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Friday, June 21, 2019

Weekly Hydro-meteorological Report, 20, June 2019

Highlights

·  The IRI weekly rainfall forecast predicts up to 100 mm of total rainfall in Western province during 19 – 24 Jun.
·  Between 11 – 17 Jun: up to 50 mm of rainfall was recorded in Colombo district on the 11th.
·  From 11 – 17 Jun: up to 54 km/h, westerly winds were experienced by the entire island.
·  1 0C above average sea surface temperature was observed in the seas around Sri Lanka.




Monitoring

Weekly Monitoring: No significant rainfalls were recorded in any part of the island on June 12th. On June 13th, Jaffna and Kilinochchi districts received up to 30 mm of rainfall; and Mullaitivu district up to 20 mm.  On the 14th, Colombo district received up to 30 mm of rainfall; and Puttalam, Gampaha, Kegalle, Ratnapura and Kegalle districts up to 20 mm. No significant rainfalls were recorded in any part of the island on the 15th. On the 16th, Kurunegala, Anuradhapura, Matale, Polonnaruwa, Batticaloa, Ratnapura and Matara districts received up to 5 mm of rainfall. On the 17th, Vavuniya, Batticaloa, Ampara, Monaragala, Badulla, Kegalle, Colombo and Galle districts received up to 5 mm of rainfall.


Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 10-25 mm in Jaffna, Kilinochchi, Mullaitivu, Puttalam, Gampaha, Colombo, Kalutara, Ratnapura, Nuwara Eliya and Batticaloa districts; and 5-10 mm in most parts of the island. Below average rainfall up to 25-50 mm is shown for Kurunegala, Kandy, Nuwara Eliya and Badulla districts; and up to 10-25 mm in most parts of the island.

Monthly Monitoring: During May – Below average rainfall conditions up to 240 mm were experienced by Nuwara Eliya, Kegalle, Colombo, Kalutara, Gampaha, Kurunegala and Ratnapura districts; and up to 180 mm in rest of the island. The CPC Unified Precipitation Analysis tool shows up to 150 mm of total rainfall in Colombo, Kalutara and Galle districts; up to 100 mm in Gampaha, Kegalle, Ratnapura, Matara, Badulla, Monaragala and Galle districts; up to 75 mm in Trincomalee, Polonnaruwa, Nuwara Eliya, Ampara and Hambantota districts; and up to 50 mm in Vavuniya, Anuradhapura, Puttalam, Kurunegala, Matale and Kandy districts. 


Predictions


Rainfall

14-day prediction: 
NOAA NCEP models: 
From 19th – 25th Jun: Total rainfall up to 55 mm Puttalam, Gampaha, Kegalle, Colombo, Ratnapura and Galle districts; up to 35-45 mm in Kurunegala, Nuwara Eliya and Matara districts; and up to 15-25 mm in most parts of the island.
From 25th Jun -2nd Jul: Total rainfall up to 25 mm in Puttalam, Gampaha and Ratnapura districts; and up to 5-15 mm Kurunegala, Kegalle, Galle and Matara districts.

IMD NCMWRF Forecast: 
21st Jun: Not Available

22nd Jun: Not Available

IRI Model Forecast: 
From 22nd – 27th May: 
From 19th – 24th Jun: Total rainfall up to 100 mm is expected in Gampaha, Colombo and Kalutara districts; up to 75 mm in Puttalam, Kurunegala, Kegalle, Tatnapura and Galle districts; and up to 50 mm in Kandy, Nuwara Eliya, Matara and Hambantota districts.


MJO based OLR predictions:
For the next 15 days:
MJO shall not have an impact on the rainfall in Sri Lanka in the next 10 days and shall suppress in the following 5 days. 

