Highlights
• During 15 - 21 Aug, high likelihood of heavy rainfall (100 - 150 mm) is predicted for the Sabaragamuwa, Western, Uva, Central and Southern provinces fairly heavy rainfall (50 - 100 mm) is predicted for the North Central, North Western and Eastern provinces; moderate rainfall (25-50 mm) is predicted for the Northen province. High likelihood of heavy rainfall (100 - 150 mm) is predicted for the Southwest corner of SL during 15-21 Aug.
• On average, 6.6 mm was received in SL and rainfall was concentrated in the Western hills (9.6 mm) and Northern (7.7 mm) and Eastern (7 mm) plains for last 8 days. On average, 7.5 mm was received in the hydro catchments in SL; Neboda (Kalutara District) received the highest rainfall (65 mm) for last 8 days. Highest daily rainfall was in Mahailluppallama on 11 Aug (96.4 mm).
• From 7 Aug - 13 Aug, winds at 850mb (1.5km) were north- westerly, reaching up to 15 m/s. From 16 Aug - 22 Aug, winds are predicted to be westerly and north-westerly, reaching up to 15 m/s.
• Average land surface temperature was 31.0ºC in the last week with warmer anomalies from seasonal average of 1-3 ºC. Northern plains was warmest followed by Eastern, Western and Southern plains. Sea surface temperature around Sri Lanka was normal to the North Eastern and some parts of the Northern side of the country and 1.5℃ above average for the other half of the country.
Predictions
Rainfall
14-day prediction:NOAA NCEP models:
From 15th August - 21st August:
Total rainfall by Provinces
- 135≤ mm - Southern
- 125 mm - Sabaragamuwa, Western
- 105 mm - Uva, Central
- 85 mm - North Western
- 75 mm - North Central, Eastern
- ≤45 mm - Northern
From 22nd August - 28th August:
Total rainfall by Provinces
- 55 mm - Southern
- 45 mm - Western, Sabaragamuwa, Central
- ≤25 mm - Uva, North Western, North Central, Eastern, Northern
MJO based OLR predictions:
For the next 15 days:
MJO shall slightly enhance the rainfall during 15th – 24th August and near neutral the rainfall during 25th August – 29th August for Sri Lanka.
Ocean State (Text Courtesy IRI)
Pacific Sea Sate: August 12, 2024
ENSO-neutral conditions are present. Equatorial sea surface temperatures (SSTs) are above average in the western Pacific, near average in the east-central Pacific, and below average in the eastern Pacific Ocean. ENSO-neutral is expected to continue for the next several months, with La Niña favored to emerge during September-November (66% chance) and persist through the Northern Hemisphere winter 2024-25 (74% chance during November-January).
Indian Sea Sate
Sea surface temperature around Sri Lanka was normal to the North Eastern and some parts of the Northern side of the country and 1.5℃ above average for the other half of the country from 23 July to 29 July 2024.
Interpretation
Monitoring
Rainfall: :During the last two weeks, there has been fairly heavy rainfall over the following area: Nochchiyagama ( Anuradhapura )
Daily Average Rainfall in the Met stations for the previous week of (8 - 14 Aug) = 6.6 mm
Maximum Daily Rainfall: 96.4 mm & Minimum Daily Rainfall: 0.0 mm.
Region | Average rainfall for 8 - 14 Aug (mm) | Average temperature for 8 - 14 Aug (ºC) | |
Maximum | Minimum | ||
Northern plains | 7.7 | 33.7 | 25.5 |
Eastern hills | 2.8 | 29.4 | 19.1 |
Eastern plains | 7.1 | 33.6 | 24.9 |
Western hills | 9.6 | 28.5 | 19.8 |
Western plains | 4.4 | 31.6 | 25.9 |
Southern plains | 1.5 | 31.4 | 25.9 |
Region | Average rainfall for 8 - 14 Aug (mm) | Daily maximum rainfall for 8 - 14 Aug (mm) | Daily minimum rainfall for 8 - 14 Aug (mm) |
All SL | 6.6 | 96.4 | 0.0 |
Hydro catchment | 7.5 | 65.0 | 0.0 |
Wind: North Westerly and 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 Western, Central and Sabaragamuwa province and below normal for some parts of the Eastern province for Sri Lanka driven by the warm SSTs.
Predictions
Rainfall: During the next week (15 - 21 Aug ), heavy rainfall (100 - 150 mm) is predicted for the Sabaragamuwa, Western, Uva, Central and Southern provinces and fairly heavy rainfall (50 – 100 mm) is predicted for the North Central, North Western and Eastern provinces and moderate rainfall (25-50 mm) is predicted for the Northern province.
Temperatures: The temperature will remain above normal for the Northern, Eastern and North Central provinces during 16 August - 22 August.
Teleconnections: MJO shall slightly enhance the rainfall during 15th – 24th August and near neutral the rainfall during 25th August – 29th August for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the September-October-November, 2024 season shows a 40% or more tendency toward normal precipitation for the country.
