Technical Reports Document Library

The 2009 season marked year number eight for cloud seeding operations for the STWMA in the EAA’s trl-county area of Bandera, Bexar and Medina. … The latter half of May saw several disturbances affecting the area, bringing a number of seeding opportunities to the target area including one randomized seeding case. …Toward the end of [June] a couple more days of favorable weather al lowed for seeding operations. …By the end of [August}, San Antonio had recorded its warmest June to August period since record keeping began. …

Tropical moisture, which had been largely absent for much of the summer, also began to affect the area with showers and thunderstorms dropping heavier amounts of rain than had been seen all summe [in September]. While this was certainly good news for the area, in terms of cloud seedability the highly tropical air mass produced many unfavorable clouds for treatment. … There was one more randomized case on the 1^st.

With the conclusion of the season, radar data from the TITAN machine were sent to Archie Ruiz, who works for Active Influence performing radar evaluations for the Texas weather modification projects. Despite the dry weather experienced much of the season, the analysis does indicate increases in rainfall from the clouds that were able to be seeded.

The STWMA continued with an experiment within the EAA target area where randomized seeding would take place. …Radar data from each day was also to be saved, again for future analysis.

2009 saw only two randomized seeding cases coming to fruition. The continuing problem of clouds developing in clusters as opposed to being isolated resulted in many “no-case” days.