Fig. 43. Winds aloft at 10:00 P. M. on April 23 (CST). Winds at 2,000 feet above mean sea level are shown in black; those at 4,000 feet, in white. Velocities are indicated by standard Beaufort Scale of Wind Force. The numbers in circles refer to the stations shown in [Figure 42].

Fig. 44. Comparison of flight trends and surface weather conditions on April 24-25, 1948. The meteorological data were taken from the U. S. Weather Bureau Daily Weather Map for 12:30 A. M. (CST) on April 25. The nightly station densities and the average hourly station density (shown in parentheses) are as follows:

1. Albion: migration negligible12. Rosedale: 1,100 (100)
2. Ottumwa: 4,600 (1,500)14. Mansfield: 1,700 (400)
3. Columbia: 1,400 (400)18. Pensacola: migration negligible
5. Louisville: 1,700 (200)21. Winter Park: 600 (100)
10. Memphis: 6,600 (900)24. Progreso: 27,300 (3,000)

Fig. 45. Winds aloft at 10:00 P. M. on April 24 (CST). Winds at 2,000 feet above mean sea level are shown in black; those at 4,000 feet, in white. Velocities are indicated by standard Beaufort Scale of Wind Force. The numbers in circles refer to the stations shown in [Figure 44].