Ocean State (Text Courtesy IRI)
Pacific sea state: June 19, 2019
SSTs in the tropical Pacific maintained a weak El Niño level during May and early June, and temperature anomalies of subsurface waters were slightly above average. Some patterns in the atmosphere show intermittent El Niño conditions. Collective model forecasts show a continuation of at least weak El Niño-level SSTs lasting through 2019. The official CPC/IRI outlook, with an El Niño advisory, calls for a 66% chance of El Niño continuing during Jun-Aug, decreasing to 50-55% for continuing through fall and winter.
Indian Ocean State

1 0C above average sea surface temperature was observed in the seas around Sri Lanka.

Tuesday, June 18, 2019

Real-time flood monitoring in Sri Lanka

Real-time flood monitoring in Sri Lanka


By Dimithri Wijesinghe and Chenelle Fernando                                    Read Full Article Here


The Centre for Urban Water Sri Lanka of the Metro Colombo Urban Development Project (MCUDP) has a system underway to monitor floods in real time.

According to engineer and Project Director Thushari Andra Hannadige, the real-time warning system has already been implemented through a pilot project. She said: “The project will reach full completion by June, 2020, with the completion of other factorial interventions.” These, according her, include the construction of pumping stations, tunnels, and floodgates.

We spoke to the Team Leader of the MCUDP Prof. Sri Kantha Herath about the real-time monitoring system for floods and other projects underway in order to make Colombo a sustainable city, resistant to flooding.

According to Herath, Colombo city often falls victim to urban flooding caused by excessive rains, resulting in the available drainage systems being insufficient.

“Currently, the system includes four drainage ways, three into the sea, and one to the river (Kelani River). However, in the past 30 years, we’ve had eight major floods and that’s been due to the Kelani River overflowing, thereby being unable to contain the excess being drained from the city.”

Urban flooding is often caused due to a lack of drainage in an urban area, and as there is little open soil that can be used for water storage, nearly all the precipitation needs to be transported to surface water or the sewage system.

High intensity rainfall can cause flooding when the city sewage system and draining canals do not have the necessary capacity to drain away the amounts of rain that are falling. Water may even enter the sewage system in one place and then get deposited somewhere else in the city.

Herath discussed other cities which have undergone severe urban flooding disasters, such as Beijing in China, which is a city that has a high land value and therefore, construction of drainage is near impossible and so the city finds it extremely difficult to drain water.

There’s also Tokyo, which has an underground river; the same has been adopted by Bangkok, Malaysia, and Singapore by building underground tunnels. However, these are very expensive alternatives – expenses that are overwhelming for a country like ours, and we are, thankfully, not at a level where we require such extreme measures; that is if we utilise our available resources.

For this issue, there have been various steps undertaken under the purview of the Ministry of Megapolis and Western Development. One such solution includes the implementation of two strategic micro tunnels, one of which is situated in Torrington and was very recently executed.

The Irrigation department too has a World Bank project in place, looking into alternative options to contain water in the Kelani River to prevent it from overflowing.

There are further steps taken and implemented by the Colombo municipality with regard to building and planning, which requires all establishments coming up to satisfy a certain requirement of water retention. Then, there is the utilising of Colombo’s wetlands, which are a natural resource – an ideal solution to urban flooding; there is a system underway to optimise the utilising of wetlands.

As for the monitoring system, its main job remains to forecast rain level in the city in order to estimate the best operational system. Referring to such a system for the purpose of creating such a database, which is able to forecast accurately, Herath said: “We need a dense network of monitoring systems, and we should be able to couple them with the rain level and other information. We need to read this data quickly, and so we do it in real time via an internet of pings; it is also very cost effective.”

Herath added that currently, additional rain gauges (30 currently) are being installed as a final measure, including other gauges to measure humidity. The data acquired will be transmitted to their computer model which is not inclusive of a human interface and the data collected is an open source and will be available to everyone. He said: “The system is largely done now, and with the installation of output measures, we can calibrate.”

