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Friday, May 13, 2022

Climate Bulletin For Sri Lanka (13 May 2022)




 • NCEP GFS prediction for 11th onwards, the heaviest rainfall in Ratnapura, Galle &Kalutara districts is hazardous. Heavy rainfall above 100mm is expected  in Sabaragamuwa Wester, Southern & Central provinces.
 • During the last week, average daily rainfall over Sri Lanka was 4.4 mm and hydro catchment areas have received 9.4 mm on average.
 • From 2nd - 8th May, up to 10 m/s westerlies and South-westerlies were experienced over the Island.
 • Sea surface temperature was above 0.5℃ to the north and east of Sri Lanka. Land surface Temperature remained near normal during the last week.



14-day prediction: 
NOAA NCEP models: 
From 11th – 17th May
Total rainfall by Provinces:
  • >135 mm - Western, Southern, Sabaragamuwa
  • 105 mm - Central
  •   95 mm - North Western
  •   85 mm - Northern, North Central, Uva
  •   65 mm - Eastern
From 18th – 24th May
Total rainfall by Provinces:
  • 115 mm - Western, Southern
  • 105 mm - Sabaragamuwa
  •   75 mm - North Western, North Central
  •   65 mm - Uva, Northern, Central
  •   45 mm - Eastern
MJO based OLR predictions:
For the next 15 days: 
MJO shall neutral during 13th-15th May, shall moderately suppress the rainfall during 16th–20th May and severely suppress during 21st–25th May.

Ocean State (Text Courtesy IRI)
Pacific Sea Sate: May 4, 2022 
Equatorial sea surface temperatures (SSTs) are below average across the most of the Pacific Ocean in early-May. The tropical Pacific atmosphere is consistent with La Niña. A large majority of the models indicate La Niña is favored to continue into the Northern Hemisphere summer.

Indian Sea Sate
Sea surface temperature was above 0.5℃ to the North and East of Sri Lanka.


During the last two weeks, there had been heavy rainfall over the following area: 
Daily Average Rainfall in the Met stations for previous week of (2nd-9th May) 
=4.4 mm
Rmax: 105 mm & Rmin: 0.0 mm.


Average rainfall for the Last 8 days

Northern Plains

0.6 mm


3.6 mm


8.6 mm

Southern Plains

3.9 mm

The Hydro Catchment Areas recorded 9.4 mm of average rainfall for the last week
Rmax: 98 mm & Rmin: 0 mm. 

Westerly and South-westerly prevailed in the sea area surrounding the island last week. 
The temperature anomalies were above normal for the Western, Sabaragamuwa and North-western provinces and neutral for the rest of the country, driven by the warm SST’s.

During the next week (13th - 17th May) heavy rainfall (>100 mm) is predicted for the Western, Sabaragamuwa, Southern, and Central provinces. NCEP GFS prediction for 11th onwards, the heaviest rainfall expected in Ratnapura, Galle & Kalutara districts is hazardous.
The temperature remains slightly below normal in the Central, Uva & Sabaragamuwa provinces and above normal in the Eastern province during 6th - 14th May
La Nina - The SST forecast indicates that La Niña is favored to continue into the Northern Hemisphere summer (June-August 2022).
MJO shall neutral during 13th-15th May, shall moderately suppress the rainfall during 16th–20th May and severely suppress during 21st–25th May.

Seasonal Precipitation: 
The precipitation forecast for the May-June-July season shows below-normal precipitation for the island, but above-normal precipitation for the northern province.

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