Highlights
• High likelihood of fairly heavy rainfall is predicted for Northern, Eastern, North Central, Southern, Sabaragamuwa, Uva, Central provinces during 20 - 26 Dec. Extreme rainfall is predicted during following week.
• During the last week, average daily rainfall over Sri Lanka was 20.9 mm and hydro catchment was 21.9 mm. Extreme rainfall (> 150 mm/day) was in Northern province. The rainfall of last week was twice as normal.
• From 11 - 17 Dec, up to 8 m/s of easterly winds were at 850 mb (1.5 km). During 21 - 27 Dec, up to 8 m/s of north easterly winds are expected at 850 mb (1.5 km).
• Sea surface temperature around Sri Lanka was 0.25 - 1.5ºC above normal. Strong EL Nino patterns sustain.
Predictions
Rainfall
7-day prediction:NOAA NCEP models:
From 20th December - 26th December:
Total rainfall by Provinces
- 85 mm - Northern, Eastern
- 75 mm - North Central
- 55 mm - Southern, Sabaragamuwa, Uva, Central
- 45 mm - Western
- 35 mm - North Western
MJO based OLR predictions:
For the next 15 days:
MJO shall near normal the rainfall during 20th - 24th December, slightly enhance the rainfall during 25th - 29th December and near normal the rainfall during 30th December - 3rd January for Sri Lanka.
Ocean State (Text Courtesy IRI)
Pacific Sea Sate: December 18, 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-December. El Niño is expected to continue through the Northern Hemisphere winter, with a transition to ENSO-neutral favored during April-June 2024 (60% chance).
Interpretation
Monitoring
Rainfall: During the last two weeks, there had been very heavy rainfall over the following area: Mullaitivu.
Daily Average Rainfall in the Met stations for previous week of (13th December - 20th December) = 20.9 mm
Maximum Daily Rainfall: 153.3 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 | 25.7 | 28.7 | 24.4 |
Eastern hills | 14.9 | 24.6 | 19.4 |
Eastern plains | 27.5 | 29.2 | 24.4 |
Western hills | 15.6 | 26.8 | 19.9 |
Western plains | 12.3 | 31.0 | 24.5 |
Southern plains | 26.6 | 30.3 | 24.4 |
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 | 21.9 | 103.2 | 0.0 |
Wind: Easterly winds prevailed in the sea area and around the island last week.
Temperatures: The temperature anomalies were above normal for some parts of the Central, Sabaragamuwa, and Western provinces of the country driven by the warm SST’s.
Predictions
Rainfall: During the next week (20th December - 26th December), fairly heavy rainfall is predicted for the Northern, Eastern, North Central, Southern, Sabaragamuwa, Uva, Central provinces and less rainfall is predicted for rest of the country.
Temperatures: The temperature will remain seasonably near normal for the country during 21st December - 27th December.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th of June.
MJO shall near normal the rainfall during 20th - 24th December, slightly enhance the rainfall during 25th - 29th December and near normal the rainfall during 30th December - 3rd January for Sri Lanka.
Seasonal Precipitation: The precipitation forecast for the January-February-March, 2024 season shows near normal precipitation.
