METEOROLOGY FLIGHT PLANNING
Other unique features of the NEXRAD provide the capability to display areas of hail, tornadoes,
wind shear, and microbursts (Figure 2-12). This type of information is particularly useful in
planning a flight around known areas of potentially dangerous weather conditions.
Figure 2-13 Hook Echo on NEXRAD
The structure of a storm can provide clues to the potential for hail. Hailstorms have intense
cores, generally between 2 and 5 NM in diameter, and usually begin developing at higher
altitudes and descend toward the base of a storm. Very high reflectivity values (over 55 dbz)
may also indicate that the precipitation is in the form of hail. Thunderstorms with strong
updrafts, extensive vertical height, high liquid water content, and large cloud drop sizes are
favorable conditions for the formation of hail.
The NEXRAD system does not directly observe tornadic circulation; however, the system can
display what is referred to as a "hook echo" that is considered indicative of a tornado. In Figure
2-12, a dark shaded hook echo is evident just west-southwest of MOB. This echo actually
resulted in a tornado that caused severe property damage and injuries to personnel. A pilot
2-14 DATA DISPLAYED ON WEATHER IMAGERY PRODUCTS