Highlights
• Light showers (25 mm) are predicted for the Sabaragamuwa, Southern, Northern, Uva provinces during 24 - 30 Aug. Fairly heavy rainfall (≥ 55mm) is predicted for the Sabaragamuwa, Southern, Western, Uva, Central, North Western provinces during 31 Aug - 6 Sep.
• During the last week, average daily rainfall over Sri Lanka was 'light' (0.9 mm) and hydro catchment areas received 'light' (1.2 mm) showers.
• From 15 - 21 Aug, up to 10 m/s of northwest-westerly winds were at 850 mb (1.5 km). During 25 - 31 Aug, up to 10 m/s of northwest-southwesterly winds are expected at 850 mb (1.5 km).
• Sea surface temperature around Sri Lanka was
0.5 - 2ºC above normal. From 16 - 23 Aug, maximum daily temperature
was recorded in Vavuniya (38.5ºC),
Polonnaruwa (38.1ºC) and Pottuvil (37.5ºC).
Predictions
Rainfall
14-day prediction:NOAA NCEP models:
From 24th August – 30th August:
Total rainfall by Provinces
- 25mm - Southern, Sabaragamuwa, Northern, Uva
- ≤ 15mm - Central, Eastern, Western, North Central, North Western
From 31st August – 6th September:
Total rainfall by Provinces
- 85mm - Southern
- 75mm - Sabaragamuwa, Western
- 65mm - Uva, Central
- 55mm - North Western
- 45mm - Eastern
- ≤ 35mm - North Central, Northern
MJO based OLR predictions:
For the next 15 days:
MJO shall near
neutral the rainfall during 23rd August - 1st September
and slightly enhance the rainfall during 2nd - 6th September
for Sri Lanka.
Ocean State (Text Courtesy IRI)
Pacific Sea Sate: August 21, 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-August.
El Niño conditions will continue through the Northern Hemisphere winter (with greater than a 95% chance
through December 2023-February 2024).
Interpretation
Monitoring
Rainfall:
During the last two weeks, there had been fairly heavy rainfall over the following area: Polonnaruwa
Daily
Average Rainfall in the Met stations for
previous week of (16th August - 23rd August) = 0.9 mm
Maximum Daily Rainfall: 29.8 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 |
0.4 |
34.4 |
26.2 |
|
Eastern hills |
0.2 |
30.2 |
18.2 |
|
Eastern
plains |
1.1 |
35.8 |
25.1 |
|
Western
hills |
1.0 |
29.2 |
20.0 |
|
Western
plains |
1.6 |
32.2 |
26.7 |
|
Southern
plains |
0.8 |
33.5 |
25.3 |
|
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 |
1.2 |
46.2 |
0.0 |
Wind: Northwest-westerly winds prevailed in the sea area and around the island last week.
Temperatures: The temperature anomalies were above normal for the Western, Sabaragamuwa provinces and some parts of the Southern, Central, Uva, and North Western provinces of the country driven by the warm SST’s.
Predictions
Rainfall: During the next week (24th August
- 30th August), light showers (25 mm) are predicted for the Southern, Sabaragamuwa, Northern, and
Uva 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, Southern, and Central provinces during 25th August - 31st
August.
Teleconnections:
A positive Dipole Mode has set in across the Indian Ocean since 8th
of June.
MJO shall near neutral the
rainfall during 23rd August - 1st September and slightly
enhance the rainfall during 2nd - 6th September for Sri
Lanka.
Seasonal Precipitation: The precipitation
forecast for the September-October-November, 2023 season shows above normal
precipitation for the country.
