Climate Bulletin For Sri Lanka (27 May 2022)

Highlights          

                   

 • Heavy  rainfall above 100 mm is expected  in Sabaragamuwa, Western and Southern  provinces during 25th - 31st May.

 • During the last week, the average daily rainfall over Sri Lanka was 4.5 mm and hydro catchment areas have received 11.1 mm on average.

 • From 16th - 22nd May, up to 20 m/s of south-westerlies were experienced over the island.

 • Sea surface temperature was observed to be below average of 0.5°C around the island. Land surface temperature remained near normal during the last week.

Download full report ↓

---

Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 

From 25^th – 31^st May: 

Total rainfall by Provinces:

• 115 mm - Western, Southern
• 105 mm - Sabaragamuwa
•  55 mm - North Western, Central
•  45 mm - Uva
•  25 mm - North Central, Eastern
•  15 mm - Northern

From 1^st – 7^th June: 

Total rainfall by Provinces:

• 135 mm - Southern, Western
• 115 mm - Sabaragamuwa
•  65 mm - Central, North Western, Uva
•  35 mm - North Central, Eastern 
•  25 mm - Northern

MJO based OLR predictions:

For the next 15 days: 

MJO shall neutral during 25^th - 29^th May; shall moderately suppress the rainfall during 30^th May – 3^rd June and significantly suppress the rainfall during 4^th – 8^th June.

Ocean State (Text Courtesy IRI)

Pacific Sea Sate: May 18, 2022 

Equatorial sea surface temperatures (SSTs) are below average across most of the Pacific Ocean in mid-May. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate, though La Niña is favored to continue, the odds for La Niña decrease into the late Northern Hemisphere summer before slightly increasing through the Northern Hemisphere fall and early winter 2022.

Indian Sea Sate

Sea surface temperature was observed to be below average of 0.5°C around the island.

Interpretation

Monitoring

Rainfall: 

During the last two weeks, there had been very heavy rainfall over the following area: Colombo

Daily Average Rainfall in the Met stations for previous week of (17^th - 24^th May) = 4.5 mm

Rmax: 105.7 mm & Rmin: 0.0 mm.

Region	Average rainfall for the Last 8 days
Northern Plains	3.4 mm
Eastern	0.05 mm
Western	9.0 mm
Southern Plains	1.6 mm

The Hydro Catchment Areas recorded 11.1 mm of average rainfall for the last week.

Rmax: 108 mm & Rmin: 0 mm. 

Wind:

South-westerly prevailed in the sea area surrounding the island last week. 

Temperature: 

The temperature anomalies were slightly below normal for the north central province, driven by the warm SST’s.

Predictions

Rainfall:

During the next week (27^th - 31^st May) heavy rainfall (>100 mm) is predicted for the Southern, Western and Sabaragamuwa provinces.

Temperature:

The temperature remains slightly above normal in the Northern and Eastern provinces and slightly below normal in the central province during 27^thMay - 4^th June. 

Teleconnections:

La Niña - Though La Niña is favored to continue, the odds for La Niña decrease into the late Northern Hemisphere summer (August-October 2022).

MJO shall neutral during 25^th - 29^th May; shall moderately suppress the rainfall during 30^th May – 3^rd June and significantly suppress the rainfall during 4^th – 8^th June.

Seasonal Precipitation: 

The precipitation forecast for the June-July-August season shows below-normal precipitation for the southern province and above-normal precipitation to the north province.