Tuesday, June 11, 2019

Weekly Hydro-meteorological Report, 6, June 2019

Highlights 







Monitoring


Weekly Monitoring: On May 28th, Gampaha, Colombo, Kalutara and Galle districts received up to 10 mm of rainfall. No significant rainfalls were recorded in any part of the island on the 29th. On the 30th, Kalutara, Ratnapura, Galle and Matara districts received up to 20 mm of rainfall. On the 31st, Polonnaruwa and Ampara districts received up to 20 mm of rainfall. On June 1st, Kilinochchi, Puttalam, Kurunegala, Anuradhapura, Polonnaruwa, Matale, Gampaha, Kegalle, Colombo, Kalutara, Galle and Ratnapura districts received up to 5 mm of rainfall. On the 2nd, Anuradhapura district received up to 5 mm of rainfall. On the 3rd, Kalutara and Matara districts received up to 40 mm of rainfall; Puttalam, Kurunegala, Gampaha, Colombo, Ratnapura, Badulla, Hambantota and Monaragala districts up to 30 mm; and Kegalle, Kandy Nuwara Eliya, Kilinochchi and Jaffna districts up to 20 mm. On the 4th, Badulla, Monaragala, Ampara and Kurunegala districts received up to 50 mm of rainfall; Puttalam, Gampaha, Ratnapura, Kegalle and Kandy districts up to 30 mm; and Vavuniya, Mullaitivu, Polonnaruwa, Colombo, Kalutara, Galle, Matale and Nuwara Eliya districts up to 20 mm.


Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 50-75 mm in Kalutara, Ratnapura and Galle districts; up to 25-50 mm in Gampaha, Colombo, Kurunegala, Puttalam, Kegalle, Kandy, Nuwara Eliya, Matara, Hambantota, Ampara, Badulla and Monaragala districts; and 10-25 mm in Mannar, Anuradhapura Polonnaruwa, Matale and Batticaloa districts. Above average rainfall up to 25-50 mm is shown for Ampara and Badulla districts; and up to 10-25 mm in Puttalam, Kurunegala, Anuradhapura, Kegalle, Kalutara, Ratnapura, Galle, Matara and Monaragala districts.


Monthly Monitoring: During May – Below average rainfall conditions up to 240 mm were experienced by Nuwara Eliya, Kegalle, Colombo, Kalutara, Gampaha, Kurunegala and Ratnapura districts; and up to 180 mm in rest of the island. The CPC Unified Precipitation Analysis tool shows up to 150 mm of total rainfall in Colombo, Kalutara and Galle districts; up to 100 mm in Gampaha, Kegalle, Ratnapura, Matara, Badulla, Monaragala and Galle districts; up to 75 mm in Trincomalee, Polonnaruwa, Nuwara Eliya, Ampara and Hambantota districts; and up to 50 mm in Vavuniya, Anuradhapura, Puttalam, Kurunegala, Matale and Kandy districts.

Predictions


Rainfall


14-day prediction: 
NOAA NCEP models: 
From 5th – 11th Jun: Total rainfall up to 75 mm Galle and Matara districts; up to 55-65 mm in Kalutara and Hambantota districts; up to 45-55 mm in Colombo district; and up to 35-45 mm in Gampaha, Kegalle, Nuwara Eliya, Badulla, Monaragala and Ampara districts.

From 12th – 18th Jun: Total rainfall up to 55 mm in Ratnapura, Galle and Matara districts; up to 35-45 mm in Gampaha and Hambantota districts; up to 25-35 mm Puttalam, Kurunegala, Nuwara Eliya, Badulla and Monaragala districts.

IMD NCMWRF Forecast: 

7th jun: Not Available
8th Jun: Not Available

IRI Model Forecast: 

From 5th – 10th Jun: Total rainfall up to 200 mm is expected in Kalutara and Galle districts; up to 150 mm in Gampaha, Colombo, Kegalle, Ratnapura and Matara districts; up to 100 mm in Puttalam, Kurunegala, Nuwara Eliya and Hambantota districts; and up to 75 mm in Kandy district.

