FIGURE 8.20 A series of wave cyclones (a “family” of cyclones) forming along the polar front. Fig. 8-20, p.221

FIGURE 8. 21 (a) Typical paths of winter mid-latitude cyclones FIGURE 8.21 (a) Typical paths of winter mid-latitude cyclones. The lows are named after the region where they form. Fig. 8-21a, p.222

divergence convergence H L L H convergence divergence

Wind is speeding up Wind is slowing down subgeostrophic winds

subgeostrophic winds Wind is speeding up Wind is slowing down converging diverging

divergence convergence

FIGURE 10.1 Simplified model depicting the life cycle of an ordinary thunderstorm that is nearly stationary. (Arrows show vertical air currents. Dashed line represents freezing level, 0°C isotherm.) Fig. 10-1, p.259

Fig. 10-31, p.283 Fig. 10-32, p.283

FIGURE 10.12 An enhanced infrared satellite image showing a prefrontal squall-line (in dark red) that stretches from the Ohio Valley into the southern United States. Fig. 10-12, p.266

FIGURE 10.13 Pre-frontal squall-line thunderstorms may form ahead of an advancing cold front as the upper-air flow develops waves downwind from the cold front. Fig. 10-13, p.266

FIGURE 10.14 An enhanced infrared satellite image showing a Mesoscale Convective Complex (dark red color) extending from central Kansas across western Missouri. This organized mass of thunderstorms brought hail, heavy rain, and flooding to this area. Fig. 10-14, p.267

FIGURE 10. 10 Flying into a microburst FIGURE 10.10 Flying into a microburst. At position (a), the pilot encounters a headwind; at position (b), a strong downdraft; and at position (c),a tailwind that reduces lift and causes the aircraft to lose altitude. Fig. 10-10, p.265

FIGURE 10.11 Doppler radar display showing a line of thunderstorms(a squall line) bent in the shape of a bow (colors red, orange, and yellow)as they move eastward across the San Joaquin Valley of California. Such bow echos often produce damaging surface winds near the center of the bow. Sometimes the left (usually northern) end of the bow will develop cyclonic rotation and produce a tornado. Fig. 10-11, p.266

FIGURE 10.19 The generalized charge distribution in a mature thunderstorm. Fig. 10-19, p.272

FIGURE 10. 20 The development of a lightning stroke FIGURE 10.20 The development of a lightning stroke. (a) When the negative charge near the bottom of the cloud becomes large enough to overcome the air’s resistance, a flow of electrons—the stepped leader—rushes toward the earth.(b) As the electrons approach the ground, a region of positive charge moves up into the air through any conducting object, such as trees, buildings, and even humans. (c) When the downward flow of electrons meets the upward surge of positive charge, a strong electric current—a bright return stroke—carries positive charge upward into the cloud. Fig. 10-20, p.273

FIGURE 10.24 Cloud-to-ground lightning strikes in the vicinity of Chicago, Illinois, as detected by the National Lightning Detection Network. Fig. 10-24, p.275

FIGURE 10.22 The lightning rod extends above the building, increasing the likelihood that lightning will strike the rod rather than some other part of the structure. After lightning strikes the metal rod, it follows an insulated conducting wire harmlessly into the ground. Fig. 10-22, p.274