Monthly and Seasonal Forecasts

Temperature and Precipitation Probabilistic Forecasts

What do these maps represent ?
The probabilities for the below, near or above normal tercile categories are shown for temperature and precipitation for various lead times, ranging from months 1-3 of the forecast period to months 10-12. In each case, 4 maps and a reliability diagram are shown. The first map displays at each location the probability for the most likely category. (The map for 1-3 month temperatures is reproduced at the top of this page.) In these maps, white over Canada represents regions of "equal chance" where forecast probabilities for none of the three categories exceed 40%, and hence where the categories are nearly equally probable. The occurrence of the white colour areas over Canada is more predominant for precipitation forecasts, which are generally less skillful than temperature forecasts, and increases with forecast range at longer lead times. The increasing occurrence of areas coloured in white over Canada implies diminishing ability of the forecasting system to make reliable and accurate predictions in these regions.

The next 3 maps show the probabilities for each category individually.

Finally, the reliability diagram, also known as attributes diagram, shows, for all locations in Canada, the frequency with which each category occurs (vertical axis) versus the probability with which it was forecast (horizontal axis). Ideally, the observed frequencies should equal the forecast probabilities, in which case the dots in the reliability diagrams would lie along the diagonal dashed line. To improve this property of the forecasts, a calibration method has been applied. To use the forecasts optimally it is strongly recommended to read carefully the user guide!

How are these forecasts produced?
The seasonal forecasts are based on a 20-member ensemble of predictions, 10 members from each of two coupled atmosphere-ocean-land physical climate models. The forecast probabilities are estimated by first computing the anomalies or departures from normal for each ensemble member and then applying the calibration procedure to these values. (Forecast probabilities prior to June 2013 were uncalibrated, and obtained by counting the ensemble members in each of the three categories and then dividing by the ensemble size.)

Temperature and Precipitation Deterministic Forecasts

What do these maps represent ?
The upper panel shows the seasonal air temperature or precipitation anomaly forecasts. The forecasts are presented in 3 categories: below normal, near normal and above normal. The lower panel illustrates the skill (percent correct) associated to the forecast.The forecast values for more than 100 locations in Canada are also shown at the "List" links.
Please take into account the skill map (lower panel) when you use the forecast map (upper panel). To use the forecasts optimally it is strongly recommended to read carefully the user guide.

How are these forecasts produced ?
The forecasts are based on the average of 10-member ensembles of forecasts produced with each of two coupled atmosphere-ocean-land physical climate models. Note that the category of the forecast ensemble average, shown in the deterministic forecast maps, may sometimes differ from the most probable category in the probabilistic forecast maps.

Skill of the Deterministic Forecast System

What do these maps represent ?
By clicking on the above links, you can see the spatial skill distribution of the forecast system. The colored areas show that the system is better than pure chance forecast while the grey areas indicate the areas where the current forecast system has no predictive skill. Please read the page on Long-Range Forecast Skill Maps before doing further interpretation of the maps.

Verification of Past Forecasts

Using this menu, you can see the previous 1-3 month forecast charts produced by Environment Canada since 1996 and the corresponding observed charts. The scores (from the contingency tables) obtained with these forecasts are also available. To see your selection please click the view button.

Climatology of Temperature and Precipitation

What do these maps represent?
By clicking on the links under "Average" you can see a map of mean observed value of temperature (in degrees Celsius) or precipitation accumulation(in millimetre or mm) for the corresponding season. The Canadian surface stations data used cover the 1981-2010 period for both the temperature and the precipitation.

The links under "Threshold" present maps of the value used as a threshold to classify the observed anomaly in one of the three categories (above, near or below normal). The climatology and threshold values for more than 100 locations in Canada are also shown at the links under "Table". The 1981-2010 climatology is now the reference climatology. Before 1 December 2011 a 1971-2000 climatology was used.

How do this climatology was produced?
The climatology was produced using homogenized data coming from the National Climate Data and Information Archive. To know more about homogenized climatological data refer to the following publication Éva Mekis & Lucie A. Vincent (2011): An overview of the Second Generation Adjusted Daily Precipitation Dataset for Trend Analysis in Canada, Atmosphere-Ocean, 49:2, 163-177.

Composite analysis of Continental Snow Coverage, Sea Ice Coverage, and Sea Surface Temperature Anomalies

Static Images: daily and the 30-Day average
Animations (JavaScript Required)

One-year animation of SST Anomalies, Snow Coverage, and Sea Ice Coverage (Pacific Ocean and the Americas). This animation is well suited to observing the ENSO SST Anomaly phenomenon during El-Niño/La Niña years. It also displays the yearly cycle of snow coverage over the northern landmasses.

30-day animation of SST anomalies, Snow Coverage, and Sea Ice Coverage (North America). One can observe the progression or retreat of the snow coverage over North America during the past month.

The climate of Canada is mainly influenced by the sea surface temperature and the sea ice extent of the surrounding seas as well as by the snow cover. Using the above links, you can have access to maps of the current state of these fields as analysed by the CMC. You can also look at some animations to follow the evolution of the conditions during the last months.

On-line Model Data

As a Global Producing Center of Long-Range Forecasts certified by WMO (World Meteorological Organization), the MSC (Meteorological Service of Canada) gives access to its forecast the first day of each month. The forecast fields from the models and the corresponding hindcast are available in GRIB format on the MSC numerical output database.

Forecast are also available at the Canadian Center for Climate Modeling and Analysis Database. The historical forecast for 1981-2010 produced by the coupled prediction models for the phase 2 of the Coupled Historical Forecasting Project (CHFP2) are also available on this site. The model climatologies used to calculate the forecast anomalies and to draw the skill maps are obtained from the 1981-2010 CHFP2 historical forecast.

Environment Canada El Niño and La Niña pages

The ENSO phenomenon (El Niño and La Niña) is one of the major factors influencing the year to year fluctuations of seasonal temperature and precipitation anomalies in Canada. You can learn more about the worldwide and regional effects of the phenomena as well as follow its evolution by going to the Environment Canada web pages listed above.

Environment Canada Climate Trends and Variations Bulletin

For a review of past conditions of temperature and precipitation, you are invited to look at official trends and variations bulletin of Environment Canada.