Highlights
• Due to the low pressure area over southwest
Bay of Bengal, fairly heavy rainfall is predicted for the Eastern, Sabaragamuwa and Western provinces during 22nd - 28th
December. Seasonal forecast shows higher tendency for
above normal precipitation to the country for
January - March, 2023.
• During the last week, maximum daily rainfall
over Sri Lanka was 106.6 mm & hydro catchment areas received 83.0 mm on
maximum and the highest average rainfall (10.1 mm) was received
Eastern plains of the country.
• From 13th - 19th Dec, up to 8m/s of north easterly winds were experienced at 850 mb level over the
island. Strong winds and rough seas are expected for following days due to the
effect of low pressure area in vicinity of the country
• Sea surface temperature around Sri Lanka was
above normal to the western, eastern, and southern half of the country. Land surface temperature remained near normal
Predictions
Rainfall
14-day prediction:NOAA NCEP models:
From 22nd December – 28th December:
Total rainfall by Provinces:
- 55 mm - Eastern, Western, Sabaragamuwa
- 45 mm - Northern, Central, Southern, North Western, North Central, Uva
From 29th December – 4th January:
Total rainfall by Provinces:
- 35 mm - Eastern
- 25 mm - Western, North Central, Northern
- ≤ 15 mm - Southern, Sabaragamuwa, Central, North Western, Uva
MJO based OLR predictions:
For the next 15 days:
MJO shall near neutral the rainfall during 22nd
December – 26th December, and moderately suppress the rainfall
during 27th December – 5th January for Sri Lanka.
Ocean State (Text Courtesy IRI)
Pacific Sea Sate: December 19, 2022
Equatorial
sea surface temperatures (SSTs) are below average across most of the Pacific
Ocean mid - December. The tropical Pacific atmosphere is consistent with La Niña. A
large majority of the models indicate La Niña is favored to continue into the
winter, with equal chances of La Niña and ENSO-neutral during January-March
2023. In February-April 2023, there is a 71% chance of ENSO-neutral.
Indian Sea Sate
Sea surface temperature around Sri
Lanka was above 0.5℃ to
the western, eastern, and southern half of the country in 30th November,
2022. Across the Indian
Ocean, a classical negative Indian Ocean Dipole prevails as is typical during a
La Niña.
Interpretation
Monitoring
Rainfall:
During
the last two weeks, there had been very heavy rainfall over the
following area: Trincomalee
Daily Average Rainfall in the Met stations for previous week of (13th December – 20th December) =
7.7 mm
Rmax: 106.6 mm & Rmin: 0.0 mm.
Region | Average rainfall for the Last 8 days |
Northern Plains | 7.5 mm |
Eastern | 10.1 mm |
Western | 6.0 mm |
Southern Plains | 3.8 mm |
The Hydro Catchment Areas recorded 8.1 mm of average rainfall for the last week
Rmax: 83.0 mm & Rmin: 0.0 mm.
Wind:
North easterly winds prevailed in the sea area
and around the island last week.
Temperature:
The temperature anomalies
were below normal for some parts of the North Western, North Central, and
Central provinces, driven by the warm
SST’s.
Predictions
Rainfall:
During the next week (22nd Dec
– 28th Dec), fairly heavy rainfall is predicted for the Eastern,
Western, and Sabaragamuwa provinces; and
≥ 45 mm rainfall is expected for the rest of
the country.
Temperature:
The temperature will remain below normal for some
parts of the Central, Uva, and Sabaragamuwa provinces during 23rd – 29th December.
Teleconnections:
La
Niña is favored to continue into the winter, with equal chances of La Niña and
ENSO-neutral during January-March 2023.
MJO shall near neutral the rainfall during
22nd December – 26th December, and moderately suppress
the rainfall during 27th December – 5th January for Sri
Lanka.
Seasonal Precipitation:
The precipitation
forecast for the January-February-March 2023 season shows a higher tendency for
above-normal precipitation to the country.
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