Highlights
• Heavy rainfall (≥ 115 mm) is predicted for
the Southern, Sabaragamuwa, Western, Uva, Central provinces and fairly heavy
rainfall (85 mm) is predicted for the North Western, Eastern provinces during 26 Sep - 2 Oct.
• During
the last week, average daily rainfall over Sri Lanka was 13.3 mm and
hydro catchment areas received 5.3 mm. Highest average rainfall of 17.6 mm/day
received Western plains.
• From 17 - 23 Sep, up to 10 m/s of
northwest-southwesterly winds were at 850 mb (1.5 km). During 27 Sep - 3 Oct, up to 15 m/s of
west-southwesterly winds are expected at 850 mb (1.5 km).
• Sea surface temperature around Sri Lanka was
0.25 - 1.5ºC above normal. From 18 - 25 Sep, maximum daily temperature
was recorded in Polonnaruwa (38.3ºC) and
Vavuniya (36.9ºC).
Predictions
Rainfall
14-day prediction:NOAA NCEP models:
From 26th September - 2nd October:
Total rainfall by Provinces
- ≥ 135 mm - Southern, Sabaragamuwa, Western
- 125 mm - Uva
- 115 mm - Central
- 85 mm - North Western, Eastern
- 35 mm - North Central
- ≤ 25 mm - Northern
From 3rd October - 9th October:
Total rainfall by Provinces
- ≥ 135 mm - Southern, Sabaragamuwa, Western, Uva
- 115 mm - Central
- 85 mm - Eastern
- 75 mm - North Western
- 35 mm - North Central
- ≤ 15 mm - Northern
MJO based OLR predictions:
For the next 15 days:
MJO shall near neutral the
rainfall during 26th September - 10th October for
Sri Lanka.
Ocean State (Text Courtesy IRI)
Pacific Sea Sate: September 25, 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 late-September.
El Niño conditions will continue through the Northern Hemisphere winter (with greater than a 95% chance
through January - March 2024).
Interpretation
Monitoring
Rainfall:
During the last two weeks, there had been very heavy rainfall over the following area: Galle
Daily Average Rainfall in the Met stations for previous week of (18th September - 25th September) = 13.3 mm
Maximum Daily Rainfall: 95.0 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 |
2.8 |
33.1 |
25.7 |
|
Eastern hills |
14.5 |
27.7 |
18.4 |
|
Eastern plains |
7.2 |
34.0 |
24.5 |
|
Western hills |
7.9 |
27.2 |
19.4 |
|
Western plains |
17.6 |
30.5 |
24.7 |
|
Southern plains |
3.9 |
31.5 |
24.6 |
|
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 |
5.3 |
53.0 |
0.0 |
Wind: Northwest-southwesterly winds prevailed in the sea area and around the island last week.
Temperatures: The
temperature anomalies were above normal for some parts of the Northern and Uva
provinces of the country driven by the warm
SST’s.
Predictions
Rainfall: During the next week (26th September - 2nd October), heavy rainfall (≥ 115 mm) is predicted for
the Southern,
Sabaragamuwa, Western, Uva, and Central provinces and fairly heavy rainfall (85 mm) is predicted for the North
Western and Eastern provinces and less rainfall is predicted for the rest of
the country.
Temperatures: The temperature will remain above normal for some
parts of the Northern and Eastern provinces and below normal for some parts of
the Central province during 27th September - 3rd October.
Teleconnections: A positive Dipole Mode has set in across the Indian Ocean since 8th
of June. MJO shall near neutral the rainfall during
26th September - 10th October for Sri Lanka.
Seasonal Precipitation: The precipitation
forecast for the October-November-December, 2023 season shows a 50 - 60%
tendency toward above normal precipitation for the country.
