Radar Summary Chart


  • A radar summary chart is a graphical depiction display of collections of automated radar weather reports (SD/ROB)
Radar Summary Chart
Figure 1: Radar Summary Chart

Issuance & Validity:

  • Issued every hour
  • Information is about 35 minutes old
  • Information is all observed data
  • Should be used as a supplement to other preflight weather data


  • A legend is printed on the chart
  • It displays areas of precipitation, type, intensity, configuration, coverage, tops and cell movements of precipitation


  • Shows positions and types of fronts
  • A three-digit number near a front classifies it as to type, intensity, and character enclosed in brackets ([ or ])

Precipitation Echo Type
Figure 2: Precipitation Echo Type


  • Intensity is obtained from the amount of energy returned to the radar from the target and is indicated by chart contours

Precipitation Intensity
Figure 3: Precipitation Intensity


  • Precipitation Echo Type:
    • Types of precipitation are located adjacent to the precipitation areas
  • Echo Configuration and Coverage:
    • Three designated arrangements: a LINE of echoes, an AREA of echoes, and an isolated CELL
    • All the hatched area inside the contours is considered to be covered by echoes
    • When reported as a LINE, a line will be drawn through them on the chart
    • When there is 8/10ths coverage or more the line is labeled as solid (SLD) at both ends
  • Echo Tops:
    • Tops are obtained from radar and satellite data
    • Max heights of the precipitation in hundreds of feet MSL
    • They are only approximations
    • The height displayed is the highest in the indicated areas
    • Tops are entered above a short line
    • 220: Maximum top 22,000 feet
  • Echo Movement:
    • Cell movement is indicated by an arrow with the speed in knots entered at the top of the arrow head
    • Little movement is identified by LM
    • Line or area movement is no longer indicated on the chart

Severe Weather Watch Areas:

  • Outlined by heavy dashed lines, usually in a rectangular box
  • Two types: Tornado watches and severe thunderstorm watches
  • "WS0005 = Thunderstorm watch and is the 5th watch issued so far this year
  • The watch number is also printed at the bottom of the chart (in Mexico) together with the issuance time and expiration time

Using The Chart:

  • Aids in preflight planning by identifying areas of precipitation and/or thunderstorms
  • Displays drops or ice particles of precipitation size only
  • Does not display clouds and fog therefore no echoes does not imply clear weather
  • Cloud tops will most likely be higher than the tops of the precipitation echoes detected by radar


  • Solid lines enclose precipitation areas
  • Symbols specify the forums and types of precipitation
  • A mix is indicated by the use of two pertinent symbols separated by a slash
  • Areas of continuous precipitation is shaded as well as precipitation covering more than half of the area
  • A bold dashed line is used to separate precipitation with contrasting characteristics
  • A dashed line would be used to separate an area of similar characteristics (snow and rain)

Weather Flying Categories:

  • Ceiling and visibility determine the category
    • VFR: Visual Flight Rules
      • VFR areas are those areas not enclosed by either dashed or solid lines
    • MVFR: Marginal Visual Flight Rules
      • MVFR areas are enclosed by dashed lines
    • IFR: Instrument Flight Rules
      • IFR areas are enclosed by solid lines

Freezing Levels:

  • Freezing levels are depicted by a zigzag line labeled as "SFC"
  • Freezing levels aloft are depicted by thin, short dashed lines
  • Lines are drawn at 4,000 ft intervals (80 = 8,000 ft)
  • Lines are discontinued where they intersect corresponding altitudes of the Rocky Mountains
  • Areas with multiple freezing levels have lines drawn to the highest freezing level


  • Areas of moderate or greater turbulence are enclosed by bold, long dashed lines
  • Turbulence intensities are identified by symbols
  • The vertical extend of turbulence layers are specified by top and base heights
  • Areas of thunderstorms do not include indications of turbulence because it is implied
  • Added emphasis is included if the turbulence is form the surface to above 24,000' having thunderstorms covering more than half of the area
  • Intensity symbols and layer altitudes appear within or adjacent to the forecast areas