North Central, Western, and North Western provinces and some parts of the Southern, Eastern, Uva, and Northern provinces of the country driven by the warm SST’s.


Predictions
Rainfall: During the next week (17th August - 23rd August), light showers (15 mm) are predicted for the Southern, Sabaragamuwa, Uva, Western, Central, and Northern provinces and less rainfall is predicted for the rest of the country.
Temperatures: The temperature will remain above normal for some parts of the Eastern, Uva, Northern, North Central, Southern, and Central provinces during 18th August - 24th August.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June.
MJO shall slightly suppress the rainfall during 17th - 21st August and near neutral the rainfall during 22nd - 31st August for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the September-October-November, 2023 season shows above normal precipitation for the country.