MJO based OLR predictions:

For the next 15 days: MJO shall enhance the rainfall in Sri Lanka. 


Ocean State (Text Courtesy IRI)

Pacific sea state: May 20, 2019
SSTs in the tropical Pacific maintained a weak El Niño level during April and early May, while temperature anomalies of subsurface waters decreased markedly to just slightly above average. Some patterns in the atmosphere show weak El Niño conditions. Collective model forecasts show a continuation of at least weak El Niño-level SSTs lasting through 2019. The official CPC/IRI outlook, with an El Niño advisory, calls for an approximate 70% chance of El Niño continuing during Jun-Aug, decreasing to 55-60% for Sep-Nov.

Indian Ocean State



0.5 0C above average sea surface temperature was observed in the seas around Sri Lanka.

Friday, May 31, 2019

Weekly Hydro-meteorological Report, 30, May 2019

Highlights
  • The IRI weekly rainfall forecast predicts up to 50 mm of total rainfall in western and central parts of the island during 29 May – 3 Jun.
  • Between 21 - 27 May: up to 60 mm of rainfall was recorded in Colombo district on the 23rd.
  • From 21 - 27 May: up to 36 km/h, westerly winds were experienced by the entire island.
  • 0.5 0C below average sea surface temperature was observed in the southern seas around Sri Lanka.



Monitoring

Weekly Monitoring:On May 21st, Jaffna and Kilinochchi districts received up to 10 mm of rainfall. On the 22nd, Nuwara Eliya district received up to 20 mm of rainfall; and Galle and Hambantota districts up to 10 mm. On the 23rd, Colombo district received up to 60 mm of rainfall; Gampaha and Kalutara district up to 50 mm; Trincomalee, Polonnaruwa, Kegalle, Ratnapura and Galle districts up to 30 mm; and Puttalam, Anuradhapura, Kandy and Matara districts up to 20 mm. On the 24th, Colombo district received up to 30 mm of rainfall; and Gampaha, Kegalle, Ratnapura, Kalutara, Galle, Badulla and Monaragala districts up to 20 mm. On the 25th, Ampara, Galle and Matara districts received up to 20 mm of rainfall. On the 26th, Puttalam district received up to 20 mm of rainfall; and Colombo district up to 10 mm. No significant rainfalls were recorded in any part of the island on the 27th.

Total Rainfall for the Past Week: TThe RFE 2.0 tool shows total up to 75-100 mm in Colombo district; up to 50-75 mm in Gampaha and Kalutara districts; up to 25-50 mm in Kegalle, Ratnapura, Galle, Matara, Trincoalee and Badulla districts; and 10-25 mm in Polonnaruwa, Matale, Kandy, Nuwara Eliya, Monaragala, Puttalam, Kurunegala and Hambantota districts. Above average rainfall up to 25-50 mm is shown for Trincomalee, Polonnaruwa and Colombo districts. Below average rainfall up to 25-50 mm is shown for Kurunegala, Kandy, Nuwara Eliya, Ratnapura, Galle, Badulla, Monaragala and Ampara districts; and up to 10-25 mm in Matale, Puttalam, Kegalle, Matara and Hambantota districts.

Monthly Monitoring: During April – Above average rainfall conditions up to 60 mm were experienced in western regions of Kurunegala district and central regions of Anuradhapura district. Below average rainfall conditions up to 240 mm were experienced by Matale, Kandy, Nuwara Eliya, Kegalle, Colombo, Kalutara, Galle, Matara, Ratnapura, Hambantota, Badulla and Monaragala districts; and up to 180 mm in rest of the island. The CPC Unified Precipitation Analysis tool shows up to 500 mm of total rainfall in Gampaha district; up to 300 mm in Puttalam, Kurunegala, Anuradhapura, Kegalle, Ratnapura, Colombo, Kalutara and Galle districts; up to 200 mm in Matale, Kandy, Nuwara Eliya and Matara districts; and up to 100 mm in Mannar, Vavuniya, Polonnaruwa, Badulla, Monaragala, Batticaloa, Ampara and Hambantota districts.

Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 29th May – 4th Jun: Total rainfall up to 55 mm Ratnapura and Matara districts; up to 35-45 mm in Hambantota district; and up to 25-35 mm in Colombo and Gampaha districts.

From 5th – 11th Jun: Total rainfall up to 55 mm in Ratnapura, Galle districts; up to 35-45 mm in Ratnapura and Matara districts; up to 25-35 mm in Colombo, Gampaha, Kegalle and Hambantota districts.

IMD NCMWRF Forecast: 
31st May: Not Available
1st Jun: Not Available

IRI Model Forecast: 
From 29th May – 3rd Jun: Total rainfall up to 50 mm is expected in Nuwara Eliya, Kandy, Badulla, Kegalle, Ratnapura, Gampaha, Colombo, Kalutara, Galle and Matara districts. MJO based OLR predictions For the next 15 days: MJO shall suppress the rainfall in Sri Lanka in the next 5 days and shall enhance in the following 10 days.


MJO based OLR predictions:
For the next 15 days: MJO shall enhance the rainfall in Sri Lanka.

Ocean State (Text Courtesy IRI)
Pacific sea state: May 20, 2019
SSTs in the tropical Pacific maintained a weak El Niño level during April and early May, while temperature anomalies of subsurface waters decreased markedly to just slightly above average. Some patterns in the atmosphere show weak El Niño conditions. Collective model forecasts show a continuation of at least weak El Niño-level SSTs lasting through 2019. The official CPC/IRI outlook, with an El Niño advisory, calls for an approximate 70% chance of El Niño continuing during Jun-Aug, decreasing to 55-60% for Sep-Nov.

Indian Ocean State
0.5 0C below average sea surface temperature was observed in the southern seas around Sri Lanka.

Friday, May 24, 2019

Weekly Hydro-meteorological Report, 23, May 2019

Highlights
  • The IRI weekly rainfall forecast predicts up to 75 mm of total rainfall in Kandy, Badulla and Nuwara Eliya districts during 22 – 27 May.
  • Between 14 - 21 May: up to 50 mm of rainfall was recorded in Monaragala district on the 16th and 17th.
  • From 14 - 20 May: up to 36 km/h, westerly winds were experienced by the central and southern regions of the island.
  • Average sea surface temperature was observed in the seas around Sri Lanka.



Monitoring

Weekly Monitoring: On May 14th, Kalutara, Galle and Matara districts received up to 10 mm of rainfall. On the 15th, Polonnaruwa, Ampara and Badulla districts received up to 20 mm of rainfall; and Galle and Matara districts up to 10 mm. On the 16th, Badulla, Monaragala and Ampara districts received up to 50 mm of rainfall; Galle, Kandy and Matale districts up to 20 mm; and Kalutara and Polonnaruwa districts up to 10 mm. On the 17th, Badulla, Monaragala and Ampara districts received up to 10 mm of rainfall. On the 18th, Badulla, Monaragala, Ratnapura, Polonnaruwa, Hambantota and Matara districts received up to 20 mm of rainfall; and Kegalle and Ampara districts up to 10 mm. On the 19th, Monaragala district received up to 50 mm of rainfall; Kandy and Colombo districts up to 20 mm; and Kegalle, Ratnapura and Nuwara Eliya districts up to 10 mm. On the 20th, Vavuniya district received up to 30 mm of rainfall; Mullaitivu and Anuradhapura districts up to 20 mm; and Kalutara and Badulla districts up to 10 mm. On the 21st, Jaffna and Kilinochchi districts received up to 10 mm of rainfall

