INSTRUMENTS FLIGHT PLANNING
First, check the overall synoptic pattern or general weather picture, both at the surface and aloft.
Look for the location, movement, and intensity of weather areas and their effect on your
proposed route and destination. Select the best area for an alternate airfield.
Check the Weather Depiction Chart for the location of IFR and VFR areas along your proposed
route and near your destination. It is issued every three hours, and shows, at a glance, the
distribution of weather and cloud coverage for the United States and Canada. Additionally, it
gives the ceiling and visibility for airports in this area.
Figure 7-1 Weather Depiction Chart
Two sets of lines are drawn on the chart. The area enclosed by the solid line, colored red by the
weather office, contains IRF airports (i.e., have ceilings of less than 1000 feet, visibility of less
than 3 miles, or both). The area enclosed by the scalloped line, colored blue by the weather
office, contains MVFR airports, but have ceilings of between 1000 and 3000 feet. The area
outside the scalloped line is VFR with ceilings greater than 3000 feet. Thus, the Weather
Depiction Chart readily delineates the location of IFR and VFR areas and provides ceiling,
visibility, and cloud cover information for individual stations.
7-2 IN-FLIGHT WEATHER ANALYSIS