Extreme index ratios
Help - Canadian station weather data and extreme winter events

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These "extreme index ratios" are fundamental to understanding this analysis. A ratio here shows how often a type of weather event occurs in a station record on days when a teleconnection index is in an extreme high state versus the days when that weather event occurs with that index in an extreme low state. An explanation of the red/blue color scheme used with the ratios is given below.

For example, how often for a station extreme low TMIN occurs on extreme high PNA days versus on extreme low PNA days is shown by the extreme low TMIN PNA ratio. For each extreme of each weather variable (low and high temperatures and high and any precipitation), there are such ratios for each teleconnection index.

See these links for more information on extreme weather events and extreme index days

Red, Blue, and the Ratios
All ratios are shown as decimel numbers of 1 or greater. To show whether in the ratio there were more days with extreme high index or extreme low index a simple color scheme is used. Ratio colors are shown by cell background colors in tables and by circle marker colors on maps. Rare cases where the ratio is exactly 1 are shown in tables with white cell backgrounds and are not shown on maps.