Climate Bulletin For Sri Lanka (28 July 2023)

 

Highlights          

 • Moderately rainfall (35 mm) is predicted for the Southern, Sabaragamuwa provinces and less rainfall is predicted for the rest of the country during 27 Jul - 2 Aug.

 • During the last week, average daily rainfall over Sri Lanka was 1.7 mm and  hydro catchment areas received 4.5 mm. Highest average rainfall of 5.4 mm/day received in Western plains

 • From 18 - 24 Jul, up to 20 m/s of north westerly winds were at 850 mb (1.5 km). During 28 Jul - 3 Aug, up to 15 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 27^th July – 2^nd August:  

Total rainfall by Provinces

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

MJO based OLR predictions:

For the next 15 days: 

MJO shall near neutral the rainfall during 27^th July - 10^th August for Sri Lanka

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: July 24, 2023 

El Nino Mode has set in now according to NOAA since 8th 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 4^th - 10^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 fairly heavy rainfall over the following area: Nuwara Eliya
Daily Average Rainfall in the Met stations for previous week of (19^th July – 26^th July) = 1.7 mm
Maximum Daily Rainfall: 52.4 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	0.2	33.2	26.5
Eastern hills	0.0	29.0	19.6
Eastern plains	0.0	35.7	25.6
Western hills	4.5	26.1	20.9
Western plains	5.4	30.8	26.1
Southern plains	0.4	34.6	25.6

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	4.5	32.6	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 Sabaragamuwa, Southern, Western, Uva, Central, Eastern, and Northern provinces of the country driven by the warm SST’s.

Predictions

Rainfall: During the next week (27^th July – 2^nd August), moderately rainfall (35 mm) is predicted for the Southern and Sabaragamuwa 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, and Southern provinces and below normal for some parts of the Central province during 28^th July – 3^rd 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 27^th July - 10^th August for Sri Lanka.

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