What do the various storm symbols represent?

Green Circles:

The solid dark green circle means that there is 50% chance or greater of hail that is smaller than 19 mm (3/4 of an inch).

The hollow dark green circle means that there is between 30 - 50% chance of hail that is smaller than 19 mm.

The solid light green circle means that there is 50% chance or greater of severe hail (hail that is 19 mm or larger).

The hollow light green circle means that there is between 30 - 50% chance of severe hail (hail that is 19 mm or larger).

Coloured Rings:

The broken rings are shown when the base of a mesocyclone (a rotating thunderstorm) is aloft (ie. not on the lowest tilt).

The solid rings are shown when the mesocyclone base is on the lowest tilt.

The color "heat" of the icon represents the strength (very weak is light green, weak is green, moderate is yellow, strong is red, extreme is purple). GRLevel3 uses the "strength rank", SR, to choose an icon. The first icon is shown for SR values of 1-2, second for SR values 3-4, third for 5-6, fourth for 7-8, and fifth icon for 9 and above.

Tornado Vortex Signature (TVS)- Area defined on radar to have strong low level rotation and may have the potential to produce a tornado. Also known as a "Doppler-indicated tornado." These should be monitored very closely. Keep in mind that these sometimes show up and then quickly disappear; it does not mean that the storm is indeed producing a tornado.

GRLevel3 Radar Legend

 

WEATHER WARNING NOTIFICATIONS
  Tornado Warning   Avalanche Warning   Blizzard Warning
  Winter Storm Warning   Severe Thunderstorm Warning   High Wind Warning
  Storm Warning   High Surf Warning   Flood Warning
  Gale Warning   Hazardous Seas Warning   Wind Chill Warning
  Hard Freeze Warning   Freeze Warning   Heavy Freezing Spray Warning
  Fire Weather Warning   Red Flag Warning   Flash Flood Warning
  Marine Warning        
 
WEATHER ADVISORIES NOTIFICATIONS
  Flood Advisory   High Surf Advisory   Winter Weather Advisory
  Small Craft Advisory   Brisk Wind Advisory   Dense Fog Advisory
  Wind Advisory   Freezing Fog Advisory   Freezing Rain Advisory
  Air Stagnation Advisory   Wind Chill Advisory   Lake Effect Snow Advisory
  Lake Wind Advisory        
 
WEATHER WATCH NOTIFICATIONS
  Tornado Watch   Flood Watch   High Wind Watch
  Gale Watch   Hard Freeze Watch   Freeze Watch
  Fire Weather Watch   Avalanche Watch   Winter Storm Watch
  Severe Thunderstorm Watch   Hazardous Seas Watch    
 
OTHER WEATHER NOTIFICATIONS
  Air Quality Alert   Special Weather Statement   Coastal Flood Statement
  Short Term Forecast