Climate Bulletin For Sri Lanka (4 August 2023)

  

Highlights          

 • Moderately rainfall (25 mm) is predicted for the Sabaragamuwa provinces and less rainfall is predicted for the rest of the country during 3 - 9 Aug. Fairly heavy rainfall (55mm) is predicted for the Southern and Sabaragamuwa provinces during 10 - 16 Aug.

 • During the last week, average daily rainfall over Sri Lanka was 0.1 mm and  hydro catchment areas received 0.2 mm.

 • From 25 - 31 Jul, up to 15 m/s of north westerly winds were at 850 mb (1.5 km). During 4 - 10 Aug, up to 10 m/s of northwest-westerly winds are expected at 850 mb (1.5 km). 

 • Sea surface temperature around Sri Lanka was 0.25 - 1.5ºC above normal. Average maximum land temperature ranged from 31 - 33ºC and minimum ranged from 24 - 25ºC with a drop in the hills. 

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Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 3^rd August – 9^th August:  

Total rainfall by Provinces

• 25 - Sabaragamuwa
• 15 - Southern, Western, Central
• ≤ 5 - Northern, North Western, North Central, Eastern, Uva

From 10^th August – 16^th August:  

Total rainfall by Provinces

• 55 - Southern, Sabaragamuwa
• 45 - Western, Central, Uva
• 25 - Eastern, North Western
• ≤ 15  - Northern, North Central

MJO based OLR predictions:

For the next 15 days: 

MJO shall near neutral the rainfall during 3^rd - 17^th August for Sri Lanka.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: July 31, 2023 

El Nino Mode has set in now according to NOAA since 8^th of June. Equatorial sea surface temperatures (SSTs) are above average across the central and eastern Pacific Ocean late-July. There is a greater than 90% chance that El Niño conditions will continue through the Northern Hemisphere winter.

Indian Sea Sate

Sea surface temperature around Sri Lanka was near normal to the country in 11^th - 17^th July, 2023. A positive Dipole Mode has set in across the Indian Ocean since 8^th of June.

 

Interpretation

Monitoring

Rainfall:

During the last two weeks, there had been light showers over the following areas: Bandarawela, Galle
Daily Average Rainfall in the Met stations for previous week of (26^th July - 2^nd August) = 0.1 mm 
Maximum Daily Rainfall: 14.3 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	0.0	34.2	26.3
Eastern hills	1.0	30.3	19.1
Eastern plains	0.1	35.7	25.5
Western hills	0.0	27.7	20.6
Western plains	0.1	30.8	26.8
Southern plains	0.0	34.6	25.8

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	0.2	4.0	0.0

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

Predictions

Rainfall: During the next week (3^rd August - 9^th August), moderately rainfall (25 mm) is predicted for the Sabaragamuwa province 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 4^th August - 10^th August.

Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8^th of June. MJO shall near neutral the rainfall during 3^rd - 17^th August for Sri Lanka.

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