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Amarillo, TX during the late morning. A strong convergencezone formed in northeast New Mexico and <br />extended into the northwest portion of the Texas Panhandle due to the approaching shortwave and the warm <br />front associated with the Low in southeast New Mexico. With surface CAPE values near 1500 J/Kg convective <br />clouds began to form near Clovis, NM and the decision to scramble Seed 3 was made around 19Z. By 20:35 <br />GMT Seed 1 had selected a favorable area of clouds and wanted to work it, but the seeder determined that the <br />bases were not firm enough. Seed 1 then went to a more developed cloud to the NE, but its base was again not <br />well formed and it was too close to a monster Cb. All these searches were done at 11,000’ while monitoring <br />control clouds. Cloud base was at about 9000’. A third cloud to the southwest was selected at 20:50 and seeded <br />starting at 20:52. Seed 1 monitored the cloud at 11 kft and got a strong SF6 hit at 20:58:15, 5.5 minutes after <br />seeding commencement. The hit was obtained just after flying downshear (east) and encountering a heavy <br />precipitation shaft with some small hail from the cloud that was growing explosively above. Seed 1 turned away <br />sharply from that location back upshear in the cloud and there found a major hit of SF gas. The hit could not be <br />6 <br />found again, probably because Seed 1 did not dare to fly again sufficiently far downshear in the vigorous cloud. <br />Seed 1 then ascended to 13 kft continuing the search for other hits until it was realized that the cloud had <br />become too active for continue safe penetration. In any case the material must have long since been carried up <br />into the cloud. We left the cloud at 21:11 in search for a second case, 9 minutes after the seeding of the first <br />cloud. Documentation of the apparent effect of the salt hygroscopic seeding on cloud microphysics is presented <br />here in Figure 14. <br />Figure 14. Plots of the flights tracks of the seeder in yellow (Seed 3) and cloud physics in green (Seed 1) aircraft <br />for the first seeded experimental unit obtained on May 31, 2005. The short segment of the green flight track that <br />appears in red is the region where the SF gas was detected. <br />6 <br />39 <br />