Ocean Forecasts

Ocean forecasts for the Estuary and Gulf of St. Lawrence are produced by the Operational Oceanography scientific team of Fisheries and Oceans Canada, Maurice Lamontagne Institute, Mont-Joli, Québec.

Important Notices – Surface Currents, Surface Temperature, Sea Ice, Water Level

Gulf of St. Lawrence
48 hour forecasts

The forecasts of surface currents, surface temperature, and sea ice in the Gulf of St. Lawrence result from a three-dimensional numerical model coupled to the Canadian Meteorological Service’s atmospheric forecast model (Environment and Climate Change Canada) (Smith et al. 2013, Pellerin et al. 2004, Saucier et al. 2003). The ocean model integrates the influence of tides, freshwater runoff, atmospheric forcing, and sea ice. The two models—oceanic and atmospheric—provide daily forecasts for the upcoming 48 hours. The ocean model results have been validated within the scientific and operational programs of Fisheries and Oceans Canada. The validation included a number of comparisons with various ocean measurements: currents, water levels, water temperature and salinity, and sea-ice drift as well as its concentration and thickness. The model has been validated under a series of scientific and operational research and development programs within the Department of Environment and Climate Change Canada.

The model’s forcing data include:

  • Tides at Cabot and Belle-Isle straits;
  • Freshwater runoff at Quebec City
  • Atmospheric forecasts from the Global Environmental Multiscale (GEM) model (Canadian Meteorological Centre,  Meteorological Service of Canada, Environment and Climate Change Canada), which provide winds, air temperature, cloud cover, and relative humidity;
  • Sea-ice observations integrated into daily charts from the Canadian Ice Service,  Environment and Climate Change Canada.

St. Lawrence Estuary, from Trois-Rivières to Cap de Bon-Désir
48 hour forecasts

The surface current forecasts for the St. Lawrence Estuary result from a three-dimensional numerical model (Saucier et al. 1999). The ocean model integrates tidal influence and mean freshwater runoff from the St. Lawrence River (no influence of the spring freshet) without wind forcing. Model results were validated with a statistically significant series of drifting buoy tracks in calm weather conditions. Tides are responsible for a high percentage of the current energy in this region, but the forecasts must be used with caution during intense or extreme wind conditions, and in spring freshet conditions.

Water level forecasts, from Montreal to Saint-Joseph-de-la-Rive
30 day forecasts

The water level forecasts for the St. Lawrence River result from a one-dimensional model (Lefaivre et al. 2009) that integrates the flows from Lake Ontario, the Ottawa River basin, and other rivers to the St. Lawrence River. The model integrates the influence of tides and also the atmospheric forcing over the first 48 hours to be able to anticipate storm surges. Model results were validated with observations from the SINECO tide gauge network of the Canadian Hydrographic Service, Quebec region. Moreover, the model assimilates new observations in real time in order to increase its accuracy.

Water levels are shown in real time on the map; levels are colour-coded according to the legend beneath the figure. When a specific point on the map is selected (by a mouse click), a window opens showing that point’s position and the water level (in metres) relative to local Chart Datum. To see the 30 day water level forecast for the selected point, click the link “Time Series Graph”. The model has been validated under a series of scientific and operational research and development programs within the Department of Fisheries and Oceans Canada

Daily freshwater runoff of the St. Lawrence at Quebec city
The daily runoff of the St. Lawrence is calculated using the one-dimensional water level forecast model (Lefaivre et al. 2016). The historical reproduction covers the period from 1968 to 2020. The daily runoff is updated weekly, one week late. The absolute uncertainty is +/- 2000 m3/s at 66% and the relative uncertainty is +/- 100 m3/s at 95%. The water level forecasts model has been validated under a series of scientific and operational research and development programs within the Department of Fisheries and Oceans Canada

To access to the data, click on the “DOWNLOAD” button
It is possible to download images in PNG or GeoTIFF format. The data from which the images are generated are available in free format (text), HDF5, or NetCDF.
The data is the model output on a latitude–longitude grid; data in Text format for the St. Lawrence Estuary is direct model output on its original grid. For details on this grid parameters, please contact us at SINECO@dfo-mpo.gc.ca
It is not yet possible to download water temperature data.
It is not yet possible to download water temperature data.
It is not yet possible to download water level forecasts (images or data).
When using the data, please cite as noted below.


  • Lefaivre, D., D’Astous, A., Matte, P. 2016. Hindcast of Water Level and Flow in the St. Lawrence River over the 2005–2012 period. Atmosphere-Ocean, 54 (3), 264-277
  • Pellerin, P., H. Ritchie, F.J. Saucier, F. Roy, S. Desjardins, M. Valin and V. Lee, 2004: Impact of a two-way coupling between an atmospheric and ocean-ice model over the Gulf of St. Lawrence. Monthly Weather Review, 132(6): 1379-1398.
  • Saucier, F.J., F. Roy, D. Gilbert, P. Pellerin and H. Ritchie, 2003. Modeling the formation and circulation processes of water masses and sea ice in the Gulf of St. Lawrence, Canada. Journal of Geophysical Research, 108(C8): 3269.
  • Saucier, F. J., J. Chassé, M. Couture, R. Dorais, A. D’Astous, D. Lefaivre, and A. Gosselin, 1999. The making of a surface current atlas of the St. Lawrence Estuary, Canada. Fourth international conference on computer modelling of seas and coastal regions (C. A. Brebbia & P. Anagnostopoulos, Eds.), Journal of Computational Mechanics, Wessex Institute of Technology Press, 87-97.
  • Smith, G.C.,  F. Roy, and B. Brasnett, 2013. Evaluation of an operational ice–ocean analysis and forecasting system for the Gulf of St Lawrence. Quarterly Journal of the Royal Meteorological Society, 139(671) Part B: 419-433.

Level of service

The St. Lawrence Global Observatory team maintains and operates the OGSL portal, including the Ocean Forecasts Website, during regular business hours. The OGSL has put in place a monitoring system in order to be notified of any Internet service interruption and has established procedures to ensure that the necessary actions are taken no later than the following business day.
Databases accessible through the OGSL portal are the responsibility of data producers, who ensure their maintenance and take the necessary actions should any interruption occur.

Seasonal Services
Some products and services are only available during specified periods. In these cases, the availability periods are clearly indicated on the site, e.g., Sea Ice Forecast.

Conditions of Use

Identification of the source

Fisheries and Oceans Canada
Cite as:

Joint database from Fisheries and Oceans Canada, Canadian Hydrographic Service, Environment Canada’s Canadian Meteorological Centre and Canadian Ice Service, published on St. Lawrence Global Observatory’s-SLGO portal. [https://slgo.ca]. Accessed [YYYY-MM-DD].