Radar rain/snow rate and loop controls.

Rain and snow rate

The intensity of the echo (or reflection) depends on how well the precipitation acts as a mirror. Large forms like hail and large wet snowflakes are very efficient because of their size; dry snow, rain and drizzle are less so.

In general, radar estimates of precipitation rate will be less accurate in convective weather where hail or snow pellets are present or when snow is melting at low elevations in winter storms.

Two different scales can be applied to the radar echo intensity. By default, a rain scale is applied for April-Oct and a snow scale for Nov-Mar regardless of location or local temperatures. Adjust the rain or snow setting on the View menu to suit local conditions given by weather stations.

Time menu for the real time view (the date/time entry form is hidden)

The length of the loop. The default is 2 1/2 hours with an image every 6 minutes (10 minutes before Aug 2024). This roughly matches the 2 1/2 hour default setting for observations from the 10 minute automated weather stations 'MSC auto 10 minutes'.

toggle and set-toggle

The toggle button flips between the most recent radar image to the image produced one hour earlier. Use it to estimate the future position of an area of precipitation one or two hours into the future. Individual showers often move faster than a line of showers. The toggle button can show that the line of showers are approaching more slowly than a quick look at individual showers would indicate.

The set-toggle button changes the default of one hour to any other image in the loop. To set the toggle to two hours, stop the animation and set the displayed image to two hours ago and then press the set-toggle button.

Some websites have an automated version of this where they take the last radar image and move it along into the future at the speed and direction estimated from earlier images.