Total Rainfall for the Past Week: The RFE 2.0 tool shows total up to 50-75 mm in Badulla and Monaragala districts; up to 25-50 mm in Ampara district; and 10-25 mm in Vavuniya, Anuradhapura, Polonnaruwa, Matale, Kandy, Nuwara Eliya, Kegalle, Gamapaha, Colombo, Kalutara, Ratnapura, Galle and Matara districts. Above average rainfall up to 25-50 mm is shown for Northern regions of Monaragala district; and up to 10-250 mm in Badulla and Vavuniya districts. Below average rainfall up to 50-100 mm is shown for Gampaha, Colombo, Kalutara and Ratnapura districts; up to 25-50 mm in Puttalam, Kurunegala, Kegalle, Nuwara Eliya, Galle, Matara and Hambantota districts; and up to 10-25 mm in Matale, Kandy and Southern regions of Monaragala districts

Predictions

Rainfall

14-day prediction: 
NOAA NCEP models: 
From 22nd – 28th May: Total rainfall up to 55 mm Matara and Galle districts; up to 35-45 mm in Ratnapura and Hambantota districts; and up to 25-35 mm in Colombo and Monaragala districts. From 29th May – 4th Jun: Total rainfall up to 75 mm in Ratnapura, Galle and Matara districts; up to 55-65 mm in Kalutara district; up to 35-45 mm in Gampaha, Kegalle and Monaragala districts; up to 25-35 mm in Jaffna, Kilinochchi, Vavuniya and Mullaitivu districts; and up to 5-15 mm most parts of the island.

IMD NCMWRF Forecast: 
24th May: Not Available
25th May: Not Available

IRI Model Forecast: 
From 22nd – 27th May: 
Total rainfall up to 75 mm is expected in Nuwara Eliya, Kandy and Badulla districts; and up to 50 mm in Polonnaruwa, Matale, Kegalle, Ratnapura, Kalutara, Galle, Matara, Batticaloa, Monaragala and Ampara districts. MJO based OLR predictions For the next 15 days: MJO shall suppress the rainfall in Sri Lanka in the next 5 days and shall enhance in the following 10 days.


MJO based OLR predictions:
For the next 15 days:
MJO shall suppress the rainfall in Sri Lanka in the next 5 days and shall enhance in the following 10 days.

Ocean State (Text Courtesy IRI)
Pacific sea state: May 20, 2018
SSTs in the tropical Pacific maintained a weak El Niño level during April and early May, while temperature anomalies of subsurface waters decreased markedly to just slightly above average. Some patterns in the atmosphere show weak El Niño conditions. Collective model forecasts show a continuation of at least weak El Niño-level SSTs lasting through 2019. The official CPC/IRI outlook, with an El Niño advisory, calls for an approximate 70% chance of El Niño continuing during Jun-Aug, decreasing to 55-60% for Sep-Nov.
Indian Ocean State
Average sea surface temperature was observed in the seas around Sri Lanka.

Thursday, May 16, 2019

Weekly Hydro-meteorological Report, 16, May 2019

Highlights:

  •   The IRI weekly rainfall forecast predicts up to 75 mm of total rainfall in Badulla and Nuwara Eliya districts during 15 – 20 May.
  •   Between 7 - 13 May: up to 90 mm of rainfall was recorded in Trincomalee district on the 12th.
  •  From 7 - 13 May: up to 36 km/h, westerly winds were experienced by the central and southern regions of the island.
  •   Average sea surface temperature was observed in the seas around Sri Lanka.
Download Full Report

Thursday, May 9, 2019

Weekly Hydro-meteorological Report, 9, May 2019

Highlights:

  •   The IRI weekly rainfall forecast predicts up to 25 mm of total rainfall in the entire island during 8 – 13 May.
  •   Between 30 Apr - 6 May: up to 90 mm of rainfall was recorded in Galle and Matara districts on the 3rd.
  •  From 30 Apr - 6 May: up to 36 km/h, westerly winds were experienced by the entire island.
  •   0.5 0C above average sea surface temperature was observed in the eastern seas around Sri Lanka.
Download Full Report