Characteristics of extratopical cyclones can be seen in this atlas. This includes a composite storm, which comes from an average of over 200 extratropical storms in the North Atlantic between 1989 and 2009. The most intense storms - those achieving the greatest 850 hPa relative vorticity - have been selected. Data from any of the top 200 storms can also be viewed by selecting a storm from either the form or google map below.

Once a storm has been selected, various measurements and vertical and horizontal cuts of these measurements can be selected. The evolution of cyclonic structure and air flows, such as the warm and cold conveyor belts and dry intrusion are illustrated by conceptual diagrams. The method used to create the atlas is described here.

Composite storm

The maximum intensity for each storm (where the potential vorticity was greatest) has been used to align all the storms before averaging was done to produce the composite data in this database. The offset then refers to the number of hours before or after the maximum intensity. Hence an offset of -12 hours is the average of all storms 12 hours before they reached their maximum intensity.

To select an offset, please either click on the figure below or on the buttons on the left.

Offset components
-60 -48 -36 -24 -12 0 12 24 36 48 60
-60hr -48hr -36hr -24hr -12hr 0hr 12hr 24hr 36hr 48hr 60hr

Top 200 storms

Please select the storm require either using the form below

Storm:  .

or select a storm by clicking on the map below. When storms tracks are close together, it is likely that only the strongest storms can be selected. The current selected storm should appear in red. The filter above may be useful by reducing the number of storm tracks displayed.

Filter:   storms ;   first season ;   last season .